Extending phylogenetic coverage to assess the taxonomic potential of heterocyte glycolipids

Abstract

The cyanobacteria family Nostocales evolved the ability to fix N₂ under anoxic conditions by utilizing a group of specialized lipids (heterocyte glycolipids, HGs) to regulate gas flux into the cell interior. It was found that closely related species often yield similar HG signatures, suggesting potential for taxonomic profiling. Also, the ratio of specific HGs was found to correlate with lake water temperature, making HG ratios promising novel proxies for continental climate reconstructions. Compared to the total number of heterocytous cyanobacteria, only a limited number of species has been investigated for their HG inventory so far. We investigated 18 Nostocales strains collected from New Zealand using HPLC-MS² that are yet uncharacterized for their HG content. Our observations indicate a high potential of HGs for studying chemotaxonomic relationships between heterocytous cyanobacteria and reconstructing changes of past cyanobacterial communities