Polyketide synthase; part of the gene cluster 41 that mediates the biosynthesis of an extracellular and diffusible metabolite that is able to stimulate colony sclerotial production (PubMed:27647242). Expression is positively regulated by developmental regulators veA and velB but not by the global regulator of secondary metabolism laeA (PubMed:27647242). Reduces the production of sclerotia (PubMed:27647242).