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为探讨小菜蛾Plutella xylostella对病原真菌入侵的免疫防御机制,利用抑制消减杂交技术构建蝉拟青霉Paecilomyces cicadae侵染的小菜蛾幼虫的抑制性差减文库,并对文库进行鉴定。ESTs序列聚类分析共获得412个独立基因。通过同源比对,28.24%ESTs为未知功能基因,71.76%ESTs与已知功能基因序列相似,包括免疫相关、金属离子结合和加工、核酸和蛋白代谢及加工、细胞信号、细胞结构、形状和流动、能量代谢、胁迫和解毒以及其它基因。鉴定出39个可能参与小菜蛾免疫蝉拟青霉侵染的免疫基因,包括:识别分子、蛋白酶及蛋白酶抑制剂、效应因子及其它免疫基因。qRT-PCR结果表明肽聚糖识别蛋白、器官芽生长因子、葛佬素、溶菌酶、酚氧化酶原激活蛋白酶3以及转铁蛋白基因均可诱导表达。免疫相关基因在不同微生物诱导下的表达模式存在不同。结果表明当病原真菌蝉拟青霉侵染寄主小菜蛾后,小菜蛾体内发生了一系列的复杂反应,小菜蛾抵御病原真菌侵染是一个多途径共同作用的复杂过程。该研究为进一步研究小菜蛾抵御病原真菌入侵的分子机制提供基础信息。
In order to investigate the immune defense mechanism of Plutella xylostella against pathogenic fungus invasion, suppression subtractive hybridization was used to construct the subtractive cDNA library of Plutella xylostella infecting Plutella xylostella larvae infected with Paecilomyces cicadae. The library was identified. A total of 412 independent genes were obtained by ESTs sequence clustering analysis. By homology comparison, 28.24% ESTs are unknown functional genes, 71.76% ESTs are similar to known functional gene sequences, including immune related, metal ion binding and processing, nucleic acid and protein metabolism and processing, cell signal, cell structure, shape and Flow, energy metabolism, stress and detoxification and other genes. Thirty-nine immune genes that may be involved in P. cicadae cicadae infection, including recognition molecules, protease and protease inhibitors, effectors and other immune genes, were identified. qRT-PCR results showed that peptidoglycan recognition protein, organ bud growth factor, gelatoin, lysozyme, phenoloxidase-activated proteinase 3, and transferrin gene all induced expression. There are differences in the expression patterns of immune related genes induced by different microorganisms. The results showed that a complex series of reactions occurred in the diamondback moth (Plutella xylostella) after the pathogen fungus Cicada parasitoidum infects the host diamondback moth, and the diamondback moth is a complicated process with multiple pathways to resist the pathogen fungus infection. This study provides the basic information for further studying the molecular mechanism of diamondback moth defense against the invasion of pathogenic fungi.