MISC

2009年6月

Expression of hrpG and activation of response regulator HrpG are controlled by distinct signal cascades in Ralstonia solanacearum

JOURNAL OF GENERAL PLANT PATHOLOGY
  • Takeshi Yoshimochi
  • ,
  • Yong Zhang
  • ,
  • Akinori Kiba
  • ,
  • Yasufumi Hikichi
  • ,
  • Kouhei Ohnishi

75
3
開始ページ
196
終了ページ
204
記述言語
英語
掲載種別
DOI
10.1007/s10327-009-0157-1
出版者・発行元
SPRINGER TOKYO

The transcriptional regulator HrpB activates the entire hrp regulon in the plant pathogen Ralstonia solanacearum. Through a complex multigene regulatory cascade PrhA-PrhR/PrhI-PrhJ-HrpG, expression of hrpB is induced in a hrp-inducing, nutrient-poor medium and in response to contact between the bacterium and plant cell. In this study, we analyzed the expression levels of these regulatory genes and hrpB using lacZ reporter strains grown in three different conditions: in a nutrient-rich or nutrient-poor medium and co-cultivated with Arabidopsis thaliana seedlings. We found that prhA and prhIR were expressed constitutively. Expression of prhJ and hrpG was PrhA-dependent in all three conditions. Despite the high level of hrpG expression in all cases, hrpB was induced only when the bacteria were co-cultivated with A. thaliana seedlings or grown in nutrient-poor medium. A mutation in the predicted phosphorylation site of hrpG greatly reduced the function of HrpG. From these results, we conclude that the prhA-dependent regulatory cascade controls the expression of hrpG, and a new cascade, which is induced by a signal from plant cells, activates HrpG by phosphorylation. Only when both signal cascades are effective is full expression of hrpB induced. We speculate that the metabolic status of the bacteria in the nutrient-poor medium also contributes to the second cascade.

リンク情報
DOI
https://doi.org/10.1007/s10327-009-0157-1
Web of Science
https://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=JSTA_CEL&SrcApp=J_Gate_JST&DestLinkType=FullRecord&KeyUT=WOS:000266386300006&DestApp=WOS_CPL
ID情報
  • DOI : 10.1007/s10327-009-0157-1
  • ISSN : 1345-2630
  • Web of Science ID : WOS:000266386300006

エクスポート
BibTeX RIS