College of Agriculture, Guangxi University, Nanning, China.
College of Plant Protection, China Agricultural University, Beijing, China.
Appl Environ Microbiol. 2020 Nov 24;86(24). doi: 10.1128/AEM.02016-20.
2P24 is a rhizosphere bacterium that protects many crop plants against soilborne diseases caused by phytopathogens. The PcoI/PcoR quorum-sensing (QS) system and polyketide antibiotic 2,4-diacetylphloroglucinol (2,4-DAPG) are particularly relevant to the strain's biocontrol potential. In this study, we investigated the effects of c-di-GMP on the biocontrol activity of strain 2P24. The expression of the diguanylate cyclase (YedQ) and phosphodiesterase (YhjH) in 2P24 significantly increased and decreased the cellular concentration of c-di-GMP, respectively. The production of the QS signals -acyl homoserine lactones (AHLs) and 2,4-DAPG was negatively regulated by c-di-GMP in 2P24. The regulatory proteins RsmA and RsmE were positively regulated by c-di-GMP. Genomic analysis revealed that 2P24 has 23 predicted proteins that contain c-di-GMP-synthesizing or -degrading domains. Among these proteins, C0J56_12915, C0J56_13325, and C0J56_27925 contributed to the production of c-di-GMP and were also involved in the regulation of the QS signal and antibiotic 2,4-DAPG production in Overexpression of C0J56_12915, C0J56_13325, and C0J56_27925 in 2P24 impaired its root colonization and biocontrol activities. Taken together, these results demonstrated that c-di-GMP played an important role in fine-tuning the biocontrol traits of In various bacteria, the bacterial second messenger c-di-GMP influences a wide range of cellular processes. However, the function of c-di-GMP on biocontrol traits in the plant-beneficial rhizobacteria remains largely unclear. The present work shows that the QS system and polyketide antibiotic 2,4-DAPG production are regulated by c-di-GMP through RsmA and RsmE proteins in 2P24. The diguanylate cyclases (DGCs) C0J56_12915, C0J56_13325, and C0J56_27925 are especially involved in regulating the biocontrol traits of 2P24. Our work also demonstrated a connection between the Gac/Rsm cascade and the c-di-GMP signaling pathway in .
2P24 是一种根际细菌，可保护许多作物植物免受植物病原体引起的土传病害的侵害。群体感应（QS）系统和聚酮类抗生素 2,4-二乙酰基间苯二酚（2,4-DAPG）与该菌株的生物防治潜力特别相关。在这项研究中，我们研究了 c-di-GMP 对菌株 2P24 生物防治活性的影响。2P24 中的二鸟苷酸环化酶（YedQ）和磷酸二酯酶（YhjH）的表达分别显着增加和减少了细胞中二鸟苷酸环化酶的浓度。QS 信号 - 酰基高丝氨酸内酯（AHLs）和 2,4-DAPG 的产生在 2P24 中受 c-di-GMP 负调控。调节蛋白 RsmA 和 RsmE 受 c-di-GMP 正调控。基因组分析表明，2P24 具有 23 种预测蛋白，这些蛋白包含 c-di-GMP 合成或降解结构域。在这些蛋白质中，C0J56_12915、C0J56_13325 和 C0J56_27925 有助于 c-di-GMP 的产生，并且还参与了 QS 信号和抗生素 2,4-DAPG 在 2P24 中的产生的调节。C0J56_12915、C0J56_13325 和 C0J56_27925 在 2P24 中的过表达损害了其根定植和生物防治活性。总之，这些结果表明 c-di-GMP 在微调 2P24 的生物防治特性方面发挥了重要作用。在各种细菌中，细菌第二信使 c-di-GMP 影响广泛的细胞过程。然而，植物有益根际细菌中 c-di-GMP 对生物防治特性的功能在很大程度上尚不清楚。本工作表明，QS 系统和聚酮类抗生素 2,4-DAPG 的产生通过 RsmA 和 RsmE 蛋白在 2P24 中受到 c-di-GMP 的调节。二鸟苷酸环化酶（DGC）C0J56_12915、C0J56_13325 和 C0J56_27925 特别参与调节 2P24 的生物防治特性。我们的工作还证明了 Gac/Rsm 级联和 c-di-GMP 信号通路之间的联系在 中。
