基于RNA-Seq的甘蔗响应鞭黑粉菌侵染的早花相关基因挖掘

Identification of Early Flowering Related Genes of Sugarcane in Response to Sporisorium scitamineum Infection Based on RNA-Seq

甘蔗鞭黑粉菌(Sporisorium scitamineum)是引起甘蔗鞭黑穗病(sugarcane smut)的重要病原菌,侵染甘蔗后通常诱导顶端分生组织产生灰黑色“黑鞭”,在部分甘蔗品种(系)中能诱导植株提前开花,但其作用机制仍不明确。为了探究甘蔗响应鞭黑粉菌侵染的开花相关基因及其表达模式,本研究以同期健康和感染鞭黑粉菌的桂糖42甘蔗品种为实验材料进行转录组测序分析,共筛选出了3276个显著差异表达基因,其中1677个基因上调表达(P<0.05),1599个基因下调表达(P<0.05)。GO富集分析发现差异表达基因主要集中在生物合成过程、核糖体、核糖核蛋白复合体、核糖体结构成分等小类中。KEGG富集结果显示差异表达基因主要集中在氨基酸的生物合成、嘌呤代谢、碳代谢、吞噬作用等代谢通路。筛选到30个与开花途径相关的差异表达基因,并对其中的FT1、PIE1、GID1、GA20ox-1、GA20ox-2等基因进行了qRT-PCR验证,qRT-PCR结果与转录组测序结果基本一致,验证了转录组测序结果的可靠性。本研究结果为解析甘蔗鞭黑粉菌诱导甘蔗提前开花表型的分子机理提供了重要的候选基因,对甘蔗的育种也有重要的参考价值。

Sporisorium scitamineum,the pathogen of destructive disease smut,usually causes abnormal growth of meristematic tissue and forms a“black whip”in meristem tissues.In some cases,it induces formation of flowering structures in some sugarcane cultivars(genotypes),but the exact mechanism remains unclear.In order to explore flowering related genes and the expression patterns in sugarcane in response to infection by S.scitamineum,the healthy and S.scitamineum infected‘guitang42’sugarcane cultivar samples were analyzed by transcriptome sequencing.A total of 3276 differentially expressed genes(DEGs)were identified,of which 1677 genes were up-regulated(P<0.05)and 1599 genes down-regulated(P<0.05).The DEGs were mostly enriched in the biosynthesis process,ribosome,ribonucleoprotein complex,ribosome structural components,etc.according to GO enrichment analysis.The KEGG analysis showed that the DEGs were mostly enriched in amino acid biosynthesis,purine metabolism,carbon metabolism,phagocytosis,and other metabolic pathways.Also,out of 30 DEGs were identified to be associated with flowering,and the representative genes such as FT1,PIE1,GID1,GA20ox-1,GA20ox-2 were validated by qRT-PCR.The qRT-PCR results were consistent with the transcriptomic data,confirming the dependability of the transcriptome sequencing results.The findings would present essential candidate genes for revealing the mechanism of early flowering of sugarcane plants caused by S.scitamineum,and lay the foundation for disease resistance breeding.