Huanglongbing (HLB) is a severe disease of citrus caused by the bacterium Candidatus Liberibacter. In America, the most common species is Candidatus Liberibacter asiaticus (CLas). In a previous study of the Citrus-HLB pathosystem, our group found differences in CLas multiplication in a population of hybrids obtained by hybridization between Citrus sunki Hort. Ex Tan. and Poncirus trifoliata (L.) Raf

Interactions between insects and plant pathogens have been more enthusiastically studied in the recent decade, especially those relationships which takes the insects as vectors. The spectrum of these interactions ranges from mutualistic to pathogenic. The length of the co-evolutionary process will determine whether a microorganism shares a friend or a foe relationship with its host, and a friendship

Penja pepper (Piper nigrum) produced in Cameroon has long been recognized for its exceptional organoleptic quality. The pepper vine is grown using a support tree (Spondias mombin) in Cameroon. A root disease is associated with plant deaths in both plants. The disease symptoms are characterized by collar cracking and gummosis and the disease was tentatively identified as Armillaria root rot. In this

Citrus mosaic virus (CiMV) and navel orange infectious mottling virus (NIMV) are considered strains of satsuma dwarf virus (SDV). To understand the distribution of different isolates of SDV in China, a field survey was conducted, which allowed for the detection of CiMV and NIMV in citrus plants in Zhejiang and Sichuan provinces, respectively. In the present work, two CiMV isolates, including one named

Root and crown rot (RCR) of dry bean is a disease complex caused by soil-borne pathogens that can limit bean production in Zambia. Identifying the primary pathogen in the complex would facilitate the control as well as breeding for resistance to the disease. Plant tissue samples and DNA embedded FTA® Cards were collected to isolate, detect and molecularly identify RCR pathogens using genus/species

Citrus cultivation is challenging due to the plethora of abiotic and biotic stresses faced by the crop. In recent years, production has been severely affected by diseases such as citrus canker and huanglongbing (HLB). Disease management is hampered as there is no field resistance to these diseases in any of the important commercially planted varieties. Traditionally, conventional breeding approaches

Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae), is the natural vector of the Huanglongbing (HLB) pathogen that presents an unparalleled challenge to citrus production. RNA interference (RNAi) has already shown great potential for insect pest management owing to its high specificity. RNAi technique relies on the delivery of exogenous double-stranded RNAs (dsRNAs) that target essential

In wheat, leaf rust caused by Puccinia triticina Eriks is a major disease that causes major losses in production. In the present study, microsatellite or SSR (simple sequence repeat) markers were developed for P. triticina using the transcriptome data obtained during wheat-P. triticina interactions. A total of 37,268 P. triticina differentially expressed transcripts were obtained in the comparative

Avocado Branch Dieback and Wilting (ABDW) was recently reported on West-Indian avocado (Persea americana var. americana) orchards in the Serrania de Perija, Colombia. This disease is caused by Bionectria pseudochroleuca and transmitted by ambrosia beetles. In this work we estimated the potential distribution of ABDW to map avocado-growing areas at risk of ABDW in Colombia and Venezuela. Disease occurrence

Leaf blight disease in coconut (LBC) caused by Lasiodiplodia theobromae leads to early defoliation and loss of bunches, which negatively impacts coconut fruit yield. The etiology of LBC in Brazil needs to be updated based on modern tools such as DNA sequencing and phylogenetic analysis. A phylogenetic tree using ITS and TEF-1α genes in combination with morphology showed L. theobromae as the most common

Plant pathogenic Xanthomonas species attack a wide range of agriculture crops and is capable of surviving on weeds. In this study, Xanthomonas strains obtained from weeds grown withing vegetable crop fields in the state of Pernambuco, Northeast Brazil, were identified. Bacterial colonies resembling Xanthomonas were obtained from Aeollanthus suaveolens (strain CCRMXe03), Amaranthus lividus (CCRMXe01

This review summarizes the current status of citrus canker in the United States. The disease is present in Florida, Louisiana, and Texas. In Florida, the eradication program ended in 2006 and now citrus canker is endemic to many citrus-growing areas, although it is still possible to find canker-free groves. In endemic areas, the disease is controlled using windbreaks, applying copper-based bactericides

Begomoviruses (family Geminiviridae, genus Begomovirus) are responsible for considerable losses in several tropical crops, more commonly in bean and tomato. Begomoviruses comprise the most numerous and economically destructive group within Geminiviridae. Characteristic symptoms of begomovirus infection in Capsicum chinense (chili pepper, Solanaceae) were observed in smallholder farms in the state of

A putative new virus, physalis rugose mosaic virus (PhyRMV), has been reported more frequently in Physalis peruviana associated with severe symptoms. In this study the damage caused by sap-inoculated PhyRMV in P. peruviana was assessed based on the comparison of host vegetative and reproductive parameters between virus-infected and healthy plants. Infected plants confirmed using molecular assays, showed

Huanglongbing (HLB) caused by ‘Candidatus Liberibacter spp.’ is the most destructive disease for citrus production. These bacteria are disseminated naturally by insect vectors, such as the psyllid Diaphorina citri. However, the transmission of the bacteria vertically from seeds to seedlings has been controversial. Therefore, the objective of this study was to re-investigate the vertical transmission

The emergence of citrus variegated chlorosis (CVC) disease had dramatic consequences to the citrus industry in Brazil. First reported in São Paulo State in 1987, this disease affected approximately 100 million sweet orange trees in the region 20 years later. However, current estimates indicate that the number of diseased trees has been reduced 25-fold since 2009. In this review we summarize research

Fusarium basal rot (FBR) is one of the main onion diseases in Argentina. The Onion Breeding National Program, held at INTA Experimental Station in La Consulta, Argentina, has developed onion breeding lines with increased resistance to FBR through a selection scheme performed under field conditions. The aim of the present work was to evaluate the achieved response to selection in the FBR resistance

Huanglongbing (HLB) has been a serious threat to the citrus industry worldwide. After its first report in São Paulo State, the main citrus production area in Brazil, the disease spread to the States of Minas Gerais, Paraná and Mato Grosso do Sul. Attempts to cure plants or remiss disease symptoms and damages have been evaluated and showed to be inefficient and nonviable. The development of resistant

Phytophthora cinnamomi Rands is a root and collar root pathogen of a great number of wooden plants and crops around the world. The species is heterothallic requiring A1 and A2 mating types for sexual reproduction. In Colombia, P. cinnamomi represents one of the most limiting diseases in avocado (Persea americana Mill). In this work, a total of 207 P. cinnamomi isolates were analyzed from 664 symptomatic

Citrus plants presenting the typical huanglongbing (HLB) symptoms have been associated to 16SrIX phytoplasma in the States of São Paulo (SP), Minas Gerais (MG), Bahia (BA) and, more recently, Distrito Federal (DF), Brazil. Although in SP and MG states ‘Candidatus Liberibacter asiaticus’ is more commonly associated with HLB, single infection by phytoplasmas also occurs. To date, only 16SrIX phytoplasma

Huanglongbing (HLB) is the most damaging disease in citrus. It is caused by the putative bacterium, “Candidatus Liberibacter asiaticus” and is transmitted by the Asian citrus psyllid, Diaphorina citri. Unfortunately, no cure has been found or effective control strategy established for the combat of this disease. Citrus tristeza virus (CTV) was employed successfully for virus induced gene silencing

Tomato leaf curl New Delhi virus (ToLCNDV), a single-stranded (ss)DNA virus(family; Geminiviridae), has become a constraint to the production of crops of the Cucurbitaceae, Solanaceae and Malvaceae across the sub-Continent, south east Asia and, more recently, the western Mediterranean basin. Transgenic Nicotiana benthamiana plants constitutively expressing the phage M13 gene 5 (G5) protein, an ssDNA

Blast, caused by Pyricularia oryzae, is one of the most important diseases affecting rice yield worldwide. This study investigated the potential of silicon (Si) to counteract the effect of picolinic acid (PA), a non-host selective toxin produced by P. oryzae, on the photosynthetic performance, on the activities of defense enzymes, and the antioxidative metabolism of rice plants. Plants were grown in

We report the first full-length genome of a Bougainvillea chlorotic vein banding virus, isolate BCVBV-UNB-01, causing leaf yellowing in a Bougainvillea spectabilis from Brasília, Brazil. The genome, recovered using high throughput sequencing (Illumina HiSeq) and Sanger, consisted of 8665 nucleotides and four typical badnavirus ORFs: ORF I with 456 nt in length, ORF II with 432 nt, ORF III with 6636 nt

This work reports the genome sequence, host responses and transmission assays of two isolates of catharanthus mosaic virus (CatMV) from plants of Mandevilla sp. in the state of São Paulo, Brazil. The complete genome sequences of CatMV isolates, M1 and M2, comprised 9593 and 9711 nucleotides, respectively. The deduced polyprotein showed 99% (M1) and 84% (M2) identities with the corresponding amino acid

Since citrus canker was first described in the early 1900’s, four major types and three species of pathogenic xanthomonads associated to citrus were identified based on the characteristic symptoms and host range. Type A, caused by X. citri subsp. citri, develops typical raised cankered lesions and is pathogenic on most commercial citrus species and cultivars. Types B and C are caused by X. citri pv

According to the most recent regulation, published in 2018, areas or states of Brazil where citrus canker is endemic are no longer obliged to eradicate citrus trees affected by the disease as in the past 60 years. Instead, growers have to adopt a set of control measures, such as copper sprays, windbreaks, and control of the citrus leaf miner to minimize the impact of the disease on fruit quality and

Xanthomonas citri subsp. citri (Xcc) causes citrus bacterial canker (CBC) on several Citrus species. Xcc requires bacterial aggregation and biofilm formation to colonize the host plant. Those biofilms are dependent on the environmental condition and their structures differ according to the host range of the Xcc strain. Herein, we have visualized and evaluated the extracellular structures produced by

Nowhere in the U.S. is Huanglongbing (HLB) under adequate control due to the lack of effective tools to reduce spread of the vector, Diaphorina citri (Asian citrus psyllid), and transmission of the associated pathogen, Candidatus Liberibacter asiaticus, in the absence of disease resistance in commercial citrus varieties. In Florida, Asian citrus psyllid was well established by the time of HLB discovery

Root-knot nematodes are pathogenic to a wide range of plants worldwide and can reduce the yield potential of important crops. The objective of this study was to investigate the potential effects of yeast fermentation broths (YFBs) on the hatching of Meloidogyne incognita second-stage juveniles (J2s) in vitro. In addition, application methods of the yeasts for the control of the nematode in soybean

The apple stem grooving virus (ASGV) and apple stem pitting virus (ASPV) are among the major viral species that infect apple trees and are responsible for substantial damage and loss. The aim of this study was to assess the effectiveness of droplet-vitrification cryotherapy technique in eradication of ASGV and ASPV in Malus prunifolia “Marubakaido” apple rootstock plants. The axillary shoot tips were

Decline and death of young vines is a worldwide problem for viticulture that may lead to economic loss. Fungal pathogens have been associated with trunk and root diseases, including the black foot disease that affects the performance of the vineyards. Fungicides have not worked efficiently to control the disease and alternative methods should be investigated. We evaluated the potential of Bacillus

Symptoms of general wilting and yellowing were found affecting Beta vulgaris L. (sugar beet, fodder beet and chard) in the Argentinean region of Bahía Blanca (Buenos Aires province), Valle Medio, and Valle Inferior de Rio Negro (Patagonia region). PCR amplification of the 16S rRNA region showed presence of phytoplasma in approximately 80% of the samples from symptomatic plants. Phylogenetic analyses

For the first time, the near-complete genome sequence of the betacarmovirus, hibiscus chlorotic ringspot virus (HCRSV) isolated from the Americas is disclosed. High throughput sequencing of the total RNA extract from a Hibiscus-rosa sinensis (L.) plant collected in São Paulo state, Brazil, revealed the genome sequence of HCRSV isolate SBO1, which is 3945 nucleotides long and shows 93.1% nucleotide

Between 2002 and 2017, asexual morphs of powdery mildews (Erysiphales) were collected in Thailand from the following hosts: Cassia fistula, Castanopsis argyrophylla, Durio zibethinus, Jatropha curcas, Kydia calycina, Hevea brasiliensis, Hodgsonia macrocarpa, Mallotus philippinensis, Mimosa pudica, Nephelium lappaceum, Tamarindus indica and Ziziphus jujuba. Combined molecular and morphological analyses

Leaf blast, caused by the hemibiotrophic fungus Pyricularia oryzae, is the most important disease affecting rice production worldwide. The present study investigated the potential of using glutamate (Glu) to increase rice resistance to leaf blast. Rice plants (cultivar Metica-1) were non-supplied (−Glu) or supplied (10 mM) (+Glu) with Glu and non-inoculated or inoculated with P. oryzae. Leaf blast

This paper should have published with open access. It has been corrected online.

Vascular wilt caused by Fusarium oxysporum is the most damaging disease in cape gooseberry (Physalis peruviana L.) production. In this study, we isolated and biochemically characterized endophytes and rhizospheric bacterial isolates with antagonistic activity against F. oxysporum from cape gooseberry plants. Bacterial isolates were evaluated under in vitro conditions for their antagonistic capacity

The association between reactive oxygen species (ROS) production and potato resistance to the hemibiotrophic pathogen Phytophthora infestans is poorly understood. In this study, the concentrations of hydrogen peroxide (H2O2), malondialdehyde (MDA), and soluble phenolics, as well as the activities of superoxide dismutase, catalase, and ascorbate peroxidase were measured during the early biotrophic and

Identifying resistance to plant-parasitic nematodes in yams is a major challenge in yam breeding programmes due partly to insufficient planting material (tubers) for evaluation. Susceptible yam cultivar, TDr 93-31 was inoculated with 0 (control), 200, 500, 1000 and 2000 eggs/individuals each of Meloidogyne incognita, Scutellonema bradys and Pratylenchus brachyurus. Vine cuttings of two cultivars each

Potato yellow mosaic virus (PYMV) is one of the most important begomoviruses infecting tomatoes in the Caribbean basin. Viruses of this group are transmitted by whiteflies of the Bemisia tabaci cryptic species complex. Within this complex, the whitefly referred to as Middle East-Asia Minor 1 (MEAM1) is globally spread and recognised as a highly efficient begomovirus vector. This study reports the whole

Tomato chlorosis virus (ToCV), transmitted by whiteflies, is an important virus that infect tomato plants worldwide. The incidence of ToCV in tomato crops in Brazil is usually high, especially in the Distrito Federal and the state of Goiás, in the central part of the country. We conducted a survey in central Brazil to detect natural infections of ToCV in weeds near tomato plants with typical criniviral

Common bean is an economically important crop grown in several areas in the world. Among the constraints for this crop development, bean rugose mosaic virus (BRMV) infections can potentially lead to serious yield reduction. Genetic resistance is the most effective control method, and the search for sources of resistance is an essential step. The objective of this study was to biologically characterize