Development of high amylose wheat through TILLING

• Published in: BMC plant biology Vol. 12; no. 1; p. 69
• Main Authors: Slade, Ann J, McGuire, Cate, Loeffler, Dayna, Mullenberg, Jessica, Skinner, Wayne, Fazio, Gia, Holm, Aaron, Brandt, Kali M, Steine, Michael N, Goodstal, John F, Knauf, Vic C
• Format: Journal Article
• Language: English
• Published: England BioMed Central Ltd 14.05.2012; BioMed Central; BMC
• Subjects: 1,4-alpha-Glucan Branching Enzyme - genetics; 1,4-alpha-Glucan Branching Enzyme - metabolism; Alleles; Amino Acid Substitution; Amylose; Amylose - analysis; Amylose - genetics; Amylose - metabolism; Biological diversity; Breeding; Carbohydrates; DNA, Plant - genetics; Endosperm - chemistry; Endosperm - enzymology; Endosperm - genetics; Enzymes; Gene expression; Gene Expression Regulation, Plant - genetics; Genes; Genetic diversity; Genetic engineering; Genome, Plant - genetics; Genomes; Genomics; Genotype; Health aspects; Molecular Sequence Data; Mutation; Obesity; Peptides; Phenotype; Physiological aspects; Plant Leaves - chemistry; Plant Leaves - enzymology; Plant Leaves - genetics; Plant Proteins - genetics; Plant Proteins - metabolism; Polymorphism, Single Nucleotide - genetics; Polyploidy; Product development; Protein Isoforms - genetics; Proteins; RNA, Plant - genetics; Sequence Analysis, DNA; Single nucleotide polymorphisms; Software; Starch - chemistry; Starch - genetics; Starch - metabolism; Triticum - chemistry; Triticum - enzymology; Triticum - genetics; Wheat; United States
• ISSN: 1471-2229; 1471-2229
• DOI: 10.1186/1471-2229-12-69

Wheat (Triticum spp.) is an important source of food worldwide and the focus of considerable efforts to identify new combinations of genetic diversity for crop improvement. In particular, wheat starch composition is a major target for changes that could benefit human health. Starches with increased levels of amylose are of interest because of the correlation between higher amylose content and elevated levels of resistant starch, which has been shown to have beneficial effects on health for combating obesity and diabetes. TILLING (Targeting Induced Local Lesions in Genomes) is a means to identify novel genetic variation without the need for direct selection of phenotypes. Using TILLING to identify novel genetic variation in each of the A and B genomes in tetraploid durum wheat and the A, B and D genomes in hexaploid bread wheat, we have identified mutations in the form of single nucleotide polymorphisms (SNPs) in starch branching enzyme IIa genes (SBEIIa). Combining these new alleles of SBEIIa through breeding resulted in the development of high amylose durum and bread wheat varieties containing 47-55% amylose and having elevated resistant starch levels compared to wild-type wheat. High amylose lines also had reduced expression of SBEIIa RNA, changes in starch granule morphology and altered starch granule protein profiles as evaluated by mass spectrometry. We report the use of TILLING to develop new traits in crops with complex genomes without the use of transgenic modifications. Combined mutations in SBEIIa in durum and bread wheat varieties resulted in lines with significantly increased amylose and resistant starch contents.