title: The quorum sensing-dependent gene katG of Burkholderia glumae is important for protection from visible light.
abstract: Quorum sensing (QS) plays important roles in the pathogenicity of Burkholderia glumae, the causative agent of bacterial rice grain rot. We determined how QS is involved in catalase expression in B. glumae. The QS-defective mutant of B. glumae exhibited less catalase activity than wild-type B. glumae. A beta-glucuronidase assay of a katG::Tn3-gusA78 reporter fusion protein revealed that katG expression is under the control of QS. Furthermore, katG expression was upregulated by QsmR, a transcriptional activator for flagellar-gene expression that is regulated by QS. A gel mobility shift assay confirmed that QsmR directly activates katG expression. The katG mutant produced toxoflavin but exhibited less severe disease than BGR1 on rice panicles. Under visible light conditions and a photon flux density of 61.6 micromol(-1) m(-2), the survival rate of the katG mutant was 10(5)-fold lower than that of BGR1. This suggests that KatG is a major catalase that protects bacterial cells from visible light, which probably results in less severe disease caused by the katG mutant.
authors.affiliation: Department of Agricultural Biotechnology, Seoul National University, Seoul , Republic of Korea.
authors.forename: Heejin
authors.initials: H
authors.lastname: Chun
authors.forename: Okhee
authors.initials: O
authors.lastname: Choi
authors.forename: Eunhye
authors.initials: E
authors.lastname: Goo
authors.forename: Nayeon
authors.initials: N
authors.lastname: Kim
authors.forename: Hongsup
authors.initials: H
authors.lastname: Kim
authors.forename: Yongsung
authors.initials: Y
authors.lastname: Kang
authors.forename: Jinwoo
authors.initials: J
authors.lastname: Kim
authors.forename: Jae Sun
authors.initials: JS
authors.lastname: Moon
authors.forename: Ingyu
authors.initials: I
authors.lastname: Hwang
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics*; D019117:Burkholderia / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism / Q000528:radiation effects*; D024202:Electrophoretic Mobility Shift Assay; D015964:Gene Expression Regulation, Bacterial; D008027:Light; D050296:Microbial Viability / Q000235:genetics* / Q000528:radiation effects*; D009154:Mutation; D012275:Oryza / Q000382:microbiology; D011744:Pyrimidinones / Q000378:metabolism; D053038:Quorum Sensing / Q000235:genetics*; D014227:Triazines / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D011744:Pyrimidinones; D014227:Triazines; C009570:toxoflavin