Mixed viral infections in vegetable crops: biochemical and molecular aspects

Mixed viral infections refer to the coinfection of two or more viruses in the plant, which regularly lead to exacerbated symptoms on leaves and fruits. The dynamics of coinfections may follow either a synergistic, antagonistic, or neutral interaction that impacts the severity of the symptoms and infection. Mixed viral infections occur due to the convergence of fundamental characteristics reviewed in this manuscript. The virus‒host plant interrelationship influences the establishment and spread patterns of mixed viral infections. Attention should be drawn to potential changes in the dynamics of transmission and prevalence of plant viral diseases due to the effect of anthropogenic and natural alterations to complex agroecological systems or their components, including hosts, reservoirs, vectors, ecological niches, and the emergence of new virus strains.