Search

Aphids are important herbivorous insects that can cause significant crop damage, leading to yield reduction and economic loss. One avenue being explored to reduce aphid impacts is the development of aphid-resistant plants. Under projected climate scenarios, it is expected that plants will be exposed to greater biotic and abiotic stress, including increased herbivorous insect infestation and exposure to prolonged periods of environmental stress, particularly drought. In response to these projections, plant–aphid interactions under drought conditions have been a subject of growing interest; however, few studies have looked at the impact of drought stress on plant resistance to aphids despite the potential importance for plant breeding. Here, we examine the latest scientific advances regarding variation in plant resistance to aphids under drought, emphasizing underlying mechanisms and functional trade-offs and propose a conceptual model relating plant tolerance to drought with plant resistance to aphids. [ABSTRACT FROM AUTHOR]

Crops are exposed to myriad abiotic and biotic stressors with negative consequences. Two stressors that are expected to increase under climate change are drought and infestation with herbivorous insects, including important aphid species. Expanding our understanding of the impact drought has on the plant–aphid relationship will become increasingly important under future climate scenarios. Here we use a previously characterized plant–aphid system comprising a susceptible variety of barley, a wild relative of barley with partial aphid resistance, and the bird cherry-oat aphid to examine the drought–plant–aphid relationship. We show that drought has a negative effect on plant physiology and aphid fitness, and provide evidence to suggest that plant resistance influences aphid responses to drought stress. Furthermore, we show that the expression of thionin genes, plant defensive compounds that contribute to aphid resistance, increase in susceptible plants exposed to drought stress but remain at constant levels in the partially resistant plant, suggesting that they play an important role in determining the success of aphid populations. This study highlights the role of plant defensive processes in mediating the interactions between the environment, plants, and herbivorous insects. [ABSTRACT FROM AUTHOR]