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Kaoru T Yoshida - One of the best experts on this subject based on the ideXlab platform.
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dynamic changes in the distribution of minerals in relation to Phytic Acid accumulation during rice seed development
Plant Physiology, 2012Co-Authors: Toru Iwai, Michiko Takahashi, Koshiro Oda, Yasuko Terada, Kaoru T YoshidaAbstract:Phytic Acid (inositol hexakisphosphate [InsP6]) is the storage compound of phosphorus in seeds. As Phytic Acid binds strongly to metallic cations, it also acts as a storage compound of metals. To understand the mechanisms underlying metal accumulation and localization in relation to Phytic Acid storage, we applied synchrotron-based x-ray microfluorescence imaging analysis to characterize the simultaneous subcellular distribution of some mineral elements (phosphorus, calcium, potassium, iron, zinc, and copper) in immature and mature rice (Oryza sativa) seeds. This fine-imaging method can reveal whether these elements colocalize. We also determined their accumulation patterns and the changes in phosphate and InsP6 contents during seed development. While the InsP6 content in the outer parts of seeds rapidly increased during seed development, the phosphate contents of both the outer and inner parts of seeds remained low. Phosphorus, calcium, potassium, and iron were most abundant in the aleurone layer, and they colocalized throughout seed development. Zinc was broadly distributed from the aleurone layer to the inner endosperm. Copper localized outside the aleurone layer and did not colocalize with phosphorus. From these results, we suggest that phosphorus translocated from source organs was immediately converted to InsP6 and accumulated in aleurone layer cells and that calcium, potassium, and iron accumulated as Phytic Acid salt (phytate) in the aleurone layer, whereas zinc bound loosely to InsP6 and accumulated not only in phytate but also in another storage form. Copper accumulated in the endosperm and may exhibit a storage form other than phytate.
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generation of stable low Phytic Acid transgenic rice through antisense repression of the 1d myo inositol 3 phosphate synthase gene rino1 using the 18 kda oleosin promoter
Plant Biotechnology Journal, 2009Co-Authors: Mio Kuwano, Tetsuro Mimura, Fumio Takaiwa, Kaoru T YoshidaAbstract:Summary Phytic Acid acts as the major storage form of phosphorus in plant seeds and is poorly digested by monogastric animals. The degradation of Phytic Acid in animal diets is necessary to overcome both environmental and nutritional issues. The enzyme 1 D - myo -inositol 3-phosphate [Ins(3)P 1 ] synthase (EC 5.5.1.4) catalyses the first step of myo -inositol biosynthesis and directs Phytic Acid biosynthesis in seeds. The rice Ins(3)P 1 synthase gene ( RINO1 ) is highly expressed in developing seed embryos and in the aleurone layer, where Phytic Acid is synthesized and stored. In rice seeds, 18-kDa oleosin (Ole18) is expressed in a seed-specific manner, and its transcripts are restricted to the embryo and the aleurone layer. Therefore, to effectively suppress Phytic Acid biosynthesis, antisense RINO1 cDNA was expressed under the control of the Ole18 promoter, directing the same spatial pattern in seeds as RINO1 in transgenic rice plants. The generated transgenic rice plants showed strong ‘low Phytic Acid’ (lpa) phenotypes, in which seed Phytic Acid was reduced by 68% and free available phosphate was concomitantly increased. No negative effects on seed weight, germination or plant growth were observed. The available phosphate levels of the stable transgenic plants surpassed those of currently available rice lpa mutants.
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molecular breeding of low Phytic Acid grains in rice by using the promoter of 18 kda oleosin
2007Co-Authors: Mio Kuwano, Fumio Takaiwa, Makoto Suzuki, Kaoru T YoshidaAbstract:In most plant seeds, phosphorus is stored primarily as myo-inositol 1,2,3,4,5,6-hexakisphosphate (InsP6; Phytic Acid). Monogastric animals are unable to utilize Phytic Acid phosphorus efficiently because they lack the digestive enzyme phytase, which is required to cleave phosphorus from Phytic Acid. Mineral phosphate is commonly added to animal diets as a supplement to prevent phosphorus deficiency. This causes high phosphorus concentrations in waste matter, and leads to the pollution of water bodies. Reducing the Phytic Acid content of seeds is a major breeding target, because it would both increase the availability of mineral nutrients and decrease the environmental phosphorus load.
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molecular breeding for transgenic rice with low Phytic Acid phenotype through manipulating myo inositol 3 phosphate synthase gene
Molecular Breeding, 2006Co-Authors: Mio Kuwano, Tetsuro Mimura, Fumio Takaiwa, Akio Ohyama, Yusuke Tanaka, Kaoru T YoshidaAbstract:In most plant seeds, phosphorus is stored primarily as myo-inositol 1,2,3,4,5,6-hexakisphosphate (InsP6; Phytic Acid). Reducing the Phytic Acid content of seeds is a major breeding target, both to increase the availability of mineral nutrients and to decrease the environmental load of phosphorus. The first step in Phytic Acid biosynthesis and inositol metabolism is catalyzed by 1d-myo-inositol 3-phosphate (Ins(3)P1) synthase. In this study, we aimed to reduce Phytic Acid levels in rice seeds by manipulating the expression of the rice Ins(3)P1 synthase gene RINO1 using transgenic methods. RINO1 cDNA was transformed into rice plants in the antisense orientation under the control of the rice major storage protein glutelin GluB-1 promoter. The T4 generation of a stable transgenic line that contained four copies of the transgene showed little morphological differences compared to non-transgenic rice. In the T5 seeds of this line, severe reductions in RINO1 protein levels were observed during the late maturing stages of ripening. Most of the T5 seeds contained higher amounts of inorganic phosphates (Pi), without a reduction in total phosphorus levels, compared to non-transgenic seeds. Ion chromatography analysis suggested that the increase in available Pi is accompanied by a molar-equivalent decrease in Phytic Acid P. The expression patterns of RINO1 and GluB-1 were examined by quantitative real-time reverse transcriptase-polymerase chain-reaction (RT-PCR). Potential strategies for further molecular breeding to reduce Phytic Acid levels in seeds are discussed.
David S Ertl - One of the best experts on this subject based on the ideXlab platform.
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embryo specific silencing of a transporter reduces Phytic Acid content of maize and soybean seeds
Nature Biotechnology, 2007Co-Authors: Jinrui Shi, David S Ertl, Robert B Meeley, Hongyu Wang, Kathleen Schellin, Marianna Faller, Johan M Stoop, Jerry Ranch, Kimberly GlassmanAbstract:Phytic Acid in cereal grains and oilseeds is poorly digested by monogastric animals and negatively affects animal nutrition and the environment. However, breeding programs involving mutants with less Phytic Acid and more inorganic phosphate (Pi) have been frustrated by undesirable agronomic characteristics associated with the Phytic Acid-reducing mutations. We show that maize lpa1 mutants are defective in a multidrug resistance-associated protein (MRP) ATP-binding cassette (ABC) transporter that is expressed most highly in embryos, but also in immature endosperm, germinating seed and vegetative tissues. Silencing expression of this transporter in an embryo-specific manner produced low-Phytic-Acid, high-Pi transgenic maize seeds that germinate normally and do not show any significant reduction in seed dry weight. This dominant transgenic approach obviates the need for incorporating recessive lpa1 mutations to create maize hybrids with reduced Phytic Acid. Suppressing the homologous soybean MRP gene also generated low-Phytic-Acid seed, suggesting that the strategy might be feasible for many crops.
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the maize low Phytic Acid 3 encodes a myo inositol kinase that plays a role in Phytic Acid biosynthesis in developing seeds
Plant Journal, 2005Co-Authors: Jinrui Shi, David S Ertl, Jan Hazebroek, Hongyu Wang, Teresa HarpAbstract:*Summary Phytic Acid, myo-inositol-1,2,3,4,5,6-hexakis phosphate or Ins P 6, is the most abundant myo-inositol phosphate in plant cells, but its biosynthesis is poorly understood. Also uncertain is the role of myo-inositol as a precursor of Phytic Acid biosynthesis. We identified a low-Phytic Acid mutant, lpa3, in maize. The Mu-insertion mutant has a phenotype of reduced Phytic Acid, increased myo-inositol and lacks significant amounts of myo-inositol phosphate intermediates in seeds. The gene responsible for the mutation encodes a myo-inositol kinase (MIK). Maize MIK protein contains conserved amino Acid residues found in pfkB carbohydrate kinases. The maize lpa3 gene is expressed in developing embryos, where Phytic Acid is actively synthesized and accumulates to a large amount. Characterization of the lpa3 mutant provides direct evidence for the role of myo-inositol and MIK in Phytic Acid biosynthesis in developing seeds. Recombinant maize MIK phosphorylates myo-inositol to produce multiple myo-inositol monophosphates, Ins(1/3)P, Ins(4/6)P and possibly Ins(5)P. The characteristics of the lpa3 mutant and MIK suggest that MIK is not a salvage enzyme for myo-inositol recycling and that there are multiple phosphorylation routes to Phytic Acid in developing seeds. Analysis of the lpa2/lpa3 double mutant implies interactions between the phosphorylation routes.
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the maize low Phytic Acid mutant lpa2 is caused by mutation in an inositol phosphate kinase gene
Plant Physiology, 2003Co-Authors: Hongyu Wang, Yunsheng Wu, Jan Hazebroek, Robert B Meeley, David S ErtlAbstract: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.
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origin and seed phenotype of maize low Phytic Acid 1 1 and low Phytic Acid 2 1
Plant Physiology, 2000Co-Authors: Victor Raboy, Kevin A Young, Paola F Gerbasi, Sierra D Stoneberg, Suewiya G Pickett, Andrew T Bauman, Pushpalatha P N Murthy, William F Sheridan, David S ErtlAbstract:Phytic Acid (myo-inositol-1, 2, 3, 4, 5, 6-hexakisphosphate or Ins P(6)) typically represents approximately 75% to 80% of maize (Zea mays) seed total P. Here we describe the origin, inheritance, and seed phenotype of two non-lethal maize low Phytic Acid mutants, lpa1-1 and lpa2-1. The loci map to two sites on chromosome 1S. Seed Phytic Acid P is reduced in these mutants by 50% to 66% but seed total P is unaltered. The decrease in Phytic Acid P in mature lpa1-1 seeds is accompanied by a corresponding increase in inorganic phosphate (P(i)). In mature lpa2-1 seed it is accompanied by increases in P(i) and at least three other myo-inositol (Ins) phosphates (and/or their respective enantiomers): D-Ins(1,2,4,5,6) P(5); D-Ins (1,4,5,6) P(4); and D-Ins(1,2,6) P(3). In both cases the sum of seed P(i) and Ins phosphates (including Phytic Acid) is constant and similar to that observed in normal seeds. In both mutants P chemistry appears to be perturbed throughout seed development. Homozygosity for either mutant results in a seed dry weight loss, ranging from 4% to 23%. These results indicate that Phytic Acid metabolism during seed development is not solely responsible for P homeostasis and indicate that the Phytic Acid concentration typical of a normal maize seed is not essential to seed function.
Mio Kuwano - One of the best experts on this subject based on the ideXlab platform.
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generation of stable low Phytic Acid transgenic rice through antisense repression of the 1d myo inositol 3 phosphate synthase gene rino1 using the 18 kda oleosin promoter
Plant Biotechnology Journal, 2009Co-Authors: Mio Kuwano, Tetsuro Mimura, Fumio Takaiwa, Kaoru T YoshidaAbstract:Summary Phytic Acid acts as the major storage form of phosphorus in plant seeds and is poorly digested by monogastric animals. The degradation of Phytic Acid in animal diets is necessary to overcome both environmental and nutritional issues. The enzyme 1 D - myo -inositol 3-phosphate [Ins(3)P 1 ] synthase (EC 5.5.1.4) catalyses the first step of myo -inositol biosynthesis and directs Phytic Acid biosynthesis in seeds. The rice Ins(3)P 1 synthase gene ( RINO1 ) is highly expressed in developing seed embryos and in the aleurone layer, where Phytic Acid is synthesized and stored. In rice seeds, 18-kDa oleosin (Ole18) is expressed in a seed-specific manner, and its transcripts are restricted to the embryo and the aleurone layer. Therefore, to effectively suppress Phytic Acid biosynthesis, antisense RINO1 cDNA was expressed under the control of the Ole18 promoter, directing the same spatial pattern in seeds as RINO1 in transgenic rice plants. The generated transgenic rice plants showed strong ‘low Phytic Acid’ (lpa) phenotypes, in which seed Phytic Acid was reduced by 68% and free available phosphate was concomitantly increased. No negative effects on seed weight, germination or plant growth were observed. The available phosphate levels of the stable transgenic plants surpassed those of currently available rice lpa mutants.
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molecular breeding of low Phytic Acid grains in rice by using the promoter of 18 kda oleosin
2007Co-Authors: Mio Kuwano, Fumio Takaiwa, Makoto Suzuki, Kaoru T YoshidaAbstract:In most plant seeds, phosphorus is stored primarily as myo-inositol 1,2,3,4,5,6-hexakisphosphate (InsP6; Phytic Acid). Monogastric animals are unable to utilize Phytic Acid phosphorus efficiently because they lack the digestive enzyme phytase, which is required to cleave phosphorus from Phytic Acid. Mineral phosphate is commonly added to animal diets as a supplement to prevent phosphorus deficiency. This causes high phosphorus concentrations in waste matter, and leads to the pollution of water bodies. Reducing the Phytic Acid content of seeds is a major breeding target, because it would both increase the availability of mineral nutrients and decrease the environmental phosphorus load.
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molecular breeding for transgenic rice with low Phytic Acid phenotype through manipulating myo inositol 3 phosphate synthase gene
Molecular Breeding, 2006Co-Authors: Mio Kuwano, Tetsuro Mimura, Fumio Takaiwa, Akio Ohyama, Yusuke Tanaka, Kaoru T YoshidaAbstract:In most plant seeds, phosphorus is stored primarily as myo-inositol 1,2,3,4,5,6-hexakisphosphate (InsP6; Phytic Acid). Reducing the Phytic Acid content of seeds is a major breeding target, both to increase the availability of mineral nutrients and to decrease the environmental load of phosphorus. The first step in Phytic Acid biosynthesis and inositol metabolism is catalyzed by 1d-myo-inositol 3-phosphate (Ins(3)P1) synthase. In this study, we aimed to reduce Phytic Acid levels in rice seeds by manipulating the expression of the rice Ins(3)P1 synthase gene RINO1 using transgenic methods. RINO1 cDNA was transformed into rice plants in the antisense orientation under the control of the rice major storage protein glutelin GluB-1 promoter. The T4 generation of a stable transgenic line that contained four copies of the transgene showed little morphological differences compared to non-transgenic rice. In the T5 seeds of this line, severe reductions in RINO1 protein levels were observed during the late maturing stages of ripening. Most of the T5 seeds contained higher amounts of inorganic phosphates (Pi), without a reduction in total phosphorus levels, compared to non-transgenic seeds. Ion chromatography analysis suggested that the increase in available Pi is accompanied by a molar-equivalent decrease in Phytic Acid P. The expression patterns of RINO1 and GluB-1 were examined by quantitative real-time reverse transcriptase-polymerase chain-reaction (RT-PCR). Potential strategies for further molecular breeding to reduce Phytic Acid levels in seeds are discussed.
Fuhui Wang - One of the best experts on this subject based on the ideXlab platform.
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influence of substrate composition on the formation of Phytic Acid conversion coatings
Materials and Corrosion-werkstoffe Und Korrosion, 2012Co-Authors: Xiufang Cui, Guo Jin, Fuhui Wang, Erbao Liu, M H DingAbstract:In this paper, the formation and corrosion resistance of the Phytic Acid conversion coatings on Mg, Al, and AZ91D magnesium alloy were contrastively investigated using scanning electronic microscopy (SEM), Auger electron spectroscopy (AES), Fourier transform infrared spectroscopy (FTIR), electronic probe microscopic analyzer (EPMA), electronic balance, and electrochemical methods. The influence of Phytic Acid conversion coating as a middle layer on the properties of the paint on magnesium alloys was also investigated.
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electroless ni p plating with a Phytic Acid pretreatment on az91d magnesium alloy
Materials Chemistry and Physics, 2010Co-Authors: Xiufang Cui, Guo Jin, Yuyun Yang, Fuhui WangAbstract:A Phytic Acid conversion film with especial functional groups was proposed as the pretreatment layer between Ni-P coating and AZ91D magnesium alloy substrate, to replace the traditional pretreatment. In the process, the silane coupling agent was adopted as connector between conversion film and palladium ion with catalysis. The microstructure of the Phytic Acid conversion coatings was observed using scanning electronic microscopy, while the composition and functional groups were analyzed by energy dispersive spectrometer and Fourier transform infrared spectroscopy. The bonding between Si-OH of the silane coupling agent and hydroxyl of Phytic Acid was validated by X-ray photoelectron spectroscopy, and the existence of palladium ion was also verified. The subsequent Ni-P deposited on the layer was also characterized by its structure, morphology, and corrosion resistance. The results show that the Ni-P coatings with the Phytic Acid pretreatment on AZ91D magnesium alloy have good corrosion resistance. (C) 2010 Elsevier B.V. All rights reserved.
Victor Raboy - One of the best experts on this subject based on the ideXlab platform.
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identification and characterization of a low Phytic Acid wheat
Crop Science, 2004Co-Authors: Mary J Guttieri, Victor Raboy, David Bowen, John Dorsch, Edward SouzaAbstract:Phytic Acid (myo-inositol-1,2,3,4,5,6-hexakisphosphate, 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 add P but little change in seed total P, similar to Ipal-type mutants described in other grain species. One nonlethal mutant from 562 ethyl-methanesulfonate (EMS) mutageniied 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.
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genetics and breeding of seed phosphorus and Phytic Acid
Journal of Plant Physiology, 2001Co-Authors: Victor Raboy, Kevin A Young, John A Dorsch, Allen CookAbstract:Summary The isolation of cereallow Phytic Acid (lpa) mutants provides a novel approach to studying the biology of seed Phytic Acid (myo-inositol-1,2,3,4,5,6-hexakisphosphate or Ins P6), and to dealing with environmental and nutritional problems associated with it. Seed produced bylpa lines contain normal levels of total phosphorus (P), but greatly reduced levels of Phytic Acid P. Two phenotypically distinct types oflpa mutants have been isolated in maize (Zea mays L.), barley (Hordeum vulgare L.), and rice (Oryza sativa L.). In «lpa1-like» mutants, seed Phytic Acid P reductions ranging from 50 percnt; to 95 percnt; (in comparison with levels typical of non-mutant seed) are largely matched by corresponding increases in inorganic P. In «lpa2-like» mutants, seed Phytic Acid P reductions ranging from 50 percnt; to 75 percnt; are matched by increases in both inorganic P and inmyo-inositol (Ins) phosphates containing five or fewer P esters (compared with Phytic Acid's six P esters). In all cases the sum of seed Ins phosphates (including Phytic Acid) and inorganic P remains constant and similar to that in normal seeds. Somelpa alleles are lethal as homozygotes, others have a negative effect on plant or seed growth and function but are viable, still others have little effect and are being used to breed «low phytate» maize and barley types. Progress inlpa genetics and breeding, and the animal and human nutrition studies conducted with these new crop types, will be reviewed.
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low Phytic Acid grains
Food and Nutrition Bulletin, 2000Co-Authors: Victor RaboyAbstract:As one approach to the improvement of the nutritional quality of crops for both foods and feeds, low-Phytic-Acid (lpa) mutants of maize and other cereals have been isolated. An important advantage ...
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isolation and genetic mapping of a non lethal rice oryza sativa l low Phytic Acid 1 mutation
Crop Science, 2000Co-Authors: Steve R. Larson, Neil J Rutger, Kevin A Young, Victor RaboyAbstract:Phytic Acid (myo-inositol 1,2,3,4,5,6 hexakisphosphate) is the most abundant form of phosphorus (P) in seeds and is virtually indigestible by humans or non-ruminant livestock. It was hypothesized that one class of maize (Zea mays L.) and barley (Hordeum vulgare L.) low Phytic Acid mutations, designated Ipal, interrupt myo-inositol supply during seed development and may be mutations of the myo-inositol 1-phosphate synthase (MIPS) gene. This study describes the isolation, inheritance, and genetic mapping of the first rice Ipal mutation and reexamines the MIPS/lpa1 candidate gene hypothesis in rice. Grain from 3632 rice M2 lines, derived from gamma-irradiated seed, was screened for the Ipa phenotype. Two mutations, one lethal and one non-lethal, were identified. The non-lethal mutation is phenotypically similar to maize and barley lpa1 mutants and was designated rice lpa1-1. Homozygosity for rice lpa1-1 reduces the Phytic Acid portion of seed P from 71 to 39% and increases the inorganic portion of seed P from 5 to 32%, with little effect on total seed P. This rice lpa1 mutation was mapped to a 2.2-cM interval on chromosome 2L. A single-copy rice MIPS gene was mapped to a locus on rice chromosome 3 that is orthologous to MIPS loci on maize chromosome IS (near maize Ipal ) and barley chromosome 4H. Unlike maize Ipal, the rice and barley lpa1 mutations loci are dearly distinguishable from this canonical MIPS gene. No relationship can be inferred between the maize, barley, and rice Ipal loci. Although this canonical MIPS gene may be an appropriate target for controlling seed Phytic Acid synthesis, modifications of other genes (e.g., maize lpa2, barley lpa1, barley lpa2, and rice Ipal ) may also be useful in reducing grain Phytic Acid and improving the nutritional value of cereal grains and/or milling hy-products.
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origin and seed phenotype of maize low Phytic Acid 1 1 and low Phytic Acid 2 1
Plant Physiology, 2000Co-Authors: Victor Raboy, Kevin A Young, Paola F Gerbasi, Sierra D Stoneberg, Suewiya G Pickett, Andrew T Bauman, Pushpalatha P N Murthy, William F Sheridan, David S ErtlAbstract:Phytic Acid (myo-inositol-1, 2, 3, 4, 5, 6-hexakisphosphate or Ins P(6)) typically represents approximately 75% to 80% of maize (Zea mays) seed total P. Here we describe the origin, inheritance, and seed phenotype of two non-lethal maize low Phytic Acid mutants, lpa1-1 and lpa2-1. The loci map to two sites on chromosome 1S. Seed Phytic Acid P is reduced in these mutants by 50% to 66% but seed total P is unaltered. The decrease in Phytic Acid P in mature lpa1-1 seeds is accompanied by a corresponding increase in inorganic phosphate (P(i)). In mature lpa2-1 seed it is accompanied by increases in P(i) and at least three other myo-inositol (Ins) phosphates (and/or their respective enantiomers): D-Ins(1,2,4,5,6) P(5); D-Ins (1,4,5,6) P(4); and D-Ins(1,2,6) P(3). In both cases the sum of seed P(i) and Ins phosphates (including Phytic Acid) is constant and similar to that observed in normal seeds. In both mutants P chemistry appears to be perturbed throughout seed development. Homozygosity for either mutant results in a seed dry weight loss, ranging from 4% to 23%. These results indicate that Phytic Acid metabolism during seed development is not solely responsible for P homeostasis and indicate that the Phytic Acid concentration typical of a normal maize seed is not essential to seed function.