Altered Environmental Conditions Affect Responses to the Green Leaf Volatile Z-3-Hexenol in Zea mays

Green leaf volatiles (GLVs) are significant volatile signals that have been shown to protect plants against biotic and abiotic stresses, including insect herbivory and pathogen infections, as well as drought, cold, and heat stress. Since all these stresses are affected by climate change, GLVs provide an important target for research into their broad activities and their potential applications in agricultural settings. Therefore, to gain further insights into the protective properties of GLVs and their regulation under changing environmental conditions, we investigated whether climate-related changes alter the capacity to produce and the responsiveness to GLVs in Zea mayss, our model plant. Specifically, we studied the effects of limited nutrient supply, drought, and higher temperature. Neither significantly affected the capacity of plants to produce Z-3-hexenal as the first metabolite of the pathway, but elevated temperature increased E-2-hexenal production. We further identified changes in the effectiveness of plants to respond to GLVs under changing abiotic conditions by monitoring glucose levels and typical GLV-responsive genes covering metabolism, direct defense, indirect defense, and water stress. The results provide first evidence that plant responses to GLVs under defined environmentally challenging and stressful conditions are highly context-dependent and can vary substantially.