Identification of RNA-Associating Viruses with Yellow Cucurbits in South Eastern Iran and Genetic Diversity of the Prevalent Virus

Yellowing disease of greenhouse and open-grown cucurbits by whitefly-transmitted viruses is dramatically rising in the world and Iran. To study the viral infection of cucurbits in Sistan-Baluchistan Province, 195 leaf samples with viral symptoms were collected and tested for infection of some prevalent cucurbit viruses by RT-PCR using specific primers and some expected amplified DNA fragments were sequenced. Results confirmed the presence of viral infection (%59) in all surveyed areas. Including CABYV, CYSDV, CCYV, CVYV and WmCSV. The most infection of collected samples were %43, % 28 and % 8 of WmCSV, CVYV and CYSDV respectively. Phylogenetic analysis showed that the CYSDV isolates were divided into two sub-groups of East and West and two SB and SB2 isolates with 12 Iranian isolates and 4 Saudi Arabia isolates were clustered in eastern subgroup. Also genetic studies on the part of the coat protein gene showed that in Iranian isolates and Eastern subgroup the CGA had changed to CCA which led to the substitution of Glutamine by arginine at the codon position 73 of coat protein. Therefore, the nucleotide differences of Iranian isolates than the isolates from different regions indicate high genetic diversity and long dating of this native virus in Iran.