Preliminary Study On Gene Expression Differences During Cold Acclimation Of Tea Plant

Tea palnt (Camellia sinensis) originated in tropic and subtropical regions ,so that it likes warm and wettish climes and has poor tolerance to low temperature.People have attached more importance to how to advance its cold hardiness resistance in recent years. The increasing investigations show that the series changes of plants during cold domestication are caused by the expression changes of genes and some relative genes are cloned. The research of gene expression changes during cold domestication of tea plant has not be reported until now. The research is very important to the mechanism of cold tolerance. It's very significative to the using of idioplasm resource, introduce of species, breeding and the improve of cultivation technique.The cold tolerances during cold acclimation of tea plant were studied by relative conductivity, It was very sensitive to the changes of temperature.The cold tolerances enhanced with the decrease in temperature and reduced with the increase in temperature. It had different reactions to different low temperatures .It had lower tolerance when the temperature was between biologic temperature and 4℃,and had higher tolerance when the temperature was lower than 4℃.Gene expression differences during cold acclimation of tea plant were preliminary studied by mRNA differential display reverse transcription PCR (DDRT-PCR) to three representational samples. Fifteen differentially expressed cDNA fragments were confirmed by the analysis of RT-PCR,which primers were according to the sequence of differentially expressed cDNA fragments. Among them, nine were increasing, five were reducing and one was increasing in the sample two.Through BLAST, these differentially expressed cDNA fragments were showed homology to nectarinⅢgene of Nicotiana langsdorffii×Nicotiana sanderae(3), glycerophosphoryl diester phospho diesterase family protein gene of Arabidopsis thaliana(48), tubuLin-specific chaperone C-related gene of Arabidopsis thaliana(52), photosystemⅡprotein D1 gene of Camellia sinensis(80,138). Lecithin cholesterol acyltransferase family protein of Arabidopsis thaliana(147), putative cis-zeatin O glucosyl- transferase of Sorghum bicolor(H4), chloroplast gene for chloroplast product of Cucumis sativus(H33), ribulose-1,5-bisphosphate carboxylase/oxygenase small subunit (rbcS) mRNA of Camellia sinensis(H44), respectively, while three showed homologous to Vitis vinifera hypothetical proteins, three show low homologous to all known genes, might be novel genes.Six ESTs were chosen to study the gene expression changes by the analysis of RT-PCR, which primers were according to the sequence of the ESTs. Except FAD6, the other ESTs, metallothionein(MT), water stress and ABA induced protein, Mn-S OD,eraldehyde-3-phosphate dehydrogenase (GAPDH) and cyclophilin had some relationships with cold tolerance.