转录组分析揭示光诱导转录因子StMYB113调控马铃薯块茎表皮叶绿素合成

Transcriptome analysis reveals the regulatory role of the transcription factor StMYB113 in light-induced chlorophyll synthesis of potato tuber epidermis

马铃薯块茎见光变绿严重影响了其食用安全性和经济效益,但光诱导马铃薯块茎合成叶绿素的机制尚不清楚。本研究对不同光照时间处理的马铃薯块茎进行了相关代谢产物分析,结果表明随着光照时间的延长块茎叶绿素含量逐渐上升,且在36 h时叶绿素含量上升显著,块茎表皮也随之出现明显的绿色;对光诱导0、6、36 h的样品的转录组测序和生物信息学分析共鉴定到5646个差异表达基因(DEGs),进一步通过共表达聚类分析和qRT-PCR定量验证, 9个主要的叶绿素生物合成结构基因StGAS1、StCHLD、StCrd1、StHEMA、StGUN4、StPORA、StUROD、StCHLM、StCHLG以及6个转录因子StSBP、StLSD、StGATA、StWRKY、StMYB-like、StMYB113显著上调。对这9个结构基因的启动子序列的顺式作用元件的预测结果显示它们都含有多个MYB结合位点,启动子元件分析和转录激活验证试验结果表明StMYB113具有光响应元件,并能在烟草激活StUROD的表达,由此说明StMYB113可能受光响应且调控马铃薯块茎的见光变绿。本研究结果为光诱导马铃薯块茎叶绿素合成调控机制研究提供参考,对减少马铃薯块茎绿化造成的损失具有重要意义。

Light-induced greening of tubers seriously affects its safety and economic benefits,but the mechanism of light-induced chlorophyll synthesis in potato tubers remains unclear.In this study,the related metabolites of potato tubers with different light durations were analyzed.The results were as follows:When the light duration prolonged,the chlorophyll content of the tubers gradually increased.Moreover,the chlorophyll content increased significantly at 36 hours,with which the tuber skin turned green obviously.Transcriptome sequencing and bioinformatics analysis were carried out on the samples taken at 0 hour,6 hours,and 36 hours,and 5646 differentially expressed genes(DEGs)were identified.According to the co-expression cluster analysis and quantitative RT-PCR verification results,9 major structure genes of chlorophyll biosynthesis pathway(StGAS1,StCHLD,StCrd1,StHEMA,StGUN4,StPORA,StUROD,StCHLM,and StCHLG)and 6 transcription factors(StSBP,StLSD,StGATA,StWRKY,StMYB-like,and StMYB113)were significant induced.Predictions of the cis-acting elements of the promoter sequences of these 9 structural genes indicated that they all contained multiple MYB binding sites.Promoter element analysis and transcriptional activation validation further revealed that StMYB113 had a light-responsive element and could activate the expression of StUROD in tobacco.Therefore,StMYB113 may be light-responsive and be able to regulate potato tuber greening in the light.This study provides a reference for the research on the regulatory mechanism of light-induced chlorophyll synthesis in potato tubers,which is important for reducing the loss caused by greening of potato tubers.