Non-reducing polyketide synthase; part of the gene cluster that mediates the biosynthesis of the bianthraquinone cladofulvin, a conidial pigment not required for virulence but that plays a role in fitness and resistance to environmental stresses including UV light and low-temperature stress (PubMed:24465762, PubMed:27274078, PubMed:27997759). The pathway begins with the synthesis of atrochrysone thioester by the polyketide synthase (PKS) claG. The atrochrysone carboxyl ACP thioesterase claF then breaks the thioester bond and releases the atrochrysone carboxylic acid from claG (PubMed:27274078). This compound is decarboxylated by claH to yield emodin, which is further converted to chrysophanol hydroquinone by the reductase claC and the dehydratase claB (PubMed:27274078). The cytochrome P450 monooxygenase claM then catalyzes the dimerization of nataloe-emodin to cladofulvin (PubMed:27274078). 8 H(+) + holo-[ACP] + 8 malonyl-CoA = atrochrysone carboxyl-[ACP] + 8 CO2 + 8 CoA + 2 H2O Pigment biosynthesis. Expression is positively regulated by the transcriptional regulator wor1 (PubMed:24521437, PubMed:27274078). Exhibits high expression at the early stages of infection when runner hyphae were growing on the tomato leaf surface (PubMed:24465762). Expression drops after penetration when the fungus is colonizing the apoplastic space between mesophyll cells (PubMed:24465762, PubMed:27997759). The expression is induced at later stages of infection when conidiophores emerge from the plant and produce conidia (PubMed:24465762). 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. Impairs the production of cladofulvin (PubMed:27274078). Does not affect virulence (PubMed:27997759).