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PevD1是一种大丽轮枝菌(Verticillium dahliae)分泌蛋白,具有激发烟草过敏反应(HR)和系统获得性抗病(SAR)的功能。为明确蛋白PevD1诱导棉花抗病性及其作用机制,本文利用大肠杆菌表达、纯化的PevD1诱导棉苗植株,检测棉苗对大丽轮枝菌的抗性及免疫应答反应。结果表明,大肠杆菌表达的PevD1重组蛋白不是棉花品种“新陆早42号”的致萎因子,叶片注射8μg/mL PevD1蛋白诱导3 d后根部接种大丽轮枝菌,15 d后PevD1处理组病害减轻率达35.04%。PevD1能诱导棉花叶片抗性早期信号分子H_2O_2产生和NO积累,维管束细胞壁加厚、木质素和酚类物质的积累。另外,PevD1处理能提高防御酶PAL、POD和PPO活性,提高棉花抗性基因和木质素合成相关基因PAL、C4H1、4CL的转录水平。说明PevD1通过激发棉花免疫系统而提高抗病性,该研究不仅为利用PevD1蛋白激发子控制棉花黄萎病提供了科学依据,同时也为阐明棉花与大丽轮枝菌互作机理提供了理论基础。
PevD1 is a secreted protein of Verticillium dahliae that functions to stimulate tobacco allergy (HR) and system-acquired disease resistance (SAR). In order to clarify the mechanism of disease resistance induced by PevD1 and its mechanism of action, this paper used the E. coli expression and purification of cotton seedlings induced by PevD1 to test the resistance of cotton seedlings to Verticillium dahliae and the immune response. The results showed that PevD1 recombinant protein expressed in Escherichia coli was not the virulence factor of cotton cultivar “Xinluzao 42”, and the roots were infected with PevD1 after 3 days of inoculation with 8μg / mL PevD1 protein. After 15 days PevD1 Treatment group disease reduction rate of 35.04%. PevD1 could induce early signal molecule H 2 O 2 generation and NO accumulation in cotton leaves, thickened vascular wall, accumulation of lignin and phenols. In addition, PevD1 treatment increased the activities of defense enzymes PAL, POD and PPO, and increased the transcriptional levels of cotton resistance genes and lignin synthesis related genes PAL, C4H1 and 4CL. These results indicate that PevD1 can enhance the disease resistance by stimulating the cotton immune system. This study not only provides a scientific basis for the control of Verticillium dahliae with PevD1 protein exciton, but also provides a theoretical basis for elucidating the interaction mechanism between cotton and Verticillium dahliae .