Elevated CO2 influences herbivory-induced defense responses of Arabidopsis thaliana

We experimentally demonstrate that elevated CO2 can modify herbivory-induced plant chemical responses in terms of both total and individual glucosinolate concentrations. Overall, herbivory by larvae of diamondback moths (Plutella xylostella) resulted in no change in glucosinolate levels of the annual plant Arabidopsis thaliana under ambient CO2 conditions. However, herbivory induced a significant 28–62% increase in glucosinolate contents at elevated CO2. These inducible chemical responses were both genotype-specific and dependent on the individual glucosinolate considered. Elevated CO2 can also affect structural defenses such as trichomes and insect-glucosinolate interactions. Insect performance was significantly influenced by specific glucosinolates, although only under CO2 enrichment. This study can have implications for the evolution of inducible defenses and coevolutionary adaptations between plants and their associated herbivores in future changing environments.