Variation in intracellular polyphosphate and associated gene expression in response to different phosphorus conditions in the dinoflagellate Karenia mikimotoi

•K. mikimotoi showed a strong capability to mobilize cellular P pool for growth under P deficiency.•PolyP only contributed approximately 1–3 % to particulate P in K. mikimotoi.•K. mikimotoi utilized P components other than polyP under P deficiency.•Cellular polyP was mobilized until severe P limitation.•PolyP may not play a crucial role in cellular P storage in dinoflagellates.