The emergence of antibiotic resistant bacterial strains demands the development of new antimicrobial agents. In the last decades, bacteriocins have gained significant interest due to their potential application as biopreservatives in the food industry and as therapeutic agents in medicine. Recent studies project the use of these antimicrobials in agriculture as biocontrol agents. The characterization of bacteriocins and their genetic regulation, however, have been scarcely studied in plant-associated bacteria. In this report, an in-silico and proteomic analysis was performed to identify the bacteriocins produced by Pseudomonas fluorescens SF4c. More than one functional bacteriocin was detected in this strain (S-type bacteriocins and phage-tail-like bacteriocins [tailocins]). It is known that the regulator PrtR represses bacteriocin production in P. aeruginosa under normal condition. However, the mechanism for tailocin regulation remains unknown in plant-associated pseudomonads. In this work, an orthologue of the prtR of P. aeruginosa was identified in the SF4c-tailocin cluster and a prtR null mutant constructed. The expression and production of tailocins was abolished in this mutant; thus evidencing that, unlike P. aeruginosa, PrtR is a positive regulator of tailocins expression in P. fluorescens.

中文翻译：

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植物相关的假单胞菌菌株中细菌素和PrtR调节剂的表征。

抗生素抗性细菌菌株的出现要求开发新的抗微生物剂。在过去的几十年中，细菌素由于其在食品工业中作为生物防腐剂和在医学中作为治疗剂的潜在应用而获得了广泛的关注。最近的研究预测在农业中使用这些抗微生物剂作为生物防治剂。然而，很少在植物相关细菌中研究细菌素的特征及其遗传调控。在此报告中，进行了计算机内和蛋白质组分析，以鉴定荧光假单胞菌SF4c产生的细菌素。在该菌株中检测到一种以上的功能细菌素（S型细菌素和噬菌体尾状细菌素[tailocins]）。已知调节剂PrtR抑制P中细菌素的产生。正常情况下的铜绿。然而，在与植物相关的假单胞菌中，尾巴素调节的机制仍然未知。在这项工作中，在SF4c-tailocin簇中鉴定了铜绿假单胞菌prtR的直向同源物，并构建了prtR null突变体。在该突变体中消除了tailocins的表达和产生；因此证明，与铜绿假单胞菌不同，PrtR是荧光假单胞菌中tailocins表达的正调节剂。