关键词: 苹果, MdCKX7.2, 基因克隆, 非生物胁迫, 耐旱性, ABA敏感性

Abstract: MdCKX7.2 gene（MDP0000279125）was cloned from Malus × domestica Borkh‘Gala’using homologous cloning and RT-PCR. The gene contained a 1 542 bp complete open reading frame（ORF）and encoded 513 amino acids. The cis-acting elements of the MdCKX7.2 promoter were analyzed using the Plant CARE database. It was found that there were elements including light，drought，abscisic acid，salicylic acid，and methyl jasmonate in the MdCKX7.2 promoter sequence. Expression analysis revealed that the transcription of MdCKX7.2 in‘Gala’seedlings was significantly induced by drought and ABA treatments. MdCKX7.2 transgenic Arabidopsis plants were obtained by Agrobacterium-mediated genetic transformation. The stress tolerance assays showed that ectopic expression of MdCKX7.2 significantly increased the tolerance of transgenic Arabidopsis to drought stress. Arabidopsis seed germination experiments showed that ectopic expression of MdCKX7.2 in Arabidopsis enhanced the sensitivity of Arabidopsis to ABA，the seed germination rate and seedling fresh weight decreased significantly，and the expression level of genes related to seed germination was significantly up-regulated. The above results indicate that MdCKX7.2 plays an important role in plant abiotic stress response.

Key words: apple, MdCKX7.2, gene clone, abiotic stress, drought tolerance, ABA sensitivity