Department of Microbiology and Plant Pathology, University of California, Riverside, CA 92521, U.S.A.
USDA Agricultural Research Service, San Joaquin Valley Agricultural Sciences Center, Parlier, CA 93648, U.S.A.
Mol Plant Microbe Interact. 2023 Oct;36(10):636-646. doi: 10.1094/MPMI-03-23-0027-R. Epub 2023 Oct 25.
is a xylem-limited bacterial pathogen that causes Pierce's disease (PD) of grapevine. In host plants, this bacterium exclusively colonizes the xylem, which is primarily non-living at maturity. Understanding how interfaces with this specialized conductive tissue is at the forefront of investigation for this pathosystem. Unlike many bacterial plant pathogens, lacks a type III secretion system and cognate effectors that aid in host colonization. Instead, utilizes plant cell-wall hydrolytic enzymes and lipases as part of its xylem colonization strategy. Several of these virulence factors are predicted to be secreted via the type II secretion system (T2SS), the main terminal branch of the Sec-dependent general secretory pathway. In this study, we constructed null mutants in and , which encode for the ATPase that drives the T2SS and the major structural pseudopilin of the T2SS, respectively. Both mutants were non-pathogenic and unable to effectively colonize grapevines, demonstrating that the T2SS is required for infection processes. Furthermore, we utilized mass spectrometry to identify type II-dependent proteins in the secretome. In vitro, we identified six type II-dependent proteins in the secretome that included three lipases, a β-1,4-cellobiohydrolase, a protease, and a conserved hypothetical protein. [Formula: see text] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
是一种木质部限制的细菌病原体，可引起葡萄的皮尔氏病（PD）。在宿主植物中，这种细菌专门定殖在木质部，木质部在成熟时主要是非活的。了解 如何与这种特化的导组织相互作用是该病理系统研究的前沿。与许多细菌性植物病原体不同， 缺乏有助于宿主定殖的 III 型分泌系统和同源效应物。相反， 利用植物细胞壁水解酶和脂肪酶作为其木质部定殖策略的一部分。这些毒力因子中的几个据预测通过 II 型分泌系统（T2SS）分泌，T2SS 是 Sec 依赖的一般分泌途径的主要末端分支。在这项研究中，我们构建了 和 的缺失突变体，它们分别编码驱动 T2SS 的 ATP 酶和 T2SS 的主要结构假菌毛。这两个突变体都没有致病性，也不能有效地定殖葡萄藤，表明 T2SS 是 感染过程所必需的。此外，我们利用质谱法鉴定了 分泌体中的 II 型依赖性蛋白。在体外，我们在分泌体中鉴定出六种依赖 II 型的蛋白质，其中包括三种脂肪酶、一种 β-1,4-纤维素酶、一种蛋白酶和一种保守的假设蛋白。 [公式：见正文] 版权所有©2023 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。
