Non-reducing polyketide synthase; part of the gene cluster that mediates the biosynthesis of an emodin derivative that may be involved in black Sigatoka disease of banana (PubMed:27513322, PubMed:27388157, PubMed:30735556). The pathway begins with the synthesis of atrochrysone thioester by the polyketide synthase PKS8-1 (Probable). The atrochrysone carboxyl ACP thioesterase MYCFIDRAFT_190111 then breaks the thioester bond and releases the atrochrysone carboxylic acid from PKS8-1 (Probable). The decarboxylase MYCFIDRAFT_34057 then catalyzes the concerted decarboxylation-elimination required to convert atochrysone carboxylic acid into emodin anthrone, which is further oxidized to emodin by the anthrone oxygenase MYCFIDRAFT_34418 (Probable). The functions of the other tailoring enzymes as well as the final product of the cluster have still to be identified (Probable). 8 H(+) + holo-[ACP] + 8 malonyl-CoA = atrochrysone carboxyl-[ACP] + 8 CO2 + 8 CoA + 2 H2O Secondary metabolite biosynthesis. Expression is positively regulated by the cluster-specific transcription factor MYCFIDRAFT_198930 and is up-regulated as early as 2 weeks post-inoculation and remains high through 9 weeks. 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.