Alkaline phosphatase gene sequence characteristics and transcriptional regulation by phosphate limitation in Karenia brevis (Dinophyceae)

摘要: The toxic dinoflagellate Karenia brevis Davis forms harmful algal blooms and has caused devastating consequences in the Gulf of Mexico past decades. While phosphorus nutrient is believed to play an important role bloom formation, molecular mechanism still poorly understood. In this study, we explored alkaline phosphatase (AP) K. brevis, enzyme known facilitate utilization dissolved organic (DOP) other phytoplankton when inorganic (DIP) limited environment. We isolated full-length cDNAs AP gene (kbrap) from species characterized its expression pattern under contrasting DIP conditions. Analysis deduced amino acid sequence revealed that a membrane-associated protein, consistent with predominant cell surface localization activity detected by labeled fluorescence labeling. Phylogenetic analyses indicate kbrap closest homolog another dinoflagellate, Amphidinium carterae, at both nucleotide levels. two APs share similarity key domains diatom APs, are phylogenetically more closely related counterparts diatoms than those green algae bacteria. When cells were cultured DIP-limited medium, increased markedly (5–6-fold higher initial values), following slight brief increase level, while concentrations cultures decreased significantly. transcription level repressed was resupplied cultures. Our results suggest enables grow DOP-rich environments, but mode response different A. carterae.