RsmB调控普城沙雷氏菌硝吡咯菌素的生物合成

RsmB Involved in Modulation of the Pyrrolnitrin Biosynthesis in Serratia plymuthica

摘要: 研究表明γ–变形杆菌中的Csr/Rsm家族小RNA主要在转录后水平参与全局调控基因表达、控制多种生物学过程，以及调节细菌运动性和生物膜形成等社会行为，并参与调控氢氰酸和酚嗪等抗生素的生物合成。本研究使用内生菌普城沙雷氏菌野生菌株G3及其小RNA突变株ΔrsmB为试验菌株，组合表型突变分析、定性TLC层析和LC-MS定量分析，检测了抗生素硝吡咯菌素PRN和群体感应信号分子N-乙酰基高丝氨酸内酯AHL (N-acylhomoserine lactone)的合成水平。结果表明G3菌株RsmB小RNA作为全局调控子可正向控制PRN和AHL产生，以及蛋白酶活性和生物膜的形成。首次证明RsmB小RNA可通过影响AHL介导的群体感应系统，分别在转录和转录后水平上调控PRN生物合成水平。为进一步通过操纵细菌Rsm系统遗传改良生防菌提供了新策略。

Abstract: The Csr/Rsm-family small RNAs (sRNAs) have been established as major post-transcriptional regulators of gene expression in γ-proteobacteria, implicated in a variety of biological process and social behavior such as cell motility, biofilm formation, especially the biosynthesis pathway of several antibiotics such as hydrogen cyanide and phenazines. However, whether they affect production of the antibiotic pyrrolnitrin remains unclear. In this work, using the endophytic Serratia plymuthica wild type G3 and its RsmB mutant as model strains, mutational analysis of pyrrolnitrin production, antifungal activity and other phenotypes, combined with TLC bioassay of AHL production demonstrated for the first time that in S. plymuthica G3, RsmB functions as a pleiotropic regulator to be involved in controlling the pyrrolnitrin biosynthesis at both transcriptional and translational levels via affecting the globally transcriptional regulation system such as quorum sensing at least. In addition, RsmB also upregulated antifungal activity accordingly, along with protease and biofilm formation. This will help get some insight into the role of the Rsm system in pyrrolnitrin biosynthesis.