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 characterised 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, with the expression of aphid detoxification genes increasing under drought when feeding on the susceptible plant but decreasing on the partially-resistant plant. Furthermore, we show that the expression of thionin genes, plant defensive compounds that contribute aphid resistance, increase ten-fold in susceptible plants exposed to drought stress but remain at constant levels in the partially-resistant plant, suggesting they play an important role in modulating aphid populations. This study highlights the role of plant defensive processes in mediating the interactions between the environment, plants, and herbivorous insects.

中文翻译：

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干旱胁迫增加大麦防御基因的表达，对感染谷物蚜虫产生负面影响

作物暴露于无数具有负面后果的非生物和生物压力源。预计在气候变化下会增加的两个压力因素是干旱和食草昆虫的侵扰，包括重要的蚜虫物种。在未来的气候情景下，扩大我们对干旱对植物-蚜虫关系的影响的理解将变得越来越重要。在这里，我们使用先前表征的植物 - 蚜虫系统，包括易感的大麦品种、具有部分蚜虫抗性的大麦的野生近缘种和鸟樱桃 - 燕麦蚜虫，以检查干旱 - 植物 - 蚜虫的关系。我们表明干旱对植物生理和蚜虫健康有负面影响，并提供证据表明植物抗性影响蚜虫对干旱胁迫的反应，蚜虫解毒基因的表达在干旱条件下以易感植物为食时增加，而在部分抗性植物上减少。此外，我们表明，硫素基因（有助于蚜虫抗性的植物防御化合物）在暴露于干旱胁迫的易感植物中的表达增加了 10 倍，但在部分抗性植物中保持恒定水平，表明它们在调节蚜虫方面发挥重要作用。蚜虫种群。这项研究强调了植物防御过程在调解环境、植物和食草昆虫之间相互作用中的作用。有助于蚜虫抗性的植物防御化合物在暴露于干旱胁迫的易感植物中增加十倍，但在部分抗性植物中保持恒定水平，表明它们在调节蚜虫种群中发挥重要作用。这项研究强调了植物防御过程在调解环境、植物和食草昆虫之间相互作用中的作用。有助于蚜虫抗性的植物防御化合物在暴露于干旱胁迫的易感植物中增加十倍，但在部分抗性植物中保持恒定水平，表明它们在调节蚜虫种群中发挥重要作用。这项研究强调了植物防御过程在调解环境、植物和食草昆虫之间相互作用中的作用。