Physicochemical properties of low-phytate rice cultivar, Sang-gol

Li, Chunying; He, Lingbing; Choi, Jee Woong; Kim, Hee-Woong; Hong, Soon‐Kwan; Xu, Zhihao; Rhee, Hae-Ik

doi:10.1007/s13765-012-0017-0

Cited by 3 publications

(3 citation statements)

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“…The kinase domain of Lpa1 shows weak homology with that of 2-phosphoglycerate kinase (2-PGK) found in hyperthermophilic methanogens [ 22 ]. However, there is structural similarity among the substrates and products of 2-PGK and Lpa1 [ 45 ].…”

Section: Resultsmentioning

confidence: 99%

Novel allelic variant of Lpa1 gene associated with a significant reduction in seed phytic acid content in rice (Oryza sativa L.)

Kishor

Lee

et al. 2019

PLoS ONE

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In plants, myo-inositol-1,2,3,4,5,6-hexakisphosphate (InsP6), also known as phytic acid (PA), is a major component of organic phosphorus (P), and accounts for up to 85% of the total P in seeds. In rice (Oryza sativa L.), PA mainly accumulates in rice bran, and chelates mineral cations, resulting in mineral deficiencies among brown rice consumers. Therefore, considerable efforts have been focused on the development of low PA (LPA) rice cultivars. In this study, we performed genetic and molecular analyses of OsLpa1, a major PA biosynthesis gene, in Sanggol, a low PA mutant variety developed via chemical mutagenesis of Ilpum rice cultivar. Genetic segregation and sequencing analyses revealed that a recessive allele, lpa1-3, at the OsLpa1 locus (Os02g0819400) was responsible for a significant reduction in seed PA content in Sanggol. The lpa1-3 gene harboured a point mutation (C623T) in the fourth exon of the predicted coding region, resulting in threonine (Thr) to isoleucine (Ile) amino acidsubstitution at position 208 (Thr208Ile). Three-dimensional analysis of Lpa1 protein structure indicated that myo-inositol 3-monophosphate [Ins(3)P1] could bind to the active site of Lpa1, with ATP as a cofactor for catalysis. Furthermore, the presence of Thr208 in the loop adjacent to the entry site of the binding pocket suggests that Thr208Ile substitution is involved in regulating enzyme activity via phosphorylation. Therefore, we propose that Thr208Ile substitution in lpa1-3 reduces Lpa1 enzyme activity in Sanggol, resulting in reduced PA biosynthesis.

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Section: Resultsmentioning

confidence: 99%

Novel allelic variant of Lpa1 gene associated with a significant reduction in seed phytic acid content in rice (Oryza sativa L.)

Kishor

Lee

et al. 2019

PLoS ONE

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“…In rice, molecular characterization of genes encoding MIPS, MIK, Lpa1, ITPK5/6, and IPK1 has revealed association with the low PA phenotype Understanding the genetic basis of low PA phenotype is important for developing cultivars with low PA content in seeds. Therefore, we obtained the low PA mutant cultivar 'Sanggol' from Kangwon National University, Republic of Korea [31,46]. In this study,…”

Section: Biocomputational Analysismentioning

confidence: 99%

“…The kinase domain of Lpa1 shows weak homology with that of 2phosphoglycerate kinase (2-PGK) found in hyperthermophilic methanogens[22]. However, there is structural similarity among the substrates and products of 2-PGK and Lpa1[46].Phylogenetic analysis revealed a strong relationship among the kinase proteins in the glycolysis and PA biosynthesis pathways. This suggests that Lpa proteins encoding Ins(3)P 1 kinase are classified into the Lpa clade (Fig 6B).…”

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confidence: 99%

Novel allelic variant of Lpa1 gene associated with a significant reduction in seed phytic acid content in rice (Oryza sativa L.)

Kishor

Lee

et al. 2018

Preprint

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21In plants, 2,3,4,5, ), also known as phytic acid 22 (PA), is a major component of organic phosphorus (P), and accounts for up to 85% of the total 2 23 P in seeds. In rice (Oryza sativa L.), PA mainly accumulates in rice bran, and chelates mineral 24 cations, resulting in mineral deficiencies among brown rice consumers. Therefore, 25 considerable efforts have been focused on the development of low PA (LPA) rice cultivars. In 26 this study, we performed genetic and molecular analyses of OsLpa1, a major PA biosynthesis 27 gene, in Sanggol, a low PA mutant variety developed via chemical mutagenesis of Ilpum rice 28 cultivar. Genetic segregation and sequencing analyses revealed that a recessive allele, lpa1-3, 29 at the OsLpa1 locus (Os02g0819400) was responsible for a significant reduction in seed PA 30 content in Sanggol. The lpa1-3 gene harboured a point mutation (C623T) in the fourth exon of 31 the predicted coding region, resulting in threonine (Thr) to isoleucine (Ile) amino acid 32 substitution at position 208 (Thr208Ile). Three-dimensional analysis of Lpa1 protein structure 33 indicated that myo-inositol 3-monophosphate [Ins(3)P 1 ] kinase binds to the active site of Lpa1, 34 with ATP as a cofactor for catalysis. Furthermore, the presence of Thr208 in the loop adjacent 35 to the entry site of the binding pocket suggests that Thr208Ile substitution is involved in 36 regulating enzyme activity via phosphorylation. Therefore, we propose that Thr208Ile 37 substitution in lpa1-3 reduces Lpa1 enzyme activity in Sanggol, resulting in reduced PA 38 biosynthesis. 39 40 42 phytic acid (PA), is considered a major source of phosphorus (P) available in the form of 43 phytate, and accounts for 65-85% of the total P in seeds [1]. Monogastric animals poorly digest 44 PA, as they lack the phytase enzyme, which is responsible for the release of phosphate residues 45 [2]. PA is an efficient chelator of mineral cations, such as zinc (Zn 2+ ), iron (Fe 2+ ), magnesium 46 (Mg 2+ ), potassium (K 2+ ), and calcium (Ca 2+ ), in the nutritional tract. Because of these attributes, 3 47 PA is considered as an antinutrient [3, 4]. Hence, there is a need to develop low PA (LPA) crop 48 cultivars to maximize the nutritional benefits of grains. 49 Mutants associated with the LPA phenotype have been identified in several crop plants 50 including maize (Zea mays) [5, 6], barley (Hordeum vulgare) [7], soyabean (Glycine max) [8], 51 rice (Oryza sativa) [9], and wheat (Triticum aestivum) [10]. Although, LPA mutants are 52identified primarily on the basis of percentage reduction of PA and high inorganic P (P i ) content 53 in seeds [5, 11], some mutants show a significant accumulation of myo-inositol and inositol 54 phosphate [Ins(1,3,4)P 3 5-/6] intermediates in seeds [12, 13]. 55Previously, the LPA phenotype of seeds has been associated with reduced agronomic 56 performance of mutant crop plants in the field [5, 14]. It is important to understand the genetic 57 and molecular bases of reduced agronomic performance of LPA mutants for ef...

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Characterization of OsMIK in a rice mutant with reduced phytate content reveals an insertion of a rearranged retrotransposon

Zhao

Hairui

et al. 2013

Theor Appl Genet

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The rice low phytic acid (lpa) mutant Os-lpa-XS110-1(XS-lpa) has ~45 % reduction in seed phytic acid (PA) compared with the wild-type cultivar Xiushui 110. Previously, a single recessive gene mutation was shown to be responsible for the lpa phenotype and was mapped to a region of chromosome 3 near OsMIK (LOC_Os03g52760) and OsIPK1 (LOC_Os03g51610), two genes involved in PA biosynthesis. Here, we report the identification of a large insert in the intron of OsMIK in the XS-lpa mutant. Sequencing of fragments amplified through TAIL-PCRs revealed that the insert was a derivative of the LINE retrotransposon gene LOC_Os03g56910. Further analyses revealed the following characteristics of the insert and its impacts: (1) the inserted sequence of LOC_Os03g56910 was split at its third exon and rejoined inversely, with its 5' and 3' flanking sequences inward and the split third exon segments outward; (2) the LOC_Os03g56910 remained in its original locus in XS-lpa, and the insertion probably resulted from homologous recombination repair of a DNA double strand break; (3) while the OsMIK transcripts of XS-lpa and Xiushui 110 were identical, substantial reductions of the transcript abundance (~87 %) and the protein level (~60 %) were observed in XS-lpa, probably due to increased methylation in its promoter region. The above findings are discussed in the context of plant mutagenesis, epigenetics and lpa breeding.

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Physicochemical properties of low-phytate rice cultivar, Sang-gol

Cited by 3 publications

References 16 publications

Novel allelic variant of Lpa1 gene associated with a significant reduction in seed phytic acid content in rice (Oryza sativa L.)

Novel allelic variant of Lpa1 gene associated with a significant reduction in seed phytic acid content in rice (Oryza sativa L.)

Novel allelic variant of Lpa1 gene associated with a significant reduction in seed phytic acid content in rice (Oryza sativa L.)

Characterization of OsMIK in a rice mutant with reduced phytate content reveals an insertion of a rearranged retrotransposon

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