Pantoea ananatis is a plant pathogenic bacterium that severely impacts rice. In spite of its worldwide prevalence, limited studies have been conducted so far on the control of P. ananatis. Bacitracin A is a non-ribosomal peptide antibiotic with strong antibacterial activity produced by Bacillus licheniformis strain HN-5. We investigated the mechanisms of action underlying the biocontrol and bactericidal efficacy of bacitracin A against P. ananatis. Fluorescence microscopy and bacterial cell viability analyses revealed that the median effective concentration of bacitracin A against P. ananatis was 9.10 μg ml⁻¹. Scanning and transmission electron microscopy showed that bacitracin A damaged the cell wall and membrane of P. ananatis. Quantitative real-time PCR indicated that the transcriptional expression of ftsZ, glmS, and gumD, which are involved in cell division, cell-wall biosynthesis, and extracellular polymeric substance biosynthesis, respectively, was upregulated at 12 h and significantly downregulated at 24 h after bacitracin A treatment in P. ananatis. Bacitracin A caused cell leakage and changes to membrane permeability in P. ananatis, supporting its use as a natural biocontrol agent for P. ananatis.

Pantoea ananatis是一种严重影响水稻的植物致病细菌。尽管它在世界范围内盛行，但迄今为止，对菠萝假单胞菌的控制研究还很有限。杆菌肽A是一种由地衣芽孢杆菌HN-5菌株产生的具有强抗菌活性的非核糖体肽抗生素。我们研究了杆菌肽A对菠萝假单胞菌的生物控制和杀菌效力的作用机制。荧光显微镜和细菌细胞生存力分析表明，杆菌肽A对半数有效浓度P.ananatis中为9.10微克毫升^-1。扫描电子显微镜观察到杆菌肽A破坏了菠萝假单胞菌的细胞壁和细胞膜。实时定量PCR结果表明，分别参与细胞分裂，细胞壁生物合成和细胞外高分子物质生物合成的ftsZ，glmS和gumD的转录表达在12 h后被上调，而在24 h后被显着下调。杆菌肽A治疗凤梨。杆菌肽A引起的细胞泄漏和改变在膜渗透性P.ananatis中，在支撑其使用作为天然生物防除剂P.ananatis中。