稻瘟菌WD重复功能域中SSR的变异及其对蛋白结构的影响

SSR Variation in the WD Repeats Domain Genes and It′s Effects on Protein Structure of Rice Blast Fungus, Magnaporthe oryzae

含WD重复功能域的蛋白能够参与信号传导、转录调控、RNA剪切、细胞的凋亡等多种功能,在病原菌与寄主植物蛋白互作的过程中扮演着重要的角色。本研究分析了稻瘟病菌基因组中94个WD功能域基因编码区和调控区中SSR的组成、分布,并检测了7个蛋白编码区中SSR的变异及其对蛋白二级结构的影响。结果表明,WD功能域基因的编码区和调控区中都含有大量的SSR,但是SSR在这些基因的外显子区、内含子区、5'-UTR和3'-UTR区中SSR的组成和分布均不相同;编码区中三碱基和六碱基SSR分布较多,这些SSR基序大都表现为GC含量较高和其所编码的亲水性氨基酸出现的频率远远高于疏水性氨基酸的特点。且检测的7个WD功能域基因的编码区中的SSR位点均具有丰富的多态性,通过Antheprot(DPM)软件预测发现:SSR的变异对蛋白的二级结构有一定影响。这暗示着SSR的变异对致病相关基因的变异起着十分重要的作用。

WD repeats domain containing genes can participate in signal transduction, transcriptional regulation, RNA splicing and apoptosis and so on. WD repeats domain containing genes play important roles in plant-pathogen interactions. SSR component and distribution in coding and regulation region of 94 WD repeats domain containing genes were analyzed in Magnaporthe oryzae, and the SSR variation in 7 coding regions of WD repeats domain contai- ning genes was checked and analyzed its effect on secondary structure of protein. The result showed that abundance of SSRs were in the coding region and regulation region of WD repeats domain containing genes, but both SSR com- ponent and distribution were different among extron, intron, 5＇-UTR and 3＇-UTR ; tri-nucleotide and hexa-nucleotide SSR in coding region were more than other region, and the frequency of hydrophilic amino acids was relatively high- er. In additional, 7 SSR loci of coding region including SSR were polymorphism, and SSR polymorphism of these lo- ci can affect the secondary structure of protein. The data of this study indicated that the mutation of SSR might play an important role for pathogenic gene mutation.