Molecular Cloning And Sequences Analysis Of Low Molecular Weight Glutenin Gene Coding Regions From T.aestevum Ssp.tibetanum Shao

The types and numbers of the low molecular weight glutenin (LMW glutenin) subunits have a profound influence on the end-use quality of wheat flours. Isolated LMW glutenin sequences from T.aestivwn,T.durum, T.boeoticutn,T.momococum and Ae.tauschii all revealed that the coding sequence of these genes were moderate in length and conserved in the composition of nucleotide and no intron inframe. All of these characters led to the possibility of isolation these genes by PCR strategies. Tibetan Semi-wild wheat (T.aestevum ssp.tibetanum Shao) is one of the special germplasms which native to China and have the potentially value in the study of wheat origin and classification. In the work reported in this thesis, we isolated and sequenced three coding sequences of LMW glutenin from Tibetan Semi-wild wheat (T.aestevum ssp.tibetanum Shao) AS908. The main results were as follows:1. Amplified LMW glutenin coding sequences from Tibetan Semi-wild wheat (T,aestevum ssp.tibetanum Shao) AS908 by primers of Glu-D3 locus encoded glutenin was about 950bp in length. This length was nearly equal to the coding sequences of LMW glutenin from other sources.2. Three LMW glutenin sequences (named to Tibet 1,Tibet2 and Tibet 3) were obtained after positive clone screen and sequencing. These sequences were despotized in Genbank under accession numbers AY299457 , AY299458 and AY299459, respectively. Among them, the coding sequences of Tibet1 and Tibet2 were 1041bp and 906bp and could encoding two mature proteins including 326 and 281 amino acid residues, respectively. The coding sequences of Tibet3 could not encode any mature proteins because of two inframe stop codens.3. Multiple sequences alignment suggested that three isolated sequences are homologous of wheat LMW glutenin. It can be predicated that Tibetl is encode by Glu-D3 locus and the encoding locus of Tibet2 and Tibet3 is not clear.4. Sequences between AY299457 and AY214450 and between AY299458 andAJ293099 were very similar in primary structures and amino acids compositions suggested that both pairs might have the very similar quality functions to wheat flours.