18 Velvet Regulation of Fungal Development

The velvet gene, or veA, is a fungal global regulator that has been shown to control diverse cellular processes, including asexual and sexual development. This regulator is conserved in numerous fungal species. Our knowledge of the velvet regulatory system has greatly expanded through studies of the model fungus Aspergillus nidulans, providing insight into its roles, such as control of morphogenesis, as well as its mechanism of action. Furthermore, over the last decade, the velvet regulator has been a research focus of numerous groups within the fungal scientific community, leading to experimental characterization of other velvet homologs in other Aspergillus species and in fungi of other genera. Research efforts have led to the discovery of other fungal proteins presenting a conserved velvet domain, similar to that originally identified in the veA gene product, VeA. These proteins form dimers, heterodimers, and heterotrimeric complexes with other proteins also involved in the regulation of morphogenesis, as well as metabolism and other cellular functions, in response to environmental stimuli, such as light or carbon source. This review focuses mainly on the current knowledge of the velvet regulatory system and its function in development and briefly describes other velvet-dependent roles in fungal species. The increasing advances in the elucidation of the mechanism of action of velvet proteins and interacting partners could facilitate the enhancement of beneficial aspects of fungi while decreasing detrimental impacts.