Glutenin And Gliadin Genes Cloning From Dasypyrum Villosum And Powdery Mildew Resistance Breeding In Wheat

Dasypyrum villosum is an important resource for improving the quality of the flour in bread wheat.The complete coding sequence of two HMW-GS and oneγ-gliadin genes were amplified from the genomic DNA of D.villosum.They were designated Dv-1,Dv-2 and Dv-γrespectively.Dv-1(960 bp) and Dv-2(1158 bp) genes were intron-less y type subunit,although Dv-1 gene contains only 3 cysteine residues in the N-terminal region.The length of Dv-γis 894 bp,and is highly similar to knownγ-gliadin sequences in both nucleotide and deduced peptide sequences.It has five domains and 8 conserved cysteine residues.Phylogenetic analysis revealed that the deduced peptide sequences of the two D.villosum Glu-v1 genes were closely related to that of the StH genome of Elymus ciliaris.Dv-γis clustered to subclass I.The number and position of cysteine residues of gluten gene plays an important role in flour quality. The reduced number of cysteine residue in Dv-1 may have an impact on the polymer structure of flour,which need to further investigate.Wheat mildew powdery caused by Erysiphe graminis f.sp.Tritici had a great threat to wheat production,largely decrease its quality of flour,development of wheat species with broad spectrum and durable resistance to the numerous physiological races of Erysiphe graminis f.sp.Tritici through genetic engineering is the most economical and efficient method.The barley mlo mutant shows resistance to almost all known isolates of the Erysiphe graminis.Wheat mlo cDNA sequence shows a similarity of 92%to that of barley.So,repression of wheat mlo gene by RNA interfering could result in increased resistance of wheat to powdery mildew.Duo to intron hairpin RNA(ihpRNA) greatly enhance the gene repression efficiency(up to 90%),so we construct the RNAi expression vector pTCK-Cmlo with the 3'end of the wheat mlo cDNA sequence.After transformed into wheat cultivar Yangmai 158,T₀ plants are screened and analyzed. The results show that the positive lines show a greatly increased resistance to Erysiphe graminis f.sp.Tritici.