Phosphorus (P) is an essential nutrient for marine phytoplankton as for other living organisms, and the preferred form, dissolved inorganic phosphate (DIP), is often quickly depleted in the sunlit layer of the ocean. Phytoplankton have developed mechanisms to utilize organic forms of P (DOP). Hydrolysis of DOP to release DIP by alkaline phosphatase is believed to be the most common mechanism of DOP utilization. Little effort has been made, however, to understand other potential molecular mechanisms of utilizing different types of DOP. This study investigated the bioavailability of glucose-6-phosphate (G6P) and its underlying molecular mechanism in the dinoflagellate Karenia mikimotoi. Suppression Subtraction Hybridization (SSH) was used to identify genes up- and down-regulated during G6P utilization compared to DIP condition. The results showed that G6P supported the growth and yield of K. mikimotoi as efficiently as DIP. Neither DIP release nor AP activity was detected in the cultures grown in G6P medium, however, suggesting direct uptake of G6P. SSH analysis and RT-qPCR results showed evidence of metabolic modifications, particularly that mitochondrial ATP synthase f1 gamma subunit and thioredoxin reductase were up-regulated while diphosphatase and pyrophosphatase were down-regulated in the G6P cultures. All the results indicate that K. mikimotoi has developed a mechanism other than alkaline phosphatase to utilize G6P.

磷（P）和其他生物一样，是海洋浮游植物的必需养分，而溶解的无机磷酸盐（DIP）的首选形式通常会在阳光充足的海洋中迅速耗尽。浮游植物已开发出利用有机磷（DOP）的机制。碱性磷酸酶水解DOP以释放DIP被认为是DOP利用的最常见机制。然而，几乎没有任何努力来了解利用不同类型DOP的其他潜在分子机制。这项研究调查了6-鞭毛藻（Karinonia mikimotoi）中6-磷酸葡萄糖（G6P）的生物利用度及其潜在的分子机制。。与DIP条件相比，抑制消减杂交（SSH）用于鉴定在G6P利用过程中上调和下调的基因。结果表明，G6P与DIP一样有效地支持了mikimotoi的生长和产量。然而，在G6P培养基中生长的培养物中未检测到DIP释放或AP活性，表明直接摄取G6P。SSH分析和RT-qPCR结果显示了代谢修饰的证据，特别是G6P培养物中上线粒体ATP合酶f1γ亚基和硫氧还蛋白还原酶上调，而二磷酸酶和焦磷酸酶下调。所有结果表明，三本K.Ki已经开发出一种除碱性磷酸酶以外的机制来利用G6P。