玉米抗病相关基因NPR1的同源克隆及表达分析

Cloning and expression analysis of the disease-related gene NPR1 in maize

NPR1是植物系统获得性(systemic acquired resistance,SAR)抗病反应中的关键基因,对植物的广谱抗性起重要调控作用。以玉米自交系"齐319"为材料,通过PCR方法克隆到一个玉米NPR1基因(命名为Zm NPR1)。序列分析结果显示Zm NPR1包含两个保守结构域POZ/BTB位点和Ankyrin repeat锚蛋白重复位点。蛋白质聚类分析表明Zm NPR1与水稻Os NPR2的同源性最高。亚细胞定位结果显示Zm NPR1定位于洋葱表皮细胞的细胞核中。半定量PCR结果显示,Zm NPR1和玉米防卫基因PAL(编码苯丙氨酸解氨酶)响应水杨酸、玉米矮花叶病毒和玉米小斑病原菌的诱导并显著上调表达;而Zm NPR1和PAL的表达水平受到茉莉酸甲酯的明显抑制。这表明Zm NPR1在玉米中参与到水杨酸介导的抗病反应通路。

The NPR1 gene plays a key role in systemic acquired resistance（SAR） and provides broad-spectrum resistance in plants. In this study, the NPR1 gene was cloned from the maize inbred line ＂Qi 319＂ based on PCR technique and was named as Zm NPR1. Sequence analysis exhibited two conserved POZ/BTB domains and an ankyrin repeat domain in the Zm NPR1 protein. Phylogenetic analysis showed that Zm NPR1 was high homology with rice Os NPR2. Transient expression of the Zm NPR1-GFP fusion protein in onion skin cells showed a nuclear localization of Zm NPR1. RT-q PCR showed that expression of Zm NPR1 and the gene PAL, which encodes a pathogenesis-related protein, were induced by the treatment of salicylic acid（SA）, Maize mosaic virus and Maize Helminthosporium maydis, whereas the expression level of Zm NPR1 was inhibited by methyl jasmonate. Taken together, these results suggest that the Zm NPR1 gene plays an important role in the SA-meditated disease resistance pathway in maize.