Cytochrome P450 monooxygenase; part of the gene cluster that mediates the biosynthesis of the trisnorsesquiterpene discodiene which has a function during later stages of multicellular development, during the transition from fingers to Mexican hats (PubMed:31063135). The terpene synthase tps8 converts its substrate farnesyl diphosphate (FDP) into the bicyclic sesquiterpene alcohol discoidol (PubMed:31063135). The cytochrome P450 monooxygenase cyp521A1 then catalyzes the oxidative degradation of discoidol to form the trisnorsesquiterpene discodiene (PubMed:31063135). Sesquiterpene biosynthesis. Expression is almost undetectable in vegetatively growing cells (PubMed:31063135). Small amounts of transcripts accumulate between 4-8 hrs of development, continue to accumulate until they peak at 16 hrs, and decline thereafter (PubMed:31063135). Belongs to the cytochrome P450 family.