Mobilization and Cellular Distribution of Phosphate in the Diatom .

Unicellular organisms that live in marine environments must cope with considerable fluctuations in the availability of inorganic phosphate (P). Here, we investigated the extracellular P concentration-dependent expression, as well as the intracellular or extracellular localization, of phosphatases and phosphate transporters of the diatom . We identified P-regulated plasma membrane-localized, ER-localized, and secreted phosphatases, in addition to plasma membrane-localized, vacuolar membrane-localized, and plastid-surrounding membrane-localized phosphate transporters that were also regulated in a P concentration-dependent manner. These studies not only add further knowledge to already existing transcriptomic data, but also highlight the capacity of the diatom to distribute P intracellularly and to mobilize P from extracellular and intracellular resources.