稻瘟病菌MoSSPs生物信息学分析与MoSSP7定位研究

Bioinfomatics Analysis of Mo SSPs and Subcellular Localization of MoSSP7 in Magnaporthe oryzae

真核生物中,SET蛋白在基因转录的表观遗传调控方面是必需的,基因转录通过催化组蛋白赖氨酸甲基化而受调控。某些病原性细菌和病毒可以分泌SET蛋白去修饰宿主基因组,进而抑制宿主细胞免疫反应。真菌中SET蛋白已有较为深入的研究。但是,分泌型SET蛋白的功能,很大程度上仍然未知。为了研究稻瘟病菌分泌型SET蛋白的功能,我们从稻瘟病菌数据库中搜索获得8个预测的分泌型SET蛋白,分别命名为MoSSP1-8。通过在线的生物信息学工具分析了Mo SSP蛋白功能结构域和理化特性。RNA-Seq数据揭示其中6个基因在侵染时期表达量上调。序列比对和进化分析结果表明,Mo SSP7及其真菌同源蛋白在SET结构域都具有保守的基序,并且在进化上关系较近。共聚焦显微观察结果表明,在侵染菌丝中MoSSP7蛋白主要集中在BIC上,这说明它是一个胞质效应因子。

SET proteins are required for the epigenetic regulation of gene transcription by catalyzing the histone lysine methylation in the eukaryotic organisms. Some of the pathogenic bacteria and viruses can secrete the SET proteins to modify the host genome and consequently attenuate the host immunity. In fungi, the SET proteins have been well-studied. However, the function of secreted SET proteins(SSPs) remained largely unknown. To explore the function of SSP proteins in Magnaporthe oryzae, we searched in the Magnaporthe grisea database and identified 8putative SSP proteins, termed MoSSP1-8 respectively. The functional domains and the physical/chemical properties were analyzed by using online bioinformatic tools. The RNA-Seq data revealed that six Mo SSP genes were upregulated during the infection. Sequence alignment and phylogenic results indicated that the Mo SSP7 protein and its homologs protein in fungi shared the conserved motifs in SET domain, and had close phylogenetic relationship. The observation by confocal fluorescence microscopy showed the Mo SSP7 protein was mostly accumulated on BIC in the invasive hyphae, which suggested that MoSSP7 protein was a cytoplasmic effector.