Maintaining the nutritional and functional quality of blueberries during cold storage remains a postharvest challenge. This study evaluated the effects of short-term high-CO2 treatments on phenylpropanoid-related metabolism in two commercially important blueberry cultivar–season combinations: Duke (Vaccinium corymbosum L., highbush; early-season, June harvest) and Ochlockonee (V. virgatum Aiton, rabbiteye; late-season, September harvest). Fruits were exposed to 15% or 20% CO2 for 3 days at 1 °C and subsequently stored for up to 29 days at 1 °C. Phenolic compounds, antioxidant capacity, and the expression of selected phenylpropanoid-related genes, including flavonoid biosynthetic enzymes and R2R3-MYB transcription factors, were analyzed. Short-term CO2 treatments were associated with transient transcriptional responses, particularly in anthocyanin-related pathways, together with genotype-associated differences in phenolic composition and antioxidant capacity during storage. Overall, the results indicate associations between CO2 exposure and secondary metabolism under cold storage conditions and should be interpreted as correlative rather than mechanistic evidence of priming.
Toledo-Guerrero et al. (Thu,) studied this question.