Secreted effectors of Helicoverpa zea induce tomato defense

When herbivorous insects feed on plants, their oral secretions inevitably come in contact with the wounded plant tissue. Although the regurgitant of caterpillars often contains potent elicitors of plant defenses, our previous research has shown that saliva contains effectors that suppress plant defenses. In this presentation, I extend this work to look at the role of saliva in mediating defenses using the noctuid Helicoverpa zea and tomato as a model system. In this study, I examine the role of saliva in mediating jasmonate-regulated defenses and glandular trichome production. As opposed to other host plants (e.g., tobacco, Medicago), my research shows that saliva induces JA-pathway genes and glandular trichome density in newly emerging leaves. I also report, for the first time, the role of herbivory and saliva in mediating defenses in the tomato fruit, the main target for food production. This study provides an example of effector-triggered immunity which has been rarely reported in studies on plant-herbivore interactions.