In this study, we report the discovery and molecular characterization of a novel mycovirus, Nigrospora oryzae fusarivirus 1 (NoFV1) isolated from the rice-infecting fungus Nigrospora oryzae. Excluding a poly (A) tail, the genome of the virus is 7004 nucleotide (nt) long containing three putative nonoverlapping open reading frames (ORF1, ORF2, and ORF3). The large ORF1 encodes a polypeptide with a conserved RNA-dependent RNA polymerase (RdRp) domain and a helicase domain that functions for RNA replication. Each of the smaller ORF2 and the smallest ORF3 encodes a putative protein with an unknown...