| The developmental process is directly related to the yield and quality of wheat,and histone modification mediated gene regulation plays important roles during the developmental regulation in wheat.In our previous studies,it was found that the SDG proteins are functional enzymes,which involved in the histone methylation.It has been proved that SDG7 and SDG8 take part in the methylation of H3K36,which was closely associated with the development regulation in wheat.Based on our preliminary studies,systematic analysis of the characteristics of Ta SDG7/8 and their differences among alleles in A,B and D genome were conducted,their temporal and spatial expression patterns were characterized,and their functional validation were performed via transgenic methods.The main results are as follows:1.Based on cDNA sequence analysis of wheat histone methyltransferase gene TaSDG7 and Ta SDG8,the characteristics of genomic sequence of the two genes were analyzed in the Chinese Spring,Jing 841 and Luohan 2.The results showed that the Ta SDG7 gene contains eleven introns and locates on the long arm of the seventh chromosome.The Ta SDG8 contains thirteen introns,and locates on the short arm of the second chromosome.2.The expression analysis indicated that TaSDG7 and TaSDG8 was both up-regulated under the cold treatment for vernalization in Chinese Spring and Jing 841,the expression of Ta SDG7 were stably increased during the cold accumulation in Chinese Spring,while showed an wave pattern with time cycle of about 9 days in Jing 841.The expression of Ta SDG8 was also introduced by vernalization treatment,while its expression patterns were different between these two varieties and it seems that it was more sensitive to vernalization treatment in Chinese Spring.These results indicated that these two genes play important roles during the regulation of flowering in wheat.3.The plant over expression vectors for TaSDG8 and TaSDG7 were constructed and used in the functional recovery of Arabidopsis thaliana mutants.The preliminary results show that the Ta SDG8-2 can partially recover the disorder phenotype of the Arabidopsis double mutant sdg7/8,which indicates that the Ta SDG8 functioned during the flowering regulation via histone methylation pathway.The further functional validation experiments are still in progress.4.In order to make a further functional verification of these two SDG genes in wheat,silencing vectors of these two genes,including BSMV-VIGS and RNAi vectors were constructed and used in the transformation characterization.So far,we have obtained the RNAi transgenic materials in the T0 generation of wheat and the subsequent studies on molecular characterization and functional analysis are still in progress. |
