Detection and Molecular Characterization of Two Potyvirus Species on Cucurbits from Northwestern of Iran

Cucurbit crops belonging to the family Cucurbitaceae are one the most important horticultural crops worldwide and cultivated widely in Iran. To aim detection and phylogenetic analysis of potyvirus members, during 2015-2016, 215 leaf samples from cucumber, melon, watermelon, and squash symptomatic with deforming and reduction in leaf size, blistering, mild and severe mosaic, fruit deformation, and stunting were collected from 10 major cucurbits-growing locations in West Azerbaijan province. Following mechanical inoculation of Cucurbita pepo as an indicator plant with symptomatic cucurbit crop extracts, a variety of symptoms developed on the plants. Then, total RNA extracted from 70 symptomatic leaf samples, and partial RNA-dependent RNA polymerase (NIb) (350 bp) was amplified using universal primer pairs (NIb2F/NIb3R) by reverse transcription-polymerase chain reaction (RT-PCR). The infection by potyviruses in 38.75% of the samples was confirmed based on the result. The five PCR products belonging to different hosts at the expected size (350bp) were sequenced. One sample (Ir-Na: MH491979) was determined to be infected by the Watermelon mosaic virus (WMV) whereas four samples (Ir-Ma:MH491979, Ir-Ng:MH491980, Ir-Pi:MH491981, and Ir-Ur:MH491982) infected by Zucchini yellow mosaic virus (ZYMV). In the phylogenetic analysis based on Maximum-likelihood, three ZYMV isolates (Ir-Ng, Ir-Pi, and Ir-Ur) were placed in subgroup I whereas one isolate (Ir-Ma) was placed in subgroup II belonging to group A. Also, WMV isolate (Ir- Na) was placed in CL phylogroup.