木薯乙烯信号途径重要基因的生物信息学及表达分析

Differential Expression and Bioinformatics Analysis of Related Genes of Ethylene Signaling Pathway in Cassava

木薯是全球三大薯类作物之一,具有抗逆、耐瘠的特性。气态植物激素乙烯在植物生长发育和应对生物及非生物胁迫过程中起着重要作用。本研究收集了木薯乙烯信号途径中的受体基因家族(MeERS1,MeERS2,MeERS3,MeERS4,MeERS5,MeETR2和MeEIN4)和部分转录因子基因家族(MeEIL1,MeEIL2),通过生物信息学方法对这些基因进行了多重比对、保守结构域预测和聚类分析,并采用实时荧光定量PCR的方法测定它们在木薯华南五号不同组织器官中的转录表达水平。生物信息学分析结果表明,受体蛋白都含有高度保守的GAF和HisKA结构域,而转录因子则含有EIN3结构域。另外,受体蛋白都具有跨膜结构域,有的还具有信号肽,而转录因子不具有这些结构域。转录表达分析结果表明,MeERS1、MeERS3、MeEIN4和MeEIL2成组成型表达,在茎、根、块根和叶中没有明显的表达差异;而另一部分基因则成组织器官差异型表达,其中MeERS2和MeETR2主要在茎和叶中高表达,MaERS4、MaERS5和MaEIL1主要在根、茎和叶中表达,在块根中表达量较低。这些结果将为进一步研究乙烯信号途径在木薯抗胁迫过程中的功能奠定基础。

Cassava is one of the three top potato crops in the world, with many characters such as drought- and leanness-tolerance. The gaseous ethylene, as a plant hormone, regulates a variety of developmental process and response to biotic and abiotic stress in plant. In this study, we cloned members of ethylene receptor gene family （MeERS1, MeERS2, MeERS3, MeERS4, MeERSS, MeETR2, MeEIN4） and partial ethylene insensitive 3-like gene family （MeEIL1, MeEIL2） in cassava. The multiple alignment, phylogenetic tree, and conserved domains of those genes were performed by the bioinformatic methods. The differential expression of those genes in cassava SC5 was performed by real-time fluorescence quantitative polymerase chain reaction. The results showed that ethylenereceptors contained the conserved domains GAF and HisKA, and EILs containing EIN3 domain. There were existing transmembrane structures in ethylene receptors, even some of them having signal peptide while EILs didn＇t. MeERS1, MeERS3, MeEIN4, and MeEIL2 were constitutive expression genes, and those expression had no differences in different tissues of cassava, while the others showed differences in expression level. The expression level of MeERS2 and MeETR2 in stem and leaf were higher than root and root tuber, and expression of MaERS4, MaERS5, MaEIL1 mainly in root, stem and leaf, less in root tuber. It will provide a theoretical basis for further research on the functions of ethylene signal transduction resistance to environment stress in cassava.