Abstract:

In this study，we analyzed the protein sequences and conserved motif of four apple MdCYP707A family members，and found that the four MdCYP707A family proteins contained a cytochrome P450 monooxygenase domain. The expression levels of the four genes in different tissues （roots，stems，leaves，flowers，fruits，and seeds）were detected by real-time qPCR，and they exhibited the highest level in the seeds. The expression pattern of MdCYP707As also showed significant difference during fruit developmental stages. We also examined the transcription level of the MdCYP707A family members in the process of water swelling and stratification of apple seeds，and found that the MdCYP707A family members were involved in the degradation of ABA during seed germination. Furthermore，the response of MdCYP707A genes to abiotic stresses（such as drought，salt，osmotic stress）and ABA treatments indicated their important roles in seed germination，among them，the response to ABA is most obvious. In addition，the function of MdCYP707A1 gene was identified through Agrobacterium-mediated genetic transformation to apple calli and Arabidopsis. The results demonstrated that overexpression of MdCYP707A1 reduced the resistance to abiotic stress，which suggests that it may be involved in ABA degradation，and ectopic expression of MdCYP707A1 in Arabidopsis increased the germination rate.

Key words: apple, MdCYP707A family gene, ABA, abiotic stress, expression analysis