Key message

The present study provides comparative transcriptome analysis, besides identifying functional secondary metabolite genes of Plumbago zeylanica with pharmacological potential for future functional genomics, and metabolomic engineering of secondary metabolites from this plant towards diversified biomedical applications.

Abstract

Plumbago zeylanica is a widely used medicinal plant of the traditional Indian system of medicine with wide pharmacological potential to treat several disorders. The present study aimed to carry out comparative transcriptome analysis in leaf and root tissue of P. zeylanica using Illumina paired end sequencing to identify tissue-specific functional genes involved in the biosynthesis of secondary metabolites, contributing to its therapeutic efficacy. De novo sequencing assembly resulted in the identification of 62,321 “Unigenes” transcripts with an average size of 1325 bp. Functional annotation using BLAST2GO resulted in the identification of 50,301 annotated transcripts (80.71%) and GO assigned to 18,814 transcripts. KEGG pathway annotation of the “Unigenes” revealed that 2465 transcripts could be assigned to 242 KEGG pathway maps wherein the number of transcripts involved in secondary metabolism was distinct in root and leaf transcriptome. Among the secondary metabolite biosynthesis pathways, the cluster of “Unigenes” encoding enzymes of ‘Phenylpropanoid biosynthesis pathway’ represents the largest group (84 transcripts) followed by ‘Terpenoid Backbone biosynthesis’ (48 transcripts). The transcript levels of the candidate unigenes encoding key enzymes of phenylpropanoid (PAL, TAL) and flavanoid biosynthesis (CHS, ANS, FLS) pathways were up-regulated in root, while the expression levels of candidate “Unigenes” transcript for monoterpenoid (DXS, ISPF), diterpenoid biosynthesis (SPS, SDS) and indole alkaloid pathways (STR) were significantly higher in leaf of P. zeylanica. Interestingly, validation of differential gene expression profile by qRT-PCR also confirmed that candidate “Unigenes” enzymes of phenylpropanoid and flavonoid biosynthesis were highly expressed in the root, while the key regulatory enzymes of terpenoid and indole alkaloid compounds were up-regulated in the leaf, suggesting that (differences in) the levels of these functional genes could be attributed to the (differential) pharmacological activity (between root and leaf) in tissues of P. zeylanica.

中文翻译：

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从头转录组分析揭示了参与白花丹主要次生代谢物生物合成途径的候选基因的组织特异性表达：对药理学潜力的影响。

 关键信息

本研究提供了比较转录组分析，此外还鉴定了白花丹 ( Plumbago zeylanica)的功能性次生代谢基因，该基因具有未来功能基因组学的药理学潜力，以及该植物次生代谢物的代谢组学工程，以实现多样化的生物医学应用。

 抽象的

白花白花丹 (Plumbago zeylanica)是印度传统医学体系中广泛使用的药用植物，具有治疗多种疾病的广泛药理潜力。本研究旨在利用 Illumina 配对末端测序技术对P. zeylanica的叶和根组织进行比较转录组分析，以鉴定参与次生代谢物生物合成的组织特异性功能基因，从而有助于其治疗功效。从头测序组装鉴定出 62,321 个“Unigenes”转录本，平均大小为 1325 bp。使用 BLAST2GO 进行功能注释，识别出 50,301 个带注释的转录本（80.71%），并将 GO 分配给 18,814 个转录本。 “Unigenes”的KEGG通路注释显示，2465个转录本可以分配到242个KEGG通路图谱中，其中参与次生代谢的转录本数量在根和叶转录组中是不同的。在次级代谢物生物合成途径中，编码“苯丙素生物合成途径”酶的“Unigenes”簇代表最大的组（84 个转录本），其次是“萜类骨架生物合成”（48 个转录本）。编码苯丙素（ PAL，TAL ）和黄酮生物合成（ CHS，ANS，FLS ）途径关键酶的候选unigenes的转录水平在根中上调，而单萜候选“Unigenes”转录本的表达水平（ DXS， P. zeylanica叶中ISPF ）、二萜生物合成（ SPS、SDS ）和吲哚生物碱途径（ STR ）显着较高。有趣的是，通过qRT-PCR对差异基因表达谱的验证也证实了苯丙素和类黄酮生物合成的候选“Unigenes”酶在根中高表达，而萜类化合物和吲哚生物碱化合物的关键调节酶在叶中上调，表明这些功能基因的水平（差异）可归因于P. zeylanica组织中的（差异）药理活性（根和叶之间）。