花生HIR基因的克隆表达与进化分析

Cloning,Expression and Evolution Analysis of Peanut HIR Gene

过敏性反应是植物抗病机制中最常见的形式之一。过敏性诱导反应(Hypersensitive-induced reaction)基因HIR是与过敏反应相关的一类基因,属于PID家族成员,参与许多细胞生理过程,并与细胞程序化死亡有密切关系。本研究从花生转录组文库中筛选到编码HIR基因的部分序列,通过5'-RACE获得花生HIR基因的全长cDNA序列,并克隆了其基因组序列。分析表明,花生HIR基因与其他物种HIR基因具有高度同源性。对6个物种共17条HIR序列使用最大似然法进行进化分析表明,该基因在进化中受到了强烈的纯化选择作用。qRT-PCR分析发现,该基因的表达量在冷处理4 h时显著降低,随着处理时间延长其表达量逐渐回升;在病菌处理的材料中该基因的表达下调。这些结果为进一步研究HIR基因在花生抗病、耐逆中的功能奠定了基础。

Hypersensitive response （HR）is one of the most common forms of resistant mechanism in plants.The hypersensitive-induced reaction gene HIR,belonging to PID family,plays an important role in hypersensitive response.It participates in many cellular processes,and has close relations with programmed cell death.In this study,a partial sequence of HIR gene was obtained from peanut transcriptome library.The full-length cDNA was acquired by 5′-RACE amplification and the genomic sequence was also cloned.Bioinfor-matics analysis showed that peanut HIR gene was highly homologous with that of other species.Seventeen HIR genes belonging to 6 species were selected for phylogenetic analysis by maximum likelihood method.PAML software analysis demonstrated that HIR gene suffered strong purified selection during evolution.The quantita-tive RT-PCR results showed that the expression level of AhHIR was significantly decreased after treated at 4℃for 4 hours,and then gradually increased with the increase of treating time.The pathogenic bacteria infec-tion also caused a down-regulated expression of this gene.These results laid foundations for further functional studies of AhHIR in disease and stress resistances of peanut.