Begomovirus menace and its management in vegetable crops

Abstract

Vegetable is the most emerging sector of the horticultural commodity, which contribute not only to nutritional richness but, also on-farm and off-farm income. The begomoviruses, member of geminiviridae family are the largest contributor in devastation of these crops. Tomato, chilli, cassava, okra, cucurbits, and pulse vegetables suffer greatly due to these viruses. The conducive environment, continuous cropping of one or more host crop throughout the year, emergence of new viruleferoius vectors biotypes, and evolution of new recombinant virus strains are the most important factors in the spread of these diseases. The begomoviruses are either mono or bipartite, can be associated with alpha or betasatellite DNA, which has role in symptom development and virulence. Management of virus vector should be the major strategy to inhibit the contact between host and pathogen. Cultural practices like, removal of alternate hosts, destruction of unwanted weeds, and uprooting and burning of initially infected plants are commonly practiced. Management of sucking pest, mainly whitefly at regular interval with insecticide significantly reduces the chances of transmission of these viruses, however insecticide resistance is frequently observed among these group of pests. The viable and naturally safe method to control these diseases is through host plant resistance, by identification and transfer of resistance governing genes in cultivated backgrounds. Transgenic approaches targeting viral genes are also widely used for development of resistant lines. The most recent technology like genome editing with CRISPR/Cas-9 was also found promising in development of resistant tomato and cassava lines however, its widespread use is limited due to unavailability of information about susceptibility genes in several crops.