油菜素内酯对水稻矮化突变体幼苗生长影响转录组学分析

Transcriptomic Analysis for the Effect of Brassinolide on Seedling Growth in Rice Dwarf Mutant

油菜素内酯(brassinosteroid,BR)是在植物发育和防御中起关键作用的一种类固醇激素。本研究以一个水稻BR不敏感型矮化突变体D26、外源BR激素处理突变体与野生型进行了转录组学分析。结果表明,在D26突变体中,共筛选到692个差异显著表达基因,其中477个基因在突变体中上调表达,221个下调表达;外源BR处理D26突变体中,共筛选到1526个差异表达基因,其中936个上调表达,560个下调表达。突变体与野生型相比,GO(Gene ontology)功能富集分析发现,差异基因主要富集在裂解酶活性、作用于磷酸盐的碳氧裂解酶活性、萜烯合酶活性、铁离子结合、双加氧酶活性、氧化还原酶活性、四吡咯结合和血红素结合等条目;外源BR处理突变体后,GO富集主要集中于双加氧酶活性、氧化还原酶活性、四吡咯结合和血红素结合等条目上。KEGG富集分析表明,二萜生物合成途径是BR应答的一个重要代谢通路。利用荧光定量PCR检测了参与二萜生物合成富集的主要基因的表达,结果与转录组结果是一致的。研究通过转录组学揭示了D26突变体与BR应答上、下游基因,提升了对BR反馈应答机制的认识。

Brassinosteroid(BR)plays a key role in plant development and defense as a steroid hormone.In this study,a rice BR insensitive dwarf mutant D26,the mutant treated with exogenous BR and the wild type were used for transcriptome analysis.The results showed that 692 differential expressed genes were screened in D26 mutant,including 477 up-regulated genes and 221 down-regulated genes.After treated with exogenous BR,1526 differential expressed genes were screened,including 936 up-regulated genes and 560 down-regulated genes.Compared with wild-type and mutants,gene functional enrichment analysis showed that the differential genes were mainly enriched in lysase activity,carbon oxygen lyase activity acting on phosphate,terpene synthase activity,iron ion binding,dioxygenase activity,oxidoreductase activity,tetrapyrrole binding and heme binding.After exogenous BR treatments,GO enrichment was mainly concentrated in dioxygenase activity,oxidoreductase activity,tetrapyrrole binding and heme binding.KEGG enrichment analysis showed that diterpenoid biosynthesis pathway was an important metabolic pathway in BR response.The expression of major genes involved in diterpenoid biosynthesis was validated by fluorescence quantitative PCR.The results showed that real expression levels were consistent with the transcriptome analysis.The study revealed the upstream and downstream genes of D26 mutant on BR response through transcriptome,and improved the understanding of BR feedback response mechanism.