title: Identification of new regulatory genes involved in the pathogenic functions of the rice-pathogenic bacterium Burkholderia glumae.
abstract: Burkholderia glumae is an emerging plant-pathogenic bacterium that causes disease in rice in several of the major rice-producing areas throughout the world. In the southern United States, B. glumae is the major causal agent of bacterial panicle blight of rice and has caused severe yield losses in recent decades. Despite its importance, few management options are available for diseases caused by B. glumae, and knowledge of how this pathogen causes disease is limited. In an effort to identify novel factors that contribute to the pathogenicity of B. glumae, random mutagenesis using the miniTn5gus transposon was performed on two strains of B. glumae. Resultant mutants were screened in the laboratory for altered phenotypes in various known or putative virulence factors, including toxoflavin, lipase and extracellular polysaccharides. Mutants that exhibited altered phenotypes compared to their parent strain were selected and subsequently characterized using a PCR-based method to identify the approximate location of the transposon insertion. Altogether, approximately 20 000 random mutants were screened and 51 different genes were identified as having potential involvement in the production of toxoflavin, lipase and/or extracellular polysaccharide. Especially, two regulatory genes, ntpR and tepR, encoding a LysR-type transcriptional regulator and a σ54-dependent response regulator, respectively, were discovered in this study as new negative regulatory factors for the production of toxoflavin, the major phytotoxin synthesized by B. glumae and involved in bacterial pathogenesis.
authors.affiliation: Present address: Mississippi State University, Central Mississippi Research and Extension Center, 1320 Seven Springs Road, Raymond, MS 39154, USA.|Department of Plant Pathology and Crop Physiology, Louisiana State University Agricultural Center, 302 Life Sciences Building, Baton Rouge, Louisiana 70803, USA.
authors.forename: Rebecca A
authors.initials: RA
authors.lastname: Melanson
authors.affiliation: Department of Plant Pathology and Crop Physiology, Louisiana State University Agricultural Center, 302 Life Sciences Building, Baton Rouge, Louisiana 70803, USA.
authors.forename: Inderjit
authors.initials: I
authors.lastname: Barphagha
authors.affiliation: Present address: Department of Agricultural Economics, Louisiana State University, Baton Rouge, LA 70803, USA.|Department of Plant Pathology and Crop Physiology, Louisiana State University Agricultural Center, 302 Life Sciences Building, Baton Rouge, Louisiana 70803, USA.
authors.forename: Surendra
authors.initials: S
authors.lastname: Osti
authors.affiliation: Department of Plant Pathology and Crop Physiology, Louisiana State University Agricultural Center, 302 Life Sciences Building, Baton Rouge, Louisiana 70803, USA.
authors.forename: Tiago P
authors.initials: TP
authors.lastname: Lelis
authors.affiliation: Present address: The Sainsbury Laboratory, Norwich Research Park, Norwich, NR4 7UH, UK.|Department of Plant Pathology and Crop Physiology, Louisiana State University Agricultural Center, 302 Life Sciences Building, Baton Rouge, Louisiana 70803, USA.
authors.forename: Hari S
authors.initials: HS
authors.lastname: Karki
authors.affiliation: Present address: Center for Public Health Genomics, School of Medicine, University of Virginia, Charlottesville, VA 22908, USA.|Department of Plant Pathology and Crop Physiology, Louisiana State University Agricultural Center, 302 Life Sciences Building, Baton Rouge, Louisiana 70803, USA.
authors.forename: Ruoxi
authors.initials: R
authors.lastname: Chen
authors.affiliation: Present address: Citrus Research and Education Center, Department of Microbiology and Cell Sciences, University of Florida, 700 Experiment Station Road, Lake Alfred, FL 33850, USA.|Department of Plant Pathology and Crop Physiology, Louisiana State University Agricultural Center, 302 Life Sciences Building, Baton Rouge, Louisiana 70803, USA.
authors.forename: Bishnu K
authors.initials: BK
authors.lastname: Shrestha
authors.affiliation: Department of Plant Pathology and Crop Physiology, Louisiana State University Agricultural Center, 302 Life Sciences Building, Baton Rouge, Louisiana 70803, USA.
authors.forename: Jong Hyun
authors.initials: JH
authors.lastname: Ham
mesh_terms: D001483:Base Sequence; D019117:Burkholderia / Q000235:genetics* / Q000254:growth & development / Q000472:pathogenicity*; D004251:DNA Transposable Elements / Q000235:genetics*; D004269:DNA, Bacterial / Q000235:genetics; D015964:Gene Expression Regulation, Bacterial / Q000235:genetics; D005809:Genes, Regulator / Q000235:genetics; D008049:Lipase / Q000235:genetics; D016296:Mutagenesis; D009154:Mutation / Q000235:genetics; D012275:Oryza / Q000382:microbiology*; D010641:Phenotype; D010935:Plant Diseases / Q000382:microbiology*; D011135:Polysaccharides, Bacterial / Q000235:genetics; D011744:Pyrimidinones / Q000378:metabolism*; D053038:Quorum Sensing / Q000235:genetics*; D017422:Sequence Analysis, DNA; D014227:Triazines / Q000378:metabolism*; D037521:Virulence Factors / Q000235:genetics
chemical_list: D004251:DNA Transposable Elements; D004269:DNA, Bacterial; D011135:Polysaccharides, Bacterial; D011744:Pyrimidinones; D014227:Triazines; D037521:Virulence Factors; C009570:toxoflavin; D008049:Lipase