Pseudomonas fluorescens 2P24 is a plant-beneficial rhizobacteria that controls many root diseases caused by soil-borne pathogens, and the production of the antibiotic compound 2,4-diacetylphloroglucinol (2,4-DAPG) is essential for its biocontrol ability. In the present study, we investigated the regulatory mechanism acting on the production of 2,4-DAPG by the GacA-dependent small non-coding RNAs (sRNAs) and RsmA/E proteins in strain 2P24. Our results showed that the GacS-GacA system regulates the expression of the phlACBD locus, which is responsible for 2,4-DAPG production, by inducing the expression of rsmX, rsmX1, rsmY, and rsmZ. A novel GacA-regulated sRNA, RgsA, was found to negatively regulate 2,4-DAPG production. Activation of the phlACBD locus by the GacS-GacA system is mediated through RsmA and RsmE proteins (but not RsmI), which inhibit phlACBD translation by binding to the putative RsmA/E recognition element in the phlACBD leader. Taken together, our results suggested that in P. fluorescens 2P24, the GacS-GacA system controls the cellular 2,4-DAPG levels in the cell by fine-tuning the function of sRNAs in P. fluorescens.

荧光假单胞菌2P24是一种植物有益的根瘤菌，可控制由土壤传播的病原体引起的许多根部疾病，而抗生素化合物2,4-二乙酰基间苯三酚（2,4-DAPG）的产生对于其生物防治能力至关重要。在本研究中，我们调查了2P24菌株中GacA依赖性小非编码RNA（sRNA）和RsmA / E蛋白对2,4-DAPG产生的调控机制。我们的结果表明，GacS-GacA系统通过诱导rsmX，rsmX1，rsmY和rsmZ的表达来调节负责2,4-DAPG产生的phlACBD基因座的表达。。发现一种新型的GacA调节的sRNA RgsA负调节2，4-DAPG的产生。所述的活化phlACBD由GACS-GACA系统轨迹通过RSMA和RSME蛋白（但不RsmI），其介导的抑制phlACBD翻译通过结合在推定RSMA / E识别元件phlACBD领导者。两者合计，我们的结果表明，在荧光假单胞菌2P24中，GacS-GacA系统通过微调荧光假单胞菌中sRNA的功能来控制细胞中细胞中2,4-DAPG的水平。