Beitrag
Tritrophic implications of drought on plant-insect-pathogen interactions
Pan, Qinjian; Shikano, Ikkei; Hoover, Kelli; Felton, Gary W.
Online veröffentlicht: Jun 10, 2026
Manuskript akzeptiert: Mar 19, 2026
finale Ms. Revision erhalten: Jan 13, 2026
Manuskript-Revision angefordert: Dec 17, 2025
Manuskript erhalten: Sep 30, 2025
Abstract
Drought can alter the chemical and physical characteristics of plants, which may trigger cascading effects on other trophic levels. Here, cotton plants were subjected to two watering regimens (high and low) and the plants’ resistance to a generalist insect herbivore, Helicoverpa zea, were examined. Since plant nutritional and allelochemical properties are known to impact the outcomes of interactions between H. zea and a highly pathogenic baculovirus, H. zea single nucleopolyhedrovirus (HzSNPV), we exposed H. zea larvae to the virus on foliage from amply watered and water-restricted plants. We found that water stress conditions decreased plant growth and increased foliar protein content and peroxidase activity. Larval growth was significantly faster on water-restricted plants than on amply watered plants, while induction of plant defenses with prior larval feeding damage suppressed larval growth on amply watered plants but not on water-restricted plants. HzSNPV-induced mortality was significantly affected by both plant watering regimen and prior herbivory. Caterpillar-induced defenses in cotton reduced viral mortality when the virus was ingested on leaves from amply watered plants but increased mortality under water stress conditions. Moreover, HzSNPV-infected larvae feeding on leaves from water-restricted plants produced more viral occlusion bodies (OBs) and increased the efficiency of conversion of host tissue into OBs. Our findings demonstrate that water stress can reshape the impacts of herbivore-induced plant defenses on insect-pathogen interactions. As the frequency and severity of droughts change, the effects on plant physiology could have profound effects on pathogen-mediated insect population dynamics and the efficacy of microbial biocontrol of pest insects.
Schlagworte
baculovirus •
Helicoverpa zea
•
herbivore-induced plant defenses •
multitrophic interactions •
virus-induced mortality •
water stress