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

Front. Microbiol. | doi: 10.3389/fmicb.2019.01991

Malate-Dependent Carbon Utilization Enhances Central Metabolism and Contributes to Biological Fitness of Laribacter hongkongensis via CRP Regulation

 Patrick C. Woo1, 2, 3, 4, 5*,  Lifeng Xiong1, 6,  Elaine Chan1,  L.L. J. TENG1, Siguo Liu6 and Susanna K. Lau1, 2, 3, 4, 5
  • 1Department of Microbiology, The University of Hong Kong, Hong Kong
  • 2Research Centre of Infection and Immunology, University of Hong Kong, Hong Kong
  • 3State Key Laboratory of Emerging Infectious Diseases, University of Hong Kong, China
  • 4Carol Yu Centre for Infection, University of Hong Kong, China
  • 5Collaborative Innovation Center for Infectious Diseases Diagnosis and Treatment, University of Hong Kong, China
  • 6Division of Bacterial Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agriculture, China

Metabolic adaptation in various environmental niches is crucial for bacterial extracellular survival and intracellular replication during infection. However, the metabolism of carbon/nitrogen sources and related regulatory mechanisms in Laribacter hongkongensis, an asaccharolytic bacterium associated with invasive infections and gastroenteritis, are still unknown. In present study, we demonstrated that malate can be exploited as preferred carbon source of L. hongkongensis. Using RNA-sequencing, we compared the transcriptional profiles of L. hongkongensis cultivated with/without malate supplementation, and observed that malate utilization significantly inhibits the use of alternative carbon sources while enhancing respiratory chain as well as central carbon, sulfur and urease-mediated nitrogen metabolisms. The tight connection among these important metabolic pathways indicates that L. hongkongensis is capable of integrating information from different metabolism branches to coordinate the expression of metabolic genes and thereby adapt to environmental changing. Furthermore, we identified that a transcription factor, CRP, is repressed by malate-mediated metabolism while negatively regulating the effect of malate on these central metabolic pathways. Remarkably, CRP also responds to various environmental stresses, influences the expression of other transcription factors, and contributes to the biological fitness of L. hongkongensis. The regulatory network and cross-regulation enables the bacteria to make the appropriate metabolic responses and environmental adaptation.

Keywords: Metabolism, biological fitness, crp, regulation, adaptation, Malate, Laribacter hongkongensis

Received: 04 Jun 2019; Accepted: 13 Aug 2019.

Edited by:

Ulrike Kappler, University of Queensland, Australia

Reviewed by:

Armen Trchounian, Yerevan State University, Armenia
Feng-Biao Guo, University of Electronic Science and Technology of China, China  

Copyright: © 2019 Woo, Xiong, Chan, TENG, Liu and Lau. 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: Prof. Patrick C. Woo, The University of Hong Kong, Department of Microbiology, Pokfulam, Hong Kong, pcywoo@hkucc.hku.hk