Global distribution of a chlorophyll f cyanobacterial marker

• Main Authors: Antonaru, Laura A., Cardona, Tanai, Larkum, Anthony W. D., Nürnberg, Dennis J.
• Format: Text
• Language: unknown
• Published: Freie Universität Berlin 2020
• Subjects: Environmental microbiology; Microbial ecology; 500 Naturwissenschaften und Mathematik530 Physik530 Physik; 500 Naturwissenschaften und Mathematik570 Biowissenschaften; Biologie577 Ökologie; Antarctic; Arctic; Antarc*
• Online Access: https://dx.doi.org/10.17169/refubium-29748; https://refubium.fu-berlin.de/handle/fub188/30006

Some cyanobacteria use light outside the visible spectrum for oxygenic photosynthesis. The far-red light (FRL) region is made accessible through a complex acclimation process that involves the formation of new phycobilisomes and photosystems containing chlorophyll f. Diverse cyanobacteria ranging from unicellular to branched-filamentous forms show this response. These organisms have been isolated from shaded environments such as microbial mats, soil, rock, and stromatolites. However, the full spread of chlorophyll f-containing species in nature is still unknown. Currently, discovering new chlorophyll f cyanobacteria involves lengthy incubation times under selective far-red light. We have used a marker gene to detect chlorophyll f organisms in environmental samples and metagenomic data. This marker, apcE2, encodes a phycobilisome linker associated with FRL-photosynthesis. By focusing on a far-red motif within the sequence, degenerate PCR and BLAST searches can effectively discriminate against the normal chlorophyll a-associated apcE. Even short recovered sequences carry enough information for phylogenetic placement. Markers of chlorophyll f photosynthesis were found in metagenomic datasets from diverse environments around the globe, including cyanobacterial symbionts, hypersaline lakes, corals, and the Arctic/Antarctic regions. This additional information enabled higher phylogenetic resolution supporting the hypothesis that vertical descent, as opposed to horizontal gene transfer, is largely responsible for this phenotype’s distribution.