Profiling major volatile components in apricot fruit sheds light on the molecular mechanisms underlying low-temperature-mediated volatile release.

Storage of ripe apricot (Prunus armeniaca) fruit at low temperatures results in the loss of volatile aroma compounds. Here, we analyzed volatile compounds in fruit from the apricot cultivars 'Chuanzhihong' and 'Mituoluo' during ripening and identified esters as key contributors to fruit aroma. The cultivars accumulated different profiles of volatiles during ripening. Transcriptome analysis identified more than 20,000 genes that were differentially expressed during fruit development and a cluster of genes that were enriched in KEGG pathways associated with fatty acid-derived ester biosynthesis. The key ester biosynthetic genes LOX and AAT were upregulated during fruit ripening but suppressed at low temperatures. Volatile emissions dropped below 10 °C and partially recovered at 25 °C, but LOX and AAT enzymatic activities failed to recover, leading to diminished aroma. Storage at 0-5 °C caused a strong and largely irreversible suppression of ester accumulation, even after rewarming.