稻瘟病菌效应蛋白MoIEEP1功能初探

Functional analysis of MoIEEP1 effector in Magnaporthe oryzae

由稻瘟病菌引起的稻瘟病是全球最严重的植物真菌病害之一,严重威胁水稻生产安全。效应蛋白是病原菌与植物对抗过程中分泌产生的一种蛋白质,可作为毒力因子促进侵染或作为无毒因子触发防御反应。本研究对实验室前期筛选到的在稻瘟病菌侵染早期诱导表达的效应蛋白(infection-induced expression effector protein 1,MoIEEP1)进行了功能验证与分析。结果表明:MoIeep1在稻瘟病菌侵染初期8 h表达量最高;信号肽和亚细胞定位分析验证该蛋白N端含有17个氨基酸的信号肽且在水稻原生质体中呈明亮点状的定位信号,初步推测该定位信号为过氧化物酶体或线粒体等细胞器;与野生型菌株Guy11相比,MoIeep1基因敲除突变体菌丝生长无明显差异,但其致病性受到影响。以上研究结果为进一步探究该蛋白质的作用机理打下良好基础,也为揭示其他效应蛋白在稻瘟病菌侵染水稻过程中的功能提供新的理论依据。

Rice blast disease caused by Magnaporthe oryzae is one of the most severe plant fungal diseases in the world and seriously threatens the safety of rice production.The effectorsis a type of protein secreted by the pathogen in the process of fighting against plants.It can be used as a virulence factor to promote infection or a non-toxic factor to trigger defense response.In this study,we performed a functional screening and analysis of an effector(infection-induced expression effector protein 1,MoIEEP1)that is specifically expressed during the early infection stage of M.oryzae.The results showed that MoIeep1 had the highest expression at 8 h in the early infection stage of M.oryzae;signal peptide and subcellular localization analysis verified that MoIEEP1 contained a 17-amino acid signal peptide at the N-terminus and showed a bright spot-like localization signal in rice protoplasts.It was presumed that the localization was in peroxisome or mitochondria.Compared with the wild-type strain Guy11,MoIeep1 knockout mutants showed no significant difference in mycelium growth,but affected its pathogenicity.These results established the foundation for further exploring the functional mechanism of this protein,and also provide a new theoretical basis for revealing the function of other effectors during the process of rice blast infection by M.oryzae.