Recombination Among Begomoviruses on Malvaceous PlantsLeads to the Evolution of Okra Enation Leaf Curl Virus in Pakistan

Abstract

Whitefly transmitted begomoviruses (family Geminiviridae) are the majorreason for significant yield losses of dicotyledonous crops in tropics andsubtropics. Okra (Abelmoschus esculentus) is one of the important vegetablecrops, and leaf curl disease caused by geminiviruses is the most importantlimiting factor for its production in Pakistan. Here, we report a new speciesof okra-infecting begomovirus in south-eastern region of Pakistan and thename Okra enation leaf curl virus (OELCuV) complex is proposed. This okraenation leaf curl disease complex (OELCuD) in Pakistan is found to beassociated with Ageratum conyzoides symptomless alphasatellite (ACon-SLA). All efforts to clone the betasatellite were unsuccessful. Comprehen-sive sequence analyses suggest that intermalvaceous recombinationbetween okra and cotton-infecting begomoviruses resulted in the evolu-tion of the new species. Surprisingly, Bhendi yellow vein mosaic virus (BY-VMV) which has not been reported previously from Pakistan is the majorparent while Cotton leaf curl Multan virus (CLCuMV) acts as a distant parentof the virus. Comparative recombination analysis also reveals that okra-infecting begomoviruses from south and north-western India is causingOELCuD in the Pakistan by recombining with CLCuMV at the Rep (1964–1513 nts). Recombination is common among geminiviruses and recom-bining of BYVMV and CLCuMV resulted in a new species: OELCuV. Tothe best of our knowledge, this evolution of a new species of okra-infect-ing begomovirus is the first report of intermalvaceous recombinationwhere Rep acts as the target region