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). Required for gall induction and teliospore formation on seedlings (PubMed:24064149). Forms a heterodimeric complex with velB; the formation of the VEL2-VOS1 complex is light-dependent (By similarity). The N-terminal velvet domain contains a NF-kappa-B-like fold and is involved in DNA-binding (By similarity). Leads to reduced virulence (PubMed:24064149). Belongs to the velvet family. VosA subfamily.