Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/1/2003
Publication Date: 3/1/2004
Citation: Guttieri, M., Bowen, D., Dorsch, J.A., Raboy, V., Souza, E. 2004. Identification and characterization of a low phytic acid wheat. Crop Science 44:418-424. Interpretive Summary: Interpretive Summary: Phytic acid is the storage form of phosphorus in seeds. It is not readily digestible by non-ruminant livestock such as poultry, swine and fish, nor by humans. This can cause significant problems in the management of phosphorus in livestock production, and in human nutrition and health. One approach to studying the nutritional impact of phytic acid in feed and food, and to studying the biology of phytic acid in plants and seeds, is to isolate 'low phytic acid' mutants. This report described the isolation of the first low phytic acid mutant of wheat. This mutant, termed 'JS-12-LPA', was found to produce seed with about a 35% reduction in phytic acid, as compared with normal seed. The isolation of this first wheat low phytic acid mutation also represents a first step in developing and breeding Low Phytate wheats.
Technical Abstract: Phytic acid (myo-inositol-1,2,3,4,5,6-hexakisphosphate) is the most abundant storage form of phosphorus (P) in seeds and is virtually indigestible by humans and non-ruminant livestock. A class of low phytic acid maize (Zea mays L.), barley (Hordeum vulgare L.), rice (Oryza sativa L.) and soybean [Glycine max (L.) Merr.] mutants, designated lpa1, have been described. Seed produced by mutants of this phenotypic class have greatly reduced seed phytic acid P, but little change in seed total P. The reduction in phytic acid P is matched by an increase in seed inorganic P. A wheat (Triticum aestivum L.) lpa1-like mutant is described. Grain from 562 M2 lines, derived from EMS-mutagenized wheat, was screened for the high inorganic phosphate (HIP) phenotype of lpa seeds. One non-lethal mutant was identified and designated Js-12-LPA. Js-12-LPA homozygotes produced seed in which phytic acid P represented 48.2% of seed total P, in contrast to seed produced by the non-mutant or "wild-type" control, Js-12-WT, in which phytic acid P represents 74.7% of seed total P. The inorganic portion of seed P was increased from 9.1% in Js-12-WT to 50.1% in Js-12-LPA, with little effect on total seed P. Weight distributions among milling fractions were similar for the Js-12-LPA and Js-12-WT genotypes. The low phytic acid trait altered the distribution of total P within the kernel, increasing the P content of the central endosperm and decreasing the P content of the bran. The low phytic acid trait decreased the phytic acid concentration in the bran by 43% and increased the inorganic P concentration in the bran nearly 4-fold. Inheritance data of F2 and F4:6 families was inconsistent with a single-gene mutation and suggests the involvement of two or more genes. This low phytic acid wheat mutant adds to the genetic resources of value in studying the biology of seed phytic acid metabolism, and of value in studies addressing wheat quality improvement.