Common and genotype-specific responses of peach cultivars to chilled storage based on transcriptomic analysis

Both peaches and nectarines are highly valued fruit but deteriorate rapidly at room temperature. Prolonged chilled storage, needed in the supply chain, can result in chilling injury (CI). This physiological disorder is characterized by changes to the texture, color and aroma of the fruit. Nectarines are generally more resistant to CI than peaches, although the effect of chilling is cultivar-dependent. To better understand how CI may be regulated at a transcriptional level, transcriptomes of one peach ('Sagittaria') and one nectarine ('Big Top') cultivar were analyzed at five time points through a 14 day period of chilled storage at 1 degrees C and after an acclimatization phase at 22 degrees C for 36 h. This treatment did not induce symptoms of CI, which at this temperature do not normally develop until about 3 weeks of storage. Overall, differentially expressed genes (DEGs) increased with storage in both cultivars, although more DEGs were found in 'Big Top', and expression changed earlier, perhaps linked to the greater resilience of nectarines. Some of these genes which are activated well before physiological signs of CI may be useful markers to predict CI development during storage.