Affiliation:
1. CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences , Qingdao, China
2. CAS Center for Ocean Mega-Science, Chinese Academy of Sciences , Qingdao, China
3. Laboratory for Marine Biology and Biotechnology, National Laboratory for Marine Science and Technology (Qingdao) , Qingdao, China
Abstract
ABSTRACT
Edwardsiella tarda
is a severe fish pathogen, featured by its capacity to live inside host phagocytes. For intracellular survival, it is crucial for
E. tarda
to neutralize the deleterious effect of host reactive oxygen species (ROS). Accumulating evidence suggests that bacterial metabolism is closely connected to oxidative resistance. However, the roles of
E. tarda
metabolic proteins in antioxidative adaptation and intracellular proliferation remain elusive. In this study, we performed a proteomic analysis on
E. tarda
and identified 111 proteins responsive to H
2
O
2
-mediated oxidative stress. Based on this data, we further obtained eight crucial proteins, including seven metabolic proteins, for
E. tarda
antioxidation and intracellular infection. Among them, two C4-dicarboxylate transporters were found necessary for
E. tarda
to disseminate in fish tissues. Furthermore, the substrate of the two transporters was identified as L-aspartate, which was proven to be essential for the full antioxidative capacity of
E. tarda
. Our results indicate that reprogramming the metabolic flux to the production of pyruvate, a ketoacid capable of neutralizing ROS, was likely a pivotal strategy of
E. tarda
to survive the oxidative environments inside host cells. Together, the findings of this study highlight the significance of metabolic reprogramming for bacterial redox homeostasis and intracellular infection.
Importance
Edwardsiella tarda
is a significant fish pathogen that can live in challenging environments of reactive oxygen species (ROS), such as inside the phagocytes. Metabolic reconfiguration has been increasingly associated with bacterial oxidative tolerance and virulence. However, the metabolic proteins of
E. tarda
involved in such processes remain elusive. By proteomic analysis and functional characterization of protein null mutants, the present study identified eight crucial proteins for bacterial oxidative resistance and intracellular infection. Seven of them are metabolic proteins dictating the metabolic flux toward the generation of pyruvate, a key metabolite capable of scavenging ROS molecules. Furthermore, L-aspartate uptake, which can fuel the pyruvate generation, was found essential for the full antioxidative capacity of
E. tarda
. These findings identified seven metabolic proteins involved in bacterial oxidative adaptation and indicate that metabolic reprogramming toward pyruvate was likely a pivotal strategy of bacteria for antioxidative adaptation and intracellular survival.
Publisher
American Society for Microbiology
Subject
Computer Science Applications,Genetics,Molecular Biology,Modeling and Simulation,Ecology, Evolution, Behavior and Systematics,Biochemistry,Physiology,Microbiology