Photoperiod- and Temperature-Mediated Control of the Ethylene Response and Winter Dormancy Induction in Prunus mume

ABSTRACT Plant dormancy is essential for perennial plant survival. Different genotypes of Prunus mume, including Eumume group and Apricot Mei group, undergo leaf senescence and dormancy at different times. In order to verify the cold resistance of P. mume, freeze resistance evaluation was carried out. Our results showed that Apricot Mei group had a stronger freezing tolerance than Eumume group and that leaf senescence and dormancy of Apricot Mei group occurred at an earlier period before winter. Based on phenotypic data in response to seasonal climate change, the significant candidate regions were selected using GWAS. Furthermore, through KEGG pathway and qRT-PCR analyses, we found that the ethylene-related genes, including PmEIL (Pm002057) and PmERF (Pm004265), were significantly upregulated in ‘Songchun’ Mei (Apricot Mei group) and downregulated in ‘Zaohua Lve’ Mei (Eumume group). Ethylene-related genes expression models showed that ethylene may be indirectly involved in the induction of dormancy. The PmEIL and PmERF genes were the core genes of the ethylene signal transduction pathway and were regulated by the exogenous ACC or PZA compounds. For non-dormant or weekly dormant perennial plants, application of ACC was able to induce plant dormancy and thus enhance cold/freeze tolerance. Overall, the expression of the major ethylene genes played a significant role in dormancy induction and freezing tolerance in P. mume; accordingly, application of ACC and PZA compounds were an effective approach for enhancing cold/freeze of tolerance of woody plant.