Authors: Yanchun You, Xueqiong Sun, Minglei Ma, Jiamin He, Ling Li, Felipe Wendt Porto, Senjie Lin
Published: 2022-07-12
DOI: 10.1038/s41467-022-31802-6
Source: Full article
AbstractTrypsin is best known as a digestive enzyme in animals, but remains unexplored in phytoplankton, the major primary producers in the ocean. Here we report the prevalence of trypsin genes in global ocean phytoplankton and significant influences of environmental nitrogen (N) and phosphorus (P) on their expression. UsingCRISPR/Cas9mediated-knockout and overexpression analyses, we further reveal that a trypsin inPhaeodactylum tricornutum(PtTryp2) functions to repress N acquisition, but its expression decreases under N-deficiency to promote N acquisition. On the contrary,PtTryp2promotes phosphate uptake per se, and its expression increases under P-deficiency to further reinforce P acquisition. Furthermore,PtTryp2knockout led to amplitude magnification of the nitrate and phosphate uptake ‘seesaw’, whereasPtTryp2overexpression dampened it, linkingPtTryp2to stabilizing N:P stoichiometry. Our data demonstrate thatPtTryp2is a coordinate regulator of N:P stoichiometric homeostasis. The study opens a window for deciphering how phytoplankton adapt to nutrient-variable marine environments.