Identification of viruses infecting cucurbits and determination of genetic diversity of Cucumber mosaic virus in Lorestan province, Iran

Abstract

Various viral pathogens infect Cucurbitaceae and cause economic losses. The aim of the present study was to detect plant viral pathogens including Cucumber mosaic virus (CMV), Cucumber green mottle mosaic virus (CGMMV), Zucchini yellow mosaic virus (ZYMV), Cucurbit yellow stunting disorder virus (CYSDV) and Cucurbit chlorotic yellows virus (CCYV) in Lorestan province, in western Iran, and also to determine CMV genetic diversity in Iranian populations. A total of 569 symptomatic leaf samples were collected in 2013 and 2014 from cucurbits growing regions in Lorestan province. The collected samples were assessed for viral diseases by ELISA. The results showed virus incidences in most regions. Then, the infection of 40 samples to CMV was confirmed by RT-PCR. Moreover, to distinguish between the two groups (I and II) of CMV, PCR products were digested by two restriction enzymes XhoI and EcoRI. Results of the digestion showed that the isolates of Lorestan belonged to group I. The CMV-coat protein gene of eight isolates from different regions and hosts was sequenced and phylogenetic analysis was performed. Subsequent analyses showed even more genetic variation among Lorestan isolates. The phylogenetic tree revealed that Lorestan province isolates belonged to two IA and IB subgroups and could be classified together with East Azerbaijan province isolates. The results of the present study indicate a wide distribution of CMV, ZYMV, CGMMV, CYSDV and CCYV viruses in cucurbits fields of Lorestan province and for the first time subgroup IB of CMV was reported on melon from Iran.