Zhou Min, Gao Kexiang, Zeng Jun, Yu Xiaoli, Wu Yan, Ge Jun, Duan Yunfei, Liu Xiaoguang
Institute of Life Sciences, Jiangsu University, Zhenjiang 212013, China.
Front Biosci (Elite Ed). 2012 Jan 1;4(4):1263-75. doi: 10.2741/457.
The RNA-binding protein Hfq has been well studied as a global post-transcriptional regulator which controls diverse cellular processes in bacteria. However, the function in the genus of Serratia has remained unexplored. Here we show that beyond mutation in Hfq resulting in their growth defects, Hfq has global effects on a variety of biocontrol-related phenotypes in the endophytic strain G3 of Serratia plymuthica, including antifungal activity, production of exoenzymes, as well as motility and biofilm formation. Especially for the first time, Hfq is observed to control biosynthesis of auxin indole-3-acetic acid (IAA) and antibiotic pyrrolnitrin (PRN), which are key determinants responsible for plant growth promotion and suppression of phytopathogens, respectively by G3. Additionally, Hfq is also required for the production of RpoS, a major stress sigma factor in G3. In contrast to E. coli, translation of hfq in G3 is positively autoregulated. Further investigation of the molecular mechanisms involved in regulation of IAA and pyrrolnitrin production by Hfq and its role in the regulatory networks of G3 will help to optimize the beneficial plant-microbe interactions.
RNA结合蛋白Hfq作为一种全局性转录后调节因子已得到深入研究，它可控制细菌中的多种细胞过程。然而，其在沙雷氏菌属中的功能仍未被探索。在此我们表明，除了Hfq突变会导致其生长缺陷外，Hfq对粘质沙雷氏菌内生菌株G3中多种与生物防治相关的表型具有全局性影响，包括抗真菌活性、胞外酶产生以及运动性和生物膜形成。特别是首次观察到Hfq可控制生长素吲哚 - 3 - 乙酸（IAA）和抗生素吡咯菌素（PRN）的生物合成，它们分别是G3促进植物生长和抑制植物病原体的关键决定因素。此外，Hfq也是G3中主要应激σ因子RpoS产生所必需的。与大肠杆菌不同，G3中hfq的翻译受到正向自调控。进一步研究Hfq调控IAA和吡咯菌素产生的分子机制及其在G3调控网络中的作用，将有助于优化有益的植物 - 微生物相互作用。
