Abstract:The full length cDNA of the key ratelimiting enzyme gene CsNCED2 (9cisepoxycarotenoid dioxygenase, NCED) in the ABA synthesis pathway was cloned by RTPCR from the leaves of tea cultivar ‘Tieguanyin’ in this study. The full length cDNA was 1 931 bp with an ORF of 1 821 bp, encoding 606 amino acids with 78% homologous of the NCED2 from Vitis vinifera, named as CsNCED2. Amino acid sequence analysis showed that CsNCED2 contains three conserved domain FLNO2258, MIAHPKxDP and HDFAITE, being the characteristic feature of NCED gene families. It possessed four conserved histidine residues requiring Fe2+ binding site and Nterminal chloroplast targeting transit peptides. Quantitative PCR analysis showed that the expression of CsNCED2 was highly in leaf, stem and flower. White and Oolong tea processing procedure could significantly upregulate the expression of CsNCED2. The expression of CsNCED2 was significant upregulate under the treatment of ABA and cold, but repressed by drought. In conclusion, CsNCED2 might play an important role in the ABA synthesis metabolism and the responses to different stress in tea plant.