玉米大斑病抗性基因Ht1定位区域内候选序列的生物信息学分析

为获得玉米大斑病抗性基因Ht1候选序列, 文章采用生物信息学方法对与玉米大斑病抗性基因Ht1紧密连锁的分子标记umc22和umc122定位区域内候选序列进行了分析, 其中得到的63条ORF序列中有14条序列可编码蛋白质结构域。将14条核苷酸酸序列预测出的氨基酸序列与已克隆的24条抗性基因编码氨基酸序列进行Blast比对及进化树构建。结果发现, 候选序列gpm565a具有植物抗性基因编码产物的高度保守结构域, 而且与抗性基因Xal相似性高、亲缘关系近, 推测可能与抗性基因Ht1有关。其他候选序列由于不具有植物抗性基因编码产物的高度保守结构域或者相似性低、亲缘关系远等原因, 不能确定与抗性基因Ht1有关。通过对候选序列gpm565a进行二级结构及三维结构分析, 发现有大量构成蛋白质特异功能结构组件的无规则卷曲存在, 推测gpm565a可能是Ht1功能域的一部分。

Bioinformatics analysis of candidate sequences between two flanking markers linked with resistance gene Ht1 to Exserohilum turcicum in maize

In order to get Ht1 candidate sequence(s), bioinformatics method was employed to analyze sequences between two flanking markers umc22a and umc122a linked with Ht1. Sixty-three open reading frame (ORF) sequences were found, fourteen of which encoded protein domains. The amino acid sequences encoded by these ORF sequences were blasted with the 24 cloned resistance gene amino acid sequences, and a phylogenetic tree was constructed. Among the fourteen ORF sequences, gpm565a with nucleotide binding site (NBS), containing a lot of random coils, had both high identity and close relationship with Xal resistant to bacterial blight, and was predicted to be related with Ht1. The remaining thirteen ORF sequences had no enough evidence to show any relationships with Ht1 due to lack of conserved domains, low identity or distant relationships.