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Williamson G, Harris T, Bizior A, Hoskisson PA, Pritchard L, Javelle A. Biological ammonium transporters: evolution and diversification. FEBS J 2024. [PMID: 38265636 DOI: 10.1111/febs.17059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 12/14/2023] [Accepted: 01/09/2024] [Indexed: 01/25/2024]
Abstract
Although ammonium is the preferred nitrogen source for microbes and plants, in animal cells it is a toxic product of nitrogen metabolism that needs to be excreted. Thus, ammonium movement across biological membranes, whether for uptake or excretion, is a fundamental and ubiquitous biological process catalysed by the superfamily of the Amt/Mep/Rh transporters. A remarkable feature of the Amt/Mep/Rh family is that they are ubiquitous and, despite sharing low amino acid sequence identity, are highly structurally conserved. Despite sharing a common structure, these proteins have become involved in a diverse range of physiological process spanning all domains of life, with reports describing their involvement in diverse biological processes being published regularly. In this context, we exhaustively present their range of biological roles across the domains of life and after explore current hypotheses concerning their evolution to help to understand how and why the conserved structure fulfils diverse physiological functions.
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Affiliation(s)
- Gordon Williamson
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, UK
| | - Thomas Harris
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, UK
| | - Adriana Bizior
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, UK
| | - Paul Alan Hoskisson
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, UK
| | - Leighton Pritchard
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, UK
| | - Arnaud Javelle
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, UK
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2
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Jain D, Schmidt W. Protein Phosphorylation Orchestrates Acclimations of Arabidopsis Plants to Environmental pH. Mol Cell Proteomics 2024; 23:100685. [PMID: 38000714 PMCID: PMC10837763 DOI: 10.1016/j.mcpro.2023.100685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2023] [Revised: 10/18/2023] [Accepted: 11/16/2023] [Indexed: 11/26/2023] Open
Abstract
Environment pH (pHe) is a key parameter dictating a surfeit of conditions critical to plant survival and fitness. To elucidate the mechanisms that recalibrate cytoplasmic and apoplastic pH homeostasis, we conducted a comprehensive proteomic/phosphoproteomic inventory of plants subjected to transient exposure to acidic or alkaline pH, an approach that covered the majority of protein-coding genes of the reference plant Arabidopsis thaliana. Our survey revealed a large set-of so far undocumented pHe-dependent phospho-sites, indicative of extensive post-translational regulation of proteins involved in the acclimation to pHe. Changes in pHe altered both electrogenic H+ pumping via P-type ATPases and H+/anion co-transport processes, putatively leading to altered net trans-plasma membrane translocation of H+ ions. In pH 7.5 plants, the transport (but not the assimilation) of nitrogen via NRT2-type nitrate and AMT1-type ammonium transporters was induced, conceivably to increase the cytosolic H+ concentration. Exposure to both acidic and alkaline pH resulted in a marked repression of primary root elongation. No such cessation was observed in nrt2.1 mutants. Alkaline pH decreased the number of root hairs in the wild type but not in nrt2.1 plants, supporting a role of NRT2.1 in developmental signaling. Sequestration of iron into the vacuole via alterations in protein abundance of the vacuolar iron transporter VTL5 was inversely regulated in response to high and low pHe, presumptively in anticipation of associated changes in iron availability. A pH-dependent phospho-switch was also observed for the ABC transporter PDR7, suggesting changes in activity and, possibly, substrate specificity. Unexpectedly, the effect of pHe was not restricted to roots and provoked pronounced changes in the shoot proteome. In both roots and shoots, the plant-specific TPLATE complex components AtEH1 and AtEH2-essential for clathrin-mediated endocytosis-were differentially phosphorylated at multiple sites in response to pHe, indicating that the endocytic cargo protein trafficking is orchestrated by pHe.
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Affiliation(s)
- Dharmesh Jain
- Molecular and Biological Agricultural Sciences Program, Taiwan International Graduate Program, Academia Sinica and National Chung-Hsing University, Taipei, Taiwan; Graduate Institute of Biotechnology, National Chung-Hsing University, Taichung, Taiwan; Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
| | - Wolfgang Schmidt
- Molecular and Biological Agricultural Sciences Program, Taiwan International Graduate Program, Academia Sinica and National Chung-Hsing University, Taipei, Taiwan; Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan; Biotechnology Center, National Chung-Hsing University, Taichun, Taiwan; Genome and Systems Biology Degree Program, College of Life Science, National Taiwan University, Taipei, Taiwan.
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3
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Jung EH, Nguyen J, Nelson C, Brauner CJ, Wood CM. Ammonia transport is independent of PNH 3 gradients across the gastrointestinal epithelia of the rainbow trout: A role for the stomach. JOURNAL OF EXPERIMENTAL ZOOLOGY. PART A, ECOLOGICAL AND INTEGRATIVE PHYSIOLOGY 2023; 339:180-192. [PMID: 36369634 DOI: 10.1002/jez.2670] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 10/01/2022] [Accepted: 10/05/2022] [Indexed: 11/13/2022]
Abstract
Although the gastrointestinal tract (GIT) is an important site for nitrogen metabolism in teleosts, the mechanisms of ammonia absorption and transport remain to be elucidated. Both protein catabolism in the lumen and the metabolism of the GIT tissues produce ammonia which, in part, enters the portal blood through the anterior region of the GIT. The present study examined the possible roles of different GIT sections of rainbow trout (Oncorhynchus mykiss) in transporting ammonia in its unionized gas form-NH3 -by changing the PNH3 gradient across GIT epithelia using in vitro gut sac preparations. We also surveyed messenger RNA expression patterns of three of the identified Rh proteins (Rhbg, Rhcg1, and Rhcg2) as potential NH3 transporters and NKCC as a potential ammonium ion (NH4 + ) transporter along the GIT of rainbow trout. We found that ammonia absorption is not dependent on the PNH3 gradient despite expression of Rhbg and Rhcg2 in the intestinal tissues, and Rhcg2 in the stomach. We detected no expression of Rhbg in the stomach and no expression of Rhcg1 in any GIT tissues. There was also a lack of correlation between ammonia transport and [NH4 + ] gradient despite NKCC expression in all GIT tissues. Regardless of PNH3 gradients, the stomach showed the greatest absorption and net tissue consumption of ammonia. Overall, our findings suggest nitrogen metabolism zonation of GIT, with stomach serving as an important site for the absorption, handling and transport of ammonia that is independent of the PNH3 gradient.
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Affiliation(s)
- Ellen H Jung
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Jessica Nguyen
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Charlotte Nelson
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Colin J Brauner
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Chris M Wood
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
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Densi A, Iyer RS, Bhat PJ. Synonymous and Nonsynonymous Substitutions in Dictyostelium discoideum Ammonium Transporter amtA Are Necessary for Functional Complementation in Saccharomyces cerevisiae. Microbiol Spectr 2023; 11:e0384722. [PMID: 36840598 PMCID: PMC10100761 DOI: 10.1128/spectrum.03847-22] [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: 09/21/2022] [Accepted: 01/24/2023] [Indexed: 02/24/2023] Open
Abstract
Ammonium transporters are present in all three domains of life. They have undergone extensive horizontal gene transfer (HGT), gene duplication, and functional diversification and therefore offer an excellent paradigm to study protein evolution. We attempted to complement a mep1Δmep2Δmep3Δ strain of Saccharomyces cerevisiae (triple-deletion strain), which otherwise cannot grow on ammonium as a sole nitrogen source at concentrations of <3 mM, with amtA of Dictyostelium discoideum, an orthologue of S. cerevisiae MEP2. We observed that amtA did not complement the triple-deletion strain of S. cerevisiae for growth on low-ammonium medium. We isolated two mutant derivatives of amtA (amtA M1 and amtA M2) from a PCR-generated mutant plasmid library that complemented the triple-deletion strain of S. cerevisiae. amtA M1 bears three nonsynonymous and two synonymous substitutions, which are necessary for its functionality. amtA M2 bears two nonsynonymous substitutions and one synonymous substitution, all of which are necessary for functionality. Interestingly, AmtA M1 transports ammonium but does not confer methylamine toxicity, while AmtA M2 transports ammonium and confers methylamine toxicity, demonstrating functional diversification. Preliminary biochemical analyses indicated that the mutants differ in their conformations as well as their mechanisms of ammonium transport. These intriguing results clearly point out that protein evolution cannot be fathomed by studying nonsynonymous and synonymous substitutions in isolation. The above-described observations have significant implications for various facets of biological processes and are discussed in detail. IMPORTANCE Functional diversification following gene duplication is one of the major driving forces of protein evolution. While the role of nonsynonymous substitutions in the functional diversification of proteins is well recognized, knowledge of the role of synonymous substitutions in protein evolution is in its infancy. Using functional complementation, we isolated two functional alleles of the D. discoideum ammonium transporter gene (amtA), which otherwise does not function in S. cerevisiae as an ammonium transporters. One of them is an ammonium transporter, while the other is an ammonium transporter that also confers methylammonium (ammonium analogue) toxicity, suggesting functional diversification. Surprisingly, both alleles require a combination of synonymous and nonsynonymous substitutions for their functionality. These results bring out a hitherto-unknown pathway of protein evolution and pave the way for not only understanding protein evolution but also interpreting single nucleotide polymorphisms (SNPs).
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Affiliation(s)
- Asha Densi
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, India
| | - Revathi S. Iyer
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, India
| | - Paike Jayadeva Bhat
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, India
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Latorre Estivalis JM, Traverso L, Pontes G, Lorenzo MG. The antennal transcriptome of Triatoma infestans reveals substantial expression changes triggered by a blood meal. BMC Genomics 2022; 23:861. [PMID: 36585617 PMCID: PMC9801554 DOI: 10.1186/s12864-022-09059-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Accepted: 11/30/2022] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND Triatoma infestans is the main vector of Chagas disease in the Americas, currently transmitting it in Argentina, Paraguay, and Bolivia. Many T. infestans populations present insecticide resistance, reducing the efficiency of control campaigns. Alternative vector control methods are needed, and molecular targets mediating fundamental physiological processes can be a promising option to manipulate kissing bug behavior. Therefore, it is necessary to characterize the main sensory targets, as well as to determine whether they are modulated by physiological factors. In order to identify gene candidates potentially mediating host cue detection, the antennal transcripts of T. infestans fifth instar larvae were sequenced and assembled. Besides, we evaluated whether a blood meal had an effect on transcriptional profiles, as responsiveness to host-emitted sensory cues depends on bug starvation. RESULTS The sensory-related gene families of T. infestans were annotated (127 odorant receptors, 38 ionotropic receptors, 11 gustatory receptors, 41 odorant binding proteins, and 25 chemosensory proteins, among others) and compared to those of several other hemipterans, including four triatomine species. Several triatomine-specific lineages representing sensory adaptations developed through the evolution of these blood-feeding heteropterans were identified. As well, we report here various conserved sensory gene orthogroups shared by heteropterans. The absence of the thermosensor pyrexia, of pickpocket receptor subfamilies IV and VII, together with clearly expanded takeout repertoires, are revealed features of the molecular bases of heteropteran antennal physiology. Finally, out of 2,122 genes whose antennal expression was significantly altered by the ingestion of a blood meal, a set of 41 T. infestans sensory-related genes (9 up-regulated; 32 down-regulated) was detected. CONCLUSIONS We propose that the set of genes presenting nutritionally-triggered modulation on their expression represent candidates to mediate triatomine host-seeking behavior. Besides, the triatomine-specific gene lineages found represent molecular adaptations to their risky natural history that involves stealing blood from an enormously diverse set of vertebrates. Heteropteran gene orthogroups identified may represent unknown features of the sensory specificities of this largest group of hemipteroids. Our work is the first molecular characterization of the peripheral modulation of sensory processes in a non-dipteran vector of human disease.
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Affiliation(s)
- Jose Manuel Latorre Estivalis
- grid.7345.50000 0001 0056 1981Laboratorio de Insectos Sociales, Instituto de Fisiología, Biología Molecular y Neurociencias, Universidad de Buenos Aires - CONICET, Ciudad Autónoma de Buenos Aires, Argentina
| | - Lucila Traverso
- grid.423606.50000 0001 1945 2152Laboratorio de Neurobiología de Insectos (LNI), Centro Regional de Estudios Genómicos, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, CENEXA, CONICET, La Plata, Buenos Aires, Argentina
| | - Gina Pontes
- grid.7345.50000 0001 0056 1981Laboratorio de Eco-Fisiología de Insectos del Instituto de Biodiversidad y Biología Experimental y Aplicada (IBBEA-UBA-CONICET), DBBE - Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Autónoma de Buenos Aires, Argentina
| | - Marcelo Gustavo Lorenzo
- grid.418068.30000 0001 0723 0931Vector Behaviour and Pathogen Interaction Group, Instituto René Rachou - FIOCRUZ-Minas, Belo Horizonte, Minas Gerais, Brazil
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Li J, Li W, Xu L, Wang M, Zhou W, Li S, Tan W, Wang Q, Xing W, Liu D. Acclimation of sugar beet in morphological, physiological and BvAMT1.2 expression under low and high nitrogen supply. PLoS One 2022; 17:e0278327. [PMID: 36445927 PMCID: PMC9707788 DOI: 10.1371/journal.pone.0278327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 11/15/2022] [Indexed: 12/03/2022] Open
Abstract
Understanding the response and tolerance mechanisms of nitrogen (N) stress is essential for the taproot plant of sugar beet. Hence, in this study, low (0.5 and 3 mmol/L; N0.5 and N3), moderate (5 mmol/L; N5; control) and high (10 and 12 mmol/L; N10 and N12) N were imposed to sugar beet to comparatively investigate the growth and physiological changes, and expression pattern of the gene involving ammonia transporting at different seedling stages. The results showed that, different from N5 which could induce maximum biomass of beet seedlings, low N was more likely to inhibit the growth of beet seedlings than high N treatments. Morphological differences and adverse factors increased significantly with extension of stress time, but sugar beet seedlings displayed a variety of physical responses to different N concentrations to adapt to N abnormal. At 14 d, the chlorophyll content, leaf and root surface area, total dry weight and nitrogen content of seedlings treated with N0.5 decreased 15.83%, 53.65%, 73.94%, 78.08% and 24.88% respectively, compared with N12; however, the root shoot ratio increased significantly as well as superoxide dismutase (SOD), peroxidase (POD), glutamine synthetase (GS) activity and malondialdehyde (MDA) and proline content, especially in root. The expression of BvAMT1.2 was also regulated in an N concentration-dependent manner, and was mainly involved in the tolerance of beet leaves to N stress, which significantly positively correlated to GS activity on the basis of its high affinity to N. It can be deduced that the stored nutrients under low N could only maintain relatively stable root growth, and faced difficulty in being transported to the shoots. Sugar beet was relatively resilient to N0.5 stress according to the mean affiliation function analysis. These results provide a theoretical basis for the extensive cultivation of sugar beet in N-stressed soil.
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Affiliation(s)
- Jiajia Li
- National Beet Medium-Term Gene Bank, Heilongjiang University, Harbin, P. R. China
- Key Laboratory of Sugar Beet Genetics and Breeding, Heilongjiang Province Common College/College of Advanced Agriculture and Ecological Environment, Heilongjiang University, Harbin, P. R. China
| | - Wangsheng Li
- National Beet Medium-Term Gene Bank, Heilongjiang University, Harbin, P. R. China
- Key Laboratory of Sugar Beet Genetics and Breeding, Heilongjiang Province Common College/College of Advanced Agriculture and Ecological Environment, Heilongjiang University, Harbin, P. R. China
| | - Lingqing Xu
- National Beet Medium-Term Gene Bank, Heilongjiang University, Harbin, P. R. China
- Key Laboratory of Sugar Beet Genetics and Breeding, Heilongjiang Province Common College/College of Advanced Agriculture and Ecological Environment, Heilongjiang University, Harbin, P. R. China
| | - Man Wang
- National Beet Medium-Term Gene Bank, Heilongjiang University, Harbin, P. R. China
- Key Laboratory of Sugar Beet Genetics and Breeding, Heilongjiang Province Common College/College of Advanced Agriculture and Ecological Environment, Heilongjiang University, Harbin, P. R. China
| | - Wanting Zhou
- National Beet Medium-Term Gene Bank, Heilongjiang University, Harbin, P. R. China
- Key Laboratory of Sugar Beet Genetics and Breeding, Heilongjiang Province Common College/College of Advanced Agriculture and Ecological Environment, Heilongjiang University, Harbin, P. R. China
| | - Siqi Li
- National Beet Medium-Term Gene Bank, Heilongjiang University, Harbin, P. R. China
- Key Laboratory of Sugar Beet Genetics and Breeding, Heilongjiang Province Common College/College of Advanced Agriculture and Ecological Environment, Heilongjiang University, Harbin, P. R. China
| | - Wenbo Tan
- National Beet Medium-Term Gene Bank, Heilongjiang University, Harbin, P. R. China
- Key Laboratory of Sugar Beet Genetics and Breeding, Heilongjiang Province Common College/College of Advanced Agriculture and Ecological Environment, Heilongjiang University, Harbin, P. R. China
| | - Qiuhong Wang
- Key Laboratory of Sugar Beet Genetics and Breeding, Heilongjiang Province Common College/College of Advanced Agriculture and Ecological Environment, Heilongjiang University, Harbin, P. R. China
| | - Wang Xing
- National Beet Medium-Term Gene Bank, Heilongjiang University, Harbin, P. R. China
- Key Laboratory of Sugar Beet Genetics and Breeding, Heilongjiang Province Common College/College of Advanced Agriculture and Ecological Environment, Heilongjiang University, Harbin, P. R. China
- * E-mail: (WX); (DL)
| | - Dali Liu
- National Beet Medium-Term Gene Bank, Heilongjiang University, Harbin, P. R. China
- Key Laboratory of Sugar Beet Genetics and Breeding, Heilongjiang Province Common College/College of Advanced Agriculture and Ecological Environment, Heilongjiang University, Harbin, P. R. China
- * E-mail: (WX); (DL)
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Duarte-Aké F, Márquez-López RE, Monroy-González Z, Borbolla-Pérez V, Loyola-Vargas VM. The source, level, and balance of nitrogen during the somatic embryogenesis process drive cellular differentiation. PLANTA 2022; 256:113. [PMID: 36367589 DOI: 10.1007/s00425-022-04009-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Accepted: 10/03/2022] [Indexed: 06/16/2023]
Abstract
Since the discovery of somatic embryogenesis (SE), it has been evident that nitrogen (N) metabolism is essential during morphogenesis and cell differentiation. Usually, N is supplied to cultures in vitro in three forms, ammonium (NH4+), nitrate (NO3-), and amino N from amino acids (AAs). Although most plants prefer NO3- to NH4+, NH4+ is the primary form route to be assimilated. The balance of NO3- and NH4+ determines if the morphological differentiation process will produce embryos. That the N reduction of NO3- is needed for both embryo initiation and maturation is well-established in several models, such as carrot, tobacco, and rose. It is clear that N is indispensable for SE, but the mechanism that triggers the signal for embryo formation remains unknown. Here, we discuss recent studies that suggest an optimal endogenous concentration of auxin and cytokinin is closely related to N supply to plant tissue. From a molecular and biochemical perspective, we explain N's role in embryo formation, hypothesizing possible mechanisms that allow cellular differentiation by changing the nitrogen source.
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Affiliation(s)
- Fátima Duarte-Aké
- Centro de Investigación Científica de Yucatán, Unidad de Bioquímica y Biología Molecular de Plantas, Mérida, Yucatán, Mexico
| | - Ruth E Márquez-López
- Instituto Politécnico Nacional, Centro Interdisciplinario de Investigación para el Desarrollo Integral Regional, Unidad Oaxaca, Santa Cruz Xoxocotlán, C.P., 71230, Oaxaca, Oaxaca, Mexico
| | - Zurisadai Monroy-González
- Centro de Investigación Científica de Yucatán, Unidad de Bioquímica y Biología Molecular de Plantas, Mérida, Yucatán, Mexico
| | - Verónica Borbolla-Pérez
- Centro de Investigación Científica de Yucatán, Unidad de Bioquímica y Biología Molecular de Plantas, Mérida, Yucatán, Mexico
| | - Víctor M Loyola-Vargas
- Centro de Investigación Científica de Yucatán, Unidad de Bioquímica y Biología Molecular de Plantas, Mérida, Yucatán, Mexico.
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Chatterjee P, Schafran P, Li FW, Meeks JC. Nostoc Talks Back: Temporal Patterns of Differential Gene Expression During Establishment of Anthoceros-Nostoc Symbiosis. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2022; 35:917-932. [PMID: 35802132 DOI: 10.1094/mpmi-05-22-0101-r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Endosymbiotic associations between hornworts and nitrogen-fixing cyanobacteria form when the plant is limited for combined nitrogen (N). We generated RNA-seq data to examine temporal gene expression patterns during the culturing of N-starved Anthoceros punctatus in the absence and the presence of symbiotic cyanobacterium Nostoc punctiforme. In symbiont-free A. punctatus gametophytes, N starvation caused downregulation of chlorophyll content and chlorophyll fluorescence characteristics as well as transcription of photosynthesis-related genes. This downregulation was reversed in A. punctatus cocultured with N. punctiforme, corresponding to the provision by the symbiont of N2-derived NH4+, which commenced within 5 days of coculture and reached a maximum by 14 days. We also observed transient increases in transcription of ammonium and nitrate transporters in a N. punctiforme-dependent manner as well as that of a SWEET transporter that was initially independent of N2-derived NH4+. The temporal patterns of differential gene expression indicated that N. punctiforme transmits signals that impact gene expression to A. punctatus both prior to and after its provision of fixed N. This study is the first illustrating the temporal patterns of gene expression during establishment of an endosymbiotic nitrogen-fixing association in this monophyletic evolutionary lineage of land plants. [Formula: see text] Copyright © 2022 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
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Affiliation(s)
- Poulami Chatterjee
- Department of Microbiology and Molecular Genetics, University of California, Davis, CA 95616, U.S.A
| | - Peter Schafran
- Boyce Thompson Institute, Ithaca, NY 14853, U.S.A
- Plant Biology Section, Cornell University, Ithaca, NY 14953, U.S.A
| | - Fay-Wei Li
- Boyce Thompson Institute, Ithaca, NY 14853, U.S.A
- Plant Biology Section, Cornell University, Ithaca, NY 14953, U.S.A
| | - John C Meeks
- Department of Microbiology and Molecular Genetics, University of California, Davis, CA 95616, U.S.A
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Liu Y, Bai L, Sun M, Wang J, Li S, Miao L, Yan Y, He C, Yu X, Li Y. Adaptation of cucumber seedlings to low temperature stress by reducing nitrate to ammonium during it's transportation. BMC PLANT BIOLOGY 2021; 21:189. [PMID: 33874888 PMCID: PMC8056598 DOI: 10.1186/s12870-021-02918-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/11/2020] [Accepted: 03/07/2021] [Indexed: 06/12/2023]
Abstract
BACKGROUND Low temperature severely depresses the uptake, translocation from the root to the shoot, and metabolism of nitrate and ammonium in thermophilic plants such as cucumber (Cucumis sativus). Plant growth is inhibited accordingly. However, the availability of information on the effects of low temperature on nitrogen transport remains limited. RESULTS Using non-invasive micro-test technology, the net nitrate (NO3-) and ammonium (NH4+) fluxes in the root hair zone and vascular bundles of the primary root, stem, petiole, midrib, lateral vein, and shoot tip of cucumber seedlings under normal temperature (NT; 26 °C) and low temperature (LT; 8 °C) treatment were analyzed. Under LT treatment, the net NO3- flux rate in the root hair zone and vascular bundles of cucumber seedlings decreased, whereas the net NH4+ flux rate in vascular bundles of the midrib, lateral vein, and shoot tip increased. Accordingly, the relative expression of CsNRT1.4a in the petiole and midrib was down-regulated, whereas the expression of CsAMT1.2a-1.2c in the midrib was up-regulated. The results of 15N isotope tracing showed that NO3--N and NH4+-N uptake of the seedlings under LT treatment decreased significantly compared with that under NT treatment, and the concentration and proportion of both NO3--N and NH4+-N distributed in the shoot decreased. Under LT treatment, the actual nitrate reductase activity (NRAact) in the root did not change significantly, whereas NRAact in the stem and petiole increased by 113.2 and 96.2%, respectively. CONCLUSIONS The higher net NH4+ flux rate in leaves and young tissues may reflect the higher NRAact in the stem and petiole, which may result in a higher proportion of NO3- being reduced to NH4+ during the upward transportation of NO3-. The results contribute to an improved understanding of the mechanism of changes in nitrate transportation in plants in response to low-temperature stress.
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Affiliation(s)
- Yumei Liu
- The Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, 100081 China
- College of Agricultural and Biological Engineering, Heze University, Heze, 274000 Shandong China
| | - Longqiang Bai
- College of Horticulture, Shanxi Agricultural University, Taigu, 030801 Shanxi China
| | - Mintao Sun
- The Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, 100081 China
| | - Jun Wang
- The Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, 100081 China
| | - Shuzhen Li
- College of Life Science, Gannan Normal University, Ganzhou, 341000 Jiangxi China
| | - Li Miao
- The Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, 100081 China
| | - Yan Yan
- The Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, 100081 China
| | - Chaoxing He
- The Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, 100081 China
| | - Xianchang Yu
- The Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, 100081 China
| | - Yansu Li
- The Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, 100081 China
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10
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Kell DB. A protet-based, protonic charge transfer model of energy coupling in oxidative and photosynthetic phosphorylation. Adv Microb Physiol 2021; 78:1-177. [PMID: 34147184 DOI: 10.1016/bs.ampbs.2021.01.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Textbooks of biochemistry will explain that the otherwise endergonic reactions of ATP synthesis can be driven by the exergonic reactions of respiratory electron transport, and that these two half-reactions are catalyzed by protein complexes embedded in the same, closed membrane. These views are correct. The textbooks also state that, according to the chemiosmotic coupling hypothesis, a (or the) kinetically and thermodynamically competent intermediate linking the two half-reactions is the electrochemical difference of protons that is in equilibrium with that between the two bulk phases that the coupling membrane serves to separate. This gradient consists of a membrane potential term Δψ and a pH gradient term ΔpH, and is known colloquially as the protonmotive force or pmf. Artificial imposition of a pmf can drive phosphorylation, but only if the pmf exceeds some 150-170mV; to achieve in vivo rates the imposed pmf must reach 200mV. The key question then is 'does the pmf generated by electron transport exceed 200mV, or even 170mV?' The possibly surprising answer, from a great many kinds of experiment and sources of evidence, including direct measurements with microelectrodes, indicates it that it does not. Observable pH changes driven by electron transport are real, and they control various processes; however, compensating ion movements restrict the Δψ component to low values. A protet-based model, that I outline here, can account for all the necessary observations, including all of those inconsistent with chemiosmotic coupling, and provides for a variety of testable hypotheses by which it might be refined.
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Affiliation(s)
- Douglas B Kell
- Department of Biochemistry and Systems Biology, Institute of Systems, Molecular and Integrative, Biology, University of Liverpool, Liverpool, United Kingdom; The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Lyngby, Denmark.
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11
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Islam S, Zhang J, Zhao Y, She M, Ma W. Genetic regulation of the traits contributing to wheat nitrogen use efficiency. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2021; 303:110759. [PMID: 33487345 DOI: 10.1016/j.plantsci.2020.110759] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 10/14/2020] [Accepted: 11/11/2020] [Indexed: 05/25/2023]
Abstract
High nitrogen application aimed at increasing crop yield is offset by higher production costs and negative environmental consequences. For wheat, only one third of the applied nitrogen is utilized, which indicates there is scope for increasing Nitrogen Use Efficiency (NUE). However, achieving greater NUE is challenged by the complexity of the trait, which comprises processes associated with nitrogen uptake, transport, reduction, assimilation, translocation and remobilization. Thus, knowledge of the genetic regulation of these processes is critical in increasing NUE. Although primary nitrogen uptake and metabolism-related genes have been well studied, the relative influence of each towards NUE is not fully understood. Recent attention has focused on engineering transcription factors and identification of miRNAs acting on expression of specific genes related to NUE. Knowledge obtained from model species needs to be translated into wheat using recently-released whole genome sequences, and by exploring genetic variations of NUE-related traits in wild relatives and ancient germplasm. Recent findings indicate the genetic basis of NUE is complex. Pyramiding various genes will be the most effective approach to achieve a satisfactory level of NUE in the field.
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Affiliation(s)
- Shahidul Islam
- State Agricultural Biotechnology Center, Murdoch University, Perth, WA, 6150, Australia
| | - Jingjuan Zhang
- State Agricultural Biotechnology Center, Murdoch University, Perth, WA, 6150, Australia
| | - Yun Zhao
- State Agricultural Biotechnology Center, Murdoch University, Perth, WA, 6150, Australia
| | - Maoyun She
- State Agricultural Biotechnology Center, Murdoch University, Perth, WA, 6150, Australia
| | - Wujun Ma
- State Agricultural Biotechnology Center, Murdoch University, Perth, WA, 6150, Australia.
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12
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Cloning and Functional Determination of Ammonium Transporter PpeAMT3;4 in Peach. BIOMED RESEARCH INTERNATIONAL 2020; 2020:2147367. [PMID: 33344631 PMCID: PMC7732375 DOI: 10.1155/2020/2147367] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 11/15/2020] [Accepted: 11/20/2020] [Indexed: 01/29/2023]
Abstract
Ammonium (NH4+) plays key roles in plant growth, development, fruit quality, and yield. In plants, NH4+ uptake and transport are facilitated by NH4+ transporters (AMT). However, molecular mechanisms and physiological functions of type-II AMT (AMT2) transporters in fruit trees are still unclear, especially in peach. In this study, we cloned and characterized an AMT2 family gene from peach, PpeAMT3;4, and determined its function in yeast mutant. Expression analysis showed that PpeAMT3;4 was majorly expressed in peach roots and significantly decreased by NH4+ excess but had no response to NH4+ deficiency. Functional determination and 15nitrogen-labeled NH4+ uptake assay in yeast cells implied that PpeAMT3;4 was a typical high-affinity transporter, with a Km value of 86.3 μM, that can uptake external NH4+ in yeast cells. This study provides gene resources to uncover the biological function of AMT2 transporters and reveals molecular basis for NH4+ uptake and nitrogen (N) nutrition mechanisms in fruit trees.
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13
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Durant AC, Donini A. Ammonium transporter expression in sperm of the disease vector Aedes aegypti mosquito influences male fertility. Proc Natl Acad Sci U S A 2020; 117:29712-29719. [PMID: 33168715 PMCID: PMC7703593 DOI: 10.1073/pnas.2011648117] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The ammonium transporter (AMT)/methylammonium permease (MEP)/Rhesus glycoprotein (Rh) family of ammonia (NH3/NH4+) transporters has been identified in organisms from all domains of life. In animals, fundamental roles for AMT and Rh proteins in the specific transport of ammonia across biological membranes to mitigate ammonia toxicity and aid in osmoregulation, acid-base balance, and excretion have been well documented. Here, we observed enriched Amt (AeAmt1) mRNA levels within reproductive organs of the arboviral vector mosquito, Aedes aegypti, prompting us to explore the role of AMTs in reproduction. We show that AeAmt1 is localized to sperm flagella during all stages of spermiogenesis and spermatogenesis in male testes. AeAmt1 expression in sperm flagella persists in spermatozoa that navigate the female reproductive tract following insemination and are stored within the spermathecae, as well as throughout sperm migration along the spermathecal ducts during ovulation to fertilize the descending egg. We demonstrate that RNA interference (RNAi)-mediated AeAmt1 protein knockdown leads to significant reductions (∼40%) of spermatozoa stored in seminal vesicles of males, resulting in decreased egg viability when these males inseminate nonmated females. We suggest that AeAmt1 function in spermatozoa is to protect against ammonia toxicity based on our observations of high NH4+ levels in the densely packed spermathecae of mated females. The presence of AMT proteins, in addition to Rh proteins, across insect taxa may indicate a conserved function for AMTs in sperm viability and reproduction in general.
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Affiliation(s)
- Andrea C Durant
- Department of Biology, York University, Toronto, ON, Canada M3J 1P3
| | - Andrew Donini
- Department of Biology, York University, Toronto, ON, Canada M3J 1P3
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14
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Grishin D, Kasap E, Izotov A, Lisitsa A. Multifaceted ammonia transporters. ALL LIFE 2020. [DOI: 10.1080/26895293.2020.1812443] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Affiliation(s)
- D.V. Grishin
- Institute of Biomedical Chemistry (IBMC), Moscow, Russia
| | - E.Y. Kasap
- Institute of Biomedical Chemistry (IBMC), Moscow, Russia
| | - A.A. Izotov
- Institute of Biomedical Chemistry (IBMC), Moscow, Russia
| | - A.V. Lisitsa
- Institute of Biomedical Chemistry (IBMC), Moscow, Russia
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15
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Smeulders MJ, Peeters SH, van Alen T, de Bruijckere D, Nuijten GHL, op den Camp HJM, Jetten MSM, van Niftrik L. Nutrient Limitation Causes Differential Expression of Transport- and Metabolism Genes in the Compartmentalized Anammox Bacterium Kuenenia stuttgartiensis. Front Microbiol 2020; 11:1959. [PMID: 32903544 PMCID: PMC7438415 DOI: 10.3389/fmicb.2020.01959] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Accepted: 07/24/2020] [Indexed: 12/11/2022] Open
Abstract
Anaerobic ammonium-oxidizing (anammox) bacteria, members of the "Candidatus Brocadiaceae" family, play an important role in the nitrogen cycle and are estimated to be responsible for about half of the oceanic nitrogen loss to the atmosphere. Anammox bacteria combine ammonium with nitrite and produce dinitrogen gas via the intermediates nitric oxide and hydrazine (anammox reaction) while nitrate is formed as a by-product. These reactions take place in a specialized, membrane-enclosed compartment called the anammoxosome. Therefore, the substrates ammonium, nitrite and product nitrate have to cross the outer-, cytoplasmic-, and anammoxosome membranes to enter or exit the anammoxosome. The genomes of all anammox species harbor multiple copies of ammonium-, nitrite-, and nitrate transporter genes. Here we investigated how the distinct genes for ammonium-, nitrite-, and nitrate- transport were expressed during substrate limitation in membrane bioreactors. Transcriptome analysis of Kuenenia stuttgartiensis planktonic cells showed that four of the seven ammonium transporter homologs and two of the nine nitrite transporter homologs were significantly upregulated during ammonium-limited growth, while another ammonium transporter- and four nitrite transporter homologs were upregulated in nitrite limited growth conditions. The two nitrate transporters were expressed to similar levels in both conditions. In addition, genes encoding enzymes involved in the anammox reaction were differentially expressed, with those using nitrite as a substrate being upregulated under nitrite limited growth and those using ammonium as a substrate being upregulated during ammonium limitation. Taken together, these results give a first insight in the potential role of the multiple nutrient transporters in regulating transport of substrates and products in and out of the compartmentalized anammox cell.
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Affiliation(s)
| | | | | | | | | | | | | | - Laura van Niftrik
- Department of Microbiology, Institute for Water and Wetland Research, Faculty of Science, Radboud University Nijmegen, Nijmegen, Netherlands
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16
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Williamson G, Tamburrino G, Bizior A, Boeckstaens M, Dias Mirandela G, Bage MG, Pisliakov A, Ives CM, Terras E, Hoskisson PA, Marini AM, Zachariae U, Javelle A. A two-lane mechanism for selective biological ammonium transport. eLife 2020; 9:57183. [PMID: 32662768 PMCID: PMC7447429 DOI: 10.7554/elife.57183] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Accepted: 07/13/2020] [Indexed: 11/13/2022] Open
Abstract
The transport of charged molecules across biological membranes faces the dual problem of accommodating charges in a highly hydrophobic environment while maintaining selective substrate translocation. This has been the subject of a particular controversy for the exchange of ammonium across cellular membranes, an essential process in all domains of life. Ammonium transport is mediated by the ubiquitous Amt/Mep/Rh transporters that includes the human Rhesus factors. Here, using a combination of electrophysiology, yeast functional complementation and extended molecular dynamics simulations, we reveal a unique two-lane pathway for electrogenic NH4+ transport in two archetypal members of the family, the transporters AmtB from Escherichia coli and Rh50 from Nitrosomonas europaea. The pathway underpins a mechanism by which charged H+ and neutral NH3 are carried separately across the membrane after NH4+ deprotonation. This mechanism defines a new principle of achieving transport selectivity against competing ions in a biological transport process.
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Affiliation(s)
- Gordon Williamson
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, United Kingdom
| | - Giulia Tamburrino
- Computational Biology, School of Life Sciences, University of Dundee, Dundee, United Kingdom.,Physics, School of Science and Engineering, University of Dundee, Dundee, United Kingdom
| | - Adriana Bizior
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, United Kingdom
| | - Mélanie Boeckstaens
- Biology of Membrane Transport Laboratory, Department of Molecular Biology, Université Libre de Bruxelles, Gosselies, Belgium
| | - Gaëtan Dias Mirandela
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, United Kingdom
| | - Marcus G Bage
- Computational Biology, School of Life Sciences, University of Dundee, Dundee, United Kingdom.,Physics, School of Science and Engineering, University of Dundee, Dundee, United Kingdom
| | - Andrei Pisliakov
- Computational Biology, School of Life Sciences, University of Dundee, Dundee, United Kingdom.,Physics, School of Science and Engineering, University of Dundee, Dundee, United Kingdom
| | - Callum M Ives
- Computational Biology, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Eilidh Terras
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, United Kingdom
| | - Paul A Hoskisson
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, United Kingdom
| | - Anna Maria Marini
- Biology of Membrane Transport Laboratory, Department of Molecular Biology, Université Libre de Bruxelles, Gosselies, Belgium
| | - Ulrich Zachariae
- Computational Biology, School of Life Sciences, University of Dundee, Dundee, United Kingdom.,Physics, School of Science and Engineering, University of Dundee, Dundee, United Kingdom
| | - Arnaud Javelle
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, United Kingdom
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17
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Hao DL, Zhou JY, Yang SY, Qi W, Yang KJ, Su YH. Function and Regulation of Ammonium Transporters in Plants. Int J Mol Sci 2020; 21:E3557. [PMID: 32443561 PMCID: PMC7279009 DOI: 10.3390/ijms21103557] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2020] [Revised: 05/11/2020] [Accepted: 05/13/2020] [Indexed: 02/07/2023] Open
Abstract
Ammonium transporter (AMT)-mediated acquisition of ammonium nitrogen from soils is essential for the nitrogen demand of plants, especially for those plants growing in flooded or acidic soils where ammonium is dominant. Recent advances show that AMTs additionally participate in many other physiological processes such as transporting ammonium from symbiotic fungi to plants, transporting ammonium from roots to shoots, transferring ammonium in leaves and reproductive organs, or facilitating resistance to plant diseases via ammonium transport. Besides being a transporter, several AMTs are required for the root development upon ammonium exposure. To avoid the adverse effects of inadequate or excessive intake of ammonium nitrogen on plant growth and development, activities of AMTs are fine-tuned not only at the transcriptional level by the participation of at least four transcription factors, but also at protein level by phosphorylation, pH, endocytosis, and heterotrimerization. Despite these progresses, it is worth noting that stronger growth inhibition, not facilitation, unfortunately occurs when AMT overexpression lines are exposed to optimal or slightly excessive ammonium. This implies that a long road remains towards overcoming potential limiting factors and achieving AMT-facilitated yield increase to accomplish the goal of persistent yield increase under the present high nitrogen input mode in agriculture.
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Affiliation(s)
- Dong-Li Hao
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; (D.-L.H.); (J.-Y.Z.); (S.-Y.Y.)
| | - Jin-Yan Zhou
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; (D.-L.H.); (J.-Y.Z.); (S.-Y.Y.)
| | - Shun-Ying Yang
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; (D.-L.H.); (J.-Y.Z.); (S.-Y.Y.)
| | - Wei Qi
- College of Resources and Environment, Shandong Agricultural University, Taian 271018, China;
| | - Ke-Jun Yang
- Agro-Tech Extension and Service Center, Zhucheng 262200, China;
| | - Yan-Hua Su
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; (D.-L.H.); (J.-Y.Z.); (S.-Y.Y.)
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18
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Roy R, Reinders A, Ward JM, McDonald TR. Understanding transport processes in lichen, Azolla-cyanobacteria, ectomycorrhiza, endomycorrhiza, and rhizobia-legume symbiotic interactions. F1000Res 2020; 9. [PMID: 32047609 PMCID: PMC6979478 DOI: 10.12688/f1000research.19740.1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 01/16/2020] [Indexed: 12/20/2022] Open
Abstract
Intimate interactions between photosynthetic and non-photosynthetic organisms require the orchestrated transfer of ions and metabolites between species. We review recent progress in identifying and characterizing the transport proteins involved in five mutualistic symbiotic interactions: lichens,
Azolla–cyanobacteria, ectomycorrhiza, endomycorrhiza, and rhizobia–legumes. This review focuses on transporters for nitrogen and carbon and other solutes exchanged in the interactions. Their predicted functions are evaluated on the basis of their transport mechanism and prevailing transmembrane gradients of H
+ and transported substrates. The symbiotic interactions are presented in the assumed order from oldest to most recently evolved.
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Affiliation(s)
- Rahul Roy
- Department of Plant and Microbial Biology, University of Minnesota, Minnesota, USA
| | - Anke Reinders
- College of Continuing and Professional Studies, University of Minnesota, Minnesota, USA
| | - John M Ward
- Department of Plant and Microbial Biology, University of Minnesota, Minnesota, USA
| | - Tami R McDonald
- Biology Department, St. Catherine University, Minnesota, USA
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19
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Zhu Y, Huang X, Hao Y, Su W, Liu H, Sun G, Chen R, Song S. Ammonium Transporter ( BcAMT1.2) Mediates the Interaction of Ammonium and Nitrate in Brassica campestris. FRONTIERS IN PLANT SCIENCE 2020; 10:1776. [PMID: 32117342 PMCID: PMC7011105 DOI: 10.3389/fpls.2019.01776] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Accepted: 12/19/2019] [Indexed: 06/01/2023]
Abstract
The provision of ammonium (NH4 +) and nitrate (NO3 -) mixture increases the total nitrogen (N) than the supply of sole NH4 + or NO3 - with the same concentration of total N; thus, the mixture contributes to better growth in Brassica campestris. However, the underlying mechanisms remain unknown. In this study, we analyzed NH4 + and NO3 - fluxes using a scanning ion-selective electrode technique to detect under different N forms and levels in B. campestris roots. We observed that the total N influxes with NH4 + and NO3 - mixture were 1.25- and 3.53-fold higher than those with either sole NH4 + or NO3 -. Furthermore, NH4 + and NO3 - might interact with each other under coexistence. NO3 - had a positive effect on net NH4 + influx, whereas NH4 + had a negative influence on net NO3 - influx. The ammonium transporter (AMT) played a key role in NH4 + absorption and transport. Based on expression analysis, BcAMT1.2 differed from other BcAMT1s in being upregulated by NH4 + or NO3 -. According to sequence analysis and functional complementation in yeast mutant 31019b, AMT1.2 from B. campestris may be a functional AMT. According to the expression pattern of BcAMT1.2, β-glucuronidase activity, and the cellular location of its promoter, BcAMT1.2 may be responsible for NH4 + transport. Following the overexpression of BcAMT1.2 in Arabidopsis, BcAMT1.2-overexpressing lines grew better than wildtype lines at low NH4 + concentration. In the mixture of NH4 + and NO3 -, NH4 + influxes and NO3 - effluxes were induced in BcAMT1.2-overexpressing lines. Furthermore, transcripts of N assimilation genes (AtGLN1.2, AtGLN2, and AtGLT1) were significantly upregulated, in particular, AtGLN1.2 and AtGLT1 were increased by 2.85-8.88 times in roots, and AtGLN1.2 and AtGLN2 were increased by 2.67-4.61 times in leaves. Collectively, these results indicated that BcAMT1.2 may mediate in NH4 + fluxes under the coexistence of NH4 + and NO3 - in B. campestris.
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Affiliation(s)
- Yunna Zhu
- College of Horticulture, South China Agricultural University, Guangzhou, China
- College of Yingdong Agricultural Science and Engineering, Shaoguan University, Shaoguan, China
| | - Xinmin Huang
- College of Horticulture, South China Agricultural University, Guangzhou, China
| | - Yanwei Hao
- College of Horticulture, South China Agricultural University, Guangzhou, China
| | - Wei Su
- College of Horticulture, South China Agricultural University, Guangzhou, China
| | - Houcheng Liu
- College of Horticulture, South China Agricultural University, Guangzhou, China
| | - Guangwen Sun
- College of Horticulture, South China Agricultural University, Guangzhou, China
| | - Riyuan Chen
- College of Horticulture, South China Agricultural University, Guangzhou, China
| | - Shiwei Song
- College of Horticulture, South China Agricultural University, Guangzhou, China
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20
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Hao DL, Yang SY, Liu SX, Zhou JY, Huang YN, Véry AA, Sentenac H, Su YH. Functional Characterization of the Arabidopsis Ammonium Transporter AtAMT1;3 With the Emphasis on Structural Determinants of Substrate Binding and Permeation Properties. FRONTIERS IN PLANT SCIENCE 2020; 11:571. [PMID: 32528489 PMCID: PMC7256485 DOI: 10.3389/fpls.2020.00571] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Accepted: 04/17/2020] [Indexed: 05/13/2023]
Abstract
AtAMT1;3 is a major contributor to high-affinity ammonium uptake in Arabidopsis roots. Using a stable electrophysiological recording strategy, we demonstrate in Xenopus laevis oocytes that AtAMT1;3 functions as a typical high-affinity NH4 + uniporter independent of protons and Ca2+. The findings that AtAMT1;3 transports methylammonium (MeA+, a chemical analog of NH4 +) with extremely low affinity (K m in the range of 2.9-6.1 mM) led to investigate the mechanisms underlying substrate binding. Homologous modeling and substrate docking analyses predicted that the deduced substrate binding motif of AtAMT1;3 facilitates the binding of NH4 + ions but loosely accommodates the binding of MeA+ to a more superficial location of the permeation pathway. Amongst point mutations tested based on this analysis, P181A resulted in both significantly increased current amplitudes and substrate binding affinity, whereas F178I led to opposite effects. Thus these 2 residues, which flank W179, a major structural component of the binding site, are also important determinants of AtAMT1;3 transport capacity by being involved in substrate binding. The Q365K mutation neighboring the histidine residue H378, which confines the substrate permeation tunnel, affected only the current amplitudes but not the binding affinities, providing evidence that Q365 mainly controls the substrate diffusion rate within the permeation pathway.
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Affiliation(s)
- Dong-Li Hao
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, China
| | - Shun-Ying Yang
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, China
| | - Shu-Xia Liu
- Department of Computational Biology, Beijing Computing Center, Beijing, China
| | - Jin-Yan Zhou
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, China
| | - Ya-Nan Huang
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, China
| | - Anne-Aliénor Véry
- BPMP, Univ Montpellier, CNRS, INRAE, Institut Agro, Montpellier, France
| | - Hervé Sentenac
- BPMP, Univ Montpellier, CNRS, INRAE, Institut Agro, Montpellier, France
- *Correspondence: Hervé Sentenac,
| | - Yan-Hua Su
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, China
- Yan-Hua Su,
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21
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Mirandela GD, Tamburrino G, Hoskisson PA, Zachariae U, Javelle A. The lipid environment determines the activity of the Escherichia coli ammonium transporter AmtB. FASEB J 2018; 33:1989-1999. [PMID: 30211659 PMCID: PMC6338640 DOI: 10.1096/fj.201800782r] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The movement of ammonium across biologic membranes is a fundamental process in all living organisms and is mediated by the ubiquitous ammonium transporter/methylammonium permease/rhesus protein (Amt/Mep/Rh) family of transporters. Recent structural analysis and coupled mass spectrometry studies have shown that the Escherichia coli ammonium transporter AmtB specifically binds 1-palmitoyl-2-oleoyl phosphatidylglycerol (POPG). Upon POPG binding, several residues of AmtB undergo a small conformational change, which stabilizes the protein against unfolding. However, no studies have so far been conducted, to our knowledge, to explore whether POPG binding to AmtB has functional consequences. Here, we used an in vitro experimental assay with purified components, together with molecular dynamics simulations, to characterize the relation between POPG binding and AmtB activity. We show that the AmtB activity is electrogenic. Our results indicate that the activity, at the molecular level, of Amt in archaebacteria and eubacteria may differ. We also show that POPG is an important cofactor for AmtB activity and that, in the absence of POPG, AmtB cannot complete the full translocation cycle. Furthermore, our simulations reveal previously undiscovered POPG binding sites on the intracellular side of the lipid bilayer between the AmtB subunits. Possible molecular mechanisms explaining the functional role of POPG are discussed.-Mirandela, G. D., Tamburrino, G., Hoskisson, P. A., Zachariae, U., Javelle, A. The lipid environment determines the activity of the Escherichia coli ammonium transporter AmtB.
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Affiliation(s)
- Gaëtan Dias Mirandela
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, United Kingdom
| | - Giulia Tamburrino
- Computational Biology, School of Life Sciences, University of Dundee, Dundee, United Kingdom.,Physics, School of Science and Engineering, University of Dundee, Dundee, United Kingdom
| | - Paul A Hoskisson
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, United Kingdom
| | - Ulrich Zachariae
- Computational Biology, School of Life Sciences, University of Dundee, Dundee, United Kingdom.,Physics, School of Science and Engineering, University of Dundee, Dundee, United Kingdom
| | - Arnaud Javelle
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, United Kingdom
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22
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Ariz I, Boeckstaens M, Gouveia C, Martins AP, Sanz-Luque E, Fernández E, Soveral G, von Wirén N, Marini AM, Aparicio-Tejo PM, Cruz C. Nitrogen isotope signature evidences ammonium deprotonation as a common transport mechanism for the AMT-Mep-Rh protein superfamily. SCIENCE ADVANCES 2018; 4:eaar3599. [PMID: 30214933 PMCID: PMC6135547 DOI: 10.1126/sciadv.aar3599] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Accepted: 07/27/2018] [Indexed: 06/08/2023]
Abstract
Ammonium is an important nitrogen (N) source for living organisms, a key metabolite for pH control, and a potent cytotoxic compound. Ammonium is transported by the widespread AMT-Mep-Rh membrane proteins, and despite their significance in physiological processes, the nature of substrate translocation (NH3/NH4+) by the distinct members of this family is still a matter of controversy. Using Saccharomyces cerevisiae cells expressing representative AMT-Mep-Rh ammonium carriers and taking advantage of the natural chemical-physical property of the N isotopic signature linked to NH4+/NH3 conversion, this study shows that only cells expressing AMT-Mep-Rh proteins were depleted in 15N relative to 14N when compared to the external ammonium source. We observed 15N depletion over a wide range of external pH, indicating its independence of NH3 formation in solution. On the basis of inhibitor studies, ammonium transport by nonspecific cation channels did not show isotope fractionation but competition with K+. We propose that kinetic N isotope fractionation is a common feature of AMT-Mep-Rh-type proteins, which favor 14N over 15N, owing to the dissociation of NH4+ into NH3 + H+ in the protein, leading to 15N depletion in the cell and allowing NH3 passage or NH3/H+ cotransport. This deprotonation mechanism explains these proteins' essential functions in environments under a low NH4+/K+ ratio, allowing organisms to specifically scavenge NH4+. We show that 15N isotope fractionation may be used in vivo not only to determine the molecular species being transported by ammonium transport proteins, but also to track ammonium toxicity and associated amino acids excretion.
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Affiliation(s)
- Idoia Ariz
- Centre for Ecology, Evolution and Environmental Changes, Faculdade de Ciências da Universidade de Lisboa, 1749-016 Lisboa, Portugal
| | - Mélanie Boeckstaens
- Biology of Membrane Transport, Department of Molecular Biology, Université Libre de Bruxelles, 6041 Gosselies, Belgium
| | - Catarina Gouveia
- Centre for Ecology, Evolution and Environmental Changes, Faculdade de Ciências da Universidade de Lisboa, 1749-016 Lisboa, Portugal
| | - Ana Paula Martins
- iMed.ULisboa–Research Institute for Medicines, Faculdade de Farmácia da Universidade de Lisboa, 1649-003 Lisboa, Portugal
| | - Emanuel Sanz-Luque
- Department of Biochemistry and Molecular Biology, Univeristy of Córdoba, 14071 Cordoba, Spain
| | - Emilio Fernández
- Department of Biochemistry and Molecular Biology, Univeristy of Córdoba, 14071 Cordoba, Spain
| | - Graça Soveral
- iMed.ULisboa–Research Institute for Medicines, Faculdade de Farmácia da Universidade de Lisboa, 1649-003 Lisboa, Portugal
| | - Nicolaus von Wirén
- Department of Physiology and Cell Biology, Leibniz Institute for Plant Genetics and Crop Plant Research, Seeland, 06466 OT Gatersleben, Germany
| | - Anna M. Marini
- Biology of Membrane Transport, Department of Molecular Biology, Université Libre de Bruxelles, 6041 Gosselies, Belgium
| | | | - Cristina Cruz
- Centre for Ecology, Evolution and Environmental Changes, Faculdade de Ciências da Universidade de Lisboa, 1749-016 Lisboa, Portugal
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23
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Guo H, Wang N, McDonald TR, Reinders A, Ward JM. MpAMT1;2 from Marchantia polymorpha is a High-Affinity, Plasma Membrane Ammonium Transporter. PLANT & CELL PHYSIOLOGY 2018; 59:997-1005. [PMID: 29444306 DOI: 10.1093/pcp/pcy038] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Accepted: 02/09/2018] [Indexed: 06/08/2023]
Abstract
Plant ammonium transporters in the AMT/MEP/Rh (ammonium transporter/methylammonium and ammonium permease/Rhesus factor) superfamily have only been previously characterized in flowering plants (angiosperms). Plant AMT1s are electrogenic, while plant AMT2s are electroneutral, and MEP and Rh transporters in other organisms are electroneutral. We analyzed the transport function of MpAMT1;2 from the basal land plant Marchantia polymorpha, a liverwort. MpAMT1;2 was shown to localize to the plasma membrane in Marchantia gametophyte thallus by stable transformation using a C-terminal citrine fusion. MpAMT1;2 expression was studied using quantitative real-time PCR and shown to be higher when plants were N deficient and lower when plants were grown on media containing ammonium, nitrate or the amino acid glutamine. Expression in Xenopus oocytes and analysis by electrophysiology revealed that MpAMT1;2 is an electrogenic ammonium transporter with a very high affinity for ammonium (7 µM at pH 5.6 and a membrane potential of -137 mV). A conserved inhibitory phosphorylation site identified in angiosperm AMT1s is also present in all AMT1s in Marchantia. Here we show that a phosphomimetic mutation T475D in MpAMT1;2 completely inhibits ammonium transport activity. The results indicate that MpAMT1;2 may be important for ammonium uptake into cells in the Marchantia thallus.
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Affiliation(s)
- Hanqing Guo
- Department of Plant and Microbial Biology, University of Minnesota Twin Cities, St. Paul, MN, USA
| | - Nu Wang
- Department of Plant and Microbial Biology, University of Minnesota Twin Cities, St. Paul, MN, USA
| | - Tami R McDonald
- Biology Department, St. Catherine University, St. Paul, MN, USA
| | - Anke Reinders
- Department of Plant and Microbial Biology, University of Minnesota Twin Cities, St. Paul, MN, USA
| | - John M Ward
- Department of Plant and Microbial Biology, University of Minnesota Twin Cities, St. Paul, MN, USA
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24
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Durant AC, Donini A. Ammonia Excretion in an Osmoregulatory Syncytium Is Facilitated by AeAmt2, a Novel Ammonia Transporter in Aedes aegypti Larvae. Front Physiol 2018; 9:339. [PMID: 29695971 PMCID: PMC5905399 DOI: 10.3389/fphys.2018.00339] [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: 11/29/2017] [Accepted: 03/20/2018] [Indexed: 02/03/2023] Open
Abstract
The larvae of the mosquito Aedes aegypti inhabit ammonia rich septic tanks in tropical regions of the world that make extensive use of these systems, explaining the prevalence of disease during dry seasons. Since ammonia (NH3/NH4+) is toxic to animals, an understanding of the physiological mechanisms of ammonia excretion permitting the survival of A. aegypti larvae in high ammonia environments is important. We have characterized a novel ammonia transporter, AeAmt2, belonging to the Amt/MEP/Rh family of ammonia transporters. Based on the amino acid sequence, the predicted topology of AeAmt2 consists of 11 transmembrane helices with an extracellular N-terminus and a cytoplasmic C-terminus region. Alignment of the predicted AeAmt2 amino acid sequence with other Amt/MEP proteins from plants, bacteria, and yeast highlights the presence of conserved residues characteristic of ammonia conducting channels in this protein. AeAmt2 is expressed in the ionoregulatory anal papillae of A. aegypti larvae where it is localized to the apical membrane of the epithelium. dsRNA-mediated knockdown of AeAmt2 results in a significant decrease in NH4+ efflux from the anal papillae, suggesting a key role in facilitating ammonia excretion. The effect of high environmental ammonia (HEA) on expression of AeAmt2, along with previously characterized AeAmt1, AeRh50-1, and AeRh50-2 in the anal papillae was investigated. We show that changes in expression of ammonia transporters occur in response to acute and chronic exposure to HEA, which reflects the importance of these transporters in the physiology of life in high ammonia habitats.
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Affiliation(s)
| | - Andrew Donini
- Department of Biology, York University, Toronto, ON, Canada
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25
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Liu LH, Fan TF, Shi DX, Li CJ, He MJ, Chen YY, Zhang L, Yang C, Cheng XY, Chen X, Li DQ, Sun YC. Coding-Sequence Identification and Transcriptional Profiling of Nine AMTs and Four NRTs From Tobacco Revealed Their Differential Regulation by Developmental Stages, Nitrogen Nutrition, and Photoperiod. FRONTIERS IN PLANT SCIENCE 2018; 9:210. [PMID: 29563921 PMCID: PMC5850829 DOI: 10.3389/fpls.2018.00210] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Accepted: 02/05/2018] [Indexed: 05/31/2023]
Abstract
Although many members encoding different ammonium- and nitrate-transporters (AMTs, NRTs) were identified and functionally characterized from several plant species, little is known about molecular components for [Formula: see text]- and [Formula: see text] acquisition/transport in tobacco, which is often used as a plant model for biological studies besides its agricultural and industrial interest. We reported here the first molecular identification in tobacco (Nicotiana tabacum) of nine AMTs and four NRTs, which are respectively divided into four (AMT1/2/3/4) and two (NRT1/2) clusters and whose functionalities were preliminarily evidenced by heterologous functional-complementation in yeast or Arabidopsis. Tissue-specific transcriptional profiling by qPCR revealed that NtAMT1.1/NRT1.1 mRNA occurred widely in leaves, flower organs and roots; only NtAMT1.1/1.3/2.1NRT1.2/2.2 were strongly transcribed in the aged leaves, implying their dominant roles in N-remobilization from source/senescent tissues. N-dependent expression analysis showed a marked upregulation of NtAMT1.1 in the roots by N-starvation and resupply with N including [Formula: see text], suggesting a predominant action of NtAMT1.1 in [Formula: see text] uptake/transport whenever required. The obvious leaf-expression of other NtAMTs e.g., AMT1.2 responsive to N indicates a major place, where they may play transport roles associated with plant N-status and ([Formula: see text]-)N movement within aerial-parts. The preferentially root-specific transcription of NtNRT1.1/1.2/2.1 responsive to N argues their importance for root [Formula: see text] uptake and even sensing in root systems. Moreover, of all NtAMTs/NRTs, only NtAMT1.1/NRT1.1/1.2 showed their root-expression alteration in a typical diurnal-oscillation pattern, reflecting likely their significant roles in root N-acquisition regulated by internal N-demand influenced by diurnal-dependent assimilation and translocation of carbohydrates from shoots. This suggestion could be supported at least in part by sucrose- and MSX-affected transcriptional-regulation of NtNRT1.1/1.2. Thus, present data provide valuable molecular bases for the existence of AMTs/NRTs in tobacco, promoting a deeper understanding of their biological functions.
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Affiliation(s)
- Lai-Hua Liu
- Department of Crop Breeding, College of Agriculture Sciences Hunan Agricultural University, Changsha, China
- Department of Plant Nutrition, College of Resources and Environmental Sciences China Agricultural University, Beijing, China
| | - Teng-Fei Fan
- Department of Plant Nutrition, College of Resources and Environmental Sciences China Agricultural University, Beijing, China
| | - Dong-Xue Shi
- Department of Plant Nutrition, College of Resources and Environmental Sciences China Agricultural University, Beijing, China
| | - Chang-Jun Li
- Institute of Tobacco Research of Chongqing Tobacco Company China Tobacco Corporation, Chongqing, China
| | - Ming-Jie He
- Department of Crop Breeding, College of Agriculture Sciences Hunan Agricultural University, Changsha, China
| | - Yi-Yin Chen
- Institute of Tobacco Research of Chongqing Tobacco Company China Tobacco Corporation, Chongqing, China
| | - Lei Zhang
- Department of Plant Nutrition, College of Resources and Environmental Sciences China Agricultural University, Beijing, China
| | - Chao Yang
- Institute of Tobacco Research of Chongqing Tobacco Company China Tobacco Corporation, Chongqing, China
| | - Xiao-Yuan Cheng
- Department of Plant Nutrition, College of Resources and Environmental Sciences China Agricultural University, Beijing, China
| | - Xu Chen
- Institute of Tobacco Research of Chongqing Tobacco Company China Tobacco Corporation, Chongqing, China
| | - Di-Qin Li
- Department of Crop Breeding, College of Agriculture Sciences Hunan Agricultural University, Changsha, China
| | - Yi-Chen Sun
- Department of Plant Nutrition, College of Resources and Environmental Sciences China Agricultural University, Beijing, China
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26
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Weihrauch D, Allen GJP. Ammonia excretion in aquatic invertebrates: new insights and questions. J Exp Biol 2018; 221:221/2/jeb169219. [DOI: 10.1242/jeb.169219] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
ABSTRACT
Invertebrates employ a variety of ammonia excretion strategies to facilitate their survival in diverse aquatic environments, including freshwater, seawater and the water film surrounding soil particles. Various environmental properties set innate challenges for an organism's ammonia excretory capacity. These include the availability of NaCl and the respective ion-permeability of the organism's transport epithelia, and the buffering capacity of their immediate surrounding medium. To this end, some transporters seem to be conserved in the excretory process. This includes the Na+/K+(NH4+)-ATPase (NKA), the NH3/CO2 dual gas-channel Rhesus (Rh)-proteins and novel ammonia transporters (AMTs), which have been identified in several invertebrates but appear to be absent from vertebrates. In addition, recent evidence strongly suggests that the hyperpolarization-activated cyclic nucleotide-gated K+ channel (HCN) plays a significant role in ammonia excretion and is highly conserved throughout the animal kingdom. Furthermore, microtubule-dependent vesicular excretion pathways have been found in marine and soil-dwelling species, where, unlike freshwater systems, acid-trapping of excreted ammonia is difficult or absent owing to the high environmental buffering capacity of the surroundings. Finally, although ammonia is known to be a toxic nitrogenous waste product, certain marine species readily maintain potentially toxic hemolymph ammonia as a sort of ammonia homeostasis, which suggests that ammonia is involved in physiological processes and does not exist simply for excretion. Such findings are discussed within this Commentary and are hypothesized to be involved in acid–base regulation. We also describe excretory organs and processes that are dependent on environmental constraints and indicate gaps in the current knowledge in these topics.
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Affiliation(s)
- Dirk Weihrauch
- University of Manitoba, Department of Biological Sciences, Winnipeg, R3T2N2, MB, Canada
| | - Garett J. P. Allen
- University of Manitoba, Department of Biological Sciences, Winnipeg, R3T2N2, MB, Canada
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27
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Fan TF, Cheng XY, Shi DX, He MJ, Yang C, Liu L, Li CJ, Sun YC, Chen YY, Xu C, Zhang L, Liu LH. Molecular identification of tobacco NtAMT1.3 that mediated ammonium root-influx with high affinity and improved plant growth on ammonium when overexpressed in Arabidopsis and tobacco. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2017; 264:102-111. [PMID: 28969790 DOI: 10.1016/j.plantsci.2017.09.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2017] [Revised: 09/06/2017] [Accepted: 09/07/2017] [Indexed: 06/07/2023]
Abstract
Although biological functions of ammonium (NH4+) transporters (AMTs) have been intensively studied in many plant species, little is known about molecular bases responsible for NH4+ movement in tobacco. Here, we reported the identification and functional characterization of a putative NH4+ transporter NtAMT1.3 from tobacco (Nicotiana tabacum). Analysis in silico showed that NtAMT1.3 encoded an integral membrane protein containing 464 amino acid residues and exhibiting 10 predicted transmembrane α-helices. Heterologous functionality study demonstrated that NtAMT1.3 expression facilitated NH4+ entry across plasma membrane of NH4+-uptake defective yeast and Arabidopsis qko mutant, allowing a restored growth of both yeast and Arabidopsis mutant on low NH4+. qPCR assay revealed that NtAMT1.3 was expressed in both roots and leaves and significantly up-regulated by nitrogen starvation and resupply of its putative substrate NH4+ and even nitrate, suggesting that NtAMT1.3 should represent a nitrogen-responsive gene. Critically, constitutive overexpression of NtAMT1.3 in tobacco per se improved obviously the growth of transgenic plants on NH4+ and enhanced leaf nitrogen (15% more) accumulation, consistent with observation of 35% more NH4+ uptake by the roots of transgenic lines in 20min root-influx test. Together with data showing its plasma membrane localization and saturated transport nature with Km of about 50μM for NH4+, we suggest that NtAMT1.3 acts an active NH4+ transporter that plays a significant role in NH4+ acquisition and utilization in tobacco.
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Affiliation(s)
- Teng-Fei Fan
- Department of Plant Nutrition, College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China; Institute of Tobacco Science Research of Chongqing Tobacco Company, China Tobacco Corporation, Chongqing 400716, China
| | - Xiao-Yuan Cheng
- Department of Plant Nutrition, College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China
| | - Dong-Xue Shi
- Department of Plant Nutrition, College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China
| | - Ming-Jie He
- Department of Plant Nutrition, College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China; College of Agriculture Sciences, Hunan Agricultural University, Changsha 410128, China
| | - Chao Yang
- Institute of Tobacco Science Research of Chongqing Tobacco Company, China Tobacco Corporation, Chongqing 400716, China
| | - Lu Liu
- Department of Plant Nutrition, College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China
| | - Chang-Jun Li
- Institute of Tobacco Science Research of Chongqing Tobacco Company, China Tobacco Corporation, Chongqing 400716, China
| | - Yi-Chen Sun
- Department of Plant Nutrition, College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China
| | - Yi-Yin Chen
- Institute of Tobacco Science Research of Chongqing Tobacco Company, China Tobacco Corporation, Chongqing 400716, China
| | - Chen Xu
- Institute of Tobacco Science Research of Chongqing Tobacco Company, China Tobacco Corporation, Chongqing 400716, China
| | - Lei Zhang
- Department of Plant Nutrition, College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China
| | - Lai-Hua Liu
- Department of Plant Nutrition, College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China.
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28
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Brouwer P, Bräutigam A, Buijs VA, Tazelaar AOE, van der Werf A, Schlüter U, Reichart GJ, Bolger A, Usadel B, Weber APM, Schluepmann H. Metabolic Adaptation, a Specialized Leaf Organ Structure and Vascular Responses to Diurnal N 2 Fixation by Nostoc azollae Sustain the Astonishing Productivity of Azolla Ferns without Nitrogen Fertilizer. FRONTIERS IN PLANT SCIENCE 2017; 8:442. [PMID: 28408911 PMCID: PMC5374210 DOI: 10.3389/fpls.2017.00442] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Accepted: 03/14/2017] [Indexed: 05/02/2023]
Abstract
Sustainable agriculture demands reduced input of man-made nitrogen (N) fertilizer, yet N2 fixation limits the productivity of crops with heterotrophic diazotrophic bacterial symbionts. We investigated floating ferns from the genus Azolla that host phototrophic diazotrophic Nostoc azollae in leaf pockets and belong to the fastest growing plants. Experimental production reported here demonstrated N-fertilizer independent production of nitrogen-rich biomass with an annual yield potential per ha of 1200 kg-1 N fixed and 35 t dry biomass. 15N2 fixation peaked at noon, reaching 0.4 mg N g-1 dry weight h-1. Azolla ferns therefore merit consideration as protein crops in spite of the fact that little is known about the fern's physiology to enable domestication. To gain an understanding of their nitrogen physiology, analyses of fern diel transcript profiles under differing nitrogen fertilizer regimes were combined with microscopic observations. Results established that the ferns adapted to the phototrophic N2-fixing symbionts N. azollae by (1) adjusting metabolically to nightly absence of N supply using responses ancestral to ferns and seed plants; (2) developing a specialized xylem-rich vasculature surrounding the leaf-pocket organ; (3) responding to N-supply by controlling transcripts of genes mediating nutrient transport, allocation and vasculature development. Unlike other non-seed plants, the Azolla fern clock is shown to contain both the morning and evening loops; the evening loop is known to control rhythmic gene expression in the vasculature of seed plants and therefore may have evolved along with the vasculature in the ancestor of ferns and seed plants.
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Affiliation(s)
- Paul Brouwer
- Molecular Plant Physiology, Institute of Environmental Biology, Utrecht UniversityUtrecht, Netherlands
| | - Andrea Bräutigam
- Institute for Plant Biochemistry, Cluster of Excellence on Plant Sciences, Heinrich Heine UniversityDüsseldorf, Germany
| | - Valerie A. Buijs
- Molecular Plant Physiology, Institute of Environmental Biology, Utrecht UniversityUtrecht, Netherlands
| | - Anne O. E. Tazelaar
- Molecular Plant Physiology, Institute of Environmental Biology, Utrecht UniversityUtrecht, Netherlands
| | | | - Urte Schlüter
- Institute for Plant Biochemistry, Cluster of Excellence on Plant Sciences, Heinrich Heine UniversityDüsseldorf, Germany
| | | | - Anthony Bolger
- Institute for Botany and Molecular Genetics, Bioeconomy Science Center, RWTH Aachen UniversityAachen, Germany
| | - Björn Usadel
- Institute for Botany and Molecular Genetics, Bioeconomy Science Center, RWTH Aachen UniversityAachen, Germany
| | - Andreas P. M. Weber
- Institute for Plant Biochemistry, Cluster of Excellence on Plant Sciences, Heinrich Heine UniversityDüsseldorf, Germany
| | - Henriette Schluepmann
- Molecular Plant Physiology, Institute of Environmental Biology, Utrecht UniversityUtrecht, Netherlands
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