The pltR gene, coding a putative LysR-type regulator, was identified upstream Plt biosynthetic gene cluster in Pseudomonas sp. M18 using bioinformatics technology. The null mutation of pltR resulted in mutant M18TRG (...The pltR gene, coding a putative LysR-type regulator, was identified upstream Plt biosynthetic gene cluster in Pseudomonas sp. M18 using bioinformatics technology. The null mutation of pltR resulted in mutant M18TRG (pltR::Gm) by recombination and its Plt (Pyoluteorin) production declined to 30% while PCA (Phenazine-1-carboxylic acid) production remained unchanged as compared with the wild-type M18 grown in King’s Medium B. After complementation, Plt production of mutant M18TRG was restored to the level in wild-type M18. Overexpression of pltR in M18 led to 13-fold enhancement of Plt produc-tion over the wild-type M18 strain. However, PCA production was unchanged under this condition. These data suggested that PltR was a positive regulator on Plt production. Plt itself, however, could not regulate expression of pltR. Expression of the plt-lacZ transcriptional fusion in mutant M18TRG de-clined obviously as compared with the wild-type M18, which further proved that PltR could regulate expression of Plt biosynthetic genes at the transcriptional level. In addition, the investigation on the pltR expression in gacA mutant M18G and rsmA mutant M18R disclosed that PltR was involved in the positive regulation of gacA on Plt production while being excluded from the negative control caused by rsmA.展开更多
基金Supported by the Science Program of the China National 10th "Five-year Plan" (Grant No. 2004BA308A21-6)the National Natural Science Foundation of China (Grant No. 30370041) and NCET in China
文摘The pltR gene, coding a putative LysR-type regulator, was identified upstream Plt biosynthetic gene cluster in Pseudomonas sp. M18 using bioinformatics technology. The null mutation of pltR resulted in mutant M18TRG (pltR::Gm) by recombination and its Plt (Pyoluteorin) production declined to 30% while PCA (Phenazine-1-carboxylic acid) production remained unchanged as compared with the wild-type M18 grown in King’s Medium B. After complementation, Plt production of mutant M18TRG was restored to the level in wild-type M18. Overexpression of pltR in M18 led to 13-fold enhancement of Plt produc-tion over the wild-type M18 strain. However, PCA production was unchanged under this condition. These data suggested that PltR was a positive regulator on Plt production. Plt itself, however, could not regulate expression of pltR. Expression of the plt-lacZ transcriptional fusion in mutant M18TRG de-clined obviously as compared with the wild-type M18, which further proved that PltR could regulate expression of Plt biosynthetic genes at the transcriptional level. In addition, the investigation on the pltR expression in gacA mutant M18G and rsmA mutant M18R disclosed that PltR was involved in the positive regulation of gacA on Plt production while being excluded from the negative control caused by rsmA.
