水杨酸和霜霉病诱导黄瓜PCD过程中线粒体相关基因的表达分析

Expression Analysis of Mitochondria-related Genes During PCD Induced by Salicylic Acid and Downy Mildew in Cucumber

为研究水杨酸(SA)和霜霉病两种处理诱导黄瓜PCD过程中线粒体相关基因的表达差异及其引发的黄瓜叶片PCD发生方式。选择长出4片真叶的黄瓜植株为试材,用10 mmol/L SA处理叶片,用5×105-10×105个孢子囊/m L的霜霉菌菌液接种叶片,分别取SA处理0、3、12和24 h及接种菌液0、36、72和96 h的叶片提取RNA,用q RT-PCR技术分析16个线粒体相关基因的表达动态。实验结果表明:16个基因在SA处理和霜霉病接种后都表达,呈现相似或相悖的表达趋势,说明SA诱导的PCD相关基因与霜霉病诱导的PCD信号通路有明显的相互联系,其中11个基因在霜霉病处理中结果与SA处理相似皆为上调,5个基因在SA处理中为上调表达,在霜霉病处理过程中却是下调表达,这也表明SA和霜霉病引发抗病信号途径存在差异,从而使黄瓜叶片PCD发生方式不同。通过查找文献分析16个基因的功能及研究现状,这些基因属于4个功能类群,主要包括参与线粒体膜转运、细胞呼吸作用、蛋白质合成、折叠和转运、线粒体信号转导以及其他或未知功能。

In order to study the differences in the expression of mitochondria-related genes during the process of cucumber PCD inducedby salicylic acid（SA）and downy mildew as well as the way of PCD occurred in cucumber leaves,the leaves were treated with 10 mmol/L SAand inoculated with the spore suspensions（5×10^5-10×10^5 Spores/ml）of Pseudoperonospora cubensis at the four-leaf period of cucumber.Total RNAs were extracted from the leaves treated with SA after 0,3,12,and 24 h and the leaves treated with P. cubensis after 0,36,72,and 96 h. The expressions of the 16 mitochondria-related genes were analyzed using q RT-PCR techniques. The results showed that the 16 genes expressed after SA-treatment and P. cubensis infection with a similar or contrary expression trend,indicating that the genes with PCDinduced by SA were significantly related to the signaling pathway of PCD induced by downy mildew. Eleven genes of them were up-regulatedboth in downy mildew treatment and in SA treatment,5 genes were up-regulated in SA treatment,but were down-regulated in downy mildewtreatment,showing that there were differences in disease resistance signaling pathways induced between by SA and downy mildew,whichthen resulted in the different occurrence patterns of PCD in cucumber leaves. These 16 genes belonged to 4 functional groups,includingmitochondrial membrane transport,cell respiration,protein synthesis,folding and transport,mitochondrial signal transduction and otherunknown functions.