| Title | Biosynthesis and uptake of glycine betaine as cold-stress response to low temperature in fish pathogen Vibrio anguillarum |
|---|---|
| Author | Yue Ma1,2, Qiyao Wang1,2,3, Xiating Gao1, and Yuanxing Zhang1,2,3* |
| Address | 1State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, P. R. China, 2Shanghai Engineering Research Center of Maricultured Animal Vaccines, Shanghai 200237, P. R. China, 3Shanghai Collaborative Innovation Center for Biomanufacturing, Shanghai 200237, P. R. China |
| Bibliography | Journal of Microbiology, 55(1),44-55, 2017, |
| DOI | 10.1007/s12275-017-6370-2 |
| Key Words | compatible solute, glycine betaine, protectant, coldstress, Vibrio anguillarum |
| Abstract | Fish pathogen Vibrio anguillarum, a mesophile bacterium, is usually found in estuarine and marine coastal ecosystems worldwide that pose a constant stress to local organism by its fluctuation in salinity as well as notable temperature change. Though V. anguillarum is able to proliferate while maintain its pathogenicity under low temperature (5–18°C), so far, coldadaption molecular mechanism of the bacteria is unknown. In this study, V. anguillarum was found possessing a putative glycine betaine synthesis system, which is encoded by betABI and synthesizes glycine betaine from its precursor choline. Furthermore, significant up-regulation of the bet gene at the transcriptional level was noted in log phase in response to cold-stress. Moreover, the accumulation of betaine glycine was only found appearing at low growth temperatures, suggesting that response regulation of both synthesis system and transporter system are cold-dependent. Furthermore, in-frame deletion mutation in the two putative ABC transporters and three putative BCCT family transporters associated with glycine betaine uptake could not block cellular accumulation of betaine glycine in V. anguillarum under coldstress, suggesting the redundant feature in V. anguillarum betaine transporter system. These findings confirmed that glycine betaine serves as an effective cold stress protectant and highlighted an underappreciated facet of the acclimatization of V. anguillarum to cold environments. |