Starch branching enzyme

Abstract

This invention relates to a new starch branching enzyme, and to the gene encoding the enzyme. In particular, the invention provides a new starch branching enzyme type II from wheat, the nucleic acid encoding the enzyme, and constructs comprising the nucleic acid. The invention also relates to a novel method for identification of branching enzyme type II proteins, which is useful for screening wheat germplasm for null or altered alleles of wheat branching enzyme IIb. The novel gene, protein and methods of the invention are useful in production of plants which produce grain with novel properties for food and industrial applications, for example wheat grain containing high amylose or low amylopectin starch.

1 - 52 . (canceled) 
     
     
         53 . Wheat grain comprising a null allele of a gene on a long arm of chromosome 2 encoding wheat starch branching enzyme IIb (BEIIb), in combination with one or more null alleles of genes which encode starch branching enzyme IIa (BEIIa), granule bound starch synthase (GBSS), starch synthase II (SSII), or starch branching enzyme I (BEI). 
     
     
         54 . The wheat grain of  claim 53 , wherein the gene encoding BEIIb is a wSBEII gene on a long arm of chromosome 2D. 
     
     
         55 . The wheat grain of  claim 53 , wherein the gene encoding BEIIb corresponds to the partial BEIIb gene present on λ phage clone G5, wherein a sample of G5 has been deposited with the Australian Government Analytical Laboratories under Accession No. NM01/19255. 
     
     
         56 . The wheat grain of  claim 54 , wherein the wSBEII gene comprises introns of the following sizes: intron 1, 148 base pairs; intron 2, 663 base pairs; intron 3, 465 base pairs; intron 4, 74 base pairs; intron 5, 181 base pairs; intron 6, 442 base pairs; intron 7, 79 base pairs; and intron 8, 178 base pairs. 
     
     
         57 . The wheat grain of  claim 53 , wherein the gene encoding BEIIb encodes an RNA corresponding to a cDNA having a nucleotide sequence as set forth in SEQ ID NO: 6. 
     
     
         58 . The wheat grain of  claim 53 , further comprising a null allele of a second gene encoding BEIIb. 
     
     
         59 . The wheat grain of  claim 53 , wherein the grain of the plant comprises an altered amylose-to-amylopectin ratio. 
     
     
         60 . The wheat grain of  claim 54 , further comprising a null allele of a second gene encoding BEIIb. 
     
     
         61 . The wheat grain of  claim 53 , comprising more than one null alleles of genes which encodes BEIIa. 
     
     
         62 . The wheat grain of  claim 53 , which is whole grain. 
     
     
         63 . Wheat flour comprising a null allele of a gene on a long arm of chromosome 2 encoding wheat starch branching enzyme IIb (BEIIb), in combination with one or more null alleles of genes which encode starch branching enzyme IIa (BEIIa), granule bound starch synthase (GBSS), starch synthase II (SSII), or starch branching enzyme I (BEI). 
     
     
         64 . A food product comprising wheat grain or wheat flour, wherein the wheat grain or wheat flour comprises a null allele of a gene on a long arm of chromosome 2 encoding wheat starch branching enzyme IIb (BEIIb), in combination with one or more null alleles of genes which encode starch branching enzyme IIa (BEIIa), granule bound starch synthase (GBSS), starch synthase II (SSII), or starch branching enzyme I (BEI). 
     
     
         65 . The food product of  claim 64 , which is selected from the group consisting of breads, pasta, noodles, breakfast cereals, snack foods, cakes, pastries, foods containing flour and starch-based sauces. 
     
     
         66 . A process of preparing a food product, comprising
 (i) obtaining wheat grain or wheat flour, wherein the wheat grain or wheat flour comprises a null allele of a gene on a long arm of chromosome 2 encoding wheat starch branching enzyme IIb (BEIIb), in combination with one or more null alleles of genes which encode starch branching enzyme IIa (BEIIa), granule bound starch synthase (GBSS), starch synthase II (SSII), or starch branching enzyme I (BEI), and   (ii) processing the wheat grain or wheat flour to prepare the food product.   
     
     
         67 . The process of  claim 66 , wherein the food product is selected from the group consisting of breads, pasta, noodles, breakfast cereals, snack foods, cakes, pastries, foods containing flour and starch-based sauces. 
     
     
         68 . A process of preparing a product, comprising (i) obtaining wheat grain or wheat flour, wherein the wheat grain or wheat flour comprises a null allele of a gene on a long arm of chromosome 2 encoding wheat starch branching enzyme IIb (BEIIb), in combination with one or more null alleles of genes which encode starch branching enzyme IIa (BEIIa), granule bound starch synthase (GBSS), starch synthase II (SSII), or starch branching enzyme I (BEI),
 (ii) isolating starch from the wheat grain or wheat flour, and   (iii) preparing the product from the starch.   
     
     
         69 . The process of  claim 68 , wherein the product is a food product. 
     
     
         70 . The process of  claim 69 , wherein the food product is selected from the group consisting of breads, pasta, noodles, breakfast cereals, snack foods, cakes, pastries, foods containing flour and starch-based sauces. 
     
     
         71 . The process of  claim 68 , wherein the product is a non-food product. 
     
     
         72 . The process of  claim 71 , wherein the non-food product is selected from the group consisting of films, coatings, adhesives, building materials, disposable goods and packaging materials.