Abstract: In order to explore the relationship between spermine synthase（SPMS）and cold resistance of tea plant（Camellia sinensis），the full-length cDNA sequence of SPMS gene was cloned using reverse transcription-PCR（RT-PCR）combined with RACE techniques from tea plant cultivar‘Yingshuang’. This gene was named CsSPMS with GenBank accession number KJ580429. It was 1 374 bp in length，containing a 1 113 bp open reading frame（ORF）which encoded 371 amino acid residues of 41.28 kD molecular weight. The localization assays indicated that CsSPMS protein localized in the cell nucleus，after observing its subcellular localization by the fusion expression vector pJIT166-GFP/SPMS. CsSPMS gene expressed in all the tissues，including root，stem，leaf，flower and fruit analyzed by quantitative real-time PCR（qRT-PCR），the highest expression level were in root and stem. The qRT-PCR analysis also indicated that the expression level of CsSPMS was up-regulated in roots，stems and leaves by cold treatment. The top expression level of CsSPMS in leaves was after 2 h treatment，while after 12 h treatmentin roots. Furthermore，cold resistance of four tea plant cultivars is closely related to expression levels of CsSPMS under low temperature condition.

Key words: tea plant, Camellia sinensis, CsSPMS, subcellular localization, gene cloning, gene expression