Proteorhodopsin light-enhanced growth linked to vitamin-B1 acquisition in marine Flavobacteria.

Autor: Gómez-Consarnau L; Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA., González JM; Department of Microbiology, University of La Laguna, La Laguna, Spain., Riedel T; Department of Microbial Ecology and Diversity Research, Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany., Jaenicke S; Center for Biotechnology-CeBiTec, Bielefeld, Germany., Wagner-Döbler I; Research Group Microbial Communication, Helmholtz Centre for Infection Research, Braunschweig, Germany., Sañudo-Wilhelmy SA; Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA., Fuhrman JA; Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA.
Jazyk: angličtina
Zdroj: The ISME journal [ISME J] 2016 May; Vol. 10 (5), pp. 1102-12. Date of Electronic Publication: 2015 Nov 17.
DOI: 10.1038/ismej.2015.196
Abstrakt: Proteorhodopsins (PR) are light-driven proton pumps widely distributed in bacterioplankton. Although they have been thoroughly studied for more than a decade, it is still unclear how the proton motive force (pmf) generated by PR is used in most organisms. Notably, very few PR-containing bacteria show growth enhancement in the light. It has been suggested that the presence of specific functions within a genome may define the different PR-driven light responses. Thus, comparing closely related organisms that respond differently to light is an ideal setup to identify the mechanisms involved in PR light-enhanced growth. Here, we analyzed the transcriptomes of three PR-harboring Flavobacteria strains of the genus Dokdonia: Dokdonia donghaensis DSW-1(T), Dokdonia MED134 and Dokdonia PRO95, grown in identical seawater medium in light and darkness. Although only DSW-1(T) and MED134 showed light-enhanced growth, all strains expressed their PR genes at least 10 times more in the light compared with dark. According to their genomes, DSW-1(T) and MED134 are vitamin-B1 auxotrophs, and their vitamin-B1 TonB-dependent transporters (TBDT), accounted for 10-18% of all pmf-dependent transcripts. In contrast, the expression of vitamin-B1 TBDT was 10 times lower in the prototroph PRO95, whereas its vitamin-B1 synthesis genes were among the highest expressed. Our data suggest that light-enhanced growth in DSW-1(T) and MED134 derives from the use of PR-generated pmf to power the uptake of vitamin-B1, essential for central carbon metabolism, including the TCA cycle. Other pmf-generating mechanisms available in darkness are probably insufficient to power transport of enough vitamin-B1 to support maximum growth of these organisms.
Databáze: MEDLINE