Xanthomonas oryzae pv. oryzae chemotaxis components and chemoreceptor Mcp2 are involved in the sensing of constituents of xylem sap and contribute to the regulation of virulence-associated functions and entry into rice
Xanthomonas oryzae pv. oryzae chemotaxis components and chemoreceptor Mcp2 are involved in the sensing of constituents of xylem sap and contribute to the regulation of virulence-associated functions and entry into rice
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DOI：
10.1111/mpp.12718
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发表时间：
2018-11-01
影响因子：
4.9
通讯作者：
Chatterjee, Subhadeep
中科院分区：
文献类型：
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作者：
Verma, Raj Kumar;Samal, Biswajit;Chatterjee, Subhadeep
植物病原菌的黄单胞菌群在作物中引起几种经济上重要的疾病。在水稻细菌性病原菌中，黄单胞菌水稻条斑病菌（Xanthomonasarpv.）Xoo），已经提出趋化性可能在病原体在宿主内的进入和定殖中起作用。然而，趋化系统的组成部分，包括所涉及的化学受体，以及它们在进入和毒力中的作用，还没有很好的定义。在这项研究中，我们表明Xoo显示出积极的趋化反应，水稻木质部汁液的组分谷氨酰胺，木糖和蛋氨酸。为了了解参与促进趋化性、进入和毒力的趋化性组分的作用，我们进行了详细的缺失突变体分析。缺陷的突变体的趋化性成分，鞭毛生物发生，表达分析和测定的毒力相关功能的分析表明，趋化性介导的信号Xoo参与调节几个毒力相关的功能，如运动，附件和铁稳态。Xoo的增量cheY1突变体表现出参与运动，粘附素，铁的吸收和代谢的基因的表达减少。我们表明，Xoo的趋化性和运动成分的表达诱导下，在植物条件下，所需的进入，殖民和毒力。此外，一个假定的化学感受器mcp 2基因的缺失分析表明，化学感受器mcp 2参与木质部汁液和木质部分泌物的成分，包括蛋氨酸，丝氨酸和组氨酸的传感，并在附生进入和毒力中起着重要作用。这是第一次报告的作用，趋化性的毒力，这一重要的植物病原体。
The Xanthomonas group of phytopathogens causes several economically important diseases in crops. In the bacterial pathogen of rice, Xanthomonas oryzae pv. oryzae (Xoo), it has been proposed that chemotaxis may play a role in the entry and colonization of the pathogen inside the host. However, components of the chemotaxis system, including the chemoreceptors involved, and their role in entry and virulence, are not well defined. In this study, we show that Xoo displays a positive chemotaxis response to components of rice xylem sap-glutamine, xylose and methionine. In order to understand the role of chemotaxis components involved in the promotion of chemotaxis, entry and virulence, we performed detailed deletion mutant analysis. Analysis of mutants defective in chemotaxis components, flagellar biogenesis, expression analysis and assays of virulence-associated functions indicated that chemotaxis-mediated signalling in Xoo is involved in the regulation of several virulence-associated functions, such as motility, attachment and iron homeostasis. The increment cheY1 mutant of Xoo exhibited a reduced expression of genes involved in motility, adhesins, and iron uptake and metabolism. We show that the expression of Xoo chemotaxis and motility components is induced under in planta conditions and is required for entry, colonization and virulence. Furthermore, deletion analysis of a putative chemoreceptor mcp2 gene revealed that chemoreceptor Mcp2 is involved in the sensing of xylem sap and constituents of xylem exudate, including methionine, serine and histidine, and plays an important role in epiphytic entry and virulence. This is the first report of the role of chemotaxis in the virulence of this important group of phytopathogens.