Mehrshad, Maliheh
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences
Abstract
Vitamin B12 (B12) is an essential cofactor for vital metabolic processes in both prokaryotes and eukaryotes. De novo B(12 )biosynthesis is exclusively carried out by a modicum of prokaryotes, although being required by most organisms. Recently, it has been demonstrated that not all B-12-prototrophic bacteria voluntarily share this vital cofactor and, therefore, are termed B-12-retainers. Consequently, low biosynthesis potential and limited voluntary release lead to a large discrepancy between availability and demand for B-12 in the ocean, indicating that release of B12 may be an important control. Hence, in this study, we examined a specific release process, cell lysis after phage infection. We isolated bacteriophages specific for the B-12-prototrophic, yet B-12-retainer bacterium Sulfitobacter sp. M39. The addition of the bacteriophages to a Sulfitobacter sp. M39 mono-culture led to a significant increase in virus-like particles, reduced bacterial growth, and quantifiable extracellular dissolved B-12. When introducing bacteriophages to a co-culture comprising the host bacterium and the B-12-auxotrophic diatom Thalassiosira pseudonana, we observed rapid response in the form of microalgal growth. Our results indicate that B(12 )is released as a result of bacteriophage-mediated cell lysis of Sulfitobacter sp. M39, enabling the growth of T. pseudonana in co-culture and possibly other microbes in nature. Therefore, we propose that bacteriophage-mediated cell lysis is a key mechanism for the release of essential metabolites, including vitamins, and given the estimated bacteriophage infection rates in the ocean, it plays a crucial role in the B-vitamin cycle in the marine environment.
Keywords
vitamin B-12; cobalamin; bacteriophages; bacteriophage-mediated cell lysis; diatom; metabolite cross-feeding; marine microbial community; microbial interaction
Published in
ISME Communications
2025, volume: 5, number: 1, article number: ycaf136
Publisher: OXFORD UNIV PRESS
SLU Authors
UKÄ Subject classification
Microbiology
Ecology
Publication identifier
- DOI: https://doi.org/10.1093/ismeco/ycaf136
Permanent link to this page (URI)
https://res.slu.se/id/publ/143930