Submitted to: Molecular Breeding
Publication Type: Peer reviewed journal
Publication Acceptance Date: 3/12/2007
Publication Date: 5/8/2007
Citation: Roslinsky, V., Eckstein, P.E., Rossnagel, B.G., Scoles, G.J., Raboy, V. 2007. Molecular Marker Development and Linkage Analysis in Three Low Phytic Acid Barley (Hordeum vulgare) Mutant Lines. Molecular Breeding. Interpretive Summary: Development of low-phytate crops is desirable since it will improve the nutritional value of grains when used in monogastric animal feeds and also possibly when used in human foods. One tool that will be very helpful in breeding low-phytate crops will be molecular markers linked to low phytic acid genes. Barley is an important crop and up till the present molecular markers have been identified that are linked to two barley low phytic acid genes referred to as barley low phytic acid 1 and barley low phytic acid 2. Molecular markers have now been identified that are linked to a third barley low phytic acid gene, low phytic acid 3-1. This molecular marker adds another valuable tool to the tool box useful in rapid breeding and development of high-yielding low-phytate crops.
Technical Abstract: 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 low phytic acid (lpa) mutants have been identified that contain substantial decreases in seed phytate accompanied by concomitant increases in inorganic phosphorus. Seed homozygous for low phytic acid 1-1 (lpa1-1) or low phytic acid 2-1 (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 x lpa1-1 doubled haploid population confirmed linkage between the SCAR marker and the lpa1-1 locus with 15 % recombination. A third low-phytate mutant, M635, has a 75 % decrease in phytate. This mutation was mapped to chromosome 1HL by linkage with an ISSR-based marker (LP75) developed through bulked-segregant analysis, and has been designated lpa3-1. Based on an analysis of recombination between molecular marker LP75 and low-phytic acid in M955 (95 % phytate decrease), lpa3-1 and the mutation in M955 are in the same region on chromosome 1HL, and may be allelic.