木薯MeSAP13基因的克隆及其抗细菌性枯萎病功能鉴定

胁迫相关蛋白（stress-associated proteins, SAPs）在植物对胁迫应答和胁迫调控中起重要作用。木薯是我国重要的粮食作物和经济作物,细菌性枯萎病（cassava bacterial blight, CBB）已严重危害我国木薯产业的健康发展。为了探讨木薯MeSAP基因在抗细菌性枯萎病中的作用,本研究克隆了我国主栽木薯品种‘华南8号’（SC8）的MeSAP13基因,分析该基因在细菌性枯萎病病原菌侵染时的表达模式及其编码蛋白的基本特性。利用基于木薯花叶病毒介导的基因沉默（virus induced gene silencing, VIGS）技术抑制了MeSAP13基因在木薯SC8叶片中的表达,通过接种细菌性枯萎病病原菌XpmHN11对MeSAP13的抗病功能进行抗性鉴定。结果发现：在病原菌XpmHN11侵染叶片3 d后MeSAP13基因表达量显著上调,说明木薯MeSAP13基因能够响应病原菌的侵染;在VIGS载体转化木薯叶片40 d后发现,与转化pCsCMV-A载体的对照叶片相比,MeSAP13在转化pCsCMV-MeSAP13叶片中的表达量显著下调了40%~60%,表明通过VIGS技术成功抑制了MeSAP13在木薯叶片中的表达。将病原菌XpmHN11接种至MeSAP13基因沉默叶片和对照植株叶片,发现MeSAP13基因沉默植株接种叶片的水渍状病斑面积显著大于对照植株接种叶片。分析侵染后0、3、6 d病原菌XpmHN11的繁殖情况发现,在侵染后3 d和6 d的MeSAP13基因沉默植株接种叶片中,其病原菌数量显著高于对照植株接种叶片。以上研究结果表明,抑制MeSAP13基因的表达,降低了木薯对细菌性枯萎病的抗性。

Cloning of Cassava MeSAP13 Gene and Identification of Its Function Against Cassava Bacterial Blight

Stress-associated proteins (SAPs) play an important role in plant response to stress and stress regulation. Cassava is an important food crop and economic crop in China, however, cassava bacterial blight (CBB) has seriously harmed the healthy development of cassava industry in China. In order to explore the role of cassava MeSAP gene in cassava resistance to CBB, this study cloned the MeSAP13 gene of cassava cultivar SC8, and analyzed the expression pattern of this gene in the infestation of bacterial blight pathogens and the basic characteristics of the coding protein. The expression of MeSAP13 in cassava SC8 leaves was inhibited by cassava mosaic virus-mediated gene silencing (VIGS) technology, and the resistance function of MeSAP13 was identified by inoculating the bacterial blight pathogen XpmHN11. The results showed that the expression of MeSAP13 was significantly upregulated 3 d after the pathogen XpmHN11 infected the leaves, indicating that MeSAP13 could respond to the infection of pathogenic bacteria; after 40 days of transformation of cassava leaves with VIGS vector, it was found that the expression of MeSAP13 in the transformed pCsCMV-MeSAP13 leaves was significantly reduced by 40%-60% compared with the control leaves of the transformed pCsCMV-A vector, showing that the expression of MeSAP13 in cassava leaves was successfully inhibited by VIGS technology. The pathogen XpmHN11 was inoculated into the leaves of the MeSAP13 silencing and control plants, and the water-stained lesion area on the inoculation leaves of the MeSAP13 gene-silencing plants was found to be significantly larger than that of the control plants. We analyzed the reproduction of the pathogen XpmHN11 at 0 d, 3 d and 6 d after infection, the number of pathogens in the inoculated leaves of MeSAP13 silencing plants 3 d and 6 d after infection was significantly higher than that of the control plants. The above results show that inhibiting the expression of MeSAP13 reduces the resistance of cassava bacterial blight.