Elevated atmospheric CO₂ concentrations alter grapevine (Vitis vinifera) systemic transcriptional response to European grapevine moth (Lobesia botrana) herbivory

Atmospheric carbon dioxide (CO₂) concentrations are among the chief factors shaping the mode and magnitude of interactions between plants and herbivorous insects. Here, we describe the first global analysis of systemic transcriptomic responses of grapevine Vitis vinifera plants to feeding of European grapevine moth Lobesia botrana larvae at future elevated CO₂ concentrations. The study was conducted on mature, fruit-bearing grapevine plants under ambient and elevated CO₂ concentrations in a grapevine free-air carbon dioxide enrichment (FACE) facility. Grapevine transcriptional response to herbivory was clearly dependent on phenological stage, with a higher number of differentially expressed genes identified at fruit development compared to berry ripening. At fruit development, more transcripts were differentially expressed as a response to herbivory under elevated compared to ambient CO₂ concentrations. Classification of the respective transcripts revealed that in particular genes involved in metabolic pathways, biosynthesis of secondary metabolites and plant-pathogen interactions were significantly enriched. Most of these genes had similar expression patterns under both CO₂ concentrations, with a higher fold-change under elevated CO₂ concentrations. Differences in expression levels of a subset of herbivory responsive genes were further validated by RT-qPCR. Our study indicates that future elevated CO₂ concentrations will affect interactions between grapevine plants and one of its key insect pests, with consequences for future relevance of L. botrana in worldwide viticulture.