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da Rocha Rodrigues R, Caseli L, Péres LO. Langmuir and Langmuir-Blodgett Films of Poly[(9,9-dioctylfluorene)- co-(3-hexylthiophene)] for Immobilization of Phytase: Possible Application as a Phytic Acid Sensor. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:10587-10596. [PMID: 32786889 DOI: 10.1021/acs.langmuir.0c01941] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
In this work, the copolymer poly[(9,9-dioctylfluorene)-co-(3-hexylthiophene)] was employed as a matrix for immobilizing phytase, aiming at the detection of phytic acid. The copolymer was spread on the air-water interface forming Langmuir monolayers and phytase adsorbed from the aqueous subphase. The interactions between the copolymer and the enzyme components were investigated with surface pressure and surface potential-area isotherms, Brewster angle microscopy, and polarization modulation infrared reflection-absorption spectroscopy (PM-IRRAS). The enzyme could be incorporated in the monolayers from the aqueous subphase, expanding the copolymer films and maintaining its secondary structure. The polymeric films presented a morphological heterogeneous pattern at the air-water interface because of the ability of their chains to fold and entangle, causing inherent defects in the organization as well as unbalanced lateral distribution at the air-water interface because of the formation of aggregates. The interfacial films were transferred to solid supports as Langmuir-Blodgett films and characterized by PM-IRRAS and scanning electronic microscopy, which showed not only the co-transfer of the enzyme but also the maintenance of their heterogeneous morphological pattern. The enzymatic activity of the blended film was analyzed by UV-vis spectroscopy and allowed the estimation of the value of the Michaelis constant (13.08 mM), demonstrating the feasibility of the system to selectively detect phytic acid for biosensing purposes.
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Affiliation(s)
- Rebeca da Rocha Rodrigues
- Laboratory of Hybrid Materials, Department of Chemistry, Federal University of Sao Paulo (UNIFESP), 210 São Nicolau Street, Diadema, São Paulo, Brazil
| | - Luciano Caseli
- Laboratory of Hybrid Materials, Department of Chemistry, Federal University of Sao Paulo (UNIFESP), 210 São Nicolau Street, Diadema, São Paulo, Brazil
| | - Laura Oliveira Péres
- Laboratory of Hybrid Materials, Department of Chemistry, Federal University of Sao Paulo (UNIFESP), 210 São Nicolau Street, Diadema, São Paulo, Brazil
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Pandey V, Krishnan V, Basak N, Marathe A, Thimmegowda V, Dahuja A, Jolly M, Sachdev A. Molecular modeling and in silico characterization of GmABCC5: a phytate transporter and potential target for low-phytate crops. 3 Biotech 2018; 8:54. [PMID: 29354365 DOI: 10.1007/s13205-017-1053-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Accepted: 12/17/2017] [Indexed: 02/06/2023] Open
Abstract
Designing low-phytate crops without affecting the developmental process in plants had led to the identification of ABCC5 gene in soybean. The GmABCC5 gene was identified and a partial gene sequence was cloned from popular Indian soybean genotype Pusa16. Conserved domains and motifs unique to ABC transporters were identified in the 30 homologous sequences retrieved by BLASTP analysis. The homologs were analyzed for their evolutionary relationship and physiochemical properties. Conserved domains, transmembrane architecture and secondary structure of GmABCC5 were predicted with the aid of computational tools. Analysis identified 53 alpha helices and 31 beta strands, predicting 60% residues in alpha conformation. A three-dimensional (3D) model for GmABCC5 was developed based on 5twv.1.B (Homo sapiens) template homology to gain better insight into its molecular mechanism of transport and sequestration. Spatio-temporal real-time PCR analysis identified mid-to-late seed developmental stages as the time window for the maximum GmABCC5 gene expression, a potential target stage for phytate reduction. Results of this study provide valuable insights into the structural and functional characteristics of GmABCC5, which may be further utilized for the development of nutritionally enriched low-phytate soybean with improved mineral bioavailability.
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Affiliation(s)
- Vanita Pandey
- 1Division of Biochemistry, ICAR-Indian Agricultural Research Institute, New Delhi, 110012 India
- Quality and Basic Sciences, ICAR-Indian Institute of Wheat and Barley Research, Karnal, New Delhi 132 001 India
| | - Veda Krishnan
- 1Division of Biochemistry, ICAR-Indian Agricultural Research Institute, New Delhi, 110012 India
| | - Nabaneeta Basak
- 1Division of Biochemistry, ICAR-Indian Agricultural Research Institute, New Delhi, 110012 India
- Crop Physiology and Biochemistry, ICAR-National Rice Research Institute, Cuttack, 753006 India
| | - Ashish Marathe
- 1Division of Biochemistry, ICAR-Indian Agricultural Research Institute, New Delhi, 110012 India
| | - Vinutha Thimmegowda
- 1Division of Biochemistry, ICAR-Indian Agricultural Research Institute, New Delhi, 110012 India
| | - Anil Dahuja
- 1Division of Biochemistry, ICAR-Indian Agricultural Research Institute, New Delhi, 110012 India
| | - Monica Jolly
- 1Division of Biochemistry, ICAR-Indian Agricultural Research Institute, New Delhi, 110012 India
| | - Archana Sachdev
- 1Division of Biochemistry, ICAR-Indian Agricultural Research Institute, New Delhi, 110012 India
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Berga F, Rodriguez A, Costa-Bauzá A, Grases F. Novel Colorimetric Determination of Phytate in Urine. ANAL LETT 2015. [DOI: 10.1080/00032719.2015.1060599] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Ahmad A, Niwa Y, Goto S, Kobayashi K, Shimizu M, Ito S, Usui Y, Nakayama T, Kobayashi H. Genome-wide screening of salt tolerant genes by activation-tagging using dedifferentiated calli of Arabidopsis and its application to finding gene for Myo-inositol-1-p-synthase. PLoS One 2015; 10:e0115502. [PMID: 25978457 PMCID: PMC4433338 DOI: 10.1371/journal.pone.0115502] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Accepted: 11/23/2014] [Indexed: 11/19/2022] Open
Abstract
Salinity represents a major abiotic stress factor that can adversely limit the production, quality and geographical distribution of crops. In this study we focused on dedifferentiated calli with fundamental cell functions, the salt tolerance of which had not been previously examined. The experimental approach was based on activation tagging without regeneration of plants for the identification of salt-tolerant mutants of Arabidopsis. Among 62,000 transformed calli that were screened, 18 potential mutants resistant to 150 mM NaCl were obtained. Thermal asymmetric interlaced (TAIL)-PCR was performed to determine the location of T-DNA integration in the genome. In one line, referred to as salt tolerant callus 1 (stc1), expression of a gene [At4g39800: myo-inositol-1-P-synthase 1 (MIPS1)] was considerably enhanced in calli. Plants regenerated from calli showed tolerance to salt in germination and subsequent growth. Retransformation of wild-type Arabidopsis with MIPS1 conferred salt tolerance, indicating that MIPS1 is the causal gene. The over-expression of MIPS1 increased the content of total inositol. The involvement of MIPS1 in salt tolerance through the fundamental cell growth has been proved in Arabidopsis.
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Affiliation(s)
- Aftab Ahmad
- Laboratory of Plant Molecular Improvement, Graduate School of Nutritional and Environmental Sciences, University of Shizuoka, 52–1 Yada, Suruga, Shizuoka 422–8526, Japan
| | - Yasuo Niwa
- Laboratory of Plant Molecular Improvement, Graduate School of Nutritional and Environmental Sciences, University of Shizuoka, 52–1 Yada, Suruga, Shizuoka 422–8526, Japan
| | - Shingo Goto
- Laboratory of Plant Molecular Improvement, Graduate School of Nutritional and Environmental Sciences, University of Shizuoka, 52–1 Yada, Suruga, Shizuoka 422–8526, Japan
| | - Kyoko Kobayashi
- Laboratory of Plant Molecular Improvement, Graduate School of Nutritional and Environmental Sciences, University of Shizuoka, 52–1 Yada, Suruga, Shizuoka 422–8526, Japan
| | - Masanori Shimizu
- Laboratory of Plant Molecular Improvement, Graduate School of Nutritional and Environmental Sciences, University of Shizuoka, 52–1 Yada, Suruga, Shizuoka 422–8526, Japan
| | - Sohei Ito
- Laboratory of Protein Engineering, Graduate School of Nutritional and Environmental Sciences, University of Shizuoka, 52–1 Yada, Suruga, Shizuoka 422–8526, Japan
| | - Yumiko Usui
- Laboratory of Molecular Fooineering, Graduate School of Nutritional and Environmental Sciences, University of Shizuoka, 52–1 Yada, Suruga, Shizuoka 422–8526, Japan
| | - Tsutomu Nakayama
- Laboratory of Molecular Fooineering, Graduate School of Nutritional and Environmental Sciences, University of Shizuoka, 52–1 Yada, Suruga, Shizuoka 422–8526, Japan
| | - Hirokazu Kobayashi
- Laboratory of Plant Molecular Improvement, Graduate School of Nutritional and Environmental Sciences, University of Shizuoka, 52–1 Yada, Suruga, Shizuoka 422–8526, Japan
- * E-mail:
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Costa-Bauza A, Grases F, Gomila I, Rodriguez A, Prieto RM, Tur F. A simple and rapid colorimetric method for determination of phytate in urine. ACTA ACUST UNITED AC 2012; 40:663-9. [DOI: 10.1007/s00240-012-0473-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2011] [Accepted: 03/24/2012] [Indexed: 11/24/2022]
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Panzeri D, Cassani E, Doria E, Tagliabue G, Forti L, Campion B, Bollini R, Brearley CA, Pilu R, Nielsen E, Sparvoli F. A defective ABC transporter of the MRP family, responsible for the bean lpa1 mutation, affects the regulation of the phytic acid pathway, reduces seed myo-inositol and alters ABA sensitivity. THE NEW PHYTOLOGIST 2011; 191:70-83. [PMID: 21395595 DOI: 10.1111/j.1469-8137.2011.03666.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
• We previously identified the lpa1 (low phytic acid) 280-10 line that carries a mutation conferring a 90% reduction in phytic acid (InsP(6) ) content. In contrast to other lpa mutants, lpa1(280-10) does not display negative pleiotropic effects. In the present paper, we have identified the mutated gene and analysed its impact on the phytic acid pathway. • Here, we mapped the lpa1(280-10) mutation by bulk analysis on a segregating F(2) population, an then, by comparison with the soybean genome, we identified and sequenced a candidate gene. The InsP(6) pathway was analysed by gene expression and quantification of metabolites. • The mutated Pvmrp1(280-10) cosegregates with the lpa1(280-10) mutation, and the expression level of several genes of the InsP(6) pathway are reduced in the lpa1(280-10) mutant as well as the inositol and raffinosaccharide content. PvMrp2, a very similar paralogue of PvMrp1 was also mapped and sequenced. • The lpa1 mutation in beans is likely the result of a defective Mrp1 gene (orthologous to the lpa genes AtMRP5 and ZmMRP4), while its Mrp2 paralog is not able to complement the mutant phenotype in the seed. This mutation appears to down-regulate the InsP(6) pathway at the transcriptional level, as well as altering inositol-related metabolism and affecting ABA sensitivity.
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Affiliation(s)
- Dario Panzeri
- Istituto di Biologia e Biotecnologia Agraria, CNR, Milano, Italy
| | - Elena Cassani
- Dipartimento di Produzione Vegetale, Università degli Studi di Milano, Italy
| | - Enrico Doria
- Dipartimento di Genetica e Microbiologia, Università di Pavia, Pavia, Italy
| | | | - Luca Forti
- Dipartimento di Chimica, Università di Modena, Modena, Italy
| | - Bruno Campion
- Unità di ricerca per l'Orticoltura CRA, Montanaso Lombardo, Lodi, Italy
| | - Roberto Bollini
- Istituto di Biologia e Biotecnologia Agraria, CNR, Milano, Italy
| | - Charles A Brearley
- School of Biological Sciences, University of East Anglia, Norwich NR4 7TJ, UK
| | - Roberto Pilu
- Dipartimento di Produzione Vegetale, Università degli Studi di Milano, Italy
| | - Erik Nielsen
- Dipartimento di Genetica e Microbiologia, Università di Pavia, Pavia, Italy
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Kvasnička F, Čopíková J, Ševčík R, Václavíková E, Synytsya A, Vaculová K, Voldřich M. Determination of phytic acid and inositolphosphates in barley. Electrophoresis 2011; 32:1090-3. [DOI: 10.1002/elps.201000578] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2010] [Revised: 12/13/2010] [Accepted: 12/13/2010] [Indexed: 11/09/2022]
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8
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Nagy R, Grob H, Weder B, Green P, Klein M, Frelet-Barrand A, Schjoerring JK, Brearley C, Martinoia E. The Arabidopsis ATP-binding cassette protein AtMRP5/AtABCC5 is a high affinity inositol hexakisphosphate transporter involved in guard cell signaling and phytate storage. J Biol Chem 2009; 284:33614-22. [PMID: 19797057 DOI: 10.1074/jbc.m109.030247] [Citation(s) in RCA: 155] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Arabidopsis possesses a superfamily of ATP-binding cassette (ABC) transporters. Among these, the multidrug resistance-associated protein AtMRP5/AtABCC5 regulates stomatal aperture and controls plasma membrane anion channels of guard cells. Remarkably, despite the prominent role of AtMRP5 in conferring partial drought insensitivity upon Arabidopsis, we know little of the biochemical function of AtMRP5. Our phylogenetic analysis showed that AtMRP5 is closely related to maize MRP4, mutation of which confers a low inositol hexakisphosphate kernel phenotype. We now show that insertion mutants of AtMRP5 display a low inositol hexakisphosphate phenotype in seed tissue and that this phenotype is associated with alterations of mineral cation and phosphate status. By heterologous expression in yeast, we demonstrate that AtMRP5 encodes a specific and high affinity ATP-dependent inositol hexakisphosphate transporter that is sensitive to inhibitors of ABC transporters. Moreover, complementation of the mrp5-1 insertion mutants of Arabidopsis with the AtMRP5 cDNA driven from a guard cell-specific promoter restores the sensitivity of the mutant to abscisic acid-mediated inhibition of stomatal opening. Additionally, we show that mutation of residues of the Walker B motif prevents restoring the multiple phenotypes associated with mrp5-1. Our findings highlight a novel function of plant ABC transporters that may be relevant to other kingdoms. They also extend the signaling repertoire of this ubiquitous inositol polyphosphate signaling molecule.
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Affiliation(s)
- Réka Nagy
- University of Zurich, Institute of Plant Biology, Zollikerstrasse 107, CH-8008 Zürich, Switzerland.
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Li CY, Park DS, Won SR, Hong SK, Ham JK, Choi JK, Rhee HI. Food chemical properties of low-phytate rice cultivar, Sang-gol. J Cereal Sci 2008. [DOI: 10.1016/j.jcs.2007.04.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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10
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Suzuki M, Tanaka K, Kuwano M, Yoshida KT. Expression pattern of inositol phosphate-related enzymes in rice (Oryza sativa L.): implications for the phytic acid biosynthetic pathway. Gene 2007; 405:55-64. [PMID: 17961936 DOI: 10.1016/j.gene.2007.09.006] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2007] [Revised: 08/13/2007] [Accepted: 09/06/2007] [Indexed: 11/29/2022]
Abstract
Phytic acid, myo-inositol-hexakisphosphate (InsP(6)), is a storage form of phosphorus in plants. Despite many physiological investigations of phytic acid accumulation and storage, little is known at the molecular level about its biosynthetic pathway in plants. Recent work has suggested two pathways. One is an inositol lipid-independent pathway that occurs through the sequential phosphorylation of 1D-myo-inositol 3-phosphate (Ins(3)P). The second is a phospholipase C (PLC)-mediated pathway, in which inositol 1,4,5-tris-phosphate (Ins(1,4,5)P(3)) is sequentially phosphorylated to InsP(6). We identified 12 genes from rice (Oryza sativa L.) that code for the enzymes that may be involved in the metabolism of inositol phosphates. These enzymes include 1D-myo-inositol 3-phosphate synthase (MIPS), inositol monophosphatase (IMP), inositol 1,4,5-tris-phosphate kinase/inositol polyphosphate kinase (IPK2), inositol 1,3,4,5,6-pentakisphosphate 2-kinase (IPK1), and inositol 1,3,4-triskisphosphate 5/6-kinase (ITP5/6K). The quantification of absolute amounts of mRNA by real-time RT-PCR revealed the unique expression patterns of these genes. Outstanding up-regulation of the four genes, a MIPS, an IPK1, and two ITP5/6Ks in embryos, suggested that they play a significant role in phytic acid biosynthesis and that the lipid-independent pathway was mainly active in developing seeds. On the other hand, the up-regulation of a MIPS, an IMP, an IPK2, and an ITP5/6K in anthers suggested that a PLC-mediated pathway was active in addition to a lipid-independent pathway in the anthers.
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Affiliation(s)
- Makoto Suzuki
- Graduate School of Agricultural and Life Sciences, University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8657, Japan
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Josefsen L, Bohn L, Sørensen MB, Rasmussen SK. Characterization of a multifunctional inositol phosphate kinase from rice and barley belonging to the ATP-grasp superfamily. Gene 2007; 397:114-25. [PMID: 17531407 DOI: 10.1016/j.gene.2007.04.018] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2007] [Revised: 04/04/2007] [Accepted: 04/13/2007] [Indexed: 11/16/2022]
Abstract
OsIpk and HvIpk, inositol phosphate kinases, were cloned from rice (Oryza sativa L. var. indica, IR64) and barley (Hordeum vulgare) respectively. Sequence alignment showed that they belong to the ATP-grasp family, which includes inositol 1,3,4-trisphosphate 5/6-kinase from humans and Arabidopsis. Residues that are binding sites for ATP and coordinate magnesium in absence or presence of inositol phosphate are conserved and in total 23 residues are invariant among the twelve aligned inositol phosphate kinases. The genes were heterologously expressed in Escherichia coli and kinase activity assays with 17 different isomers of inositol mono-/di-/tri-/tetra-/pentaphosphate as well as phytate were performed. The strongest activity for both kinases was observed with Ins(3,4,5,6)P(4), which candidates as the primary substrate for these kinases in plants. Several species-specific differences between the two recombinant Ipks were observed. Rice OsIpk showed detectable kinase activity towards eight different substrates, whereas barley HvIpk showed kinase activity with all the substrates including inositol mono- and bisphosphates. HvIpk showed 3-kinase activity towards the Ins(1,4,5)P(3) substrate and it also interconverted the two substrates Ins(1,3,4,5)P(4) and Ins(1,3,4,6)P(4) by isomerase activity, which was not observed for the rice homologue. Both OsIpk and HvIpk had no detectable 2-kinase activity. Furthermore, the two Ipks showed phosphatase activity towards several inositol phosphates. Expression analysis by RT-PCR demonstrated that the Ipk gene was equally expressed in different tissues and developmental stages. Taken together, these results show that the Ipk kinase plays a significant role in the inositol phosphate interacting network in plants.
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Affiliation(s)
- Lone Josefsen
- Department of Agricultural Sciences, Faculty of Life Science, University of Copenhagen, Frederiksberg C, Denmark
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Nunes ACS, Vianna GR, Cuneo F, Amaya-Farfán J, de Capdeville G, Rech EL, Aragão FJL. RNAi-mediated silencing of the myo-inositol-1-phosphate synthase gene (GmMIPS1) in transgenic soybean inhibited seed development and reduced phytate content. PLANTA 2006; 224:125-32. [PMID: 16395584 DOI: 10.1007/s00425-005-0201-0] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2005] [Accepted: 11/15/2005] [Indexed: 05/06/2023]
Abstract
Inositol plays a role in membrane trafficking and signaling in addition to regulating cellular metabolism and controlling growth. In plants, the myo-inositol-1-phosphate is synthesized from glucose 6-phosphate in a reaction catalyzed by the enzyme myo-inositol-1-phosphate synthase (EC 5.5.1.4). Inositol can be converted into phytic acid (phytate), the most abundant form of phosphate in seeds. The path to phytate has been suggested to proceed via the sequential phosphorylation of inositol phosphates, and/or in part via phosphatidylinositol phosphate. Soybean [Glycine max (L.) Merrill] lines were produced using interfering RNA (RNAi) construct in order to silence the myo-inositol-1-phosphate (GmMIPS1) gene. We have observed an absence of seed development in lines in which the presence of GmMIPS1 transcripts was not detected. In addition, a drastic reduction of phytate (InsP6) content was achieved in transgenic lines (up to 94.5%). Our results demonstrated an important correlation between GmMIPS1 gene expression and seed development.
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Affiliation(s)
- Aline C S Nunes
- Embrapa Recursos Genéticos e Biotecnologia, PqEB W5 Norte, 70770-900 Brasília, DF, Brazil
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Sweetman D, Johnson S, Caddick S, Hanke D, Brearley C. Characterization of an Arabidopsis inositol 1,3,4,5,6-pentakisphosphate 2-kinase (AtIPK1). Biochem J 2006; 394:95-103. [PMID: 16223361 PMCID: PMC1386007 DOI: 10.1042/bj20051331] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The metabolic pathway(s) by which plants synthesize InsP6 (inositol 1,2,3,4,5,6-hexakisphosphate) remains largely undefined [Shears (1998) Biochim. Biophys. Acta 1436, 49-67], while the identities of the genes that encode enzymes catalysing individual steps in these pathways are, with the notable exception of myo-inositol phosphate synthase and ZmIpk [Shi, Wang, Wu, Hazebroek, Meeley and Ertl (2003) Plant Physiol. 131, 507-515], unidentified. A yeast enzyme, ScIPK1, catalyses the synthesis of InsP6 by 2-phosphorylation of Ins(1,3,4,5,6)P5 (inositol 1,3,4,5,6-pentakisphosphate). A human orthologue, HsIPK1, is able to substitute for yeast ScIPK1, restoring InsP6 production in a Saccharomyces cerevisiae mutant strain lacking the ScIPK1 open reading frame (ScIpk1Delta). We have identified an Arabidopsis genomic sequence, AtIPK1, encoding an Ins(1,3,4,5,6)P5 2-kinase. Inclusion of the AtIPK1 protein in alignments of amino acid sequences reveals that human and Arabidopis kinases are more similar to each other than to the S. cerevisiae enzyme, and further identifies an additional motif. Recombinant AtIPK1 protein expressed in Escherichia coli catalysed the synthesis of InsP6 from Ins(1,3,4,5,6)P5. The enzyme obeyed Michaelis-Menten kinetics with an apparent V(max) of 35 nmol x min(-1) x (mg of protein)(-1) and a K(m) for Ins(1,3,4,5,6)P5 of 22 microM at 0.4 mM ATP. RT (reverse transcriptase)-PCR analysis of AtIPK1 transcripts revealed that AtIPK1 is expressed in siliques, leaves and cauline leaves. In situ hybridization experiments further revealed strong expression of AtIPK1 in male and female organs of flower buds. Expression of AtIPK1 protein in an ScIpk1Delta mutant strain restored InsP6 production and rescued the temperature-sensitive growth phenotype of the yeast.
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Affiliation(s)
- Dylan Sweetman
- *School of Biological Sciences, University of East Anglia, Norwich NR4 7TJ, U.K
| | - Sue Johnson
- *School of Biological Sciences, University of East Anglia, Norwich NR4 7TJ, U.K
| | | | - David E. Hanke
- †Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, U.K
| | - Charles A. Brearley
- *School of Biological Sciences, University of East Anglia, Norwich NR4 7TJ, U.K
- To whom correspondence may be addressed (email )
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Lin WH, Wang Y, Mueller-Roeber B, Brearley CA, Xu ZH, Xue HW. At5PTase13 modulates cotyledon vein development through regulating auxin homeostasis. PLANT PHYSIOLOGY 2005; 139:1677-91. [PMID: 16299182 PMCID: PMC1310551 DOI: 10.1104/pp.105.067140] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Phosphatidylinositol signaling pathway and the relevant metabolites are known to be critical to the modulation of different aspects of plant growth, development, and stress responses. Inositol polyphosphate 5-phosphatase is a key enzyme involved in phosphatidylinositol metabolism and is encoded by an At5PTase gene family in Arabidopsis thaliana. A previous study shows that At5PTase11 mediates cotyledon vascular development probably through the regulation of intracellular calcium levels. In this study, we provide evidence that At5PTase13 modulates the development of cotyledon veins through its regulation of auxin homeostasis. A T-DNA insertional knockout mutant, At5pt13-1, showed a defect in development of the cotyledon vein, which was rescued completely by exogenous auxin and in part by brassinolide, a steroid hormone. Furthermore, the mutant had reduced auxin content and altered auxin accumulation in seedlings revealed by the DR5:beta-glucuronidase fusion construct in seedlings. In addition, microarray analysis shows that the transcription of key genes responsible for auxin biosynthesis and transport was altered in At5pt13-1. The At5pt13-1 mutant was also less sensitive to auxin inhibition of root elongation. These results suggest that At5PTase13 regulates the homeostasis of auxin, a key hormone controlling vascular development in plants.
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Affiliation(s)
- Wen-Hui Lin
- National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 200032 Shanghai, People's Republic of China
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Joyce C, Deneau A, Peterson K, Ockenden I, Raboy V, Lott JN. The concentrations and distributions of phytic acid phosphorus and other mineral nutrients in wild-type and low phytic acid Js-12-LPA wheat (Triticum aestivum) grain parts. ACTA ACUST UNITED AC 2005. [DOI: 10.1139/b05-128] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Concentrations of P, phytic acid (myo-inositol hexakisphosphate, IP6), and other mineral storage elements were studied in wild-type and low phytic acid (lpa) genotype Js-12-LPA wheat (Triticum aestivum L.) embryos and rest-of-grain fractions. Environmental scanning electron microscopy images revealed a decreased average size and an increased number of aleurone layer globoids in lpa grains compared with the wild type. Energy-dispersive X-ray analyses of unfixed aleurone layer and scutellum cell cytoplasm revealed mainly C, O, P, K, and Mg in both grain types. The starchy endosperm contained virtually no P, K, or Mg, demonstrating no shift of mineral nutrients to that compartment. Scanning transmission electron microscopy – energy-dispersive X-ray analyses of scutellum and aleurone layer globoids in both genotypes revealed that P, K, and Mg were the main mineral nutrients in globoids with low amounts of Ca, Fe, and Zn. Traces of Mn were only in scutellum globoids. Total P was similar between genotypes for the rest-of-grain fractions, which are 97% of grain mass. The main inositol phosphate was IP6, but a small amount of IP5 was present. Both lpa grain fractions exhibited major reductions in IP6 compared with the wild type and a threefold increase in inorganic P. The concentration of K decreased in both fractions, while Ca increased 25% in the Js-12-LPA rest-of-grain compared with the wild type. The lack of large differences in mineral concentration and distribution between the wild type and Js-12-LPA indicates that there is no direct role of localization of IP6 synthesis in mineral distribution.
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Affiliation(s)
- Charlie Joyce
- Department of Biology, McMaster University, Hamilton, ON L8S 4K1, Canada
- United States Department of Agriculture, Agricultural Research Service, Aberdeen, ID 83210, USA
| | - Andrea Deneau
- Department of Biology, McMaster University, Hamilton, ON L8S 4K1, Canada
- United States Department of Agriculture, Agricultural Research Service, Aberdeen, ID 83210, USA
| | - Kevin Peterson
- Department of Biology, McMaster University, Hamilton, ON L8S 4K1, Canada
- United States Department of Agriculture, Agricultural Research Service, Aberdeen, ID 83210, USA
| | - Irene Ockenden
- Department of Biology, McMaster University, Hamilton, ON L8S 4K1, Canada
- United States Department of Agriculture, Agricultural Research Service, Aberdeen, ID 83210, USA
| | - Victor Raboy
- Department of Biology, McMaster University, Hamilton, ON L8S 4K1, Canada
- United States Department of Agriculture, Agricultural Research Service, Aberdeen, ID 83210, USA
| | - John N.A. Lott
- Department of Biology, McMaster University, Hamilton, ON L8S 4K1, Canada
- United States Department of Agriculture, Agricultural Research Service, Aberdeen, ID 83210, USA
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17
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Abstract
myo-Inositol-1,2,3,4,5,6-hexakisphosphate (Ins P(6)) was first described as an abundant form of phosphorus in plant seeds and other plant tissues and dubbed "phytic acid". Subsequently it was found to be a common constituent in eukaryotic cells, its metabolism a basic component of cellular housekeeping. In addition to phosphate, myo-inositol (Ins) and mineral storage and retrieval in plant organs and tissues, other roles for Ins P(6) include service as a major metabolic pool in Ins phosphate and pyrophosphate pathways involved in signaling and regulation; possibly as an effector or ligand in these processes; as a form of energy currency and in ATP regeneration; in RNA export and DNA repair; and as an anti-oxidant. The relatively recent demonstration that pyrophosphate-containing derivatives of Ins P(6) can function as phosphate donors in the regeneration of ATP is reminiscent of the proposal, made four decades ago in studies of seed development, that Ins P(6) itself may serve in this function. Studies of Ins P(6) in non-plant systems rarely include the consideration that this compound might represent a significant fraction of cellular P; cellular phosphate nutrition has been viewed as either not interesting or of little importance. However, there may be few fundamental differences among diverse eukaryotes in both the metabolic pathways involving Ins P(6) and the spectrum of possible roles for it and its metabolites.
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Affiliation(s)
- Victor Raboy
- USDA-ARS, 1691 South 2700 West, Aberdeen, ID 83210, USA.
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18
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Pilu R, Panzeri D, Gavazzi G, Rasmussen SK, Consonni G, Nielsen E. Phenotypic, genetic and molecular characterization of a maize low phytic acid mutant (lpa241). TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2003; 107:980-7. [PMID: 14523526 DOI: 10.1007/s00122-003-1316-y] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2002] [Accepted: 03/26/2003] [Indexed: 05/10/2023]
Abstract
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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Affiliation(s)
- R Pilu
- Dipartimento di Produzione Vegetale, Università degli Studi di Milano, Via Celoria 2, 20133 Milano, Italy
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19
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Dorsch JA, Cook A, Young KA, Anderson JM, Bauman AT, Volkmann CJ, Murthy PPN, Raboy V. Seed phosphorus and inositol phosphate phenotype of barley low phytic acid genotypes. PHYTOCHEMISTRY 2003; 62:691-706. [PMID: 12620321 DOI: 10.1016/s0031-9422(02)00610-6] [Citation(s) in RCA: 108] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
myo-Inositol-1,2,3,4,5,6-hexakisphosphate (Ins P(6) or "phytic acid") typically represents approximately 75% of the total phosphorus and >80% of soluble myo-inositol (Ins) phosphates in seeds. The seed phosphorus and Ins phosphate phenotypes of four non-lethal barley (Hordeum vulgare L.) low phytic acid mutations are described. In seeds homozygous for M 635 and M 955 reductions in Ins P(6), approximately 75 and >90% respectively, are accompanied by reductions in other Ins phosphates and molar-equivalent increases in Pi. This phenotype suggests a block in supply of substrate Ins. In seeds homozygous for barley low phytic acid 1-1 (lpa1-1), a 45% decrease in Ins P(6) is mostly matched by an increase in Pi but also accompanied by small increases in Ins(1,2,3,4,6)P(5). In seeds homozygous for barley lpa2-1, reductions in seed Ins P(6) are accompanied by increases in both Pi and in several Ins phosphates, a phenotype that suggests a lesion in Ins phosphate metabolism, rather than Ins supply. The increased Ins phosphates in barley lpa2-1 seed are: Ins(1,2,3,4,6)P(5); Ins(1,2,4,6)P(4) and/or its enantiomer Ins(2,3,4,6)P(4); Ins(1,2,3,4)P(4) and/or its enantiomer Ins(1,2,3,6)P(4); Ins(1,2,6)P(3) and/or its enantiomer Ins(2,3,4)P(3); Ins(1,5,6)P(3) and/or its enantiomer Ins(3,4,5)P(3) (the methods used here cannot distinguish between enantiomers). This primarily "5-OH" series of Ins phosphates differs from the "1-/3-OH" series observed at elevated levels in seed of the maize lpa2 genotype, but previous chromosomal mapping data indicated that the maize and barley lpa2 loci might be orthologs of a single ancestral gene. Therefore one hypothesis that might explain the differing lpa2 phenotypes is that their common ancestral gene encodes a multi-functional, Ins phosphate kinase with both "1-/-3-" and "5-kinase" activities. A putative pyrophosphate-containing Ins phosphate, possibly an Ins P(7), was also observed in the mature seed of all barley genotypes except lpa2-1. Barley M 955 indicates that at least for this species, the ability to accumulate Ins P(6) can be nearly abolished while retaining at least short-term ( approximately 1.0 years) viability.
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Affiliation(s)
- John A Dorsch
- USDA-ARS, 1691 South 2700 West, Aberdeen, ID 83210, USA
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20
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Affiliation(s)
- Brian Q Phillippy
- United States Department of Agriculture, Agricultural Research Service, Southern Regional Research Center, New Orleans, LA 70124, USA
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21
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Shi J, Wang H, Wu Y, Hazebroek J, Meeley RB, Ertl DS. The maize low-phytic acid mutant lpa2 is caused by mutation in an inositol phosphate kinase gene. PLANT PHYSIOLOGY 2003; 131:507-15. [PMID: 12586875 PMCID: PMC166827 DOI: 10.1104/pp.014258] [Citation(s) in RCA: 125] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2002] [Revised: 10/11/2002] [Accepted: 11/06/2002] [Indexed: 05/18/2023]
Abstract
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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Affiliation(s)
- Jinrui Shi
- Pioneer Hi-Bred International, P.O. Box 1004, Johnston, Iowa 50131, USA.
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22
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Xia HJ, Brearley C, Elge S, Kaplan B, Fromm H, Mueller-Roeber B. Arabidopsis inositol polyphosphate 6-/3-kinase is a nuclear protein that complements a yeast mutant lacking a functional ArgR-Mcm1 transcription complex. THE PLANT CELL 2003; 15:449-63. [PMID: 12566584 PMCID: PMC141213 DOI: 10.1105/tpc.006676] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2002] [Accepted: 11/25/2002] [Indexed: 05/19/2023]
Abstract
Inositol 1,4,5-trisphosphate 3-kinase, and more generally inositol polyphosphate kinases (Ipk), play important roles in signal transduction in animal cells; however, their functions in plant cells remain to be elucidated. Here, we report the molecular cloning of a cDNA (AtIpk2beta) from a higher plant, Arabidopsis. Arabidopsis AtIpk2beta is a 33-kD protein that exhibits weak homology ( approximately 25% identical amino acids) with Ipk proteins from animals and yeast and lacks a calmodulin binding site, as revealed by sequence analysis and calmodulin binding assays. However, recombinant AtIpk2beta phosphorylates inositol 1,4,5-trisphosphate to inositol 1,4,5,6-tetrakisphosphate and also converts it to inositol 1,3,4,5,6-pentakisphosphate [Ins(1,3,4,5,6)P(5)]. AtIpk2beta also phosphorylates inositol 1,3,4,5-tetrakisphosphate to Ins(1,3,4,5,6)P(5). Thus, the enzyme is a D3/D6 dual-specificity inositol phosphate kinase. AtIpk2beta complements a yeast ARG82/IPK2 mutant lacking a functional ArgR-Mcm1 transcription complex. This complex is involved in regulating Arg metabolism-related gene expression and requires inositol polyphosphate kinase activity to function. AtIpk2beta was found to be located predominantly in the nucleus of plant cells, as demonstrated by immunolocalization and fusion to green fluorescent protein. RNA gel blot analysis and promoter-beta-glucuronidase reporter gene studies demonstrated AtIpk2beta gene expression in various organs tested. These data suggest a role for AtIpk2beta as a transcriptional control mediator in plants.
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Affiliation(s)
- Hui-Jun Xia
- Max-Planck-Institute of Molecular Plant Physiology, D-14424 Potsdam, Germany
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23
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Raboy V. Seeds for a better future: 'low phytate' grains help to overcome malnutrition and reduce pollution. TRENDS IN PLANT SCIENCE 2001; 6:458-62. [PMID: 11590064 DOI: 10.1016/s1360-1385(01)02104-5] [Citation(s) in RCA: 169] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
myo-Inositol(1,2,3,4,5,6)hexakisphosphate (InsP(6) or 'phytic acid') was first known as the storage form of phosphorus in seeds. Seed-derived dietary InsP(6) can contribute to iron and zinc deficiency in human populations. Excretion of 'phytic acid phosphorus' by non-ruminants such as poultry, swine and fish can contribute to water pollution. Sustainable solutions to these important problems might depend on progress in the molecular biology and genetics of InsP(6) accumulation during seed development. The development of 'low phytate' grain and legume genotypes could help advance our understanding of this biology, and when used in foods and feeds might help to reduce human malnutrition and reduce animal waste phosphorus.
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Affiliation(s)
- V Raboy
- US Department of Agriculture, Agricultural Research Service, 1691 So. 2700 W, PO Box 307, Aberdeen, ID 83210, USA.
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