2017 ASHS Annual Conference

Strawberry fruit, a popular horticultural crop cultivated around the world, is a good source of vitamin C and flavor. Strawberry fruit are highly perishable and easy to weak against Botrytis cinerea thus significant postharvest losses and short shelf-life are major concerns. In order to solve these problems, postharvest technology of short-term high CO₂ treatment has been applied to strawberry fruit to maintain fruit firmness and to prevent fruit decay after harvest. However, postharvest physiological changes and responsive genes induced by high CO₂ have not been clarified yet. By using transcriptome and metabolomic analysis, we first reported new cellular responses caused by high CO₂ in harvested strawberry fruit. Harvested strawberry fruit were stored at 10^oC after 30% CO₂ exposure for 3 h, or air for 3 h respectively. 30% CO₂ showed an effect on inhibiting the fruit decay. Transcriptome analysis showed that the contigs encoding the peroxidase, that is involved in the defense mechanism and transmembrane protein that acts as a receptor for detecting the extracellular signal, were up regulated by 30% CO₂. The contigs that encode pectinesterase and expansin, which are cell wall degradation enzymes, were down regulated by 30% CO₂. Changes in fruit phenotype as well as gene expressions were also observed. At 3 days of storage, pectin content in the cell wall of strawberry fruit treated 30% CO₂ was 46% higher than that in the control fruit. We could presume that high CO₂ increase defense mechanism by activating several antioxidant enzymes and reduce pectin decomposition of cell wall by deactivating cell wall degradation enzyme in strawberry fruit.