1
|
Decker D, Aubert J, Wilczynska M, Kleczkowski LA. Exploring Redox Modulation of Plant UDP-Glucose Pyrophosphorylase. Int J Mol Sci 2023; 24:ijms24108914. [PMID: 37240260 DOI: 10.3390/ijms24108914] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2023] [Revised: 05/10/2023] [Accepted: 05/15/2023] [Indexed: 05/28/2023] Open
Abstract
UDP-glucose (UDPG) pyrophosphorylase (UGPase) catalyzes a reversible reaction, producing UDPG, which serves as an essential precursor for hundreds of glycosyltransferases in all organisms. In this study, activities of purified UGPases from sugarcane and barley were found to be reversibly redox modulated in vitro through oxidation by hydrogen peroxide or oxidized glutathione (GSSG) and through reduction by dithiothreitol or glutathione. Generally, while oxidative treatment decreased UGPase activity, a subsequent reduction restored the activity. The oxidized enzyme had increased Km values with substrates, especially pyrophosphate. The increased Km values were also observed, regardless of redox status, for UGPase cysteine mutants (Cys102Ser and Cys99Ser for sugarcane and barley UGPases, respectively). However, activities and substrate affinities (Kms) of sugarcane Cys102Ser mutant, but not barley Cys99Ser, were still prone to redox modulation. The data suggest that plant UGPase is subject to redox control primarily via changes in the redox status of a single cysteine. Other cysteines may also, to some extent, contribute to UGPase redox status, as seen for sugarcane enzymes. The results are discussed with respect to earlier reported details of redox modulation of eukaryotic UGPases and regarding the structure/function properties of these proteins.
Collapse
Affiliation(s)
- Daniel Decker
- Department of Plant Physiology, Umeå Plant Science Centre, Umeå University, 90187 Umeå, Sweden
| | - Juliette Aubert
- Department of Plant Physiology, Umeå Plant Science Centre, Umeå University, 90187 Umeå, Sweden
| | | | - Leszek A Kleczkowski
- Department of Plant Physiology, Umeå Plant Science Centre, Umeå University, 90187 Umeå, Sweden
| |
Collapse
|
2
|
Tojo H, Tabeta H, Gunji S, Hirai MY, David P, Javot H, Ferjani A. Roles of type II H +-PPases and PPsPase1/PECP2 in early developmental stages and PPi homeostasis of Arabidopsis thaliana. FRONTIERS IN PLANT SCIENCE 2023; 14:1031426. [PMID: 36778688 PMCID: PMC9911876 DOI: 10.3389/fpls.2023.1031426] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 01/09/2023] [Indexed: 06/18/2023]
Abstract
The regulation of intracellular pyrophosphate (PPi) level is crucial for proper morphogenesis across all taxonomic kingdoms. PPi is released as a byproduct from ~200 metabolic reactions, then hydrolyzed by either membrane-bound (H+-PPase) or soluble pyrophosphatases (PPases). In Arabidopsis, the loss of the vacuolar H+-PPase/FUGU5, a key enzyme in PPi homeostasis, results in delayed growth and a number of developmental defects, pointing to the importance of PPi homeostasis in plant morphogenesis. The Arabidopsis genome encodes several PPases in addition to FUGU5, such as PPsPase1/PECP2, VHP2;1 and VHP2;2, although their significance regarding PPi homeostasis remains elusive. Here, to assess their contribution, phenotypic analyses of cotyledon aspect ratio, palisade tissue cellular phenotypes, adaxial side pavement cell complexity, stomatal distribution, and etiolated seedling length were performed, provided that they were altered due to excess PPi in a fugu5 mutant background. Overall, our analyses revealed that the above five traits were unaffected in ppspase1/pecp2, vhp2;1 and vhp2;2 loss-of-function mutants, as well as in fugu5 mutant lines constitutively overexpressing PPsPase1/PECP2. Furthermore, metabolomics revealed that ppspase1/pecp2, vhp2;1 and vhp2;2 etiolated seedlings exhibited metabolic profiles comparable to the wild type. Together, these results indicate that the contribution of PPsPase1/PECP2, VHP2;1 and VHP2;2 to PPi levels is negligible in comparison to FUGU5 in the early stages of seedling development.
Collapse
Affiliation(s)
- Hiroshi Tojo
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan
- Department of Biology, Tokyo Gakugei University, Koganei, Tokyo, Japan
| | - Hiromitsu Tabeta
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan
- Department of Biology, Tokyo Gakugei University, Koganei, Tokyo, Japan
- RIKEN Center for Sustainable Resource Science, Yokohama, Japan
| | - Shizuka Gunji
- Department of Biology, Tokyo Gakugei University, Koganei, Tokyo, Japan
| | - Masami Y. Hirai
- RIKEN Center for Sustainable Resource Science, Yokohama, Japan
| | - Pascale David
- Aix Marseille Univ, CEA, CNRS, BIAM, Saint Paul-Lez-Durance, France
| | - Hélène Javot
- Aix Marseille Univ, CEA, CNRS, BIAM, Saint Paul-Lez-Durance, France
- Aix Marseille Univ, CEA, CNRS, BIAM, Marseille, France
| | - Ali Ferjani
- Department of Biology, Tokyo Gakugei University, Koganei, Tokyo, Japan
| |
Collapse
|
3
|
Tabeta H, Gunji S, Kawade K, Ferjani A. Leaf-size control beyond transcription factors: Compensatory mechanisms. FRONTIERS IN PLANT SCIENCE 2023; 13:1024945. [PMID: 36756231 PMCID: PMC9901582 DOI: 10.3389/fpls.2022.1024945] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Accepted: 12/28/2022] [Indexed: 06/18/2023]
Abstract
Plant leaves display abundant morphological richness yet grow to characteristic sizes and shapes. Beginning with a small number of undifferentiated founder cells, leaves evolve via a complex interplay of regulatory factors that ultimately influence cell proliferation and subsequent post-mitotic cell enlargement. During their development, a sequence of key events that shape leaves is both robustly executed spatiotemporally following a genomic molecular network and flexibly tuned by a variety of environmental stimuli. Decades of work on Arabidopsis thaliana have revisited the compensatory phenomena that might reflect a general and primary size-regulatory mechanism in leaves. This review focuses on key molecular and cellular events behind the organ-wide scale regulation of compensatory mechanisms. Lastly, emerging novel mechanisms of metabolic and hormonal regulation are discussed, based on recent advances in the field that have provided insights into, among other phenomena, leaf-size regulation.
Collapse
Affiliation(s)
- Hiromitsu Tabeta
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan
- Department of Biology, Tokyo Gakugei University, Tokyo, Japan
- RIKEN Center for Sustainable Resource Science, Yokohama, Japan
| | - Shizuka Gunji
- Department of Biology, Tokyo Gakugei University, Tokyo, Japan
| | - Kensuke Kawade
- RIKEN Center for Sustainable Resource Science, Yokohama, Japan
- National Institute for Basic Biology, Okazaki, Japan
- Department of Basic Biology, School of Life Science, Graduate University for Advanced Studies (SOKENDAI), Okazaki, Japan
| | - Ali Ferjani
- Department of Biology, Tokyo Gakugei University, Tokyo, Japan
| |
Collapse
|
4
|
Gunji S, Kawade K, Tabeta H, Horiguchi G, Oikawa A, Asaoka M, Hirai MY, Tsukaya H, Ferjani A. Tissue-targeted inorganic pyrophosphate hydrolysis in a fugu5 mutant reveals that excess inorganic pyrophosphate triggers developmental defects in a cell-autonomous manner. FRONTIERS IN PLANT SCIENCE 2022; 13:945225. [PMID: 35991393 PMCID: PMC9386291 DOI: 10.3389/fpls.2022.945225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Accepted: 06/30/2022] [Indexed: 06/15/2023]
Abstract
Excess PPi triggers developmental defects in a cell-autonomous manner. The level of inorganic pyrophosphate (PPi) must be tightly regulated in all kingdoms for the proper execution of cellular functions. In plants, the vacuolar proton pyrophosphatase (H+-PPase) has a pivotal role in PPi homeostasis. We previously demonstrated that the excess cytosolic PPi in the H+-PPase loss-of-function fugu5 mutant inhibits gluconeogenesis from seed storage lipids, arrests cell division in cotyledonary palisade tissue, and triggers a compensated cell enlargement (CCE). Moreover, PPi alters pavement cell (PC) shape, stomatal patterning, and functioning, supporting specific yet broad inhibitory effects of PPi on leaf morphogenesis. Whereas these developmental defects were totally rescued by the expression of the yeast soluble pyrophosphatase IPP1, sucrose supply alone canceled CCE in the palisade tissue but not the epidermal developmental defects. Hence, we postulated that the latter are likely triggered by excess PPi rather than a sucrose deficit. To formally test this hypothesis, we adopted a spatiotemporal approach by constructing and analyzing fugu5-1 PDF1 pro ::IPP1, fugu5-1 CLV1 pro ::IPP1, and fugu5-1 ICL pro ::IPP1, whereby PPi was removed specifically from the epidermis, palisade tissue cells, or during the 4 days following seed imbibition, respectively. It is important to note that whereas PC defects in fugu5-1 PDF1 pro ::IPP1 were completely recovered, those in fugu5-1 CLV1 pro ::IPP1 were not. In addition, phenotypic analyses of fugu5-1 ICL pro ::IPP1 lines demonstrated that the immediate removal of PPi after seed imbibition markedly improved overall plant growth, abolished CCE, but only partially restored the epidermal developmental defects. Next, the impact of spatial and temporal removal of PPi was investigated by capillary electrophoresis time-of-flight mass spectrometry (CE-TOF MS). Our analysis revealed that the metabolic profiles are differentially affected among all the above transgenic lines, and consistent with an axial role of central metabolism of gluconeogenesis in CCE. Taken together, this study provides a conceptual framework to unveil metabolic fluctuations within leaf tissues with high spatio-temporal resolution. Finally, our findings suggest that excess PPi exerts its inhibitory effect in planta in the early stages of seedling establishment in a tissue- and cell-autonomous manner.
Collapse
Affiliation(s)
- Shizuka Gunji
- Department of Biology, Tokyo Gakugei University, Koganei, Tokyo, Japan
- United Graduate School of Education, Tokyo Gakugei University, Tokyo, Japan
| | - Kensuke Kawade
- National Institute for Basic Biology, Okazaki, Aichi, Japan
- Department of Basic Biology, School of Life Sciences, Graduate University for Advanced Studies (SOKENDAI), Okazaki, Aichi, Japan
- RIKEN Center for Sustainable Resource Science, Yokohama, Japan
| | - Hiromitsu Tabeta
- Department of Biology, Tokyo Gakugei University, Koganei, Tokyo, Japan
- RIKEN Center for Sustainable Resource Science, Yokohama, Japan
| | - Gorou Horiguchi
- Department of Life Science, College of Science, Rikkyo University, Tokyo, Japan
- Research Center for Life Science, College of Science, Rikkyo University, Tokyo, Japan
| | - Akira Oikawa
- RIKEN Center for Sustainable Resource Science, Yokohama, Japan
- Faculty of Agriculture, Yamagata University, Tsuruoka, Japan
| | - Mariko Asaoka
- Department of Biology, Tokyo Gakugei University, Koganei, Tokyo, Japan
| | - Masami Yokota Hirai
- RIKEN Center for Sustainable Resource Science, Yokohama, Japan
- Department of Applied Biosciences, Graduate School of Bioagricultural Science, Nagoya University, Nagoya, Japan
| | - Hirokazu Tsukaya
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Ali Ferjani
- Department of Biology, Tokyo Gakugei University, Koganei, Tokyo, Japan
| |
Collapse
|
5
|
Effects of Magnesium, Pyrophosphate and Phosphonates on Pyrophosphorolytic Reaction of UDP-Glucose Pyrophosphorylase. PLANTS 2022; 11:plants11121611. [PMID: 35736762 PMCID: PMC9230926 DOI: 10.3390/plants11121611] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Revised: 06/05/2022] [Accepted: 06/14/2022] [Indexed: 12/03/2022]
Abstract
UDP-glucose pyrophosphorylase (UGPase) carries a freely reversible reaction, using glucose-1-P and UTP to produce UDP-glucose (UDPG) and pyrophosphate (PPi), with UDPG being essential for glycosylation reactions in all organisms including, e.g., synthesis of sucrose, cellulose and glycoproteins. In the present study, we found that free magnesium (Mg2+) had profound effects on the reverse reaction of purified barley UGPase, and was absolutely required for its activity, with an apparent Km of 0.13 mM. More detailed analyses with varied concentrations of MgPPi allowed us to conclude that it is the MgPPi complex which serves as true substrate for UGPase in its reverse reaction, with an apparent Km of 0.06 mM. Free PPi was an inhibitor in this reaction. Given the key role of PPi in the UGPase reaction, we have also tested possible effects of phosphonates, which are analogs of PPi and phosphate (Pi). Clodronate and etidronate (PPi analogs) had little or no effect on UGPase activity, whereas fosetyl-Al (Pi analog), a known fungicide, acted as effective near-competitive inhibitor versus PPi, with Ki of 0.15 mM. The data are discussed with respect to the role of magnesium in the UGPase reaction and elucidating the use of inhibitors in studies on cellular function of UGPase and related enzymes.
Collapse
|
6
|
A structural approach to understanding enzymatic regulation of chemical reaction networks. Biochem J 2022; 479:1265-1283. [PMID: 35713414 PMCID: PMC9246345 DOI: 10.1042/bcj20210545] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 05/17/2022] [Accepted: 05/19/2022] [Indexed: 12/02/2022]
Abstract
In living cells, chemical reactions are connected by sharing their products and substrates, and form complex systems, i.e. chemical reaction network. One of the largest missions in modern biology is to understand behaviors of such systems logically based on information of network structures. However, there are series of obstacles to study dynamical behaviors of complex network systems in biology. For example, network structure does not provide sufficient information to determine details of the dynamical behaviors. In this review, I will introduce a novel mathematical theory, structural sensitivity analysis, by which the responses of reaction systems upon the changes in enzyme activities/amounts are determined from network structure alone. The patterns of responses exhibit characteristic features, localization and hierarchy, depending on the topology of the network. The theory also shows that ranges of enzymatic regulations are governed by a mathematical law characterized by local topology of substructures. These findings imply that the network topology is one of the origins of biological robustness.
Collapse
|
7
|
Nakayama H, Koga H, Long Y, Hamant O, Ferjani A. Looking beyond the gene network - metabolic and mechanical cell drivers of leaf morphogenesis. J Cell Sci 2022; 135:275072. [PMID: 35438169 DOI: 10.1242/jcs.259611] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The above-ground organs in plants display a rich diversity, yet they grow to characteristic sizes and shapes. Organ morphogenesis progresses through a sequence of key events, which are robustly executed spatiotemporally as an emerging property of intrinsic molecular networks while adapting to various environmental cues. This Review focuses on the multiscale control of leaf morphogenesis. Beyond the list of known genetic determinants underlying leaf growth and shape, we focus instead on the emerging novel mechanisms of metabolic and biomechanical regulations that coordinate plant cell growth non-cell-autonomously. This reveals how metabolism and mechanics are not solely passive outcomes of genetic regulation but play instructive roles in leaf morphogenesis. Such an integrative view also extends to fluctuating environmental cues and evolutionary adaptation. This synthesis calls for a more balanced view on morphogenesis, where shapes are considered from the standpoints of geometry, genetics, energy and mechanics, and as emerging properties of the cellular expression of these different properties.
Collapse
Affiliation(s)
- Hokuto Nakayama
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 113-0033 Tokyo, Japan
| | - Hiroyuki Koga
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 113-0033 Tokyo, Japan
| | - Yuchen Long
- Department of Biological Sciences, The National University of Singapore, Singapore 117543, Singapore
| | - Olivier Hamant
- Laboratoire de Reproduction et Développement des Plantes, Université de Lyon, ENS de Lyon, UCB Lyon 1, CNRS, INRAE, 69007 Lyon, France
| | - Ali Ferjani
- Department of Biology, Tokyo Gakugei University, 184-8501 Tokyo, Japan
| |
Collapse
|
8
|
Tabeta H, Higashi Y, Okazaki Y, Toyooka K, Wakazaki M, Sato M, Saito K, Hirai MY, Ferjani A. Skotomorphogenesis exploits threonine to promote hypocotyl elongation. QUANTITATIVE PLANT BIOLOGY 2022; 3:e26. [PMID: 37077988 PMCID: PMC10095960 DOI: 10.1017/qpb.2022.19] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Revised: 09/18/2022] [Accepted: 09/20/2022] [Indexed: 05/02/2023]
Abstract
Mobilisation of seed storage reserves is important for seedling establishment in Arabidopsis. In this process, sucrose is synthesised from triacylglycerol via core metabolic processes. Mutants with defects in triacylglycerol-to-sucrose conversion display short etiolated seedlings. We found that whereas sucrose content in the indole-3-butyric acid response 10 (ibr10) mutant was significantly reduced, hypocotyl elongation in the dark was unaffected, questioning the role of IBR10 in this process. To dissect the metabolic complexity behind cell elongation, a quantitative-based phenotypic analysis combined with a multi-platform metabolomics approach was applied. We revealed that triacylglycerol and diacylglycerol breakdown were disrupted in ibr10, resulting in low sugar content and poor photosynthetic ability. Importantly, batch-learning self-organised map clustering revealed that threonine level was correlated with hypocotyl length. Consistently, exogenous threonine supply stimulated hypocotyl elongation, indicating that sucrose levels are not always correlated with etiolated seedling length, suggesting the contribution of amino acids in this process.
Collapse
Affiliation(s)
- Hiromitsu Tabeta
- Department of Biology, Tokyo Gakugei University, Tokyo, Japan
- RIKEN Center for Sustainable Resource Science, Yokohama, Japan
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan
| | | | - Yozo Okazaki
- RIKEN Center for Sustainable Resource Science, Yokohama, Japan
- Graduate School of Bioresources, Mie University, Tsu, Japan
| | | | - Mayumi Wakazaki
- RIKEN Center for Sustainable Resource Science, Yokohama, Japan
| | - Mayuko Sato
- RIKEN Center for Sustainable Resource Science, Yokohama, Japan
| | - Kazuki Saito
- RIKEN Center for Sustainable Resource Science, Yokohama, Japan
| | - Masami Y Hirai
- RIKEN Center for Sustainable Resource Science, Yokohama, Japan
| | - Ali Ferjani
- Department of Biology, Tokyo Gakugei University, Tokyo, Japan
- Author for correspondence: A. Ferjani, E-mail:
| |
Collapse
|
9
|
Tabeta H, Watanabe S, Fukuda K, Gunji S, Asaoka M, Hirai MY, Seo M, Tsukaya H, Ferjani A. An auxin signaling network translates low-sugar-state input into compensated cell enlargement in the fugu5 cotyledon. PLoS Genet 2021; 17:e1009674. [PMID: 34351899 PMCID: PMC8341479 DOI: 10.1371/journal.pgen.1009674] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Accepted: 06/18/2021] [Indexed: 01/29/2023] Open
Abstract
In plants, the effective mobilization of seed nutrient reserves is crucial during germination and for seedling establishment. The Arabidopsis H+-PPase-loss-of-function fugu5 mutants exhibit a reduced number of cells in the cotyledons. This leads to enhanced post-mitotic cell expansion, also known as compensated cell enlargement (CCE). While decreased cell numbers have been ascribed to reduced gluconeogenesis from triacylglycerol, the molecular mechanisms underlying CCE remain ill-known. Given the role of indole 3-butyric acid (IBA) in cotyledon development, and because CCE in fugu5 is specifically and completely cancelled by ech2, which shows defective IBA-to-indoleacetic acid (IAA) conversion, IBA has emerged as a potential regulator of CCE. Here, to further illuminate the regulatory role of IBA in CCE, we used a series of high-order mutants that harbored a specific defect in IBA-to-IAA conversion, IBA efflux, IAA signaling, or vacuolar type H+-ATPase (V-ATPase) activity and analyzed the genetic interaction with fugu5-1. We found that while CCE in fugu5 was promoted by IBA, defects in IBA-to-IAA conversion, IAA response, or the V-ATPase activity alone cancelled CCE. Consistently, endogenous IAA in fugu5 reached a level 2.2-fold higher than the WT in 1-week-old seedlings. Finally, the above findings were validated in icl-2, mls-2, pck1-2 and ibr10 mutants, in which CCE was triggered by low sugar contents. This provides a scenario in which following seed germination, the low-sugar-state triggers IAA synthesis, leading to CCE through the activation of the V-ATPase. These findings illustrate how fine-tuning cell and organ size regulation depend on interplays between metabolism and IAA levels in plants.
Collapse
Affiliation(s)
- Hiromitsu Tabeta
- Department of Biology, Tokyo Gakugei University, Koganei-shi, Tokyo, Japan
- RIKEN Center for Sustainable Resource Science, Yokohama, Japan
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Komaba, Meguro-ku, Tokyo, Japan
| | | | - Keita Fukuda
- Department of Biology, Tokyo Gakugei University, Koganei-shi, Tokyo, Japan
| | - Shizuka Gunji
- Department of Biology, Tokyo Gakugei University, Koganei-shi, Tokyo, Japan
| | - Mariko Asaoka
- Department of Biology, Tokyo Gakugei University, Koganei-shi, Tokyo, Japan
- Laboratoire de Reproduction et Développement des Plantes, Université de Lyon, UCB Lyon 1, ENS de Lyon, INRA, CNRS, Lyon, France
| | | | - Mitsunori Seo
- RIKEN Center for Sustainable Resource Science, Yokohama, Japan
| | - Hirokazu Tsukaya
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Ali Ferjani
- Department of Biology, Tokyo Gakugei University, Koganei-shi, Tokyo, Japan
| |
Collapse
|
10
|
Metabolic Control of Gametophore Shoot Formation through Arginine in the Moss Physcomitrium patens. Cell Rep 2021; 32:108127. [PMID: 32905770 DOI: 10.1016/j.celrep.2020.108127] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 07/20/2020] [Accepted: 08/18/2020] [Indexed: 12/13/2022] Open
Abstract
Shoot formation is accompanied by active cell proliferation and expansion, requiring that metabolic state adapts to developmental control. Despite the importance of such metabolic reprogramming, it remains unclear how development and metabolism are integrated. Here, we show that disruption of ANGUSTIFOLIA3 orthologs (PpAN3s) compromises gametophore shoot formation in the moss Physcomitrium patens due to defective cell proliferation and expansion. Trans-omics analysis reveals that the downstream activity of PpAN3 is linked to arginine metabolism. Elevating arginine level by chemical treatment leads to stunted gametophores and causes Ppan3 mutant-like transcriptional changes in the wild-type plant. Furthermore, ectopic expression of AtAN3 from Arabidopsis thaliana ameliorates the defective arginine metabolism and promotes gametophore formation in Ppan3 mutants. Together, these findings indicate that arginine metabolism is a key pathway associated with gametophore formation and provide evolutionary insights into the establishment of the shoot system in land plants through the integration of developmental and metabolic processes.
Collapse
|
11
|
Pyrophosphate as an alternative energy currency in plants. Biochem J 2021; 478:1515-1524. [PMID: 33881486 DOI: 10.1042/bcj20200940] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 03/20/2021] [Accepted: 03/23/2021] [Indexed: 02/07/2023]
Abstract
In the conditions of [Mg2+] elevation that occur, in particular, under low oxygen stress and are the consequence of the decrease in [ATP] and increase in [ADP] and [AMP], pyrophosphate (PPi) can function as an alternative energy currency in plant cells. In addition to its production by various metabolic pathways, PPi can be synthesized in the combined reactions of pyruvate, phosphate dikinase (PPDK) and pyruvate kinase (PK) by so-called PK/PPDK substrate cycle, and in the reverse reaction of membrane-bound H+-pyrophosphatase, which uses the energy of electrochemical gradients generated on tonoplast and plasma membrane. The PPi can then be consumed in its active forms of MgPPi and Mg2PPi by PPi-utilizing enzymes, which require an elevated [Mg2+]. This ensures a continuous operation of glycolysis in the conditions of suppressed ATP synthesis, keeping metabolism energy efficient and less dependent on ATP.
Collapse
|
12
|
Kleczkowski LA, Igamberdiev AU. Magnesium Signaling in Plants. Int J Mol Sci 2021; 22:1159. [PMID: 33503839 PMCID: PMC7865908 DOI: 10.3390/ijms22031159] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2020] [Revised: 01/16/2021] [Accepted: 01/19/2021] [Indexed: 01/02/2023] Open
Abstract
Free magnesium (Mg2+) is a signal of the adenylate (ATP+ADP+AMP) status in the cells. It results from the equilibrium of adenylate kinase (AK), which uses Mg-chelated and Mg-free adenylates as substrates in both directions of its reaction. The AK-mediated primary control of intracellular [Mg2+] is finely interwoven with the operation of membrane-bound adenylate- and Mg2+-translocators, which in a given compartment control the supply of free adenylates and Mg2+ for the AK-mediated equilibration. As a result, [Mg2+] itself varies both between and within the compartments, depending on their energetic status and environmental clues. Other key nucleotide-utilizing/producing enzymes (e.g., nucleoside diphosphate kinase) may also be involved in fine-tuning of the intracellular [Mg2+]. Changes in [Mg2+] regulate activities of myriads of Mg-utilizing/requiring enzymes, affecting metabolism under both normal and stress conditions, and impacting photosynthetic performance, respiration, phloem loading and other processes. In compartments controlled by AK equilibrium (cytosol, chloroplasts, mitochondria, nucleus), the intracellular [Mg2+] can be calculated from total adenylate contents, based on the dependence of the apparent equilibrium constant of AK on [Mg2+]. Magnesium signaling, reflecting cellular adenylate status, is likely widespread in all eukaryotic and prokaryotic organisms, due simply to the omnipresent nature of AK and to its involvement in adenylate equilibration.
Collapse
Affiliation(s)
- Leszek A. Kleczkowski
- Department of Plant Physiology, Umeå Plant Science Centre, University of Umeå, 901 87 Umeå, Sweden
| | - Abir U. Igamberdiev
- Department of Biology, Memorial University of Newfoundland, St. John’s, NL A1B3X9, Canada;
| |
Collapse
|
13
|
Lee SK, Jeon JS. Review: Crucial role of inorganic pyrophosphate in integrating carbon metabolism from sucrose breakdown to starch synthesis in rice endosperm. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2020; 298:110572. [PMID: 32771173 DOI: 10.1016/j.plantsci.2020.110572] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Revised: 05/28/2020] [Accepted: 06/19/2020] [Indexed: 06/11/2023]
Abstract
The endosperm is a primary constituent of mature seeds in rice as well as in other cereal crops, serving as the major storage reserve of starch. Observations indicate that the central part of the endosperm is subject to hypoxic conditions, which require a switch of energy metabolism owing to limited mitochondrial respiration. Uniquely, this endosperm generates a large source of inorganic pyrophosphate (PPi) as a byproduct of the reaction of ADP glucose pyrophosphorylase in the cytosol. Recent results derived from examination of the mutants of cereal crops, especially rice, for PPi-utilizing enzymes clearly suggest an important role of PPi as an alternative energy currency for integrating carbon metabolism from sucrose breakdown to starch synthesis in the endosperm. Thus, the present review provides an outline of the interlaced PPi-dependent metabolic pathways, which are critical for starch synthesis in the endosperm in terms of energy metabolism, along with its application to enhance yield potential.
Collapse
Affiliation(s)
- Sang-Kyu Lee
- Graduate School of Biotechnology and Crop Biotech Institute, Kyung Hee University, Yongin 17104, South Korea
| | - Jong-Seong Jeon
- Graduate School of Biotechnology and Crop Biotech Institute, Kyung Hee University, Yongin 17104, South Korea.
| |
Collapse
|
14
|
Pérez-Castiñeira JR, Serrano A. The H +-Translocating Inorganic Pyrophosphatase From Arabidopsis thaliana Is More Sensitive to Sodium Than Its Na +-Translocating Counterpart From Methanosarcina mazei. FRONTIERS IN PLANT SCIENCE 2020; 11:1240. [PMID: 32903538 PMCID: PMC7438732 DOI: 10.3389/fpls.2020.01240] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Accepted: 07/28/2020] [Indexed: 06/11/2023]
Abstract
Overexpression of membrane-bound K+-dependent H+-translocating inorganic pyrophosphatases (H+-PPases) from higher plants has been widely used to alleviate the sensitivity toward NaCl in these organisms, a strategy that had been previously tested in Saccharomyces cerevisiae. On the other hand, H+-PPases have been reported to functionally complement the yeast cytosolic soluble pyrophosphatase (IPP1). Here, the efficiency of the K+-dependent Na+-PPase from the archaeon Methanosarcina mazei (MVP) to functionally complement IPP1 has been compared to that of its H+-pumping counterpart from Arabidopsis thaliana (AVP1). Both membrane-bound integral PPases (mPPases) supported yeast growth equally well under normal conditions, however, cells expressing MVP grew significantly better than those expressing AVP1 under salt stress. The subcellular distribution of the heterologously-expressed mPPases was crucial in order to observe the phenotypes associated with the complementation. In vitro studies showed that the PPase activity of MVP was less sensitive to Na+ than that of AVP1. Consistently, when yeast cells expressing MVP were grown in the presence of NaCl only a marginal increase in their internal PPi levels was observed with respect to control cells. By contrast, yeast cells that expressed AVP1 had significantly higher levels of this metabolite under the same conditions. The H+-pumping activity of AVP1 was also markedly inhibited by Na+. Our results suggest that mPPases primarily act by hydrolysing the PPi generated in the cytosol when expressed in yeast, and that AVP1 is more susceptible to Na+ inhibition than MVP both in vivo and in vitro. Based on this experimental evidence, we propose Na+-PPases as biotechnological tools to generate salt-tolerant plants.
Collapse
Affiliation(s)
| | - Aurelio Serrano
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla-CSIC, Sevilla, Spain
| |
Collapse
|
15
|
Biochemical characterization of phosphoenolpyruvate carboxykinases from Arabidopsis thaliana. Biochem J 2020; 476:2939-2952. [PMID: 31548269 DOI: 10.1042/bcj20190523] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 09/19/2019] [Accepted: 09/23/2019] [Indexed: 01/01/2023]
Abstract
ATP-dependent phosphoenolpyruvate carboxykinases (PEPCKs, EC 4.1.1.49) from C4 and CAM plants have been widely studied due to their crucial role in photosynthetic CO2 fixation. However, our knowledge on the structural, kinetic and regulatory properties of the enzymes from C3 species is still limited. In this work, we report the recombinant production and biochemical characterization of two PEPCKs identified in Arabidopsis thaliana: AthPEPCK1 and AthPEPCK2. We found that both enzymes exhibited high affinity for oxaloacetate and ATP, reinforcing their role as decarboxylases. We employed a high-throughput screening for putative allosteric regulators using differential scanning fluorometry and confirmed their effect on enzyme activity by performing enzyme kinetics. AthPEPCK1 and AthPEPCK2 are allosterically modulated by key intermediates of plant metabolism, namely succinate, fumarate, citrate and α-ketoglutarate. Interestingly, malate activated and glucose 6-phosphate inhibited AthPEPCK1 but had no effect on AthPEPCK2. Overall, our results demonstrate that the enzymes involved in the critical metabolic node constituted by phosphoenolpyruvate are targets of fine allosteric regulation.
Collapse
|
16
|
Fujikura U, Ezaki K, Horiguchi G, Seo M, Kanno Y, Kamiya Y, Lenhard M, Tsukaya H. Suppression of class I compensated cell enlargement by xs2 mutation is mediated by salicylic acid signaling. PLoS Genet 2020; 16:e1008873. [PMID: 32584819 PMCID: PMC7343186 DOI: 10.1371/journal.pgen.1008873] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 07/08/2020] [Accepted: 05/20/2020] [Indexed: 11/18/2022] Open
Abstract
The regulation of leaf size has been studied for decades. Enhancement of post-mitotic cell expansion triggered by impaired cell proliferation in Arabidopsis is an important process for leaf size regulation, and is known as compensation. This suggests a key interaction between cell proliferation and cell expansion during leaf development. Several studies have highlighted the impact of this integration mechanism on leaf size determination; however, the molecular basis of compensation remains largely unknown. Previously, we identified extra-small sisters (xs) mutants which can suppress compensated cell enlargement (CCE) via a specific defect in cell expansion within the compensation-exhibiting mutant, angustifolia3 (an3). Here we revealed that one of the xs mutants, namely xs2, can suppress CCE not only in an3 but also in other compensation-exhibiting mutants erecta (er) and fugu2. Molecular cloning of XS2 identified a deleterious mutation in CATION CALCIUM EXCHANGER 4 (CCX4). Phytohormone measurement and expression analysis revealed that xs2 shows hyper activation of the salicylic acid (SA) response pathway, where activation of SA response can suppress CCE in compensation mutants. All together, these results highlight the regulatory connection which coordinates compensation and SA response. Leaves are determinate organ and size of leaves are determined by intrinsic and extrinsic cues. Cell proliferation and post-mitotic cell expansion should be coordinated during leaf morphogenesis to develop appropriate size depending on its developmental programs. Recent studies highlighted the existence of integrated mechanism which coordinates cell proliferation and cell expansion during leaf development. Compensation, which is enhanced post-mitotic cell expansion accompanied by a significant decrease in cell number during leaf organogenesis, is one of the clues for such coordination. However, the molecular mechanisms linking cell proliferation and cell expansion are still poorly understood. Previously, we reported extra-small sisters 2 (xs2) mutation caused specific defect in cell expansion and it suppressed increased post-mitotic cell enlargement in angustifolia3 (an3) mutant, which exhibits typical compensation. Here we identify the affected gene of xs2 mutant encodes a member of cation calcium exchanger which is believed to be involved in cation homeostasis within cells. Loss of function of this protein causes hyper accumulation of salicylic acid (SA) and increased expression of pathogen related genes. Physiological and genetic studies revealed activated SA signal transduction reduced cell size. It suppressed post-mitotic cell expansion in several compensation mutants not only an3 but partially suppressed in another type of compensation mutant which increases size of mitotic cells. This finding suggests post-mitotic cell expansion pathway is regulated in common by SA-dependent signaling and by compensation signaling during leaf development.
Collapse
Affiliation(s)
- Ushio Fujikura
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Japan
- * E-mail:
| | - Kazune Ezaki
- Graduate School of Science, The University of Tokyo, Japan
| | - Gorou Horiguchi
- Department of Life Science, College of Science, Rikkyo University, Japan
| | - Mitsunori Seo
- RIKEN Center for Sustainable Resource Science, Japan
| | - Yuri Kanno
- RIKEN Center for Sustainable Resource Science, Japan
| | - Yuji Kamiya
- RIKEN Center for Sustainable Resource Science, Japan
| | - Michael Lenhard
- Institut für Biochemie und Biologie, Universität Potsdam, Potsdam-Golm, Germany
| | - Hirokazu Tsukaya
- Graduate School of Science, The University of Tokyo, Japan
- Okazaki Institute for Integrative Bioscience, Japan
| |
Collapse
|
17
|
Gunji S, Oda Y, Takigawa-Imamura H, Tsukaya H, Ferjani A. Excess Pyrophosphate Restrains Pavement Cell Morphogenesis and Alters Organ Flatness in Arabidopsis thaliana. FRONTIERS IN PLANT SCIENCE 2020; 11:31. [PMID: 32153602 PMCID: PMC7047283 DOI: 10.3389/fpls.2020.00031] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 01/13/2020] [Indexed: 05/31/2023]
Abstract
In Arabidopsis thaliana, the vacuolar proton-pumping pyrophosphatase (H+-PPase) is highly expressed in young tissues, which consume large amounts of energy in the form of nucleoside triphosphates and produce pyrophosphate (PPi) as a byproduct. We reported that excess PPi in the H+-PPase loss-of-function fugu5 mutant severely compromised gluconeogenesis from seed storage lipids, arrested cell division in cotyledonary palisade tissue, and triggered compensated cell enlargement; this phenotype was recovered upon sucrose supply. Thus, we provided evidence that the hydrolysis of inhibitory PPi, rather than vacuolar acidification, is the major contribution of H+-PPase during seedling establishment. Here, examination of the epidermis revealed that fugu5 pavement cells exhibited defective puzzle-cell formation. Importantly, removal of PPi from fugu5 background by the yeast cytosolic PPase IPP1, in fugu5-1 AVP1pro::IPP1 transgenic lines, restored the phenotypic aberrations of fugu5 pavement cells. Surprisingly, pavement cells in mutants with defects in gluconeogenesis (pck1-2) or the glyoxylate cycle (icl-2; mls-2) showed no phenotypic alteration, indicating that reduced sucrose production from seed storage lipids is not the cause of fugu5 epidermal phenotype. fugu5 had oblong cotyledons similar to those of angustifolia-1 (an-1), whose leaf pavement cells display an abnormal arrangement of cortical microtubules (MTs). To gain insight into the genetic interaction between ANGUSTIFOLIA and H+-PPase in pavement cell differentiation, an-1 fugu5-1 was analyzed. Surprisingly, epidermis developmental defects were synergistically enhanced in the double mutant. In fact, an-1 fugu5-1 pavement cells showed a striking three-dimensional growth phenotype on both abaxial and adaxial sides of cotyledons, which was recovered by hydrolysis of PPi in an-1 fugu5-1 AVP1pro::IPP1. Live imaging revealed that cortical MTs exhibited a reduced velocity, were slightly fragmented and sparse in the above lines compared to the WT. Consistently, addition of PPi in vitro led to a dose-dependent delay of tubulin polymerization, thus supporting a link between PPi and MT dynamics. Moreover, mathematical simulation of three-dimensional growth based on cotyledon proximo-distal and medio-lateral phenotypic quantification implicated restricted cotyledon expansion along the medio-lateral axis in the crinkled surface of an-1 fugu5-1. Together, our data suggest that PPi homeostasis is a prerequisite for proper pavement cell morphogenesis, epidermal growth and development, and organ flattening.
Collapse
Affiliation(s)
- Shizuka Gunji
- United Graduate School of Education, Tokyo Gakugei University, Tokyo, Japan
| | - Yoshihisa Oda
- Department of Gene Function and Phenomics, National Institute of Genetics, Mishima, Japan
- Department of Genetics, The Graduate University for Advanced Studies, SOKENDAI, Mishima, Japan
| | - Hisako Takigawa-Imamura
- Department of Anatomy and Cell Biology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Hirokazu Tsukaya
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Ali Ferjani
- United Graduate School of Education, Tokyo Gakugei University, Tokyo, Japan
- Department of Biology, Tokyo Gakugei University, Tokyo, Japan
| |
Collapse
|
18
|
Asaoka M, Inoue SI, Gunji S, Kinoshita T, Maeshima M, Tsukaya H, Ferjani A. Excess Pyrophosphate within Guard Cells Delays Stomatal Closure. PLANT & CELL PHYSIOLOGY 2019; 60:875-887. [PMID: 30649470 DOI: 10.1093/pcp/pcz002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Accepted: 12/28/2018] [Indexed: 05/08/2023]
Abstract
A variety of cellular metabolic reactions generate inorganic pyrophosphate (PPi) as an ATP hydrolysis byproduct. The vacuolar H+-translocating pyrophosphatase (H+-PPase) loss-of-function fugu5 mutant is susceptible to drought and displays pleotropic postgerminative growth defects due to excess PPi. It was recently reported that stomatal closure after abscisic acid (ABA) treatment is delayed in vhp1-1, a fugu5 allele. In contrast, we found that specific removal of PPi rescued all of the above fugu5 developmental and growth defects. Hence, we speculated that excess PPi itself, rather than vacuolar acidification, might delay stomatal closure. To test this hypothesis, we constructed transgenic plants expressing the yeast IPP1 gene (encoding a cytosolic pyrophosphatase) driven by a guard cell-specific promoter (pGC1::IPP1) in the fugu5 background. Our measurements confirmed stomatal closure defects in fugu5, further supporting a role for H+-PPase in stomatal functioning. Importantly, while pGC1::IPP1 transgenics morphologically mimicked fugu5, stomatal closure was restored in response to ABA and darkness. Quantification of water loss revealed that fugu5 stomata were almost completely insensitive to ABA. In addition, growth of pGC1::IPP1 plants was promoted compared to fugu5 throughout their life; however, it did not reach the wild type level. fugu5 also displayed an increased stomatal index, in violation of the one-cell-spacing rule, and phenotypes recovered upon removal of PPi by pAVP1::IPP1 (FUGU5, VHP1 and AVP1 are the same gene encoding H+-PPase), but not in the pGC1::IPP1 line. Taken together, these results clearly support our hypothesis that dysfunction in stomata is triggered by excess PPi within guard cells, probably via perturbed guard cell metabolism.
Collapse
Affiliation(s)
- Mariko Asaoka
- Department of Biology, Tokyo Gakugei University, Koganei-shi, Tokyo, Japan
| | - Shin-Ichiro Inoue
- Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, Japan
| | - Shizuka Gunji
- United Graduated School of Education, Tokyo Gakugei University, Tokyo, Japan
| | - Toshinori Kinoshita
- Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, Japan
- Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Nagoya, Japan
| | - Masayoshi Maeshima
- Laboratory of Cell Dynamics, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
| | - Hirokazu Tsukaya
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
- Exploratory Research Center on Life and Living Systems (ExCELLS), Okazaki, Aichi, Japan
| | - Ali Ferjani
- Department of Biology, Tokyo Gakugei University, Koganei-shi, Tokyo, Japan
- United Graduated School of Education, Tokyo Gakugei University, Tokyo, Japan
| |
Collapse
|
19
|
Patir-Nebioglu MG, Andrés Z, Krebs M, Fink F, Drzewicka K, Stankovic-Valentin N, Segami S, Schuck S, Büttner M, Hell R, Maeshima M, Melchior F, Schumacher K. Pyrophosphate modulates plant stress responses via SUMOylation. eLife 2019; 8:44213. [PMID: 30785397 PMCID: PMC6382351 DOI: 10.7554/elife.44213] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Accepted: 02/05/2019] [Indexed: 01/11/2023] Open
Abstract
Pyrophosphate (PPi), a byproduct of macromolecule biosynthesis is maintained at low levels by soluble inorganic pyrophosphatases (sPPase) found in all eukaryotes. In plants, H+-pumping pyrophosphatases (H+-PPase) convert the substantial energy present in PPi into an electrochemical gradient. We show here, that both cold- and heat stress sensitivity of fugu5 mutants lacking the major H+-PPase isoform AVP1 is correlated with reduced SUMOylation. In addition, we show that increased PPi concentrations interfere with SUMOylation in yeast and we provide evidence that SUMO activating E1-enzymes are inhibited by micromolar concentrations of PPi in a non-competitive manner. Taken together, our results do not only provide a mechanistic explanation for the beneficial effects of AVP1 overexpression in plants but they also highlight PPi as an important integrator of metabolism and stress tolerance.
Collapse
Affiliation(s)
- M Görkem Patir-Nebioglu
- Department Cell Biology, Centre for Organismal Studies (COS), Heidelberg University, Heidelberg, Germany
| | - Zaida Andrés
- Department Cell Biology, Centre for Organismal Studies (COS), Heidelberg University, Heidelberg, Germany
| | - Melanie Krebs
- Department Cell Biology, Centre for Organismal Studies (COS), Heidelberg University, Heidelberg, Germany
| | - Fabian Fink
- Department Cell Biology, Centre for Organismal Studies (COS), Heidelberg University, Heidelberg, Germany
| | - Katarzyna Drzewicka
- Center for Molecular Biology of Heidelberg University (ZMBH) and DKFZ - ZMBH Alliance, Heidelberg, Germany
| | - Nicolas Stankovic-Valentin
- Center for Molecular Biology of Heidelberg University (ZMBH) and DKFZ - ZMBH Alliance, Heidelberg, Germany
| | - Shoji Segami
- Laboratory of Cell Dynamics, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
| | - Sebastian Schuck
- Center for Molecular Biology of Heidelberg University (ZMBH) and DKFZ - ZMBH Alliance, Heidelberg, Germany
| | - Michael Büttner
- Metabolomics Core Technology Platform, Centre for Organismal Studies (COS), Heidelberg University, Heidelberg, Germany
| | - Rüdiger Hell
- Metabolomics Core Technology Platform, Centre for Organismal Studies (COS), Heidelberg University, Heidelberg, Germany
| | - Masayoshi Maeshima
- Laboratory of Cell Dynamics, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
| | - Frauke Melchior
- Center for Molecular Biology of Heidelberg University (ZMBH) and DKFZ - ZMBH Alliance, Heidelberg, Germany
| | - Karin Schumacher
- Department Cell Biology, Centre for Organismal Studies (COS), Heidelberg University, Heidelberg, Germany
| |
Collapse
|
20
|
Vacuolar Proton Pyrophosphatase Is Required for High Magnesium Tolerance in Arabidopsis. Int J Mol Sci 2018; 19:ijms19113617. [PMID: 30453498 PMCID: PMC6274811 DOI: 10.3390/ijms19113617] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Revised: 11/11/2018] [Accepted: 11/11/2018] [Indexed: 11/17/2022] Open
Abstract
Magnesium (Mg2+) is an essential nutrient in all organisms. However, high levels of Mg2+ in the environment are toxic to plants. In this study, we identified the vacuolar-type H⁺-pyrophosphatase, AVP1, as a critical enzyme for optimal plant growth under high-Mg conditions. The Arabidopsis avp1 mutants displayed severe growth retardation, as compared to the wild-type plants upon excessive Mg2+. Unexpectedly, the avp1 mutant plants retained similar Mg content to wild-type plants under either normal or high Mg conditions, suggesting that AVP1 may not directly contribute to Mg2+ homeostasis in plant cells. Further analyses confirmed that the avp1 mutant plants contained a higher pyrophosphate (PPi) content than wild type, coupled with impaired vacuolar H⁺-pyrophosphatase activity. Interestingly, expression of the Saccharomyces cerevisiae cytosolic inorganic pyrophosphatase1 gene IPP1, which facilitates PPi hydrolysis but not proton translocation into vacuole, rescued the growth defects of avp1 mutants under high-Mg conditions. These results provide evidence that high-Mg sensitivity in avp1 mutants possibly resulted from elevated level of cytosolic PPi. Moreover, genetic analysis indicated that mutation of AVP1 was additive to the defects in mgt6 and cbl2 cbl3 mutants that are previously known to be impaired in Mg2+ homeostasis. Taken together, our results suggest AVP1 is required for cellular PPi homeostasis that in turn contributes to high-Mg tolerance in plant cells.
Collapse
|