title: Genome-wide association study of resistant starch (RS) phenotypes in a barley variety collection.
abstract: Barley is primarily grown for feed and malt, but in some regions of the world it is also considered to be a staple food. Some barley types such as high-amylose barley have also gained importance as health-promoting foods. Starch that is not readily digested in the upper mammalian gastrointestinal system, or resistant starch (RS), is considered to be valuable because it prevents some diet-related diseases such as colon cancer. RS was quantified in a diverse collection of 209 spring barley varieties released in Europe during the past 100 years. The RS content varied from <1% to >15% in the collection, with 13 varieties having high RS content (>11%) and 15 varieties below 1%. Combined with genome-wide association scanning (GWAS), SNP markers and candidate genes controlling the RS content in grains were identified. This identified 40 SNP markers with a LOD score above 2, located on chromosomes 2H, 3H, 5H, and 6H, respectively. Among these SNPs, 10 genes with a known role in starch biosynthesis were associated on the basis of synteny conservation to the rice genome. The β-glucan content was quantified in 61 varieties selected to represent extreme as well as medium RS values. The β-glucan amount in the 15 varieties with RS <1% ranged from 1.7 to 3.2%, ranged from 1.76 to 2.54% in the 13 varieties with RS >11%, and ranged from 1.95 to 2.82% for those with 1%< RS < 11%. No statistically significant correlation between RS content and β-glucan content was found. This association analysis of commercial varieties revealed a large variation in RS content and identified a number of SNP markers that can be explored for selection and further dissection of the pathway and control of RS phenotype.
authors.affiliation: Department of Plant and Environmental Sciences, Faculty of Science, Copenhagen University, 1876 Frederiksberg, Copenhagen, Denmark.
authors.forename: Xiaoli
authors.initials: X
authors.lastname: Shu
authors.forename: Gunter
authors.initials: G
authors.lastname: Backes
authors.forename: Søren K
authors.initials: SK
authors.lastname: Rasmussen
mesh_terms: D000688:Amylose / Q000032:analysis; D002874:Chromosome Mapping; D004063:Digestion; D005819:Genetic Markers; D055106:Genome-Wide Association Study; D001467:Hordeum / Q000737:chemistry / Q000235:genetics*; D015810:Linkage Disequilibrium; D008126:Lod Score; D010641:Phenotype; D020641:Polymorphism, Single Nucleotide / Q000235:genetics; D013213:Starch / Q000235:genetics* / Q000378:metabolism*; D047071:beta-Glucans / Q000032:analysis
chemical_list: D005819:Genetic Markers; D047071:beta-Glucans; D013213:Starch; D000688:Amylose