Journal of experimental botany | 2021
Organophosphorus hydrolysis by diatom purple acid phosphatase and sequential regulation of cell metabolism.
Abstract
Phosphorus (P) limitation affects the phytoplankton growth and population in aquatic systems, consequently limits aquatic primary productivity. To cope with P limitation, plants have evolved a range of metabolic responses such as accumulation of purple acid phosphatases (PAP) to enhance phosphates acquisition. However, it remains unknown whether algae adopt a similar mechanism. Here we exemplified the role of PAPs in the model microalga Phaeodactylum tricornutum. PAP1 expression was enhanced in P. tricornutum cells grown on organophosphorus compared to inorganic phosphate. PAP1 overexpression ameliorated cellular growth and biochemical composition in a growth-phase dependent manner. PAP1 promoted growth and photosynthesis during growth phases and reallocated carbon flux towards lipogenesis in the stationary phase. PAP1 was ER localized and orchestrated the expression of genes involved in key metabolic pathways and Pi translocation, thereby ameliorated energy, reducing equivalents and antioxidant potential. PAP1 silencing induced its homolog PAP2 expression, thereby replenished Pi scavenging activity of PAP1. Our investigation unravels the PAP1 associated metabolic regulations in a sequential manner, providing a novel insight in algal phosphorus metabolism and aquatic primary productivity.