中国板栗EST-SNP和抗栗疫病候选基因分析及同源比对

从壳斗科基因组数据库下载中国板栗的Unigene序列和基于这些Unigene序列开发获得的EST-SNP数据,分析发现,中国板栗EST-SNP的发生频率为4个/kb,在碱基置换类型上,C-T置换发生的频率最高,C-G置换发生频率最低,转换和颠换的比值为1.74∶1.对211个在中国板栗健康组织和感染栗疫病的染病组织中差异表达的基因进行基因注释和蛋白质结构域分析,结果表明,参与蛋白质代谢、对胁迫、生物和非生物刺激发生响应的基因所占的比例较多,并发现了大量的跨膜结构、信号肽、卷曲螺旋和蛋白激酶相关结构域.对这211个中国板栗抗栗疫病相关的候选基因和其Unigene序列进行同源比对,统计整理定位在具有同源性的Unigene序列上的EST-SNP,共有3023个EST-SNP标记.这批EST-SNP标记可为今后开展基于候选基因途径的中国板栗抗栗疫病居群基因组学研究和关联作图研究奠定重要的基础.

Characteristic Analysis and Homology Alignment of EST-SNPs and Candidate Genes for Chestnut Blight Resistance of Castanea mollissima

Unigene sequences and EST-SNPs derived from Castanea mollissima were downloaded from the Fagaceae Genomics database（www.fagaceae.org）.The EST-SNP frequency in those unigenes was 1 SNP per 251 bp.For substitution types of those EST-SNPs,C-T substitution was the most frequent mutation type,accounting for 31.84% of all EST-SNPs,while C-G substitution occurred most rarely,accounting for only 5.76% of all EST-SNPs.The ratio of transition to transversion was 1.74 ∶1.Gene ontology for 211 differentially expressed genes in chestnut blight fungus（Cryphonectria parasitica） infected vs healthy stem tissues of Castanea mollissima were investigated.Except for other cellular and metabolic processes,protein meta-bolism,response to stress,and response to abiotic or biotic stimulus were among the most represented biological process categories.Many transmembrane domains,signal peptides,coiled coil regions,and Pkinase related domains were found from analysis of protein sequences of the 211 differentially expressed genes.Using TBLASTX,the 211 differentially expressed genes were compared to all unigene sequences of Castanea mollissima.The EST-SNPs located on the homologous unigene sequences were summarized and resulted in a total of 3023 EST-SNPs.These EST-SNP markers provide insights into the studies of population genomics and association mapping for chestnut blight resistance in Castanea mollissima.