Salinity stress alters plant-mediated interactions between above- and below-ground herbivores

Below-ground herbivore impacts plant development and often induces systemic responses in plants e.g., affecting the performance and feeding behavior of above-ground herbivores. Meanwhile, pest-damaged root tissue can enhance a plant susceptibility to abiotic stress such as salinity. Yet, the effect to which herbivore-induced plant defenses are modulated by such abiotic stress has rarely been studied. In this study, we examine whether root feeding by the turnip moth, Agrotis segetum affects the performance of the above-ground, sap-feeding aphid Aphis gossypii on cotton, and assess whether those interactions are modulated by salinity stress. To gain mechanistic insights, we performed transcriptional and metabolic analyses, along with insect bioassays with artificial diets that supplemented with different amino acids content. This study will advance our understanding of how plants cope with concurrent biotic and abiotic stressors, and may help tailor plant protection strategies to varying production contexts.