title: Identification, characterization and regulation of two secreted polygalacturonases of the emerging rice pathogen Burkholderia glumae.
abstract: Burkholderia glumae is an emerging seed-borne rice pathogen in many areas around the world. Previous studies have demonstrated that B. glumae produces two major virulence factors: the phytotoxin toxoflavin and a secreted lipase. This synthesis of both of these factors is regulated by an N-acyl homoserine lactone (AHL)-dependent, cell-density-dependent quorum-sensing regulation system. This study reports the production and secretion of two highly similar endo-polygalacturonases (designated PehA and PehB) by B. glumae. The two enzymes were purified to homogeneity and the corresponding genetic determinants were identified and characterized. When either polygalacturonase gene was inactivated, B. glumae retained rice virulence comparable to that of the wild-type parent strain. Furthermore, the role of AHL-dependent quorum sensing and of plant cell wall degradation compounds in their regulation was investigated.
authors.affiliation: Bacteriology Group, International Centre for Genetic Engineering and Biotechnology, Padriciano, Trieste, Italy.
authors.forename: Giuliano
authors.initials: G
authors.lastname: Degrassi
authors.forename: Giulia
authors.initials: G
authors.lastname: Devescovi
authors.forename: Jinwoo
authors.initials: J
authors.lastname: Kim
authors.forename: Ingyu
authors.initials: I
authors.lastname: Hwang
authors.forename: Vittorio
authors.initials: V
authors.lastname: Venturi
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D019117:Burkholderia / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development / Q000472:pathogenicity; D003001:Cloning, Molecular; D015964:Gene Expression Regulation, Bacterial; D015971:Gene Expression Regulation, Enzymologic; D008969:Molecular Sequence Data; D012275:Oryza / Q000382:microbiology*; D010935:Plant Diseases / Q000382:microbiology*; D011096:Polygalacturonase / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D053038:Quorum Sensing; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA
chemical_list: D001426:Bacterial Proteins; D011096:Polygalacturonase