miR169 and PmRGL2 synergistically regulate NF-Y complex to active dormancy release in Japanese apricot (Prunus mume Sieb. et Zucc.)

Insufficient chilling requirements affect the floral bud quality and fruit yield in fruit crop production. Endodormancy is a process to meet the chilling requirement. To understand the mechanism of dormancy release in woody plants, we compared the miRNA database during the transition stage from endodormancy to dormancy release in Japanese apricot and found that the miR169 family showed significant differentially up-regulated expression during dormancy and down-regulated during dormancy release periods. The 5 RACE assay and RT-qPCR validated its target gene NUCLEAR FACTOR-Y subunit A (NF-YA) exhibited the opposite expression pattern. Further study showed that exogenous GA4 could inhibit the expression of PmRGL2 and promote the expression of NF-Y. Moreover, the interaction between NF-Y family and GA inhibitor PmRGL2 was verified by yeast-two-hybrid system and Bimolecular fluorescence complementarity (BiFC) experiment. These results suggested that synergistic regulation of NF-Y and PmRGL2 complex to active dormancy release induced by GA4. These will help to elucidate the functional and regulatory roles of miR169 and its target gene of the seasonal bud dormancy induced by GA4 in Japanese apricot woody plants and to provide new sights for the discovery of dormancy release mechanism.