Reducing polyketide synthase; part of the gene cluster that mediates the biosynthesis of fusaric acid, a mycotoxin with low to moderate toxicity to animals and humans, but with high phytotoxic properties (PubMed:25372119). L-aspartate is suggested as fusaric acid amino acid precursor that is activated and further processed to O-acetyl-L-homoserine by cluster enzymes aspartate kinase FUB3 and homoserine O-acetyltransferase FUB5, as well as enzymes of the primary metabolism (By similarity). The polyketide synthase (PKS) FUB1 generates the triketide trans-2-hexenal which is presumptively released by the hydrolase FUB4 and linked to the NRPS-bound amino acid precursor by NAD(P)-dependent dehydrogenase FUB6 (By similarity). FUB1, FUB4, and the non-canonical NRPS Fub8 may form an enzyme complex (By similarity). Further processing of the NRPS-bound intermediate might be carried out by FUB6 and the sulfhydrylase FUB7, enabling a spontaneous electrocyclization to close the carbon backbone of fusaric acid (By similarity). Dihydrofusaric acid is likely to be released via reduction by the thioester reductase (TR) domain of FUB8 whereupon the final oxidation to fusaric acid may (also) be performed by the FMN-dependent dehydrogenase FUB9 (By similarity). Mycotoxin 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. Reduces to 5% the production of fusaric acid (PubMed:25372119). Fusaric acid is phytotoxic to plants such as cotton and banana (PubMed:20955724, PubMed:23922960). It has been shown to induce programmed cell death in plants (PubMed:16868776, PubMed:23838885). In addition to a mild toxicity to animals, fusaric acid exhibits acanthamoebicidal, antioomycete, and antimycobacterial activities (PubMed:17927749, PubMed:22864988, PubMed:21811925).