TY - JOUR
T1 - Conserved cobalamin acquisition protein 1 is essential for vitamin B12 uptake in both Chlamydomonas and Phaeodactylum
AU - Sayer, Andrew P.
AU - Llavero-Pasquina, Marcel
AU - Geisler, Katrin
AU - Holzer, Andre
AU - Bunbury, Freddy
AU - Mendoza-Ochoa, Gonzalo I.
AU - Lawrence, Andrew D.
AU - Warren, Martin J.
AU - Mehrshahi, Payam
AU - Smith, Alison G.
N1 - Funding Information: This work was supported by the Biotechnology and Biological Sciences Research Council of the UK (BBSRC) Doctoral Training Partnership, grant no. BB/M011194/1 to A.P.S., M.L.P., and A.G.S.; grant no. BB/M018180/1 to P.M. and A.G.S.; grant no. BB/L002957/1 and BB/R021694/1 to K.G. and A.G.S.; grant no. BB/L014130/1 to G.I.M, K.G., P.M., and A.G.S.; grant no. BB/S002197/1 to M.J.W.; University of Cambridge Broodbank Fellowship to G.I.M; Royal Society grant no. INF\R2\180062 to M.J.W.; and Bill and Melinda Gates Foundation grant OPP1144 and Gates Cambridge Trust (Graduate Student Fellowship) to A.H.
PY - 2024/2
Y1 - 2024/2
N2 - Microalgae play an essential role in global net primary productivity and global biogeochemical cycling. Despite their phototrophic lifestyle, over half of algal species depend for growth on acquiring an external supply of the corrinoid vitamin B12 (cobalamin), a micronutrient produced only by a subset of prokaryotic organisms. Previous studies have identified protein components involved in vitamin B12 uptake in bacterial species and humans. However, little is known about its uptake in algae. Here, we demonstrate the essential role of a protein, cobalamin acquisition protein 1 (CBA1), in B12 uptake in Phaeodactylum tricornutum using CRISPR-Cas9 to generate targeted knockouts and in Chlamydomonas reinhardtii by insertional mutagenesis. In both cases, CBA1 knockout lines could not take up exogenous vitamin B12. Complementation of the C. reinhardtii mutants with the wild-type CBA1 gene restored B12 uptake, and regulation of CBA1 expression via a riboswitch element enabled control of the phenotype. When visualized by confocal microscopy, a YFP-fusion with C. reinhardtii CBA1 showed association with membranes. Bioinformatics analysis found that CBA1-like sequences are present in all major eukaryotic phyla. In algal taxa, the majority that encoded CBA1 also had genes for B12-dependent enzymes, suggesting CBA1 plays a conserved role. Our results thus provide insight into the molecular basis of algal B12 acquisition, a process that likely underpins many interactions in aquatic microbial communities.
AB - Microalgae play an essential role in global net primary productivity and global biogeochemical cycling. Despite their phototrophic lifestyle, over half of algal species depend for growth on acquiring an external supply of the corrinoid vitamin B12 (cobalamin), a micronutrient produced only by a subset of prokaryotic organisms. Previous studies have identified protein components involved in vitamin B12 uptake in bacterial species and humans. However, little is known about its uptake in algae. Here, we demonstrate the essential role of a protein, cobalamin acquisition protein 1 (CBA1), in B12 uptake in Phaeodactylum tricornutum using CRISPR-Cas9 to generate targeted knockouts and in Chlamydomonas reinhardtii by insertional mutagenesis. In both cases, CBA1 knockout lines could not take up exogenous vitamin B12. Complementation of the C. reinhardtii mutants with the wild-type CBA1 gene restored B12 uptake, and regulation of CBA1 expression via a riboswitch element enabled control of the phenotype. When visualized by confocal microscopy, a YFP-fusion with C. reinhardtii CBA1 showed association with membranes. Bioinformatics analysis found that CBA1-like sequences are present in all major eukaryotic phyla. In algal taxa, the majority that encoded CBA1 also had genes for B12-dependent enzymes, suggesting CBA1 plays a conserved role. Our results thus provide insight into the molecular basis of algal B12 acquisition, a process that likely underpins many interactions in aquatic microbial communities.
UR - http://www.scopus.com/inward/record.url?scp=85184595184&partnerID=8YFLogxK
U2 - 10.1093/plphys/kiad564
DO - 10.1093/plphys/kiad564
M3 - Article
AN - SCOPUS:85184595184
VL - 194
SP - 698
EP - 714
JO - Plant Physiology
JF - Plant Physiology
SN - 0032-0889
IS - 2
ER -