摘要
荧光假单胞菌SF39a是从小麦根际分离的植物生长促进细菌。在这份报告中，我们证明这种天然菌株分泌抑制假单胞菌属和黄单胞菌属植物病原菌株生长的细菌素。在菌株SF39a的基因组中检测到S型pyocin基因并命名为pys。构建了非极性的pys :: Km突变体。细菌素生产受损在这个突变体。

为了鉴定涉及细菌素调控的基因，进行随机转座子诱变。称为荧光假单胞菌SF39a-451的miniTn5Km1突变体显示细菌素生产强烈降低。该表型是由编码磷相关磷酸转移酶系统（PTSNtr）的磷酸烯醇丙酮酸磷酸转移酶（EINtr）的ptsP基因的失活引起的。此外，与野生型菌株相比，该突变体显示出生物膜形成和蛋白酶生产的减少，以及表面运动性和pyoverdine产量的增加。此外，我们研究了菌株SF39a-451在温室条件下定殖小麦根际的能力。有趣的是，突变体在根际的竞争性低于野生型菌株。据我们所知，这项研究首次提供了ptsP基因在细菌素生产中的相关性和荧光假单胞菌中py素S的功能表征。
Pseudomonas fluorescens SF39a is a plant-growth-promoting bacterium isolated from wheat rhizosphere. In this report, we demonstrate that this native strain secretes bacteriocins that inhibit growth of phytopathogenic strains of the genera Pseudomonas and Xanthomonas. An S-type pyocin gene was detected in the genome of strain SF39a and named pys. A non-polar pys::Km mutant was constructed. The bacteriocin production was impaired in this mutant.
To identify genes involved in bacteriocin regulation, random transposon mutagenesis was carried out. A miniTn5Km1 mutant, called P. fluorescens SF39a-451, showed strongly reduced bacteriocin production. This phenotype was caused by inactivation of the ptsP gene which encodes a phosphoenolpyruvate phosphotransferase (EINtr) of the nitrogen-related phosphotransferase system (PTSNtr). In addition, this mutant showed a decrease in biofilm formation and protease production, and an increase in surface motility and pyoverdine production compared with the wild-type strain. Moreover, we investigated the ability of strain SF39a-451 to colonize the wheat rhizosphere under greenhouse conditions. Interestingly, the mutant was less competitive than the wild-type strain in the rhizosphere. To our knowledge, this study provides the first evidence of both the relevance of the ptsP gene in bacteriocin production and functional characterization of a pyocin S in P. fluorescens.

https://www.sciencedirect.com/science/article/pii/S092325081500203X