Viral Diseases of Tomato – Origins, Impact, and Future Prospects with a Focus on Tomato Spotted Wilt Virus and Tomato Yellow Leaf Curl Virus

Abstract

Tomatoes are affected by a number of viruses, with tomato spotted wilt virus (TSWV) and tomato yellow leaf curl virus (TYLCV) being two of the most damaging. TSWV and TYLCV have severely impacted tomato production worldwide for the past several decades at levels that led to both of these viruses being included in the list of top ten most important plant viruses. While they were first described in the early 1900s, both of these viruses emerged in the 1980s to become the severe and persistent problems they are today. The emergence of both viruses was facilitated in part by the emergence and expansion of more efficient insect vectors. Natural sources of resistance, especially from wild relatives of tomato, have provided some measure of control for both viruses to date. This chapter summarizes the origins, emergence, and impacts of these viruses, along with current approaches and future prospects for control, including both natural and engineered resistance.

Advances and Prospects of Virus-Resistant Breeding in Tomatoes

“…In addition to the Sw-5 gene, seven other genes resistant to TSWV belonging to the Sw gene family have been currently identified in tomatoes, and they include Sw-1a, Sw-1b, Sw-2, Sw-3, Sw-4, Sw-6, and Sw-7 (Table 2). The introgression/incorporation of these resistance alleles in the commercial varieties could create materials with broad-spectrum resistance [69]. Molecular markers associated with TSWV resistance in tomatoes were summarized in a previous study that developed more than 20 molecular linkage markers for Sw-5 and Sw-7 TSWV resistance genes [10].…”