Metabolic inhibitor induces dynamic changes in saxitoxin biosynthesis and metabolism in the dinoflagellate Alexandrium pacificum (Group IV) under in vivo labeling condition

•The first study that combine in vivo labelling and stress treatment on dinoflagellates.•De novo and salvage pathways show separate regulation of STX production.•Colchicine appears to decrease STX production via effects on nitrate assimilation.•De novo STX biosynthesis was enhanced after suppression by colchicine.•Colchicine had a lesser effect on the salvage pathway than on the de novo pathway.