Environmental changes and their impact on green leaf volatile production and responses in maize

Green leaf volatiles (GLVs), 6-carbon compounds that are produced through lipid peroxidation, are significant volatile signals that have been shown to protect plants against biotic and abiotic stresses including insect herbivory, pathogen infections, drought, cold, heat, and light. Since all these stresses are affected by climate change, GLVs provide an important target for research into their broad protective activities, which are unrivaled. To gain further insights into the protective properties of GLVs and their regulation, we have begun to study the effects of altered environmental conditions on the production of these compounds as well as their responses while growing under various stressors. We focused on biotic and abiotic responses, since both are intricately connected in a changing environment caused by climate change. We found, for example, that while drought and cold did not significantly affect the capacity to produce Z-3-hexenal as the first metabolite of the pathway, heat did reduce the capacity but also changed the ratios of Z-3-hexenal and E-2-hexenal. In contrast, light did cause a significant increase in the capacity to produce GLVs. Nutrients, as an important factor for growth and yield, also influenced the production of these compounds. We have further identified changes in the effectiveness of plants to respond to these compounds under changing abiotic conditions. In conclusion, our results clearly show an effect of different abiotic and biotic stressors on the capacity of maize plants to produce and respond to GLVs, as a consequence of changes in the environment caused by climate change. The implications of these first findings on the biological properties of these multifunctional compounds and their robustness to changes in the abiotic and biotic environment caused by climate change will be discussed.