Cloning And Expression Of Vernalization Gene VRN1 And DNA Methyltransferase Genes In Wheat

The vernalization gene VRN1 was cloned by RT-PCR and its allelic composition and their expression characteristics were analized. Four different varieties with different dominant VRN1 allelics were used to hybrid with four varieties with ressesive VRN1 loci,and the phenotypes of the F1 generation were analyzed. Five DNA methyltransferase genes were cloned in wheat and their temperal and special expression patterns were also characterized. The main results were summarized as follows:1.Three VRN1 alleles (VRN-A1, VRN-B1and VRN-D1)were analyzed by RT-PCR technique and sequence specific primers were designed for characterization the allelic expression profiles leaves of common wheat plants at the different leaf ages. The results showed that The Vrn-A1,Vrn-B1and Vrn-D1 were expressed in each period in Liaochun No 10 at different vernalization treatments。In the 10 d vernalization treatment and 20 d vernalization treatment, the expression level gradually increased. 30 d vernalization treatment at the time, Vrn-A1, Vrn-B1 and Vrn-D1 expression at various times was no significant difference, vernalization had little effect on expression. The vernalization treatment enhanced the expression of Jing 841 of vrn1, the impact strength with the vrn-A1> vrn-B1> vrn-D1 trend.2. The hybrid tests were performed using four spring wheat varieties, Liaochun No 10, Xinchun No 2, Zhengmai 9023 and Yumai 18, which were crossed with four winter cultivars, Yumai 18, Yumai 49-198, Jing 841 and Xindong 22. Then the dominant VRN1 loci were introduced into the ressecive background and their phenotypes were analyzed. The results showed that the dominant allelic VRN1 genes were successfully introduced into the F1 plants and their seedling-heading period were generally shorted due to the introduction of these dominant allelic sites. The strong heterosis was observed in 8 reciprocal cross between varieties in agronomic characters as plant height, spike length, grains per spike, t1000-grain weight and Spike-types. Especially the Xindong 22 and Yumai 18 heterosis hybrid F1 generation have strong heterosis.These results provide important information for the further cross breeding practice focused on the genetically modification of vernalization and cross breeding in wheat..For example, in the hybrid F1 generation, the spring characteristics of the parents disappeared longearistata, Infer characteristics of recessive genes control the longearistata, and further confirms the need to look at the segregation of their offspring。3. Based on the bioimformatic analysis of the methyltransferase gene sequences in Arabidopsis thaliana and other crop plants, the gene specific primers were designed and five methyltransferase genes were cloned by using RT-PCR amplification technique in wheat, which were termed as TaCMT,TaMETB,TaMET3,TaMET5 and TaMET4. The alignment of wheat methyltransferases deduced from cloned genes, as well as methyltransferases reported in Arabidopsis thaliana, were performed and a phylogenetic tree were maped. It is showed that cloning of wheat methyltransferase Amino acid cluster analysis, then establish the phylogenetic tree, the results show that,TaCMT was higher similarity with AtCMT3, and TaMET2 was closely related to AtDNMT2, TaMET3 and TaMET5 were closely related to AtDRM1 ; TaMET4 was closely related to AtDRM2,.In the cloning of 5-methyl-transferase gene of wheat between, TaMET3, TaMET5 and TaMET4 share closer relationship ,TaMET3 was closely related to TaMET5 .The expression pattrerns of the cloned methyltransferase genes were characterized in two Liaochun No.10 and Jing841, and the results indicated that their expressions were generally repressed or delyed after vernalization treatment. It seemed that the vernalization treatment repressed the expression of methyltransferase genes in wheat.