基于转录组分析外源H_(2)S对拟南芥芥子油苷生物合成的影响

Effect of H_(2)S on glucosinolate biosynthesis in Arabidopsis thaliana based on transcriptomics.

外源硫化氢(H_(2)S)喷施拟南芥幼苗后,利用高通量测序技术对植株地上组织进行转录组测序,分析差异表达基因的生物学功能和代谢通路,探究H_(2)S对芥子油苷生物合成的调控作用.结果表明,100μmol/L H_(2)S处理3d后,拟南芥植株共有3160个基因差异表达,涉及细胞代谢、结合、催化、转录调控、物质转运、信号转导等过程.通过KEGG富集分析发现,差异表达基因在多个初生代谢和次生代谢通路显著富集,其中芥子油苷生物合成途径中9个基因差异表达(8个上调和1个下调),均为参与脂肪族芥子油苷合成的关键酶基因,而吲哚族芥子油苷合成相关基因表达无明显改变.同时,硫代谢、半胱氨酸和甲硫氨酸代谢、谷胱甘肽代谢途径中多个基因上调表达,说明外源H_(2)S可增强体内硫相关代谢活动,进而促进植物体内脂肪族芥子油苷的合成.转录因子差异表达分析显示,正向调控脂肪族芥子油苷合成的MYB29基因表达上调,而抑制其合成的MYB51基因表达水平降低,说明H_(2)S可通过调控MYB转录因子的表达来调节植物体内脂肪族芥子油苷的合成.对芥子油苷生物合成途径中部分关键酶基因及相关MYB转录因子表达模式进行实时荧光定量PCR(qRT-PCR)分析,发现其与测序结果一致,证实了转录组测序结果的可靠性,同时也进一步证明了H_(2)S对植物体内芥子油苷生物合成的调控作用.

Glucosinolates are a group of nitrogen-and sulfur-containing secondary metabolites in cruciferous plants,which are closely related to environmental factors.In this study,transcriptome sequencing of Arabidopsis treated with hydrogen sulfide(H_(2)S)was performed,and the biological functions and metabolic pathways of differentially expressed genes were analyzed to explore the regulatory effect of H_(2)S on glucosinolate biosynthesis in plants.The results showed that a total of 3160 genes were differentially expressed in Arabidopsis seedlings sprayed with 100µmol/L H_(2)S for 3 days,including genes involved in metabolism,binding,catalysis,transcription regulation,transport and signal transduction.KEGG enrichment analysis showed that differentially expressed genes were significantly enriched in multiple primary and secondary metabolism.After exogenous H_(2)S treatment,nine genes(8up-regulated and 1down-regulated)involved in aliphatic glucosinolates biosynthesis were identified to be differentially expressed,but genes associated with indole glucosinolates biosynthesis showed no obvious change.Meantime,several genes that participated in sulfur metabolism,cysteine and methionine metabolism,and glutathione metabolism were up-regulated,suggesting that exogenous H_(2)S can enhance sulfur-related metabolic pathways,which would promote the aliphatic glucosinolates biosynthesis in plants.Transcription factor analysis showed that MYB29 was up-regulated,which could positively regulate the aliphatic glucosinolates biosynthesis.And MYB51,which would inhibit the aliphatic glucosinolates biosynthesis,was down-regulated.These results suggested that H_(2)S could regulate the aliphatic glucosinolates biosynthesis in plants through MYB transcription factors.The qRT-PCR analysis of several genes involved in the glucosinolate biosynthesis verified the accuracy of transcriptomic sequencing,which further proved that H_(2)S participated in the regulation of glucosinolate biosynthesis in plants.