背景回顾：Reactive oxygen species (ROS) are vital for plant immunity and regulation of their production is crucial for plant health. 

提出问题：While the mechanisms that elicit ROS production have been relatively well studied, those that repress ROS generation are less well understood. 

结果1-短柄草筛库：Here, via screening Brachypodium distachyon RNA interference (RNAi) mutants, we identified BdWRKY19 as a negative regulator of ROS generation whose knockdown confers elevated resistance to the rust fungus Puccinia brachypodii. 

结果2-小麦同源基因：The three wheat paralogous genes TaWRKY19 are induced during infection by virulent P. striiformis f. sp. tritici (Pst) and have partially redundant roles in resistance. 

结果3-过表达和突变表型：The stable overexpression of TaWRKY19 in wheat increased susceptibility to an avirulent Pst race, while mutations in all three TaWRKY19 copies conferred strong resistance to Pst by enhancing host plant ROS accumulation. 

结果4-TaWRKY19抑制TaNOX10转录：We show that TaWRKY19 is a transcriptional repressor that binds to a W-box element in the promoter of TaNOX10, which encodes an NADPH oxidase and is required for ROS generation and host resistance toPst. 

结论：Collectively, our findings reveal that TaWRKY19 compromises wheat resistance to the fungal pathogen and suggest TaWRKY19 as a potential target to improve wheat resistance to the commercially important wheat stripe rust fungus.

 摘 要 

活性氧物质ROS对于植物的免疫是非常重要的，对于ROS的调控有助于植物的健康生长。尽管目前对于诱导ROS产生机制的研究已经很透彻了，但是对于一直ROS生成的机制研究还很少。本文中，通过对短柄草RNAi突变体库的筛库，作者鉴定到了一个ROS生成的负调控因子BdWRKY19，该基因的敲低会赋予植株更高的锈菌（Puccinia brachypodii）抗性。在小麦中，存在3个TaWRKY19旁系同源基因，均会受到条锈菌（P. striiformis f. sp. tritici，Pst）侵染的诱导表达，在条锈菌抗性功能方面存在冗余。在水稻中稳定过表达TaWRKY19基因能够增强植株对于无毒条锈菌菌株的易感性，而将3个TaWRKY19拷贝全部突变则会通过增强寄主植株的ROS积累，赋予植株极强的条锈菌抗性。作者发现，TaWRKY19是一个转录抑制因子，能够结合到TaNOX10基因启动子上的W-box元件，而TaNOX10基因编码的NADPH氧化酶是ROS生成和条锈菌抗性所必需的蛋白。综上，本文的研究结果揭示了小麦TaWRKY19负调控小麦对于真菌病害的抗性，表明TaWRKY19是未来小麦提高对条锈菌抗性这一重要商业性状的潜在靶标。

 通讯作者 

** 王晓杰 **