title: A systematic analysis of the role of GGDEF-EAL domain proteins in virulence and motility in Xanthomonas oryzae pv. oryzicola.
abstract: The second messenger c-di-GMP is implicated in regulation of various aspects of the lifestyles and virulence of Gram-negative bacteria. Cyclic di-GMP is formed by diguanylate cyclases with a GGDEF domain and degraded by phosphodiesterases with either an EAL or HD-GYP domain. Proteins with tandem GGDEF-EAL domains occur in many bacteria, where they may be involved in c-di-GMP turnover or act as enzymatically-inactive c-di-GMP effectors. Here, we report a systematic study of the regulatory action of the eleven GGDEF-EAL proteins in Xanthomonas oryzae pv. oryzicola, an important rice pathogen causing bacterial leaf streak. Mutational analysis revealed that XOC_2335 and XOC_2393 positively regulate bacterial swimming motility, while XOC_2102, XOC_2393 and XOC_4190 negatively control sliding motility. The ΔXOC_2335/XOC_2393 mutant that had a higher intracellular c-di-GMP level than the wild type and the ΔXOC_4190 mutant exhibited reduced virulence to rice after pressure inoculation. In vitro purified XOC_4190 and XOC_2102 have little or no diguanylate cyclase or phosphodiesterase activity, which is consistent with unaltered c-di-GMP concentration in ΔXOC_4190. Nevertheless, both proteins can bind to c-di-GMP with high affinity, indicating a potential role as c-di-GMP effectors. Overall our findings advance understanding of c-di-GMP signaling and its links to virulence in an important rice pathogen.
authors.affiliation: Department of Plant Pathology and the Ministry of Agriculture Key Laboratory for Plant Pathology, China Agricultural University, Beijing, China.
authors.forename: Chao
authors.initials: C
authors.lastname: Wei
authors.affiliation: Department of Plant Pathology and the Ministry of Agriculture Key Laboratory for Plant Pathology, China Agricultural University, Beijing, China.
authors.forename: Wendi
authors.initials: W
authors.lastname: Jiang
authors.affiliation: Department of Plant Pathology and the Ministry of Agriculture Key Laboratory for Plant Pathology, China Agricultural University, Beijing, China.
authors.forename: Mengran
authors.initials: M
authors.lastname: Zhao
authors.affiliation: Department of Plant Pathology and the Ministry of Agriculture Key Laboratory for Plant Pathology, China Agricultural University, Beijing, China.
authors.forename: Junjie
authors.initials: J
authors.lastname: Ling
authors.affiliation: Department of Plant Pathology and the Ministry of Agriculture Key Laboratory for Plant Pathology, China Agricultural University, Beijing, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Zeng
authors.affiliation: Department of Plant Pathology and the Ministry of Agriculture Key Laboratory for Plant Pathology, China Agricultural University, Beijing, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Deng
authors.affiliation: Department of Plant Pathology and the Ministry of Agriculture Key Laboratory for Plant Pathology, China Agricultural University, Beijing, China.
authors.forename: Dongli
authors.initials: D
authors.lastname: Jin
authors.affiliation: School of Microbiology, BioSciences Institute, University College Cork, Cork, Ireland.
authors.forename: John Maxwell
authors.initials: JM
authors.lastname: Dow
authors.affiliation: Department of Plant Pathology and the Ministry of Agriculture Key Laboratory for Plant Pathology, China Agricultural University, Beijing, China.
authors.forename: Wenxian
authors.initials: W
authors.lastname: Sun
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D006152:Cyclic GMP / Q000031:analogs & derivatives / Q000378:metabolism; D004252:DNA Mutational Analysis; D015964:Gene Expression Regulation, Bacterial; D012275:Oryza / Q000382:microbiology; D017434:Protein Structure, Tertiary; D015398:Signal Transduction; D014774:Virulence; D014974:Xanthomonas / Q000378:metabolism / Q000472:pathogenicity* / Q000502:physiology
chemical_list: D001426:Bacterial Proteins; C062025:bis(3',5')-cyclic diguanylic acid; D006152:Cyclic GMP