Molecular marker development and linkage analysis in three low phytic acid barley (Hordeum vulgare) mutant lines

Phytate is the primary form of phosphorus found in mature cereal grain. This form of phosphorus is not available to monogastric animals due to a lack of the enzyme phytase in their digestive tract. Several barley lowphyticacid (lpa) mutants have been identified that contain substantial decreases in seed phytate accompanied by concomitant increases in inorganic phosphorus. Seed homozygous for low phytic acid1-1 (lpa1-1) or low phytic acid2-1 (lpa2-1) has a 50% and 70% decrease in seed phytate respectively. These mutations were previously mapped to chromosomes 2HL and 7HL respectively. The RFLP marker ABC153 located in the same region of 2H was converted to a sequence-characterized-amplified-region (SCAR) marker. Segregation analysis of the CDC McGwire × Lp422 doubled haploid population confirmed linkage between the SCAR marker and the lpa1-1 locus with 15% recombination. A third low phytic acid mutant, M635, has a 75% decrease in phytate. This mutation was located to chromosome 1HL by linkage with an inter-simple sequence repeat (ISSR) based marker (LP75) identified through bulked-segregant analysis, and has been designated lpa3-1. Based on analysis of recombination between marker LP75 and low phytic acid in an additional mutant line M955 (95% phytate decrease), lpa3-1 and the mutation in M955 are in the same region on chromosome 1HL, and may be allelic.