Identification and Characterization of a Low Phytic Acid Wheat

Abstract

Phytic acid ( myo ‐inositol‐1,2,3,4,5,6‐hexa kis phosphate, or Ins P 6 ) is the most abundant storage form of P in seeds, yet indigestible by humans and nonruminant livestock. A wheat ( Triticum aestivum L.) mutant is described herein with greatly reduced seed phytic acid P but little change in seed total P, similar to lpa 1‐type mutants described in other grain species. One nonlethal mutant from 562 ethyl‐methanesulfonate (EMS) mutagenized M 2 lines was identified with a high inorganic phosphate (HIP) phenotype 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 74.7% of seed total P in nonmutant or wild‐type control, Js‐12‐WT. 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 four‐fold. Inheritance data of F 2 and F 4:6 families was inconsistent with a single‐gene mutation and suggests the involvement of two or more genes. This low phytic acid wheat mutant is a genetic resource for studying the biology of seed phytic acid metabolism and wheat quality improvement.