Non-reducing polyketide synthase that condenses acetate units to form a heptaketide naphthopyrene YWA1, a yellow pigment found in mature asexual spores (conidia), via a polyketomethylene intermediate step. acetyl-CoA + 6 H(+) + 6 malonyl-CoA = 6 CO2 + 7 CoA + H2O + YWA1 Binds 2 phosphopantetheines covalently. Polyketide biosynthesis; heptaketide naphthopyrone YWA1 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 2 acyl-carrier protein (ACP) domains that serve as the tethers of the growing and completed polyketide via their phosphopantetheinyl arm. The C-terminal region is involved in Claisen-type cyclization of the second ring of naphthopyrone.