Expression Of Two Genes Associated With Grapebud Dormancy And Changes Of Nitrogen And Anti-oxidation System During The Process Of Dormancy Release

Dormancy is a kind of biological adaptability of perennial woody plants,which is formed responding to the seasonal climate changes in the long-term process of natural evolution. As a perennial woody plant, there are two kinds of buds, latent buds and prompt buds, along shoots of grapevine. Prompt buds can germinate and then develop into shoots in the same year, while latent buds remain dormant to safely overwinter, until the following year, when the environmental condition is suitable for germination. In this study, based on the SSH-cDNA library of latent buds and prompt buds of Cabernet Sauvignon previously constructed by our research group, we cloned two candidate genes using the homology-based cloning and reverse transcription PCR method, and made bioinformatics analysis of them. Also, we detected the gene expression profile using the technique of real-time quantitative PCR under different germination status of both latent buds and prompt buds to confirm the relationship between the genes and bud dormancy. At last, changes of nitrogen and the anti-oxidation system were determined of which were identified to be associated with grapevine bud dormancy, on the purpose of elucidating the molecular machnism of grapebud endormancy and dormancy release. The results are as follows:1. The full length cDNA sequence coding for the auxin-repressed protein(Arp) of Vitis Vinifera.L was obtained. Sequence analysis showed that the deduced protein encoding by VvArp contained the conserved domain of auxin-repressed superfamily and it was proved to be a hydrosoluble non-secreted protein. Neither signal peptide nor transmembrane domain was detected. Real-time PCR detection showed that the relative expression of VvArp varied greatly with the bud break of prompt buds and showed a significant difference between these two kinds of buds even in the same node. VvArp expression was down-regulated with the bud break of latent buds no matter being treated with HC or with clear water. While the VvArp gene expression of the control decreased slowly with the extension of time.2. The full length cDNA sequence of the cyclin-dependent kinase gene(VvCdk) was cloned. Sequence analysis showed that the pupative CDK of Vitis vinifera.L contained the characteristic CDK family signature sequence and conserved dormains. The results of real-time quantative PCR showed that just like the expression of VvArp, the relative expression of VvCdk varied greatly with the bud break of prompt buds and showed a significant difference between these two kinds of buds even in the same node. VvCdk expression was up-regulated with the bud break of latent buds after being treated with HC. While the VvCdk gene expression of the control were consistently lower than that of the treatment, though increased, but slowly with the extension of time.3. After analyzing the hydrogen cyanamide’s impact on the anti-oxidation system, we found that, the content of superoxide anion radical(O2￣?) showed a trend of decreasing and the hydrogen peroxide(H2O2) increased, compared with the control group which were treated with clear water, both of them changed by a bigger margin troughout the bud dormancy breaking process. As for the antioxidant enzymes, the SOD acitivity were on the rise. While, POD and CAT activity were down-regulated. In general, the control group changed less than the treatment group.4. By analyzing the hydrogen cyanamide’s influence on the content of nitrogen compounds, we can conclude that: with the deepening of bud germination, the content of total nitrogen, total protein and the soluble protein in the control group and treatment group both showed a trend of increase, and in comparison, the control were relatively lower and increased more slowly.