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  • Novel insights into expansion and functional diversification of MIR169 family in tomato
    Planta (IF 3.060) Pub Date : 2020-01-24
    Sombir Rao, Sonia Balyan, Sarita Jha, Saloni Mathur

    Abstract Main conclusion Expansion of MIR169 members by duplication and new mature forms, acquisition of new promoters, differential precursor-miRNA processivity and engaging novel targets increase the functional diversification of MIR169 in tomato. Abstract MIR169 family is an evolutionarily conserved miRNA family in plants. A systematic in-depth analysis of MIR169 family in tomato is lacking. We report 18 miR169 precursors, annotating new loci for MIR169a, b and d, as well as 3 novel mature isoforms (MIR169f/g/h). The family has expanded by both tandem- and segmental-duplication events during evolution. A tandem-pair MIR169b/b-1 and MIR169b-2/h is polycistronic in nature coding for three MIR169b isoforms and a new variant miR169h, that is evidently absent in the wild relatives S. pennellii and S. pimpinellifolium. Seven novel miR169 targets including RNA-binding protein, protein-phosphatase, aminotransferase, chaperone, tetratricopeptide-repeat-protein, and transcription factors ARF-9B and SEPELLATA-3 were established by efficient target cleavage in the presence of specific precursors as well as increased target abundance upon miR169 chelation by short-tandem-target-mimic construct in transient assays. Comparative antagonistic expression profiles of MIR169:target pairs suggest MIR169 family as ubiquitous regulator of various abiotic stresses (heat, cold, dehydration and salt) and developmental pathways. This regulation is partly brought about by acquisition of new promoters as demonstrated by promoter MIR169:GUS reporter assays as well as differential processivity of different precursors and miRNA cleavage efficiencies. Thus, the current study augments the functional horizon of MIR169 family with applications for stress tolerance in crops.

    更新日期:2020-01-24
  • Deficiency of GDP- l -galactose phosphorylase, an enzyme required for ascorbic acid synthesis, reduces tomato fruit yield
    Planta (IF 3.060) Pub Date : 2020-01-22
    Matías L. Alegre, Charlotte Steelheart, Pierre Baldet, Christophe Rothan, Daniel Just, Yoshihiro Okabe, Hiroshi Ezura, Nicholas Smirnoff, Gustavo E. Gergoff Grozeff, Carlos G. Bartoli

    Abstract Main conclusion Reduced GDP-l-galactose phosphorylase expression and deficiency of ascorbic acid content lead to decreased fruit set and yield in tomato plants. Abstract Reduced GDP-l-galactose phosphorylase expression and deficiency of ascorbic acid content lead to decreased fruit set and yield in tomato plants. GDP-l-galactose phosphorylase (GGP) catalyzes the first step committed to ascorbic acid synthesis. The participation of GDP-l-galactose phosphorylase and ascorbate in tomato fruit production and quality was studied in this work using two SlGGP1 deficient EMS Micro-Tom mutants. The SlGGP1 mutants display decreased concentrations of ascorbate in roots, leaves, flowers, and fruit. The initiation of anthesis is delayed in ggp1 plants but the number of flowers is similar to wild type. The number of fruits is reduced in ggp1 mutants with an increased individual weight. However, the whole fruit biomass accumulation is reduced in both mutant lines. Fruits of the ggp1 plants produce more ethylene and show higher firmness and soluble solids content than the wild type after the breaker stage. Leaf CO2 uptake decreases about 50% in both ggp1 mutants at saturating light conditions; however, O2 production in an enriched CO2 atmosphere is only 19% higher in wild type leaves. Leaf conductance that is largely reduced in both mutants may be the main limitation for photosynthesis. Sink-source assays and hormone concentration were measured to determine restrictions to fruit yield. Manipulation of leaf area/fruit number relationship demonstrates that the number of fruits and not the provision of photoassimilates from the source restricts biomass accumulation in the ggp1 lines. The lower gibberellins concentration measured in the flowers would contribute to the lower fruit set, thus impacting in tomato yield. Taken as a whole these results demonstrate that ascorbate biosynthetic pathway critically participates in tomato development and fruit production.

    更新日期:2020-01-23
  • Plant responses to decadal scale increments in atmospheric CO 2 concentration: comparing two stomatal conductance sampling methods
    Planta (IF 3.060) Pub Date : 2020-01-16
    Sven Peter Batke, Charilaos Yiotis, Caroline Elliott-Kingston, Aidan Holohan, Jennifer McElwain

    Our study demonstrated that the species respond non-linearly to increases in CO2 concentration when exposed to decadal changes in CO2, representing the year 1987, 2025, 2051, and 2070, respectively.

    更新日期:2020-01-17
  • Late-maturity α-amylase expression in wheat is influenced by genotype, temperature and stage of grain development
    Planta (IF 3.060) Pub Date : 2020-01-16
    Adinda P. Derkx, Daryl J. Mares

    Abstract Main Conclusion Late-maturity α-amylase (LMA) expression in wheat grains can be induced by either a cool temperature shock close to physiological maturity or continuous cool maximum temperatures during grain development. Abstract Late-maturity α-amylase (LMA) is a genetic trait in wheat (Triticum aestivum L.) involving the production of α-amylase during grain development, which can result in an unacceptably low Falling Number (FN) in mature grain and consequent grain downgrading. Comparison of the FN test, an α-amylase activity assay and a high pI α-amylase-specific ELISA on the same meal samples gave equivalent results; ELISA was used for further experiments because of its isoform specificity. A cool temperature shock during the middle stages of grain development is known to induce LMA and is used for phenotypic screening. It was determined that a cool temperature treatment of seven days was required to reliably induce LMA. Glasshouse studies performed in summer and winter demonstrated that temperature affected the timing of sensitivity to cool-shock by altering the rate and duration of grain development, but that the sensitive grain developmental stage was unchanged at 35–45% moisture content. Wheat varieties with Rht-B1b or Rht-D1b dwarfing genes responded to a cool-shock only from mid grain filling until physiological maturity, whilst genotypes with Rht8c or without a dwarfing gene expressed LMA in response to a cool-shock during a wider developmental range. A continuous cool maximum temperature regimen (23 °C/15 °C day/night) during grain development also resulted in LMA expression and showed a stronger association with field expression than the cool-shock treatment. These results clarify how genotype, temperature and grain developmental stage determine LMA expression, and allow for the improvement of LMA phenotypic screening methods.

    更新日期:2020-01-17
  • Fusarium oxysporum infection activates the plastidial branch of the terpenoid biosynthesis pathway in flax, leading to increased ABA synthesis
    Planta (IF 3.060) Pub Date : 2020-01-16
    Aleksandra Boba, Kamil Kostyn, Bartosz Kozak, Wioleta Wojtasik, Marta Preisner, Anna Prescha, Edyta M. Gola, Dzmitry Lysh, Barbara Dudek, Jan Szopa, Anna Kulma

    Upregulation of the terpenoid pathway and increased ABA content in flax upon Fusarium infection leads to activation of the early plant’s response (PR genes, cell wall remodeling, and redox status).

    更新日期:2020-01-17
  • Generation of fruit postharvest gene datasets and a novel motif analysis tool for functional studies: uncovering links between peach fruit heat treatment and cold storage responses
    Planta (IF 3.060) Pub Date : 2020-01-16
    Mauro Gismondi, Lucas D. Daurelio, Claudia Maiorano, Laura L. Monti, Maria V. Lara, Maria F. Drincovich, Claudia A. Bustamante

    Abstract Main Conclusion A survey of developed fruit gene-specific datasets and the implementation of a novel cis-element analysis tool indicate specific transcription factors as novel regulatory actors under HT response and CI protection. Abstract Heat treatment (HT) prior to cold storage (CS) has been successfully applied to ameliorate fruit chilling injury (CI) disorders. Molecular studies have identified several HT-driven benefits and putative CI-protective molecules and mechanisms. However, bioinformatic tools and analyses able to integrate fruit-specific information are necessary to begin functional studies and breeding projects. In this work, a HT-responsive gene dataset (HTds) and four fruit expression datasets (FEds), containing gene-specific information from several species and postharvest conditions, were developed and characterized. FEds provided information about HT-responsive genes, not only validating their sensitivity to HT in different systems but also revealing most of them as CS-responsive. A special focus was given to peach heat treatment-sensitive transcriptional regulation by the development of a novel Perl motif analysis software (cisAnalyzer) and a curated plant cis-elements dataset (PASPds). cisAnalyzer is able to assess sequence motifs presence, localization, enrichment and discovery on biological sequences. Its implementation for the enrichment analysis of PASPds motifs on the promoters of HTds genes rendered particular cis-elements that indicate certain transcription factor (TF) families as responsible of fruit HT-sensitive transcription regulation. Phylogenetic and postharvest expression data of these TFs showed a functional diversity of TF families, with members able to fulfil roles under HT, CS and/or both treatments. All integrated datasets and cisAnalyzer tool were deposited in FruitGeneDB (https://www.cefobi-conicet.gov.ar/FruitGeneDB/search1.php), a new available database with a great potential for fruit gene functional studies, including the markers of HT and CS responses whose study will contribute to unravel HT-driven CI-protection and select tolerant cultivars.

    更新日期:2020-01-17
  • Computational screening of miRNAs and their targets in leaves of Hypericum spp. by transcriptome-mining: a pilot study
    Planta (IF 3.060) Pub Date : 2020-01-14
    Linda Petijová, Zuzana Jurčacková, Eva Čellárová

    Abstract Main conclusion Our work provides a survey of mature miRNAs, their target genes and primary precursors identified by in-silico approach in leaf transcriptomes of five selected Hypericum species. Abstract MiRNAs are small non-coding RNA molecules found in animals, terrestrial plants, several algae and molds. As their role lies in the post-transcriptional gene silencing, these tiny molecules regulate many biological processes. Phyto-miRNAs are considered the important regulators of secondary metabolism in medicinal plants. The genus Hypericum comprises many producers of bioactive compounds, mainly unique naphtodianthrones with a great therapeutic potential. The main goal of our work was to identify genetically conserved miRNAs, characterize their primary precursors and target sequences in the leaf transcriptomes of five Hypericum species using in-silico approach. We found 20 sequences of potential Hypericum pri-miRNAs, and predicted and computationally validated their secondary structures. The mature miRNAs were identified by target genes screening analysis. Whereas predicted miRNA profiles differed in less genetically conserved families, the highly conserved miRNAs were found in almost all studied species. Moreover, we detected several novel highly likely miRNA–mRNA interactions, such as mir1171 with predicted regulatory role in the biosynthesis of melatonin in plants. Our work contributes to the knowledge of Hypericum miRNAome and miRNA–mRNA interactions.

    更新日期:2020-01-14
  • “Help is in the air”: volatiles from salt-stressed plants increase the reproductive success of receivers under salinity
    Planta (IF 3.060) Pub Date : 2020-01-13
    Marco Landi, Fabrizio Araniti, Guido Flamini, Ermes Lo Piccolo, Alice Trivellini, Maria Rosa Abenavoli, Lucia Guidi

    Salinity alters VOC profile in emitter sweet basil plants. Airborne signals by emitter plants promote earlier flowering of receivers and increase their reproductive success under salinity.

    更新日期:2020-01-13
  • Identification and characterization of circular RNAs during wood formation of poplars in acclimation to low nitrogen availability
    Planta (IF 3.060) Pub Date : 2020-01-10
    Huimin Liu, Wanwen Yu, Jiangting Wu, Zhuorong Li, Hui Li, Jing Zhou, Jingjing Hu, Yan Lu

    Circular RNA (circRNA) identification and expression profiles, and construction of circRNAs-miRNAs-mRNAs networks indicates that circRNAs are involved in wood formation of poplars in acclimation to low nitrogen availability.

    更新日期:2020-01-11
  • Genome-wide characterization of the laccase gene family in Setaria viridis reveals members potentially involved in lignification
    Planta (IF 3.060) Pub Date : 2020-01-09
    Marcella Siqueira Simões, Gabriel Garon Carvalho, Sávio Siqueira Ferreira, José Hernandes-Lopes, Nathalia de Setta, Igor Cesarino

    Abstract Main conclusion Five laccase genes are potentially involved in developmental lignification in the model C4 grass Setaria viridis and their different tissue specificities suggest subfunctionalization events. Abstract Plant laccases are copper-containing glycoproteins involved in monolignol oxidation and, therefore, their activity is essential for lignin polymerization. Although these enzymes belong to large multigene families with highly redundant members, not all of them are thought to be involved in lignin metabolism. Here, we report on the genome-wide characterization of the laccase gene family in the model C4 grass Setaria viridis and further identification of the members potentially involved in monolignol oxidation. A total of 52 genes encoding laccases (SvLAC1 to SvLAC52) were found in the genome of S. viridis, and phylogenetic analyses showed that these genes were heterogeneously distributed among the characteristic six subclades of the family and are under relaxed selective constraints. The observed expansion in the total number of genes in this species was mainly caused by tandem duplications within subclade V, which accounts for 68% of the whole family. Comparative phylogenetic analyses showed that the expansion of subclade V is specifically observed for the Paniceae tribe within the Panicoideae subfamily in grasses. Five SvLAC genes (SvLAC9, SvLAC13, SvLAC15, SvLAC50, and SvLAC52) fulfilled the criteria established to identify lignin-related candidates: (1) phylogenetic proximity to previously characterized lignin-related laccases from other species, (2) similar expression pattern to that observed for lignin biosynthetic genes in the S. viridis elongating internode, and (3) high expression in S. viridis tissues undergoing active lignification. In addition, in situ hybridization experiments not only confirmed that these selected SvLAC genes were expressed in lignifying cells, but also that their expression showed different tissue specificities, suggesting subfunctionalization events within the family. These five laccase genes are strong candidates to be involved in lignin polymerization in S. viridis and might be good targets for lignin bioengineering strategies.

    更新日期:2020-01-09
  • Morphological and physiological responses of the potato stem transport tissues to dehydration stress
    Planta (IF 3.060) Pub Date : 2020-01-08
    Ernest B. Aliche, Alena Prusova-Bourke, Mariam Ruiz-Sanchez, Marian Oortwijn, Edo Gerkema, Henk Van As, Richard G. F. Visser, C. Gerard van der Linden

    Adaptation of the xylem under dehydration to smaller sized vessels and the increase in xylem density per stem area facilitate water transport during water-limiting conditions, and this has implications for assimilate transport during drought.

    更新日期:2020-01-08
  • Elucidating the regulatory roles of microRNAs in maize ( Zea mays L.) leaf growth response to chilling stress
    Planta (IF 3.060) Pub Date : 2020-01-06
    Fatma Aydinoglu

    miRNAs control leaf size of maize crop during chilling stress tolerance by regulating developmentally important transcriptional factors and sustaining redox homeostasis of cells.

    更新日期:2020-01-06
  • Characterization of Sicilian rosemary ( Rosmarinus officinalis L.) germplasm through a multidisciplinary approach
    Planta (IF 3.060) Pub Date : 2020-01-06
    Alessandra Carrubba, Loredana Abbate, Mauro Sarno, Francesco Sunseri, Antonio Mauceri, Antonio Lupini, Francesco Mercati

    Abstract In Sicily, small differences exist between wild and cultivated rosemary biotypes; VOCs and genetic profiles may be a useful tool to distinguish them. A germplasm collection of Rosmarinus officinalis L. was harvested from 15 locations in Sicily. Eleven wild and four cultivated populations were collected and, due to the surveyed area covered, they can be considered as a representative panel of Sicilian genetic background of the species. Ex situ plant collection was transferred to the field cultivation in homogeneous conditions for characterizing through a multidisciplinary approach. The study included morphological traits observations (growth habitus, flower color, number and size of leaves, length and number of internodes), VOC profiles using HS-SPME, genome size by flow cytometry analysis, and genetic characterization by means of DNA and nuclear microsatellite (nSSR) investigation. To detect any pattern within- and among-populations variability, all morphological and chemical data were submitted to ANOVA, while clustering and structure population analysis were carried out using genetic profiles. The present work allowed us to distinguish rather well between wild and cultivated genotypes and to underline the biodiversity richness among rosemary Sicilian germplasm, never highlighted, useful for future breeding programs addressed to exploit this important resource.

    更新日期:2020-01-06
  • Hydrogen sulfide acts downstream of jasmonic acid to inhibit stomatal development in Arabidopsis
    Planta (IF 3.060) Pub Date : 2020-01-06
    Guobin Deng, Lijuan Zhou, Yanyan Wang, Gensong Zhang, Xiaolan Chen

    Abstract Main conclusion: Jasmonic acid (JA) negatively regulates stomatal development by promoting LCD expression and hydrogen sulfide (H2S) biosynthesis. H2S inhibits the initiation of stomata formation and acts upstream of SPEECHLESS. Abstract: Stomatal development is strictly regulated by endogenous signals and environmental cues. We recently revealed that jasmonic acid (JA) negatively regulates stomatal development in Arabidopsis thaliana cotyledons (Han et al., Plant Physiol 176:2871–2885, 2018), but the underlying molecular mechanism remains largely unknown. Here, we uncovered a role for H2S in regulating stomatal development. The H2S scavenger hypotaurine reversed the JA-induced repression of stomatal development in the epidermis of wild-type Arabidopsis. The H2S-deficient mutant lcd displayed increased stomatal density and stomatal index values, which were rescued by treatment with sodium hydrosulfide (NaHS; an H2S donor) but not JA, suggesting that JA-mediated repression of stomatal development is dependent on H2S biosynthesis. The high stomatal density of JA-deficient mutants was rescued by exogenous NaHS treatment. Further analysis indicated that JA positively regulates LCD expression, l-cysteine desulfhydrases (l-CDes) activity, and endogenous H2S content. Furthermore, H2S represses the expression of stomate-associated genes and functions downstream of stomate-related signaling pathway components TOO MANY MOUTHS (TMM) and STOMATAL DENSITY AND DISTRIBUTION1 (SDD1) and upstream of SPEECHLESS (SPCH). Therefore, H2S acts downstream of JA signaling to regulate stomatal development in Arabidopsis cotyledons.

    更新日期:2020-01-06
  • Identification of two oxygenase genes involved in the respective biosynthetic pathways of canonical and non-canonical strigolactones in Lotus japonicus
    Planta (IF 3.060) Pub Date : 2020-01-06
    Narumi Mori, Takahito Nomura, Kohki Akiyama

    Abstract Main conclusion A cytochrome P450 and a 2-oxoglutarate-dependent dioxygenase genes responsible, respectively, for the biosyntheses of canonical and non-canonical strigolactones in Lotus japonicus were identified by transcriptome profiling and mutant screening. Abstract Strigolactones (SLs) are a group of apocarotenoids with diverse structures that act as phytohormones and rhizosphere signals. The model legume Lotus japonicus produces both canonical and non-canonical SLs, 5-deoxystrigol (5DS) and lotuslactone (LL), respectively, through oxidation of a common intermediate carlactone by the cytochrome P450 (CYP) enzyme MAX1. However, the pathways downstream of MAX1 and the branching point in the biosyntheses of 5DS and LL have not been elucidated. Here, we identified a CYP and a 2-oxoglutarate-dependent dioxygenase (2OGD) genes responsible, respectively, for the formation of Lotus SLs by transcriptome profiling using RNA-seq and screening of SL-deficient mutants from the Lotus retrotransposon 1 (LORE1) insertion mutant resource. The CYP and 2OGD genes were named DSD and LLD, respectively, after 5DS or LL defective phenotype of the mutants. The involvements of the genes in Lotus SL biosyntheses were confirmed by restoration of the mutant phenotype using Agrobacterium rhizogenes-mediated transformation to generate transgenic roots expressing the coding sequence. The transcript levels of DSD and LLD in roots as well as the levels of 5DS and LL in root exudates were reduced by phosphate fertilization and gibberellin treatment. This study can provide the opportunity to investigate how and why plants produce the two classes of SLs.

    更新日期:2020-01-06
  • Important roles of glycinebetaine in stabilizing the structure and function of the photosystem II complex under abiotic stresses
    Planta (IF 3.060) Pub Date : 2020-01-06
    Shan Huang, Ting Zuo, Wuzhong Ni

    The molecular and physiological mechanisms of glycinebetaine stabilizing photosystem II complex under abiotic stresses are discussed, helping to address food shortage problems threatening the survival of growing population.

    更新日期:2020-01-06
  • Systematic identification of genes associated with plant growth–defense tradeoffs under JA signaling in Arabidopsis
    Planta (IF 3.060) Pub Date : 2020-01-06
    Nailou Zhang, Bin Zhao, Zhijin Fan, Dongyan Yang, Xiaofeng Guo, Qifan Wu, Bin Yu, Shuang Zhou, Haiying Wang

    Abstract Main conclusion Co-expression and regulatory networks yield important insights into the growth–defense tradeoffs mechanism under jasmonic acid (JA) signals in Arabidopsis. Abstract Elevated defense is commonly associated with growth inhibition. However, a comprehensive atlas of the genes associated with the plant growth–defense tradeoffs under JA signaling is lacking. To gain an insight into the dynamic architecture of growth–defense tradeoffs, a coexpression network analysis was employed on publicly available high-resolution transcriptomes of Arabidopsis treated with coronatine (COR), a mimic of jasmonoyl-l-isoleucine. The genes involved in JA-mediated growth–defense tradeoffs were systematically revealed. Promoter enrichment analysis revealed the core regulatory module in which the genes underwent rapid activation, sustained upregulation after COR treatment, and mediated the growth–defense tradeoffs. Several transcription factors (TFs), including RAP2.6L, MYB44, WRKY40, and WRKY18, were identified as instantly activated components associated with pathogen and insect resistance. JA might rapidly activate RAV1 and KAN1 to repress brassinosteroid (BR) response genes, upregulate KAN1, the C2H2 TF families ZF2, ZF3, ZAT6, and STZ/ZAT10 to repress the biosynthesis, transport, and signaling of auxin to arrest growth. Independent datasets and preserved analyses validated the reproducibility of the results. Our study provided a comprehensive snapshot of genes that respond to JA signals and provided valuable resources for functional studies on the genetic modification of breeding population that exhibit robust growth and defense simultaneously.

    更新日期:2020-01-06
  • Cloning and functional characterization of a floral repressor gene from Lavandula angustifolia
    Planta (IF 3.060) Pub Date : 2020-01-06
    Rebecca S. Wells, Ayelign M. Adal, Lina Bauer, Elaheh Najafianashrafi, Soheil S. Mahmoud

    Abstract Main conclusion Using RNA-Seq, we identified genes involved in floral development in lavenders and functionally characterized the floral repressor LaSVP. Abstract The molecular aspects of flower initiation and development have not been adequately investigated in lavender (Lavandula). In order to identify genes that control these processes, we employed RNA-Seq to obtain sequence information for transcripts originating from the vegetative shoot apical meristem (SAM) and developing inflorescence tissues of Lavandula angustifolia and Lavandula × intermedia plants, and assemble a comprehensive transcriptome of 105,294 contigs. Homology-based annotation provided gene ontology terms for the majority of transcripts, including over 100 genes homologous to those that control flower initiation and organ identity in Arabidopsis thaliana. Expression analysis revealed that most of these genes are differentially expressed during flower development. For example, LaSVP, a homolog of the floral repressor SHORT VEGETATIVE PHASE (SVP), was strongly expressed in vegetative SAM compared to developing flowers, implicating its potential involvement in flowering repression in lavender. To investigate LaSVP further, we constitutively expressed the gene in transformed A. thaliana plants, evaluating its effects on flower initiation and morphology. Expression of the LaSVP in A. thaliana delayed flowering and affected flower organ identity in a dosage-dependent manner. Two of the highest expressing lines produced sepals instead of petals and were sterile as they failed to develop proper seed pods. This study provides the foundation for future investigations aimed at elucidating flower initiation and development in lavender.

    更新日期:2020-01-06
  • MicroRNA-mediated responses to colchicine treatment in barley
    Planta (IF 3.060) Pub Date : 2020-01-06
    Fang-Yao Sun, Lin Liu, Yi Yu, Xin-Ming Ruan, Cheng-Yu Wang, Qun-Wen Hu, De-Xiang Wu, Genlou Sun

    Abstract Main conclusion In Hordeum vulgare, nine differentially expressed novel miRNAs were induced by colchicine. Five novel miRNA in colchicine solution showed the opposite expression patterns as those in water. Abstract Colchicine is a commonly used agent for plant chromosome set doubling. MicroRNA-mediated responses to colchicine treatment in plants have not been characterized. Here, we characterized new microRNAs induced by colchicine treatment in Hordeum vulgare using high-throughput sequencing. Our results showed that 39 differentially expressed miRNAs were affected by water treatment, including 34 novel miRNAs and 5 known miRNAs; 42 miRNAs, including 37 novel miRNAs and 5 known miRNAs, were synergistically affected by colchicine and water, and 9 differentially expressed novel miRNAs were induced by colchicine. The novel_mir69, novel_mir57, novel_mir75, novel_mir38, and novel_mir56 in colchicine treatment showed the opposite expression patterns as those in water. By analyzing these 9 differentially expressed novel miRNAs and their targets, we found that novel_mir69, novel_mir56 and novel_mir25 co-target the genes involving the DNA repair pathway. Based on our results, microRNA-target regulation network under colchicine treatment was proposed, which involves actin, cell cycle regulation, cell wall synthesis, and the regulation of oxidative stress. Overall, the results demonstrated the critical role of microRNAs mediated responses to colchicine treatment in plants.

    更新日期:2020-01-06
  • Genetic dissection of yield-related traits via genome-wide association analysis across multiple environments in wild soybean ( Glycine soja Sieb. and Zucc.)
    Planta (IF 3.060) Pub Date : 2020-01-06
    Dezhou Hu, Huairen Zhang, Qing Du, Zhenbin Hu, Zhongyi Yang, Xiao Li, Jiao Wang, Fang Huang, Deyue Yu, Hui Wang, Guizhen Kan

    Abstract Main conclusion A total of 41 SNPs were identified as significantly associated with five yield-related traits in wild soybean populations across multiple environments, and the candidate gene GsCID1 was found to be associated with seed weight. These results may facilitate improvements in cultivated soybean. Abstract Crop-related wild species contain new sources of genetic diversity for crop improvement. Wild soybean (Glycine soja Sieb. and Zucc.) is the progenitor of cultivated soybean [Glycine max (L.) Merr.] and can be used as an essential genetic resource for yield improvements. In this research, using genome-wide association study (GWAS) in 96 out of 113 wild soybean accessions with 114,090 single nucleotide polymorphisms (SNPs) (with minor allele frequencies ≤ 0.05), SNPs associated with five yield-related traits were identified across multiple environments. In total, 41 SNPs were significantly associated with the traits in two or more environments (significance threshold P ≤ 8.76 × 10–6), with 29, 7, 3, and 2 SNPs detected for 100-seed weight (SW), maturity time (MT), seed yield per plant (SY) and flowering time (FT), respectively. BLAST search against the Glycine soja W05 reference genome was performed, 20 candidate genes were identified based on these 41 significant SNPs. One candidate gene, GsCID1 (Glysoja.04g010563), harbored two significant SNPs—AX-93713187, with a non-synonymous mutation, and AX-93713188, with a synonymous mutation. GsCID1 was highly expressed during seed development based on public information resources. The polymorphisms in this gene were associated with SW. We developed a derived cleaved amplified polymorphic sequence (dCAPS) marker for GsCID1 that was highly associated with SW and was validated as a functional marker. In summary, the revealed SNPs/genes are useful for understanding the genetic architecture of yield-related traits in wild soybean, which could be used as a potential exotic resource to improve cultivated soybean yields.

    更新日期:2020-01-06
  • Regulation of color transition in purple tea ( Camellia sinensis )
    Planta (IF 3.060) Pub Date : 2019-12-18
    Manglesh Kumari, Shweta Thakur, Ajay Kumar, Robin Joshi, Prakash Kumar, Ravi Shankar, Rajiv Kumar

    Comparative proteomics and metabolomics study of juvenile green, light purple and dark purple leaf to identify key proteins and metabolites that putatively govern color transition in Camellia sinensis.

    更新日期:2019-12-19
  • Transcriptional, metabolic and DNA methylation changes underpinning the response of Arundo donax ecotypes to NaCl excess
    Planta (IF 3.060) Pub Date : 2019-12-17
    Teresa Docimo, Rosalba De Stefano, Monica De Palma, Elisa Cappetta, Clizia Villano, Riccardo Aversano, Marina Tucci

    Arundo donax ecotypes react differently to salinity, partly due to differences in constitutive defences and methylome plasticity.

    更新日期:2019-12-18
  • The Arabidopsis cryptochrome 2 I404F mutant is hypersensitive and shows flavin reduction even in the absence of light
    Planta (IF 3.060) Pub Date : 2019-12-12
    Galileo Estopare Araguirang, Nils Niemann, Stephan Kiontke, Maike Eckel, Maribel L. Dionisio-Sese, Alfred Batschauer

    The cryptochrome photoreceptor mutant cry2I404F exhibits hyperactivity in the dark, hypersensitivity in different light conditions, and in contrast to the wild-type protein, its flavin chromophore is reducible even in the absence of light.

    更新日期:2019-12-13
  • Heterologous expression of an acid phosphatase gene and phosphate limitation leads to substantial production of chicoric acid in Echinacea purpurea transgenic hairy roots
    Planta (IF 3.060) Pub Date : 2019-12-10
    Meisam Salmanzadeh, Mohammad Sadegh Sabet, Ahmad Moieni, Mehdi Homaee

    A high level of the secondary metabolite chicoric acid is produced by intracellular Pi supply and extracellular phosphate limiting in Echinacea purpurea hairy roots.

    更新日期:2019-12-11
  • Inferring RPW8-NLRs’s evolution patterns in seed plants: case study in Vitis vinifera
    Planta (IF 3.060) Pub Date : 2019-12-10
    Giuseppe Andolfo, Clizia Villano, Angela Errico, Luigi Frusciante, Domenico Carputo, Riccardo Aversano, Maria R. Ercolano

    Genomic and transcriptomic studies in plants and, more in deep, in grapevine reveal that the disease-resistance RNL gene family is highly variable.

    更新日期:2019-12-11
  • DNA content equivalence in haploid and diploid maize leaves
    Planta (IF 3.060) Pub Date : 2019-12-09
    D. Santeramo, J. Howell, Y. Ji, W. Yu, W. Liu, T. Kelliher

    The qPCR assay developed to differentiate haploid and diploid maize leaf samples was unsuccessful due to DNA content difference. Haploid cells are packed more closely together with less cellular expansion.

    更新日期:2019-12-09
  • Mesocotyl elongation, an essential trait for dry-seeded rice ( Oryza sativa L.): a review of physiological and genetic basis
    Planta (IF 3.060) Pub Date : 2019-12-04
    Junhui Zhan, Xiang Lu, Hongyan Liu, Quanzhi Zhao, Guoyou Ye

    (1) Mesocotyl elongation is responsive to abiotic stresses, such as deep sowing drought, submergence, chilling, and salinity. (2) Humus soil culture with a burial depth of 6 cm and at the temperature of 30 °C could be the optimum method for mesocotyl length phenotyping, The frequently colocalized quantitative trait loci (QTL) controlling mesocotyl elongation were located on chromosome (3) 1 (RM562-RG146), chromosome 2 (RZ288-RM145), and chromosome 3 (RM426-RM520).

    更新日期:2019-12-04
  • Biochemical analysis of a new sugary-type rice mutant, Hemisugary1, carrying a novel allele of the sugary - 1 gene
    Planta (IF 3.060) Pub Date : 2019-12-04
    Sumire Takahashi, Yu Kumagai, Hidenari Igarashi, Karin Horimai, Hiroyuki Ito, Toru Shimada, Yoji Kato, Shigeki Hamada

    A novel allele of the sugary-1 rice mutant was isolated. The single amino acid change led to isoamylase activity reduction and accumulation of high-molecular-weight phytoglycogen in seeds.

    更新日期:2019-12-04
  • High-throughput metabolomic and transcriptomic analyses vet the potential route of cerpegin biosynthesis in two varieties of Ceropegia bulbosa Roxb.
    Planta (IF 3.060) Pub Date : 2019-12-04
    Sachin A. Gharat, Balkrishna A. Shinde, Ravindra D. Mule, Sachin A. Punekar, Bhushan B. Dholakia, Ramesha H. Jayaramaiah, Gopalakrishna Ramaswamy, Ashok P. Giri

    Exploration with high-throughput transcriptomics and metabolomics of two varieties of Ceropegia bulbosa identifies candidate genes, crucial metabolites and a potential cerpegin biosynthetic pathway.

    更新日期:2019-12-04
  • Silencing of class I small heat shock proteins affects seed-related attributes and thermotolerance in rice seedlings
    Planta (IF 3.060) Pub Date : 2019-12-03
    Neelam K. Sarkar, Sachin Kotak, Manu Agarwal, Yeon-Ki Kim, Anil Grover

    Silencing of CI-sHsps by RNAi negatively affected the seed germination process and heat stress response of rice seedlings. Seed size of RNAiCI-sHsp was reduced as compared to wild-type plants.

    更新日期:2019-12-04
  • Suppression of the maize phytoglobin ZmPgb1.1 promotes plant tolerance against Clavibacter nebraskensis
    Planta (IF 3.060) Pub Date : 2019-08-27
    V. Owusu, M. Mira, A. Soliman, L. R. Adam, F. Daayf, R. D. Hill, C. Stasolla

    Suppression of the maize phytoglobin ZmPgb1.1 enhances tolerance against Clavibacter nebraskensis by promoting hypersensitive response mechanisms mediated by ethylene and reactive oxygen species.

    更新日期:2019-11-13
  • Photobiont-dependent humidity threshold for chlorolichen photosystem II activation
    Planta (IF 3.060) Pub Date : 2019-09-21
    Nathan H. Phinney, Knut Asbjørn Solhaug, Yngvar Gauslaa

    Photobiont type influences the relative humidity threshold at which photosystem II activates in green algal lichens.

    更新日期:2019-11-13
  • Whole-genome DNA methylation patterns and complex associations with gene expression associated with anthocyanin biosynthesis in apple fruit skin
    Planta (IF 3.060) Pub Date : 2019-08-30
    Wen-Fang Li, Gai-Xing Ning, Juan Mao, Zhi-Gang Guo, Qi Zhou, Bai-Hong Chen

    DNA methylation of anthocyanin biosynthesis-related genes and MYB/bHLH transcription factors was associated with apple fruit skin color revealed by whole-genome bisulfite sequencing.

    更新日期:2019-11-13
  • Analysis of the MIR160 gene family and the role of MIR160a_A05 in regulating fiber length in cotton
    Planta (IF 3.060) Pub Date : 2019-10-16
    Guoyuan Liu, Ji Liu, Wenfeng Pei, Xihua Li, Nuohan Wang, Jianjiang Ma, Xinshan Zang, Jinfa Zhang, Shuxun Yu, Man Wu, Jiwen Yu

    The MIR160 family in Gossypium hirsutum and G. barbadense was characterized, and miR160a_A05 was found to increase cotton-fiber length by downregulating its target gene (ARF17) and several GH3 genes.

    更新日期:2019-11-13
  • Knockdown of CaHSP60 - 6 confers enhanced sensitivity to heat stress in pepper ( Capsicum annuum L.)
    Planta (IF 3.060) Pub Date : 2019-10-12
    Saeed ul Haq, Abid Khan, Muhammad Ali, Wen-Xian Gai, Huai-Xia Zhang, Qing-Hui Yu, Sheng-Bao Yang, Ai-Min Wei, Zhen-Hui Gong

    HSP60 gene family in pepper was analyzed through bioinformatics along with transcriptional regulation against multiple abiotic and hormonal stresses. Furthermore, the knockdown of CaHSP60-6 increased sensitivity to heat stress.

    更新日期:2019-11-13
  • Evolutionary convergence or homology? Comparative cytogenomics of Caesalpinia group species (Leguminosae) reveals diversification in the pericentromeric heterochromatic composition
    Planta (IF 3.060) Pub Date : 2019-11-06
    Brena Van-Lume, Yennifer Mata-Sucre, Mariana Báez, Tiago Ribeiro, Bruno Huettel, Edeline Gagnon, Ilia J. Leitch, Andrea Pedrosa-Harand, Gwilym P. Lewis, Gustavo Souza

    We demonstrated by cytogenomic analysis that the proximal heterochromatin of the Northeast Brazilian species of Caesalpinia group is enriched with phylogenetically conserved Ty3/Gypsy-Tekay RT, but diverge in the presence of Ty3/Gypsy-Athila RT and satDNA.

    更新日期:2019-11-06
  • Correction to: Two novel methylesterases from Olea europaea contribute to the catabolism of oleoside-type secoiridoid esters
    Planta (IF 3.060) Pub Date : 2019-11-01
    Jascha Volk, Alla Sarafeddinov, Turgay Unver, Stefan Marx, Joachim Tretzel, Jens Zotzel, Heribert Warzecha

    Page 5, paragraph 3, line 14, GenBank Accession Number which should read MK234850 instead of MK23485.

    更新日期:2019-11-01
  • Nectar- and stigma exudate-specific expression of an acidic chitinase could partially protect certain apple cultivars against fire blight disease.
    Planta (IF 3.060) Pub Date : 2019-11-30
    Anita Kurilla,Timea Toth,Laszlo Dorgai,Zsuzsanna Darula,Tamas Lakatos,Daniel Silhavy,Zoltan Kerenyi,Geza Dallmann

    Certain apple cultivars accumulate to high levels in their nectar and stigma exudate an acidic chitinase III protein that can protect against pathogens including fire blight disease causing Erwinia amylovora. To prevent microbial infections, flower nectars and stigma exudates contain various antimicrobial compounds. Erwinia amylovora, the causing bacterium of the devastating fire blight apple disease, is the model pathogen that multiplies in flower secretions and infects through the nectaries. Although Erwinia-resistant apples are not available, certain cultivars are tolerant. It was reported that in flower infection assay, the 'Freedom' cultivar was Erwinia tolerant, while the 'Jonagold' cultivar was susceptible. We hypothesized that differences in the nectar protein compositions lead to different susceptibility. Indeed, we found that an acidic chitinase III protein (Machi3-1) selectively accumulates to very high levels in the nectar and the stigma exudate of the 'Freedom' cultivar. We show that three different Machi3-1 alleles exist in apple cultivars and that only the 5B-Machi3-1 allele expresses the Machi3-1 protein in the nectar and the stigma exudate. We demonstrate that the 5B-Machi3-1 allele was introgressed from the Malus floribunda 821 clone into different apple cultivars including the 'Freedom'. Our data suggest that MYB-binding site containing repeats of the 5B-Machi3-1 promoter is responsible for the strong nectar- and stigma exudate-specific expression. As we found that in vitro, the Machi3-1 protein impairs growth and biofilm formation of Erwinia at physiological concentration, we propose that the Machi3-1 protein could partially protect 5B-Machi3-1 allele containing cultivars against Erwinia by inhibiting the multiplication and biofilm formation of the pathogen in the stigma exudate and in the nectar.

    更新日期:2019-11-01
  • Comprehensive transcriptome analysis of faba bean in response to vernalization.
    Planta (IF 3.060) Pub Date : 2019-11-30
    Bei Gao,Xiao-Chun Bian,Feng Yang,Mo-Xian Chen,Debatosh Das,Xiu-Ru Zhu,Yong Jiang,Jianhua Zhang,Yun-Ying Cao,Chun-Fang Wu

    This study unravels the transcriptional response of a highly productive faba bean cultivar under vernalization treatment. Faba bean (Vicia faba L.) is a member of the Leguminosae family and an important food crop worldwide providing valuable nutrients for humans. However, genome-wide studies and comprehensive sequencing resources of faba bean remain limited. Vernalization is crucial for enhanced yields in a number of winter-sown crops. However, the effects of vernalization on faba bean remain unknown. In this study, we generated a high-quality transcriptome assembly and functional annotation source for vernalized faba bean (Vicia faba L.) cv. Tongxian-2, a domesticated cultivar from southern China. A total of 369.9 million clean Illumina paired-end RNA-Seq reads were generated, and the transcriptome was assembled into 68,683 unigene sequences, with an average length of 1018 bp and an N50 of 1652 bp. Comprehensive functional annotation provided putative functional descriptions for more than 70% of the faba bean transcripts. We annotated a total of 1560 faba bean transcripts encoding transcription factors (TFs) belonging to 55 distinct TF families. The bHLH (168 transcripts), ERF (123 transcripts) and WRKY (105 transcripts) contained the largest number of TFs in response to vernalization. Genome-wide transcript changes comparing vernalized and unvernalized seedlings were investigated using bioinformatics approaches, which revealed a strong repression of photosynthesis and carbon metabolism, while genes participating in 'response to stress' were significantly induced. We also specifically identified vernalization-induced twenty-two 'pollen-pistil interaction' genes. A detailed functional annotation and expression profile analyses unveiled a number of protein kinases, which were specifically induced in vernalized seedlings. We also identified a total of 6852 simple sequence repeats (SSRs) in 6552 transcripts, representing a valuable genomic molecular marker resource for faba bean. In summary, this study provides new insights into the vernalization process in this economically valuable crop. The transcriptome data obtained provides us with a valuable candidate gene resource for future functional and molecular breeding studies. These data will contribute to the genome annotation for ensuing genome projects.

    更新日期:2019-11-01
  • Evidence that tolerance of Eutrema salsugineum to low phosphate conditions is hard-wired by constitutive metabolic and root-associated adaptations.
    Planta (IF 3.060) Pub Date : 2019-11-30
    Vera Marjorie Elauria Velasco,Solmaz Irani,Anna Axakova,Rosa da Silva,Peter S Summers,Elizabeth A Weretilnyk

    The extremophyte Eutrema salsugineum (Yukon ecotype) has adapted to an environment low in available phosphate through metabolic and root-associated traits that enables it to efficiently retrieve, use, and recycle phosphorus. Efficient phosphate (Pi) use by plants would increase crop productivity under Pi-limiting conditions and reduce our reliance on Pi applied as fertilizer. An ecotype of Eutrema salsugineum originating from the Yukon, Canada, shows no evidence of decreased relative growth rate or biomass under low Pi conditions and, as such, offers a promising model for identifying mechanisms to improve Pi use by crops. We evaluated traits associated with efficient Pi use by Eutrema (Yukon ecotype) seedlings and 4-week-old plants, including acquisition, remobilization, and the operation of metabolic bypasses. Relative to Arabidopsis, Eutrema was slower to remobilize phosphorus (P) from senescing leaves, primary and lateral roots showed a lower capacity for rhizosphere acidification, and root acid phosphatase activity was more broadly distributed and not Pi responsive. Both species produced long root hairs on low Pi media, whereas Arabidopsis root hairs were well endowed with phosphatase activity. This capacity was largely absent in Eutrema. In contrast to Arabidopsis, maximal in vitro rates of pyrophosphate-dependent phosphofructokinase and phosphoenolpyruvate carboxylase activities were not responsive to low Pi conditions suggesting that Eutrema has a constitutive and likely preferential capacity to use glycolytic bypass enzymes. Rhizosphere acidification, exudation of acid phosphatases, and rapid remobilization of leaf P are unlikely strategies used by Eutrema for coping with low Pi. Rather, equipping an entire root system for Pi acquisition and utilizing a metabolic strategy suited to deficient Pi conditions offer better explanations for how Eutrema has adapted to thrive on alkaline, highly saline soil that is naturally low in available Pi.

    更新日期:2019-11-01
  • Target of rapamycin signaling is tightly and differently regulated in the plant response under distinct abiotic stresses.
    Planta (IF 3.060) Pub Date : 2019-11-30
    Cintia M Pereyra,Néstor R Aznar,Marianela S Rodriguez,Graciela L Salerno,Giselle M A Martínez-Noël

    TOR signaling is finely regulated under diverse abiotic stresses and may be required for the plant response with a different time-course depending on the duration and nature of the stress. Target of rapamycin (TOR) signaling is a central regulator of growth and development in eukaryotic organisms. However, its regulation under stress conditions has not yet been elucidated. In Arabidopsis, we show that TOR transcripts and activity in planta are finely regulated within hours after the onset of salt, osmotic, cold and oxidative stress. The expression of genes encoding the partner proteins of the TOR complex, RAPTOR3G and LST8-1, is also regulated. Besides, the data indicate that TOR activity increases at some time during the adverse condition. Interestingly, in oxidative stress, the major TOR activity increment occurred transiently at the early phase of treatment, while in salt, osmotic and cold stress, it was around 1 day after the unfavorable condition was applied. Those results suggest that the TOR signaling has an important role in the plant response to an exposure to stress. Moreover, basal ROS (H2O2) levels and their modification under abiotic stresses were altered in TOR complex mutants. On the other hand, the root phenotypic analysis of the effects caused by the diverse abiotic stresses on TOR complex mutants revealed that they were differently affected, being in some cases less sensitive, than wild-type plants to long-term unfavorable conditions. Therefore, in this work, we demonstrated that TOR signaling is tightly regulated under abiotic stresses, at transcript and activity level, with different and specific time-course patterns according to the type of abiotic stress in Arabidopsis. Taking our results together, we propose that TOR signaling should be necessary during the plant stress response.

    更新日期:2019-11-01
  • In vitro characterization of root extracellular trap and exudates of three Sahelian woody plant species.
    Planta (IF 3.060) Pub Date : 2019-11-30
    Alexis Carreras,Sophie Bernard,Gaëlle Durambur,Bruno Gügi,Corinne Loutelier,Barbara Pawlak,Isabelle Boulogne,Maite Vicré,Azeddine Driouich,Deborah Goffner,Marie-Laure Follet-Gueye

    Arabinogalactan protein content in both root extracellular trap and root exudates varies in three Sahelian woody plant species that are differentially tolerant to drought. At the root tip, mature root cap cells, mainly border cells (BCs)/border-like cells (BLCs) and their associated mucilage, form a web-like structure known as the "Root Extracellular Trap" (RET). Although the RET along with the entire suite of root exudates are known to influence rhizosphere function, their features in woody species is poorly documented. Here, RET and root exudates were analyzed from three Sahelian woody species with contrasted sensitivity to drought stress (Balanites aegyptiaca, Acacia raddiana and Tamarindus indica) and that have been selected for reforestation along the African Great Green Wall in northern Senegal. Optical and transmission electron microscopy show that Balanites aegyptiaca, the most drought-tolerant species, produces only BC, whereas Acacia raddiana and Tamarindus indica release both BCs and BLCs. Biochemical analyses reveal that RET and root exudates of Balanites aegyptiaca and Acacia raddiana contain significantly more abundant arabinogalactan proteins (AGPs) compared to Tamarindus indica, the most drought-sensitive species. Root exudates of the three woody species also differentially impact the plant soil beneficial bacteria Azospirillum brasilense growth. These results highlight the importance of root secretions for woody species survival under dry conditions.

    更新日期:2019-11-01
  • Characterization of five CHASE-containing histidine kinase receptors from Populus × canadensis cv. Robusta sensing isoprenoid and aromatic cytokinins.
    Planta (IF 3.060) Pub Date : 2019-11-30
    Pavel Jaworek,Petr Tarkowski,Tomáš Hluska,Štěpán Kouřil,Ondřej Vrobel,Jaroslav Nisler,David Kopečný

    Five poplar CHASE-containing histidine kinase receptors bind cytokinins and display kinase activities. Both endogenous isoprenoid and aromatic cytokinins bind to the receptors in live cell assays. Cytokinins are phytohormones that play key roles in various developmental processes in plants. The poplar species Populus × canadensis, cv. Robusta, is the first organism found to contain aromatic cytokinins. Here, we report the functional characterization of five CHASE-containing histidine kinases from P. × canadensis: PcHK2, PcHK3a, PcHK3b, PcHK4a and PcHK4b. A qPCR analysis revealed high transcript levels of all PcHKs other than PcHK4b across multiple poplar organs. The ligand specificity was determined using a live cell Escherichia coli assay and we provide evidence based on UHPLC-MS/MS data that ribosides can be true ligands. PcHK2 exhibited higher sensitivity to iP-type cytokinins than the other receptors, while PcHK3a and PcHK3b bound these cytokinins much more weakly, because they possess two isoleucine residues that clash with the cytokinin base and destabilize its binding. All receptors display kinase activity but their activation ratios in the presence/absence of cytokinin differ significantly. PcHK4a displays over 400-fold higher kinase activity in the presence of cytokinin, suggesting involvement in strong responses to changes in cytokinin levels. trans-Zeatin was both the most abundant cytokinin in poplar and that with the highest variation in abundance, which is consistent with its strong binding to all five HKs and activation of cytokinin signaling via A-type response regulators. The aromatic cytokinins' biological significance remains unclear, their levels vary diurnally, seasonally, and annually. PcHK3 and PcHK4 display the strongest binding at pH 7.5 and 5.5, respectively, in line with their putative membrane localization in the endoplasmic reticulum and plasma membrane.

    更新日期:2019-11-01
  • A two-step mutation process in the double WS1 homologs drives the evolution of burley tobacco, a special chlorophyll-deficient mutant with abnormal chloroplast development.
    Planta (IF 3.060) Pub Date : 2019-11-30
    Xinru Wu,Daping Gong,Fei Xia,Changbo Dai,Xingwei Zhang,Xiaoming Gao,Shaomei Wang,Xu Qu,Yuhe Sun,Guanshan Liu

    The functional homologs WS1A and WS1B, identified by map-based cloning, control the burley character by affecting chloroplast development in tobacco, contributing to gene isolation and genetic improvement in polyploid crops. Burley represents a special type of tobacco (Nicotiana tabacum L.) cultivar that is characterized by a white stem with a high degree of chlorophyll deficiency. Although important progress in the research of burley tobacco has been made, the molecular mechanisms underlying this character remain unclear. Here, on the basis of our previous genetic analyses and preliminary mapping results, we isolated the White Stem 1A (WS1A) and WS1B genes using a map-based cloning approach. WS1A and WS1B are functional homologs with completely identical biological functions and highly similar expression patterns that control the burley character in tobacco. WS1A and WS1B are derived from Nicotiana sylvestris and Nicotiana tomentosiformis, the diploid ancestors of Nicotiana tabacum, respectively. The two genes encode zinc metalloproteases of the M50 family that are highly homologous to the Ethylene-dependent Gravitropism-deficient and Yellow-green 1 (EGY1) protein of Arabidopsis and the Lutescent 2 (L2) protein of tomato. Transmission electron microscopic examinations indicated that WS1A and WS1B are involved in the development of chloroplasts by controlling the formation of thylakoid membranes, very similar to that observed for EGY1 and L2. The genotyping of historical tobacco varieties revealed that a two-step mutation process occurred in WS1A and WS1B during the evolution of burley tobacco. We also discussed the strategy for gene map-based cloning in polyploid plants with complex genomes. This study will facilitate the identification of agronomically important genes in tobacco and other polyploid crops and provide insights into crop improvement via molecular approaches.

    更新日期:2019-11-01
  • Oxidation of polyphenols and inhibition of photosystem II under acute photooxidative stress.
    Planta (IF 3.060) Pub Date : 2019-11-30
    Guy Samson,Zoran G Cerovic,Waleed M A El Rouby,Pierre Millet

    We observed a close correlation between the inhibition of photosystem II and the oxidation of polyphenols during an acute oxidative stress in sunflower leaf discs. To assess the physiological significance of polyphenols as antioxidants in planta, we compared the kinetics of polyphenols oxidation with the inhibition of the photosynthetic apparatus in sunflower leaf discs exposed to an acute photooxidative stress. Illumination of leaf discs in the presence of methyl viologen induced a rapid and large non-photochemical quenching of chlorophyll-a fluorescence, which was reversed after 4 h of treatment as indicated by the ≈ 30% increases of the steady-state (Fs) and maximal (Fm') levels of chlorophyll-a fluorescence relative to the first hour of treatment. This event coincided with the accelerated decreases of the maximum (Fv/Fm) and effective (∆F/Fm') quantum yields of photosystem II, and also with the beginning of polyphenols oxidation, estimated by the UV absorbance of methanolic leaf extracts, and supported by the Folin-Ciocalteu method and cyclic voltammetry. The decreases of Fv/Fm and the concentrations of reducing polyphenols were highly correlated (R2 = 0.877) during the experiment. Coherent with the decrease of UV absorbance of methanolic extracts, polyphenol oxidation resulted in a marked decrease of UV absorbance of leaf epidermis. Also, polymerization of oxidized polyphenols caused the accumulation of brown pigments in the MV-treated leaf discs, decreasing leaf reflectance, especially at 550 and 740 nm. Fluorescence intensities were also decreased during the MV treatment. Interestingly, the emission fluorescence ratio F740/F684 (excitation at 550 nm) decreased similarly to Fv/Fm (R2 = 0.981) due to the brown pigments. Moreover, the excitation fluorescence ratio F484/F680 (emission at 740 nm) was linearly correlated (R2 = 0.957) to ∆F/Fm', indicating a decrease of efficiency of energy transfer between the antenna pigments to the photosystem II reaction center during the oxidative stress. These results support the view that polyphenols can be effective antioxidants protecting the plants against reactive oxygen species.

    更新日期:2019-11-01
  • Osmoprotection in plants under abiotic stresses: new insights into a classical phenomenon.
    Planta (IF 3.060) Pub Date : 2019-11-30
    Faisal Zulfiqar,Nudrat Aisha Akram,Muhammad Ashraf

    Plant osmoprotectants protect against abiotic stresses. Introgression of osmoprotectant genes into crop plants via genetic engineering is an important strategy in developing more productive plants. Plants employ adaptive mechanisms to survive various abiotic stresses. One mechanism, the osmoprotection system, utilizes various groups of low molecular weight compounds, collectively known as osmoprotectants, to mitigate the negative effect of abiotic stresses. Osmoprotectants may include amino acids, polyamines, quaternary ammonium compounds and sugars. These nontoxic compounds stabilize cellular structures and enzymes, act as metabolic signals, and scavenge reactive oxygen species produced under stressful conditions. The advent of recent drastic fluctuations in the global climate necessitates the development of plants better adapted to abiotic stresses. The introgression of genes related to osmoprotectant biosynthesis from one plant to another by genetic engineering is a unique strategy bypassing laborious conventional and classical breeding programs. Herein, we review recent literature related to osmoprotectants and transgenic plants engineered with specific osmoprotectant properties.

    更新日期:2019-11-01
  • Diverse transcription factors control monoterpene synthase expression in lavender (Lavandula).
    Planta (IF 3.060) Pub Date : 2019-11-30
    Lukman S Sarker,Ayelign M Adal,Soheil S Mahmoud

    We cloned eight transcription factors that activate lavender monoterpene synthase promoters. In this study, we employed the Yeast One-Hybrid (Y1H) assay system to identify transcription factors that control promoters for two Lavandula × intermedia monoterpene synthase genes, linalool synthase (LiLINS) and 1,8-cineole synthase (LiCINS). The bait sequences used in the assay were either a 768-bp LiLINS, or a 1087-bp LiCINS promoter. The prey included proteins expressed in L. × intermedia floral tissue. The assay identified 96 sequences encoding proteins that interacted with one or both promoters. To explore the nature of this interaction, the LiLINS and LiCINS promoter fragments were each fused to the E. coli gusA (GUS) reporter gene. The constructs were separately transformed into tobacco (Nicotiana benthamiana) leaves co-expressing individually a subset of ten representative transcription factors (TFs) predicted to control these promoters. Six TFs induced expression from both promoters, two activated LiCINS promoter alone, and two did not induce expression from either promoter. The TFs identified in this study belong to various groups including those containing conserved domains typical of MYB, bZIP, NAC, GeBP and SBP-related proteins.

    更新日期:2019-11-01
  • The cysteine-rich receptor-like protein kinase CRK28 modulates Arabidopsis growth and development and influences abscisic acid responses.
    Planta (IF 3.060) Pub Date : 2019-11-30
    Ramón Pelagio-Flores,Edith Muñoz-Parra,Salvador Barrera-Ortiz,Randy Ortiz-Castro,Jorge Saenz-Mata,María Azucena Ortega-Amaro,Juan Francisco Jiménez-Bremont,José López-Bucio

    CRK28, a cysteine-rich receptor-like kinase, plays a role in root organogenesis and overall growth of plants and antagonizes abscisic acid response in seed germination and primary root growth. Receptor-like kinases (RLK) orchestrate development and adaptation to environmental changes in plants. One of the largest RLK groups comprises cysteine-rich receptor-like kinases (CRKs), for which the function of most members remains unknown. In this report, we show that the loss of function of CRK28 led to the formation of roots that are longer and more branched than the parental (Col-0) plantlets, and this correlates with an enhanced domain of the mitotic reporter CycB1:uidA in primary root meristems, whereas CRK28 overexpressing lines had the opposite phenotype, including slow root growth and reduced lateral root formation. Epidermal cell analyses revealed that crk28 mutants had reduced root hair length and increased trichome number, whereas 35S::CRK28 lines present primary roots with longer root hairs but lesser trichomes in leaves. The overall growth in soil of crk28 mutant and CRK28 overexpressing lines was reduced or enhanced, respectively, when compared to the parental (Col-0) seedlings, while germination, root growth and expression analyses of ABI3 and ABI5 further showed that CRK28 modulates ABA responses, which may be important to fine-tune plant morphogenesis. Our study unravels the participation of RLK signaling in root growth and epidermal cell differentiation.

    更新日期:2019-11-01
  • Expression analysis and functional characterization of two PHT1 family phosphate transporters in ryegrass.
    Planta (IF 3.060) Pub Date : 2019-11-30
    Leyla Parra-Almuna,Sofía Pontigo,Giovanni Larama,Jonathan R Cumming,Jacob Pérez-Tienda,Nuria Ferrol,María de la Luz Mora

    The phosphate transporters LpPHT1;1 and LpPHT1;4 have different roles in phosphate uptake and translocation in ryegrass under P stress condition. The phosphate transporter 1 (PHT1) family are integral membrane proteins that operate in phosphate uptake, distribution and remobilization within plants. In this study, we report on the functional characterization and expression of two PHT1 family members from ryegrass plants (Lolium perenne L.) and determine their roles in the specificity of Pi transport. The expression level of LpPHT1;4 was strongly influenced by phosphorus (P) status, being higher under P-starvation condition. In contrast, the expression level of LpPHT1;1 was not correlated with P supply. Yeast mutant complementation assays showed that LpPHT1;4 can complement the growth defect of the yeast mutant Δpho84 under Pi-deficient conditions, whereas the yeast mutant expressing LpPHT1;1 was not able to restore growth. Phylogenetic and molecular analyses indicated high sequence similarity to previously identified PHT1s from other species in the Poaceae. These results suggest that LpPHT1;1 may function as a low-affinity Pi transporter, whereas LpPHT1;4 could acts as a high-affinity Pi transporter to maintain Pi homeostasis under stress conditions in ryegrass plants. This study will form the basis for the long-term goal of improving the phosphate use efficiency of ryegrass plants.

    更新日期:2019-11-01
  • Chalcone synthases (CHSs): the symbolic type III polyketide synthases.
    Planta (IF 3.060) Pub Date : 2019-11-30
    Shahzad A Pandith,Salika Ramazan,Mohd Ishfaq Khan,Zafar A Reshi,Manzoor A Shah

    Present review provides a thorough insight on some significant aspects of CHSs over a period of about past three decades with a better outlook for future studies toward comprehending the structural and mechanistic intricacy of this symbolic enzyme. Polyketide synthases (PKSs) form a large family of iteratively acting multifunctional proteins that are involved in the biosynthesis of spectrum of natural products. They exhibit remarkable versatility in the structural configuration and functional organization with an incredible ability to generate different classes of compounds other than the characteristic secondary metabolite constituents. Architecturally, chalcone synthase (CHS) is considered to be the simplest representative of Type III PKSs. The enzyme is pivotal for phenylpropanoid biosynthesis and is also well known for catalyzing the initial step of the flavonoid/isoflavonoid pathway. Being the first Type III enzyme to be discovered, CHS has been subjected to ample investigations which, to a greater extent, have tried to understand its structural complexity and promiscuous functional behavior. In this context, we vehemently tried to collect the fragmented information entirely focussed on this symbolic enzyme from about past three-four decades. The aim of this review is to selectively summarize data on some of the fundamental aspects of CHSs viz, its history and distribution, localization, structure and analogs in non-plant hosts, promoter analyses, and role in defense, with an emphasis on mechanistic studies in different species and vis-à-vis mutation-led changes, and evolutionary significance which has been discussed in detail. The present review gives an insight with a better perspective for the scientific community for future studies devoted towards delimiting the mechanistic and structural basis of polyketide biosynthetic machinery vis-à-vis CHS.

    更新日期:2019-11-01
  • Comparative proteomic analysis of resistant and susceptible potato cultivars during Synchytrium endobioticum infestation.
    Planta (IF 3.060) Pub Date : 2019-11-30
    Katarzyna Szajko,Jarosław Plich,Jarosław Przetakiewicz,Dorota Sołtys-Kalina,Waldemar Marczewski

    We report the first comparative study of protein expression profiles in tuber sprouts between Katahdin-derived potato cultivars resistant and susceptible to Synchytrium endobioticum. Synchytrium endobioticum causes wart disease in potato (Solanum tuberosum L.) and is considered as the most important quarantine pathogen in almost all countries where potatoes are grown. We performed a comparative analysis of differentially expressed proteins in the tuber sprouts of potato cultivars differing in resistance to pathotype 1(D1) of S. endobioticum using two-dimensional electrophoresis (2-DE) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) approaches. Bulks prepared from two resistant (Calrose and Humalda) and three susceptible (Sebago, Seneca and Wauseon) potato cultivars were studied. When protein profiles were compared between mock- and S. endobioticum-inoculated sprouts, 35 and 63 protein spots, indicating qualitative or quantitative differences, were detected in the resistant and susceptible cultivars, respectively. In turn, 24 proteins associated with resistance to S. endobioticum were revealed by comparison of the resistant and susceptible bulks. These proteins were changed in a constitutive or induced manner and were grouped into four categories: stress and defence, cell structure, protein turnover, and metabolism. Among the 13 proteins classified into the stress and defence group, seven proteins were related to heat-shock proteins (HSPs)/chaperone factors. In addition, four proteins, S-adenosyl-L-homocysteine hydrolase-like, superoxide dismutase [Mn], inactive patatin-3-Kuras 1 and patatin-15, were induced in the resistant bulk; whereas two proteins, patatin-01 and nucleoredoxin 1, showed significant differences in expression between the S. endobioticum-inoculated resistant and susceptible bulks. The detection of such a large number of S. endobioticum-mediated proteins representing the HSP70, HSP60 and HSP20 families suggests their significant role in restricting wart disease in potato tubers.

    更新日期:2019-11-01
  • Transgenic expression of Hyp-1 gene from Hypericum perforatum L. alters expression of defense-related genes and modulates recalcitrance to Agrobacterium tumefaciens.
    Planta (IF 3.060) Pub Date : 2019-11-30
    Weina Hou,Rupesh Kumar Singh,Pan Zhao,Viviana Martins,Emmanuel Aguilar,Tomás Canto,Francisco Tenllado,Alberto Carlos Pires Dias

    Phenolic oxidative coupling protein (Hyp-1) isolated from Hypericum perforatum L. was characterized as a defense gene involved in H. perforatum recalcitrance to Agrobacterium tumefaciens-mediated transformation Hypericum perforatum L. is a reservoir of high-value secondary metabolites of increasing interest to researchers and to the pharmaceutical industry. However, improving their production via genetic manipulation is a challenging task, as H. perforatum is recalcitrant to Agrobacterium tumefaciens-mediated transformation. Here, phenolic oxidative coupling protein (Hyp-1), a pathogenesis-related (PR) class 10 family gene, was selected from a subtractive cDNA library from A. tumefaciens-treated H. perforatum suspension cells. The role of Hyp-1 in defense against A. tumefaciens was analyzed in transgenic Nicotiana tabacum and Lactuca sativa overexpressing Hyp-1, and in Catharanthus roseus silenced for its homologous Hyp-1 gene, CrIPR. Results showed that Agrobacterium-mediated expression efficiency greatly decreased in Hyp-1 transgenic plants. However, silencing of CrIPR induced CrPR-5 expression and decreased expression efficiency of Agrobacterium. The expression of core genes involved in several defense pathways was also analyzed in Hyp-1 transgenic tobacco plants. Overexpression of Hyp-1 led to an ample down-regulation of key genes involved in auxin signaling, microRNA-based gene silencing, detoxification of reactive oxygen species, phenylpropanoid pathway and PRs. Moreover, Hyp-1 was detected in the nucleus, plasma membrane and the cytoplasm of epidermal cells by confocal microscopy. Overall, our findings suggest Hyp-1 modulates recalcitrance to A. tumefaciens-mediated transformation in H. perforatum.

    更新日期:2019-11-01
  • Site-dependent induction of jasmonic acid-associated chemical defenses against western flower thrips in Chrysanthemum.
    Planta (IF 3.060) Pub Date : 2019-11-30
    Gang Chen,Hye Kyong Kim,Peter Gl Klinkhamer,Rocío Escobar-Bravo

    Local and systemic induction of JA-associated chemical defenses and resistance to western flower thrips in Chrysanthemum are spatially variable and dependent on the site of the JA application. Plants have evolved numerous inducible defense traits to resist or tolerate herbivory, which can be activated locally at the site of the damage, or systemically through the whole plant. Here we investigated how activation of local and systemic chemical responses upon exogenous application of the phytohormone jasmonic acid (JA) varies along the plant canopy in Chrysanthemum, and how these responses correlate with resistance to thrips. Our results showed that JA application reduced thrips damage per plant when applied to all the plant leaves or when locally applied to apical leaves, but not when only basal leaves were locally treated. Local application of JA to apical leaves resulted in a strong reduction in thrips damage in new leaves developed after the JA application. Yet, activation of a JA-associated defensive protein marker, polyphenol oxidase, was only locally induced. Untargeted metabolomic analysis further showed that JA increased the concentrations of sugars, phenylpropanoids, flavonoids and some amino acids in locally induced basal and apical leaves. However, local application of JA to basal leaves marginally affected the metabolomic profiles of systemic non-treated apical leaves, and vice versa. Our results suggest that JA-mediated activation of systemic chemical defense responses is spatially variable and depends on the site of the application of the hormone in Chrysanthemum.

    更新日期:2019-11-01
  • Chromium effects on photosynthetic electron transport in pea (Pisum sativum L.).
    Planta (IF 3.060) Pub Date : 2019-11-30
    Daria Todorenko,Nyurgun Timofeev,Ilya Kovalenko,Galina Kukarskikh,Dmitry Matorin,Taras Antal

    Components of the photosynthetic electron transport chain in pea (Pisum sativum L.) leaves under in vivo conditions showed the following sensitivity to the inhibitory action of chromium(VI): intersystem electron transport > photosystem I > photosystem II. Inhibitory effects of chromium (VI) (K2Cr2O7, Cr) on the light reactions of photosynthesis were studied in vivo in Pisum sativum L. by using Multi-function Plant Efficiency Analyser (M-PEA-2). Photosynthetic parameters related to photosystem (PS) II, PSI and intersystem electron carriers were calculated from the light-induced kinetics of prompt chlorophyll a fluorescence (OJIP transient), delayed chlorophyll a fluorescence (DF), and 820 nm modulated reflection (MR). We showed that the I2 step of DF induction is sensitive to inhibition of the Q0 site of the cytochrome b6f complex. Such parameters as δRo of the JIP test related to the functional state of photosynthetic reactions beyond the PQ pool, Vred of the MR induction assigned to the overall rate of P700+ and plastocyanin reduction, and I2 step of the DF induction were significantly altered in the presence of low-dose Cr(VI). Moderate doses of Cr affected mainly PSI-related parameters including Vox and ΔMR parameters of the MR induction, whereas high-dose treatment influenced JIP test parameters φPo(= FV/FM) and ψEo related to PSII. The obtained results showed that the earliest Cr(VI) effect on the photosynthetic electron transport chain manifests itself by inhibition of the intersystem electron transport, rather, at the level of the cytochrome b6f complex. Inhibitory effects of Cr on PSI were more pronounced than those on PSII. Sensitivity of the used kinetic parameters toward the functional state of photosynthetic reactions makes this approach suitable for early diagnostics of toxic action of pollutants on plants.

    更新日期:2019-11-01
  • Phytochemistry and pharmacological activities of the genus Rhynchosia: a comprehensive review.
    Planta (IF 3.060) Pub Date : 2019-11-30
    Aluru Rammohan,Guda Mallikarjuna Reddy,Baki Vijaya Bhaskar,Duvvuru Gunasekar,Grigory V Zyryanov

    The genus Rhynchosia is a rich source of natural compounds especially flavonoids and prenylated isoflavonoids. Further experimental studies on Rhynchosia members may be result new and novel secondary metabolites with potent biological activities. Traditionally, medicinal plants have played a significant role on human life since ancient days. At present, natural compounds are the major source for the modern drug discovery owing to their therapeutic selectivity, minutest of side effects, inexpensive source and serve as lead molecules for the discovery of new drugs. Rhynchosia species (Fabaceae) are extensively circulated throughout the tropical and subtropical areas around the world. A few plants of this genus were used in traditional medicine for the treatment of various ailments such as antibacterial, antidiabetic, abortifacients, healing of wounds, hepatoprotective, remedial of boils, rheumatic pains and skin infections. The present review compiles traditional uses, isolated chemical compounds and pharmacological activities of Rhynchosia species. So far, in total, seventy-seven compounds were isolated from the genus Rhynchosia, including flavonoids, isoflavonoids, flavan-3-ols, xanthones, biphenyls, simple polyphenols and sterols. It is interesting to note that the genus Rhynchosia is a rich source of C-glycosylflavonoids and prenylated isoflavonoids. Further, phytochemical and pharmacological studies on this genus are required since only few species have been investigated so far.

    更新日期:2019-11-01
  • Alternative splicing is a Sorghum bicolor defense response to fungal infection.
    Planta (IF 3.060) Pub Date : 2019-11-30
    Lanxiang Wang,Moxian Chen,Fuyuan Zhu,Tao Fan,Jianhua Zhang,Clive Lo

    This study provides new insights that alternative splicing participates with transcriptional control in defense responses to Colletotrichum sublineola in sorghum In eukaryotic organisms, alternative splicing (AS) is an important post-transcriptional mechanism to generate multiple transcript isoforms from a single gene. Protein variants translated from splicing isoforms may have altered molecular characteristics in signal transduction and metabolic activities. However, which transcript isoforms will be translated into proteins and the biological functions of the resulting proteoforms are yet to be identified. Sorghum is one of the five major cereal crops, but its production is severely affected by fungal diseases. For example, sorghum anthracnose caused by Colletotrichum sublineola greatly reduces grain yield and biomass production. In this study, next-generation sequencing technology was used to analyze C. sublineola-inoculated sorghum seedlings compared with mock-inoculated control. It was identified that AS regulation may be as important as traditional transcriptional control during defense responses to fungal infection. Moreover, several genes involved in flavonoid and phenylpropanoid biosynthetic pathways were found to undergo multiple AS modifications. Further analysis demonstrated that non-conventional targets of both 5'- and 3'-splice sites were alternatively used in response to C. sublineola infection. Splicing factors were also affected at both transcriptional and post-transcriptional levels. As the first transcriptome report on C. sublineola infected sorghum, our work also suggested that AS plays crucial functions in defense responses to fungal invasion.

    更新日期:2019-11-01
  • Up-regulation of microRNA targets correlates with symptom severity in Citrus sinensis plants infected with two different isolates of citrus psorosis virus.
    Planta (IF 3.060) Pub Date : 2019-11-30
    Facundo E Marmisolle,Ailín Arizmendi,Andrés Ribone,Máximo Rivarola,María L García,Carina A Reyes

    MAIN CONCLUSION: miRNA targets from Citrus sinensis are predicted and validated using degradome data. They show an up-regulation upon infection with CPsV, with a positive correlation between target expression and symptom severity. Sweet orange (Citrus sinensis) may suffer from disease symptoms induced by virus infections, thus resulting in drastic economic losses. Infection of sweet orange plants with two isolates of citrus psorosis virus (CPsV), expressing different symptomatologies, alters the accumulation of a set of endogenous microRNAs (miRNAs). Here, we predicted ten putative targets from four down-regulated miRNAs: three belonging to the CCAAT-binding transcription factor family (CBFAs); an Ethylene-responsive transcription factor (RAP2-7); an Integrase-type DNA-binding superfamily protein (AP2B); Transport inhibitor response 1 (TIR1); GRR1-like protein 1-related (GRR1); Argonaute 2-related (AGO2), Argonaute 7 (AGO7), and a long non-coding RNA (ncRNA). We validated six of them through analysis of leaf degradome data. Expressions of the validated targets increase in infected samples compared to healthy tissue, showing a more striking up-regulation those samples with higher symptom severity. This study contributes to the understanding of the miRNA-mediated regulation of important transcripts in Citrus sinensis through target validation and shed light in the manner a virus can alter host regulatory mechanisms leading to symptom expression.

    更新日期:2019-11-01
  • Leaf vascular architecture in temperate dicotyledons: correlations and link to functional traits.
    Planta (IF 3.060) Pub Date : 2019-11-30
    Kiyosada Kawai,Naoki Okada

    Using 227 dicotyledonous species in temperate region, we found the relationships among densities of different-order veins, creating diversity of leaf vascular architectures. Dicotyledonous angiosperms commonly possess a hierarchical leaf vascular system, wherein veins of different orders have different functions. Minor vein spacing determines leaf hydraulic efficiency, whereas the major veins provide mechanical support. However, there is limited information on the coordination between these vein orders across species, limiting our understanding of how diversity in vein architecture is arrayed. We aimed to examine the (1) relationships between vein densities at two spatial scales (lower- vs. higher-order veins and among minor veins) and (2) relationships of vein densities with plant functional traits. We studied ten traits related to vein densities and three functional traits (leaf dry mass per area [LMA], leaf longevity [LL], and adult plant height [Hadult]) for 227 phylogenetically diverse plant species that occur in temperate regions and examined the vein-vein and vein-functional traits relationships across species. The densities of lower- and higher-order veins were positively correlated across species. The minor vein density was positively correlated with the densities of both areoles and free-ending veins, and vascular networks with higher minor vein density tended to have a lower ratio of free-ending veins to areoles across species. Neither densities of lower- nor higher-order veins were related to LMA and LL. On the other hand, the densities of veins and areoles tended to be positively correlated with Hadult. These results suggest that densities of different-order veins are developmentally coordinated across dicotyledonous angiosperms and form the independent axis in resource use strategies based on the leaf economics spectrum.

    更新日期:2019-11-01
  • Exosomes in the phloem and xylem of woody plants.
    Planta (IF 3.060) Pub Date : 2019-11-30
    Dmitry G Chukhchin,Ksenia Bolotova,Igor Sinelnikov,Dmitry Churilov,Evgeniy Novozhilov

    Exosomes in the secondary phloem and secondary xylem of angiosperms and gymnosperms have physiological roles in the storage and transport of endoglucanases. Knowledge of plant extracellular vesicles (EVs) is limited by their presence in the apoplastic fluid of seeds and leaves. The contents of plant EVs and their biological functions are unclear. The aim of the present study was to expand our knowledge of EVs in woody plants. Sample splits were prepared from branch and stem samples from angiosperms and gymnosperms after cryomechanical destruction with liquid nitrogen. The study methods included scanning electron (SEM), atomic force microscopy (AFM), endoglucanase activity measurement. EVs visualized on the internal layers of the cell walls proved to be exosomes according to their diameter (65-145 nm). SEM revealed cup-shaped structures characteristic of exosomes in a dry state. Plant exosomes in the form of globules in the native state were visualized for the first time by AFM. Exosomes were present both in the active and dormant cambium. Erosion zones were observed at the sites of exosome localization. The activity of endo-1,4-β-glucanase was detected in Picea xylem, while the RNA level was very low, suggesting that endo-1,4-β-glucanases were preserved in the exosomes. There are grounds to assert that endo-1,4-β-glucanases delivered by exosomes participated in pit cavity formation in the S1 layer of xylary fibres. A possible mechanism of endo-1,4-β-glucanase action in the biosynthesis of the secondary wall is proposed. These results demonstrate that the physiological role of the exosomes in the phloem and xylem is the storage and transport of endo-1,4-β-glucanases participating in cell wall remodeling in woody plants. Present study expands our knowledge about plant exosomes.

    更新日期:2019-11-01
  • Medicago truncatula root developmental changes by growth-promoting microbes isolated from Fabaceae, growing on organic farms, involve cell cycle changes and WOX5 gene expression.
    Planta (IF 3.060) Pub Date : null
    Ewa Kępczyńska,Piotr Karczyński

    Both root nodules and the rhizosphere of Fabaceae plants grown on organic farms are a rich source of bacteria, mainly from the families Enterobacteriaceae and Pseudomonadaceae. The enhanced root system growth in M. truncatula after inoculation with selected bacteria includes an increase of nuclei in the cell cycle S phase and a reduction in phase G2 as well as an enhanced expression of the WOX5 gene. Synthetic fertilizers and pesticides are commonly used to improve plant quality and health. However, it is necessary to look for other efficient and also environmentally safe methods. One such method involves the use of bacteria known as plant growth-promoting bacteria (PGPB). Seventy-two bacterial isolates from the rhizospheric soil and root nodule samples of legumes, including bean, alfalfa, lupine and barrel medic, grown on an organic farm in Western Pomerania (Poland) were screened for their growth-promoting capacities and 38 selected isolates were identified based on 16S rRNA gene sequencing. The analysis showed the isolates to represent 17 strains assigned to 6 families: Enterobacteriaceae, Pseudomonadaceae, Xanthomonadaceae, Rhizobiaceae, Bacillaceae and Alcaligenaceae. Pot experiments showed that 13 strains, capable of producing indole compounds from tryptophan in vitro, could significantly enhance the root and shoot weight of 10-week-old Medicago truncatula seedlings. Compared to non-inoculated seedlings, the root system of inoculated ones was more branched; in addition, the root length, surface area and, especially, the root volume were higher. The 24-h root inoculation with the three selected strains increased the nuclei population in the G1 and S phases, decreased it in the G2 phase and enhanced the WUSCHEL-related Homeobox5 (WOX5) gene expression in root tips and lateral zones. The "arrest" of nuclei in the S phase and the enhancement of the WOX5 gene expression were observed to gradually disappear once the bacterial suspension was rinsed off the seedling roots and the roots were transferred to water for further growth. This study shows that the nodules and rhizosphere of legumes grown on organic farms are a rich source of different PGPB species and provides new data on the ability of these bacteria to interfere with cell cycle and gene expression during the root development.

    更新日期:2019-11-01
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