1,8-Dihydroxynaphthalene Melanin Biosynthesis in Colletotrichum fructicola Is Developmentally Regulated and Requires the Cooperative Function of Two Putative Zinc Finger Transcription Factors.

In ascomycetes, 1,8-dihydroxynaphthalene (DHN) melanin plays important protective functions and its production is usually coupled with development and environmental stress responses. The regulation of melanin biosynthesis, however, remains obscure. is a phytopathogen with a broad host range that produces melanized appressoria and perithecia. In this study, we annotated melanin genes in a high-quality genome and characterized two zinc finger transcription factors (TFs) ( and ) that form a loosely organized gene cluster with several melanin biosynthesis genes. Deleting either TF abolished melanization in both mycelia and perithecia but did not affect appressoria. The deletion mutants also showed perithecial development defects. Overexpressing in Δ strongly activated the expression of melanin biosynthesis genes including , , , and and caused hyper-accumulation of charcoal to black pigment(s). On the other hand, overexpressing in Δ activated , , and , but not . We conclude that proper DHN melanin accumulation in requires the cooperative function of two in-cluster TFs that also regulate perithecial development. The study clarifies DHN melanin regulations in and expands the function of melanin in-cluster TFs to sex regulation.