水稻OsWRKY42是Xa21介导的抗白叶枯病途径新元件

Xa21对白叶枯病菌(Xanthomonas oryzae pv. oryzae, Xoo)具有广谱抗性, 是最早被克隆的水稻(Oryza sativa)抗白叶枯病基因。前期研究表明, OsWRKY42可能在Xa21介导的抗病反应中发挥作用。在Xa21基因遗传背景下制备了OsWRKY42的RNA干扰株系, 将经免疫印迹确认的转基因株系接种白叶枯病菌, 结果表明, 与抗病对照4021相比, 转基因株系的病斑长度增加, 说明OsWRKY42的丰度下调抑制了Xa21对白叶枯病的抗性反应。免疫印迹分析表明, 在OsWRKY42-RNAi转基因水稻中, OsPR6、OsPR15和OsPR16的蛋白质丰度降低, OsPR1A、OsPR1B、OsPR2和OsPR10A的蛋白质丰度升高, 表明这些病程相关蛋白质可能位于OsWRKY42基因的下游, 受OsWRKY42调控并参与Xa21介导的抗病性。研究结果表明, OsWRKY42是Xa21介导的抗白叶枯病途径新元件, 增进了对Xa21介导的水稻抗病机理的认识。

Rice OsWRKY42 is a Novel Element in Xa21-mediated Resistance Pathway Against Bacterial Leaf Blight

Xa21 was the earliest resistant gene cloned in rice, which has broad-spectrum resistance to Xanthomonas oryzae pv. oryzae (Xoo). Our previous study demonstrated that, OsWRKY42 might play a role in Xa21-mediated resistance pathway. In this study, OsWRKY42-RNA interference (OsWRKY42-RNAi) transgenic rice were generated under the background of Xa21, Western blot (WB) verified transgenic plants were used to inoculate Xoo, it was found that the lesion length was longer than that resistance control 4021 (carrying Xa21 gene), indicating that the down-regulation of OsWRKY42 protein abundance impaired Xa21-mediated resistance. In OsWRKY42-RNAi transgenic rice, it was also found by WB analysis that the abundance of OsPR6, OsPR15 and OsPR16 protein were decreased, while the abundance of OsPR1A, OsPR1B, OsPR2 and OsPR10A protein were increased, implying that these pathogenesis-related proteins were regulated by OsWRKY42 and play roles in Xa21-medicated resistance to Xoo at the downstream of OsWRKY42. In conclusion, the results showed that OsWRKY42 is a novel element in Xa21-mediated resistance pathway against Xoo and enhanced our understanding for the mechanism of rice Xa21-mediated resistance.