Host plant resistance to TSWV: current status and historical perspective
Massimo Turina, Marina Ciuffo, Paolo Margaria
Istituto di Virologia Vegetale, CNR-Torino. Strada delle cacce 73, 10135 Torino-Italy
Correspondence: m.turina@ivv.cnr.it
Due to the difficulty of controlling the thrip vector, with either chemical or biological control methods, host plant resistance to TSWV is the only economically feasible approach to controlling Tomato spotted wilt virus (Tospovirus, Bunyaviridae). Through traditional breeding programs a variety of resistance genes from different plant species have been introgressed into the vegetable crops most heavily damaged by this virus. We will briefly outline the history of the discovery and the characterization of the two most popular resistance genes: Sw5 in tomato, and Tsw in pepper. Over the years, reports of the presence of resistance breaking strains of TSWV and the resulting disease epidemics have stimulated the search for new resistance genes for both tomato and pepper crops. We will provide an overview of the importance of such epidemic episodes, assess the probability of finding and introgressing new resistance genes, and discuss potential outcomes of such efforts. Additionally, in the case of these resistance breaking strains of TSWV infecting both resistant pepper and tomato plants, the avirulence-resistance gene interaction at the molecular level is of particular interest; we will assess past and recent acquisitions of such an interaction. Most recently, pathogen derived resistance against TSWV has also been experimentally employed: we will report the outcome of the different approaches used for this defense strategy and the possibilities of its open field implementation. The emergence of new Tospoviruses and potential host resistance to such viruses will also be discussed.strategy and the possibilities of its open field implementation. The emergence of new Tospoviruses and potential host resistance to such viruses will also be discussed.
