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Research Project: Basic and Applied Approaches for Pest Management in Vegetable Crops

Location: Vegetable Research

Title: Begomovirus transmission to tomato plants is not hampered by plant defenses induced by Dicyphus hesperus Knight

item LEGARREA, SAIOA - University Of Georgia
item LATORA, ANGELA - University Of Georgia
item Simmons, Alvin
item SRINIVASAN, RAJAGOPALBABU - University Of Georgia

Submitted to: Viruses
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/8/2024
Publication Date: 4/10/2024
Citation: Legarrea, S., Latora, A.G., Simmons, A.M., Srinivasan, R. 2024. Begomovirus transmission to tomato plants is not hampered by plant defenses induced by Dicyphus hesperus Knight. Viruses. 16(4), 587.

Interpretive Summary: When plants are fed on by insect pests and are infected by plant viruses, the plant can produce certain chemicals that make the plant more resistant to pests and infections. The mirid insect Dicyphus hesperus is both a predator of insect pests (including whiteflies) and it also feeds by sucking sap from plant stems. An experiment was done to determine if this predator/plant feeder affects the transmission of the tomato yellow leaf curl virus in tomato plants. Although fewer whiteflies settled on plants that were exposed to the predators, virus acquisition and transmission were the same as plants which did not have predators. These results help researchers in understanding the impact on plant resistance by insect predators that are also plant feeders.

Technical Abstract: Plants can respond to insect infestation and virus infection by inducing plant defenses, generally mediated by phytohormones. Moreover, plant defenses alter host quality for insect vectors with consequences for the spread of viruses. In agricultural settings, other organisms commonly interact with plants, thereby inducing plant defenses that could affect plant-virus-vector interactions. For example, plant defenses induced by omnivorous insects can modulate insect behavior. This study focused on tomato yellow leaf curl virus (TYLCV), a plant virus in the genus Begomovirus and family Geminiviridae. It is transmitted in a persistent circulative manner by the whitefly Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae), posing a global threat to tomato production. Mirids (Hemiptera: Miridae) are predators of B. tabaci and other insects, but there is a possibility that their omnivorous nature could also interfere with the process of virus transmission. To test this hypothesis, this study first addressed to what extent the mirid bug Dicyphus hesperus Knight induces plant defenses in tomato. Subsequently, the impact of this plant-omnivore interaction on the transmission of TYLCV was evaluated. Controlled cage experiments were performed in a greenhouse setting to evaluate the impact of mirids on virus transmission and vector acquisition. While we observed a reduced number of whiteflies settling on plants exposed to D. hesperus, the plant defenses induced by the mirid bug did not affect TYLCV transmission and accumulation. Additionally, whiteflies were able to acquire comparable amounts of TYLCV on mirid-exposed plants and control plants. Overall, the induction of plant defenses by D. hesperus did not influence TYLCV transmission by whiteflies on tomato.