Verma, Raj Kumar and Samal, Biswajit and Chatterjee, Subhadeep (2018) Xanthomonas oryzae pv. oryzae chemotaxis components and chemoreceptor Mcp2 is involved in sensing constituent of xylem sap and contribute to regulation of virulence associated functions and entry into rice. Molecular Plant Pathology, 19 (11). pp. 2397-2415. ISSN 1464-6722

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Abstract

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 chemoteceptor involved, and their role in entry and virulence is not well defined. In this study we show that Xoo displayed a positive chemotaxis response to components of rice xylem sap, glutamine, xylose, methionine. In order to understand the role of chemotaxis components involved in promoting 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 signaling in Xoo is involved in the regulation of several viriulence associated functions such as motility, attachment and iron homeostasis. The ∆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 are induced under in planta condition and is required for entry, colonization and virulence. Furthermore, deletion analysis of a putative chemoreceptor mcp2 gene revealed that chemoreceptor Mcp2 is involved in sensing 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.

Item Type:	Article
Depositing User:	Users 2 not found.
Date Deposited:	20 Jul 2018 07:52
Last Modified:	16 Nov 2018 19:13
URI:	http://cdfd.sciencecentral.in/id/eprint/855

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