1
|
Su Y. Revisiting carbon, nitrogen, and phosphorus metabolisms in microalgae for wastewater treatment. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 762:144590. [PMID: 33360454 DOI: 10.1016/j.scitotenv.2020.144590] [Citation(s) in RCA: 136] [Impact Index Per Article: 45.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2020] [Revised: 12/10/2020] [Accepted: 12/12/2020] [Indexed: 05/05/2023]
Abstract
Threats posed to humans - including environmental pollution, water scarcity, food shortages, and resource crises drive a new concept to think about wastewater and its treatment. Wastewater is not only a waste but also a source of energy, renewable and/or non-renewable resources, including water itself. The nutrient in wastewater should not only be removed but also need to be upcycled. Microalgae based wastewater treatment has attracted considerable interests because algae have the potential to efficiently redirect nutrients from wastewater to the accumulated algal biomass. Additionally, microalgae are commercialized in human consumption and animal feed owing to their high content of essential amino and fatty acids, vitamins, and pigments. The whole process establishes a circular economy, totally relying on the ability of microalgae to uptake and store nutrients in wastewater, such as carbon (C), nitrogen (N), and phosphorus (P). It makes the study of the mechanisms underlying the uptake and storage of nutrients in microalgae of great interest. This review specifically aims to summarize C, N, and P metabolisms in microalgae for a better understanding of the microalgae-based wastewater treatment from the nutrient uptake pathway, and examine the key physiological factors or the operating conditions related to nutrient metabolisms that may affect the treatment efficiency. At last, I discuss the potential approaches to enhance the overall treatment performance by adjusting the critical parameters for C, N, and P metabolisms.
Collapse
Affiliation(s)
- Yanyan Su
- Carlsberg Research Laboratory, Bjerregaardsvej 5, 2500 Valby, Denmark.
| |
Collapse
|
2
|
Calatrava V, Chamizo-Ampudia A, Sanz-Luque E, Ocaña-Calahorro F, Llamas A, Fernandez E, Galvan A. How Chlamydomonas handles nitrate and the nitric oxide cycle. JOURNAL OF EXPERIMENTAL BOTANY 2017; 68:2593-2602. [PMID: 28201747 DOI: 10.1093/jxb/erw507] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
The green alga Chlamydomonas is a valuable model system capable of assimilating different forms of nitrogen (N). Nitrate (NO3-) has a relevant role in plant-like organisms, first as a nitrogen source for growth and second as a signalling molecule. Several modules are necessary for Chlamydomonas to handle nitrate, including transporters, nitrate reductase (NR), nitrite reductase (NiR), GS/GOGAT enzymes for ammonium assimilation, and regulatory protein(s). Transporters provide a first step for influx/efflux, homeostasis, and sensing of nitrate; and NIT2 is the key transcription factor (RWP-RK) for mediating the nitrate-dependent activation of a number of genes. Here, we review how NR participates in the cycle NO3- →NO2- →NO →NO3-. NR uses the partner protein amidoxime-reducing component/nitric oxide-forming nitrite reductase (ARC/NOFNiR) for the conversion of nitrite (NO2-) into nitric oxide (NO). It also uses the truncated haemoglobin THB1 in the conversion of nitric oxide to nitrate. Nitric oxide is a negative signal for nitrate assimilation; it inhibits the activity and expression of high-affinity nitrate/nitrite transporters and NR. During this cycle, the positive signal of nitrate is transformed into the negative signal of nitric oxide, which can then be converted back into nitrate. Thus, NR is back in the spotlight as a strategic regulator of the nitric oxide cycle and the nitrate assimilation pathway.
Collapse
Affiliation(s)
- Victoria Calatrava
- Departamento de Bioquímica y Biología Molecular, Campus de Rabanales y Campus Internacional de Excelencia Agroalimentario (CeiA3), Edif. Severo Ochoa, Universidad de Córdoba, Spain
| | - Alejandro Chamizo-Ampudia
- Departamento de Bioquímica y Biología Molecular, Campus de Rabanales y Campus Internacional de Excelencia Agroalimentario (CeiA3), Edif. Severo Ochoa, Universidad de Córdoba, Spain
| | - Emanuel Sanz-Luque
- Departamento de Bioquímica y Biología Molecular, Campus de Rabanales y Campus Internacional de Excelencia Agroalimentario (CeiA3), Edif. Severo Ochoa, Universidad de Córdoba, Spain
| | - Francisco Ocaña-Calahorro
- Departamento de Bioquímica y Biología Molecular, Campus de Rabanales y Campus Internacional de Excelencia Agroalimentario (CeiA3), Edif. Severo Ochoa, Universidad de Córdoba, Spain
| | - Angel Llamas
- Departamento de Bioquímica y Biología Molecular, Campus de Rabanales y Campus Internacional de Excelencia Agroalimentario (CeiA3), Edif. Severo Ochoa, Universidad de Córdoba, Spain
| | - Emilio Fernandez
- Departamento de Bioquímica y Biología Molecular, Campus de Rabanales y Campus Internacional de Excelencia Agroalimentario (CeiA3), Edif. Severo Ochoa, Universidad de Córdoba, Spain
| | - Aurora Galvan
- Departamento de Bioquímica y Biología Molecular, Campus de Rabanales y Campus Internacional de Excelencia Agroalimentario (CeiA3), Edif. Severo Ochoa, Universidad de Córdoba, Spain
| |
Collapse
|
3
|
NRT2.4 and NRT2.5 Are Two Half-Size Transporters from the Chlamydomonas NRT2 Family. AGRONOMY-BASEL 2016. [DOI: 10.3390/agronomy6010020] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
|
4
|
Charrier A, Bérard JB, Bougaran G, Carrier G, Lukomska E, Schreiber N, Fournier F, Charrier AF, Rouxel C, Garnier M, Cadoret JP, Saint-Jean B. High-affinity nitrate/nitrite transporter genes (Nrt2) in Tisochrysis lutea: identification and expression analyses reveal some interesting specificities of Haptophyta microalgae. PHYSIOLOGIA PLANTARUM 2015; 154:572-90. [PMID: 25640753 DOI: 10.1111/ppl.12330] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Revised: 01/27/2015] [Accepted: 01/27/2015] [Indexed: 05/26/2023]
Abstract
Microalgae have a diversity of industrial applications such as feed, food ingredients, depuration processes and energy. However, microalgal production costs could be substantially improved by controlling nutrient intake. Accordingly, a better understanding of microalgal nitrogen metabolism is essential. Using in silico analysis from transcriptomic data concerning the microalgae Tisochrysis lutea, four genes encoding putative high-affinity nitrate/nitrite transporters (TlNrt2) were identified. Unlike most of the land plants and microalgae, cloning of genomic sequences and their alignment with complementary DNA (cDNA) sequences did not reveal the presence of introns in all TlNrt2 genes. The deduced TlNRT2 protein sequences showed similarities to NRT2 proteins of other phyla such as land plants and green algae. However, some interesting specificities only known among Haptophyta were also revealed, especially an additional sequence of 100 amino acids forming an atypical extracellular loop located between transmembrane domains 9 and 10 and the function of which remains to be elucidated. Analyses of individual TlNrt2 gene expression with different nitrogen sources and concentrations were performed. TlNrt2.1 and TlNrt2.3 were strongly induced by low NO3 (-) concentration and repressed by NH4 (+) substrate and were classified as inducible genes. TlNrt2.2 was characterized by a constitutive pattern whatever the substrate. Finally, TlNrt2.4 displayed an atypical response that was not reported earlier in literature. Interestingly, expression of TlNrt2.4 was rather related to internal nitrogen quota level than external nitrogen concentration. This first study on nitrogen metabolism of T. lutea opens avenues for future investigations on the function of these genes and their implication for industrial applications.
Collapse
Affiliation(s)
- Aurélie Charrier
- Physiology and Biotechnology of Algae Laboratory, IFREMER, Nantes, 44311, France
| | - Jean-Baptiste Bérard
- Physiology and Biotechnology of Algae Laboratory, IFREMER, Nantes, 44311, France
| | - Gaël Bougaran
- Physiology and Biotechnology of Algae Laboratory, IFREMER, Nantes, 44311, France
| | - Grégory Carrier
- Physiology and Biotechnology of Algae Laboratory, IFREMER, Nantes, 44311, France
| | - Ewa Lukomska
- Physiology and Biotechnology of Algae Laboratory, IFREMER, Nantes, 44311, France
| | - Nathalie Schreiber
- Physiology and Biotechnology of Algae Laboratory, IFREMER, Nantes, 44311, France
| | - Flora Fournier
- Physiology and Biotechnology of Algae Laboratory, IFREMER, Nantes, 44311, France
| | - Aurélie F Charrier
- Physiology and Biotechnology of Algae Laboratory, IFREMER, Nantes, 44311, France
| | - Catherine Rouxel
- Physiology and Biotechnology of Algae Laboratory, IFREMER, Nantes, 44311, France
| | - Matthieu Garnier
- Physiology and Biotechnology of Algae Laboratory, IFREMER, Nantes, 44311, France
| | - Jean-Paul Cadoret
- Physiology and Biotechnology of Algae Laboratory, IFREMER, Nantes, 44311, France
| | - Bruno Saint-Jean
- Physiology and Biotechnology of Algae Laboratory, IFREMER, Nantes, 44311, France
| |
Collapse
|
5
|
Kotur Z, Siddiqi YM, Glass ADM. Characterization of nitrite uptake in Arabidopsis thaliana: evidence for a nitrite-specific transporter. THE NEW PHYTOLOGIST 2013; 200:201-210. [PMID: 23763619 DOI: 10.1111/nph.12358] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2013] [Accepted: 05/08/2013] [Indexed: 05/16/2023]
Abstract
Nitrite-specific plasma membrane transporters have been described in bacteria, algae and fungi, but there is no evidence of a nitrite-specific plasma membrane transporter in higher plants. We have used 13NO2(-) to characterize nitrite influx into roots of Arabidopsis thaliana. Hydroponically grown Arabidopsis mutants, defective in high-affinity nitrate transport, were used to distinguish between nitrate and nitrite uptake by means of the short-lived tracers 13NO2(-) and 13NO3(-). This approach allowed us to characterize a nitrite-specific transporter. The Atnar2.1-2 mutant, lacking a functional high-affinity nitrate transport system, is capable of nitrite influx that is constitutive and thermodynamically active. The corresponding fluxes conform to a rectangular hyperbola, exhibiting saturation at concentrations above 200 μM (Km = 185 μM and Vmax = 1.89 μmol g(-1) FW h(-1)). Nitrite influx via the putative nitrite transporter is not subject to competitive inhibition by nitrate but is downregulated after 6 h exposure to ammonium. These results signify the existence of a nitrite-specific transporter in Arabidopsis. This transporter enables Atnar2.1-2 mutants, which are incapable of sustained growth on low nitrate, to maintain significant growth on low nitrite. In wild-type plants, this nitrite flux may increase nitrogen acquisition and also participate in the induction of genes specifically induced by nitrite.
Collapse
Affiliation(s)
- Zorica Kotur
- Department of Botany, University of British Columbia, 6270 University Boulevard, Vancouver, British Columbia, V6T1Z4, Canada
| | - Yaeesh M Siddiqi
- Department of Botany, University of British Columbia, 6270 University Boulevard, Vancouver, British Columbia, V6T1Z4, Canada
| | - Anthony D M Glass
- Department of Botany, University of British Columbia, 6270 University Boulevard, Vancouver, British Columbia, V6T1Z4, Canada
| |
Collapse
|
6
|
Scherholz ML, Curtis WR. Achieving pH control in microalgal cultures through fed-batch addition of stoichiometrically-balanced growth media. BMC Biotechnol 2013; 13:39. [PMID: 23651806 PMCID: PMC3751429 DOI: 10.1186/1472-6750-13-39] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2012] [Accepted: 02/25/2013] [Indexed: 11/10/2022] Open
Abstract
Background Lack of accounting for proton uptake and secretion has confounded interpretation of the stoichiometry of photosynthetic growth of algae. This is also problematic for achieving growth of microalgae to high cell concentrations which is necessary to improve productivity and the economic feasibility of commercial-scale chemical production systems. Since microalgae are capable of consuming both nitrate and ammonium, this represents an opportunity to balance culture pH based on a nitrogen feeding strategy that does not utilize gas-phase CO2 buffering. Stoichiometry suggests that approximately 36 weight%N-NH4+ (balance nitrogen as NO3-) would minimize the proton imbalance and permit high-density photoautotrophic growth as it does in higher plant tissue culture. However, algal media almost exclusively utilize nitrate, and ammonium is often viewed as ‘toxic’ to algae. Results The microalgae Chlorella vulgaris and Chlamydomonas reinhardtii exclusively utilize ammonium when both ammonium and nitrate are provided during growth on excess CO2. The resulting proton imbalance from preferential ammonium utilization causes the pH to drop too low to sustain further growth when ammonium was only 9% of the total nitrogen (0.027 gN-NH4+/L). However, providing smaller amounts of ammonium sequentially in the presence of nitrate maintained the pH of a Chlorella vulgaris culture for improved growth on 0.3 gN/L to 5 gDW/L under 5% CO2 gas-phase supplementation. Bioreactor pH dynamics are shown to be predictable based on simple nitrogen assimilation as long as there is sufficient CO2 availability. Conclusions This work provides both a media formulation and a feeding strategy with a focus on nitrogen metabolism and regulation to support high-density algal culture without buffering. The instability in culture pH that is observed in microalgal cultures in the absence of buffers can be overcome through alternating utilization of ammonium and nitrate. Despite the highly regulated array of nitrogen transporters, providing a nitrogen source with a balanced degree of reduction minimizes pH fluctuations. Understanding and accommodating the behavior of nitrogen utilization in microalgae is key to avoiding ‘culture crash’ and reliance on gas phase CO2 buffering, which becomes both ineffective and cost-prohibitive for commercial-scale algal culture.
Collapse
Affiliation(s)
- Megerle L Scherholz
- Department of Chemical Engineering, Pennsylvania State University, University Park, PA 16802, USA
| | | |
Collapse
|
7
|
Fukuzawa H, Ogawa T, Kaplan A. The Uptake of CO2 by Cyanobacteria and Microalgae. PHOTOSYNTHESIS 2012. [DOI: 10.1007/978-94-007-1579-0_25] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
|
8
|
Affiliation(s)
- Emilio Fernandez
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias, Universidad de Córdoba, Campus de Rabanales, Edif. Severo Ochoa, 14071-Córdoba, Spain.
| | | |
Collapse
|
9
|
Camargo A, Llamas A, Schnell RA, Higuera JJ, González-Ballester D, Lefebvre PA, Fernández E, Galván A. Nitrate signaling by the regulatory gene NIT2 in Chlamydomonas. THE PLANT CELL 2007; 19:3491-503. [PMID: 18024571 PMCID: PMC2174885 DOI: 10.1105/tpc.106.045922] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2006] [Revised: 10/19/2007] [Accepted: 11/01/2007] [Indexed: 05/18/2023]
Abstract
Positive signaling by nitrate in its assimilation pathway has been studied in Chlamydomonas reinhardtii. Among >34,000 lines generated by plasmid insertion, 10 mutants were unable to activate nitrate reductase (NIA1) gene expression and had a Nit(-) (no growth in nitrate) phenotype. Each of these 10 lines was mutated in the nitrate assimilation-specific regulatory gene NIT2. The complete NIT2 cDNA sequence was obtained, and its deduced amino acid sequence revealed GAF, Gln-rich, Leu zipper, and RWP-RK domains typical of transcription factors and transcriptional coactivators associated with signaling pathways. The predicted Nit2 protein sequence is structurally related to the Nin (for nodule inception) proteins from plants but not to NirA/Nit4/Yna proteins from fungi and yeast. NIT2 expression is negatively regulated by ammonium and is optimal in N-free medium with no need for the presence of nitrate. However, intracellular nitrate is required to allow Nit2 to activate the NIA1 promoter activity. Nit2 protein was expressed in Escherichia coli and shown to bind to specific sequences at the NIA1 gene promoter. Our data indicate that NIT2 is a central regulatory gene required for nitrate signaling on the Chlamydomonas NIA1 gene promoter and that intracellular nitrate is needed for NIT2 function and to modulate NIA1 transcript levels.
Collapse
Affiliation(s)
- Antonio Camargo
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias, Universidad de Córdoba, Campus de Rabanales, 14071 Córdoba, Spain
| | | | | | | | | | | | | | | |
Collapse
|
10
|
Eriksen NT, Riisgård FK, Gunther WS, Lønsmann Iversen JJ. On-line estimation of O(2) production, CO(2) uptake, and growth kinetics of microalgal cultures in a gas-tight photobioreactor. JOURNAL OF APPLIED PHYCOLOGY 2007; 19:161-174. [PMID: 19396354 PMCID: PMC2668643 DOI: 10.1007/s10811-006-9122-y] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2006] [Accepted: 08/06/2006] [Indexed: 05/07/2023]
Abstract
Growth of the green algae Chlamydomonas reinhardtii and Chlorella sp. in batch cultures was investigated in a novel gas-tight photobioreactor, in which CO(2), H(2), and N(2) were titrated into the gas phase to control medium pH, dissolved oxygen partial pressure, and headspace pressure, respectively. The exit gas from the reactor was circulated through a loop of tubing and re-introduced into the culture. CO(2) uptake was estimated from the addition of CO(2) as acidic titrant and O(2) evolution was estimated from titration by H(2), which was used to reduce O(2) over a Pd catalyst. The photosynthetic quotient, PQ, was estimated as the ratio between O(2) evolution and CO(2) up-take rates. NH(4) (+), NO(2) (-), or NO(3) (-) was the final cell density limiting nutrient. Cultures of both algae were, in general, characterised by a nitrogen sufficient growth phase followed by a nitrogen depleted phase in which starch was the major product. The estimated PQ values were dependent on the level of oxidation of the nitrogen source. The PQ was 1 with NH(4) (+) as the nitrogen source and 1.3 when NO(3) (-) was the nitrogen source. In cultures grown on all nitrogen sources, the PQ value approached 1 when the nitrogen source was depleted and starch synthesis became dominant, to further increase towards 1.3 over a period of 3-4 days. This latter increase in PQ, which was indicative of production of reduced compounds like lipids, correlated with a simultaneous increase in the degree of reduction of the biomass. When using the titrations of CO(2) and H(2) into the reactor headspace to estimate the up-take of CO(2), the production of O(2), and the PQ, the rate of biomass production could be followed, the stoichiometrical composition of the produced algal biomass could be estimated, and different growth phases could be identified.
Collapse
Affiliation(s)
- Niels Thomas Eriksen
- Department of Biotechnology, Chemistry and Environmental Engineering, Aalborg University, Sohngaardsholmsvej 49, 9000 Aalborg, Denmark
| | - Frederik Kier Riisgård
- Department of Biotechnology, Chemistry and Environmental Engineering, Aalborg University, Sohngaardsholmsvej 49, 9000 Aalborg, Denmark
| | - William Stuart Gunther
- Department of Biotechnology, Chemistry and Environmental Engineering, Aalborg University, Sohngaardsholmsvej 49, 9000 Aalborg, Denmark
| | - Jens Jørgen Lønsmann Iversen
- Institute of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark
| |
Collapse
|
11
|
Tsujimoto R, Yamazaki H, Maeda SI, Omata T. Distinct roles of nitrate and nitrite in regulation of expression of the nitrate transport genes in the moss Physcomitrella patens. PLANT & CELL PHYSIOLOGY 2007; 48:484-97. [PMID: 17289796 DOI: 10.1093/pcp/pcm019] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Five NRT2 genes and three Nar2 genes, encoding putative high-affinity nitrate transporters, and the respective cDNAs were identified and characterized in Physcomitrella patens. The deduced moss NRT2 and NAR2 proteins were more similar to the corresponding proteins of higher plants than to those of the green alga Chlamydomonas reinhardtii. Expression of all the genes was inhibited by ammonium added to the medium. The regulation by ammonium was abolished by an inhibitor of glutamine synthetase, but the effect of this inhibitor was counteracted by an inhibitor of glutamate synthase. Negative correlation was observed between the glutamine content of protonemata and the transcript levels of PpNRT2 and PpNar2. These results indicated that glutamine is the signal for repression of the genes. All the genes except PpNRT2;5 showed transient expression stimulated by nitrate but not by nitrite, peaking at 2-4 h after the medium was deprived of ammonium. When the glutamine synthetase inhibitor was used to inhibit assimilation of the ammonium generated intracellularly from nitrate or nitrite, the second phase of activation of genes became manifest at approximately 8 h after the medium was deprived of ammonium. Surprisingly, both nitrate and nitrite stimulated gene expression at this stage. PpNRT2;5 was distinct from the other genes in that its expression is sharply induced by nitrite, is strictly dependent on nitrite or nitrate, and is much less susceptible to the feedback regulation, retaining a constant level in nitrate-containing medium. These results indicated that P. patens has multiple mechanisms for sensing nitrate and nitrite.
Collapse
Affiliation(s)
- Ryoma Tsujimoto
- Laboratory of Molecular Plant Physiology, Graduate School of Bioagricultural Sciences, Nagoya University, Chikusa, Nagoya, 464-8601, Japan
| | | | | | | |
Collapse
|
12
|
Sakakibara H, Takei K, Hirose N. Interactions between nitrogen and cytokinin in the regulation of metabolism and development. TRENDS IN PLANT SCIENCE 2006; 11:440-8. [PMID: 16899391 DOI: 10.1016/j.tplants.2006.07.004] [Citation(s) in RCA: 237] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2006] [Revised: 06/15/2006] [Accepted: 07/25/2006] [Indexed: 05/11/2023]
Abstract
Inorganic nitrogen is a substrate for nitrogen assimilation and also functions as a signal triggering widespread changes in gene expression that modulate metabolism and development. To integrate the actions of the nitrogen signal at the whole plant level, plants use multiple signaling routes that communicate internal and external nitrogen status. One route depends on nitrate itself and one uses cytokinin as a messenger. Recent genome-wide research has shown that the nitrate-specific signal regulates a wide variety of metabolic processes including nitrogen and carbon metabolism, and cytokinin biosynthesis. Cytokinin-mediated signaling is related to the control of development, protein synthesis and acquisition of macronutrients. The coordination and interaction of both regulatory pathways is important for normal plant growth under variable nitrogen supply conditions.
Collapse
Affiliation(s)
- Hitoshi Sakakibara
- RIKEN Plant Science Center, 1-7-22 Suehiro, Tsurumi, Yokohama 230-0045, Japan.
| | | | | |
Collapse
|
13
|
Nakamura Y, Kanakagiri S, Van K, He W, Spalding MH. Disruption of the glycolate dehydrogenase gene in the high-CO2-requiring mutant HCR89 ofChlamydomonas reinhardtii. ACTA ACUST UNITED AC 2005. [DOI: 10.1139/b05-067] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
One of the most notable contrasts between the photorespiratory pathway of higher plants and that of many of the green algae including Chlamydomonas reinhardtii lies in the enzymes that serve for oxidation of glycolate to glyoxylate. The gene disrupted by insertional mutagenesis in a high-CO2-requiring mutant, HCR89, of C. reinhardtii was determined to encode glycolate dehydrogenase (EC 1.1.99.14), which serves as the counterpart of glycolate oxidase (EC 1.1.3.15) in classical higher plant photorespiration. Neither glycolate nor D-lactate oxidation from the membrane fraction of HCR89 was detected. Excretion of over-accumulated glycolate into media due to the absence of glycolate dehydrogenase activity was observed for HCR89 under both high- and low-CO2conditions. Chlamydomonas glycolate dehydrogenase, CrGDH, with a molecular mass of 118 851 Da, comprises a relatively hydrophobic N-terminal region, a FAD-containing domain homologous to the D subunit of the glycolate oxidase complex from Escherischia coli, and an ironsulfur cluster containing domain homologous to the C subunit of anaerobic glycerol-3-phosphate dehydrogenase complex from Escherichia coli. The second Cys residue in the second ironsulfur cluster motif of CrGDH is replaced by Asp, as CxxDxxCxxxCP, indicating the second ironsulfur cluster coordinates most likely 3Fe4S instead of 4Fe4S. The membrane association of the glycolate dehydrogenase activity agrees with three predicted transmembrane regions on the ironsulfur domain.Key words: algae, Chlamydomonas, CO2, glycolate, lactate, mitochondria, photorespiration, photosynthesis.
Collapse
|
14
|
González-Ballester D, de Montaigu A, Higuera JJ, Galván A, Fernández E. Functional genomics of the regulation of the nitrate assimilation pathway in Chlamydomonas. PLANT PHYSIOLOGY 2005; 137:522-33. [PMID: 15665251 PMCID: PMC1065353 DOI: 10.1104/pp.104.050914] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2004] [Revised: 10/13/2004] [Accepted: 10/14/2004] [Indexed: 05/18/2023]
Abstract
The existence of mutants at specific steps in a pathway is a valuable tool of functional genomics in an organism. Heterologous integration occurring during transformation with a selectable marker in Chlamydomonas (Chlamydomonas reinhardtii) has been used to generate an ordered mutant library. A strain, having a chimeric construct (pNia1::arylsulfatase gene) as a sensor of the Nia1 gene promoter activity, was transformed with a plasmid bearing the paramomycin resistance AphVIII gene to generate insertional mutants defective at regulatory steps of the nitrate assimilation pathway. Twenty-two thousand transformants were obtained and maintained in pools of 96 for further use. The mutant library was screened for the following phenotypes: insensitivity to the negative signal of ammonium, insensitivity to the positive signal of nitrate, overexpression in nitrate, and inability to use nitrate. Analyses of mutants showed that (1) the number or integrated copies of the gene marker is close to 1; (2) the probability of cloning the DNA region at the marker insertion site is high (76%); (3) insertions occur randomly; and (4) integrations at different positions and orientations of the same genomic region appeared in at least three cases. Some of the mutants analyzed were found to be affected at putative new genes related to regulatory functions, such as guanylate cyclase, protein kinase, peptidyl-prolyl isomerase, or DNA binding. The Chlamydomonas mutant library constructed would also be valuable to identify any other gene with a screenable phenotype.
Collapse
Affiliation(s)
- David González-Ballester
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias, Universidad de Cordoba, Campus de Rabanales, 14071 Cordoba, Spain
| | | | | | | | | |
Collapse
|
15
|
Navarro MT, Mariscal V, Macías MI, Fernández E, Galván A. Chlamydomonas reinhardtii strains expressing nitrate reductase under control of the cabII-1 promoter: isolation of chlorate resistant mutants and identification of new loci for nitrate assimilation. PHOTOSYNTHESIS RESEARCH 2005; 83:151-61. [PMID: 16143849 DOI: 10.1007/s11120-004-9297-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2004] [Accepted: 04/29/2004] [Indexed: 05/04/2023]
Abstract
The Chlamydomonas reinhardtii strain Tx11-8 is a transgenic alga that bears the nitrate reductase gene (Nia1) under control of the CabII-1 gene promoter (CabII-1-Nia1). Approximately nine copies of the chimeric CabII-1-Nia1 gene were found to be integrated in this strain and to confer a phenotype of chlorate sensitivity in the presence of ammonium. We have used this strain for the isolation of spontaneous chlorate resistant mutants in the presence of ammonium that were found to be defective at loci involved in MoCo metabolism and light-dependent growth in nitrate media. Of a total of 45 mutant strains analyzed first, 44 were affected in the MoCo activity (16 Nit(-), unable to grow in nitrate, and 28 Nit(+), able to grow in nitrate). All the Nit(-) strains lacked MoCo activity. Diploid complementation of Nit(-), MoCo(-) strains with C. reinhardtii MoCo mutants and genetic analysis indicated that some strains were defective at known loci for MoCo biosynthesis, while three strains were defective at two new loci, hereafter named Nit10 and Nit11. The other 28 Nit(+) strains showed almost undetectable MoCo activity or activity was below 20% of the parental strain. Second, only one strain (named 23c(+)) showed MoCo and NR activities comparable to those in the parental strain. Strain 23c(+) seems to be affected in a locus, Nit12, required for growth in nitrate under continuous light. It is proposed that this locus is required for nitrate/chlorate transport activity. In this work, mechanisms of chlorate toxicity are reviewed in the light of our results.
Collapse
Affiliation(s)
- María Teresa Navarro
- Departamento de Ciencias Ambientales, Area de Fisiología Vegetal, Facultad de Ciencias Experimentales, Universidad Pablo de Olavide, Carretera de Utrera, Seville 41013, Spain
| | | | | | | | | |
Collapse
|
16
|
González-Ballester D, Camargo A, Fernández E. Ammonium transporter genes in Chlamydomonas: the nitrate-specific regulatory gene Nit2 is involved in Amt1;1 expression. PLANT MOLECULAR BIOLOGY 2004; 56:863-78. [PMID: 15821986 DOI: 10.1007/s11103-004-5292-7] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2004] [Accepted: 10/21/2004] [Indexed: 05/04/2023]
Abstract
Ammonium transport is a key process in nitrogen metabolism. In the green alga Chlamydomonas, we have characterized molecularly the largest family of ammonium transporters (AMT1) so far described consisting of eight members. CrAmt1 genes have an interesting transcript structure with some very small exons. Differential expression patterns were found for each CrAmt1 gene in response to the nitrogen source by using Real Time PCR. These expression patterns were similar under high and low CO2 atmosphere. CrAmt1;1 expression was characterized in detail. It was repressed in both ammonium and nitrate medium, and strongly expressed in nitrogen-free media. Treatment with a Glutamine synthetase inhibitor released partially repression in ammonium and nitrate suggesting that ammonium and its derivatives participate in the observed repressing effects. By studying CrAmt1;1 expression in mutants deficient at different steps of the nitrate assimilation pathway, it has been shown that nitrate has a double negative effect on this gene expression; one related to its reduction to ammonium, and a second one by itself. This second effect of nitrate was dependent on the functionality of the regulatory gene Nit2, specific for nitrate assimilation. Thus, NIT2 would have a dual role on gene expression: the well-known positive one on nitrate assimilation and a novel negative one on Amt1;1 regulation.
Collapse
Affiliation(s)
- David González-Ballester
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias, Edificio Severo Ochoa Planta baja, Universidad de Córdoba, Campus de Rabanales, Spain
| | | | | |
Collapse
|
17
|
Baurain D, Dinant M, Coosemans N, Matagne RF. Regulation of the alternative oxidase Aox1 gene in Chlamydomonas reinhardtii. Role of the nitrogen source on the expression of a reporter gene under the control of the Aox1 promoter. PLANT PHYSIOLOGY 2003; 131:1418-30. [PMID: 12644691 PMCID: PMC166901 DOI: 10.1104/pp.013409] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2002] [Revised: 11/03/2002] [Accepted: 12/10/2002] [Indexed: 05/21/2023]
Abstract
In higher plants, various developmental and environmental conditions enhance expression of the alternative oxidase (AOX), whereas its induction in fungi is mainly dependent on cytochrome pathway restriction and triggering by reactive oxygen species. The AOX of the unicellular green alga Chlamydomonas reinhardtii is encoded by two different genes, the Aox1 gene being much more transcribed than Aox2. To analyze the transcriptional regulation of Aox1, we have fused its 1.4-kb promoter region to the promoterless arylsulfatase (Ars) reporter gene and measured ARS enzyme activities in transformants carrying the chimeric construct. We show that the Aox1 promoter is generally unresponsive to a number of known AOX inducers, including stress agents, respiratory inhibitors, and metabolites, possibly because the AOX activity is constitutively high in the alga. In contrast, the Aox1 expression is strongly dependent on the nitrogen source, being down-regulated by ammonium and stimulated by nitrate. Inactivation of nitrate reductase leads to a further increase of expression. The stimulation by nitrate also occurs at the AOX protein and respiratory levels. A deletion analysis of the Aox1 promoter region demonstrates that a short upstream segment (-253 to +59 with respect to the transcription start site) is sufficient to ensure gene expression and regulation, but that distal elements are required for full gene expression. The observed pattern of AOX regulation points to the possible interaction between chloroplast and mitochondria in relation to a potential increase of photogenerated ATP when nitrate is used as a nitrogen source.
Collapse
Affiliation(s)
- Denis Baurain
- Genetics of Microorganisms, Department of Life Sciences, B22, University of Liège, Sart Tilman, B-4000 Liège, Belgium
| | | | | | | |
Collapse
|
18
|
Abstract
Nitrate assimilation has received much attention in filamentous fungi and plants but not so much in yeasts. Recently the availability of classical genetic and molecular biology tools for the yeast Hansenula polymorpha has allowed the advance of the study of this metabolic pathway in yeasts. The genes YNT1, YNR1 and YNI1, encoding respectively nitrate transport, nitrate reductase and nitrite reductase, have been cloned, as well as two other genes encoding transcriptional regulatory factors. All these genes lie closely together in a cluster. Transcriptional regulation is the main regulatory mechanism that controls the levels of the enzymes involved in nitrate metabolism although other mechanisms may also be operative. The process involved in the sensing and signalling of the presence of nitrate in the medium is not well understood. In this article the current state of the studies of nitrate assimilation in yeasts as well as possible venues for future research are reviewed.
Collapse
Affiliation(s)
- José M Siverio
- Departamento de Bioquímica y Biología Molecular, Grupo del Metabolismo del Nitrógeno, Universidad de La Laguna, E-38206 La Laguna, Tenerife, Spain.
| |
Collapse
|
19
|
Llamas A, Igeño MI, Galván A, Fernández E. Nitrate signalling on the nitrate reductase gene promoter depends directly on the activity of the nitrate transport systems in Chlamydomonas. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2002; 30:261-71. [PMID: 12000675 DOI: 10.1046/j.1365-313x.2002.01281.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Nitrate signalling on the nitrate reductase (Nia1) gene promoter from Chlamydomonas reinhardtii has been studied by using a construct of the Nia1 promoter transcriptionally fused to the Chlamydomonas arylsulphatase gene as a reporter in strains bearing different sets of nitrate/nitrite transport genes. The high-affinity nitrate transport (HANT) system I is required for efficient signalling by nitrate, even at submicromolar concentrations of the anion. In addition, the autogenous regulation of nitrate reductase has been found to depend on the presence of system I. The low-affinity nitrate transport system III promoted signalling optimally on the promoter at millimolar nitrate concentrations. The HANT system IV, which is insensitive to ammonium and active at low CO2, allowed nitrate signalling at micromolar concentrations even in the presence of ammonium, suggesting that the balance of these two effectors controls Nia1 transcription. Our data indicate that nitrate signalling on the Nia1 gene promoter occurs intracellularly and depends on the activity of nitrate transporters.
Collapse
Affiliation(s)
- Angel Llamas
- Departamento de Bioquímica y Biología Molecular, Campus de Rabanales, Edificio Severo Ochoa, Universidad de Córdoba, 14071-Córdoba, Spain
| | | | | | | |
Collapse
|
20
|
Soluble and Plasma Membrane-bound Enzymes Involved in Nitrate and Nitrite Metabolism. ADVANCES IN PHOTOSYNTHESIS AND RESPIRATION 2002. [DOI: 10.1007/0-306-48138-3_4] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
|
21
|
Williams LE, Miller AJ. TRANSPORTERS RESPONSIBLE FOR THE UPTAKE AND PARTITIONING OF NITROGENOUS SOLUTES. ANNUAL REVIEW OF PLANT PHYSIOLOGY AND PLANT MOLECULAR BIOLOGY 2001; 52:659-688. [PMID: 11337412 DOI: 10.1146/annurev.arplant.52.1.659] [Citation(s) in RCA: 143] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The acquisition and allocation of nitrogenous compounds are essential processes in plant growth and development. The huge economic and environmental costs resulting from the application of nitrogen fertilizers make this topic very important. A diverse array of transporters varying in their expression pattern and also in their affinity, specificity, and capacity for nitrogenous compounds has been identified. Now the future challenge is to define their individual contribution to nitrogen nutrition and signalling processes. Here we have reviewed recent advances in the identification and molecular characterization of these transporters, concentrating on mechanisms existing at the plasma membrane. The review focuses on nitrate, ammonium, and amino acid transporter familes, but we also briefly describe what is known at the molecular level about peptide transporters and a recently identified family implicated in the transport of purines and their derivatives.
Collapse
Affiliation(s)
- LE Williams
- School of Biological Sciences, University of Southampton, Bassett Crescent East, Southampton, SO16, 7PX, United Kingdom; e-mail: , Biochemistry and Physiology Department, IARC-Rothamsted, Harpenden, Herts AL5 2JQ, United Kingdom; e-mail:
| | | |
Collapse
|
22
|
Grossman A, Takahashi H. MACRONUTRIENT UTILIZATION BY PHOTOSYNTHETIC EUKARYOTES AND THE FABRIC OF INTERACTIONS. ANNUAL REVIEW OF PLANT PHYSIOLOGY AND PLANT MOLECULAR BIOLOGY 2001; 52:163-210. [PMID: 11337396 DOI: 10.1146/annurev.arplant.52.1.163] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Organisms acclimate to a continually fluctuating nutrient environment. Acclimation involves responses specific for the limiting nutrient as well as responses that are more general and occur when an organism experiences different stress conditions. Specific responses enable organisms to efficiently scavenge the limiting nutrient and may involve the induction of high-affinity transport systems and the synthesis of hydrolytic enzymes that facilitate the release of the nutrient from extracellular organic molecules or from internal reserves. General responses include changes in cell division rates and global alterations in metabolic activities. In photosynthetic organisms there must be precise regulation of photosynthetic activity since when severe nutrient limitation prevents continued cell growth, excitation of photosynthetic pigments could result in the formation of reactive oxygen species, which can severely damage structural and functional features of the cell. This review focuses on ways that photosynthetic eukaryotes assimilate the macronutrients nitrogen, sulfur, and phosphorus, and the mechanisms that govern assimilatory activities. Also discussed are molecular responses to macronutrient limitation and the elicitation of those responses through integration of environmental and cellular cues.
Collapse
Affiliation(s)
- Arthur Grossman
- Department of Plant Biology, The Carnegie Institution of Washington 260 Panama Street, Stanford, California 94305; e-mail: , RIKEN Plant Science Center, 2-l Hirosawa, Wako, Saitama, 351-0198, Japan; e-mail:
| | | |
Collapse
|
23
|
Abstract
To cope with low nutrient availability in nature, organisms have evolved inducible systems that enable them to scavenge and efficiently utilize the limiting nutrient. Furthermore, organisms must have the capacity to adjust their rate of metabolism and make specific alterations in metabolic pathways that favor survival when the potential for cell growth and division is reduced. In this article I will focus on the acclimation of Chlamydomonas reinhardtii, a unicellular, eukaryotic green alga to conditions of nitrogen, sulfur and phosphorus deprivation. This organism has a distinguished history as a model for classical genetic analyses, but it has recently been developed for exploitation using an array of molecular and genomic tools. The application of these tools to the analyses of nutrient limitation responses (and other biological processes) is revealing mechanisms that enable Chlamydomonas to survive harsh environmental conditions and establishing relationships between the responses of this morphologically simple, photosynthetic eukaryote and those of both nonphotosynthetic organisms and vascular plants.
Collapse
|
24
|
Forde BG. Nitrate transporters in plants: structure, function and regulation. BIOCHIMICA ET BIOPHYSICA ACTA 2000; 1465:219-35. [PMID: 10748256 DOI: 10.1016/s0005-2736(00)00140-1] [Citation(s) in RCA: 262] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Physiological studies have established that plants acquire their NO(-3) from the soil through the combined activities of a set of high- and low-affinity NO(-3) transport systems, with the influx of NO(-3) being driven by the H(+) gradient across the plasma membrane. Some of these NO(-3) transport systems are constitutively expressed, while others are NO(-3)-inducible and subject to negative feedback regulation by the products of NO(-3) assimilation. Here we review recent progress in the characterisation of the two families of NO(-3) transporters that have so far been identified in plants, their structure and their regulation, and consider the evidence for their roles in NO(-3) acquisition. We also discuss what is currently known about the genetic basis of NO(-3) induction and feedback repression of the NO(-3) transport and assimilatory pathway in higher plants.
Collapse
Affiliation(s)
- B G Forde
- Biochemistry and Physiology Department, IACR-Rothamsted, Harpenden, UK.
| |
Collapse
|
25
|
Zhou JJ, Fernández E, Galván A, Miller AJ. A high affinity nitrate transport system from Chlamydomonas requires two gene products. FEBS Lett 2000; 466:225-7. [PMID: 10682832 DOI: 10.1016/s0014-5793(00)01085-1] [Citation(s) in RCA: 91] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
A nitrate-regulated cluster of genes involved in nitrate transport and assimilation has been identified in Chlamydomonas reinhardtii. Mutant strains of the alga, which are defective in some aspect of transport and assimilation have been used to assign functions to these genes. This analysis has suggested that two gene products are necessary to obtain a functional high affinity nitrate system in Chlamydomonas [Quesada et al. (1994) Plant J. 5, 407-419]. In this paper we have tested this hypothesis by injecting Xenopus oocytes with mRNA prepared from these two cDNAs, Nrt2;1 and Nar2, and then assaying the oocytes for nitrate transport activity. Oocytes injected with single types of mRNA did not show any nitrate transport activity. Furthermore, Nar2 mRNA was toxic to oocytes, with nearly 60%, of the oocytes dead 3 days after the injection. However, when oocytes were injected with a mixture of two mRNAs prepared from Nrt2;1 and Nar2, a high affinity nitrate transport activity could be measured. However, the Km for nitrate of this transport system was 28 microM which is higher than the value of 1.6 microM which had been obtained by the analysis of mutant phenotypes. The pH-dependence of the nitrate-elicited currents was consistent with a proton-cotransport mechanism. These results prove that two gene products are required to produce a functional high affinity nitrate transport system and that this process does not involve transcriptional regulation.
Collapse
Affiliation(s)
- J J Zhou
- Biochemistry and Physiology Department, IACR-Rothamsted, Harpenden, UK
| | | | | | | |
Collapse
|
26
|
Navarro MT, Guerra E, Fernández E, Galván A. Nitrite reductase mutants as an approach to understanding nitrate assimilation in Chlamydomonas reinhardtii. PLANT PHYSIOLOGY 2000; 122:283-90. [PMID: 10631272 PMCID: PMC58867 DOI: 10.1104/pp.122.1.283] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/1999] [Accepted: 09/24/1999] [Indexed: 05/18/2023]
Abstract
We constructed mutant strains lacking the nitrite reductase (NR) gene in Chlamydomonas reinhardtii. Two types of NR mutants were obtained, which either have or lack the high-affinity nitrate transporter (Nrt2;1, Nrt2;2, and Nar2) genes. None of these mutants overexpressed nitrate assimilation gene transcripts nor NR activity in nitrogen-free medium, in contrast to NR mutants. This finding confirms the previous role proposed for NR on its own regulation (autoregulation) and on the other genes for nitrate assimilation in C. reinhardtii. In addition, the NR mutants were used to study nitrate transporters from nitrite excretion. At high CO(2), only strains carrying the above high-affinity nitrate transporter genes excreted stoichiometric amounts of nitrite from 100 microM nitrate in the medium. A double mutant, deficient in both the high-affinity nitrate transporter genes and NR, excreted nitrite at high CO(2) only when nitrate was present at mM concentrations. This suggests that there exists a low-affinity nitrate transporter that might correspond to the nitrate/nitrite transport system III. Moreover, under low CO(2) conditions, the double mutant excreted nitrite from nitrate at micromolar concentrations by a transporter with the properties of the nitrate/nitrite transport system IV.
Collapse
Affiliation(s)
- M T Navarro
- Departamento de Bioquímica y Biología Molecular and Instituto Andaluz de Biotecnología, Avda. San Alberto Magno, Facultad de Ciencias, Universidad de Córdoba, 14071-Córdoba, Spain
| | | | | | | |
Collapse
|