Component of the velB-VosA heterodimeric complex that plays a dual role in activating genes associated with spore maturation and repressing certain development-associated genes (By similarity). The complex binds DNA through the DNA-binding domain of vosA that recognizes an 11-nucleotide consensus sequence 5'-CTGGCCGCGGC-3' consisting of two motifs in the promoters of key developmental regulatory genes (By similarity). Regulates spore viability, trehalose accumulation, and tolerance to thermal and oxidative as well as ion stresses (PubMed:26399184). Positively regulates conidial pigmentation and pathogenicity on barley (PubMed:26399184). Forms a heterodimeric complex with VEL2; the formation of the VEL2-VOS1 complex is light-dependent (By similarity). Expression is up-regulated in conidia (PubMed:26399184). The N-terminal velvet domain contains a NF-kappa-B-like fold and is involved in DNA-binding (By similarity). Reduces the amount of thehalose in conidia, tolerance to heat, oxidative and osmotic stress (PubMed:26399184). Belongs to the velvet family. VosA subfamily.