A Biologically Distinct Isolate of Cucumber mosaic virus from Iraq

Abstract

Distinct virus-related symptoms have been recently observed on greenhouse-grown cucumber leaves in different locations of Baghdad's growing area. The symptoms were mainly severe mosaic, stunting, and leaf deformation. Biological data in this study indicates that the virus causing these symptoms is an isolate of Cucumber mosaic virus (CMV). The virus was found mainly on cucumber, and its fast spread in greenhouses caused significant losses to the cucumber marketing value last year. Mechanical inoculation of three symptomatic cucumber leaves out of sixty samples has produced local lesions followed by mosaic on cucumber (Cucumis sativus) and large necrotic local lesions on Cowpea (Vigna unguiculata). The necrotic lesions on cowpea are distinguishable. Although CMV has been previously characterized by infecting cucumber in different areas in Iraq, this isolate is the first and only local isolate found to cause necrotic local lesions on cowpea. We hypothesize that this is a newly introduced strain to the Iraqi environment. This new strain of CMV may thus pose a new threat to cucumber production in Iraq.