| Elytrigia possess many important genes or traits for wheat yield and quality improvement. Elytrigia elongata is one of the diploid species belonging to this genus. The HMW glutenin subunits and their structure gene locus on the long arms of IE chromosome (designated as Glu-E1) were confirmed by SDS-PAGE analysis of a set of Chinese spring (1A/1E, IB/IE, 1D/1E).E.elongata substitution lines. Except that, our knowledge about the HMW glutenin in this species was still very limited. In order to get better understanding the HMW glutenin in E. elongata, the HMW glutenin subunits compositions and their coding sequences were analysis and sequenced. The main results were as follows:1. HMW glutenin subunit compositions in Elytrigia elongataTwo to four HMW glutenin subunits could be detected in each of the 8 accessions of E. elongata by SDS-PAGE analysis. To clear the reason why up to four HMW glutenin subunits can be detected in this diploid species, thirty-three different seeds of one accession PI 98526 were further analyzed. Similarly, two to four HMW subunits could still be detected and every grain was different from each other in HMW glutenin subunit compositions. Interestingly, three or four HMW glutenin subunits appeared with the highest frequency of all, indicating that the seeds were heterogeneous and the HMW glutenin were co-expressesed.2. Molecular cloning and sequences analysis of HMW glutenin subunits Ee1.5, Ee1.8, Ee1.9 and Ee2.1Four PCR fragments of the putative HMW glutenin coding regions, ranging from approximately 1.5 to 2.1 kb, were obtained using the genomic DNA from the single plant of PI98526. Four types of positive clones were obtained and selected to represent the complete coding regions of the 1Ex and lEy subunits, respectively. Using a set of subclones prepared by nested deletion, the four HMW glutenin coding sequences, pEel.5, pEel.8, pEel.9 and pEe2.1, were completely sequenced. They have been deposited in the Genbank under accession numbers AY299518, AY298724, AY299520 (pseudogene) and AY299519, respectively.The coding sequence of y type glutenin subunit Ee1.5 had 1492bp in nucleotide and was one of HMW glutenin subunits with the shortest coding regions. In contrast with other y-type HMW glutenin subunits, the N-terminal domain of Eel.5 had 105 but not 104 amino acid residues. Comparison of Eel.5 with Dy10 suggested that Ee1.5 had an extra Cys residue at the middle of repetitive domain, while; the typicalCys residue at the end of repetitive domain in all other y-type HMW glutenin was lost. The coding sequence of another typical y-type HMW glutenin Ee1.8 was made up by 1788bp in nucleotide and could encode a mature protein of 573 amino acid residues.Ee1.9 was a pseudogene and couldn' t encode any mature protein because of an inframe stop code. Ee2.1 was a typical x type HMW glutenin subunit. The coding sequence of Ee2.1 was made up by 2082bp in nucleotide and could encode a mature protein of 670 amino acid residues. An extra Cys residue was found at the central repetitive domain: Another x-type HMW glutenin with an extra Cys residue in repetitive domain was DX5. While, the extra Cys in Dx5 was not at central but at the beginning of repetitive domain, which made Dx5 had better quality score than Dx2 without an extra Cys in this position.It was clear that the coding sequences of HMW glutenin isolated from Elytrigia elongate have novel modification. Such as, an extra amino acid residue was founded in N-terminal and extra Cys was found or lost in repetitive domain and changed in position. All of these changes would endow these HMW glutenin have the potentially better quality scores than those of studied before. So, it was necessary for further understanding the quality functional of these glutenin isolated from E. elongate.3. Phylogenetic relationships of HMW glutenin subunits encoded by A, B and D genome of wheat and by Ee genome of Elytrigia elongataIn the phylogenetic tree made up by N-terminal residues, two x-type subunits Ee1.9 and Ee2.1 were clustered together with Bx7 in high...
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