title: Cucumis melo endornavirus: Genome organization, host range and co-divergence with the host.
abstract: A high molecular weight dsRNA was isolated from a Cucumis melo L. plant (referred to as 'CL01') of an unknown cultivar and completely sequenced. Sequence analyses showed that dsRNA is associated with an endornavirus for which a name Cucumis melo endornavirus (CmEV) is proposed. The genome of CmEV-CL01 consists of 15,078 nt, contains a single, 4939 codons-long ORF and terminates with a stretch of 10 cytosine residues. Comparisons of the putative CmEV-encoded polyprotein with available references in protein databases revealed a unique genome organization characterized by the presence of the following domains: viral helicase Superfamily 1 (Hel-1), three glucosyltransferases (doublet of putative capsular polysaccharide synthesis proteins and a putative C_28_Glycosyltransferase), and an RNA-dependent RNA polymerase (RdRp). The presence of three glycome-related domains of different origin makes the genome organization of CmEV unique among endornaviruses. Phylogenetic analyses of viral RdRp domains showed that CmEV belongs to a specific lineage within the family Endornaviridae made exclusively of plant-infecting endornaviruses. An RT-PCR based survey demonstrated high incidence of CmEV among melon germplasm accession (>87% of tested samples). Analyses of partial genome sequences of CmEV isolates from 26 different melon genotypes suggest fine-tuned virus adaptation and co-divergence with the host. Finally, results of the present study revealed that CmEV is present in plants belonging to three different genera in the family Cucurbitaceae. Such diverse host range is unreported for known endornaviruses and suggests a long history of CmEV association with cucurbits predating their speciation.
authors.affiliation: Department of Biochemistry, Molecular Biology, Entomology and Plant Pathology, Mississippi State University, Mississippi State, MS 39762, USA. Electronic address: ss501@msstate.edu.
authors.forename: Sead
authors.initials: S
authors.lastname: Sabanadzovic
authors.affiliation: United States Department of Agriculture-Agricultural Research Service, Salinas, CA 93905, USA.
authors.forename: William M
authors.initials: WM
authors.lastname: Wintermantel
authors.affiliation: Department of Plant Pathology and Crop Physiology, Louisiana State University Agricultural Center, Baton Rouge, LA 70803, USA.
authors.forename: Rodrigo A
authors.initials: RA
authors.lastname: Valverde
authors.affiliation: United States Department of Agriculture-Agricultural Research Service, Salinas, CA 93905, USA.
authors.forename: James D
authors.initials: JD
authors.lastname: McCreight
authors.affiliation: Institute for Genomics, Biocomputing and Biotechnology, Mississippi State, MS 39762, USA.
authors.forename: Nina
authors.initials: N
authors.lastname: Aboughanem-Sabanadzovic
mesh_terms: D000595:Amino Acid Sequence; D028463:Cucumis melo / Q000821:virology*; D004279:DNA, Viral; D023061:Gene Order; D016679:Genome, Viral; D005838:Genotype; D054884:Host-Pathogen Interactions; D008969:Molecular Sequence Data; D010802:Phylogeny; D010942:Plant Viruses / Q000145:classification / Q000502:physiology*; D012328:RNA Viruses / Q000145:classification / Q000502:physiology*; D012367:RNA, Viral; D016415:Sequence Alignment; D014764:Viral Proteins / Q000737:chemistry / Q000235:genetics; D056189:Viral Tropism
chemical_list: D004279:DNA, Viral; D012367:RNA, Viral; D014764:Viral Proteins
keywords: Endornavirus; Evolution; Genome; Melon; Phylogenetics