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Improved Enzymatic Assay and Inhibition Analysis of Redox Membranotropic Enzymes, AtGALDH and TcGAL, Using a Reversed Micellar System. ANALYTICA 2022. [DOI: 10.3390/analytica3010004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Reversed micelles are helpful to solubilize otherwise insoluble membranotropic or membrane-bound enzymes in their functional form, thus enabling activity assay and inhibition analysis. However, in the case of redox enzymes, this task is further complicated by the necessity to select an appropriate electron-acceptor (EA) which, ideally, should be compatible with spectrophotometric measurements in reversed micelles. Here, we have identified such an EA and successfully used it in a reversed micellar environment to assay the activity of two homologous enzymes from mitochondria: l-galactone-1,4-lactone dehydrogenase (EC 1.3.2.3) from Arabidopsis thaliana (AtGALDH) and galactonolactone oxidase (EC 1.3.3.12) from Trypanosoma cruzi (TcGAL), differing in their membranotropic properties, with TcGAL being almost insoluble in water and particularly difficult to assay. Furthermore, we have demonstrated the possibility to use this assay for inhibition analysis, with an elucidation of the mechanism and inhibition parameters, which otherwise could not be possible. In order to perform inhibition analysis, we improved the approach for the determination of activity of such membrane enzymes based on a reversed micellar system as membrane matrix, necessary for the functioning of membrane enzymes. A number of electron acceptors (EA) were tested for AtGALDH and optimal conditions of activity determination for AtGALDH were found. The suggested method was successfully applied to the study of the inhibition of AtGALDH by lycorine, and the mixed competitive mechanism of inhibition of AtGALDH by lycorine was determined. The developed approach to inhibitor analysis was applied for TcGAL, insoluble in water membrane, and the method provides new opportunities for searching effective inhibitors that may be potential drugs. Indeed, galactonolactone oxidase from Trypanosoma cruzi (TcGAL) and AtGALDH are homologues, and the inhibition of TcGAL stops the vital biosynthesis of vitamin C in parasite Trypanosoma cruzi from causing Chagas disease. The approach proposed can be applied for the screening of inhibitors of AtGALDH and TcGAL, as well as to study properties of other membrane enzymes including determination of the mechanisms of inhibition, structure and catalytic properties, the impact of membrane components (for example lipids), and so on.
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Bulley SM, Cooney JM, Laing W. Elevating Ascorbate in Arabidopsis Stimulates the Production of Abscisic Acid, Phaseic Acid, and to a Lesser Extent Auxin (IAA) and Jasmonates, Resulting in Increased Expression of DHAR1 and Multiple Transcription Factors Associated with Abiotic Stress Tolerance. Int J Mol Sci 2021. [PMID: 34201662 DOI: 10.3990/ijms22136743] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/21/2023] Open
Abstract
Gene expression and phytohormone contents were measured in response to elevating ascorbate in the absence of other confounding stimuli such as high light and abiotic stresses. Young Arabidopsis plants were treated with 25 mM solutions of l-galactose pathway intermediates l-galactose (l-gal) or l-galactono-1,4-lactone (l-galL), as well as L-ascorbic acid (AsA), with 25 mM glucose used as control. Feeding increased rosette AsA 2- to 4-fold but there was little change in AsA biosynthetic gene transcripts. Of the ascorbate recycling genes, only Dehydroascorbate reductase 1 expression was increased. Some known regulatory genes displayed increased expression and included ANAC019, ANAC072, ATHB12, ZAT10 and ZAT12. Investigation of the ANAC019/ANAC072/ATHB12 gene regulatory network revealed a high proportion of ABA regulated genes. Measurement of a subset of jasmonate, ABA, auxin (IAA) and salicylic acid compounds revealed consistent increases in ABA (up to 4.2-fold) and phaseic acid (PA; up to 5-fold), and less consistently certain jasmonates, IAA, but no change in salicylic acid levels. Increased ABA is likely due to increased transcripts for the ABA biosynthetic gene NCED3. There were also smaller increases in transcripts for transcription factors ATHB7, ERD1, and ABF3. These results provide insights into how increasing AsA content can mediate increased abiotic stress tolerance.
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Affiliation(s)
- Sean M Bulley
- The New Zealand Institute for Plant and Food Research Limited, Te Puke 3182, New Zealand
| | - Janine M Cooney
- The New Zealand Institute for Plant and Food Research Limited, Ruakura, Hamilton 3214, New Zealand
| | - William Laing
- The New Zealand Institute for Plant and Food Research Limited, Palmerston North 4410, New Zealand
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3
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Bulley SM, Cooney JM, Laing W. Elevating Ascorbate in Arabidopsis Stimulates the Production of Abscisic Acid, Phaseic Acid, and to a Lesser Extent Auxin (IAA) and Jasmonates, Resulting in Increased Expression of DHAR1 and Multiple Transcription Factors Associated with Abiotic Stress Tolerance. Int J Mol Sci 2021; 22:ijms22136743. [PMID: 34201662 PMCID: PMC8269344 DOI: 10.3390/ijms22136743] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Accepted: 06/17/2021] [Indexed: 01/05/2023] Open
Abstract
Gene expression and phytohormone contents were measured in response to elevating ascorbate in the absence of other confounding stimuli such as high light and abiotic stresses. Young Arabidopsis plants were treated with 25 mM solutions of l-galactose pathway intermediates l-galactose (l-gal) or l-galactono-1,4-lactone (l-galL), as well as L-ascorbic acid (AsA), with 25 mM glucose used as control. Feeding increased rosette AsA 2- to 4-fold but there was little change in AsA biosynthetic gene transcripts. Of the ascorbate recycling genes, only Dehydroascorbate reductase 1 expression was increased. Some known regulatory genes displayed increased expression and included ANAC019, ANAC072, ATHB12, ZAT10 and ZAT12. Investigation of the ANAC019/ANAC072/ATHB12 gene regulatory network revealed a high proportion of ABA regulated genes. Measurement of a subset of jasmonate, ABA, auxin (IAA) and salicylic acid compounds revealed consistent increases in ABA (up to 4.2-fold) and phaseic acid (PA; up to 5-fold), and less consistently certain jasmonates, IAA, but no change in salicylic acid levels. Increased ABA is likely due to increased transcripts for the ABA biosynthetic gene NCED3. There were also smaller increases in transcripts for transcription factors ATHB7, ERD1, and ABF3. These results provide insights into how increasing AsA content can mediate increased abiotic stress tolerance.
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Affiliation(s)
- Sean M. Bulley
- The New Zealand Institute for Plant and Food Research Limited, Te Puke 3182, New Zealand
- Correspondence: ; Tel.: +64-7-928-9796
| | - Janine M. Cooney
- The New Zealand Institute for Plant and Food Research Limited, Ruakura, Hamilton 3214, New Zealand;
| | - William Laing
- The New Zealand Institute for Plant and Food Research Limited, Palmerston North 4410, New Zealand;
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Chen W, Hu T, Ye J, Wang B, Liu G, Wang Y, Yuan L, Li J, Li F, Ye Z, Zhang Y. A CCAAT-binding factor, SlNFYA10, negatively regulates ascorbate accumulation by modulating the D-mannose/L-galactose pathway in tomato. HORTICULTURE RESEARCH 2020; 7:200. [PMID: 33328457 PMCID: PMC7705693 DOI: 10.1038/s41438-020-00418-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 08/15/2020] [Accepted: 08/18/2020] [Indexed: 05/04/2023]
Abstract
Ascorbic acid (AsA), an important antioxidant and growth regulator, and it is essential for plant development and human health. Specifically, humans have to acquire AsA from dietary sources due to their inability to synthesize it. The AsA biosynthesis pathway in plants has been elucidated, but its regulatory mechanism remains largely unknown. In this report, we biochemically identified a CCAAT-box transcription factor (SlNFYA10) that can bind to the promoter of SlGME1, which encodes GDP-Man-3',5'-epimerase, a pivotal enzyme in the D-mannose/L-galactose pathway. Importantly, SlNFYA10 simultaneously binds to the promoter of SlGGP1, a downstream gene of SlGME1 in the D-mannose/L-galactose pathway. Binding assays in yeast and functional analyses in plants have confirmed that SlNFYA10 exerts a negative effect on the expression of both SlGME1 and SlGGP1. Transgenic tomato lines overexpressing SlNFYA10 show decreased levels of SlGME1 and SlGGP1 abundance and AsA concentration in their leaves and fruits, accompanied by enhanced sensitivity to oxidative stress. Overall, SlNFYA10 is the first CCAAT-binding factor identified to date to negatively regulate the AsA biosynthetic pathway at multiple sites and modulate plant responses to oxidative stress.
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Affiliation(s)
- Weifang Chen
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, 430070, Wuhan, China
| | - Tixu Hu
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, 430070, Wuhan, China
| | - Jie Ye
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, 430070, Wuhan, China
| | - Bing Wang
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, 430070, Wuhan, China
| | - Genzhong Liu
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, 430070, Wuhan, China
| | - Ying Wang
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, 430070, Wuhan, China
| | - Lei Yuan
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, 430070, Wuhan, China
| | - Jiaming Li
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, 430070, Wuhan, China
| | - Fangman Li
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, 430070, Wuhan, China
| | - Zhibiao Ye
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, 430070, Wuhan, China
- HZAU Chuwei Institute of Advanced Seeds, 430070, Wuhan, China
| | - Yuyang Zhang
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, 430070, Wuhan, China.
- HZAU Chuwei Institute of Advanced Seeds, 430070, Wuhan, China.
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Yabuta Y, Nagata R, Aoki Y, Kariya A, Wada K, Yanagimoto A, Hara H, Bito T, Okamoto N, Yoshida S, Ishihara A, Watanabe F. L-Ascorbate Biosynthesis Involves Carbon Skeleton Rearrangement in the Nematode Caenorhabditis elegans. Metabolites 2020; 10:metabo10080334. [PMID: 32824560 PMCID: PMC7463950 DOI: 10.3390/metabo10080334] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 08/11/2020] [Accepted: 08/15/2020] [Indexed: 11/16/2022] Open
Abstract
Ascorbate (AsA) is required as a cofactor and is widely distributed in plants and animals. Recently, it has been suggested that the nematode Caenorhabditis elegans also synthesizes AsA. However, its biosynthetic pathway is still unknown. To further understand AsA biosynthesis in C. elegans, we analyzed the incorporation of the 13C atom into AsA using gas chromatography-mass spectrometry (GC-MS) in worms fed with D-Glc (1-13C)-labeled Escherichia coli. GC-MS analysis revealed that AsA biosynthesis in C. elegans, similarly to that in mammalian systems, involves carbon skeleton rearrangement. The addition of L-gulono-1,4-lactone, an AsA precursor in the mammalian pathway, significantly increased AsA level in C. elegans, whereas the addition of L-galactono-1,4-lactone, an AsA precursor in the plant and Euglena pathway, did not affect AsA level. The suppression of E03H4.3 (an ortholog of gluconolactonase) or the deficiency of F54D5.12 (an ortholog of L-gulono-1,4-lactone oxidase) significantly decreased AsA level in C. elegans. Although N2- and AsA-deficient F54D5.12 knockout mutant worm (tm6671) morphologies and the ratio of collagen to non-collagen protein did not show any significant differences, the mutant worms exhibited increased malondialdehyde levels and reduced lifespan compared with the N2 worms. In conclusion, our findings indicate that the AsA biosynthetic pathway is similar in C. elegans and mammals.
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Affiliation(s)
- Yukinori Yabuta
- Department of Agricultural, Life and Environmental Sciences, Faculty of Agriculture, Tottori University, 4-101 Koyama-Minami, Tottori 680-8553, Japan; (R.N.); (Y.A.); (A.K.); (K.W.); (A.Y.); (H.H.); (T.B.); (A.I.); (F.W.)
- Correspondence: ; Tel.: +81-857-31-5382
| | - Ryuta Nagata
- Department of Agricultural, Life and Environmental Sciences, Faculty of Agriculture, Tottori University, 4-101 Koyama-Minami, Tottori 680-8553, Japan; (R.N.); (Y.A.); (A.K.); (K.W.); (A.Y.); (H.H.); (T.B.); (A.I.); (F.W.)
| | - Yuka Aoki
- Department of Agricultural, Life and Environmental Sciences, Faculty of Agriculture, Tottori University, 4-101 Koyama-Minami, Tottori 680-8553, Japan; (R.N.); (Y.A.); (A.K.); (K.W.); (A.Y.); (H.H.); (T.B.); (A.I.); (F.W.)
| | - Ayumi Kariya
- Department of Agricultural, Life and Environmental Sciences, Faculty of Agriculture, Tottori University, 4-101 Koyama-Minami, Tottori 680-8553, Japan; (R.N.); (Y.A.); (A.K.); (K.W.); (A.Y.); (H.H.); (T.B.); (A.I.); (F.W.)
| | - Kousuke Wada
- Department of Agricultural, Life and Environmental Sciences, Faculty of Agriculture, Tottori University, 4-101 Koyama-Minami, Tottori 680-8553, Japan; (R.N.); (Y.A.); (A.K.); (K.W.); (A.Y.); (H.H.); (T.B.); (A.I.); (F.W.)
| | - Ayako Yanagimoto
- Department of Agricultural, Life and Environmental Sciences, Faculty of Agriculture, Tottori University, 4-101 Koyama-Minami, Tottori 680-8553, Japan; (R.N.); (Y.A.); (A.K.); (K.W.); (A.Y.); (H.H.); (T.B.); (A.I.); (F.W.)
| | - Hiroka Hara
- Department of Agricultural, Life and Environmental Sciences, Faculty of Agriculture, Tottori University, 4-101 Koyama-Minami, Tottori 680-8553, Japan; (R.N.); (Y.A.); (A.K.); (K.W.); (A.Y.); (H.H.); (T.B.); (A.I.); (F.W.)
| | - Tomohiro Bito
- Department of Agricultural, Life and Environmental Sciences, Faculty of Agriculture, Tottori University, 4-101 Koyama-Minami, Tottori 680-8553, Japan; (R.N.); (Y.A.); (A.K.); (K.W.); (A.Y.); (H.H.); (T.B.); (A.I.); (F.W.)
| | - Naho Okamoto
- The United Graduate School of Agricultural Sciences, Tottori University, 4-101 Koyama-Minami, Tottori 680-8553, Japan;
| | - Shinichi Yoshida
- Electronic and Organic Material Laboratory, Tottori Institute of Industrial Technology, 7-1-1 Wakabadai-minami, Tottori 689-1112, Japan;
| | - Atsushi Ishihara
- Department of Agricultural, Life and Environmental Sciences, Faculty of Agriculture, Tottori University, 4-101 Koyama-Minami, Tottori 680-8553, Japan; (R.N.); (Y.A.); (A.K.); (K.W.); (A.Y.); (H.H.); (T.B.); (A.I.); (F.W.)
| | - Fumio Watanabe
- Department of Agricultural, Life and Environmental Sciences, Faculty of Agriculture, Tottori University, 4-101 Koyama-Minami, Tottori 680-8553, Japan; (R.N.); (Y.A.); (A.K.); (K.W.); (A.Y.); (H.H.); (T.B.); (A.I.); (F.W.)
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Tyapkina DY, Kochieva EZ, Slugina MA. Vitamin C in fleshy fruits: biosynthesis, recycling, genes, and enzymes. Vavilovskii Zhurnal Genet Selektsii 2019. [DOI: 10.18699/vj19.492] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
L-ascorbic acid (vitamin C) is a plant secondary metabolite that has a variety of functions both in plant tissues and in the human body. Plants are the main source of vitamin C in human nutrition, especially citrus, rose hip, tomato, strawberry, pepper, papaya, kiwi, and currant fruits. However, in spite of the biological significance of L-ascorbic acid, the pathways of its biosynthesis in plants were fully understood only in 2007 by the example of a model plant Arabidopsis thaliana. In the present review, the main biosynthetic pathways of vitamin C are described: the L-galactose pathway, L-gulose pathway, galacturonic and myo-inositol pathway. To date, the best studied is the L-galactose pathway (Smyrnoff–Wheeler pathway). Only for this pathway all the enzymes and the entire cascade of reactions have been described. For other pathways, only hypothetical metabolites are proposed and not all the catalyzing enzymes have been identified. The key genes participating in ascorbic acid biosynthesis and accumulation in fleshy fruits are highlighted. Among them are L-galactose pathway proteins (GDP-mannose phosphorylase (GMP, VTC1), GDP-D-mannose epimerase (GME), GDP-L-galactose phosphorylase (GGP, VTC2/VTC5), L-galactose-1-phosphate phosphatase (GPP/VTC4), L-galactose-1-dehydrogenase (GalDH), and L-galactono1,4-lactone dehydrogenase (GalLDH)); D-galacturonic pathway enzymes (NADPH-dependent D-galacturonate reductase (GalUR)); and proteins, controlling the recycling of ascorbic acid (dehydroascorbate reductase (DHAR1) and monodehydroascorbate reductase (MDHAR)). Until now, there is no clear and unequivocal evidence for the existence of one predominant pathway of vitamin C biosynthesis in fleshy fruits. For example, the L-galactose pathway is predominant in peach and kiwi fruits, whereas the D-galacturonic pathway seems to be the most essential in grape and strawberry fruits. However, in some plants, such as citrus and tomato fruits, there is a switch between different pathways during ripening. It is noted that the final ascorbic acid content in fruits depends not only on biosynthesis but also on the rate of its oxidation and recirculation.
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Affiliation(s)
- D. Y. Tyapkina
- Institute of Bioengineering, Research Center of Biotechnology, RAS
| | - E. Z. Kochieva
- Institute of Bioengineering, Research Center of Biotechnology, RAS;
Lomonosov Moscow State University
| | - M. A. Slugina
- Institute of Bioengineering, Research Center of Biotechnology, RAS;
Lomonosov Moscow State University
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Fenech M, Amaya I, Valpuesta V, Botella MA. Vitamin C Content in Fruits: Biosynthesis and Regulation. FRONTIERS IN PLANT SCIENCE 2019; 9:2006. [PMID: 30733729 PMCID: PMC6353827 DOI: 10.3389/fpls.2018.02006] [Citation(s) in RCA: 122] [Impact Index Per Article: 24.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Accepted: 12/31/2018] [Indexed: 05/19/2023]
Abstract
Throughout evolution, a number of animals including humans have lost the ability to synthesize ascorbic acid (ascorbate, vitamin C), an essential molecule in the physiology of animals and plants. In addition to its main role as an antioxidant and cofactor in redox reactions, recent reports have shown an important role of ascorbate in the activation of epigenetic mechanisms controlling cell differentiation, dysregulation of which can lead to the development of certain types of cancer. Although fruits and vegetables constitute the main source of ascorbate in the human diet, rising its content has not been a major breeding goal, despite the large inter- and intraspecific variation in ascorbate content in fruit crops. Nowadays, there is an increasing interest to boost ascorbate content, not only to improve fruit quality but also to generate crops with elevated stress tolerance. Several attempts to increase ascorbate in fruits have achieved fairly good results but, in some cases, detrimental effects in fruit development also occur, likely due to the interaction between the biosynthesis of ascorbate and components of the cell wall. Plants synthesize ascorbate de novo mainly through the Smirnoff-Wheeler pathway, the dominant pathway in photosynthetic tissues. Two intermediates of the Smirnoff-Wheeler pathway, GDP-D-mannose and GDP-L-galactose, are also precursors of the non-cellulosic components of the plant cell wall. Therefore, a better understanding of ascorbate biosynthesis and regulation is essential for generation of improved fruits without developmental side effects. This is likely to involve a yet unknown tight regulation enabling plant growth and development, without impairing the cell redox state modulated by ascorbate pool. In certain fruits and developmental conditions, an alternative pathway from D-galacturonate might be also relevant. We here review the regulation of ascorbate synthesis, its close connection with the cell wall, as well as different strategies to increase its content in plants, with a special focus on fruits.
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Affiliation(s)
- Mario Fenech
- Departamento de Biología Molecular y Bioquímica, Instituto de Hortofruticultura Subtropical y Mediterránea (IHSM), Consejo Superior de Investigaciones Científicas, Universidad de Málaga, Málaga, Spain
| | - Iraida Amaya
- Instituto Andaluz de Investigación y Formación Agraria y Pesquera, Area de Genómica y Biotecnología, Centro de Málaga, Spain
| | - Victoriano Valpuesta
- Departamento de Biología Molecular y Bioquímica, Instituto de Hortofruticultura Subtropical y Mediterránea (IHSM), Consejo Superior de Investigaciones Científicas, Universidad de Málaga, Málaga, Spain
| | - Miguel A. Botella
- Departamento de Biología Molecular y Bioquímica, Instituto de Hortofruticultura Subtropical y Mediterránea (IHSM), Consejo Superior de Investigaciones Científicas, Universidad de Málaga, Málaga, Spain
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Strobbe S, De Lepeleire J, Van Der Straeten D. From in planta Function to Vitamin-Rich Food Crops: The ACE of Biofortification. FRONTIERS IN PLANT SCIENCE 2018; 9:1862. [PMID: 30619424 PMCID: PMC6305313 DOI: 10.3389/fpls.2018.01862] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Accepted: 12/03/2018] [Indexed: 05/11/2023]
Abstract
Humans are highly dependent on plants to reach their dietary requirements, as plant products contribute both to energy and essential nutrients. For many decades, plant breeders have been able to gradually increase yields of several staple crops, thereby alleviating nutritional needs with varying degrees of success. However, many staple crops such as rice, wheat and corn, although delivering sufficient calories, fail to satisfy micronutrient demands, causing the so called 'hidden hunger.' Biofortification, the process of augmenting nutritional quality of food through the use of agricultural methodologies, is a pivotal asset in the fight against micronutrient malnutrition, mainly due to vitamin and mineral deficiencies. Several technical advances have led to recent breakthroughs. Nutritional genomics has come to fruition based on marker-assisted breeding enabling rapid identification of micronutrient related quantitative trait loci (QTL) in the germplasm of interest. As a complement to these breeding techniques, metabolic engineering approaches, relying on a continuously growing fundamental knowledge of plant metabolism, are able to overcome some of the inevitable pitfalls of breeding. Alteration of micronutrient levels does also require fundamental knowledge about their role and influence on plant growth and development. This review focuses on our knowledge about provitamin A (beta-carotene), vitamin C (ascorbate) and the vitamin E group (tocochromanols). We begin by providing an overview of the functions of these vitamins in planta, followed by highlighting some of the achievements in the nutritional enhancement of food crops via conventional breeding and genetic modification, concluding with an evaluation of the need for such biofortification interventions. The review further elaborates on the vast potential of creating nutritionally enhanced crops through multi-pathway engineering and the synergistic potential of conventional breeding in combination with genetic engineering, including the impact of novel genome editing technologies.
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Aboobucker SI, Suza WP, Lorence A. Characterization of Two Arabidopsis L-Gulono-1,4-lactone Oxidases, AtGulLO3 and AtGulLO5, Involved in Ascorbate Biosynthesis. REACTIVE OXYGEN SPECIES (APEX, N.C.) 2017; 4:389-417. [PMID: 30112455 PMCID: PMC6088757 DOI: 10.20455/ros.2017.861] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
L-Ascorbic acid (AsA, vitamin C) is an essential antioxidant for plants and animals. There are four known ascorbate biosynthetic pathways in plants: the L-galactose, L-gulose, D-galacturonate, and myo-inositol routes. These pathways converge into two AsA precursors: L-galactono-1,4-lactone and L-gulono-1,4-lactone (L-GulL). This work focuses on the study of L-gulono-1,4-lactone oxidase (GulLO), the enzyme that works at the intersect of the gulose and inositol pathways. Previous studies have shown that feeding L-gulono-1,4-lactone to multiple plants leads to increased AsA. There are also reports showing GulLO activity in plants. We describe the first detailed characterization of a plant enzyme specific to oxidize L-GulL to AsA. We successfully purified a recombinant Arabidopsis GulLO enzyme (called AtGulLO5) in a transient expression system. The biochemical properties of this enzyme are similar to the ones of bacterial isozymes in terms of substrate specificity, subcellular localization, use of flavin adenine dinucleotide (FAD) as electron acceptor, and specific activity. AtGulLO5 is an exclusive dehydrogenase with an absolute specificity for L-GulL as substrate thus differing from the existing plant L-galactono-1,4-lactone dehydrogenases and mammalian GulLOs. Feeding L-GulL to N. benthamiana leaves expressing AtGulLO5 constructs led to increased foliar AsA content, but it was not different from that of controls, most likely due to the observed low catalytic efficiency of AtGulLO5. Similar results were also obtained with another member of the AtGulLO family (AtGulLO3) that appears to have a rapid protein turnover. We propose that AsA synthesis through L-GulL in plants is regulated at the post-transcriptional level by limiting GulLO enzyme availability.
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Affiliation(s)
- Siddique I Aboobucker
- Arkansas Biosciences Institute, Arkansas State University, P.O. Box 639, State University, AR 72467, USA
- Current address: 2104 Agronomy Hall, Iowa State University, Ames, IA 50011, USA
| | - Walter P Suza
- Arkansas Biosciences Institute, Arkansas State University, P.O. Box 639, State University, AR 72467, USA
- Current address: 2104 Agronomy Hall, Iowa State University, Ames, IA 50011, USA
| | - Argelia Lorence
- Arkansas Biosciences Institute, Arkansas State University, P.O. Box 639, State University, AR 72467, USA
- Department of Chemistry and Physics, Arkansas State University, P.O. Box 419, State University, AR 72467, USA
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Ewing TA, Fraaije MW, Mattevi A, van Berkel WJ. The VAO/PCMH flavoprotein family. Arch Biochem Biophys 2017; 632:104-117. [DOI: 10.1016/j.abb.2017.06.022] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Revised: 06/26/2017] [Accepted: 06/29/2017] [Indexed: 01/15/2023]
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11
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Rodríguez-Ruiz M, Mateos RM, Codesido V, Corpas FJ, Palma JM. Characterization of the galactono-1,4-lactone dehydrogenase from pepper fruits and its modulation in the ascorbate biosynthesis. Role of nitric oxide. Redox Biol 2017; 12:171-181. [PMID: 28242561 PMCID: PMC5328913 DOI: 10.1016/j.redox.2017.02.009] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Revised: 01/15/2017] [Accepted: 02/12/2017] [Indexed: 12/23/2022] Open
Abstract
Pepper fruit is one of the highest vitamin C sources of plant origin for our diet. In plants, ascorbic acid is mainly synthesized through the L-galactose pathway, being the L-galactono-1,4-lactone dehydrogenase (GalLDH) the last step. Using pepper fruits, the full GalLDH gene was cloned and the protein molecular characterization accomplished. GalLDH protein sequence (586 residues) showed a 37 amino acids signal peptide at the N-terminus, characteristic of mitochondria. The hydrophobic analysis of the mature protein displayed one transmembrane helix comprising 20 amino acids at the N-terminus. By using a polyclonal antibody raised against a GalLDH internal sequence and immunoblotting analysis, a 56kDa polypeptide cross-reacted with pepper fruit samples. Using leaves, flowers, stems and fruits, the expression of GalLDH by qRT-PCR and the enzyme activity were analyzed, and results indicate that GalLDH is a key player in the physiology of pepper plants, being possibly involved in the processes which undertake the transport of ascorbate among different organs. We also report that an NO (nitric oxide)-enriched atmosphere enhanced ascorbate content in pepper fruits about 40% parallel to increased GalLDH gene expression and enzyme activity. This is the first report on the stimulating effect of NO treatment on the vitamin C concentration in plants. Accordingly, the modulation by NO of GalLDH was addressed. In vitro enzymatic assays of GalLDH were performed in the presence of SIN-1 (peroxynitrite donor) and S-nitrosoglutahione (NO donor). Combined results of in vivo NO treatment and in vitro assays showed that NO provoked the regulation of GalLDH at transcriptional and post-transcriptional levels, but not post-translational modifications through nitration or S-nitrosylation events promoted by reactive nitrogen species (RNS) took place. These results suggest that this modulation point of the ascorbate biosynthesis could be potentially used for biotechnological purposes to increase the vitamin C levels in pepper fruits.
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Affiliation(s)
- Marta Rodríguez-Ruiz
- Group of Antioxidants, Free Radicals and Nitric Oxide in Biotechnology, Food and Agriculture, Dept. Biochemistry, Cell and Molecular Biology of Plants, Estación Experimental del Zaidín, CSIC, C/ Profesor Albareda, 1, 18008 Granada, Spain.
| | - Rosa M Mateos
- University Hospital Puerta del Mar, Avenida Ana de Viya, 21, Cádiz 11009, Spain.
| | - Verónica Codesido
- Phytoplant Research S.L, Rabanales 21 - The Science and Technology Park of Córdoba, C/ Astrónoma Cecilia Payne, Edificio Centauro, módulo B-1, 14014 Córdoba, Spain.
| | - Francisco J Corpas
- Group of Antioxidants, Free Radicals and Nitric Oxide in Biotechnology, Food and Agriculture, Dept. Biochemistry, Cell and Molecular Biology of Plants, Estación Experimental del Zaidín, CSIC, C/ Profesor Albareda, 1, 18008 Granada, Spain.
| | - José M Palma
- Group of Antioxidants, Free Radicals and Nitric Oxide in Biotechnology, Food and Agriculture, Dept. Biochemistry, Cell and Molecular Biology of Plants, Estación Experimental del Zaidín, CSIC, C/ Profesor Albareda, 1, 18008 Granada, Spain.
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12
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Subrahmanian N, Remacle C, Hamel PP. Plant mitochondrial Complex I composition and assembly: A review. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2016; 1857:1001-14. [PMID: 26801215 DOI: 10.1016/j.bbabio.2016.01.009] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Revised: 01/18/2016] [Accepted: 01/18/2016] [Indexed: 12/31/2022]
Abstract
In the mitochondrial inner membrane, oxidative phosphorylation generates ATP via the operation of several multimeric enzymes. The proton-pumping Complex I (NADH:ubiquinone oxidoreductase) is the first and most complicated enzyme required in this process. Complex I is an L-shaped enzyme consisting of more than 40 subunits, one FMN molecule and eight Fe-S clusters. In recent years, genetic and proteomic analyses of Complex I mutants in various model systems, including plants, have provided valuable insights into the assembly of this multimeric enzyme. Assisted by a number of key players, referred to as "assembly factors", the assembly of Complex I takes place in a sequential and modular manner. Although a number of factors have been identified, their precise function in mediating Complex I assembly still remains to be elucidated. This review summarizes our current knowledge of plant Complex I composition and assembly derived from studies in plant model systems such as Arabidopsis thaliana and Chlamydomonas reinhardtii. Plant Complex I is highly conserved and comprises a significant number of subunits also present in mammalian and fungal Complexes I. Plant Complex I also contains additional subunits absent from the mammalian and fungal counterpart, whose function in enzyme activity and assembly is not clearly understood. While 14 assembly factors have been identified for human Complex I, only two proteins, namely GLDH and INDH, have been established as bona fide assembly factors for plant Complex I. This article is part of a Special Issue entitled Respiratory complex I, edited by Volker Zickermann and Ulrich Brandt.
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Affiliation(s)
- Nitya Subrahmanian
- The Ohio State University, Department of Molecular Genetics, 500 Aronoff Laboratory, 318 W. 12th Avenue, Columbus, OH 43210, USA
| | - Claire Remacle
- Institute of Botany, Department of Life Sciences, University of Liège, 4000 Liège, Belgium
| | - Patrice Paul Hamel
- The Ohio State University, Department of Molecular Genetics, 500 Aronoff Laboratory, 318 W. 12th Avenue, Columbus, OH 43210, USA; The Ohio State University, Department of Biological Chemistry and Pharmacology, 500 Aronoff Laboratory, 318 W. 12th Avenue, Columbus, OH 43210, USA.
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13
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Hu T, Ye J, Tao P, Li H, Zhang J, Zhang Y, Ye Z. The tomato HD-Zip I transcription factor SlHZ24 modulates ascorbate accumulation through positive regulation of the D-mannose/L-galactose pathway. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2016; 85:16-29. [PMID: 26610866 DOI: 10.1111/tpj.13085] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Revised: 11/12/2015] [Accepted: 11/16/2015] [Indexed: 05/03/2023]
Abstract
Ascorbate (AsA) is an antioxidant that can scavenge the reactive oxygen species (ROS) produced when plants encounter stressful conditions. Here, it was revealed by a yeast one-hybrid assay that a tomato (Solanum lycopersicum) HD-Zip I family transcription factor, SlHZ24, binds to the promoter of an AsA biosynthetic gene encoding GDP-D-mannose pyrophosphorylase 3 (SlGMP3). Both the transient expression system and electrophoretic mobility shift assay (EMSA) showed that SlHZ24 binds to a regulatory cis-element in the SlGMP3 promoter, and further overexpression of SlHZ24 in transgenic tomato lines resulted in increased AsA levels. In contrast, suppressing expression of the gene using RNA interference (RNAi) had the opposite effect. These data suggest that SlHZ24 can positively regulate the accumulation of AsA, and in support of this it was shown that SlGMP3 expression increased in the SlHZ24-overexpressing lines and declined in SlHZ24-RNAi lines. SlHZ24 also affected the expression of other genes in the D-mannose/L-galactose pathway, such as genes encoding GDP-mannose-3',5'-epimerase 2 (SlGME2), GDP-L-galactose phosphorylase (SlGGP) and SlGMP4. The EMSA indicated that SlHZ24 bound to the promoters of SlGME2 and SlGGP, suggesting multi-targeted regulation of AsA biosynthesis. Finally, SlHZ24-overexpressing plants showed less sensitivity to oxidative stress; we therefore conclude that SlHZ24 promotes AsA biosynthesis, which in turn enhances oxidative stress tolerance.
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Affiliation(s)
- Tixu Hu
- The Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, 430070, China
| | - Jie Ye
- The Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, 430070, China
| | - Peiwen Tao
- The Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, 430070, China
| | - Hanxia Li
- The Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, 430070, China
| | - Junhong Zhang
- The Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, 430070, China
| | - Yuyang Zhang
- The Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, 430070, China
| | - Zhibiao Ye
- The Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, 430070, China
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Aboobucker SI, Lorence A. Recent progress on the characterization of aldonolactone oxidoreductases. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2016; 98:171-85. [PMID: 26696130 PMCID: PMC4725720 DOI: 10.1016/j.plaphy.2015.11.017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Revised: 11/23/2015] [Accepted: 11/24/2015] [Indexed: 06/05/2023]
Abstract
L-Ascorbic acid (ascorbate, AsA, vitamin C) is essential for animal and plant health. Despite our dependence on fruits and vegetables to fulfill our requirement for this vitamin, the metabolic network leading to its formation in plants is just being fully elucidated. There is evidence supporting the operation of at least four biosynthetic pathways leading to AsA formation in plants. These routes use D-mannose/L-galactose, L-gulose, D-galacturonate, and myo-inositol as the main precursors. This review focuses on aldonolactone oxidoreductases, a subgroup of the vanillyl alcohol oxidase (VAO; EC 1.1.3.38) superfamily, enzymes that catalyze the terminal step in AsA biosynthesis in bacteria, protozoa, animals, and plants. In this report, we review the properties of well characterized aldonolactone oxidoreductases to date. A shared feature in these proteins is the presence of a flavin cofactor as well as a thiol group. The flavin cofactor in many cases is bound to the N terminus of the enzymes or to a recently discovered HWXK motif in the C terminus. The binding between the flavin moiety and the protein can be either covalent or non-covalent. Substrate specificity and subcellular localization differ among the isozymes of each kingdom. All oxidases among these enzymes possess dehydrogenase activity, however, exclusive dehydrogenases are also found. We also discuss recent evidence indicating that plants have both L-gulono-1,4-lactone oxidases and L-galactono-1,4-lactone dehydrogenases involved in AsA biosynthesis.
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Affiliation(s)
- Siddique I Aboobucker
- Arkansas Biosciences Institute, Arkansas State University, P.O. Box 639, State University, AR 72467, USA
| | - Argelia Lorence
- Arkansas Biosciences Institute, Arkansas State University, P.O. Box 639, State University, AR 72467, USA; Department of Chemistry and Physics, Arkansas State University, P.O. Box 419, State University, AR 72467, USA.
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15
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Venkatesh J, Park SW. Role of L-ascorbate in alleviating abiotic stresses in crop plants. BOTANICAL STUDIES 2014; 55:38. [PMID: 28510969 PMCID: PMC5432849 DOI: 10.1186/1999-3110-55-38] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2012] [Accepted: 12/16/2013] [Indexed: 05/21/2023]
Abstract
L-ascorbic acid (vitamin C) is a major antioxidant in plants and plays a significant role in mitigation of excessive cellular reactive oxygen species activities caused by number of abiotic stresses. Plant ascorbate levels change differentially in response to varying environmental stress conditions, depending on the degree of stress and species sensitivity. Successful modulation of ascorbate biosynthesis through genetic manipulation of genes involved in biosynthesis, catabolism and recycling of ascorbate has been achieved. Recently, role of ascorbate in alleviating number of abiotic stresses has been highlighted in crop plants. In this article, we discuss the current understanding of ascorbate biosynthesis and its antioxidant role in order to increase our comprehension of how ascorbate helps plants to counteract or cope with various abiotic stresses.
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Affiliation(s)
- Jelli Venkatesh
- Department of Molecular Biotechnology, Konkuk University, 1, Hwayang-dong, Seoul, Gwangjin-gu South Korea
| | - Se Won Park
- Department of Molecular Biotechnology, Konkuk University, 1, Hwayang-dong, Seoul, Gwangjin-gu South Korea
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16
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Anjum NA, Gill SS, Gill R, Hasanuzzaman M, Duarte AC, Pereira E, Ahmad I, Tuteja R, Tuteja N. Metal/metalloid stress tolerance in plants: role of ascorbate, its redox couple, and associated enzymes. PROTOPLASMA 2014; 251:1265-83. [PMID: 24682425 DOI: 10.1007/s00709-014-0636-x] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Accepted: 03/11/2014] [Indexed: 05/23/2023]
Abstract
The enhanced generation of reactive oxygen species (ROS) under metal/metalloid stress is most common in plants, and the elevated ROS must be successfully metabolized in order to maintain plant growth, development, and productivity. Ascorbate (AsA) is a highly abundant metabolite and a water-soluble antioxidant, which besides positively influencing various aspects in plants acts also as an enigmatic component of plant defense armory. As a significant component of the ascorbate-glutathione (AsA-GSH) pathway, it performs multiple vital functions in plants including growth and development by either directly or indirectly metabolizing ROS and its products. Enzymes such as monodehydroascorbate reductase (MDHAR, EC 1.6.5.4) and dehydroascorbate reductase (DHAR, EC 1.8.5.1) maintain the reduced form of AsA pool besides metabolically controlling the ratio of AsA with its oxidized form (dehydroascorbate, DHA). Ascorbate peroxidase (APX, EC 1.11.1.11) utilizes the reduced AsA pool as the specific electron donor during ROS metabolism. Thus, AsA, its redox couple (AsA/DHA), and related enzymes (MDHAR, DHAR, and APX) cumulatively form an AsA redox system to efficiently protect plants particularly against potential anomalies caused by ROS and its products. Here we present a critical assessment of the recent research reports available on metal/metalloid-accrued modulation of reduced AsA pool, AsA/DHA redox couple and AsA-related major enzymes, and the cumulative significance of these antioxidant system components in plant metal/metalloid stress tolerance.
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Affiliation(s)
- Naser A Anjum
- Centre for Environmental and Marine Studies (CESAM) and Department of Chemistry, University of Aveiro, 3810-193, Aveiro, Portugal,
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17
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Alós E, Rodrigo MJ, Zacarías L. Differential transcriptional regulation of L-ascorbic acid content in peel and pulp of citrus fruits during development and maturation. PLANTA 2014; 239:1113-28. [PMID: 24567029 DOI: 10.1007/s00425-014-2044-z] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Accepted: 02/06/2014] [Indexed: 05/09/2023]
Abstract
Citrus fruits are an important source of ascorbic acid (AsA) for human nutrition, but the main pathways involved in its biosynthesis and their regulation are still not fully characterized. To study the transcriptional regulation of AsA accumulation, expression levels of 13 genes involved in AsA biosynthesis, 5 in recycling and 5 in degradation were analyzed in peel and pulp of fruit of two varieties with different AsA concentration: Navel orange (Citrus sinensis) and Satsuma mandarin (Citrus unshiu). AsA accumulation in peel and pulp correlated with the transcriptional profiling of the L-galactose pathway genes, and the myo-inositol pathway appeared to be also relevant in the peel of immature-green orange. Differences in AsA content between varieties were associated with differential gene expression of GDP-mannose pyrophosphorylase (GMP), GDP-L-galactose phosphorylase (GGP) and L-galactose-1-phosphate phosphatase (GPP), myo-inositol oxygenase in peel, and GGP and GPP in pulp. Relative expressions of monodehydroascorbate reductase 3 (MDHAR3) and dehydroascorbate reductase1 (DHAR1) correlated with AsA accumulation during development and ripening in peel and pulp, respectively, and were more highly expressed in the variety with higher AsA contents. Collectively, results indicated a differential regulation of AsA concentration in peel and pulp of citrus fruits that may change during the different stages of fruit development. The L-galactose pathway appears to be predominant in both tissues, but AsA concentration is regulated by complex mechanisms in which degradation and recycling also play important roles.
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Affiliation(s)
- Enriqueta Alós
- Instituto de Agroquímica y Tecnología de Alimentos (IATA), Consejo Superior de Investigaciones Científicas (CSIC), Avda. Agustín Escardino 7, Paterna, 46980, Valencia, Spain,
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18
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Aldonolactone oxidoreductases. Methods Mol Biol 2014; 1146:95-111. [PMID: 24764090 DOI: 10.1007/978-1-4939-0452-5_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Abstract
Vitamin C is a widely used vitamin. Here we review the occurrence and properties of aldonolactone oxidoreductases, an important group of flavoenzymes responsible for the ultimate production of vitamin C and its analogs in animals, plants, and single-cell organisms.
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Cao Z, Yang P, Zhou Q. Multiple biological functions and pharmacological effects of lycorine. Sci China Chem 2013; 56:1382-1391. [PMID: 32215001 PMCID: PMC7088923 DOI: 10.1007/s11426-013-4967-9] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2013] [Accepted: 06/28/2013] [Indexed: 12/20/2022]
Abstract
Lycorine is the major active component from the amaryllidaceae family plant Lycoris radiate, a represent traditional Chinese medicinal herb, and is one of the typical alkaloids with pyrrolophenanthridine nucleus core. Lycorine has drawn great interest in medicinal field due to its divergent chemical structures and multiple biological functions, as well as pharmacological effects on various diseases. Accumulated evidence shows that lycorine not only possesses strong pharmacological effects on many diseases, including anti-leukemia, anti-tumor, anti-angiogenesis, anti-virus, anti-bacteria, anti-inflammation, and antimalaria, but also exerts many other biological functions, such as inhibition of acetylcholinesterase and topoisomerase, suppression of ascorbic acid biosynthesis, and control of circadian period length. Notably, lycorine exhibits its numerous pharmacological effects on various diseases with very low toxicity and mild side effects. The divergent chemical structures, multiple biological functions, and very low toxicity of lycorine imply that the agent is a potential drug candidate that warrants for further preclinical and clinic investigation.
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Affiliation(s)
- ZhiFei Cao
- Cyrus Tang Hematology Center, Jiangsu Institute of Hematology, The First Affiliated Hospital of Soochow University; Key Laboratory of Thrombosis and Hemostasis, Ministry of Health, Soochow University, Suzhou, 215006 China
| | - Ping Yang
- Cyrus Tang Hematology Center, Jiangsu Institute of Hematology, The First Affiliated Hospital of Soochow University; Key Laboratory of Thrombosis and Hemostasis, Ministry of Health, Soochow University, Suzhou, 215006 China
| | - QuanSheng Zhou
- Cyrus Tang Hematology Center, Jiangsu Institute of Hematology, The First Affiliated Hospital of Soochow University; Key Laboratory of Thrombosis and Hemostasis, Ministry of Health, Soochow University, Suzhou, 215006 China
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20
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Conklin PL, DePaolo D, Wintle B, Schatz C, Buckenmeyer G. Identification of Arabidopsis VTC3 as a putative and unique dual function protein kinase::protein phosphatase involved in the regulation of the ascorbic acid pool in plants. JOURNAL OF EXPERIMENTAL BOTANY 2013; 64:2793-804. [PMID: 23749562 DOI: 10.1093/jxb/ert140] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Ascorbic acid (AsA) is present at high levels in plants and is a potent antioxidant and cellular reductant. The major plant AsA biosynthetic pathway is through the intermediates D-mannose and L-galactose. Although there is ample evidence that plants respond to fluctuating environmental conditions with changes in the pool size of AsA, it is unclear how this regulation occurs. The AsA-deficient Arabidopsis thaliana mutants vtc3-1 and vtc3-2 define a locus that has been identified by positional cloning as At2g40860. Confirmation of this identification was through the study of AsA-deficient At2g40860 insertion mutants and by transgenic complementation of the AsA deficiency in vtc3-1 and vtc3-2 with wild-type At2g40860 cDNA. The very unusual VTC3 gene is predicted to encode a novel polypeptide with an N-terminal protein kinase domain tethered covalently to a C-terminal protein phosphatase type 2C domain. Homologues of this gene exist only within the Viridiplantae/Chloroplastida and the gene may therefore have arisen along with the D-mannose/L-galactose AsA biosynthetic pathway. The vtc3 mutant plants are defective in the ability to elevate the AsA pool in response to light and heat, suggestive of an important role for VTC3 in the regulation of the AsA pool size.
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Affiliation(s)
- Patricia L Conklin
- Biological Sciences Department, State University of New York at Cortland, Bowers Hall, Cortland, NY 13045, USA.
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21
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Wang J, Yu Y, Zhang Z, Quan R, Zhang H, Ma L, Deng XW, Huang R. Arabidopsis CSN5B interacts with VTC1 and modulates ascorbic acid synthesis. THE PLANT CELL 2013; 25:625-36. [PMID: 23424245 PMCID: PMC3608782 DOI: 10.1105/tpc.112.106880] [Citation(s) in RCA: 92] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2012] [Revised: 01/03/2013] [Accepted: 02/01/2013] [Indexed: 05/18/2023]
Abstract
Light regulates ascorbic acid (AsA) synthesis, which increases in the light, presumably reflecting a need for antioxidants to detoxify reactive molecules produced during photosynthesis. Here, we examine this regulation in Arabidopsis thaliana and find that alterations in the protein levels of the AsA biosynthetic enzyme GDP-Man pyrophosphorylase (VTC1) are associated with changes in AsA contents in light and darkness. To find regulatory factors involved in AsA synthesis, we identified VTC1-interacting proteins by yeast two-hybrid screening of a cDNA library from etiolated seedlings. This screen identified the photomorphogenic factor COP9 signalosome subunit 5B (CSN5B), which interacted with the N terminus of VTC1 in yeast and plants. Gel filtration profiling showed that VTC1-CSN5B also associated with the COP9 signalosome complex, and this interaction promotes ubiquitination-dependent VTC1 degradation through the 26S proteasome pathway. Consistent with this, csn5b mutants showed very high AsA levels in both light and darkness. Also, a double mutant of csn5b with the partial loss-of-function mutant vtc1-1 contained AsA levels between those of vtc1-1 and csn5b, showing that CSN5B modulates AsA synthesis by affecting VTC1. In addition, the csn5b mutant showed higher tolerance to salt, indicating that CSN5B regulation of AsA synthesis affects the response to salt stress. Together, our data reveal a regulatory role of CSN5B in light-dark regulation of AsA synthesis.
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Affiliation(s)
- Juan Wang
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China
- National Key Facility of Crop Gene Resources and Genetic Improvement, Beijing 100081, China
| | - Yanwen Yu
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China
- National Key Facility of Crop Gene Resources and Genetic Improvement, Beijing 100081, China
| | - Zhijin Zhang
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China
- National Key Facility of Crop Gene Resources and Genetic Improvement, Beijing 100081, China
| | - Ruidang Quan
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China
- National Key Facility of Crop Gene Resources and Genetic Improvement, Beijing 100081, China
| | - Haiwen Zhang
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China
- National Key Facility of Crop Gene Resources and Genetic Improvement, Beijing 100081, China
| | - Ligeng Ma
- College of Life Sciences, Capital Normal University, Beijing 100048, China
| | - Xing Wang Deng
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, Connecticut 06520-8104
| | - Rongfeng Huang
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China
- National Key Facility of Crop Gene Resources and Genetic Improvement, Beijing 100081, China
- Address correspondence to
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Zhang Y. Enzymes Involved in Ascorbate Biosynthesis and Metabolism in Plants. ASCORBIC ACID IN PLANTS 2013. [DOI: 10.1007/978-1-4614-4127-4_7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Cruz-Rus E, Amaya I, Valpuesta V. The challenge of increasing vitamin C content in plant foods. Biotechnol J 2012; 7:1110-21. [DOI: 10.1002/biot.201200041] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2012] [Revised: 07/04/2012] [Accepted: 07/10/2012] [Indexed: 12/15/2022]
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Schertl P, Sunderhaus S, Klodmann J, Grozeff GEG, Bartoli CG, Braun HP. L-galactono-1,4-lactone dehydrogenase (GLDH) forms part of three subcomplexes of mitochondrial complex I in Arabidopsis thaliana. J Biol Chem 2012; 287:14412-9. [PMID: 22378782 DOI: 10.1074/jbc.m111.305144] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
L-galactono-1,4-lactone dehydrogenase (GLDH) catalyzes the terminal step of the Smirnoff-Wheeler pathway for vitamin C (l-ascorbate) biosynthesis in plants. A GLDH in gel activity assay was developed to biochemically investigate GLDH localization in plant mitochondria. It previously has been shown that GLDH forms part of an 850-kDa complex that represents a minor form of the respiratory NADH dehydrogenase complex (complex I). Because accumulation of complex I is disturbed in the absence of GLDH, a role of this enzyme in complex I assembly has been proposed. Here we report that GLDH is associated with two further protein complexes. Using native gel electrophoresis procedures in combination with the in gel GLDH activity assay and immunoblotting, two mitochondrial complexes of 470 and 420 kDa were identified. Both complexes are of very low abundance. Protein identifications by mass spectrometry revealed that they include subunits of complex I. Finally, the 850-kDa complex was further investigated and shown to include the complete "peripheral arm" of complex I. GLDH is attached to a membrane domain, which represents a major fragment of the "membrane arm" of complex I. Taken together, our data further support a role of GLDH during complex I formation, which is based on its binding to specific assembly intermediates.
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Affiliation(s)
- Peter Schertl
- Institut für Pflanzengenetik, Abteilung Pflanzenproteomik, Universität Hannover, Herrenhäuser Str. 2, 30419 Hannover, Germany
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Cruz-Rus E, Amaya I, Sánchez-Sevilla JF, Botella MA, Valpuesta V. Regulation of L-ascorbic acid content in strawberry fruits. JOURNAL OF EXPERIMENTAL BOTANY 2011; 62:4191-201. [PMID: 21561953 PMCID: PMC3153677 DOI: 10.1093/jxb/err122] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2011] [Revised: 03/15/2011] [Accepted: 03/18/2011] [Indexed: 05/18/2023]
Abstract
Plants have several L-ascorbic acid (AsA) biosynthetic pathways, but the contribution of each one to the synthesis of AsA varyies between different species, organs, and developmental stages. Strawberry (Fragaria×ananassa) fruits are rich in AsA. The pathway that uses D-galacturonate as the initial substrate is functional in ripe fruits, but the contribution of other pathways to AsA biosynthesis has not been studied. The transcription of genes encoding biosynthetic enzymes such as D-galacturonate reductase (FaGalUR) and myo-inositol oxygenase (FaMIOX), and the AsA recycling enzyme monodehydroascorbate reductase (FaMDHAR) were positively correlated with the increase in AsA during fruit ripening. Fruit storage for 72 h in a cold room reduced the AsA content by 30%. Under an ozone atmosphere, this reduction was 15%. Ozone treatment increased the expression of the FaGalUR, FaMIOX, and L-galactose-1-phosphate phosphatase (FaGIPP) genes, and transcription of the L-galactono-1,4-lactone dehydrogenase (FaGLDH) and FAMDHAR genes was higher in the ozone-stored than in the air-stored fruits. Analysis of AsA content in a segregating population from two strawberry cultivars showed high variability, which did not correlate with the transcription of any of the genes studied. Study of GalUR protein in diverse cultivars of strawberry and different Fragaria species showed that a correlation between GalUR and AsA content was apparent in most cases, but it was not general. Three alleles were identified in strawberry, but any sequence effect on the AsA variability was eliminated by analysis of the allele-specific expression. Taken together, these results indicate that FaGalUR shares the control of AsA levels with other enzymes and regulatory elements in strawberry fruit.
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Affiliation(s)
- Eduardo Cruz-Rus
- Instituto de Hortofruticultura Subtropical y Mediterránea, Universidad de Málaga-Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Departamento de Biología Molecular y Bioquímica, Facultad de Ciencias, Universidad de Málaga, Campus de Teatinos s/n, E-29071 Málaga, Spain
| | - Iraida Amaya
- Área de Mejora y Biotecnología IFAPA-CIFA Málaga, Laboratorio de Bioquímica, Cortijo de la Cruz, E-29140 Málaga, Spain
| | - José F. Sánchez-Sevilla
- Área de Mejora y Biotecnología IFAPA-CIFA Málaga, Laboratorio de Bioquímica, Cortijo de la Cruz, E-29140 Málaga, Spain
| | - Miguel A. Botella
- Instituto de Hortofruticultura Subtropical y Mediterránea, Universidad de Málaga-Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Departamento de Biología Molecular y Bioquímica, Facultad de Ciencias, Universidad de Málaga, Campus de Teatinos s/n, E-29071 Málaga, Spain
| | - Victoriano Valpuesta
- Instituto de Hortofruticultura Subtropical y Mediterránea, Universidad de Málaga-Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Departamento de Biología Molecular y Bioquímica, Facultad de Ciencias, Universidad de Málaga, Campus de Teatinos s/n, E-29071 Málaga, Spain
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Cruz-Rus E, Botella MA, Valpuesta V, Gomez-Jimenez MC. Analysis of genes involved in L-ascorbic acid biosynthesis during growth and ripening of grape berries. JOURNAL OF PLANT PHYSIOLOGY 2010; 167:739-48. [PMID: 20189680 DOI: 10.1016/j.jplph.2009.12.017] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2009] [Revised: 12/07/2009] [Accepted: 12/07/2009] [Indexed: 05/06/2023]
Abstract
Recent data indicate the existence of at least three L-ascorbic acid (AsA) biosynthetic pathways in plant cells. Studying their occurrence in different plant organs and species may help to decipher the precise role(s) of AsA in plant cell physiology. In grape berries, AsA is of particular importance since it is known to be the precursor of tartaric acid, an essential component of the grape fruit. The concentration of AsA increases during development of the fruit to reach a maximum at the full ripe stage. We followed the expression of genes related to the various AsA biosynthetic pathways in this plant organ during fruit ontogeny by real time RT-PCR. Among them, a gene (VvGalUR), showing high homology to one from strawberry encoding a D-galacturonate reductase, was up-regulated during fruit ripening in parallel to the AsA content increase. Cloning of the corresponding full length cDNA showed highest similarity to the strawberry gene (FaGalUR). Moreover, VvGalUR gene expression in grape was also up-regulated by high light, a condition that increased AsA content in grape fruits, while none of the genes involved in the other possible biosynthetic pathways analyzed increased their transcript levels. The results are discussed in relation to the presence of several AsA biosynthetic pathways in grape fruits.
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Affiliation(s)
- Eduardo Cruz-Rus
- Departamento de Biología Molecular y Bioquímica, Facultad de Ciencias, Universidad de Málaga, Málaga, Spain
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Zhang W, Lorence A, Gruszewski HA, Chevone BI, Nessler CL. AMR1, an Arabidopsis gene that coordinately and negatively regulates the mannose/l-galactose ascorbic acid biosynthetic pathway. PLANT PHYSIOLOGY 2009; 150:942-50. [PMID: 19395407 PMCID: PMC2689990 DOI: 10.1104/pp.109.138453] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2009] [Accepted: 04/21/2009] [Indexed: 05/18/2023]
Abstract
Ascorbic acid (AsA) biosynthesis in plants occurs through a complex, interconnected network with mannose (Man), myoinositol, and galacturonic acid as principal entry points. Regulation within and between pathways in the network is largely uncharacterized. A gene that regulates the Man/l-galactose (l-Gal) AsA pathway, AMR1 (for ascorbic acid mannose pathway regulator 1), was identified in an activation-tagged Arabidopsis (Arabidopsis thaliana) ozone-sensitive mutant that had 60% less leaf AsA than wild-type plants. In contrast, two independent T-DNA knockout lines disrupting AMR1 accumulated 2- to 3-fold greater foliar AsA and were more ozone tolerant than wild-type controls. Real-time reverse transcription-polymerase chain reaction analysis of steady-state transcripts of genes involved in AsA biosynthesis showed that AMR1 negatively affected the expression of GDP-Man pyrophosphorylase, GDP-l-Gal phosphorylase, l-Gal-1-phosphate phosphatase, GDP-Man-3',5'-epimerase, l-Gal dehydrogenase, and l-galactono-1,4-lactone dehydrogenase, early and late enzymes of the Man/l-Gal pathway to AsA. AMR1 expression appears to be developmentally and environmentally controlled. As leaves aged, AMR1 transcripts accumulated with a concomitant decrease in AsA. AMR1 transcripts also decreased with increased light intensity. Thus, AMR1 appears to play an important role in modulating AsA levels in Arabidopsis by regulating the expression of major pathway genes in response to developmental and environmental cues.
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Affiliation(s)
- Wenyan Zhang
- Department of Plant Pathology, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061, USA
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Badejo AA, Fujikawa Y, Esaka M. Gene expression of ascorbic acid biosynthesis related enzymes of the Smirnoff-Wheeler pathway in acerola (Malpighia glabra). JOURNAL OF PLANT PHYSIOLOGY 2009; 166:652-60. [PMID: 18952318 DOI: 10.1016/j.jplph.2008.09.004] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2008] [Revised: 09/04/2008] [Accepted: 09/04/2008] [Indexed: 05/24/2023]
Abstract
The Smirnoff-Wheeler (SW) pathway has been proven to be the only significant source of l-ascorbic acid (AsA; vitamin C) in the seedlings of the model plant Arabidopsis thaliana. It is yet uncertain whether the same pathway holds for all other plants and their various organs as AsA may also be synthesized through alternative pathways. In this study, we have cloned some of the genes involved in the SW-pathway from acerola (Malpighia glabra), a plant containing enormous amount of AsA, and examined the expression patterns of these genes in the plant. The AsA contents of acerola leaves were about 8-fold more than that of Arabidopsis with 5-700-fold higher mRNA abundance in AsA-biosynthesizing genes. The unripe fruits have the highest AsA content but the accumulation was substantially repressed as the fruit transitions to maturation. The mRNAs encoding these genes showed correlation in their expression with the AsA contents of the fruits. Although very little AsA was recorded in the seeds the mRNAs encoding all the genes, with the exception of the mitochondrially located L-galactono-1,4-lactone dehydrogenase, were clearly detected in the seeds of the unripe fruits. In young leaves of acerola, the expression of most genes were repressed by the dark and induced by light. However, the expression of GDP-D-mannose pyrophosphorylase similar to that encoded by A. thaliana VTC1 was induced in the dark. The expressions of all the genes surged after 24h following wounding stress on the young leaves. These findings will advance the investigation into the molecular factors regulating the biosynthesis of abundant AsA in acerola.
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Affiliation(s)
- Adebanjo A Badejo
- Graduate School of Biosphere Sciences, Hiroshima University, Higashi-Hiroshima, Hiroshima, Japan
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Leferink NGH, Heuts DPHM, Fraaije MW, van Berkel WJH. The growing VAO flavoprotein family. Arch Biochem Biophys 2008; 474:292-301. [PMID: 18280246 DOI: 10.1016/j.abb.2008.01.027] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2007] [Revised: 01/28/2008] [Accepted: 01/30/2008] [Indexed: 11/17/2022]
Abstract
The VAO flavoprotein family is a rapidly growing family of oxidoreductases that favor the covalent binding of the FAD cofactor. In this review we report on the catalytic properties of some newly discovered VAO family members and their mode of flavin binding. Covalent binding of the flavin is a self-catalytic post-translational modification primarily taking place in oxidases. Covalent flavinylation increases the redox potential of the cofactor and thus its oxidation power. Recent findings have revealed that some members of the VAO family anchor the flavin via a dual covalent linkage (6-S-cysteinyl-8alpha-N1-histidyl FAD). Some VAO-type aldonolactone oxidoreductases favor the non-covalent binding of the flavin cofactor. These enzymes act as dehydrogenases, using cytochrome c as electron acceptor.
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Affiliation(s)
- Nicole G H Leferink
- Laboratory of Biochemistry, Wageningen University, Dreijenlaan 3, 6703 HA Wageningen, The Netherlands
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Leferink NGH, van den Berg WAM, van Berkel WJH. l-Galactono-gamma-lactone dehydrogenase from Arabidopsis thaliana, a flavoprotein involved in vitamin C biosynthesis. FEBS J 2008; 275:713-26. [PMID: 18190525 DOI: 10.1111/j.1742-4658.2007.06233.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
l-Galactono-1,4-lactone dehydrogenase (GALDH; ferricytochrome c oxidoreductase; EC 1.3.2.3) is a mitochondrial flavoenzyme that catalyzes the final step in the biosynthesis of vitamin C (l-ascorbic acid) in plants. In the present study, we report on the biochemical properties of recombinant Arabidopsis thaliana GALDH (AtGALDH). AtGALDH oxidizes, in addition to l-galactono-1,4-lactone (K(m) = 0.17 mm, k(cat) = 134 s(-1)), l-gulono-1,4-lactone (K(m) = 13.1 mm, k(cat) = 4.0 s(-1)) using cytochrome c as an electron acceptor. Aerobic reduction of AtGALDH with the lactone substrate generates the flavin hydroquinone. The two-electron reduced enzyme reacts poorly with molecular oxygen (k(ox) = 6 x 10(2) m(-1).s(-1)). Unlike most flavoprotein dehydrogenases, AtGALDH forms a flavin N5 sulfite adduct. Anaerobic photoreduction involves the transient stabilization of the anionic flavin semiquinone. Most aldonolactone oxidoreductases contain a histidyl-FAD as a covalently bound prosthetic group. AtGALDH lacks the histidine involved in covalent FAD binding, but contains a leucine instead (Leu56). Leu56 replacements did not result in covalent flavinylation but revealed the importance of Leu56 for both FAD-binding and catalysis. The Leu56 variants showed remarkable differences in Michaelis constants for both l-galactono-1,4-lactone and l-gulono-1,4-lactone and released their FAD cofactor more easily than wild-type AtGALDH. The present study provides the first biochemical characterization of AtGALDH and some active site variants. The role of GALDH and the possible involvement of other aldonolactone oxidoreductases in the biosynthesis of vitamin C in A. thaliana are also discussed.
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Signaling and Integration of Defense Functions of Tocopherol, Ascorbate and Glutathione. PHOTOPROTECTION, PHOTOINHIBITION, GENE REGULATION, AND ENVIRONMENT 2008. [DOI: 10.1007/1-4020-3579-9_16] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Hancock RD, Walker PG, Pont SDA, Marquis N, Vivera S, Gordon SL, Brennan RM, Viola R. L-Ascorbic acid accumulation in fruit of Ribes nigrum occurs by in situ biosynthesis via the L-galactose pathway. FUNCTIONAL PLANT BIOLOGY : FPB 2008; 34:1080-1091. [PMID: 32689438 DOI: 10.1071/fp07221] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2007] [Accepted: 10/22/2007] [Indexed: 06/11/2023]
Abstract
Blackcurrant (Ribes nigrum L.) is a widely grown commercial crop valued for its high vitamin C (l-ascorbic acid, AsA) content. In the present study, a systematic analysis of the mechanism of fruit AsA accumulation was undertaken. AsA accumulation occurred during fruit expansion and was associated with high in situ biosynthetic capacity via the l-galactose pathway and low rates of turnover. Cessation of AsA accumulation was associated with reduced biosynthesis and increased turnover. Translocation of AsA from photosynthetic or vegetative tissues contributed little to fruit AsA accumulation. Manipulation of substrate availability by defoliation had no effect on fruit AsA concentration but significantly reduced fruit yields. Supply of the AsA precursor l-galactono-1,4-lactone to intact, attached fruit transiently increased fruit AsA concentration which rapidly returned to control levels after removal of the compound. These data suggest strong developmental, metabolic and genetic control of AsA accumulation in blackcurrant fruit and indicate the potential for breeding high AsA cultivars.
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Affiliation(s)
- Robert D Hancock
- Scottish Crop Research Institute, Invergowrie, Dundee DD2 5DA, United Kingdom
| | - Paul G Walker
- Scottish Crop Research Institute, Invergowrie, Dundee DD2 5DA, United Kingdom
| | - Simon D A Pont
- Scottish Crop Research Institute, Invergowrie, Dundee DD2 5DA, United Kingdom
| | - Nicola Marquis
- Scottish Crop Research Institute, Invergowrie, Dundee DD2 5DA, United Kingdom
| | - Sebastian Vivera
- Scottish Crop Research Institute, Invergowrie, Dundee DD2 5DA, United Kingdom
| | - Sandra L Gordon
- Scottish Crop Research Institute, Invergowrie, Dundee DD2 5DA, United Kingdom
| | - Rex M Brennan
- Scottish Crop Research Institute, Invergowrie, Dundee DD2 5DA, United Kingdom
| | - Roberto Viola
- IASMA, Via E. Mach, S. Michele all'Adige, I-38010, Trento, Italy
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Badejo AA, Jeong ST, Goto-Yamamoto N, Esaka M. Cloning and expression of GDP-D-mannose pyrophosphorylase gene and ascorbic acid content of acerola (Malpighia glabra L.) fruit at ripening stages. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2007; 45:665-72. [PMID: 17764967 DOI: 10.1016/j.plaphy.2007.07.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2006] [Accepted: 07/17/2007] [Indexed: 05/09/2023]
Abstract
Acerola (Malpighia glabra L.) is one of the richest natural sources of L-ascorbic acid (AsA; vitamin C). GDP-D-mannose pyrophosphorylase (GMP; EC 2.7.7.13) was found to play a major role in the proposed AsA biosynthetic pathway in plants, considering that Arabidopsis vtc1-1 mutant with point mutation in this gene has a highly reduced AsA content. GMP cDNA was isolated from acerola fruits, designated MgGMP, using rapid amplification of cDNA ends (RACE), and its expression was monitored during fruit ripening. The full-length cDNA was found to have an ORF of 1083bp encoding a polypeptide of 361 amino acids. In silico analysis of the predicted amino acid sequence showed a pI of 6.45 and molecular mass of 39.7kD. MgGMP showed over 80% amino acid sequence identity with other plant GMP homologues. The phylogenetic tree shows the close relation of MgGMP to the GMP of other plants as against those from parasite, yeasts and mammals. Southern analysis indicated that M. glabra contains not less than two copies of GMP genes. Northern blot analysis showed the transcript abundance of MgGMP in all the organs of acerola examined, with the fruit having the highest expression. The relative transcript abundance of MgGMP mRNA levels in the fruits changes as the ripening process progresses, with the unripe green fruits having the highest relative mRNA level, and the lowest was found in the fruits at advanced ripening stage. A strong correlation was also observed between the relative MgGMP mRNA levels and the AsA contents of acerola during fruit ripening.
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Affiliation(s)
- Adebanjo A Badejo
- Graduate School of Biosphere Sciences, Hiroshima University, 1-4-4 Kagamiyama, Higashi-Hiroshima 739-8528, Japan
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Laing WA, Wright MA, Cooney J, Bulley SM. The missing step of the L-galactose pathway of ascorbate biosynthesis in plants, an L-galactose guanyltransferase, increases leaf ascorbate content. Proc Natl Acad Sci U S A 2007; 104:9534-9. [PMID: 17485667 PMCID: PMC1866185 DOI: 10.1073/pnas.0701625104] [Citation(s) in RCA: 152] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2007] [Indexed: 11/18/2022] Open
Abstract
The gene for one postulated enzyme that converts GDP-L-galactose to L-galactose-1-phosphate is unknown in the L-galactose pathway of ascorbic acid biosynthesis and a possible candidate identified through map-based cloning is the uncharacterized gene At4g26850. We identified a putative function for At4g26850 using PSI-Blast and motif searching to show it was a member of the histidine triad superfamily, which includes D-galactose uridyltransferase. We cloned and expressed this Arabidopsis gene and the homologous gene from Actinidia chinensis in Escherichia coli and assayed the expressed protein for activities related to converting GDP-L-galactose to L-galactose-1-P. The expressed protein is best described as a GDP-L-galactose-hexose-1-phosphate guanyltransferase (EC 2.7.7.), catalyzing the transfer of GMP from GDP-l-galactose to a hexose-1-P, most likely D-mannose-1-phosphate in vivo. Transient expression of this A. chinensis gene in tobacco leaves resulted in a >3-fold increase in leaf ascorbate as well as a 50-fold increase in GDP-L-galactose-D-mannose-1-phosphate guanyltransferase activity.
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Affiliation(s)
- William A Laing
- Horticultural and Food Research Institute of New Zealand, PB 92160, Auckland 1142, New Zealand.
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Yabuta Y, Mieda T, Rapolu M, Nakamura A, Motoki T, Maruta T, Yoshimura K, Ishikawa T, Shigeoka S. Light regulation of ascorbate biosynthesis is dependent on the photosynthetic electron transport chain but independent of sugars in Arabidopsis. JOURNAL OF EXPERIMENTAL BOTANY 2007; 58:2661-71. [PMID: 17586607 DOI: 10.1093/jxb/erm124] [Citation(s) in RCA: 139] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
It has been known that leaves exposed to high light contain more L-ascorbic acid (AsA) than those in the shade. However, the mechanism of the light regulation of the AsA pool size in plants is largely unknown. In this work, the relationship between gene expression levels related to AsA biosynthesis and photosynthesis have been studied. When 2-week-old Arabidopsis plants grown under a 16 h daily photoperiod were moved into the dark, the AsA level in the leaves was decreased by 91% in 72 h, whereas it increased by 171% in the leaves of plants exposed to continuous light during the same period. Among the several enzymes of the AsA biosynthesis pathway, the transcript levels of GDP-D-mannose pyrophosphorylase, L-galactose 1-P phosphatase, L-galactono-1,4-lactone dehydrogenase, and the VTC2 gene were down-regulated in the dark. Treatment with inhibitors of photosynthesis, 3-(3,4-dichlorophenyl)-1,1-dimethylurea and atrazine, arrested a rise in the AsA pool size accompanying the decrease in the transcript levels of the genes of the above enzyme in the leaves. When the plants were transferred to a medium containing 0.5% (w/v) sucrose, the photosynthesis activities and the leaf AsA levels were lowered even under exposure to light compared with those in plants on the medium without sucrose. In contrast, the AsA level in leaves of the sugar-insensitive Arabidopsis mutant abi4/sun6 was unaffected by external sucrose. No significant difference in the expression profiles for AsA biosynthesis enzymes was observed between the wild-type and mutant plants by sucrose feeding. The results suggest that photosynthetic electron transport of chloroplasts is closely related to AsA pool size regulation in leaves.
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Affiliation(s)
- Yukinori Yabuta
- Department of Advanced Bioscience, Faculty of Agriculture, Kinki University, 3327-204 Nakamachi, Nara, Japan
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Wolucka BA, Communi D. Mycobacterium tuberculosispossesses a functional enzyme for the synthesis of vitamin C,L-gulono-1,4-lactone dehydrogenase. FEBS J 2006; 273:4435-45. [PMID: 16956367 DOI: 10.1111/j.1742-4658.2006.05443.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The last step of the biosynthesis of L-ascorbic acid (vitamin C) in plants and animals is catalyzed by L-gulono-1,4-lactone oxidoreductases, which use both L-gulono-1,4-lactone and L-galactono-1,4-lactone as substrates. L-gulono-1,4-lactone oxidase is missing in scurvy-prone, vitamin C-deficient animals, such as humans and guinea pigs, which are also highly susceptible to tuberculosis. A blast search using the rat L-gulono-1,4-lactone oxidase sequence revealed the presence of closely related orthologs in a limited number of bacterial species, including several pathogens of human lungs, such as Mycobacterium tuberculosis, Pseudomonas aeruginosa, Burkholderia cepacia and Bacillus anthracis. The genome of M. tuberculosis, the etiologic agent of tuberculosis, encodes a protein (Rv1771) that shows 32% identity with the rat L-gulono-1,4-lactone oxidase protein. The Rv1771 gene was cloned and expressed in Escherichia coli, and the corresponding protein was affinity-purified and characterized. The FAD-binding motif-containing Rv1771 protein is a metalloenzyme that oxidizes L-gulono-1,4-lactone (Km 5.5 mm) but not L-galactono-1,4-lactone. The enzyme has a dehydrogenase activity and can use both cytochrome c (Km 4.7 microm) and phenazine methosulfate as exogenous electron acceptors. Molecular oxygen does not serve as a substrate for the Rv1771 protein. Dehydrogenase activity was measured in cellular extracts of a Mycobacterium bovis BCG strain. In conclusion, M. tuberculosis produces a novel, highly specific L-gulono-1,4-lactone dehydrogenase (Rv1771) and has the capacity to synthesize vitamin C.
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Affiliation(s)
- Beata A Wolucka
- Laboratory of Mycobacterial Biochemistry, Pasteur Institute of Brussels, Institute of Public Health, Belgium.
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Bastida J, Lavilla R, Viladomat F. Chemical and biological aspects of Narcissus alkaloids. THE ALKALOIDS. CHEMISTRY AND BIOLOGY 2006; 63:87-179. [PMID: 17133715 PMCID: PMC7118783 DOI: 10.1016/s1099-4831(06)63003-4] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
This chapter discusses the chemical and biological aspects of Narcissus alkaloids. Numerous alkaloids have been isolated from Narcissus speciesasaresult of the continuing search for novel alkaloids with pharmacological activity in the Amaryllidaceae family. The alkaloids isolated from this genus, classified in relation to the different skeleton types. The different Narcissus wild species and intersectional hybrids, grouped into subgenera and sections, with their corresponding alkaloids, arranged according to their ring system are listed. The biosynthetic pathways of Narcissus alkaloids includes: (1) enzymatic preparation of the precursors, (2) primary cyclization mechanisms, (3) enzymatic preparation of intermediates, (4) secondary cyclization, diversification, and restructuring. The chapter discusses proton nuclear magnetic resonance (1H NMR), carbon nuclear magnetic resonance (13C NMR), and mass spectrometry (MS) for Narcissus alkaloids. A list of the different Narcissus alkaloids, their spectroscopic properties, and literature with the most recent spectroscopic data is given. Several Narcissus extracts shows the following activities: antiviral, prophage induction, antibacterial, antifungal, antimalarial, insecticidal, cytotoxic, antitumor, antimitotic, antiplatelet, hypotensive, emetic, acetylcholine esterase inhibitory, antifertility, antinociceptive, chronotropic, pheromone, plant growth inhibitor, and allelopathic.
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Affiliation(s)
- Jaume Bastida
- Departament de Productes Naturals, Facultat de Farmàcia, Universitat de Barcelona, 08028 Barcelona, Spain
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Major LL, Wolucka BA, Naismith JH. Structure and function of GDP-mannose-3',5'-epimerase: an enzyme which performs three chemical reactions at the same active site. J Am Chem Soc 2005; 127:18309-20. [PMID: 16366586 PMCID: PMC3315049 DOI: 10.1021/ja056490i] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
GDP-mannose-3',5'-epimerase (GME) from Arabidopsis thaliana catalyzes the epimerization of both the 3' and 5' positions of GDP-alpha-D-mannose to yield GDP-beta-L-galactose. Production of the C5' epimer of GDP-alpha-D-mannose, GDP-beta-L-gulose, has also been reported. The reaction occurs as part of vitamin C biosynthesis in plants. We have determined structures of complexes of GME with GDP-alpha-D-mannose, GDP-beta-L-galactose, and a mixture of GDP-beta-L-gulose with GDP-beta-L-4-keto-gulose to resolutions varying from 2.0 to 1.4 A. The enzyme has the classical extended short-chain dehydratase/reductase (SDR) fold. We have confirmed that GME establishes an equilibrium between two products, GDP-beta-L-galactose and GDP-beta-L-gulose. The reaction proceeds by C4' oxidation of GDP-alpha-D-mannose followed by epimerization of the C5' position to give GDP-beta-L-4-keto-gulose. This intermediate is either reduced to give GDP-beta-L-gulose or the C3' position is epimerized to give GDP-beta-L-4-keto-galactose, then C4' is reduced to GDP-beta-L-galactose. The combination of oxidation, epimerization, and reduction in a single active site is unusual. Structural analysis coupled to site-directed mutagenesis suggests C145 and K217 as the acid/base pair responsible for both epimerizations. On the basis of the structure of the GDP-beta-L-gulose/GDP-beta-L-4-keto-gulose co-complex, we predict that a ring flip occurs during the first epimerization and that a boat intermediate is likely for the second epimerization. Comparison of GME with other SDR enzymes known to abstract a protein alpha to the keto function of a carbohydrate identifies key common features.
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Affiliation(s)
- Louise L Major
- Centre for Biomolecular Sciences, University of St. Andrews, North Haugh, St. Andrews, Fife, Scotland KY16 9ST, United Kingdom
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Guo Z, Tan H, Zhu Z, Lu S, Zhou B. Effect of intermediates on ascorbic acid and oxalate biosynthesis of rice and in relation to its stress resistance. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2005; 43:955-62. [PMID: 16310370 DOI: 10.1016/j.plaphy.2005.08.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2004] [Revised: 05/10/2005] [Accepted: 08/13/2005] [Indexed: 05/04/2023]
Abstract
Rice (Oryza sativa L.) roots were fed with L-ascorbic acid (AsA) and its putative precursors to observe AsA and oxalate concentrations and the resistance of rice to chilling, water stress, and Al toxicity. AsA concentration was significantly enhanced in both shoots and roots of rice seedlings by feeding with D-glucose or L-galactono-gamma-lactone. AsA or L-galactono-gamma-lactone treatment increased accumulation of oxalate mainly in soluble form, while these treatments decreased electrolyte leakage from root cells, H2O2 and lipid peroxidation level in rice seedlings subjected to chilling, water stress, and Al toxicity. They also alleviated the inhibition on root growth by Al. These results indicated that AsA and its immediate precursor protected plants against the oxidative damages induced by various stresses. However, 0.5 mM AsA and 10 mM L-galactono-gamma-lactone treatment had no significant effect on superoxide dismutase and catalase activity and ascorbate-peroxidase activities. Enhanced Al resistance caused by AsA and L-galactono-gamma-lactone may possibly be resulted from increased level of oxalate, which acts as metal chelator. Thus it is proposed that manipulation of AsA and oxalate biosynthesis through enhancement of L-galactono-gamma-lactone level in plants could be a strategy for improving abiotic stress tolerance.
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Affiliation(s)
- Zhenfei Guo
- Biotechnology Laboratory for Turfgrass and Forages, College of Life Science, South China Agricultural University, Guangzhou 510642, China.
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40
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Wolucka BA, Goossens A, Inzé D. Methyl jasmonate stimulates the de novo biosynthesis of vitamin C in plant cell suspensions. JOURNAL OF EXPERIMENTAL BOTANY 2005; 56:2527-38. [PMID: 16061506 DOI: 10.1093/jxb/eri246] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Vitamin C (L-ascorbic acid) is an important primary metabolite of plants that functions as an antioxidant, an enzyme cofactor, and a cell-signalling modulator in a wide array of crucial physiological processes, including biosynthesis of the cell wall, secondary metabolites and phytohormones, stress resistance, photoprotection, cell division, and growth. Plants synthesize ascorbic acid via de novo and salvage pathways, but the regulation of its biosynthesis and the mechanisms behind ascorbate homeostasis are largely unknown. Jasmonic acid and its methyl ester (jasmonates) mediate plant responses to many biotic and abiotic stresses by triggering a transcriptional reprogramming that allows cells to cope with pathogens and stress. By using 14C-mannose radiolabelling combined with HPLC and transcript profiling analysis, it is shown that methyl jasmonate treatment increases the de novo synthesis of ascorbic acid in Arabidopsis and tobacco Bright Yellow-2 (BY-2) suspension cells. In BY-2 cells, this stimulation coincides with enhanced transcription of at least two late methyl jasmonate-responsive genes encoding enzymes for vitamin C biosynthesis: the GDP-mannose 3'',5''-epimerase and a putative L-gulono-1,4-lactone dehydrogenase/oxidase. As far as is known, this is the first report of a hormonal regulation of vitamin C biosynthesis in plants. Finally, the role of ascorbic acid in jasmonate-regulated stress responses is reviewed.
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Affiliation(s)
- Beata A Wolucka
- Pasteur Institute of Brussels, Engeland Street 642, B-1180 Brussels, Belgium.
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Wilkinson SR, Prathalingam SR, Taylor MC, Horn D, Kelly JM. Vitamin C biosynthesis in trypanosomes: a role for the glycosome. Proc Natl Acad Sci U S A 2005; 102:11645-50. [PMID: 16087875 PMCID: PMC1187986 DOI: 10.1073/pnas.0504251102] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2005] [Indexed: 11/18/2022] Open
Abstract
The capacity to synthesize vitamin C (ascorbate) is widespread in eukaryotes but is absent from humans. The last step in the biosynthetic pathway involves the conversion of an aldonolactone substrate to ascorbate, a reaction catalyzed by members of an FAD-dependent family of oxidoreductases. Here we demonstrate that both the African trypanosome, Trypanosoma brucei, and the American trypanosome, Trypanosoma cruzi, have the capacity to synthesize vitamin C and show that this reaction occurs in a unique single-membrane organelle, the glycosome. The corresponding T. brucei flavoprotein (TbALO) obeys Michaelis-Menten kinetics and can utilize both L-galactono-gamma-lactone and D-arabinono-gamma-lactone as substrate, properties characteristic of plant and fungal enzymes. We could detect no activity toward the mammalian enzyme substrate L-gulono-gamma-lactone. TbALO null mutants (bloodstream form) were found to display a transient growth defect, a trait that was enhanced when they were cultured in medium in which the essential serum component had been pretreated with ascorbate oxidase to deplete vitamin C. It is implicit, therefore, that bloodstream-form trypanosomes also possess a capacity for ascorbate transport.
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Affiliation(s)
- Shane R Wilkinson
- Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London WC1E 7HT, United Kingdom.
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42
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Tokunaga T, Miyahara K, Tabata K, Esaka M. Generation and properties of ascorbic acid-overproducing transgenic tobacco cells expressing sense RNA for l-galactono-1,4-lactone dehydrogenase. PLANTA 2005; 220:854-63. [PMID: 15549373 DOI: 10.1007/s00425-004-1406-3] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2004] [Accepted: 09/13/2004] [Indexed: 05/24/2023]
Abstract
L-Galactono-1,4-lactone dehydrogenase (GalLDH; EC 1.3.2.3) is the last enzyme in the putative L-ascorbic acid (AsA) biosynthetic pathway of plants. Here, we show for the first time that the overexpression of GalLDH can increase AsA content in tobacco (Nicotiana tabacum L.) BY-2 cells. To see the effect, we analyzed the properties of these AsA-overproducing transgenic cell lines, especially in relation to AsA content of cells, cell division, senescence and resistance to oxidative stress. The mitotic index in AsA-overproducing cells was higher than in wild-type cells. Moreover, the browning of these cells was markedly restrained, and the proportion of dead cells was reduced, especially in the later period of culture. These AsA-overproducing cells also acquired resistance to paraquat (methyl viologen), which produces active oxygen species. These results contribute to the previous insights about AsA and raise the possibility of the generation of plants that have resistance to environmental stresses by increasing their AsA content.
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Affiliation(s)
- Takaaki Tokunaga
- Graduate School of Biosphere Sciences, Hiroshima University, Kagamiyama, 739-8528, Higashi-Hiroshima, Japan
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Salusjärvi T, Kalkkinen N, Miasnikov AN. Cloning and characterization of gluconolactone oxidase of Penicillium cyaneo-fulvum ATCC 10431 and evaluation of its use for production of D-erythorbic acid in recombinant Pichia pastoris. Appl Environ Microbiol 2004; 70:5503-10. [PMID: 15345438 PMCID: PMC520892 DOI: 10.1128/aem.70.9.5503-5510.2004] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2004] [Accepted: 05/08/2004] [Indexed: 11/20/2022] Open
Abstract
A D-erythorbic acid-forming soluble flavoprotein, gluconolactone oxidase (GLO), was purified from Penicillium cyaneo-fulvum strain ATCC 10431 and partially sequenced. Peptide sequences were used to isolate a cDNA clone encoding the enzyme. The cloned gene exhibits high levels of similarity with the genes encoding other known eukaryotic lactone oxidases and also with the genes encoding some putative prokaryotic lactone oxidases. Analysis of the coding sequence of the GLO gene indicated the presence of a typical secretion signal sequence at the N terminus of GLO. No other targeting or anchoring signals were found, suggesting that GLO is the first known lactone oxidase that is secreted rather than targeted to the membranes of the endoplasmic reticulum or mitochondria. Experimental evidence, including the N-terminal sequence of mature GLO and data on glycosylation and localization of the enzyme in native and recombinant hosts, supports this analysis. The GLO gene was expressed in Pichia pastoris, and recombinant GLO was produced by using the strong methanol-induced AOX1 promoter. In order to evaluate the suitability of purified GLO for production of D-erythorbic acid, we immobilized it on N-hydroxysuccinimide-activated Sepharose and found that the immobilized GLO retained full activity during immobilization but was rather unstable under reaction conditions. Our results show that both soluble and immobilized forms of GLO can, in principle, be used for production of D-erythorbic acid from D-glucono-delta-lactone or (in combination with glucose oxidase and catalase) from glucose. We also demonstrated the feasibility of glucose-D-erythorbic acid fermentation with recombinant strains coexpressing GLO and glucose oxidase genes, and we analyzed problems associated with construction of efficient D-erythorbic acid-producing hosts.
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Wolucka BA, Van Montagu M. GDP-mannose 3',5'-epimerase forms GDP-L-gulose, a putative intermediate for the de novo biosynthesis of vitamin C in plants. J Biol Chem 2003; 278:47483-90. [PMID: 12954627 DOI: 10.1074/jbc.m309135200] [Citation(s) in RCA: 238] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Despite its importance for agriculture, bioindustry, and nutrition, the fundamental process of L-ascorbic acid (vitamin C) biosynthesis in plants is not completely elucidated, and little is known about its regulation. The recently identified GDP-Man 3',5'-epimerase catalyzes a reversible epimerization of GDP-D-mannose that precedes the committed step in the biosynthesis of vitamin C, resulting in the hydrolysis of the highly energetic glycosyl-pyrophosphoryl linkage. Here, we characterize the native and recombinant GDP-Man 3',5'-epimerase of Arabidopsis thaliana. GDP and GDP-D-glucose are potent competitive inhibitors of the enzyme, whereas GDP-L-fucose gives a complex type of inhibition. The epimerase contains a modified version of the NAD binding motif and is inhibited by NAD(P)H and stimulated by NAD(P)+. A feedback inhibition of vitamin C biosynthesis is observed apparently at the level of GDP-Man 3',5'-epimerase. The epimerase catalyzes at least two distinct epimerization reactions and releases, besides the well known GDP-l-galactose, a novel intermediate: GDP-L-gulose. The yield of the epimerization varies and seems to depend on the molecular form of the enzyme. Both recombinant and native enzymes co-purified with a Hsp70 heat-shock protein (Escherichia coli DnaK and A. thaliana Hsc70.3, respectively). We speculate, therefore, that the Hsp70 molecular chaperones might be involved in folding and/or regulation of the epimerase. In summary, the plant epimerase undergoes a complex regulation and could control the carbon flux into the vitamin C pathway in response to the redox state of the cell, stress conditions, and GDP-sugar demand for the cell wall/glycoprotein biosynthesis. Exogenous L-gulose and L-gulono-1,4-lactone serve as direct precursors of l-ascorbic acid in plant cells. We propose an L-gulose pathway for the de novo biosynthesis of vitamin C in plants.
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Affiliation(s)
- Beata A Wolucka
- Department of Molecular Microbiology, Flanders Interuniversity Institute for Biotechnology (VIB), Kasteelpark Arenberg 31, B-3001 Leuven-Heverlee, Belgium.
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Tudela JA, Hernández JA, Gil MI, Espín JC. L-galactono-gamma-lactone dehydrogenase aand vitamin C content in fresh-cut potatoes stored under controlled atmospheres. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2003; 51:4296-4302. [PMID: 12848501 DOI: 10.1021/jf030071s] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
L-galactono-gamma-lactone dehydrogenase (GLDH) activity and vitamin C content as ascorbic acid (AA) plus dehydroascorbic acid (DHA) were evaluated in five potato tuber cultivars (Agata, Altesse, Franceline, Manon, and Monalisa). The effect of fresh-cutting and subsequent refrigerated storage of Manon potato under different atmospheres (air, 20% CO(2) + air, 100% N(2), and vacuum packaging) on GLDH activity and vitamin C content was also determined. GLDH from the five potato tuber cultivars showed typical inhibition kinetics by high substrate concentration in the synthesis of AA from its physiological precursor L-galactonic acid-gamma-lactone (GL). GLDH activity was not correlated with the corresponding vitamin C content in any potato tuber cultivar. GLDH from all the cultivars presented a major isoform with isoelectric point (IEP) 5, which changed to IEP = 4.3 after minimal processing. In addition, the GLDH-catalyzed synthesis of AA by the new isoform showed typical Michaelis kinetics, in which the enzyme became more efficient to catalyze the reaction. Whether the change in the isoform pattern was due to either post-translational modifications or de novo synthesis of a new isoenzyme remains unanswered. Fresh-cutting increased GLDH activity from 4.7-fold (vacuum packaging) to 11-fold (air) after 6 days. In addition, 100% of vitamin C content was retained in air and decreased in the rest of atmospheres after this storage period, following the sequence vacuum packaging (89%) > 100% N(2) (78%) > 20% CO(2) + air (63%). This tendency was correlated with the corresponding GLDH activity detected in each storage atmosphere, except in the case of 20% CO(2) + air. Vacuum packaging proved to be the best storage condition, because fresh-cut potatoes did not turn brown and retained 89% of initial vitamin C content.
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Affiliation(s)
- Juan Antonio Tudela
- Research Group on Quality, Safety, and Bioactivity of Plant Foods, Department of Food Science and Technology, CEBAS-CSIC. P.O. Box 164.30100 Espinardo, Murcia, Spain
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Abstract
Over the past decade there has been increasing pressure to develop alternatives to the Reichstein process, a largely chemical synthesis by which the vast majority of world vitamin C (L-ascorbic acid, L-AA) is produced. The pressures include increasing environmental concerns and legislation, and the need to increase process efficiency and reduce capital costs. The development of efficient fermentation processes in the past ten years has also represented a catalyst for change. Here, we describe the development of biotechnological alternatives for the synthesis of Reichstein intermediates by industrial microorganisms. The recent elucidation of the plant biosynthetic pathway represents new opportunities not only for the direct synthesis of L-AA by fermentation but also for the production of human crop plants and animal fodder with enhanced nutritional value. We discuss the potential for these developments in the light of recent findings concerning L-AA biosynthesis in plants.
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Affiliation(s)
- Robert D Hancock
- Unit of Plant Biochemistry, Scottish Crop Research Institute, Invergowrie, Dundee, UK
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Wolucka BA, Persiau G, Van Doorsselaere J, Davey MW, Demol H, Vandekerckhove J, Van Montagu M, Zabeau M, Boerjan W. Partial purification and identification of GDP-mannose 3",5"-epimerase of Arabidopsis thaliana, a key enzyme of the plant vitamin C pathway. Proc Natl Acad Sci U S A 2001; 98:14843-8. [PMID: 11752432 PMCID: PMC64946 DOI: 10.1073/pnas.011578198] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The first step in the biosynthetic pathway of vitamin C in plants is the formation, at the level of sugar nucleotide, of l-galactosyl residues, catalyzed by a largely unknown GDP-d-mannose 3",5"-epimerase. By using combined conventional biochemical and mass spectrometry methods, we obtained a highly purified preparation of GDP-d-mannose 3",5"-epimerase from an Arabidopsis thaliana cell suspension. The native enzyme is an 84-kDa dimer, composed of two apparently identical subunits. In-gel tryptic digestion of the enzyme subunit, followed by peptide sequencing and a blast search, led to the identification of the epimerase gene. The closest homolog of the plant epimerase is the BlmG gene product of Streptomyces sp., a putative NDP-d-mannose 5"-epimerase. The plant GDP-d-mannose 3",5"-epimerase is, to our knowledge, a novel member of the extended short-chain dehydrogenase/reductase family. The enzyme was cloned and expressed in Escherichia coli cells.
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Affiliation(s)
- B A Wolucka
- Departments of Molecular and Plant Genetics and Biochemistry, Faculty of Medicine, Flanders Interuniversity Institute for Biotechnology (VIB), Ghent University, K.L. Ledeganckstraat 35, B-9000 Ghent, Belgium.
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48
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Wolucka BA, Davey MW, Boerjan W. A high-performance liquid chromatography radio method for determination of L-ascorbic acid and guanosine 5'-diphosphate-l-galactose, key metabolites of the plant vitamin C pathway. Anal Biochem 2001; 294:161-8. [PMID: 11444812 DOI: 10.1006/abio.2001.5165] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A simple, rapid, and quantitative high-pressure liquid chromatography radio method is described for the determination of in vivo (14)C-labeled l-ascorbate, dehydro-l-ascorbate, and total l-ascorbate of Arabidopsis thaliana cell suspensions upon incubation of cultures with exogenous d-[(14)C]mannose. The same radio-HPLC conditions can be used to follow the products of in vitro enzymatic conversions of GDP-d-mannose by enzyme extracts of A. thaliana, namely GDP-l-galactose, GDP-4"-keto,6"-deoxy-d-mannose, and GDP-l-fucose. In particular, an accurate assay for GDP-d-mannose 3",5"-epimerase, a key enzyme of the plant vitamin C pathway, is presented.
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Affiliation(s)
- B A Wolucka
- Department of Plant Genetics, Flanders Interuniversity Institute for Biotechnology (VIB), Ghent University, K.L., Ledeganckstraat 35, Gent, B-9000, Belgium.
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Tabata K, Oba K, Suzuki K, Esaka M. Generation and properties of ascorbic acid-deficient transgenic tobacco cells expressing antisense RNA for L-galactono-1,4-lactone dehydrogenase. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2001; 27:139-48. [PMID: 11489191 DOI: 10.1046/j.1365-313x.2001.01074.x] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
In higher plants, the terminal step of L-ascorbic acid (AsA) biosynthesis is catalyzed by the enzyme L-galactono-1,4-lactone dehydrogenase (EC 1.3.2.3, GalLDH). We generated AsA-deficient transgenic tobacco BY-2 cell lines by antisense expression of the GalLDH cDNA that was amplified from BY-2 cells using PCR. Two transgenic cell-lines, AS1-1 and AS2-2, having a marked expression of antisense RNA were analyzed. Antisense suppression of GalLDH mRNA led to a significant decline in the GalLDH activity. The AsA levels in the transgenic cell lines were found to be 30% lower than the wild-type BY-2 cells. In synchronous cultures, division of AS1-1 and AS2-2 cells was restrained with a concomitant decrease in mitotic index that was probably due to a decline in AsA levels. The rate of cell growth was also found to be less than that of the wild-type cells. Interestingly, there was a significant phenotypic difference between the transgenic and wild-type cells. The calli of AS1-1 and AS2-2 appeared to be sticky and soft. Back extrusion method also showed that AsA-deficient BY-2 callus was rheologically soft. Furthermore, microscopic analysis revealed that AS1-1 and AS2-2 cells were abnormally slender, suggesting a potential for a significant and a uni-axial elongation. Thus, we observed that decline in the AsA levels has an adverse effect on the division, growth and structure of a plant cell.
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Affiliation(s)
- K Tabata
- Faculty of Applied Biological Science, Hiroshima University, Kagamiyama, Higashi-Hiroshima, 739-8528 Japan
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Huh WK, Kim ST, Kim H, Jeong G, Kang SO. Deficiency of D-erythroascorbic acid attenuates hyphal growth and virulence of Candida albicans. Infect Immun 2001; 69:3939-46. [PMID: 11349062 PMCID: PMC98429 DOI: 10.1128/iai.69.6.3939-3946.2001] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In some lower eukaryotes, D-erythroascorbic acid, a five-carbon analog of L-ascorbic acid, is present instead of L-ascorbic acid. We have cloned ALO1, the gene encoding D-arabinono-1,4-lactone oxidase, which catalyzes the final step of D-erythroascorbic acid biosynthesis in Candida albicans. The ALO1 gene contained a continuous open reading frame of 1,671 bp that encodes a polypeptide consisting of 557 amino acids with a calculated molecular mass of 63,428 Da. To investigate the functional roles of D-erythroascorbic acid in C. albicans, we disrupted or overexpressed the ALO1 gene. In the alo1/alo1 null mutants, the activity of D-arabinono-1,4-lactone oxidase was completely lost and D-erythroascorbic acid could not be detected. When ALO1 on a multicopy plasmid was transformed in C. albicans, the enzyme activity and the intracellular D-erythroascorbic acid level were increased up to 3.4-fold and 4.0-fold, respectively. The alo1/alo1 null mutants of C. albicans showed increased sensitivity towards oxidative stress. Overexpression of ALO1 made the cells more resistant to the same stress. The alo1/alo1 mutants showed defective hyphal growth and attenuated virulence. Taken together, our results suggest that D-erythroascorbic acid functions as an important antioxidant and can be considered one of the virulence factors enhancing the pathogenicity of C. albicans.
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Affiliation(s)
- W K Huh
- Laboratory of Biophysics, School of Biological Sciences and Institute of Microbiology, Seoul National University, Seoul 151-742, Republic of Korea
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