Non-reducing polyketide synthase; part of the gene cluster that mediates the biosynthesis of anditomin, a fungal meroterpenoid (PubMed:25216349). The first step of the pathway is the synthesis of 3,5-dimethylorsellinic acid (DMOA) by the polyketide synthase andM (PubMed:25216349). DMOA is then converted to the phthalide compound 5,7-dihydroxy-4,6-dimethylphthalide (DHDMP) by the cytochrome P450 monooxygenase andK, which is further prenylated by the prenyltransferase andD to yield farnesyl-DHDMP (PubMed:25216349). Further epoxidation by the FAD-dependent monooxygenase andE leads to epoxyfarnesyl-DHDMP (PubMed:25216349). The next step involves the terpene cyclase andB that converts epoxyfarnesyl-DHDMP into preandiloid A through opening of the epoxide ring followed by the cyclization of the farnesyl moiety (PubMed:25216349). Preandiloid A is in turn oxidized at the C-3 hydroxyl group to yield preandiloid B by the dehydrogenase andC (PubMed:25216349). The dioxygenase andA is solely responsible for the dehydrogenation of preandiloid B leading to the enone preandiloid C, as well as for the intriguing structural rearrangement to generate the bicyclo[2.2.2]octane core, transforming preandiloid C into andiconin (PubMed:25216349). FAD-binding monooxygenase andJ then produces andilesin D which is reduced by dehydrogenase andI to yield andilesin A (PubMed:25216349). Action of acetyltransferase andG followed by a spontaneous acetate elimination leads then to andilesin B, which is in turn substrate of the short chain dehydrogenase andH to yield andilesin C (PubMed:25216349). Finally, the dioxygenase andF catalyzes the transformation of andilesin C to anditomin (PubMed:25216349). acetyl-CoA + 3 malonyl-CoA + 2 S-adenosyl-L-methionine = 3,5-dimethylorsellinate + 3 CO2 + 4 CoA + 2 S-adenosyl-L-homocysteine Secondary metabolite biosynthesis; terpenoid biosynthesis. Multidomain protein; including a starter unit:ACP transacylase (SAT) that selects the starter unit; a ketosynthase (KS) that catalyzes repeated decarboxylative condensation to elongate the polyketide backbone; a malonyl-CoA:ACP transacylase (MAT) that selects and transfers the extender unit malonyl-CoA; a product template (PT) domain that controls the immediate cyclization regioselectivity of the reactive polyketide backbone; and an acyl-carrier protein (ACP) that serves as the tether of the growing and completed polyketide via its phosphopantetheinyl arm (PubMed:25216349). The release of the polyketide chain from the non-reducing polyketide synthase is mediated by the thioesterase (TE) domain localized at the C-ter of the protein (By similarity).