Molecular detection of Cucumber vein yellowing virus and Cucurbit yellow stunting disorder virus in southeastern Iran and the genetic analysis of isolates from CVYV

Yellowing diseases of field and greenhouse-grown cucurbits caused by whitefly-transmitted viruses are increasingly becoming important and cause economic losses in many cucurbits growing areas of the world. In this research, 195 samples with symptoms yellowing, stunting and deformation of leaves were collected from fields of cucurbits in the South-East Iran (Sistan and Baluchestan). In order to detect CVYV and CYSDV, cDNAs were prepared using Random Hexamer primer and total RNAs extracted from the collected samples.Then, Polymerase Chain Reaction (PCR) was performed using exteracted RNA and specific primers (CYSCPf and CYSCPr for CYSDV, CV+ and CV- for CVYV). The results revealed that a 450 bp fragment from the CVYV-CP and a 700 bp fragment from CYSDV-CP were amplified from 55 and 17 samples, respectively. About 7% of the samples had simultaneous contamination with the two viruses. Based on the Phylogenetic studies CVYV were divided into two main groups I (subgroups IA and IB) and II: the first group belongs of isolates from Lebanon and Jordan, Tunisia and Spain, but the second group contained only isolates of Iran (Chabahar) which indicates the high diversity of this isolate. The results of the genetic diversity and selection indices showed that the gene flow from Europe to Asia is very small and the genetic difference is high between them. The CP region is under severe pressure a negative choice, and has caused variation and evolution of the CVYV. Generally, based on the results, the most diversity molecular and host are in Asia group.