Identification of quantitative trait locus (QTLs) for γ-aminobutyric acid content in grain of barley

Abstract

r-Aminobutyric acid (GABA) has not only some physiological functions in plants and animals, but also has been used extensively in pharmaceuticals and functional foods for human health. To realize its genetic basis, in this study, a 192 plants F₂ population derived from the cross between Ziguang manluoerling (ZGMLEL) and Schooner was used for quantitative trait locus (QTL) mapping for GABA content in grain for barley (Hordeum vulgare L.). As a result, four QTLs (qGABA3-1, qGABA4-1, qGABA4-2, and qGABA4-3) were identified on chromosomes 3 and 4, of which these QTLs could explain phenotypic variance from 8.02 to 24.50%, due to additive effects for qGABA3-1 and qGABA4-1 from ZGMLEL on chromosome 3 and 4. Meanwhile, part dominance effects for qGABA4-2 and qGABA4- 3 from ZGMLEL on chromosome 4, especially the marker interval (GBM1299-GBM1482) of qGABA4-2 accounting for 24.50% of the phenotypic variance. To our knowledge, these are the first QTLs to be identified controlling GABA content in grains of barley. These results are beneficial for understanding the genetic basis of GABA and developing the markers linked with GABA for marker-assisted selection breeding in barley.

Key words: γ-Aminobutyric acid (GABA), quantitative trait locus (QTL), grain, barley.