Identification of two Low-Phytate Barley (Hordeum Vulgare l.) Grain Mutants by TLC and Genetic Analysis

Rasmussen, Søren K.; Hatzack, Frank

doi:10.1111/j.1601-5223.1998.00107.x

Cited by 103 publications

(59 citation statements)

References 15 publications

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“…Such mutants, producing seeds in which the chemistry of seed P, but not the total amount of P, is greatly altered, have indeed been isolated in maize (up to 65% reduction in grain phytic-acid content), barley (up to 75% reduction), rice (up to 45% reduction) and soybean (Raboy and Gerbasi 1996;Larson et al 1998Larson et al , 2000Rasmussen and Hatzack 1998;Sebastian et al 2000).…”

Section: Introductionmentioning

confidence: 95%

Phenotypic, genetic and molecular characterization of a maize low phytic acid mutant (lpa241)

et al. 2003

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Phytic acid, myo-inositol 1,2,3,4,5,6-hexakisphosphate, is the major storage compound of phosphorous (P) in plants, predominantly accumulating in seeds (up to 4-5% of dry weight) and pollen. In cereals, phytic acid is deposited in embryo and aleurone grain tissues as a mixed "phytate" salt of potassium and magnesium, although phytates contain other mineral cations such as iron and zinc. During germination, phytates are broken down by the action of phytases, releasing their P, minerals and myo-inositol which become available to the growing seedling. Phytic acid represents an anti-nutritional factor for animals, and isolation of maize low phytic acid ( lpa) mutants provides a novel approach to study its biochemical pathway and to tackle the nutritional problems associated with it. Following chemical mutagenesis of pollen, we have isolated a viable recessive mutant named lpa 241 showing about 90% reduction of phytic acid and about a tenfold increase in seed-free phosphate content. Although germination rate was decreased by about 30% compared to wild-type, developement of mutant plants was apparentely unaffected. The results of the genetic, biochemical and molecular characterization experiments carried out by SSR mapping, MDD-HPLC and RT-PCR are consistent with a mutation affecting the MIPS1S gene, coding for the first enzyme of the phytic acid biosynthetic pathway.

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Section: Introductionmentioning

confidence: 95%

Phenotypic, genetic and molecular characterization of a maize low phytic acid mutant (lpa241)

et al. 2003

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“…Low-phytic acid grain and legume in feed could reduce phosphorus pollution to environment and reduce amount of phosphorus supplementation required in animal feeds (Ertl et al, 1998). Such grain would also offer more available Fe and Zn for human nutrition (Mendoza et al, 1998).Low-phytic acid mutants have been generated by mutagenesis in maize, rice, barley, and soybean (Rasmussen and Hatzack, 1998;Larson et al, 2000;Raboy et al, 2000;Wilcox et al, 2000) and used in genetic breeding (Raboy et al, 2001). Two types of recessive mutants affecting seed phytic acid are known.…”

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confidence: 99%

“…Low-phytic acid mutants have been generated by mutagenesis in maize, rice, barley, and soybean (Rasmussen and Hatzack, 1998;Larson et al, 2000;Raboy et al, 2000;Wilcox et al, 2000) and used in genetic breeding (Raboy et al, 2001). Two types of recessive mutants affecting seed phytic acid are known.…”

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The Maize Low-Phytic Acid Mutant lpa2 Is Caused by Mutation in an Inositol Phosphate Kinase Gene

et al. 2003

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Reduced phytic acid content in seeds is a desired goal for genetic improvement in several crops. Low-phytic acid mutants have been used in genetic breeding, but it is not known what genes are responsible for the low-phytic acid phenotype. Using a reverse genetics approach, we found that the maize (Zea mays) low-phytic acid lpa2 mutant is caused by mutation in an inositol phosphate kinase gene. The maize inositol phosphate kinase (ZmIpk) gene was identified through sequence comparison with human and Arabidopsis Ins(1,3,4)P 3 5/6-kinase genes. The purified recombinant ZmIpk protein has kinase activity on several inositol polyphosphates, including Ins(1,3,4)P 3 , Ins(3,5,6)P 3 , Ins(3,4,5,6)P 4 , and Ins(1,2,5,6)P 4 . The ZmIpk mRNA is expressed in the embryo, the organ where phytic acid accumulates in maize seeds. The ZmIpk Mutator insertion mutants were identified from a Mutator F 2 family. In the ZmIpk Mu insertion mutants, seed phytic acid content is reduced approximately 30%, and inorganic phosphate is increased about 3-fold. The mutants also accumulate myo-inositol and inositol phosphates as in the lpa2 mutant. Allelic tests showed that the ZmIpk Mu insertion mutants are allelic to the lpa2. Southern-blot analysis, cloning, and sequencing of the ZmIpk gene from lpa2 revealed that the lpa2-1 allele is caused by the genomic sequence rearrangement in the ZmIpk locus and the lpa2-2 allele has a nucleotide mutation that generated a stop codon in the N-terminal region of the ZmIpk open reading frame. These results provide evidence that ZmIpk is one of the kinases responsible for phytic acid biosynthesis in developing maize seeds.Phytic acid, myo-inositol 1,2,3,4,5,6-hexakisphosphate, is an abundant component of plant seeds and is deposited in protein bodies as a mixed salt of mineral cations, such as K ϩ , Mg 2ϩ , Ca 2ϩ , Zn 2ϩ , and Fe 3ϩ . Typically, 50% to 80% of the phosphorus in seeds is found in this compound. Phytic acid serves as a major storage form for myo-inositol, phosphorus, and mineral cations for use during seedling growth. The other known role of phytic acid is the control of inorganic phosphate (Pi) levels in both developing seeds and seedlings (Strother, 1980). In maize (Zea mays) kernels, nearly 90% of the phytic acid is accumulated in embryo and about 10% in aleurone layers. Maize endosperm contains only trace amount of phytic acid (O'Dell et al., 1972). In rice (Oryza sativa), barley (Hordeum vulgare), and wheat (Triticum aestivum), most of the phytic acid (approximately 90%) is found in the aleurone layers and only about 10% in embryo. Reduced phytic acid content in seeds is a desired goal for genetic improvement in several crops, including maize, rice, barley, wheat, and soybean (Glycine max). Because monogastric animals digest phytic acid poorly, animal feed is supplemented with Pi to meet the phosphorus requirement for animal growth. Undigested phytic acid is eliminated and is a leading phosphorus pollution source (Cromwell and Coffey, 1991). Although phytic acid as an antioxidant is sugges...

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“…To address these problems, various crops, for example, rice (Oryza sativa L.; Larson et al 2000), maize (Zea mays L.; Raboy et al 2000), barley (Hordeum vulgare L.; Larson et al 1998;Rasmussen and Hatzack 1998), and wheat (Triticum aestivum L.; Guttieri et al 2004), have been developed with lower contents of phytate. For the soybean, a low-phytate mutant has been produced by mutation breeding through chemical mutagenesis (Wilcox et al 2000).…”

Section: Introductionmentioning

confidence: 99%

Growth characteristics, phytate contents, and coagulation properties of soymilk from a low-phytate Japanese soybean (Glycine max(L.) Merr.) line

Fukuda

Tatsukawa

Saneoka

et al. 2011

Soil Science and Plant Nutrition

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The phytic acid (myo-inositol hexakisphosphate or InsP 6 ) content of seed crops is important to their nutritional quality. Since it represents 75 AE 10% of the total seed phosphorus (P), phytic acid is also important regarding the management of P in agricultural production. A low-phytate F5 line, No. T-2-250-4-20, was selected from the progeny of a cross between the low-phytate soybean line CX1834 and the Japanese commercial cultivar Tanbakuro. This line and its parents were grown in a field nursery, and the growth characteristics, phytate accumulation, and processing suitability for tofu were evaluated. At full maturity, the weight of seeds per plant of line T-2-250-4-20 was 5.2-and 1.3-fold higher than that of CX1834 and Tanbakuro, respectively. The amount of phytate-phosphorus as a percentage of the total P content in seeds was 23% in line T-2-250-4-20-34, 30% in CX1834, and 69% in Tanbakuro. No significant difference was observed among the three cultivars/lines in their seed magnesium (Mg), potassium (K), crude protein, and sugar. However, the calcium (Ca), crude fat and ash contents in seeds of line T-2-250-4-20-34 and Tanbakuro was lowered compared to that of CX1834. The breaking stress of tofu was estimated employing a rheometer with a decreasing concentration of the coagulant magnesium chloride (MgCl 2 ), starting at 15.7 mmol L À1. In tofu made from Tanbakuro, the concentration of MgCl 2 required to achieve the maximum breaking stress was 12.6 mmol L À1 ; however, it was 9.5 mmol L À1 for tofu made from T-2-250-4-20-34 and CX1834. The tofu made from Tanbakuro was soft and broke at 6.3 mmol L À1 MgCl 2 , but, in line T-2-250-4-20-34, harder tofu was made with lower MgCl 2 concentrations. No difference was observed among the cultivars/lines in the SDS-PAGE patterns of protein in soymilk. These results indicate that we have developed a low-phytate soybean with adequate productivity, and confirmed that tofu made from the low-phytate T-2-250-4-20-34 soybean becomes coagulated and harder at a lower MgCl 2 concentration than that from high-phytate soybean cultivars.

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Identification of two Low-Phytate Barley (Hordeum Vulgare l.) Grain Mutants by TLC and Genetic Analysis

Cited by 103 publications

References 15 publications

Phenotypic, genetic and molecular characterization of a maize low phytic acid mutant (lpa241)

Phenotypic, genetic and molecular characterization of a maize low phytic acid mutant (lpa241)

The Maize Low-Phytic Acid Mutant lpa2 Is Caused by Mutation in an Inositol Phosphate Kinase Gene

Growth characteristics, phytate contents, and coagulation properties of soymilk from a low-phytate Japanese soybean (Glycine max(L.) Merr.) line

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