Coronatine Gene Expression In Vitro and In Planta, and Protein Accumulation During Temperature Downshift in Pseudomonas syringae

Sensors

Yvonne Braun¹  Angela V. Smirnova¹  Helge Weingart¹  Alexander Schenk¹ 

[1] Jacobs University Bremen, School of Engineering and Science, Campus Ring 1, 28759 Bremen, Germany; E-Mails:

关键词: COR;    coronatine;    TCS;    two-component system;    HPK;    histidine protein kinase;    RR;    response regulator;   

DOI  :  10.3390/s90604272

来源: mdpi

【 摘 要 】

The plant pathogenic bacterium Pseudomonas syringae PG4180 synthesizes high levels of the phytotoxin coronatine (COR) at the virulence-promoting temperature of 18 °C, but negligible amounts at 28 °C. Temperature-dependent COR gene expression is regulated by a modified two-component system, consisting of a response regulator, CorR, the histidine protein kinase CorS, and a third component, termed CorP. We analyzed at transcriptional and translational levels the expression of corS and the cma operon involved in COR biosynthesis after a temperature downshift from 28 to 18 °C. Expression of cma was induced within 20 min and increased steadily whereas corS expression was only slightly temperature-dependent. Accumulation of CmaB correlated with accumulation of cma mRNA. However, cma transcription was suppressed by inhibition of de novo protein biosynthesis. A transcriptional fusion of the cma promoter to a promoterless egfp gene was used to monitor the cma expression in vitro and in planta. A steady induction of cma::egfp by temperature downshift was observed in both environments. The results indicate that PG4180 responds to a temperature decrease with COR gene expression. However, COR gene expression and protein biosynthesis increased steadily, possibly reflecting adaptation to long-term rather than rapid temperature changes.

【 授权许可】

CC BY   
© 2009 by the authors; licensee Molecular Diversity Preservation International, Basel, Switzerland.