Impact Factor 4.019
2017 JCR, Clarivate Analytics 2018

The world's most-cited Microbiology journal

Original Research ARTICLE Provisionally accepted The full-text will be published soon. Notify me

Front. Microbiol. | doi: 10.3389/fmicb.2019.01230

LbDSF, the Lysobacter brunescens Quorum Sensing System Diffusible Signalling Factor, Regulates Anti-Xanthomonas XSAC Biosynthesis, Colony Morphology, and Surface Motility

 Jun Ling1*, Runjie Zhu1,  Pedro Laborda2, Tianping Jiang1, Yifan Jia1,  YANGYANG ZHAO1 and  Fengquan Liu1*
  • 1Institute of Plant Protection, Jiangsu Key Laboratory for Food Quality and Safety-State Key Laboratory Cultivation Base of Ministry of Science and Technology, Jiangsu Academy of Agricultural Sciences (JAAS), China
  • 2School of Life Sciences, Nantong University, China

Lysobacter species are emerging as novel sources of antibiotics, but the regulation of these antibiotics has not been thoroughly elucidated to date. In this work, we identified a small diffusible signalling factor (DSF) molecule (LbDSF) that regulates the biosynthesis of a novel Xanthomonas-specific antibiotic compound(s) (XSAC) in Lysobacter brunescens OH23. LbDSF was isolated from the culture broth of L. brunescens OH23, and the chemical structure of the molecule was determined by NMR and MS. The LbDSF compound induced GUS expression in a reporter strain of Xanthomonas campestris pv. campestris FE58, which contained the gus gene under the control of a DSF-inducible engXCA promoter. LbDSF production was found to be linked to the enoyl-CoA hydratase RpfF and dependent on the two-component regulatory system RpfC (hybrid sensor histidine kinase)/RpfG (response regulator), and LbDSF production was increased 6.72 times in the ΔrpfC compared to wild-type OH23. LbDSF-regulated XSAC production was dramatically decreased in ΔrpfF, ΔrpfC, and ΔrpfG. Additionally, a significant reduction in surface motility and a number of changes in colony morphology were observed in the ΔrpfF, ΔrpfC, and ΔrpfG compared to the wild-type OH23. The exogenous LbDSF significantly increased XSAC production in wild-type OH23 and recovered the XSAC biosynthetic ability in ΔrpfF. Taken together, these results showed that LbDSF is a fatty acid-derived DSF that positively regulates XSAC biosynthesis, cell morphology, and surface motility. Moreover, the RpfC/RpfG quorum sensing signal transduction pathway mediates XSAC biosynthesis. These findings may facilitate antibiotic production through genetic engineering in Lysobacter spp.

Keywords: diffusible signaling factor, anti-Xanthomonas compound, colony morphology, Surface motility, Lysobacter brunescens

Received: 14 Feb 2019; Accepted: 17 May 2019.

Edited by:

Cristina García-Aljaro, University of Barcelona, Spain

Reviewed by:

Meriyem Aktas, Ruhr University Bochum, Germany
Shaohua Chen, South China Agricultural University, China  

Copyright: © 2019 Ling, Zhu, Laborda, Jiang, Jia, ZHAO and Liu. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence:
Dr. Jun Ling, Jiangsu Academy of Agricultural Sciences (JAAS), Institute of Plant Protection, Jiangsu Key Laboratory for Food Quality and Safety-State Key Laboratory Cultivation Base of Ministry of Science and Technology, Nanjing, China, robinlingjun@126.com
Prof. Fengquan Liu, Jiangsu Academy of Agricultural Sciences (JAAS), Institute of Plant Protection, Jiangsu Key Laboratory for Food Quality and Safety-State Key Laboratory Cultivation Base of Ministry of Science and Technology, Nanjing, China, fqliu20011@sina.com