Identification and Characterization of a Low Phytic Acid Wheat

Abstract

Phytic acid (myo‐inositol‐1,2,3,4,5,6‐hexakisphosphate, or Ins P6) 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 lpa1‐type mutants described in other grain species. One nonlethal mutant from 562 ethyl‐methanesulfonate (EMS) mutagenized M2 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 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 is a genetic resource for studying the biology of seed phytic acid metabolism and wheat quality improvement.

Nutritionally Enhanced Staple Food Crops

“…Studies of germplasm collections have revealed significant genetic variation for both seed phytate and/or total P in common bean, lentil, sorghum, soybean, and wheat (Lolas and Markakis 1975;Raboy et al 1991;Israel et al 2006;Kayode et al 2006;Ficco et al 2009;Thavarajah et al 2010;Akond et al 2011). Likewise, researchers have used both chemical and physical mutagens to isolate lp mutants in barley (Raboy 2000;Bowen et al 2006), common bean (Campion et al 2009), maize (Raboy 2000;Badone et al 2010), rice (Larson et al 2000;Raboy 2000;Rutger et al 2004;Liu et al 2007;Kim et al 2008), soybean (Wilcox et al 2000;Walker et al 2006), and wheat (Guttieri et al 2004). These studies reported two types of mutants, those with moderate reduction (50%-65%) or extreme reduction (95%) in phytic acid, with the latter being homozygotes and lethal.…”

Wheat breeding for low phytic acid content: State and perspectives

“…Fitinska kiselina kao polivalentni anjon stvara helate sa mineralnim elementima i proteinima, onemogućavajući njihovo potpuno iskorišćavanje. Ishrana bogata fitinskom kiselinom značajno smanjuje apsorpciju važnih mikronutrijenata (kalcijum, cink, gvožđe, mangan i bakar) koje ljudi i nepreživari (živina, svinje, ribe) u vidu mešovitih soli izlučuju, dovodeći do njihovog ozbiljnog defi cita, naročito kod siromašnih i zemalja u razvoju (Reicwald & Hatzack 2008, Khan et al 2007, Guttieri et al 2004, Lönnerdal 2002, García-Estepa et al 1999, Tabekhia & Donelly 1982, Nahapetian & Bassiri 1976, Lolas et al 1976.…”

“…Obuhvata jedan do nekoliko procenata suve mase semena i 50% do 85% ukupnog fosfora u semenu pšenice (Raboy 2001a, Guttieri et al 2004, Hídvégi & Lásztity 2002, Khan et al 2007, Yenagi & Basarkar 2007, Dintzis et al 1992, Nahapetian & Basiri 1976. Količina fosfora sintetisana u formi InsP 6 predstavlja više od 50% unešenog fosfora u agroekosisteme mineralnim đubrenjem na godišnjem nivou.…”

“…Insignia da se fi tinska kiselina nalazi u klici, skutelumu, aleuronskom omotaču i spoljašnjim frakcijama perikarpa, dok se ne nalazi u frakcijama endosperma (Guttieri et al 2004, Hídvégi & Lásztity 2002, Febles et al 2001, Williams 1970. Fitinska kiselina se akumulira u aleuronu pšeničnog zrna koje je prošlo normalan tok razvoja posle 28 dana od početka klijanja, i posle 23 dana od početka klijanja kod zrna izloženog stresnim uslovima.…”

“…Dobijen je mutant pšenice (Triticum aestivum L.) niskog sadržaja fi tinske kiseline i označen je kao Js-12-LPA (Guttieri et al 2004). Js-12-LPA homozigoti imaju zrna u kojima je fosfor fi tinske kiseline predstavljen sa 48,2% ukupnog fosfora zrna u poređenju sa nemutantnim (wild type WT) genotipom Js-12-WT, kod koga je sadržaj fi tatnog fosfora u odnosu na ukupni 74,7%.…”