Physiological and biochemical responses of grape dormancy breaking with cyanamide and expression analysis of related genes

To explore the responses of physiological and biochemical and mechanism of molecular regulatory for grape dormancy breaking with cyanamide, Vitis vinifera x V. labrusca ‘Shuijing' was used as experimental material in this study to determine the changes in activities of SOD, POD, CAT, contents of MDA and H2O2, and oxygen free radical production rate, and RT-PCR technology was used to clone the full-length cDNA sequences of two FT(Flowering location T)genes(VvFT1 and VvFT2)and one CBF(C-repeat Binding Factor)gene(VvCBF)from its buds, then their physicochemical properties, phylogenetic evolution, conserved motifs and domains, and expression levels differences in grape buds after cyanamide treatment were analyzed. The results were as follows:(1)The analysis of physiological and biochemical indicators showed that activities of SOD, POD and CAT, contents of MDA and H2O2, and oxygen free radical production rate in grape buds were significantly increased after treated with cyanamide.(2)The full-length cDNA sequences of VvFT1 and VvFT2 genes were 525 bp from Vitis vinifera × V. labrusca ‘Shuijing', encoding 174 aa, and the full-length cDNA sequences of VvCBF gene was 826 bp, encoding 237 aa.(3)The homology analysis showed that VvFT1 of Vitis vinifera × V. labrusca ‘Shuijing' had the highest amino acid homology with Litchi chinensis(LcFT: AEU08960.1)and Dimocarpus longan(DlFT2: ALA55998.1), VvFT2 had the highest amino acid homology with LcFT(AEU08961.1)and DlFT2(AHF27444.1). The phylogenetic analysis showed that VvFT1, VvFT2, LcFT(AEU08960.1, AEU08961.1)and DlFT2(ALA55998.1, AHF27444.1)clustered into a branch, with the most closes genetic relationship; VvCBF had the highest amino acid homology with Prunus ledebouriana(PlCBF: AEB69782.1), and the phylogenetic analysis showed that VvCBF and PlCBF clustered into a branch, with the most closest genetic relationship.(4)qRT-PCR analysis showed that VvFT1 and VvFT2 expression levels were significantly increased in buds after treated with cyanamide, while VvCBF expression level was significantly decreased. In summary, this study comprehensively analyzed the phylogenetic evolution of VvFT1, VvFT2, and VvCBF genes, as well as the expression patterns of these genes and physiological and biochemical indicators in grape buds after treated with cyanamide, laying a theoretical foundation for the molecular and physiological mechanisms of grape dormancy breaking with cyanamide.