水稻纹枯病菌谷胱甘肽S-转移酶基因的生物信息学及表达分析

摘要

通过生物信息学方法及表达分析对水稻纹枯病菌谷胱甘肽S转移酶基因(Rsgst)的功能进行探索.通过水稻纹枯病菌RSIADB基因组数据库查找Rsgst序列,确定该基因在水稻纹枯病菌基因组中的精确位置.利用生物信息学软件预测Rsgst编码蛋白氨基酸序列的基本信息,并使用 MEGA 5.0软件构建同源蛋白的系统发育树,最后用qRT-PCR检测Rsgst在菌核发育过程中的基因表达量,同时测定GST的酶活性.结果表明,Rsgst全长1207 bp,该基因共编码277个氨基酸残基,其编码蛋白分子量为30.90 ku,理论等电点为9.42.该蛋白二级结构中以α-螺旋为主,占41.52%.系统发育树表明,水稻纹枯病菌GST蛋白与担子菌类玉米丝黑穗病菌GST蛋白亲缘关系最近.qRT-PCR结果表明,Rsgst在水稻纹枯病菌菌核发育过程中表达量不断上调,基因最高表达量是在第60小时,为7.64,而Rsgst的最高酶活性是在第5天,其酶活为0.375 U/μg.结果可为预测水稻纹枯病菌中Rsgst基因的功能奠定基础.%The aim of this study is to provide the basic for the exploration of Rsgst genes by bioinformatics and gene expression analysis.Based on the R.solani AG1-IA genome database RSIADB,the sequence of Rsgst gene was found.Basic information of the GST amino acid sequence was predicted by several softwares,and a phylogenetic tree was constructed using MEGA 5.0 software.qRT-PCR was used to detect the gene expression levels during the pro-gress of sclerotial development of R.solani AG1-IA,and the GST activity was measured simultaneously.The results showed that the full length of Rsgst was 1 207 bp,and the gene encodes 277 amino acid residues.The molecular weight of GST was 30.90 ku and the theoretical isoelectric point was 9.42.The secondary structure of this protein was mainly consisted by α-helix which accounted for 41.52%.The phylogenetic tree showed that the R.solani GST was more closely related to Sporisorium reilianum GST.qRT-PCR indicated that the expression of Rsgst was upregu-lated during the sclerotial development with the highest gene expression at 60 h,which was 7.64,and the maximal activity of GST was 0.375 U/μg at the 5th day.These results are significant to decipher the functions of Rsgst in R. solani AG1-IA.