Abstract: The full length cDNA sequence of cyclin-dependent kinase gene was cloned by SMART-
RACE-PCR from tea plant（Camellia sinensis L.），which was named as CsCDK1（GenBank Accession No. JF449383）. Its expression pattern during the time of bud dormancy and bud break in tea plant was analyzed by quantitative real-time PCR（qRT-PCR）. The full length cDNA of CsCDK1 is 1 245 bp，which includes 924 bp complete CDS and encodes 307 amino acid residues with a putative molecular mass of 34.52 kD. The bioinformatics characterization indicated that the protein encoded by CsCDK1 gene has a typically conserved domain and 3D structure of B type CDK family，and it had the highest identity（96%）with CDK of Actinidia chinensis，and it shared over 80% amino acid sequences similarity with CDKs of other plants. The results of quantitative real-time PCR showed that the expression levels of CsCDK1 at dormant stages were lower than growth stages，and the highest expression lever appeared at sprouting stage. It indicates that CsCDK1 has very close relationship with tea plant budbreak in spring.

Key words: tea plant, Camellia sinensis, bud, break, cyclin-dependent kinase gene, expression analysis