Quantitative proteomics provides insight into the response of the marine dinoflagellate Prorocentrum donghaiense to changes in ambient phosphorus

Dinoflagellates are the major causative agents of harmful algal blooms in the global ocean and they usually form blooms under conditions of very low dissolved inorganic phosphorus (DIP). However, the mechanisms underpinning the dinoflagellate blooms remain unclear. Here, we quantitatively compared protein expression profiles of a marine dinoflagellate, Prorocentrum donghaiense, grown in inorganic P-replete, P-deficient, and DIP- and dissolved organic phosphorus (DOP)-resupplied conditions by employing a Tandem Mass Tag (TMT)-based quantitative proteomic approach. Proteins involved in intracellular P reallocation, organic P, and non-P lipid utilization were up-regulated under the P-deficient condition, while inorganic phosphate transporters varied insignificantly. In response to the P resupplementation, nitrogen metabolism, ribosome, porphyrin, and chlorophyll metabolism were up-regulated, while lysosome, and starch and sucrose metabolism were down-regulated. Notably, photosynthesis was up-regulated and secondary metabolism was down-regulated only in the DIP-resupplied cells, whereas amino acid metabolism and vitamin B6 metabolism were up-regulated in the DOP-resupplied cells, indicating differential response mechanisms of P. donghaiense to DIP or DOP resupplementation. Our results indicated that P. donghaiense initiated multiple strategies in response to an ambient inorganic P-deficiency, and its efficient DOP assimilation by providing both P and carbon sources might be a key factor driving bloom formations of P. donghaiense in a low DIP environment.