关键词: 葡萄, 细胞分裂素氧化酶, CKX3, 表达分析

Abstract: Combined with the homologous clone and RACE technology to clone the cytokinin oxidase gene CKX3 in Kyoho grapevine，and analyzes the characteristics of the gene expression and its response to cytokinin. Sequence analysis indicated that CKX3 consisted of 2 049 bp，with ORF of 1 569 bp，encoded 522 amino acids. The deduced amino acids possessed FAD-binding and cytokinin-bining domains. CKX3 gene is located on chromosome 7 in grapevine，this gene contains 4 introns and 5 exons. Multiple sequence alignments and phylogenetic analysis showed that CKX3 had the highest evolutionary relationship with NuCKX3 from Nelumbo nucifera，and had the highest homology with PtCKX3 from Populus trichocarpa. The results at transcriptional level indicated that expression of CKX3 was main in root and inflorescence，the expression in tendril and fruit tissues was higher than that of stem and leavestissues. In inflorescence development process，the expression of CKX3 in blooming before is low，the expression in blooming and blooming later is increased. In the grapevine leaves after 6-BA treatment，the expression of CKX3 and the cytokinin oxidase enzyme activity were higher than that of control.

Key words: grapevine, cytokinin oxidase, CKX3, expression analysis