title: The rsmA-like gene rsmA(Xoo) of Xanthomonas oryzae pv. oryzae regulates bacterial virulence and production of diffusible signal factor.
abstract: The plant-pathogenic prokaryote Xanthomonas oryzae pv. oryzae (Xoo) causes bacterial leaf blight, one of the most destructive diseases of rice. A nonpolar mutant of the rsmA-like gene rsmA(Xoo) of the Xoo Chinese strain 13751 was constructed by homologous integration with a suicide plasmid. Virulence tests on a host plant, namely the hybrid rice cultivar Teyou 63, showed that the mutant had lost its virulence almost completely, whereas tests on a nonhost, namely castor-oil plant (Ricinus communis), showed that the mutant had also lost the ability to induce a hypersensitive response in the nonhost. In addition, the rsmA(Xoo) mutant produced significantly smaller amounts of the diffusible signal factor, extracellular endoglucanase, amylase and extracellular polysaccharide, but showed significantly higher glycogen accumulation, bacterial aggregation and cell adhesion. The expression of most hrp genes, genes encoding AvrBs3/PthA family members, rpfB, xrvA, glgA, eglXoB and XOO0175 (encoding an α-amylase) was down-regulated in the rsmA(Xoo) mutant. All phenotypes and expression levels of the tested genes in the rsmA(Xoo) mutant were restored to their levels in the wild-type by the presence of rsmA(Xoo) in trans. These results indicate that rsmA(Xoo) is essential for the virulence of Xoo.
authors.affiliation: Guangxi Key Laboratory of Subtropical Bioresource Conservation and Utilization, Key Laboratory of Ministry of Education for Microbial and Plant Genetic Engineering, College of Life Science and Technology, Guangxi University, 100 Daxue Road, Nanning, Guangxi 530004, China.
authors.forename: Pei-Liang
authors.initials: PL
authors.lastname: Zhu
authors.forename: Shuai
authors.initials: S
authors.lastname: Zhao
authors.forename: Ji-Liang
authors.initials: JL
authors.lastname: Tang
authors.forename: Jia-Xun
authors.initials: JX
authors.lastname: Feng
mesh_terms: D000681:Amylases / Q000096:biosynthesis; D001422:Bacterial Adhesion / Q000235:genetics; D001426:Bacterial Proteins / Q000096:biosynthesis* / Q000235:genetics*; D002480:Cellulase / Q000096:biosynthesis; D004058:Diffusion; D005110:Extracellular Space / Q000201:enzymology; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial / Q000235:genetics*; D006003:Glycogen / Q000096:biosynthesis; D012275:Oryza / Q000382:microbiology; D011135:Polysaccharides, Bacterial / Q000096:biosynthesis; D014774:Virulence / Q000235:genetics; D014974:Xanthomonas / Q000201:enzymology / Q000235:genetics* / Q000472:pathogenicity*
chemical_list: D001426:Bacterial Proteins; D011135:Polysaccharides, Bacterial; D006003:Glycogen; D000681:Amylases; D002480:Cellulase