Responses of Chlamydomonas reinhardtii during the transition from P-deficient to P-sufficient growth (the P-overplus response): The roles of the vacuolar transport chaperones and polyphosphate synthesis.

Phosphorus (P) assimilation and polyphosphate (polyP) synthesis were investigated in Chlamydomonas reinhardtii by supplying phosphate (PO ; 10 mg P·L ) to P-depleted cultures of wildtypes, mutants with defects in genes involved in the vacuolar transporter chaperone (VTC) complex, and VTC-complemented strains. Wildtype C. reinhardtii assimilated PO and stored polyP within minutes of adding PO to cultures that were P-deprived, demonstrating that these cells were metabolically primed to assimilate and store PO .