Guanine, a high-capacity and rapid-turnover nitrogen reserve in microalgal cells
Peter Mojzeš, Lu Gao, T. T. Ismagulova, Jana Pilátová, Šárka Moudříková, Olga Gorelova, Alexei Solovchenko, Ladislav Nedbal, Anya Salih
Abstract
Significance Vast areas of the oceans are N limited, and how microalgae can flourish in these N-poor waters is still not known. Furthermore, mechanisms and sites of N uptake and storage have not been fully determined. We show that crystalline guanine (C 5 H 5 N 5 O) is an important N storage form for phytoplankton and for symbiotic dinoflagellates of corals. The widespread occurrence of guanine reserves among taxonomically distant microalgal species suggests an early evolutionary origin of its function as N storage. Crystalline guanine appears to be a multifunctional biochemical with an important role in the N cycle that remains to be elucidated. In particular, a better knowledge of N-storage metabolism is necessary to understand the impact of eutrophication on coral-symbiont interaction.