Unraveling the complex regulatory network of DHN melanin biosynthesis and biological functions in phytopathogenic fungi

Abstract DHN (1,8-dihydroxynaphthalene) melanin is a significant secondary metabolite found in phytopathogenic fungi, predominantly localized in mature aerial hyphae, conidia, and appressoria. It performs various biological functions, including responding to extreme environments and regulating growth, development, and pathogenicity. Key biosynthetic enzymes and transcription factors directly involved in the DHN melanin synthesis pathway include melanin synthesis transcription factors, polyketide synthase, 1,3,6,8-tetrahydroxynaphthalene reductase, scytalone dehydratase, 1,3,8-trihydroxynaphthalene reductase, and a-hydrolase. The regulatory network controlling the DHN melanin biosynthesis is complex and multifaceted, involving various transcription factors, signaling pathways, and metabolic routes. This review provides a comprehensive summary of current research on the abundant biological functions of DHN melanin. Understanding the molecular mechanisms of DHN melanin synthesis in phytopathogenic fungi could facilitate the development of effective disease control strategies and novel therapeutic targets.