Plant Response to Biotic and Abiotic Stress: A Study of Adaptation Strategies in Different Glycine max Cultivars

Insects are still the main competitor of humans for food, and combined with other environmental stresses (such as hydric stress), they cause several yield losses and the reduction in crop quality. Therefore, the effects of the herbivory, hydric stress, methyl jasmonate, and the combination of these stresses on Glycine max cultivars resistant and susceptible to Spodoptera cosmioides were investigated. Chemical profile analyses of volatile and nonvolatile compounds from leaves revealed a clear influence of the stress conditions on the plant response according to the cultivar. Plants susceptible to S. cosmioides under hydric stress showed chemical variations characteristic of plant acclimation. Application of methyl jasmonate to the leaves induced resistance responses in both cultivars. The results indicated the activation of pathways such as glycolysis, tricarboxylic acid cycle, oxylipins, phenylpropanoids, and fatty acids. Thus, this study contributes to a molecular understanding of the resistance mechanisms developed in G. max cultivars.