Glutenin genes and their uses

#The present invention relates generally to plant molecular biology. In particular, it relates to nucleic acids and methods for improving glutenin content of plants.

#The glutenins, which include both high molecular weight (HMW) glutenin subunits and low molecular weight (LMW) glutenin subunits, comprise an economically important class of wheat seed storage proteins. The apparent molecular weights of the individual HMW glutenin polypeptides or subunits range from 90 to 200 kDa. These subunits crosslink by disulfide bonds among themselves and with LMW glutenin polypeptides to form polymers exceeding one million daltons in molecular weight. HMW glutenins constitute 8-10%, while LMW glutenins constitute 15-20% of the total endosperm protein. Both HMW and LMW glutenin proteins play important functional roles in determining the end-uses of wheat flour.

#In wheat, HMW glutenins are encoded at the Glu-1 loci on the long arms of the group 1 chromosomes. Each locus consists of two separate genes, encoding an x-type and a y-type subunit, respectively. These pairs have never been confirmed to be separated by recombination. This has made determination of their separate contributions to bread dough properties difficult to assess by genetic correlation studies. For a review of the genetics and biochemistry of glutenin polypeptides, see, Shewry et al., J. Cereal Sci. 15:105-120 (1992).

#FIG. 1 is a diagram showing the domains of y-type and x-type HMW glutenins. The C- and N-terminal domains are shaded, the locations of cysteine residues are designated by S.

#FIG. 2A is a diagram showing the structure of a hybrid glutenin polypeptide of the invention.

#FIG. 2B is a diagram of the recombinant plasmid of the invention which encodes the polypeptide shown in FIG. 2A.

#This invention relates to plant glutenin genes, in particular wheat glutenin genes. Nucleic acid sequences from glutenin genes can be used to modify glutenin content in transgenic plants, in particular wheat plants. In addition, the invention provides new seed-specific promoters useful for directing expression of desired genes in a number of plants.

#Generally, the nomenclature and the laboratory procedures in recombinant DNA technology described below are those well known and commonly employed in the art. Standard techniques are used for cloning, DNA and RNA isolation, amplification and purification. Generally enzymatic reactions involving DNA ligase, DNA polymerase, restriction endonucleases and the like are performed according to the manufacturer's specifications. These techniques and various other techniques are generally performed according to Sambrook et al., Molecular Cloning—A Laboratory Manual, Cold Spring Harbor Laboratory, Cold Spring Harbor, N.Y., (1989).

#Glutenin Polypeptides and Genes