Molecular characterization of a novel polymycovirus identified in the phytopathogenic fungus Colletotrichum gloeosporioides

Abstract

A novel polymycovirus isolating from plant-pathogenic fungus Colletotrichum gloeosporioides was identi ed. The virus were composed nine RNA segments, ranging from 699 bp to 2,444 bp, and except that RNA5 contains two open reading frames (ORF5-1 and ORF5-2), other RNA segement contain only one ORF. In addition,the proteins encoded by ORFs 1-8 were homologous to the protein encoded by ORFs 1-8 in Colletotrichum camelliae lamentous virus 1(CcFV-1) by BLASTp. The amino acid sequence between the RNA-dependent RNA polymerase (RdRp) encoded by ORF1 and the viral methyltransferase encoded by ORF3 shared 87.6% and 83.3% identity with CcFV-1. The proline-alanine-serine-rich protein (PASrp) encoded by ORF4 shows 86.6% sequence homology to that of CcFV-1. The sequence homology of proteins encoded by ORFs2, 5-1, 6, 7 and 8 with the corresponding proteins of CcFV-1 was 86.6%, 82.5%, 89.0%, 45.7% and 95.5%, respectively. However, RNA9 is a defective RNA of RNA2, missing the 1556 bp (nt 519 to nt 2074) intermediate fragment of RNA2. Phylogenetic analysis based on RdRp protein indicated that the virus, which is the phylogenetically closest relative of CcFV-1, clustered with members of the family Polymycoviridae, so we tentatively named it "Colletotrichum gloeosporioides polymycovirus virus 1" (CgPmV1). To our knowledge, this is the rst report of a defective polymycovirus in C. gloeosporioides.

A novel narnavirus isolated from Colletotrichum curcumae strain 780-2T

“…Colletotrichum curcumae is a lamentous fungus that causes the leaf blight disease of Curcuma wenyujin, which results in huge economic losses [14]. A number of mycoviruses or dsRNA elements have been identi ed in Colletotrichum, such as Colletotrichum gloeosporioides RNA virus 1 (CgRV1) of the family Partitiviridae [15], Colletotrichum gloeosporioides botourmiavirus 1 (CcBV1) of the family Botourmiaviridae [16], Colletotrichum gloeosporioides ourmia-like mycovirus (CgOLV1) of the family Ourmiaviridae, etc [17][18][19][20][21][22][23][24][25][26][27][28]. So far, Narnaviruses have not been reported in C. curcumae.…”