During his PhD, Athos Silva de Oliveira has studied the Sw-5 gene cluster from tomato which encodes receptors (NB-LRR proteins) potentially involved in resistance triggering against pathogens. Nevertheless, only one of these receptors, Sw-5b, has been shown functional since it recognizes and activates resistance against tospoviruses. These viruses are thrips(insect)- transmitted and cause substantial losses on vegetal production around the world. In this PhD the genetic delimitations that specify tomato resistance against certain tospoviruses have been investigated. More specifically, why and how these viruses are perceived by Sw-5b and not by other Sw-5 proteins have been elucidated. The evolutionary aspects of this plant-virus interaction are also discussed in light of a new tospovirus species characterization. The outcomes of this research clarify the basis of tomato resistance against tospoviruses which can be applied for the development of more resistant tomato cultivars against those viral pathogens.