title: StoS, a hybrid histidine kinase sensor of Xanthomonas oryzae pv. oryzae, is activated by sensing low O₂ concentration and is involved in stress tolerance and virulence.
abstract: Bacteria have two-component signal transduction systems (TCSTS), which are important devices for receiving various environmental signals. A TCSTS generally consists of a sensor histidine kinase (HK) and a response regulator (RR) that contains a receiver domain. There are also hybrid-type HK (HyHK) that comprise a HK with a receiver domain within one molecule. In this study, we show that the deletion mutant of a HyHK XOO_0635 (StoS) of Xanthomonas oryzae pv. oryzae, the causal agent of bacterial leaf blight of rice, had decreased stress tolerance to high osmolarity, sodium, and H₂O₂. Growth of the StoS mutant was delayed, and viability was lower than the wild type in medium and in rice leaves. We found that StoS regulates the expression of various genes including XOO_3715, XOO_0131, and stoS itself. A domain search revealed a PAS domain with a heme pocket in StoS, implying that the HyHK functions as an O₂ sensor. When the bacteria were incubated in low oxygen, the StoS-dependent expression of XOO_0131 and XOO_3715 became higher. Therefore, StoS is activated by sensing a low O2 concentration in its environs and is involved in gene expression for adapting to various stressful conditions.
authors: Yumi
authors: Y
authors: Ikawa
authors: Ayako
authors: A
authors: Furutani
authors: Hirokazu
authors: H
authors: Ochiai
authors: Seiji
authors: S
authors: Tsuge
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D017930:Genes, Reporter; D000071677:Histidine Kinase; D054884:Host-Pathogen Interactions; D006861:Hydrogen Peroxide / Q000378:metabolism; D012275:Oryza / Q000382:microbiology*; D009994:Osmolar Concentration; D010100:Oxygen / Q000378:metabolism*; D010935:Plant Diseases / Q000382:microbiology*; D018515:Plant Leaves / Q000382:microbiology; D011494:Protein Kinases / Q000235:genetics* / Q000378:metabolism; D017434:Protein Structure, Tertiary; D017384:Sequence Deletion; D015398:Signal Transduction; D013312:Stress, Physiological; D014774:Virulence; D014974:Xanthomonas / Q000201:enzymology* / Q000235:genetics / Q000472:pathogenicity / Q000502:physiology
chemical_list: D001426:Bacterial Proteins; D006861:Hydrogen Peroxide; D011494:Protein Kinases; D000071677:Histidine Kinase; D010100:Oxygen