Domoic acid biosynthesis in the red alga Chondria armata suggests a complex evolutionary history for toxin production

Significance Originally isolated from the red algaChondria armata , domoic acid (DA) is best known as a potent marine neurotoxin produced by oceanic harmful algal blooms of planktonic diatoms. Sequencing efforts to date of kainoid-producing red algae have focused exclusively on a closely related molecule, kainic acid, leaving a gap in the understanding of DA biosynthesis in red algae and its evolutionary linkage to diatoms. Here, we present the phylogenetic and biochemical investigation of DA biosynthesis inC. armata . This work demonstrates the high synteny of DA biosynthetic genes between relatively distant taxonomic groups of algae and suggests a complex evolutionary history for DA biosynthesis involving gene transfer and neofunctionalization.