小麦病程相关蛋白1基因的克隆及特征分析

Cloning and Characterization of Pathogenesis-related Protein 1 from Wheat-H.villosa Translocation Lines

利用ＲＴ－ＰＣＲ技术，从被白粉菌诱导的小麦－簇毛麦６ＶＳ／６ＡＬ易位系中获得病程相关蛋 白１（ＴａＰｒ－１）。ＤＮＡ克隆．该基因具有编码１６４氨基酸的开放阅读框，其中包含２４个氨基酸构 成的信号肽和１４０个氨基酸组成的成熟肽（ＭＷ为１５．１ｋＤ）．经蛋白结构比较分析，发现其与 植物中已分离的多种 ＰＫ类蛋白具一定的同源性。 Ｎｏｒｔｈｅｒｎ杂交显示，易位系被诱导 １２小时 左右，该基因转录物累积最多，其在抗病易位系和感病亲本扬５中表达水平有明显差异。 Ｓｏｕｔｈｅｒｎ杂交表明在小麦基因组中该基因的拷贝数多于１个，且该基因在扬５和易位系中表 现多态性，表明６ＶＳ上有可能携带该基因。

A Triticum aestivum-Haynaldia villosa 6VS/6AL translocation line contained powdery mildew resistance gene Pm21 which is effective against all the current biotypes of Erygsiphe gramins. Cloning of the related genes for powdery mildew resistance is significance for understanding its resistance mechansism and disease resistance breeding. Using RT-PCR and RACE technology, a wheat pathogenesis related protein I cDNA clone (TaPr-1) corresponding to a mRNA differentially induced in resistant 6VS/6AL translocation line compared to susceptible wheat cultivar 'Yangmai 5' by powdery mildew infection was isolated and characterized. This sequence contained 823bp and had an open reading frame (ORF containing 164 amino acids with 24 amino acids in the putative signal peptide and 140 amino acids comprising the mature peptide (15.1kD). The deduced amino acid sequence showed close homology to PR-1 like proteins, which have been isolated from many plants. Northern blot analysis revealed the most abundantly accumulation of the corresponding mRNA 12h after infection in translocation line (6VS /6AL). The obviously difference in the expression of the PRw-1 was also observed between resistant translocation line (6VS/6AL) and susceptible parent 'Yangmai 5', it showed the TaPr-1 gene is related tO powdery mildew resistance. Southern blot indicated that the wheat genome contains more than one copies of TaPr-1 genes, and there are polymorphism between translocation lines and 'Yanmai 5',the result shows that 6VS may contain TaPr-1 genes.