Wei Tong, Chern Mawsheng, Liu Furong, Ronald Pamela C
Department of Plant Pathology and the Genome Center, University of California, Davis, Davis, CA, 95616, USA.
Feedstocks Division, Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
Mol Plant Pathol. 2016 Dec;17(9):1493-1498. doi: 10.1111/mpp.12368. Epub 2016 Apr 13.
The rice XA21 receptor kinase confers robust resistance to bacterial blight disease caused by Xanthomonas oryzae pv. oryzae (Xoo). A tyrosine-sulfated peptide from Xoo, called RaxX, triggers XA21-mediated immune responses, including the production of ethylene and reactive oxygen species and the induction of defence gene expression. It has not been tested previously whether these responses confer effective resistance to Xoo. Here, we describe a newly established post-inoculation treatment assay that facilitates investigations into the effect of the sulfated RaxX peptide in planta. In this assay, rice plants were inoculated with a virulent strain of Xoo and then treated with the RaxX peptide 2 days after inoculation. We found that post-inoculation treatment of XA21 plants with the sulfated RaxX peptide suppresses the development of Xoo infection in XA21 rice plants. The treated plants display restricted lesion development and reduced bacterial growth. Our findings demonstrate that exogenous application of sulfated RaxX activates XA21-mediated immunity in planta, and provides a potential strategy for the control of bacterial disease in the field.
水稻XA21受体激酶赋予对由稻黄单胞菌稻致病变种（Xoo）引起的白叶枯病的强大抗性。一种来自Xoo的酪氨酸硫酸化肽，称为RaxX，触发XA21介导的免疫反应，包括乙烯和活性氧的产生以及防御基因表达的诱导。此前尚未测试过这些反应是否赋予对Xoo的有效抗性。在此，我们描述了一种新建立的接种后处理试验，该试验有助于研究硫酸化RaxX肽在植物中的作用。在该试验中，用水稻白叶枯病菌的强毒株接种水稻植株，然后在接种后2天用RaxX肽处理。我们发现，对接种后的XA21植株用硫酸化RaxX肽处理可抑制XA21水稻植株中Xoo感染的发展。处理后的植株表现出病斑发展受限和细菌生长减少。我们的研究结果表明，外源施用硫酸化RaxX可激活植物中XA21介导的免疫，并为田间细菌性病害的防治提供了一种潜在策略。
