PmSOC1s and PmDAMs participate in flower bud dormancy of Prunus mume by forming protein complexes and responding to ABA

Flowering time is an important agronomic trait, which can affect the fruit -bearing and ornamental value of plants. Being a perennial woody horticultural plant in the temperate zone, the flowering time of Prunus mume is deeply affected by the dormancy duration. It is well known that MADS-box transcription factors play vital roles in the flowering time and dormancy processes, such as SUPPRESSOR OF OVEREXPRESSION OF CONSTANS 1 (SOC1) and Dormancy Associated MADS-box (DAM) genes. Here, the expression patterns of PmSOC1s and PmDAMs and their relationships with the ABA content in flower bud dormancy were analyzed. They had a similar expression trend, which gradually decreased in the process and positively correlated with the content of ABA. Besides, several ABA-responsiveness elements were predicted in promoter sequences of PmSOC1s and PmDAMs. The expression level of PmSOC1s and PmDAMs under ABA treatment was detected by qRT-PCR. Results showed that PmS0C1-Z, PmSOC1-3 and PmDAM6 were highly sensitive to ABA. Moreover, PmSOC1-1, PmSOC1-2, PmSOC1-3 were detected in the nucleus of the cells in the Nicotiana benthamiana leaves through transient transformation. Furthermore, the results of yeast two -hybrid showed that there was a strong interaction between PmSOC1-2 and PmDAM6. Our results indicated that PmS0C1s and PmDAMs participated in flower bud dormancy by forming protein complexes, and were regulated by ABA, which laid a foundation for elucidating the common mechanism of flowering and dormancy of P mume.