马铃薯晚疫病抗性相关基因StDIR1的克隆与表达  

Cloning and Expression of a Potato Dirigent-like Gene(StDIR1) Responsive to Infection by Phytophthora infestans

作　　者：张洪伟[1] 李继刚[1] 郑建坡[1] 曲占良[1] 

机构地区：[1]河北大学生命科学学院,河北保定071002

出　　处：《华北农学报》2012年第2期23-29,共7页Acta Agriculturae Boreali-Sinica

基　　金：河北大学博士基金(2007-097);河北省教育厅资助项目(2007412)

摘　　要：马铃薯是世界性粮蔬作物。致病疫霉引起的晚疫病则是马铃薯育种所面临的最严峻问题之一,因此,分离和利用马铃薯晚疫病抗性基因获得抗病新品种是马铃薯育种的重要目标。首先在连翘中发现的一类与木质素合成相关的Dirigent基因可能在植物抗病虫害过程中起重要作用。试验根据马铃薯的EST序列信息设计特异性引物,并通过RT-PCR和RACE技术获得了一条全长为729 bp的Dirigent基因cDNA序列,命名为StDIR1;该cDNA编码一个包含191个氨基酸的蛋白质多肽;系统进化分析表明,该多肽是一种Dirigent-like蛋白,属于DIR-b亚群,与陆地棉Di-rigent-like protein 1相似性高达76%,同一性为62%。利用半定量RT-PCR技术分析发现,致病疫霉、H2O2以及NO可以诱导该基因不同程度的上调表达。组织特异性分析表明,该基因在马铃薯根组织中表达量最高,而在茎、叶、花以及块茎组织中的表达量偏低。首次表明StDIR1基因与马铃薯对致病疫霉的侵染应答具有相关性。Potato is an important vegetable and food crop all over the world. Potato late blight, caused by Phyto- phthora infestans,is one of the most serious challenges in potato breeding in which an essential method is to isolate the resistance genes and gain the new resistant potato varieties by transgenic technology. Dirigent protein, found in Forsythia suspense firstly, assists the stereoselective bimolecular phenoxy radical ＇coupling in lignan synthesis, and may play an important role in plant resistance against pests and pathogens. Specific primers were designed according to the potato EST sequence, and a 729 bp cDNA,designated StDIR1 ,was cloned by RT-PCR and RACE amplifica- tion,which encodes a peptide composed of 191 amino acids and contains a conservative domain of dirigent proteins. Phylogenetic analysis indicated that the assumption peptide, which shares a similarity of 76% and an identity of 62% with Gossypium hirsutum Dirigent-like protein 1 ,is a Dirigent-like protein and belongs to the DIR-b subfamily. Semi-quantitative RT-PCR analysis indicated that the expression of StDIR1 is up-regulated in different degrees un- der the induction of P. infestans, exogenous~ H202 and NO, respectively. Tissue-specific expression analysis demon- strated a very high expression level of StDIRI in potato root tissue, and a lower level of expression in the tissue of stem,leaf, flower and tuber. This study firstly indicated that the StDIR1 gene is related to the response of potato a- gainst the infection of P. infestans.

关 键 词：Dirigent蛋白质 马铃薯晚疫病 植物抗病 

分 类 号：S432.1[农业科学—植物病理学] Q78[农业科学—农业昆虫与害虫防治]