Jasmonate Activated PuCBF5 to Increasing Ester Accumulation in Cold-stored 'Nanguo' Pear Fruit

'Nanguo' pear is a distinctive fruit from Liaoning Province and is highly appreciated by consumers. However, its aroma quality has been observed to diminish after cold storage. Methyl jasmonate (MeJA) is a plant hormone that can promote the esters accumulation in fruits while the exact molecular mechanisms still unclear. In this study, the expression of ester degradation gene PuCXE15 decreased in the cold-stored 'Nanguo' pear with MeJA treatment. MeJA may regulate the metabolism of esters through the CBF (C-repeat binding factor) pathway. Five CBF members were identified in 'Nanguo' pear, among which PuCBF5 was responsive to MeJA. PuCBF5 is a nuclear-localized transcription factor and a positive regulator of ester metabolism. Further experiments showed that PuCBF5 could inhibit the transcriptional activity of PuCXE15 and thus inhibit the degradation of esters. The results provide important insights into the transcriptional control of volatile ester metabolism in 'Nanguo' pear.