葡萄座腔菌(Botryosphaeria dothidea)全基因组分泌蛋白的预测及功能分析

 葡萄座腔菌(Botryosphaeria dothidea)是引起多种果树和林木枝干溃疡病和果实腐烂病的重要病原菌。为明确葡萄座腔菌的致病机理,采用SignalP、WoLF PSORT、TMHMM、GPI-SOM等软件,对葡萄座腔菌全基因组14 998条蛋白序列进行了分泌蛋白预测和功能分析。结果表明B.dothidea全基因组编码蛋白中有851条序列具有典型的分泌蛋白特征,占蛋白总数的5.67%,其长度主要分布在100~700个氨基酸范围内。信号肽的分析结果表明,以19个氨基酸为信号肽的分泌蛋白数目最多,非极性氨基酸丙氨酸(A)在信号肽中的使用频率最高,而有带电侧链的天冬氨酸(D)和谷氨酸(E)使用频率最低,信号肽-3和-1位置的氨基酸相对保守,其切割位点属于典型的A-X-A型。对分泌蛋白功能预测结果表明,578个分泌蛋白获得了功能注释,其功能主要涉及碳水化合物的运输、代谢过程,蛋白翻译后修饰和氨基酸代谢、运输过程。分泌蛋白中效应蛋白(effector)预测结果表明,B. dothidea分泌蛋白中共有119个潜在的效应蛋白,其中11个可被PHI数据库注释到,其与引起其他植物病原菌致病力变化的致病效应蛋白具有较高的相似性。碳水化合物活性酶类(CAZymes)的预测结果表明,B. dothidea分泌蛋白组中共有279个CAZymes,其中GHs家族最多。这些结果的获得为今后进一步筛选B. dothidea的效应蛋白,明确B. dothidea的致病机理,以及筛选寄主新的抗性基因提供了必要的基础。

Genome-wide prediction and analysis of the secreted proteins of Botryosphaeria dothidea

Botryosphaeria dothidea is an important pathogen that causes cankers on woods trunk and fruits rot on fruit trees. To investigate molecular mechanisms of the fungal pathogenicity, secreted proteins of B. dothidea were predicted based on the genome-wide protein sequences consisting of 14 998 sequences by combined using SignalP, WoLF PSORT, TMHMM, and GPI-SOM softwares. The results showed that 851 sequences with classical secreted protein characteristics were predicted to be secreted proteins, accounting for 5.67% of the total ones. The lengths of the secreted proteins were concentrated in the range of 100-700 amino acids. The results of signal peptides analysis showed that the most frequent amino acid in signal peptides is nonpolar alanine (A), while the least amino acids are aspartic acid (D) and glutamic acid (E) with an electric side-chain. The amino acids in the position -3 and -1 are very conserved. The signal peptide cleavage site belongs to the typical A-X-A type. Among the putative 851 secreted proteins, 578 ones were functionally annotated to involve in carbohydrate transport and metabolism, posttranslational modification, amino acid transport and metabolism. The effector prediction results indicated that 119 secreted proteins might serve as potential effectors, among which 11 ones can be functionally annotated in the PHI database and have higher homology with the pathogenicity-related proteins in other pathogenic fungi. The CAZymes prediction results showed that 279 ones among B. dothidea putative secreted proteins were carbohydrate-active enzymes, dominated by glycoside hydrolase superfamily (GHs). These findings pave the way for screening effector proteins and new resistant genes in different hosts and insight into the pathogenesis of B.dothiea.