Characterization of the multiple molecular mechanisms underlying RsaL control of phenazine-1-carboxylic acid biosynthesis in the rhizosphere bacterium Pseudomonas aeruginosa PA1201.
Phenazines are important secondary metabolites that have been found to affect a broad spectrum of organisms. Two almost identical gene clusters phz1 and phz2 are responsible for phenazines biosynthesis in the rhizobacterium Pseudomonas aeruginosa PA1201. Here, we show that the transcriptional regulator RsaL is a potent repressor of phenazine-1-carboxylic acid (PCA) biosynthesis. RsaL negatively regulates phz1 expression and positively regulates phz2 expression via multiple mechanisms. First, RsaL binds to a 25-bp DNA region within the phz1 promoter to directly repress phz1 expression. Second, RsaL indirectly regulates the expression of both phz clusters by decreasing the activity of the las and pqs quorum sensing (QS) systems, and by promoting the rhl QS system. Finally, RsaL represses phz1 expression through the downstream transcriptional regulator CdpR. RsaL directly binds to the promoter region of cdpR to positively regulate its expression, and subsequently CdpR regulates phz1 expression in a negative manner. We also show that RsaL represents a new mechanism for the turnover of the QS signal molecule N-3-oxododecanoyl-homoserine lactone (3-oxo-C12-HSL). Overall, this study elucidates RsaL control of phenazines biosynthesis and indicates that a PA1201 strain harboring deletions in both the rsaL and cdpR genes could be used to improve the industrial production of PCA.
State Key Laboratory of Microbial Metabolism, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China.
Shuang
S
Sun
State Key Laboratory of Microbial Metabolism, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China.
Bo
B
Chen
State Key Laboratory of Microbial Metabolism, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China.
Zi-Jing
ZJ
Jin
State Key Laboratory of Microbial Metabolism, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China.
Lian
L
Zhou
State Key Laboratory of Microbial Metabolism, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China.
Yun-Ling
YL
Fang
Department of Biology, Faculty of Science, King Mongkut's Institute of Technology Ladkrabang, Bangkok, Thailand.
Chitti
C
Thawai
Department of Science, University Roma Tre, Rome, Italy.
Giordano
G
Rampioni
State Key Laboratory of Microbial Metabolism, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China.
Ya-Wen
http://orcid.org/0000-0002-7349-924X
YW
He
D015107:4-Butyrolactone / Q000031:analogs & derivatives / Q000378:metabolism; D001419:Bacteria / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D015964:Gene Expression Regulation, Bacterial / Q000235:genetics; D006714:Homoserine / Q000031:analogs & derivatives / Q000378:metabolism; D010619:Phenazines / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000235:genetics; D011550:Pseudomonas aeruginosa / Q000235:genetics; D053038:Quorum Sensing / Q000235:genetics / Q000502:physiology; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D058441:Rhizosphere
D001426:Bacterial Proteins; C109860:N-(3-oxododecanoyl)homoserine lactone; D010619:Phenazines; D012097:Repressor Proteins; C118377:rsaL protein, Pseudomonas aeruginosa; C037165:1-phenazinecarboxylic acid; D006714:Homoserine; D015107:4-Butyrolactone