Phylogenetic comparison of Coat Protein nucleotide and amino acid sequence of Cucumber green mottle mosaic virus from Khorasan province with other isolates of the world

Cucumber green mottle mosaic virus (CGMMV) infects many cucurbit species in the world and causing mottle and systemic mosaic symptoms on cucurbitaceous plant leaves. During a survey, Out of 198 samples of cucurbit plants that were collected from the different fields and cucumber greenhouses in khorasan province, 39 samples were infected by CGMMV in DAS-ELISA using specific polyclonal antibody (The rate of infection was 19.7%). Using specific primers which were designed based on the CGMMV coat protein (CP) gene sequence; a fragment with 486bp length was amplified by reverse transcription polymerase chain reaction (RT-PCR). The CP gene was cloned, sequenced and compared with the sequence of homologous gene of other CGMMV isolates recorded in GeneBank. Phylogenetic analysis using 486 nucleotide long sequences of coat protein gene showed that all CGMMV sequences can be placed into two groups: I and II. Members of group I were divided into two subgroups: A, B. Iranian isolate (kalat) was classified in the group IA. The result showed it had high homology with the other isolates (the highest homology could reach 97.9% in nucleic acid level). As well, phylogenetic tree based on CP amino acid sequences was established and the highest amino acid homology was 98.1%. This is the first report of CP sequence of CGMMV Iranian isolate, determination of its phylogenetic relationship and comparison of its nucleotide and amino acid sequences with those of the other isolates of CGMMV obtained from GenBank.