Department of Plant Pathology, University of California, Davis, CA 95616, U.S.A.
Department of Microbiology & Molecular Genetics, University of California, Davis, CA 95616, U.S.A.
Mol Plant Microbe Interact. 2021 Nov;34(11):1307-1315. doi: 10.1094/MPMI-05-21-0124-R. Epub 2021 Nov 3.
Upon encountering a susceptible plant host, a bacterial pathogen expresses specific virulence factors. For example, in planta, the HrpX protein activates transcription of roughly 150 genes encoding components of the type III secretion system or its translocated effectors, as well as other secreted proteins implicated in pathogenesis. Here, we show that pv. growth in planta or in HrpX-inducing XOM2 media resulted in HrpX-dependent transcription of the and genes that control production of the RaxX sulfopeptide, exported through a type I secretion system. The RaxX protein is required for activation of XA21-mediated immunity in rice lines. We identified potential plant-inducible promoter elements upstream of the likely 5' ends of the and transcripts. Deletions and nucleotide substitutions confirmed that these elements are required for HrpX-dependent expression of and . We conclude that gene expression is induced by HrpX during growth in planta and, therefore, is coordinately expressed with other genes required for pathogenesis.[Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
当遇到易感植物宿主时，细菌病原体表达特定的毒力因子。例如，在植物体内，HrpX 蛋白激活约 150 个基因的转录，这些基因编码 III 型分泌系统或其易位效应物的组成部分，以及其他与发病机制相关的分泌蛋白。在这里，我们表明 pv. 在植物体内或在诱导 HrpX 的 XOM2 培养基中生长，导致控制 RaxX 硫肽产生的 和 基因的 HrpX 依赖性转录，该硫肽通过 I 型分泌系统输出。RaxX 蛋白是激活 水稻系中 XA21 介导免疫所必需的。我们鉴定了可能的植物诱导启动子元件，位于 和 转录物的可能 5'端上游。缺失和核苷酸取代证实这些元件是 HrpX 依赖表达 和 的必需条件。我们得出结论， 在植物体内生长过程中被 HrpX 诱导表达，因此与发病机制所需的其他基因协调表达。[公式：见正文] 版权所有 © 2021 作者。这是一个在 CC BY-NC-ND 4.0 国际许可下发布的开放获取文章。
