Current advances and prospectus of viral resistance in horticultural crops

Viruses are a major threat causing massive yield loss and economical damage to crop production worldwide. Through complex evolutionary processes, plants encounter and overcome viral infection by developing effective resistance mechanisms. Over the past decade, remarkable progress has been made in understanding the nature of plant resistance to viruses at the molecular level. This review summarizes the major resistance strategies that plants use to prevent viral infection. Recent investigations suggest that antiviral RNA silencing is the most prevalent defense strategy in plants. Other forms of resistance include R gene-mediated resistance and host factor-related recessive resistance. Naturally occurring resistances arise and are maintained in numerous virus-plant pathosystems based mainly on arms-race relationships and the cost-efficiency of resistance acquisition. In addition to the current status of the known resistance mechanisms, this review discusses the future prospectus for the practical application of plant resistances that influence resistance durability in agricultural ecosystems. Such applications include molecular breeding strategies using advanced molecular marker systems and the utilization of trans- or cis- genetics via the acquisition of engineered disease resistances.