Genetic analyses ofCochliobolus heterostrophus albino mutant with deficiencies at two loci

A new class of albino mutant ofCochliobolus heterostrophus was isolated. Its colony color was indistinguishable from that of albino mutants previously reported. Application of the melanin intermediate scytalone induced this mutant to pigment slightly, but not completely. Genetic analyses showed that the mutant had two deficient genes. When only one of these genes was deficient, the colony color was indistinguishable from the wild type, whereas deficiency of both genes resulted in the albino phenotype. These deficiencies lie upstream of scytalone biosynthesis. These genes were designated asCal1 andCal2.