This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Google Scholar
Right arrow Articles by Huang, J.
Right arrow Articles by Zhang, X.
PubMed
Right arrow PubMed Citation
Right arrow Articles by Huang, J.
Right arrow Articles by Zhang, X.
Agricola
Right arrow Articles by Huang, J.
Right arrow Articles by Zhang, X.

 Previous Article  |  Next Article 

Applied and Environmental Microbiology, October 2009, p. 6568-6580, Vol. 75, No. 20
0099-2240/09/$08.00+0     doi:10.1128/AEM.01148-09
Copyright © 2009, American Society for Microbiology. All Rights Reserved.

Temperature-Dependent Expression of phzM and Its Regulatory Genes lasI and ptsP in Rhizosphere Isolate Pseudomonas sp. Strain M18{triangledown}

Jiaofang Huang, Yuquan Xu,* Hongyan Zhang, Yaqian Li, Xianqing Huang, Bin Ren, and Xuehong Zhang

Key Laboratory of Microbial Metabolism, Ministry of Education, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China

Received 18 May 2009/ Accepted 16 August 2009

Pseudomonas sp. strain M18, an effective biological control agent isolated from the melon rhizosphere, has a genetic background similar to that of the opportunistic human pathogen Pseudomonas aeruginosa PAO1. However, the predominant phenazine produced by strain M18 is phenazine-1-carboxylic acid (PCA) rather than pyocyanin (PYO); the quantitative ratio of PCA to PYO is 105 to 1 at 28°C in strain M18, while the ratio is 1 to 2 at 37°C in strain PAO1. We first provided evidence that the differential production of the two phenazines in strains M18 and PAO1 is related to the temperature-dependent and strain-specific expression patterns of phzM, a gene involved in the conversion of PCA to PYO. Transcriptional levels of phzM were measured by quantitative real-time PCR, and the activities of both transcriptional and translational phzM'-'lacZ fusions were determined in strains M18 and PAO1, respectively. Using lasI::Gm and ptsP::Gm inactivation M18 mutants, we further show that expression of the phzM gene is positively regulated by the quorum-sensing protein LasI and negatively regulated by the phosphoenolpyruvate phosphotransferase protein PtsP. Surprisingly, the lasI and ptsP regulatory genes were also expressed in a temperature-dependent and strain-specific manner. The differential production of the phenazines PCA and PYO by strains M18 and PAO1 may be a consequence of selective pressure imposed on P. aeruginosa PAO1 and its relative M18 in the two different niches over a long evolutionary process.

* Corresponding author. Mailing address: School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, 800 Dongchuan Rd., Shanghai 200240, People's Republic of China. Phone and fax: 86-21-34204854. E-mail: xuyq{at}sjtu.edu.cn

{triangledown} Published ahead of print on 28 August 2009.

Applied and Environmental Microbiology, October 2009, p. 6568-6580, Vol. 75, No. 20
0099-2240/09/$08.00+0     doi:10.1128/AEM.01148-09
Copyright © 2009, American Society for Microbiology. All Rights Reserved.





Copyright © 2009 by the American Society for Microbiology.   For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»