CmMLO2：一个与甜瓜白粉病感病相关的新基因

CmMLO2:A Novel Gene Closely Associated with the Powdery Mildew in Melon

通过RT-PCR方法从甜瓜中克隆得到白粉病感病相关基因CmMLO2的cDNA序列,GenBank登录号为FJ713542。该基因ORF全长1713bp,可编码由570个氨基酸组成的蛋白质,具有7个跨膜螺旋结构,属于典型的跨膜蛋白。RT-PCR结果表明,CmMLO2主要在甜瓜叶片中表达,具有组织特异性。在受到白粉病菌胁迫时CmMLO2表达显著上调,表明CmMLO2很有可能与白粉病发病有关。构建RNAi表达载体pFGC1008-CmMLO2后,利用叶盘转化法转化甜瓜,获得了PCR阳性植株,白粉病接种鉴定结果表明,转化植株对白粉病具有抗性,证明通过ihpRNAi敲除CmMLO2,可以获得对白粉病具有抗性的甜瓜材料。

The full-length cDNA sequence of the MLO gene was cloned via RACE-PCR from muskmelon （ Cucumis melo L. ）, and was designated as CmMLO2 （GenBank Accession No. F J713542） .The gene is 1 713 bp long and encodes a 570-amino acid peptide with a seven-transmembrane domain topology, and is a typical transmembrane protein. Its expression pattern was analyzed using quantitativereal-time PCR after the melon leaf was infected with powdery mildew. The results indicate that CmMLO2 is mainly expressed in melon leaves in a tissue-specific distribution. Moreover, CmMLO2 may play acrucial role in the pathogenesis of powdery mildew. After the efficient of dsRNA constructs were examined via pFGC 1008-CmMLO2 were introduced into Agrobacterium tumefaciens and transformed intomelon wild type with the methods of Agrobacterium-mediated leaf disc transformation. The material of broad-spectrum powdery mildew resistance against P. xanthii in muskmelon was obtained byihpRNAi-mediated knock-down of CmMLO2.