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Hahn V, Zühlke D, Winter H, Landskron A, Bernhardt J, Sievers S, Schmidt M, von Woedtke T, Riedel K, Kolb JF. Proteomic profiling of antibiotic-resistant Escherichia coli GW-AmxH19 isolated from hospital wastewater treated with physical plasma. Proteomics 2024:e2300494. [PMID: 38644344 DOI: 10.1002/pmic.202300494] [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: 11/03/2023] [Revised: 03/29/2024] [Accepted: 04/04/2024] [Indexed: 04/23/2024]
Abstract
Microorganisms which are resistant to antibiotics are a global threat to the health of humans and animals. Wastewater treatment plants are known hotspots for the dissemination of antibiotic resistances. Therefore, novel methods for the inactivation of pathogens, and in particular antibiotic-resistant microorganisms (ARM), are of increasing interest. An especially promising method could be a water treatment by physical plasma which provides charged particles, electric fields, UV-radiation, and reactive species. The latter are foremost responsible for the antimicrobial properties of plasma. Thus, with plasma it might be possible to reduce the amount of ARM and to establish this technology as additional treatment stage for wastewater remediation. However, the impact of plasma on microorganisms beyond a mere inactivation was analyzed in more detail by a proteomic approach. Therefore, Escherichia coli GW-AmxH19, isolated from hospital wastewater in Germany, was used. The bacterial solution was treated by a plasma discharge ignited between each of four pins and the liquid surface. The growth of E. coli and the pH-value decreased during plasma treatment in comparison with the untreated control. Proteome and antibiotic resistance profile were analyzed. Concentrations of nitrite and nitrate were determined as long-lived indicative products of a transient chemistry associated with reactive nitrogen species (RNS). Conversely, hydrogen peroxide served as indicator for reactive oxygen species (ROS). Proteome analyses revealed an oxidative stress response as a result of plasma-generated RNS and ROS as well as a pH-balancing reaction as key responses to plasma treatment. Both, the generation of reactive species and a decreased pH-value is characteristic for plasma-treated solutions. The plasma-mediated changes of the proteome are discussed also in comparison with the Gram-positive bacterium Bacillus subtilis. Furthermore, no effect of the plasma treatment, on the antibiotic resistance of E. coli, was determined under the chosen conditions. The knowledge about the physiological changes of ARM in response to plasma is of fundamental interest to understand the molecular basis for the inactivation. This will be important for the further development and implementation of plasma in wastewater remediation.
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Affiliation(s)
- Veronika Hahn
- Leibniz Institute for Plasma Science and Technology (INP), Greifswald, Germany
| | - Daniela Zühlke
- Institute of Marine Biotechnology, Greifswald, Germany
- Department of Microbial Physiology and Molecular Biology, Institute of Microbiology, University of Greifswald, Greifswald, Germany
| | - Hauke Winter
- Leibniz Institute for Plasma Science and Technology (INP), Greifswald, Germany
- Department of Microbial Physiology and Molecular Biology, Institute of Microbiology, University of Greifswald, Greifswald, Germany
| | - Annchristin Landskron
- Leibniz Institute for Plasma Science and Technology (INP), Greifswald, Germany
- Department of Microbial Physiology and Molecular Biology, Institute of Microbiology, University of Greifswald, Greifswald, Germany
| | - Jörg Bernhardt
- Department of Microbial Physiology and Molecular Biology, Institute of Microbiology, University of Greifswald, Greifswald, Germany
| | - Susanne Sievers
- Department of Microbial Physiology and Molecular Biology, Institute of Microbiology, University of Greifswald, Greifswald, Germany
| | - Michael Schmidt
- Leibniz Institute for Plasma Science and Technology (INP), Greifswald, Germany
| | - Thomas von Woedtke
- Leibniz Institute for Plasma Science and Technology (INP), Greifswald, Germany
- Institute for Hygiene and Environmental Medicine, Greifswald University Medicine, Greifswald, Germany
| | - Katharina Riedel
- Institute of Marine Biotechnology, Greifswald, Germany
- Department of Microbial Physiology and Molecular Biology, Institute of Microbiology, University of Greifswald, Greifswald, Germany
| | - Juergen F Kolb
- Leibniz Institute for Plasma Science and Technology (INP), Greifswald, Germany
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Khan S, Ansari A, Brachi M, Das D, El Housseini W, Minteer S, Miller AF. Structure, dynamics, and redox reactivity of an all-purpose flavodoxin. J Biol Chem 2024; 300:107122. [PMID: 38417793 PMCID: PMC10979112 DOI: 10.1016/j.jbc.2024.107122] [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: 12/13/2023] [Revised: 02/15/2024] [Accepted: 02/21/2024] [Indexed: 03/01/2024] Open
Abstract
The flavodoxin of Rhodopseudomonas palustris CGA009 (Rp9Fld) supplies highly reducing equivalents to crucial enzymes such as hydrogenase, especially when the organism is iron-restricted. By acquiring those electrons from photodriven electron flow via the bifurcating electron transfer flavoprotein, Rp9Fld provides solar power to vital metabolic processes. To understand Rp9Fld's ability to work with diverse partners, we solved its crystal structure. We observed the canonical flavodoxin (Fld) fold and features common to other long-chain Flds but not all the surface loops thought to recognize partner proteins. Moreover, some of the loops display alternative structures and dynamics. To advance studies of protein-protein associations and conformational consequences, we assigned the 19F NMR signals of all five tyrosines (Tyrs). Our electrochemical measurements show that incorporation of 3-19F-Tyr in place of Tyr has only a modest effect on Rp9Fld's redox properties even though Tyrs flank the flavin on both sides. Meanwhile, the 19F probes demonstrate the expected paramagnetic effect, with signals from nearby Tyrs becoming broadened beyond detection when the flavin semiquinone is formed. However, the temperature dependencies of chemical shifts and linewidths reveal dynamics affecting loops close to the flavin and regions that bind to partners in a variety of systems. These coincide with patterns of amino acid type conservation but not retention of specific residues, arguing against detailed specificity with respect to partners. We propose that the loops surrounding the flavin adopt altered conformations upon binding to partners and may even participate actively in electron transfer.
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Affiliation(s)
- Sharique Khan
- Department of Chemistry, University of Kentucky, Lexington, Kentucky, USA
| | - Ahmadullah Ansari
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
| | - Monica Brachi
- Department of Chemistry, University of Utah, Salt Lake City, Utah, USA
| | - Debarati Das
- Department of Chemistry, University of Kentucky, Lexington, Kentucky, USA
| | | | - Shelley Minteer
- Department of Chemistry, University of Utah, Salt Lake City, Utah, USA; Department of Chemistry, Kummer Institute Center for Resource Sustainability, Missouri University of Science and Technology, Rolla, Missouri, USA
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Rodríguez-Castro L, Durán RE, Méndez V, Dorochesi F, Zühlke D, Riedel K, Seeger M. The long-chain flavodoxin FldX1 improves the biodegradation of 4-hydroxyphenylacetate and 3-hydroxyphenylacetate and counteracts the oxidative stress associated to aromatic catabolism in Paraburkholderia xenovorans. Biol Res 2024; 57:12. [PMID: 38561836 PMCID: PMC10983741 DOI: 10.1186/s40659-024-00491-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Accepted: 03/20/2024] [Indexed: 04/04/2024] Open
Abstract
BACKGROUND Bacterial aromatic degradation may cause oxidative stress. The long-chain flavodoxin FldX1 of Paraburkholderia xenovorans LB400 counteracts reactive oxygen species (ROS). The aim of this study was to evaluate the protective role of FldX1 in P. xenovorans LB400 during the degradation of 4-hydroxyphenylacetate (4-HPA) and 3-hydroxyphenylacetate (3-HPA). METHODS The functionality of FldX1 was evaluated in P. xenovorans p2-fldX1 that overexpresses FldX1. The effects of FldX1 on P. xenovorans were studied measuring growth on hydroxyphenylacetates, degradation of 4-HPA and 3-HPA, and ROS formation. The effects of hydroxyphenylacetates (HPAs) on the proteome (LC-MS/MS) and gene expression (qRT-PCR) were quantified. Bioaugmentation with strain p2-fldX1 of 4-HPA-polluted soil was assessed, measuring aromatic degradation (HPLC), 4-HPA-degrading bacteria, and plasmid stability. RESULTS The exposure of P. xenovorans to 4-HPA increased the formation of ROS compared to 3-HPA or glucose. P. xenovorans p2-fldX1 showed an increased growth on 4-HPA and 3-HPA compared to the control strain WT-p2. Strain p2-fldX1 degraded faster 4-HPA and 3-HPA than strain WT-p2. Both WT-p2 and p2-fldX1 cells grown on 4-HPA displayed more changes in the proteome than cells grown on 3-HPA in comparison to glucose-grown cells. Several enzymes involved in ROS detoxification, including AhpC2, AhpF, AhpD3, KatA, Bcp, CpoF1, Prx1 and Prx2, were upregulated by hydroxyphenylacetates. Downregulation of organic hydroperoxide resistance (Ohr) and DpsA proteins was observed. A downregulation of the genes encoding scavenging enzymes (katE and sodB), and gstA and trxB was observed in p2-fldX1 cells, suggesting that FldX1 prevents the antioxidant response. More than 20 membrane proteins, including porins and transporters, showed changes in expression during the growth of both strains on hydroxyphenylacetates. An increased 4-HPA degradation by recombinant strain p2-fldX1 in soil microcosms was observed. In soil, the strain overexpressing the flavodoxin FldX1 showed a lower plasmid loss, compared to WT-p2 strain, suggesting that FldX1 contributes to bacterial fitness. Overall, these results suggest that recombinant strain p2-fldX1 is an attractive bacterium for its application in bioremediation processes of aromatic compounds. CONCLUSIONS The long-chain flavodoxin FldX1 improved the capability of P. xenovorans to degrade 4-HPA in liquid culture and soil microcosms by protecting cells against the degradation-associated oxidative stress.
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Affiliation(s)
- Laura Rodríguez-Castro
- Laboratorio de Microbiología Molecular y Biotecnología Ambiental, Departamento de Química & Centro de Biotecnología Daniel Alkalay Lowitt, Universidad Técnica Federico Santa María, Avenida España 1680, 2390123, Valparaíso, Chile
| | - Roberto E Durán
- Laboratorio de Microbiología Molecular y Biotecnología Ambiental, Departamento de Química & Centro de Biotecnología Daniel Alkalay Lowitt, Universidad Técnica Federico Santa María, Avenida España 1680, 2390123, Valparaíso, Chile
- Millenium Nucleus Bioproducts, Genomics and Environmental Genomics (BioGEM), Avenida España 1680, 2390123, Valparaíso, Chile
| | - Valentina Méndez
- Laboratorio de Microbiología Molecular y Biotecnología Ambiental, Departamento de Química & Centro de Biotecnología Daniel Alkalay Lowitt, Universidad Técnica Federico Santa María, Avenida España 1680, 2390123, Valparaíso, Chile
- Millenium Nucleus Bioproducts, Genomics and Environmental Genomics (BioGEM), Avenida España 1680, 2390123, Valparaíso, Chile
| | - Flavia Dorochesi
- Laboratorio de Microbiología Molecular y Biotecnología Ambiental, Departamento de Química & Centro de Biotecnología Daniel Alkalay Lowitt, Universidad Técnica Federico Santa María, Avenida España 1680, 2390123, Valparaíso, Chile
| | - Daniela Zühlke
- Institute of Microbiology, University of Greifswald, Felix-Hausdorff-Strasse 8, 17489, Greifswald, Germany
| | - Katharina Riedel
- Institute of Microbiology, University of Greifswald, Felix-Hausdorff-Strasse 8, 17489, Greifswald, Germany
| | - Michael Seeger
- Laboratorio de Microbiología Molecular y Biotecnología Ambiental, Departamento de Química & Centro de Biotecnología Daniel Alkalay Lowitt, Universidad Técnica Federico Santa María, Avenida España 1680, 2390123, Valparaíso, Chile.
- Millenium Nucleus Bioproducts, Genomics and Environmental Genomics (BioGEM), Avenida España 1680, 2390123, Valparaíso, Chile.
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Troitzsch D, Knop R, Dittmann S, Bartel J, Zühlke D, Möller TA, Trän L, Echelmeyer T, Sievers S. Characterizing the flavodoxin landscape in Clostridioides difficile. Microbiol Spectr 2024; 12:e0189523. [PMID: 38319052 PMCID: PMC10913485 DOI: 10.1128/spectrum.01895-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Accepted: 12/23/2023] [Indexed: 02/07/2024] Open
Abstract
Clostridioides difficile infections have become a major challenge in medical facilities. The bacterium is capable of spore formation allowing the survival of antibiotic treatment. Therefore, research on the physiology of C. difficile is important for the development of alternative treatment strategies. In this study, we investigated eight putative flavodoxins of C. difficile 630. Flavodoxins are small electron transfer proteins of specifically low potential. The unusually high number of flavodoxins in C. difficile suggests that they are expressed under different conditions. We determined high transcription levels for several flavodoxins during the exponential growth phase, especially for floX. Since flavodoxins are capable of replacing ferredoxins under iron deficiency conditions in other bacteria, we also examined their expression in C. difficile under low iron and no iron levels. In particular, the amount of fldX increased with decreasing iron concentration and thus could possibly replace ferredoxins. Moreover, we demonstrated that fldX is increasingly expressed under different oxidative stress conditions and thus may play an important role in the oxidative stress response. While increased fldX expression was detectable at both RNA and protein level, CD2825 showed increased expression only at mRNA level under H2O2 stress with sufficient iron availability and may indicate hydroxyl radical-dependent transcription. Although the exact function of the individual flavodoxins in C. difficile needs to be further investigated, the present study shows that flavodoxins could play an important role in several physiological processes and under infection-relevant conditions. IMPORTANCE The gram-positive, anaerobic, and spore-forming bacterium Clostridioides difficile has become a vast problem in human health care facilities. The antibiotic-associated infection with this intestinal pathogen causes serious and recurrent inflammation of the intestinal epithelium, in many cases with a severe course. To come up with novel targeted therapies against C. difficile infections, a more detailed knowledge on the pathogen's physiology is mandatory. Eight putative flavodoxins, an extraordinarily high copy number of this type of small electron transfer proteins, are annotated for C. difficile. Flavodoxins are known to be essential electron carriers in other bacteria, for instance, during infection-relevant conditions such as iron limitation and oxidative stress. This work is a first and comprehensive overview on characteristics and expression profiles of the putative flavodoxins in the pathogen C. difficile.
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Affiliation(s)
- Daniel Troitzsch
- Department of Microbial Physiology and Molecular Biology, Institute of Microbiology, University of Greifswald, Greifswald, Germany
| | - Robert Knop
- Department of Microbial Physiology and Molecular Biology, Institute of Microbiology, University of Greifswald, Greifswald, Germany
| | - Silvia Dittmann
- Department of Microbial Physiology and Molecular Biology, Institute of Microbiology, University of Greifswald, Greifswald, Germany
| | - Jürgen Bartel
- Department of Microbial Proteomics, Institute of Microbiology, University of Greifswald, Greifswald, Germany
| | - Daniela Zühlke
- Department of Microbial Physiology and Molecular Biology, Institute of Microbiology, University of Greifswald, Greifswald, Germany
| | - Timon Alexander Möller
- Department of Microbial Physiology and Molecular Biology, Institute of Microbiology, University of Greifswald, Greifswald, Germany
| | - Linda Trän
- Department of Microbial Physiology and Molecular Biology, Institute of Microbiology, University of Greifswald, Greifswald, Germany
| | - Thaddäus Echelmeyer
- Department of Microbial Physiology and Molecular Biology, Institute of Microbiology, University of Greifswald, Greifswald, Germany
| | - Susanne Sievers
- Department of Microbial Physiology and Molecular Biology, Institute of Microbiology, University of Greifswald, Greifswald, Germany
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5
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Zhao G, Liu Y, Li L, Che R, Douglass M, Benza K, Angove M, Luo K, Hu Q, Chen X, Henry C, Li Z, Ning G, Luo H. Gene pyramiding for boosted plant growth and broad abiotic stress tolerance. PLANT BIOTECHNOLOGY JOURNAL 2024; 22:678-697. [PMID: 37902192 PMCID: PMC10893947 DOI: 10.1111/pbi.14216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2022] [Revised: 09/24/2023] [Accepted: 10/16/2023] [Indexed: 10/31/2023]
Abstract
Abiotic stresses such as salinity, heat and drought seriously impair plant growth and development, causing a significant loss in crop yield and ornamental value. Biotechnology approaches manipulating specific genes prove to be effective strategies in crop trait modification. The Arabidopsis vacuolar pyrophosphatase gene AVP1, the rice SUMO E3 ligase gene OsSIZ1 and the cyanobacterium flavodoxin gene Fld have previously been implicated in regulating plant stress responses and conferring enhanced tolerance to different abiotic stresses when individually overexpressed in various plant species. We have explored the feasibility of combining multiple favourable traits brought by individual genes to acquire superior plant performance. To this end, we have simultaneously introduced AVP1, OsSIZ1 and Fld in creeping bentgrass. Transgenic (TG) plants overexpressing these three genes performed significantly better than wild type controls and the TGs expressing individual genes under both normal and various abiotic stress conditions, exhibited significantly enhanced plant growth and tolerance to drought, salinity and heat stresses as well as nitrogen and phosphate starvation, which were associated with altered physiological and biochemical characteristics and delicately fine-tuned expression of genes involved in plant stress responses. Our results suggest that AVP1, OsSIZ1 and Fld function synergistically to regulate plant development and plant stress response, leading to superior overall performance under both normal and adverse environments. The information obtained provides new insights into gene stacking as an effective approach for plant genetic engineering. A similar strategy can be extended for the use of other beneficial genes in various crop species for trait modifications, enhancing agricultural production.
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Affiliation(s)
- Guiqin Zhao
- Department of Genetics and BiochemistryClemson UniversityClemsonSCUSA
- College of Grassland ScienceGansu Agricultural UniversityLanzhouGansuChina
| | - Yu Liu
- Department of Genetics and BiochemistryClemson UniversityClemsonSCUSA
- College of Landscape ArchitectureNortheast Forestry UniversityHarbinHeilongjiangChina
| | - Lei Li
- Department of Genetics and BiochemistryClemson UniversityClemsonSCUSA
- College of AgronomyHenan Agricultural UniversityZhengzhouHenanChina
| | - Rui Che
- Department of Genetics and BiochemistryClemson UniversityClemsonSCUSA
| | - Megan Douglass
- Department of Genetics and BiochemistryClemson UniversityClemsonSCUSA
| | - Katherine Benza
- Department of Genetics and BiochemistryClemson UniversityClemsonSCUSA
| | - Mitchell Angove
- Department of Genetics and BiochemistryClemson UniversityClemsonSCUSA
| | - Kristopher Luo
- Department of Genetics and BiochemistryClemson UniversityClemsonSCUSA
| | - Qian Hu
- Department of Genetics and BiochemistryClemson UniversityClemsonSCUSA
| | - Xiaotong Chen
- Department of Genetics and BiochemistryClemson UniversityClemsonSCUSA
| | - Charles Henry
- Department of Genetics and BiochemistryClemson UniversityClemsonSCUSA
| | - Zhigang Li
- Department of Genetics and BiochemistryClemson UniversityClemsonSCUSA
| | - Guogui Ning
- Key laboratory of Horticultural Plant Biology, Ministry of EducationHuazhong Agricultural UniversityWuhanChina
| | - Hong Luo
- Department of Genetics and BiochemistryClemson UniversityClemsonSCUSA
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Palavecino A, Sartorio MG, Carrillo N, Cortez N, Bortolotti A. The extremophilic Andean isolate Acinetobacter sp. Ver3 expresses two ferredoxin-NADP + reductase isoforms with different catalytic properties. FEBS Lett 2024; 598:670-683. [PMID: 38433717 DOI: 10.1002/1873-3468.14826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Revised: 01/04/2024] [Accepted: 01/06/2024] [Indexed: 03/05/2024]
Abstract
Ferredoxin/flavodoxin-NADPH reductases (FPRs) catalyze the reversible electron transfer between NADPH and ferredoxin/flavodoxin. The Acinetobacter sp. Ver3 isolated from high-altitude Andean lakes contains two isoenzymes, FPR1ver3 and FPR2ver3. Absorption spectra of these FPRs revealed typical features of flavoproteins, consistent with the use of FAD as a prosthetic group. Spectral differences indicate distinct electronic arrangements for the flavin in each enzyme. Steady-state kinetic measurements show that the enzymes display catalytic efficiencies in the order of 1-6 μm-1·s-1, although FPR1ver3 exhibited higher kcat values compared to FPR2ver3. When flavodoxinver3 was used as a substrate, both reductases exhibited dissimilar behavior. Moreover, only FPR1ver3 is induced by oxidative stimuli, indicating that the polyextremophile Ver3 has evolved diverse strategies to cope with oxidative environments.
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Affiliation(s)
- Alejandro Palavecino
- Facultad de Ciencias Bioquímicas y Farmacéuticas, Instituto de Biología Molecular y Celular de Rosario (UNR & CONICET), Universidad Nacional de Rosario, Argentina
| | - Mariana Gabriela Sartorio
- Facultad de Ciencias Bioquímicas y Farmacéuticas, Instituto de Biología Molecular y Celular de Rosario (UNR & CONICET), Universidad Nacional de Rosario, Argentina
| | - Néstor Carrillo
- Facultad de Ciencias Bioquímicas y Farmacéuticas, Instituto de Biología Molecular y Celular de Rosario (UNR & CONICET), Universidad Nacional de Rosario, Argentina
| | - Néstor Cortez
- Facultad de Ciencias Bioquímicas y Farmacéuticas, Instituto de Biología Molecular y Celular de Rosario (UNR & CONICET), Universidad Nacional de Rosario, Argentina
| | - Ana Bortolotti
- Área Biofísica, Departamento de Química Biológica, Facultad de Ciencias Bioquímicas y Farmacéuticas., Universidad Nacional de Rosario (UNR & CONICET), Rosario, Argentina
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7
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Demarchi M, Arce RC, Campi M, Pierella Karlusich JJ, Hajirezaei MR, Melzer M, Lodeyro AF, Chan RL, Carrillo N. Targeting of flavodoxin to chloroplasts of mesophyll but not bundle sheath maize cells confers increased drought tolerance. THE NEW PHYTOLOGIST 2023; 240:2179-2184. [PMID: 37814446 DOI: 10.1111/nph.19281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Accepted: 08/28/2023] [Indexed: 10/11/2023]
Affiliation(s)
- Mariana Demarchi
- Instituto de Biología Molecular y Celular de Rosario (IBR-UNR/CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario (UNR), 2000, Rosario, Argentina
| | - Rocío C Arce
- Instituto de Biología Molecular y Celular de Rosario (IBR-UNR/CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario (UNR), 2000, Rosario, Argentina
| | - Mabel Campi
- Instituto de Agrobiotecnología del Litoral (IAL-UNL/CONICET), Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral (UNL), 3000, Santa Fe, Argentina
| | - Juan J Pierella Karlusich
- Instituto de Biología Molecular y Celular de Rosario (IBR-UNR/CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario (UNR), 2000, Rosario, Argentina
| | - Mohammad-Reza Hajirezaei
- Leibniz Institute of Plant Genetics and Crop Plant Research, OT Gatersleben, Corrensstrasse, D-06466, Stadt Seeland, Germany
| | - Michael Melzer
- Leibniz Institute of Plant Genetics and Crop Plant Research, OT Gatersleben, Corrensstrasse, D-06466, Stadt Seeland, Germany
| | - Anabella F Lodeyro
- Instituto de Biología Molecular y Celular de Rosario (IBR-UNR/CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario (UNR), 2000, Rosario, Argentina
| | - Raquel L Chan
- Instituto de Agrobiotecnología del Litoral (IAL-UNL/CONICET), Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral (UNL), 3000, Santa Fe, Argentina
| | - Néstor Carrillo
- Instituto de Biología Molecular y Celular de Rosario (IBR-UNR/CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario (UNR), 2000, Rosario, Argentina
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8
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Gwak JH, Awala SI, Kim SJ, Lee SH, Yang EJ, Park J, Jung J, Rhee SK. Transcriptomic Insights into Archaeal Nitrification in the Amundsen Sea Polynya, Antarctica. J Microbiol 2023; 61:967-980. [PMID: 38062325 DOI: 10.1007/s12275-023-00090-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2023] [Revised: 09/27/2023] [Accepted: 10/23/2023] [Indexed: 12/19/2023]
Abstract
Antarctic polynyas have the highest Southern Ocean summer primary productivity, and due to anthropogenic climate change, these areas have formed faster recently. Ammonia-oxidizing archaea (AOA) are among the most ubiquitous and abundant microorganisms in the ocean and play a primary role in the global nitrogen cycle. We utilized metagenomics and metatranscriptomics to gain insights into the physiology and metabolism of AOA in polar oceans, which are associated with ecosystem functioning. A polar-specific ecotype of AOA, from the "Candidatus Nitrosomarinus"-like group, was observed to be dominant in the Amundsen Sea Polynya (ASP), West Antarctica, during a succession of summer phytoplankton blooms. AOA had the highest transcriptional activity among prokaryotes during the bloom decline phase (DC). Metatranscriptomic analysis of key genes involved in ammonia oxidation, carbon fixation, transport, and cell division indicated that this polar AOA ecotype was actively involved in nitrification in the bloom DC in the ASP. This study revealed the physiological and metabolic traits of this key polar-type AOA in response to phytoplankton blooms in the ASP and provided insights into AOA functions in polar oceans.
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Affiliation(s)
- Joo-Han Gwak
- Department of Biological Sciences and Biotechnology, Chungbuk National University, Cheongju, 28644, Republic of Korea
| | - Samuel Imisi Awala
- Department of Biological Sciences and Biotechnology, Chungbuk National University, Cheongju, 28644, Republic of Korea
| | - So-Jeong Kim
- Geologic Environment Division, Korea Institute of Geoscience and Mineral Resources, Daejeon, 34132, Republic of Korea
| | - Sang-Hoon Lee
- Korea Polar Research Institute, Incheon, 21990, Republic of Korea
| | - Eun-Jin Yang
- Korea Polar Research Institute, Incheon, 21990, Republic of Korea
| | - Jisoo Park
- Korea Polar Research Institute, Incheon, 21990, Republic of Korea
| | - Jinyoung Jung
- Korea Polar Research Institute, Incheon, 21990, Republic of Korea
| | - Sung-Keun Rhee
- Department of Biological Sciences and Biotechnology, Chungbuk National University, Cheongju, 28644, Republic of Korea.
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9
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Truong A, Myerscough D, Campbell I, Atkinson J, Silberg JJ. A cellular selection identifies elongated flavodoxins that support electron transfer to sulfite reductase. Protein Sci 2023; 32:e4746. [PMID: 37551563 PMCID: PMC10503412 DOI: 10.1002/pro.4746] [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: 03/25/2023] [Revised: 07/17/2023] [Accepted: 08/04/2023] [Indexed: 08/09/2023]
Abstract
Flavodoxins (Flds) mediate the flux of electrons between oxidoreductases in diverse metabolic pathways. To investigate whether Flds can support electron transfer to a sulfite reductase (SIR) that evolved to couple with a ferredoxin, we evaluated the ability of Flds to transfer electrons from a ferredoxin-NADP reductase (FNR) to a ferredoxin-dependent SIR using growth complementation of an Escherichia coli strain with a sulfur metabolism defect. We show that Flds from cyanobacteria complement this growth defect when coexpressed with an FNR and an SIR that evolved to couple with a plant ferredoxin. When we evaluated the effect of peptide insertion on Fld-mediated electron transfer, we observed a sensitivity to insertions within regions predicted to be proximal to the cofactor and partner binding sites, while a high insertion tolerance was detected within loops distal from the cofactor and within regions of helices and sheets that are proximal to those loops. Bioinformatic analysis showed that natural Fld sequence variability predicts a large fraction of the motifs that tolerate insertion of the octapeptide SGRPGSLS. These results represent the first evidence that Flds can support electron transfer to assimilatory SIRs, and they suggest that the pattern of insertion tolerance is influenced by interactions with oxidoreductase partners.
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Affiliation(s)
- Albert Truong
- Biochemistry and Cell Biology Graduate Program, Rice University, Houston, Texas, USA
- Department of Biosciences, Rice University, Houston, Texas, USA
| | - Dru Myerscough
- Department of Biosciences, Rice University, Houston, Texas, USA
| | - Ian Campbell
- Department of Biosciences, Rice University, Houston, Texas, USA
| | - Joshua Atkinson
- Department of Biosciences, Rice University, Houston, Texas, USA
| | - Jonathan J Silberg
- Department of Biosciences, Rice University, Houston, Texas, USA
- Department of Bioengineering, Rice University, Houston, Texas, USA
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas, USA
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10
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Lewis JP, Gui Q. Iron Deficiency Modulates Metabolic Landscape of Bacteroidetes Promoting Its Resilience during Inflammation. Microbiol Spectr 2023; 11:e0473322. [PMID: 37314331 PMCID: PMC10434189 DOI: 10.1128/spectrum.04733-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Accepted: 05/05/2023] [Indexed: 06/15/2023] Open
Abstract
Bacteria have to persist under low iron conditions in order to adapt to the nutritional immunity of a host. Since the knowledge of iron stimulon of Bacteroidetes is sparse, we examined oral (Porphyromonas gingivalis and Prevotella intermedia) and gut (Bacteroides thataiotaomicron) representatives for their ability to adapt to iron deplete and iron replete conditions. Our transcriptomics and comparative genomics analysis show that many iron-regulated mechanisms are conserved within the phylum. They include genes upregulated in low iron, as follows: fldA (flavodoxin), hmu (hemin uptake operon), and loci encoding ABC transporters. Downregulated genes were frd (ferredoxin), rbr (rubrerythrin), sdh (succinate dehydrogenase/fumarate reductase), vor (oxoglutarate oxidoreductase/dehydrogenase), and pfor (pyruvate:ferredoxin/flavodoxin oxidoreductase). Some genus-specific mechanisms, such as the sus of B. thetaiotaomicron coding for carbohydrate metabolism and the xusABC coding for xenosiderophore utilization were also identified. While all bacteria tested in our study had the nrfAH operon coding for nitrite reduction and were able to reduce nitrite levels present in culture media, the expression of the operon was iron dependent only in B. thetaiotaomicron. It is noteworthy that we identified a significant overlap between regulated genes found in our study and the B. thetaiotaomicron colitis study (W. Zhu, M. G. Winter, L. Spiga, E. R. Hughes et al., Cell Host Microbe 27:376-388, 2020, http://dx.doi.org/10.1016/j.chom.2020.01.010). Many of those commonly regulated genes were also iron regulated in the oral bacterial genera. Overall, this work points to iron being the master regulator enabling bacterial persistence in the host and paves the way for a more generalized investigation of the molecular mechanisms of iron homeostasis in Bacteroidetes. IMPORTANCE Bacteroidetes are an important group of anaerobic bacteria abundant both in the oral and gut microbiomes. Although iron is a required nutrient for most living organisms, the molecular mechanisms of adaptation to the changing levels of iron are not well known in this group of bacteria. We defined the iron stimulon of Bacteroidetes by examination of the transcriptomic response of Porphyromonas gingivalis and Prevotella intermedia (both belong to the oral microbiome) and Bacteroidetes thetaiotaomicron (belongs to the gut microbiome). Our results indicate that many of the iron-regulated operons are shared among the three genera. Furthermore, using bioinformatics analysis, we identified a significant overlap between our in vitro studies and transcriptomic data derived from a colitis study, thus underscoring the biological significance of our work. Defining the iron-dependent stimulon of Bacteroidetes can help to identify the molecular mechanisms of iron-dependent regulation as well as better understand the persistence of the anaerobes in the human host.
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Affiliation(s)
- Janina P. Lewis
- Philips Institute for Oral Health Research, Virginia Commonwealth University, Richmond, Virginia, USA
- Department of Microbiology and Immunology, Virginia Commonwealth University, Richmond, Virginia, USA
- Department of Biochemistry, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Qin Gui
- Philips Institute for Oral Health Research, Virginia Commonwealth University, Richmond, Virginia, USA
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11
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Molinari PE, Krapp AR, Zurbriggen MD, Carrillo N. Lighting the light reactions of photosynthesis by means of redox-responsive genetically encoded biosensors for photosynthetic intermediates. Photochem Photobiol Sci 2023; 22:2005-2018. [PMID: 37195389 DOI: 10.1007/s43630-023-00425-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Accepted: 04/17/2023] [Indexed: 05/18/2023]
Abstract
Oxygenic photosynthesis involves light and dark phases. In the light phase, photosynthetic electron transport provides reducing power and energy to support the carbon assimilation process. It also contributes signals to defensive, repair, and metabolic pathways critical for plant growth and survival. The redox state of components of the photosynthetic machinery and associated routes determines the extent and direction of plant responses to environmental and developmental stimuli, and therefore, their space- and time-resolved detection in planta becomes critical to understand and engineer plant metabolism. Until recently, studies in living systems have been hampered by the inadequacy of disruptive analytical methods. Genetically encoded indicators based on fluorescent proteins provide new opportunities to illuminate these important issues. We summarize here information about available biosensors designed to monitor the levels and redox state of various components of the light reactions, including NADP(H), glutathione, thioredoxin, and reactive oxygen species. Comparatively few probes have been used in plants, and their application to chloroplasts poses still additional challenges. We discuss advantages and limitations of biosensors based on different principles and propose rationales for the design of novel probes to estimate the NADP(H) and ferredoxin/flavodoxin redox poise, as examples of the exciting questions that could be addressed by further development of these tools. Genetically encoded fluorescent biosensors are remarkable tools to monitor the levels and/or redox state of components of the photosynthetic light reactions and accessory pathways. Reducing equivalents generated at the photosynthetic electron transport chain in the form of NADPH and reduced ferredoxin (FD) are used in central metabolism, regulation, and detoxification of reactive oxygen species (ROS). Redox components of these pathways whose levels and/or redox status have been imaged in plants using biosensors are highlighted in green (NADPH, glutathione, H2O2, thioredoxins). Analytes with available biosensors not tried in plants are shown in pink (NADP+). Finally, redox shuttles with no existing biosensors are circled in light blue. APX, ASC peroxidase; ASC, ascorbate; DHA, dehydroascorbate; DHAR, DHA reductase; FNR, FD-NADP+ reductase; FTR, FD-TRX reductase; GPX, glutathione peroxidase; GR, glutathione reductase; GSH, reduced glutathione; GSSG, oxidized glutathione; MDA, monodehydroascorbate; MDAR, MDA reductase; NTRC, NADPH-TRX reductase C; OAA, oxaloacetate; PRX, peroxiredoxin; PSI, photosystem I; PSII: photosystem II; SOD, superoxide dismutase; TRX, thioredoxin.
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Affiliation(s)
- Pamela E Molinari
- Instituto de Biología Molecular y Celular de Rosario (UNR/CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina
| | - Adriana R Krapp
- Instituto de Biología Molecular y Celular de Rosario (UNR/CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina
| | - Matias D Zurbriggen
- Institute of Synthetic Biology and CEPLAS, University of Düsseldorf, Düsseldorf, Germany
| | - Néstor Carrillo
- Instituto de Biología Molecular y Celular de Rosario (UNR/CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina.
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12
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Mellor SB, Behrendorff JBYH, Ipsen JØ, Crocoll C, Laursen T, Gillam EMJ, Pribil M. Exploiting photosynthesis-driven P450 activity to produce indican in tobacco chloroplasts. FRONTIERS IN PLANT SCIENCE 2023; 13:1049177. [PMID: 36743583 PMCID: PMC9890960 DOI: 10.3389/fpls.2022.1049177] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Accepted: 12/14/2022] [Indexed: 05/28/2023]
Abstract
Photosynthetic organelles offer attractive features for engineering small molecule bioproduction by their ability to convert solar energy into chemical energy required for metabolism. The possibility to couple biochemical production directly to photosynthetic assimilation as a source of energy and substrates has intrigued metabolic engineers. Specifically, the chemical diversity found in plants often relies on cytochrome P450-mediated hydroxylations that depend on reductant supply for catalysis and which often lead to metabolic bottlenecks for heterologous production of complex molecules. By directing P450 enzymes to plant chloroplasts one can elegantly deal with such redox prerequisites. In this study, we explore the capacity of the plant photosynthetic machinery to drive P450-dependent formation of the indigo precursor indoxyl-β-D-glucoside (indican) by targeting an engineered indican biosynthetic pathway to tobacco (Nicotiana benthamiana) chloroplasts. We show that both native and engineered variants belonging to the human CYP2 family are catalytically active in chloroplasts when driven by photosynthetic reducing power and optimize construct designs to improve productivity. However, while increasing supply of tryptophan leads to an increase in indole accumulation, it does not improve indican productivity, suggesting that P450 activity limits overall productivity. Co-expression of different redox partners also does not improve productivity, indicating that supply of reducing power is not a bottleneck. Finally, in vitro kinetic measurements showed that the different redox partners were efficiently reduced by photosystem I but plant ferredoxin provided the highest light-dependent P450 activity. This study demonstrates the inherent ability of photosynthesis to support P450-dependent metabolic pathways. Plants and photosynthetic microbes are therefore uniquely suited for engineering P450-dependent metabolic pathways regardless of enzyme origin. Our findings have implications for metabolic engineering in photosynthetic hosts for production of high-value chemicals or drug metabolites for pharmacological studies.
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Affiliation(s)
- Silas B. Mellor
- Section for Plant Biochemistry, Department of Plant and Environmental Science, University of Copenhagen, Frederiksberg, Denmark
| | - James B. Y. H. Behrendorff
- School of Biology and Environmental Science, Queensland University of Technology, Brisbane, QLD, Australia
- Australian Research Council (ARC) Centre of Excellence in Synthetic Biology, Queensland University of Technology, Brisbane, QLD, Australia
| | - Johan Ø. Ipsen
- Section for Forest, Nature and Biomass, Department of Geosciences and Natural Resource Management, University of Copenhagen, Frederiksberg, Denmark
| | - Christoph Crocoll
- DynaMo Center, Section for Molecular Plant Biology, Department of Plant and Environmental Science, University of Copenhagen, Frederiksberg, Denmark
| | - Tomas Laursen
- Section for Plant Biochemistry, Department of Plant and Environmental Science, University of Copenhagen, Frederiksberg, Denmark
| | - Elizabeth M. J. Gillam
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, QLD, Australia
| | - Mathias Pribil
- Section for Molecular Plant Biology, Department of Plant and Environmental Science, University of Copenhagen, Frederiksberg, Denmark
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13
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Liu S, Chen Y, Du T, Zhao W, Liu X, Zhang H, Yuan Q, Gao L, Dong Y, Gao X, Gong Y, Cao P. A dimer-monomer transition captured by the crystal structures of cyanobacterial apo flavodoxin. Biochem Biophys Res Commun 2023; 639:134-141. [PMID: 36493556 DOI: 10.1016/j.bbrc.2022.11.089] [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: 11/18/2022] [Accepted: 11/27/2022] [Indexed: 11/30/2022]
Abstract
In cyanobacteria and algae (but not plants), flavodoxin (Fld) replaces ferredoxin (Fd) under stress conditions to transfer electrons from photosystem I (PSI) to ferredoxin-NADP+ reductase (FNR) during photosynthesis. Fld constitutes a small electron carrier noncovalently bound to flavin mononucleotide (FMN), and also an ideal model for revealing the protein/flavin-binding mechanism because of its relative simplicity compared to other flavoproteins. Here, we report two crystal structures of apo-Fld from Synechococcus sp. PCC 7942, one dimeric structure of 2.09 Å and one monomeric structure of 1.84 Å resolution. Analytical ultracentrifugation showed that in solution, apo-Fld exists both as monomers and dimers. Our dimer structure contains two ligand-binding pockets separated by a distance of 45 Å, much longer than the previous structures of FMN-bound dimers. These results suggested a potential dimer-monomer transition mechanism of cyanobacterial apo-Fld. We further propose that the dimer represents the "standby" state to stabilize itself, while the monomer constitutes the "ready" state to bind FMN. Furthermore, we generated a new docking model of cyanobacterial Fld-FNR complex based on the recently reported cryo-EM structures, and mapped the special interactions between Fld and FNR in detail.
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Affiliation(s)
- Shuwen Liu
- Faculty of Environment and Life, Beijing University of Technology, 100 Pingleyuan, Chaoyang District, Beijing, 100124, China
| | - Yuanyuan Chen
- The Research Platform for Protein Sciences, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Chaoyang District, Beijing, 100101, China
| | - Tianming Du
- Faculty of Environment and Life, Beijing University of Technology, 100 Pingleyuan, Chaoyang District, Beijing, 100124, China
| | - Wencong Zhao
- Faculty of Environment and Life, Beijing University of Technology, 100 Pingleyuan, Chaoyang District, Beijing, 100124, China
| | - Xuejing Liu
- Faculty of Environment and Life, Beijing University of Technology, 100 Pingleyuan, Chaoyang District, Beijing, 100124, China
| | - Heng Zhang
- Center for Multidisciplinary Research, Institute of High Energy Physics, Chinese Academy of Sciences, 19B YuquanLu, Shijingshan District, Beijing, 100049, China
| | - Qing Yuan
- Faculty of Environment and Life, Beijing University of Technology, 100 Pingleyuan, Chaoyang District, Beijing, 100124, China
| | - Liang Gao
- Faculty of Environment and Life, Beijing University of Technology, 100 Pingleyuan, Chaoyang District, Beijing, 100124, China
| | - Yuhui Dong
- Center for Multidisciplinary Research, Institute of High Energy Physics, Chinese Academy of Sciences, 19B YuquanLu, Shijingshan District, Beijing, 100049, China
| | - Xueyun Gao
- Faculty of Environment and Life, Beijing University of Technology, 100 Pingleyuan, Chaoyang District, Beijing, 100124, China.
| | - Yong Gong
- Center for Multidisciplinary Research, Institute of High Energy Physics, Chinese Academy of Sciences, 19B YuquanLu, Shijingshan District, Beijing, 100049, China.
| | - Peng Cao
- Faculty of Environment and Life, Beijing University of Technology, 100 Pingleyuan, Chaoyang District, Beijing, 100124, China.
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14
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Zhang S, Zou B, Cao P, Su X, Xie F, Pan X, Li M. Structural insights into photosynthetic cyclic electron transport. MOLECULAR PLANT 2023; 16:187-205. [PMID: 36540023 DOI: 10.1016/j.molp.2022.12.014] [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: 11/01/2022] [Revised: 12/17/2022] [Accepted: 12/18/2022] [Indexed: 06/17/2023]
Abstract
During photosynthesis, light energy is utilized to drive sophisticated biochemical chains of electron transfers, converting solar energy into chemical energy that feeds most life on earth. Cyclic electron transfer/flow (CET/CEF) plays an essential role in efficient photosynthesis, as it balances the ATP/NADPH ratio required in various regulatory and metabolic pathways. Photosystem I, cytochrome b6f, and NADH dehydrogenase (NDH) are large multisubunit protein complexes embedded in the thylakoid membrane of the chloroplast and key players in NDH-dependent CEF pathway. Furthermore, small mobile electron carriers serve as shuttles for electrons between these membrane protein complexes. Efficient electron transfer requires transient interactions between these electron donors and acceptors. Structural biology has been a powerful tool to advance our knowledge of this important biological process. A number of structures of the membrane-embedded complexes, soluble electron carrier proteins, and transient complexes composed of both have now been determined. These structural data reveal detailed interacting patterns of these electron donor-acceptor pairs, thus allowing us to visualize the different parts of the electron transfer process. This review summarizes the current state of structural knowledge of three membrane complexes and their interaction patterns with mobile electron carrier proteins.
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Affiliation(s)
- Shumeng Zhang
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Baohua Zou
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Beijing, China
| | - Peng Cao
- Faculty of Environment and Life, Beijing University of Technology, Beijing, China
| | - Xiaodong Su
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Beijing, China
| | - Fen Xie
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Beijing, China
| | - Xiaowei Pan
- College of Life Science, Capital Normal University, Beijing, China
| | - Mei Li
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.
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15
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Schulz V, Freibert SA, Boss L, Mühlenhoff U, Stehling O, Lill R. Mitochondrial [2Fe-2S] ferredoxins: new functions for old dogs. FEBS Lett 2023; 597:102-121. [PMID: 36443530 DOI: 10.1002/1873-3468.14546] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 11/23/2022] [Accepted: 11/23/2022] [Indexed: 12/02/2022]
Abstract
Ferredoxins (FDXs) comprise a large family of iron-sulfur proteins that shuttle electrons from NADPH and FDX reductases into diverse biological processes. This review focuses on the structure, function and specificity of mitochondrial [2Fe-2S] FDXs that are related to bacterial FDXs due to their endosymbiotic inheritance. Their classical function in cytochrome P450-dependent steroid transformations was identified around 1960, and is exemplified by mammalian FDX1 (aka adrenodoxin). Thirty years later the essential function in cellular Fe/S protein biogenesis was discovered for the yeast mitochondrial FDX Yah1 that is additionally crucial for the formation of haem a and ubiquinone CoQ6 . In mammals, Fe/S protein biogenesis is exclusively performed by the FDX1 paralog FDX2, despite the high structural similarity of both proteins. Recently, additional and specific roles of human FDX1 in haem a and lipoyl cofactor biosyntheses were described. For lipoyl synthesis, FDX1 transfers electrons to the radical S-adenosyl methionine-dependent lipoyl synthase to kickstart its radical chain reaction. The high target specificity of the two mammalian FDXs is contained within small conserved sequence motifs, that upon swapping change the target selection of these electron donors.
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Affiliation(s)
- Vinzent Schulz
- Institut für Zytobiologie, Philipps-Universität Marburg, Germany.,Zentrum für Synthetische Mikrobiologie Synmikro, Marburg, Germany
| | - Sven-A Freibert
- Institut für Zytobiologie, Philipps-Universität Marburg, Germany.,Zentrum für Synthetische Mikrobiologie Synmikro, Marburg, Germany
| | - Linda Boss
- Institut für Zytobiologie, Philipps-Universität Marburg, Germany.,Zentrum für Synthetische Mikrobiologie Synmikro, Marburg, Germany
| | - Ulrich Mühlenhoff
- Institut für Zytobiologie, Philipps-Universität Marburg, Germany.,Zentrum für Synthetische Mikrobiologie Synmikro, Marburg, Germany
| | - Oliver Stehling
- Institut für Zytobiologie, Philipps-Universität Marburg, Germany.,Zentrum für Synthetische Mikrobiologie Synmikro, Marburg, Germany
| | - Roland Lill
- Institut für Zytobiologie, Philipps-Universität Marburg, Germany.,Zentrum für Synthetische Mikrobiologie Synmikro, Marburg, Germany
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16
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Shahbazi M, Tohidfar M, Aliniaeifard S, Yazdanpanah F, Bosacchi M. Transgenic tobacco co-expressing flavodoxin and betaine aldehyde dehydrogenase confers cadmium tolerance through boosting antioxidant capacity. PROTOPLASMA 2022; 259:965-979. [PMID: 34686944 DOI: 10.1007/s00709-021-01714-1] [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: 07/22/2021] [Accepted: 09/29/2021] [Indexed: 06/13/2023]
Abstract
Excessive heavy metal (HM) levels in soil have become a source of concern due to their adverse effects on human health and the agriculture industry. Soil contamination by HMs leads to an accumulation of reactive oxygen species (ROSs) within the plant cell and disruption of photosynthesis-related proteins. The response of tobacco lines overexpressing flavodoxin (Fld) and betaine aldehyde dehydrogenase (BADH) to cadmium (Cd) toxicity was investigated in this study. PCR results demonstrated the expected amplicon length of each gene in the transgenic lines. Absolute qRT-PCR demonstrates a single copy of T-DNA integration into each transgenic line. Relative qRT-PCR confirmed overexpression of Fld and BADH in transgenic lines. The maximum quantum yield of photosystem II (Fv/Fm) was measured under Cd toxicity stress and revealed that transgenic lines had a higher Fv/Fm than wild-type (WT) plants. Accumulation of proline, glycine betaine (GB), and higher activity of antioxidant enzymes alongside lower levels of malondialdehyde (MDA) and hydrogen peroxide (H2O2) was indicative of a robust antioxidant system in transgenic plants. Therefore, performing a loop in reducing the ROS produced in the photosynthesis electron transport chain and stimulating the ROS scavenger enzyme activity improved the plant tolerance to Cd stress.
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Affiliation(s)
- Mehrdad Shahbazi
- Faculty of Life Sciences and Biotechnology, Shahid Beheshti University, 1983969411, Tehran, Iran
| | - Masoud Tohidfar
- Faculty of Life Sciences and Biotechnology, Shahid Beheshti University, 1983969411, Tehran, Iran.
| | - Sasan Aliniaeifard
- Photosynthesis Laboratory, Department of Horticulture, Aburaihan Campus, University of Tehran, 1417935840, Tehran, Iran
| | - Farzaneh Yazdanpanah
- Faculty of Life Sciences and Biotechnology, Shahid Beheshti University, 1983969411, Tehran, Iran
| | - Massimo Bosacchi
- Park at the, Danforth Plant Science Center, KWS Gateway Research Center, LLC, BRDG, Saint Louis, MO, USA
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17
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Arce RC, Carrillo N, Pierella Karlusich JJ. The chloroplast redox-responsive transcriptome of solanaceous plants reveals significant nuclear gene regulatory motifs associated to stress acclimation. PLANT MOLECULAR BIOLOGY 2022; 108:513-530. [PMID: 35044587 DOI: 10.1007/s11103-022-01240-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Accepted: 01/06/2022] [Indexed: 06/14/2023]
Abstract
Transcriptomes of solanaceous plants expressing a plastid-targeted antioxidant protein were analysed to identify chloroplast redox networks modulating the expression of nuclear genes associated with stress acclimation. Plastid functions depend on the coordinated expression of nuclear genes, many of them associated to developmental and stress response pathways. Plastid-generated signals mediate this coordination via retrograde signaling, which includes sensing of chloroplast redox state and levels of reactive oxygen species (ROS), although it remains a poorly understood process. Chloroplast redox poise and ROS build-up can be modified by recombinant expression of a plastid-targeted antioxidant protein, i.e., cyanobacterial flavodoxin, with the resulting plants displaying increased tolerance to multiple environmental challenges. Here we analysed the transcriptomes of these flavodoxin-expressing plants to study the coordinated transcriptional responses of the nucleus to the chloroplast redox status and ROS levels during normal growth and stress responses (drought or biotic stress) in tobacco and potato, members of the economically important Solanaceae family. We compared their transcriptomes against those from stressed and mutant plants accumulating ROS in different subcellular compartments and found distinct ROS-related imprints modulated by flavodoxin expression and/or stress. By introducing our datasets in a large-scale interaction network, we identified transcriptional factors related to ROS and stress responses potentially involved in flavodoxin-associated signaling. Finally, we discovered identical cis elements in the promoters of many genes that respond to flavodoxin in the same direction as in wild-type plants under stress, suggesting a priming effect of flavodoxin before stress manifestation. The results provide a genome-wide picture illustrating the relevance of chloroplast redox status on biotic and abiotic stress responses and suggest new cis and trans targets to generate stress-tolerant solanaceous crops.
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Affiliation(s)
- Rocío C Arce
- Instituto de Biología Molecular y Celular de Rosario (IBR-UNR/CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario (UNR), 2000, Rosario, Argentina
| | - Néstor Carrillo
- Instituto de Biología Molecular y Celular de Rosario (IBR-UNR/CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario (UNR), 2000, Rosario, Argentina
| | - Juan J Pierella Karlusich
- Ecole Normale Supérieure, PSL Research University, Institut de Biologie de l'Ecole Normale Supérieure (IBENS), CNRS UMR 8197, INSERM U1024, 46 rue d'Ulm, 75005, Paris, France.
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18
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Walter J, Kromdijk J. Here comes the sun: How optimization of photosynthetic light reactions can boost crop yields. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2022; 64:564-591. [PMID: 34962073 PMCID: PMC9302994 DOI: 10.1111/jipb.13206] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 12/22/2021] [Indexed: 05/22/2023]
Abstract
Photosynthesis started to evolve some 3.5 billion years ago CO2 is the substrate for photosynthesis and in the past 200-250 years, atmospheric levels have approximately doubled due to human industrial activities. However, this time span is not sufficient for adaptation mechanisms of photosynthesis to be evolutionarily manifested. Steep increases in human population, shortage of arable land and food, and climate change call for actions, now. Thanks to substantial research efforts and advances in the last century, basic knowledge of photosynthetic and primary metabolic processes can now be translated into strategies to optimize photosynthesis to its full potential in order to improve crop yields and food supply for the future. Many different approaches have been proposed in recent years, some of which have already proven successful in different crop species. Here, we summarize recent advances on modifications of the complex network of photosynthetic light reactions. These are the starting point of all biomass production and supply the energy equivalents necessary for downstream processes as well as the oxygen we breathe.
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Affiliation(s)
- Julia Walter
- Department of Plant SciencesUniversity of CambridgeCambridgeCB2 3EAUK
| | - Johannes Kromdijk
- Department of Plant SciencesUniversity of CambridgeCambridgeCB2 3EAUK
- Carl R Woese Institute for Genomic BiologyUniversity of Illinois Urbana‐ChampaignUrbanaIllinois61801USA
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19
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Zhou J, Hong SH. Establishing Efficient Bisphenol A Degradation by Engineering Shewanella oneidensis. Ind Eng Chem Res 2021. [DOI: 10.1021/acs.iecr.1c03324] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jiacheng Zhou
- Department of Chemical and Biological Engineering, Illinois Institute of Technology, Chicago, Illinois 60616, United States
| | - Seok Hoon Hong
- Department of Chemical and Biological Engineering, Illinois Institute of Technology, Chicago, Illinois 60616, United States
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20
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Nazari M, Tohidfar M, Ramshini H, Vahdati K. Molecular and morphological evaluation of transgenic Persian walnut plants harboring Fld gene under osmotic stress condition. Mol Biol Rep 2021; 49:433-441. [PMID: 34743274 DOI: 10.1007/s11033-021-06893-x] [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: 08/03/2021] [Accepted: 10/28/2021] [Indexed: 11/30/2022]
Abstract
BACKGROUND Soil drought stress is a limiting factor of productivity in walnut (Juglans regia L). Ferredoxin (Fd) level decreases under adverse environmental stress. Functional replacement of decreased Fd by Fld (Flavodoxin) had been shown to have protective effect under abiotic stress condition. This study aimed to evaluate four transgenic lines (L3, L4, L13 and L17) along with non-transgenic line under three osmotic stresses levels (0, 10 and 12% PEG). METHODS AND RESULTS This experiment carried out based on a completely randomized design with four replications. To confirm that the Fld gene is successfully integrated into the walnut genome, PCR and dot blot analysis were carried out. The transgenic lines of walnut expressing Fld displayed increased tolerance to osmotic stress at 10 and 12% PEG condition. Lines expressing Fld exhibited increasing tolerance to drought stress and maintained health of plants under osmotic conditions. Results of real time PCR showed that expression level of Fld gene in L4 was higher than the others. Among transgenic lines, L4 was more tolerant than other lines under osmotic stress. CONCLUSIONS These findings indicate that expression of Fld gene can increase tolerance to osmotic stress in Persian walnut and is useful tool for walnut production in arid and semi-arid regions.
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Affiliation(s)
- Mansoureh Nazari
- Department of Horticulture, College of Aburaihan, University of Tehran, Tehran, Iran
| | - Masoud Tohidfar
- Department of Plant Biotechnology, Faculty of Science and Biotechnology, Shahid Beheshti University, Tehran, Iran
| | - Hossein Ramshini
- Department of Agronomy and Plant Breeding Sciences, College of Aburaihan, University of Tehran, Tehran, Iran
| | - Kourosh Vahdati
- Department of Horticulture, College of Aburaihan, University of Tehran, Tehran, Iran.
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21
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Castell C, Rodríguez-Lumbreras LA, Hervás M, Fernández-Recio J, Navarro JA. New Insights into the Evolution of the Electron Transfer from Cytochrome f to Photosystem I in the Green and Red Branches of Photosynthetic Eukaryotes. PLANT & CELL PHYSIOLOGY 2021; 62:1082-1093. [PMID: 33772595 PMCID: PMC8557733 DOI: 10.1093/pcp/pcab044] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Accepted: 03/15/2021] [Indexed: 05/11/2023]
Abstract
In cyanobacteria and most green algae of the eukaryotic green lineage, the copper-protein plastocyanin (Pc) alternatively replaces the heme-protein cytochrome c6 (Cc6) as the soluble electron carrier from cytochrome f (Cf) to photosystem I (PSI). The functional and structural equivalence of 'green' Pc and Cc6 has been well established, representing an example of convergent evolution of two unrelated proteins. However, plants only produce Pc, despite having evolved from green algae. On the other hand, Cc6 is the only soluble donor available in most species of the red lineage of photosynthetic organisms, which includes, among others, red algae and diatoms. Interestingly, Pc genes have been identified in oceanic diatoms, probably acquired by horizontal gene transfer from green algae. However, the mechanisms that regulate the expression of a functional Pc in diatoms are still unclear. In the green eukaryotic lineage, the transfer of electrons from Cf to PSI has been characterized in depth. The conclusion is that in the green lineage, this process involves strong electrostatic interactions between partners, which ensure a high affinity and an efficient electron transfer (ET) at the cost of limiting the turnover of the process. In the red lineage, recent kinetic and structural modeling data suggest a different strategy, based on weaker electrostatic interactions between partners, with lower affinity and less efficient ET, but favoring instead the protein exchange and the turnover of the process. Finally, in diatoms the interaction of the acquired green-type Pc with both Cf and PSI may not yet be optimized.
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Affiliation(s)
- Carmen Castell
- Instituto de Bioquímica Vegetal y Fotosíntesis, CSIC and Universidad de Sevilla, cicCartuja, Sevilla, Spain
| | - Luis A Rodríguez-Lumbreras
- Instituto de Ciencias de la Vid y del Vino (ICVV), CSIC—Universidad de La Rioja—Gobierno de La Rioja, Logroño, Spain
| | - Manuel Hervás
- Instituto de Bioquímica Vegetal y Fotosíntesis, CSIC and Universidad de Sevilla, cicCartuja, Sevilla, Spain
| | - Juan Fernández-Recio
- Instituto de Ciencias de la Vid y del Vino (ICVV), CSIC—Universidad de La Rioja—Gobierno de La Rioja, Logroño, Spain
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22
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Lodeyro AF, Krapp AR, Carrillo N. Photosynthesis and chloroplast redox signaling in the age of global warming: stress tolerance, acclimation, and developmental plasticity. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:5919-5937. [PMID: 34111246 DOI: 10.1093/jxb/erab270] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Accepted: 06/07/2021] [Indexed: 06/12/2023]
Abstract
Contemporary climate change is characterized by the increased intensity and frequency of environmental stress events such as floods, droughts, and heatwaves, which have a debilitating impact on photosynthesis and growth, compromising the production of food, feed, and biofuels for an expanding population. The need to increase crop productivity in the context of global warming has fueled attempts to improve several key plant features such as photosynthetic performance, assimilate partitioning, and tolerance to environmental stresses. Chloroplast redox metabolism, including photosynthetic electron transport and CO2 reductive assimilation, are primary targets of most stress conditions, leading to excessive excitation pressure, photodamage, and propagation of reactive oxygen species. Alterations in chloroplast redox poise, in turn, provide signals that exit the plastid and modulate plant responses to the environmental conditions. Understanding the molecular mechanisms involved in these processes could provide novel tools to increase crop yield in suboptimal environments. We describe herein various interventions into chloroplast redox networks that resulted in increased tolerance to multiple sources of environmental stress. They included manipulation of endogenous components and introduction of electron carriers from other organisms, which affected not only stress endurance but also leaf size and longevity. The resulting scenario indicates that chloroplast redox pathways have an important impact on plant growth, development, and defense that goes beyond their roles in primary metabolism. Manipulation of these processes provides additional strategies for the design of crops with improved performance under destabilized climate conditions as foreseen for the future.
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Affiliation(s)
- Anabella F Lodeyro
- Instituto de Biología Molecular y Celular de Rosario (IBR-UNR/CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario (UNR), Rosario, Argentina
| | - Adriana R Krapp
- Instituto de Biología Molecular y Celular de Rosario (IBR-UNR/CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario (UNR), Rosario, Argentina
| | - Néstor Carrillo
- Instituto de Biología Molecular y Celular de Rosario (IBR-UNR/CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario (UNR), Rosario, Argentina
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Engineering Climate-Change-Resilient Crops: New Tools and Approaches. Int J Mol Sci 2021; 22:ijms22157877. [PMID: 34360645 PMCID: PMC8346029 DOI: 10.3390/ijms22157877] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 07/18/2021] [Accepted: 07/20/2021] [Indexed: 11/17/2022] Open
Abstract
Environmental adversities, particularly drought and nutrient limitation, are among the major causes of crop losses worldwide. Due to the rapid increase of the world's population, there is an urgent need to combine knowledge of plant science with innovative applications in agriculture to protect plant growth and thus enhance crop yield. In recent decades, engineering strategies have been successfully developed with the aim to improve growth and stress tolerance in plants. Most strategies applied so far have relied on transgenic approaches and/or chemical treatments. However, to cope with rapid climate change and the need to secure sustainable agriculture and biomass production, innovative approaches need to be developed to effectively meet these challenges and demands. In this review, we summarize recent and advanced strategies that involve the use of plant-related cyanobacterial proteins, macro- and micronutrient management, nutrient-coated nanoparticles, and phytopathogenic organisms, all of which offer promise as protective resources to shield plants from climate challenges and to boost stress tolerance in crops.
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Imran. The bioavailability of phosphorus in composite vs. hybrid maize differ with phosphorus and boron fertilization. PHOSPHORUS SULFUR 2021. [DOI: 10.1080/10426507.2021.1920588] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Imran
- Department of Agronomy, The University of Agriculture, Peshawar, Pakistan
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25
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Niazian M, Sadat-Noori SA, Tohidfar M, Mortazavian SMM, Sabbatini P. Betaine Aldehyde Dehydrogenase ( BADH) vs. Flavodoxin ( Fld): Two Important Genes for Enhancing Plants Stress Tolerance and Productivity. FRONTIERS IN PLANT SCIENCE 2021; 12:650215. [PMID: 33868350 PMCID: PMC8047405 DOI: 10.3389/fpls.2021.650215] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Accepted: 03/03/2021] [Indexed: 05/20/2023]
Abstract
Abiotic stresses, mainly salinity and drought, are the most important environmental threats that constrain worldwide food security by hampering plant growth and productivity. Plants cope with the adverse effects of these stresses by implementing a series of morpho-physio-biochemical adaptation mechanisms. Accumulating effective osmo-protectants, such as proline and glycine betaine (GB), is one of the important plant stress tolerance strategies. These osmolytes can trigger plant stress tolerance mechanisms, which include stress signal transduction, activating resistance genes, increasing levels of enzymatic and non-enzymatic antioxidants, protecting cell osmotic pressure, enhancing cell membrane integrity, as well as protecting their photosynthetic apparatus, especially the photosystem II (PSII) complex. Genetic engineering, as one of the most important plant biotechnology methods, helps to expedite the development of stress-tolerant plants by introducing the key tolerance genes involved in the biosynthetic pathways of osmolytes into plants. Betaine aldehyde dehydrogenase (BADH) is one of the important genes involved in the biosynthetic pathway of GB, and its introduction has led to an increased tolerance to a variety of abiotic stresses in different plant species. Replacing down-regulated ferredoxin at the acceptor side of photosystem I (PSI) with its isofunctional counterpart electron carrier (flavodoxin) is another applicable strategy to strengthen the photosynthetic apparatus of plants under stressful conditions. Heterologous expression of microbially-sourced flavodoxin (Fld) in higher plants compensates for the deficiency of ferredoxin expression and enhances their stress tolerance. BADH and Fld are multifunctional transgenes that increase the stress tolerance of different plant species and maintain their production under stressful situations by protecting and enhancing their photosynthetic apparatus. In addition to increasing stress tolerance, both BADH and Fld genes can improve the productivity, symbiotic performance, and longevity of plants. Because of the multigenic and complex nature of abiotic stresses, the concomitant delivery of BADH and Fld transgenes can lead to more satisfying results in desired plants, as these two genes enhance plant stress tolerance through different mechanisms, and their cumulative effect can be much more beneficial than their individual ones. The importance of BADH and Fld genes in enhancing plant productivity under stress conditions has been discussed in detail in the present review.
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Affiliation(s)
- Mohsen Niazian
- Field and Horticultural Crops Research Department, Kurdistan Agricultural and Natural Resources Research and Education Center, Agricultural Research, Education and Extension Organization (AREEO), Sanandaj, Iran
| | - Seyed Ahmad Sadat-Noori
- Department of Agronomy and Plant Breeding Science, College of Aburaihan, University of Tehran, Tehran, Iran
| | - Masoud Tohidfar
- Department of Plant Biotechnology, Faculty of Sciences & Biotechnology, Shahid Beheshti University, G.C., Tehran, Iran
| | | | - Paolo Sabbatini
- Department of Horticulture, Michigan State University, East Lansing, MI, United States
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26
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Varner TA, Mohamed-Raseek N, Miller AF. Assignments of 19F NMR resonances and exploration of dynamics in a long-chain flavodoxin. Arch Biochem Biophys 2021; 703:108839. [PMID: 33727041 DOI: 10.1016/j.abb.2021.108839] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 03/04/2021] [Accepted: 03/09/2021] [Indexed: 12/23/2022]
Abstract
Flavodoxin is a small protein that employs a non-covalently bound flavin to mediate single-electron transfer at low potentials. The long-chain flavodoxins possess a long surface loop that is proposed to interact with partner proteins. We have incorporated 19F-labeled tyrosine in long-chain flavodoxin from Rhodopseudomonas palustris to gain a probe of possible loop dynamics, exploiting the presence of a Tyr in the long loop in addition to Tyr residues near the flavin. We report 19F resonance assignments for all four Tyrs, and demonstration of a pair of resonances in slow exchange, both corresponding to a Tyr adjacent to the flavin. We also provide evidence for dynamics affecting the Tyr in the long loop. Thus, we show that 19F NMR of 19F-Tyr labeled flavodoxin holds promise for monitoring possible changes in conformation upon binding to partner proteins.
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Affiliation(s)
- Taylor A Varner
- Department of Chemistry, University of Kentucky, Lexington, KY, 40506, USA
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27
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Agius JE, Phalen DN, Rose K, Eden JS. Genomic Insights Into the Pathogenicity of a Novel Biofilm-Forming Enterococcus sp. Bacteria ( Enterococcus lacertideformus) Identified in Reptiles. Front Microbiol 2021; 12:635208. [PMID: 33737921 PMCID: PMC7960928 DOI: 10.3389/fmicb.2021.635208] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 02/09/2021] [Indexed: 11/23/2022] Open
Abstract
Whole genome analysis of a novel species of enterococci, Enterococcus lacertideformus, causing multi-systemic and invariably fatal disease in critically endangered Christmas Island reptiles was undertaken to determine the genetic elements and potential mechanisms conferring its pathogenic nature, biofilm-forming capabilities, immune recognition avoidance, and inability to grow in vitro. Comparative genomic analyses with related and clinically significant enterococci were further undertaken to infer the evolutionary history of the bacterium and identify genes both novel and absent. The genome had a G + C content of 35.1%, consisted of a circular chromosome, no plasmids, and was 2,419,934 bp in length (2,321 genes, 47 tRNAs, and 13 rRNAs). Multi-locus sequence typing (MLST), and single nucleotide polymorphism (SNP) analysis of multiple E. lacertideformus samples revealed they were effectively indistinguishable from one another and highly clonal. E. lacertideformus was found to be located within the Enterococcus faecium species clade and was closely related to Enterococcus villorum F1129D based on 16S rDNA and MLST house-keeping gene analysis. Antimicrobial resistance (DfreE, EfrB, tetM, bcrRABD, and sat4) and virulence genes (Fss3 and ClpP), and genes conferring tolerance to metals and biocides (n = 9) were identified. The detection of relatively few genes encoding antimicrobial resistance and virulence indicates that this bacterium may have had no exposure to recently developed and clinically significant antibiotics. Genes potentially imparting beneficial functional properties were identified, including prophages, insertion elements, integrative conjugative elements, and genomic islands. Functional CRISPR-Cas arrays, and a defective prophage region were identified in the genome. The study also revealed many genomic loci unique to E. lacertideformus which contained genes enriched in cell wall/membrane/envelop biogenesis, and carbohydrate metabolism and transport functionality. This finding and the detection of putative enterococcal biofilm determinants (EfaAfs, srtC, and scm) may underpin the novel biofilm phenotype observed for this bacterium. Comparative analysis of E. lacertideformus with phylogenetically related and clinically significant enterococci (E. villorum F1129D, Enterococcus hirae R17, E. faecium AUS0085, and Enterococcus faecalis OG1RF) revealed an absence of genes (n = 54) in E. lacertideformus, that encode metabolic functionality, which potentially hinders nutrient acquisition and/or utilization by the bacterium and precludes growth in vitro. These data provide genetic insights into the previously determined phenotype and pathogenic nature of the bacterium.
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Affiliation(s)
- Jessica Esther Agius
- Faculty of Science, Sydney School of Veterinary Science, University of Sydney, Camden, NSW, Australia
| | - David Norton Phalen
- Faculty of Science, Sydney School of Veterinary Science, University of Sydney, Camden, NSW, Australia.,Schubot Exotic Bird Health Center, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, TX, United States
| | - Karrie Rose
- Australian Registry of Wildlife Health, Taronga Conservation Society Australia, Mosman, NSW, Australia
| | - John-Sebastian Eden
- Centre for Virus Research, The Westmead Institute for Medical Research, Westmead, NSW, Australia.,Marie Bashir Institute for Infectious Diseases and Biosecurity, Faculty of Medicine and Health, Sydney School of Medicine, University of Sydney, Camperdown, NSW, Australia
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28
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Kotabova E, Malych R, Pierella Karlusich JJ, Kazamia E, Eichner M, Mach J, Lesuisse E, Bowler C, Prášil O, Sutak R. Complex Response of the Chlorarachniophyte Bigelowiella natans to Iron Availability. mSystems 2021; 6:e00738-20. [PMID: 33563784 PMCID: PMC7883536 DOI: 10.1128/msystems.00738-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Accepted: 01/10/2021] [Indexed: 11/20/2022] Open
Abstract
The productivity of the ocean is largely dependent on iron availability, and marine phytoplankton have evolved sophisticated mechanisms to cope with chronically low iron levels in vast regions of the open ocean. By analyzing the metabarcoding data generated from the Tara Oceans expedition, we determined how the global distribution of the model marine chlorarachniophyte Bigelowiella natans varies across regions with different iron concentrations. We performed a comprehensive proteomics analysis of the molecular mechanisms underpinning the adaptation of B. natans to iron scarcity and report on the temporal response of cells to iron enrichment. Our results highlight the role of phytotransferrin in iron homeostasis and indicate the involvement of CREG1 protein in the response to iron availability. Analysis of the Tara Oceans metagenomes and metatranscriptomes also points to a similar role for CREG1, which is found to be widely distributed among marine plankton but to show a strong bias in gene and transcript abundance toward iron-deficient regions. Our analyses allowed us to define a new subfamily of the CobW domain-containing COG0523 putative metal chaperones which are involved in iron metabolism and are restricted to only a few phytoplankton lineages in addition to B. natans At the physiological level, we elucidated the mechanisms allowing a fast recovery of PSII photochemistry after resupply of iron. Collectively, our study demonstrates that B. natans is well adapted to dynamically respond to a changing iron environment and suggests that CREG1 and COG0523 are important components of iron homeostasis in B. natans and other phytoplankton.IMPORTANCE Despite low iron availability in the ocean, marine phytoplankton require considerable amounts of iron for their growth and proliferation. While there is a constantly growing knowledge of iron uptake and its role in the cellular processes of the most abundant marine photosynthetic groups, there are still largely overlooked branches of the eukaryotic tree of life, such as the chlorarachniophytes. In the present work, we focused on the model chlorarachniophyte Bigelowiella natans, integrating physiological and proteomic analyses in culture conditions with the mining of omics data generated by the Tara Oceans expedition. We provide unique insight into the complex responses of B. natans to iron availability, including novel links to iron metabolism conserved in other phytoplankton lineages.
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Affiliation(s)
- Eva Kotabova
- Institute of Microbiology, Academy of Sciences, Centrum Algatech, Trebon, Czech Republic
| | - Ronald Malych
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Vestec, Czech Republic
| | - Juan José Pierella Karlusich
- Institut de Biologie de l'ENS, Département de Biologie, École Normale Supérieure, CNRS, INSERM, Université PSL, Paris, France
- CNRS Research Federation for the Study of Global Ocean Systems Ecology and Evolution, FR2022/Tara Oceans GOSEE, Paris, France
| | - Elena Kazamia
- Institut de Biologie de l'ENS, Département de Biologie, École Normale Supérieure, CNRS, INSERM, Université PSL, Paris, France
| | - Meri Eichner
- Institute of Microbiology, Academy of Sciences, Centrum Algatech, Trebon, Czech Republic
| | - Jan Mach
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Vestec, Czech Republic
| | - Emmanuel Lesuisse
- Jacques Monod Institute, UMR7592 CNRS, Paris Diderot University, Paris, France
| | - Chris Bowler
- Institut de Biologie de l'ENS, Département de Biologie, École Normale Supérieure, CNRS, INSERM, Université PSL, Paris, France
- CNRS Research Federation for the Study of Global Ocean Systems Ecology and Evolution, FR2022/Tara Oceans GOSEE, Paris, France
| | - Ondřej Prášil
- Institute of Microbiology, Academy of Sciences, Centrum Algatech, Trebon, Czech Republic
| | - Robert Sutak
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Vestec, Czech Republic
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29
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Castell C, Bernal-Bayard P, Ortega JM, Roncel M, Hervás M, Navarro JA. The heterologous expression of a plastocyanin in the diatom Phaeodactylum tricornutum improves cell growth under iron-deficient conditions. PHYSIOLOGIA PLANTARUM 2021; 171:277-290. [PMID: 33247466 DOI: 10.1111/ppl.13290] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 11/18/2020] [Accepted: 11/19/2020] [Indexed: 06/12/2023]
Abstract
We have investigated if the heterologous expression of a functional green alga plastocyanin in the diatom Phaeodactylum tricornutum can improve photosynthetic activity and cell growth. Previous in vitro assays showed that a single-mutant of the plastocyanin from the green algae Chlamydomonas reinhardtii is effective in reducing P. tricornutum photosystem I. In this study, in vivo assays with P. tricornutum strains expressing this plastocyanin indicate that even the relatively low intracellular concentrations of holo-plastocyanin detected (≈4 μM) are enough to promote an increased growth (up to 60%) under iron-deficient conditions as compared with the WT strain, measured as higher cell densities, content in pigments and active photosystem I, global photosynthetic rates per cell, and even cell volume. In addition, the presence of plastocyanin as an additional photosynthetic electron carrier seems to decrease the over-reduction of the plastoquinone pool. Consequently, it promotes an improvement in the maximum quantum yield of both photosystem II and I, together with a decrease in the acceptor side photoinhibition of photosystem II-also associated to a reduced oxidative stress-a decrease in the peroxidation of membrane lipids in the choroplast, and a lower degree of limitation on the donor side of photosystem I. Thus the heterologous plastocyanin appears to act as a functional electron carrier, alternative to the native cytochrome c6 , under iron-limiting conditions.
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Affiliation(s)
- Carmen Castell
- Instituto de Bioquímica Vegetal y Fotosíntesis, cicCartuja, Universidad de Sevilla and CSIC, Seville, Spain
| | - Pilar Bernal-Bayard
- Instituto de Bioquímica Vegetal y Fotosíntesis, cicCartuja, Universidad de Sevilla and CSIC, Seville, Spain
| | - José M Ortega
- Instituto de Bioquímica Vegetal y Fotosíntesis, cicCartuja, Universidad de Sevilla and CSIC, Seville, Spain
| | - Mercedes Roncel
- Instituto de Bioquímica Vegetal y Fotosíntesis, cicCartuja, Universidad de Sevilla and CSIC, Seville, Spain
| | - Manuel Hervás
- Instituto de Bioquímica Vegetal y Fotosíntesis, cicCartuja, Universidad de Sevilla and CSIC, Seville, Spain
| | - José A Navarro
- Instituto de Bioquímica Vegetal y Fotosíntesis, cicCartuja, Universidad de Sevilla and CSIC, Seville, Spain
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30
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Karlusich JJP, Arce RC, Shahinnia F, Sonnewald S, Sonnewald U, Zurbriggen MD, Hajirezaei MR, Carrillo N. Transcriptional and Metabolic Profiling of Potato Plants Expressing a Plastid-Targeted Electron Shuttle Reveal Modulation of Genes Associated to Drought Tolerance by Chloroplast Redox Poise. Int J Mol Sci 2020; 21:E7199. [PMID: 33003500 PMCID: PMC7582712 DOI: 10.3390/ijms21197199] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 09/25/2020] [Accepted: 09/28/2020] [Indexed: 12/26/2022] Open
Abstract
Water limitation represents the main environmental constraint affecting crop yield worldwide. Photosynthesis is a primary drought target, resulting in over-reduction of the photosynthetic electron transport chain and increased production of reactive oxygen species in plastids. Manipulation of chloroplast electron distribution by introducing alternative electron transport sinks has been shown to increase plant tolerance to multiple environmental challenges including hydric stress, suggesting that a similar strategy could be used to improve drought tolerance in crops. We show herein that the expression of the cyanobacterial electron shuttle flavodoxin in potato chloroplasts protected photosynthetic activities even at a pre-symptomatic stage of drought. Transcriptional and metabolic profiling revealed an attenuated response to the adverse condition in flavodoxin-expressing plants, correlating with their increased stress tolerance. Interestingly, 5-6% of leaf-expressed genes were affected by flavodoxin in the absence of drought, representing pathways modulated by chloroplast redox status during normal growth. About 300 of these genes potentially contribute to stress acclimation as their modulation by flavodoxin proceeds in the same direction as their drought response in wild-type plants. Tuber yield losses under chronic water limitation were mitigated in flavodoxin-expressing plants, indicating that the flavoprotein has the potential to improve major agronomic traits in potato.
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Affiliation(s)
- Juan J. Pierella Karlusich
- Instituto de Biología Molecular y Celular de Rosario (IBR-UNR/CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario (UNR), Rosario 2000, Argentina; (J.J.P.K.); (R.C.A.)
| | - Rocío C. Arce
- Instituto de Biología Molecular y Celular de Rosario (IBR-UNR/CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario (UNR), Rosario 2000, Argentina; (J.J.P.K.); (R.C.A.)
| | - Fahimeh Shahinnia
- Leibniz Institute of Plant Genetics and Crop Plant Research, OT Gatersleben, Corrensstrasse, D-06466 Stadt Seeland, Germany;
| | - Sophia Sonnewald
- Division of Biochemistry, Department of Biology, Friedrich-Alexander-University Erlangen-Nurenberg, 91058 Erlangen, Germany; (S.S.); (U.S.)
| | - Uwe Sonnewald
- Division of Biochemistry, Department of Biology, Friedrich-Alexander-University Erlangen-Nurenberg, 91058 Erlangen, Germany; (S.S.); (U.S.)
| | - Matias D. Zurbriggen
- Institute of Synthetic Biology and CEPLAS, University of Düsseldorf, Universitätsstr, 1 40225 Düsseldorf, Germany
| | - Mohammad-Reza Hajirezaei
- Leibniz Institute of Plant Genetics and Crop Plant Research, OT Gatersleben, Corrensstrasse, D-06466 Stadt Seeland, Germany;
| | - Néstor Carrillo
- Instituto de Biología Molecular y Celular de Rosario (IBR-UNR/CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario (UNR), Rosario 2000, Argentina; (J.J.P.K.); (R.C.A.)
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Gómez R, Figueroa N, Melzer M, Hajirezaei MR, Carrillo N, Lodeyro AF. Photosynthetic characterization of flavodoxin-expressing tobacco plants reveals a high light acclimation-like phenotype. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2020; 1861:148211. [PMID: 32315624 DOI: 10.1016/j.bbabio.2020.148211] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 03/17/2020] [Accepted: 04/14/2020] [Indexed: 01/15/2023]
Abstract
Flavodoxins are electron carrier flavoproteins present in bacteria and photosynthetic microorganisms which duplicate the functional properties of iron-sulphur containing ferredoxins and replace them under adverse environmental situations that lead to ferredoxin decline. When expressed in plant chloroplasts, flavodoxin complemented ferredoxin deficiency and improved tolerance to multiple sources of biotic, abiotic and xenobiotic stress. Analysis of flavodoxin-expressing plants grown under normal conditions, in which the two carriers are present, revealed phenotypic effects unrelated to ferredoxin replacement. Flavodoxin thus provided a tool to alter the chloroplast redox poise in a customized way and to investigate its consequences on plant physiology and development. We describe herein the effects exerted by the flavoprotein on the function of the photosynthetic machinery. Pigment analysis revealed significant increases in chlorophyll a, carotenoids and chlorophyll a/b ratio in flavodoxin-expressing tobacco lines. Results suggest smaller antenna size in these plants, supported by lower relative contents of light-harvesting complex proteins. Chlorophyll a fluorescence and P700 spectroscopy measurements indicated that transgenic plants displayed higher quantum yields for both photosystems, a more oxidized plastoquinone pool under steady-state conditions and faster plastoquinone dark oxidation after a pulse of saturating light. Many of these effects resemble the phenotypes exhibited by leaves adapted to high irradiation, a most common environmental hardship faced by plants growing in the field. The results suggest that flavodoxin-expressing plants would be better prepared to cope with this adverse situation, and concur with earlier observations reporting that hundreds of stress-responsive genes were induced in the absence of stress in these lines.
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Affiliation(s)
- Rodrigo Gómez
- Instituto de Biología Molecular y Celular de Rosario (IBR-UNR/CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario (UNR), 2000 Rosario, Argentina
| | - Nicolás Figueroa
- Instituto de Biología Molecular y Celular de Rosario (IBR-UNR/CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario (UNR), 2000 Rosario, Argentina
| | - Michael Melzer
- Leibniz Institute of Plant Genetics and Crop Plant Research, OT Gatersleben, Corrensstrasse 3, D-06466 Stadt Seeland, Germany
| | - Mohammad-Reza Hajirezaei
- Leibniz Institute of Plant Genetics and Crop Plant Research, OT Gatersleben, Corrensstrasse 3, D-06466 Stadt Seeland, Germany
| | - Néstor Carrillo
- Instituto de Biología Molecular y Celular de Rosario (IBR-UNR/CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario (UNR), 2000 Rosario, Argentina
| | - Anabella F Lodeyro
- Instituto de Biología Molecular y Celular de Rosario (IBR-UNR/CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario (UNR), 2000 Rosario, Argentina.
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Kroh GE, Pilon M. Regulation of Iron Homeostasis and Use in Chloroplasts. Int J Mol Sci 2020; 21:E3395. [PMID: 32403383 PMCID: PMC7247011 DOI: 10.3390/ijms21093395] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 05/08/2020] [Accepted: 05/09/2020] [Indexed: 01/20/2023] Open
Abstract
Iron (Fe) is essential for life because of its role in protein cofactors. Photosynthesis, in particular photosynthetic electron transport, has a very high demand for Fe cofactors. Fe is commonly limiting in the environment, and therefore photosynthetic organisms must acclimate to Fe availability and avoid stress associated with Fe deficiency. In plants, adjustment of metabolism, of Fe utilization, and gene expression, is especially important in the chloroplasts during Fe limitation. In this review, we discuss Fe use, Fe transport, and mechanisms of acclimation to Fe limitation in photosynthetic lineages with a focus on the photosynthetic electron transport chain. We compare Fe homeostasis in Cyanobacteria, the evolutionary ancestors of chloroplasts, with Fe homeostasis in green algae and in land plants in order to provide a deeper understanding of how chloroplasts and photosynthesis may cope with Fe limitation.
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Affiliation(s)
| | - Marinus Pilon
- Department of Biology, Colorado State University Department of Biology, Fort Collins, CO 80523, USA;
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Structure and function of an unusual flavodoxin from the domain Archaea. Proc Natl Acad Sci U S A 2019; 116:25917-25922. [PMID: 31801875 DOI: 10.1073/pnas.1908578116] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Flavodoxins, electron transfer proteins essential for diverse metabolisms in microbes from the domain Bacteria, are extensively characterized. Remarkably, although genomic annotations of flavodoxins are widespread in microbes from the domain Archaea, none have been isolated and characterized. Herein is described the structural, biochemical, and physiological characterization of an unusual flavodoxin (FldA) from Methanosarcina acetivorans, an acetate-utilizing methane-producing microbe of the domain Archaea In contrast to all flavodoxins, FldA is homodimeric, markedly less acidic, and stabilizes an anionic semiquinone. The crystal structure reveals an flavin mononucleotide (FMN) binding site unique from all other flavodoxins that provides a rationale for stabilization of the anionic semiquinone and a remarkably low reduction potentials for both the oxidized/semiquinone (-301 mV) and semiquinone/hydroquinone couples (-464 mV). FldA is up-regulated in acetate-grown versus methanol-grown cells and shown here to substitute for ferredoxin in mediating the transfer of low potential electrons from the carbonyl of acetate to the membrane-bound electron transport chain that generates ion gradients driving ATP synthesis. FldA offers potential advantages over ferredoxin by (i) sparing iron for abundant iron-sulfur proteins essential for acetotrophic growth and (ii) resilience to oxidative damage.
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Sétif P, Boussac A, Krieger-Liszkay A. Near-infrared in vitro measurements of photosystem I cofactors and electron-transfer partners with a recently developed spectrophotometer. PHOTOSYNTHESIS RESEARCH 2019; 142:307-319. [PMID: 31482263 DOI: 10.1007/s11120-019-00665-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Accepted: 08/20/2019] [Indexed: 06/10/2023]
Abstract
A kinetic-LED-array-spectrophotometer (Klas) was recently developed for measuring in vivo redox changes of P700, plastocyanin (PCy), and ferredoxin (Fd) in the near-infrared (NIR). This spectrophotometer is used in the present work for in vitro light-induced measurements with various combinations of photosystem I (PSI) from tobacco and two different cyanobacteria, spinach plastocyanin, cyanobacterial cytochrome c6 (cyt. c6), and Fd. It is shown that cyt. c6 oxidation contributes to the NIR absorption changes. The reduction of (FAFB), the terminal electron acceptor of PSI, was also observed and the shape of the (FAFB) NIR difference spectrum is similar to that of Fd. The NIR difference spectra of the electron-transfer cofactors were compared between different organisms and to those previously measured in vivo, whereas the relative absorption coefficients of all cofactors were determined by using single PSI turnover conditions. Thus, the (840 nm minus 965 nm) extinction coefficients of the light-induced species (oxidized minus reduced for PC and cyt. c6, reduced minus oxidized for (FAFB), and Fd) were determined with values of 0.207 ± 0.004, - 0.033 ± 0.006, - 0.036 ± 0.008, and - 0.021 ± 0.005 for PCy, cyt. c6, (FAFB) (single reduction), and Fd, respectively, by taking a reference value of + 1 for P700+. The fact that the NIR P700 coefficient is larger than that of PCy and much larger than that of other contributing species, combined with the observed variability in the NIR P700 spectral shape, emphasizes that deconvolution of NIR signals into different components requires a very precise determination of the P700 spectrum.
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Affiliation(s)
- Pierre Sétif
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, 91198, Gif-Sur-Yvette Cedex, France.
| | - Alain Boussac
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, 91198, Gif-Sur-Yvette Cedex, France
| | - Anja Krieger-Liszkay
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, 91198, Gif-Sur-Yvette Cedex, France
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Mayta ML, Hajirezaei MR, Carrillo N, Lodeyro AF. Leaf Senescence: The Chloroplast Connection Comes of Age. PLANTS (BASEL, SWITZERLAND) 2019; 8:E495. [PMID: 31718069 PMCID: PMC6918220 DOI: 10.3390/plants8110495] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 11/05/2019] [Accepted: 11/06/2019] [Indexed: 12/15/2022]
Abstract
Leaf senescence is a developmental process critical for plant fitness, which involves genetically controlled cell death and ordered disassembly of macromolecules for reallocating nutrients to juvenile and reproductive organs. While natural leaf senescence is primarily associated with aging, it can also be induced by environmental and nutritional inputs including biotic and abiotic stresses, darkness, phytohormones and oxidants. Reactive oxygen species (ROS) are a common thread in stress-dependent cell death and also increase during leaf senescence. Involvement of chloroplast redox chemistry (including ROS propagation) in modulating cell death is well supported, with photosynthesis playing a crucial role in providing redox-based signals to this process. While chloroplast contribution to senescence received less attention, recent findings indicate that changes in the redox poise of these organelles strongly affect senescence timing and progress. In this review, the involvement of chloroplasts in leaf senescence execution is critically assessed in relation to available evidence and the role played by environmental and developmental cues such as stress and phytohormones. The collected results indicate that chloroplasts could cooperate with other redox sources (e.g., mitochondria) and signaling molecules to initiate the committed steps of leaf senescence for a best use of the recycled nutrients in plant reproduction.
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Affiliation(s)
- Martín L. Mayta
- Instituto de Biología Molecular y Celular de Rosario (IBR-UNR/CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario (UNR), 2000 Rosario, Argentina;
| | - Mohammad-Reza Hajirezaei
- Leibniz Institute of Plant Genetics and Crop Plant Research, OT Gatersleben, Corrensstrasse, D-06466 Stadt Seeland, Germany;
| | - Néstor Carrillo
- Instituto de Biología Molecular y Celular de Rosario (IBR-UNR/CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario (UNR), 2000 Rosario, Argentina;
| | - Anabella F. Lodeyro
- Instituto de Biología Molecular y Celular de Rosario (IBR-UNR/CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario (UNR), 2000 Rosario, Argentina;
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Bertsova YV, Kulik LV, Mamedov MD, Baykov AA, Bogachev AV. Flavodoxin with an air-stable flavin semiquinone in a green sulfur bacterium. PHOTOSYNTHESIS RESEARCH 2019; 142:127-136. [PMID: 31302833 DOI: 10.1007/s11120-019-00658-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Accepted: 07/04/2019] [Indexed: 06/10/2023]
Abstract
Flavodoxins are small proteins with a non-covalently bound FMN that can accept two electrons and accordingly adopt three redox states: oxidized (quinone), one-electron reduced (semiquinone), and two-electron reduced (quinol). In iron-deficient cyanobacteria and algae, flavodoxin can substitute for ferredoxin as the electron carrier in the photosynthetic electron transport chain. Here, we demonstrate a similar function for flavodoxin from the green sulfur bacterium Chlorobium phaeovibrioides (cp-Fld). The expression of the cp-Fld gene, found in a close proximity with the genes for other proteins associated with iron transport and storage, increased in a low-iron medium. cp-Fld produced in Escherichia coli exhibited the optical, ERP, and electron-nuclear double resonance spectra that were similar to those of known flavodoxins. However, unlike all other flavodoxins, cp-Fld exhibited unprecedented stability of FMN semiquinone to oxidation by air and difference in midpoint redox potentials for the quinone-semiquinone and semiquinone-quinol couples (- 110 and - 530 mV, respectively). cp-Fld could be reduced by pyruvate:ferredoxin oxidoreductase found in the membrane-free extract of Chl. phaeovibrioides cells and photo-reduced by the photosynthetic reaction center found in membrane vesicles from these cells. The green sulfur bacterium Chl. phaeovibrioides appears thus to be a new type of the photosynthetic organisms that can use flavodoxin as an alternative electron carrier to cope with iron deficiency.
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Affiliation(s)
- Yulia V Bertsova
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia, 119234
| | - Leonid V Kulik
- Institute of Chemical Kinetics and Combustion, Russian Academy of Sciences, Novosibirsk, Russia, 630090
- Novosibirsk State University, Novosibirsk, Russia, 630090
| | - Mahir D Mamedov
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia, 119234
| | - Alexander A Baykov
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia, 119234
| | - Alexander V Bogachev
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia, 119234.
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Wu B, Atkinson JT, Kahanda D, Bennett GN, Silberg JJ. Combinatorial design of chemical‐dependent protein switches for controlling intracellular electron transfer. AIChE J 2019. [DOI: 10.1002/aic.16796] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
- Bingyan Wu
- Biochemistry & Cell Biology Graduate Program Rice University Houston Texas
- Department of Biosciences Rice University Houston Texas
| | - Joshua T. Atkinson
- Department of Biosciences Rice University Houston Texas
- Systems, Synthetic, & Physical Biology Graduate Program Rice University Houston Texas
| | | | - George N. Bennett
- Department of Biosciences Rice University Houston Texas
- Department of Chemical & Biomolecular Engineering Rice University Houston Texas
| | - Jonathan J. Silberg
- Department of Biosciences Rice University Houston Texas
- Department of Chemical & Biomolecular Engineering Rice University Houston Texas
- Department of Bioengineering Rice University Houston Texas
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Rodríguez-Castro L, Méndez V, Durán RE, Seeger M. Long-chain flavodoxin FldX1 improves Paraburkholderia xenovorans LB400 tolerance to oxidative stress caused by paraquat and H2O2. PLoS One 2019; 14:e0221881. [PMID: 31469877 PMCID: PMC6716667 DOI: 10.1371/journal.pone.0221881] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Accepted: 08/17/2019] [Indexed: 11/26/2022] Open
Abstract
Flavodoxins are small electron transfer proteins containing flavin mononucleotide (FMN) as a prosthetic group, which play an important role during oxidative stress or iron limitation. The aims of this study were the identification and characterization of flavodoxins in the model aromatic-degrader Paraburkholderia xenovorans LB400 and the analyses of their protective effects during oxidative stress induced by paraquat and H2O2. Two genes (BxeA0278 and BxeB0391) encoding flavodoxins (hereafter referred to as fldX for flavodoxin from P. xenovorans), were identified at the LB400 major and minor chromosome. Genomic context of the flavodoxin-encoding genes showed genes encoding membrane proteins, transporters, and proteins involved in redox processes and biosynthesis of macromolecules. A secondary structure prediction of both LB400 flavodoxins showed the characteristic flavodoxin structure of five ß-sheets intercalated with five α-helices. FldX1 contains a loop intercalated in the fifth β-strand, which indicates that it belongs to the long-chain flavodoxins, whereas FldX2 is a short-chain flavodoxin. A phylogenetic analysis of 73 flavodoxins from 43 bacterial genera revealed eight clusters (I-VIII), while FldX1 and FldX2 grouped separately within a long-chain and a short-chain flavodoxin clades. FldX1 and FldX2 were overexpressed in P. xenovorans. Interestingly, the strain overexpressing the long-chain flavodoxin FldX1 (p2-fldX1) showed a faster growth in glucose than the control strain. The recombinant strain overexpressing the long-chain flavodoxin FldX1 (p2-fldx1) exposed to paraquat (20 mM) possessed lower susceptibility to growth inhibition on plates and higher survival in liquid medium than the control strain. The strains overexpressing the flavodoxins FldX1 and FldX2 showed higher survival during exposure to 1 mM paraquat (>95%) than the control strain (68%). Compared to the control strain, strains overexpressing FldX1 and FldX2 showed lower lipid peroxidation (>20%) after exposure to 1 mM paraquat and a lower protein carbonylation (~30%) after exposure to 1 mM H2O2 was observed. During exposure to paraquat, strain p2-fldx1 downregulated the katG4, hpf, trxB1 and ohr genes (> 2-fold), whereas strain p2-fldx2 upregulated the oxyR and ahpC1 genes (> 2-fold). In conclusion, the flavodoxins FldX1 and FldX2 of P. xenovorans LB400 conferred protection to cells exposed to the oxidizing agents paraquat and H2O2.
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Affiliation(s)
- Laura Rodríguez-Castro
- Laboratorio de Microbiología Molecular y Biotecnología Ambiental, Departamento de Química & Centro de Biotecnología, Universidad Técnica Federico Santa María, Valparaíso, Chile
| | - Valentina Méndez
- Laboratorio de Microbiología Molecular y Biotecnología Ambiental, Departamento de Química & Centro de Biotecnología, Universidad Técnica Federico Santa María, Valparaíso, Chile
| | - Roberto E. Durán
- Laboratorio de Microbiología Molecular y Biotecnología Ambiental, Departamento de Química & Centro de Biotecnología, Universidad Técnica Federico Santa María, Valparaíso, Chile
| | - Michael Seeger
- Laboratorio de Microbiología Molecular y Biotecnología Ambiental, Departamento de Química & Centro de Biotecnología, Universidad Técnica Federico Santa María, Valparaíso, Chile
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Gómez R, Vicino P, Carrillo N, Lodeyro AF. Manipulation of oxidative stress responses as a strategy to generate stress-tolerant crops. From damage to signaling to tolerance. Crit Rev Biotechnol 2019; 39:693-708. [PMID: 30991845 DOI: 10.1080/07388551.2019.1597829] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Plants exposed to hostile environmental conditions such as drought or extreme temperatures usually undergo oxidative stress, which has long been assumed to significantly contribute to the damage suffered by the organism. Reactive oxygen species (ROS) overproduced under stress conditions were proposed to destroy membrane lipids and to inactivate proteins and photosystems, ultimately leading to cell death. Accordingly, considerable effort has been devoted, over the years, to improve stress tolerance by strengthening antioxidant and dissipative mechanisms. Although the notion that ROS cause indiscriminate damage in vivo has been progressively replaced by the alternate concept that they act as signaling molecules directing critical plant developmental and environmental responses including cell death, the induction of genes encoding antioxidant activities is commonplace under many environmental stresses, suggesting that their manipulation still offers promise. The features and consequences of ROS effects depend on the balance between various interacting pathways including ROS synthesis and scavenging, energy dissipation, conjugative reactions, and eventually reductive repair. They represent many possibilities for genetic manipulation. We report, herein, a comprehensive survey of transgenic plants in which components of the ROS-associated pathways were overexpressed, and of the stress phenotypes displayed by the corresponding transformants. Genetic engineering of different stages of ROS metabolism such as synthesis, scavenging, and reductive repair revealed a strong correlation between down-regulation of ROS levels and increased stress tolerance in plants grown under controlled conditions. Field assays are scarce, and are eagerly required to assess the possible application of this strategy to agriculture.
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Affiliation(s)
- Rodrigo Gómez
- a Facultad de Ciencias Bioquímicas y Farmacéuticas, Biología del Estrés en Plantas, Instituto de Biología Molecular y Celular de Rosario (IBR-UNR/CONICET) , Universidad Nacional de Rosario (UNR) , Rosario , Argentina
| | - Paula Vicino
- a Facultad de Ciencias Bioquímicas y Farmacéuticas, Biología del Estrés en Plantas, Instituto de Biología Molecular y Celular de Rosario (IBR-UNR/CONICET) , Universidad Nacional de Rosario (UNR) , Rosario , Argentina
| | - Néstor Carrillo
- a Facultad de Ciencias Bioquímicas y Farmacéuticas, Biología del Estrés en Plantas, Instituto de Biología Molecular y Celular de Rosario (IBR-UNR/CONICET) , Universidad Nacional de Rosario (UNR) , Rosario , Argentina
| | - Anabella F Lodeyro
- a Facultad de Ciencias Bioquímicas y Farmacéuticas, Biología del Estrés en Plantas, Instituto de Biología Molecular y Celular de Rosario (IBR-UNR/CONICET) , Universidad Nacional de Rosario (UNR) , Rosario , Argentina
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Mayta ML, Arce RC, Zurbriggen MD, Valle EM, Hajirezaei MR, Zanor MI, Carrillo N. Expression of a Chloroplast-Targeted Cyanobacterial Flavodoxin in Tomato Plants Increases Harvest Index by Altering Plant Size and Productivity. FRONTIERS IN PLANT SCIENCE 2019; 10:1432. [PMID: 31798604 PMCID: PMC6865847 DOI: 10.3389/fpls.2019.01432] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Accepted: 10/15/2019] [Indexed: 05/02/2023]
Abstract
Tomato is the most important horticultural crop worldwide. Domestication has led to the selection of highly fruited genotypes, and the harvest index (HI), defined as the ratio of fruit yield over total plant biomass, is usually employed as a biomarker of agronomic value. Improvement of HI might then result from increased fruit production and/or lower vegetative growth. Reduction in vegetative biomass has been accomplished in various plant species by expression of flavodoxin, an electron shuttle flavoprotein that interacts with redox-based pathways of chloroplasts including photosynthesis. However, the effect of this genetic intervention on the development of reproductive organs has not been investigated. We show herein that expression of a plastid-targeted cyanobacterial flavodoxin in tomato resulted in significant reduction of plant size affecting stems, leaves, and fruit. Decreased size correlated with smaller cells and was accompanied by higher pigment contents and photosynthetic activities per leaf cross-section. Flavodoxin accumulated in green fruit but declined with ripening. Significant increases in HI were observed in flavodoxin-expressing lines due to the production of higher fruit number per plant in smaller plants. Therefore, overall yields can be enhanced by increasing plant density in the field. Metabolic profiling of ripe red fruit showed that levels of sugars, organic acids, and amino acids were similar or higher in transgenic plants, indicating that there was no trade-off between increased HI and fruit metabolite contents in flavodoxin-expressing plants. Taken together, our results show that flavodoxin has the potential to improve major agronomic traits when introduced in tomato.
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Affiliation(s)
- Martín L. Mayta
- Instituto de Biología Molecular y Celular de Rosario (IBR-UNR/CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario (UNR), Rosario, Argentina
| | - Rocío C. Arce
- Instituto de Biología Molecular y Celular de Rosario (IBR-UNR/CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario (UNR), Rosario, Argentina
| | - Matias D. Zurbriggen
- Instituto de Biología Molecular y Celular de Rosario (IBR-UNR/CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario (UNR), Rosario, Argentina
| | - Estela M. Valle
- Instituto de Biología Molecular y Celular de Rosario (IBR-UNR/CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario (UNR), Rosario, Argentina
| | | | - María I. Zanor
- Instituto de Biología Molecular y Celular de Rosario (IBR-UNR/CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario (UNR), Rosario, Argentina
- *Correspondence: María I. Zanor, ; Néstor Carrillo,
| | - Néstor Carrillo
- Instituto de Biología Molecular y Celular de Rosario (IBR-UNR/CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario (UNR), Rosario, Argentina
- *Correspondence: María I. Zanor, ; Néstor Carrillo,
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Campbell IJ, Bennett GN, Silberg JJ. Evolutionary Relationships Between Low Potential Ferredoxin and Flavodoxin Electron Carriers. FRONTIERS IN ENERGY RESEARCH 2019; 7:10.3389/fenrg.2019.00079. [PMID: 32095484 PMCID: PMC7039249 DOI: 10.3389/fenrg.2019.00079] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Proteins from the ferredoxin (Fd) and flavodoxin (Fld) families function as low potential electrical transfer hubs in cells, at times mediating electron transfer between overlapping sets of oxidoreductases. To better understand protein electron carrier (PEC) use across the domains of life, we evaluated the distribution of genes encoding [4Fe-4S] Fd, [2Fe-2S] Fd, and Fld electron carriers in over 7,000 organisms. Our analysis targeted genes encoding small PEC genes encoding proteins having ≤200 residues. We find that the average number of small PEC genes per Archaea (~13), Bacteria (~8), and Eukarya (~3) genome varies, with some organisms containing as many as 54 total PEC genes. Organisms fall into three groups, including those lacking genes encoding low potential PECs (3%), specialists with a single PEC gene type (20%), and generalists that utilize multiple PEC types (77%). Mapping PEC gene usage onto an evolutionary tree highlights the prevalence of [4Fe-4S] Fds in ancient organisms that are deeply rooted, the expansion of [2Fe-2S] Fds with the advent of photosynthesis and a concomitant decrease in [4Fe-4S] Fds, and the expansion of Flds in organisms that inhabit low-iron host environments. Surprisingly, [4Fe-4S] Fds present a similar abundance in aerobes as [2Fe-2S] Fds. This bioinformatic study highlights understudied PECs whose structure, stability, and partner specificity should be further characterized.
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Affiliation(s)
- Ian J. Campbell
- Biochemistry and Cell Biology Graduate Program, Rice University, Houston, TX, United States
| | - George N. Bennett
- Department of BioSciences, Rice University, Houston, TX, United States
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, TX, United States
| | - Jonathan J. Silberg
- Department of BioSciences, Rice University, Houston, TX, United States
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, TX, United States
- Department of Bioengineering, Rice University Houston, TX, United States
- Correspondence: Jonathan J. Silberg
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Smith-Moore CM, Grunden AM. Bacteria and archaea as the sources of traits for enhanced plant phenotypes. Biotechnol Adv 2018; 36:1900-1916. [DOI: 10.1016/j.biotechadv.2018.07.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Revised: 07/12/2018] [Accepted: 07/24/2018] [Indexed: 10/28/2022]
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Su J, Yang L, Zhu Q, Wu H, He Y, Liu Y, Xu J, Jiang D, Zhang S. Active photosynthetic inhibition mediated by MPK3/MPK6 is critical to effector-triggered immunity. PLoS Biol 2018; 16:e2004122. [PMID: 29723186 PMCID: PMC5953503 DOI: 10.1371/journal.pbio.2004122] [Citation(s) in RCA: 113] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Revised: 05/15/2018] [Accepted: 04/06/2018] [Indexed: 01/04/2023] Open
Abstract
Extensive research revealed tremendous details about how plants sense pathogen effectors during effector-triggered immunity (ETI). However, less is known about downstream signaling events. In this report, we demonstrate that prolonged activation of MPK3 and MPK6, two Arabidopsis pathogen-responsive mitogen-activated protein kinases (MPKs), is essential to ETI mediated by both coiled coil-nucleotide binding site-leucine rich repeats (CNLs) and toll/interleukin-1 receptor nucleotide binding site-leucine rich repeats (TNLs) types of R proteins. MPK3/MPK6 activation rapidly alters the expression of photosynthesis-related genes and inhibits photosynthesis, which promotes the accumulation of superoxide ( O2•−) and hydrogen peroxide (H2O2), two major reactive oxygen species (ROS), in chloroplasts under light. In the chemical-genetically rescued mpk3 mpk6 double mutants, ETI-induced photosynthetic inhibition and chloroplastic ROS accumulation are compromised, which correlates with delayed hypersensitive response (HR) cell death and compromised resistance. Furthermore, protection of chloroplasts by expressing a plastid-targeted cyanobacterial flavodoxin (pFLD) delays photosynthetic inhibition and compromises ETI. Collectively, this study highlights a critical role of MPK3/MPK6 in manipulating plant photosynthetic activities to promote ROS accumulation in chloroplasts and HR cell death, which contributes to the robustness of ETI. Furthermore, the dual functionality of MPK3/MPK6 cascade in promoting defense and inhibiting photosynthesis potentially allow it to orchestrate the trade-off between plant growth and defense in plant immunity. Plants follow different strategies to defend themselves against pathogens and activate their immune systems once the pathogens have been detected. One of the responses observed is the inhibition of photosynthesis and the global down-regulation of genes that regulate this process, similar to what is frequently observed in plants under various biotic stress conditions. However, the mechanisms underlying the turning off of the photosynthetic activity and whether this process contributes to plants’ defense against pathogens remain to be determined. In this study, we analyze these mechanisms in Arabidopsis plants and show that prolonged activation of MPK3 and MPK6, two kinases critical for pathogen resistance, results in the inhibition of photosynthesis and accumulation of reactive oxygen species (ROS) in the chloroplasts. We find that this response is similar to that observed during pathogen effector-triggered immunity (ETI). Correspondingly, plants that carry mutant versions of MPK3 and MPK6 result in compromised ETI-induced photosynthetic inhibition and chloroplastic ROS accumulation; thus, these two kinases seem to be essential for ETI. Our results suggest that MPK3/MPK6 activation induces a global down-regulation of photosynthesis along with an up-regulation of defense-related genes, and coordinates the growth and defense trade-off in plants.
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Affiliation(s)
- Jianbin Su
- Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
- Division of Biochemistry, Interdisciplinary Plant Group, and Bond Life Sciences Center, University of Missouri, Columbia, Missouri, United States of America
| | - Liuyi Yang
- Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Qiankun Zhu
- Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Hongjiao Wu
- Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Yi He
- Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Yidong Liu
- Division of Biochemistry, Interdisciplinary Plant Group, and Bond Life Sciences Center, University of Missouri, Columbia, Missouri, United States of America
| | - Juan Xu
- Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Dean Jiang
- Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Shuqun Zhang
- Division of Biochemistry, Interdisciplinary Plant Group, and Bond Life Sciences Center, University of Missouri, Columbia, Missouri, United States of America
- * E-mail:
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Gómez R, Carrillo N, Morelli MP, Tula S, Shahinnia F, Hajirezaei MR, Lodeyro AF. Faster photosynthetic induction in tobacco by expressing cyanobacterial flavodiiron proteins in chloroplasts. PHOTOSYNTHESIS RESEARCH 2018; 136:129-138. [PMID: 29022124 DOI: 10.1007/s11120-017-0449-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Accepted: 09/26/2017] [Indexed: 05/02/2023]
Abstract
Plants grown in the field experience sharp changes in irradiation due to shading effects caused by clouds, other leaves, etc. The excess of absorbed light energy is dissipated by a number of mechanisms including cyclic electron transport, photorespiration, and Mehler-type reactions. This protection is essential for survival but decreases photosynthetic efficiency. All phototrophs except angiosperms harbor flavodiiron proteins (Flvs) which relieve the excess of excitation energy on the photosynthetic electron transport chain by reducing oxygen directly to water. Introduction of cyanobacterial Flv1/Flv3 in tobacco chloroplasts resulted in transgenic plants that showed similar photosynthetic performance under steady-state illumination, but displayed faster recovery of various photosynthetic parameters, including electron transport and non-photochemical quenching during dark-light transitions. They also kept the electron transport chain in a more oxidized state and enhanced the proton motive force of dark-adapted leaves. The results indicate that, by acting as electron sinks during light transitions, Flvs contribute to increase photosynthesis protection and efficiency under changing environmental conditions as those found by plants in the field.
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Affiliation(s)
- Rodrigo Gómez
- Instituto de Biología Molecular y Celular de Rosario (IBR-UNR/CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario (UNR), 2000, Rosario, Argentina
| | - Néstor Carrillo
- Instituto de Biología Molecular y Celular de Rosario (IBR-UNR/CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario (UNR), 2000, Rosario, Argentina
| | - María P Morelli
- Instituto de Biología Molecular y Celular de Rosario (IBR-UNR/CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario (UNR), 2000, Rosario, Argentina
- Departamento de Química Biológica (QB 23), Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires (UBA), C1428EGA, Buenos Aires, Argentina
| | - Suresh Tula
- Leibniz Institute of Plant Genetics and Crop Plant Research, OT Gatersleben, Corrensstrasse, 06466, Stadt Seeland, Germany
| | - Fahimeh Shahinnia
- Leibniz Institute of Plant Genetics and Crop Plant Research, OT Gatersleben, Corrensstrasse, 06466, Stadt Seeland, Germany
| | - Mohammad-Reza Hajirezaei
- Leibniz Institute of Plant Genetics and Crop Plant Research, OT Gatersleben, Corrensstrasse, 06466, Stadt Seeland, Germany
| | - Anabella F Lodeyro
- Instituto de Biología Molecular y Celular de Rosario (IBR-UNR/CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario (UNR), 2000, Rosario, Argentina.
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Housset JM, Nadeau S, Isabel N, Depardieu C, Duchesne I, Lenz P, Girardin MP. Tree rings provide a new class of phenotypes for genetic associations that foster insights into adaptation of conifers to climate change. THE NEW PHYTOLOGIST 2018; 218:630-645. [PMID: 29314017 PMCID: PMC6079641 DOI: 10.1111/nph.14968] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Accepted: 11/21/2017] [Indexed: 05/20/2023]
Abstract
Local adaptation in tree species has been documented through a long history of common garden experiments where functional traits (height, bud phenology) are used as proxies for fitness. However, the ability to identify genes or genomic regions related to adaptation to climate requires the evaluation of traits that precisely reflect how and when climate exerts selective constraints. We combine dendroecology with association genetics to establish a link between genotypes, phenotypes and interannual climatic fluctuations. We illustrate this approach by examining individual tree responses embedded in the annual rings of 233 Pinus strobus trees growing in a common garden experiment representing 38 populations from the majority of its range. We found that interannual variability in growth was affected by low temperatures during spring and autumn, and by summer heat and drought. Among-population variation in climatic sensitivity was significantly correlated with the mean annual temperature of the provenance, suggesting local adaptation. Genotype-phenotype associations using these new tree-ring phenotypes validated nine candidate genes identified in a previous genetic-environment association study. Combining dendroecology with association genetics allowed us to assess tree vulnerability to past climate at fine temporal scales and provides avenues for future genomic studies on functional adaptation in forest trees.
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Affiliation(s)
- Johann M. Housset
- Natural Resources CanadaCanadian Forest ServiceLaurentian Forestry Centre1055 du P.E.P.S, PO Box 10380, Stn. Sainte‐FoyQuébecQCG1V 4C7Canada
- Natural Resources CanadaCanadian Wood Fibre Centre1055 du P.E.P.S, PO Box 10380, Stn. Sainte‐FoyQuébecQCG1V 4C7Canada
- Centre d’étude de la forêtUniversité du Québec à MontréalC.P. 8888, succ. Centre‐villeMontréalQCH3C 3P8Canada
| | - Simon Nadeau
- Natural Resources CanadaCanadian Forest ServiceLaurentian Forestry Centre1055 du P.E.P.S, PO Box 10380, Stn. Sainte‐FoyQuébecQCG1V 4C7Canada
- Natural Resources CanadaCanadian Wood Fibre Centre1055 du P.E.P.S, PO Box 10380, Stn. Sainte‐FoyQuébecQCG1V 4C7Canada
| | - Nathalie Isabel
- Natural Resources CanadaCanadian Forest ServiceLaurentian Forestry Centre1055 du P.E.P.S, PO Box 10380, Stn. Sainte‐FoyQuébecQCG1V 4C7Canada
- Chaire de Recherche du Canada en Génomique ForestièreFaculté de Foresteriede Géographie et de GéomatiqueUniversité LavalQuébecQCG1V 0A6Canada
| | - Claire Depardieu
- Natural Resources CanadaCanadian Forest ServiceLaurentian Forestry Centre1055 du P.E.P.S, PO Box 10380, Stn. Sainte‐FoyQuébecQCG1V 4C7Canada
- Chaire de Recherche du Canada en Génomique ForestièreFaculté de Foresteriede Géographie et de GéomatiqueUniversité LavalQuébecQCG1V 0A6Canada
| | - Isabelle Duchesne
- Natural Resources CanadaCanadian Wood Fibre Centre1055 du P.E.P.S, PO Box 10380, Stn. Sainte‐FoyQuébecQCG1V 4C7Canada
| | - Patrick Lenz
- Natural Resources CanadaCanadian Wood Fibre Centre1055 du P.E.P.S, PO Box 10380, Stn. Sainte‐FoyQuébecQCG1V 4C7Canada
- Chaire de Recherche du Canada en Génomique ForestièreFaculté de Foresteriede Géographie et de GéomatiqueUniversité LavalQuébecQCG1V 0A6Canada
| | - Martin P. Girardin
- Natural Resources CanadaCanadian Forest ServiceLaurentian Forestry Centre1055 du P.E.P.S, PO Box 10380, Stn. Sainte‐FoyQuébecQCG1V 4C7Canada
- Centre d’étude de la forêtUniversité du Québec à MontréalC.P. 8888, succ. Centre‐villeMontréalQCH3C 3P8Canada
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Mayta ML, Lodeyro AF, Guiamet JJ, Tognetti VB, Melzer M, Hajirezaei MR, Carrillo N. Expression of a Plastid-Targeted Flavodoxin Decreases Chloroplast Reactive Oxygen Species Accumulation and Delays Senescence in Aging Tobacco Leaves. FRONTIERS IN PLANT SCIENCE 2018; 9:1039. [PMID: 30065745 PMCID: PMC6056745 DOI: 10.3389/fpls.2018.01039] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Accepted: 06/26/2018] [Indexed: 05/02/2023]
Abstract
Leaf senescence is a concerted physiological process involving controlled degradation of cellular structures and reallocation of breakdown products to other plant organs. It is accompanied by increased production of reactive oxygen species (ROS) that are proposed to signal cell death, although both the origin and the precise role of ROS in the execution of this developmental program are still poorly understood. To investigate the contribution of chloroplast-associated ROS to natural leaf senescence, we used tobacco plants expressing a plastid-targeted flavodoxin, an electron shuttle flavoprotein present in prokaryotes and algae. When expressed in plants, flavodoxin specifically prevents ROS formation in chloroplasts during stress situations. Senescence symptoms were significantly mitigated in these transformants, with decreased accumulation of chloroplastic ROS and differential preservation of chlorophylls, carotenoids, protein contents, cell and chloroplast structures, membrane integrity and cell viability. Flavodoxin also improved maintenance of chlorophyll-protein complexes, photosynthetic electron flow, CO2 assimilation, central metabolic routes and levels of bioactive cytokinins and auxins in aging leaves. Delayed induction of senescence-associated genes indicates that the entire genetic program of senescence was affected by flavodoxin. The results suggest that ROS generated in chloroplasts are involved in the regulation of natural leaf senescence.
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Affiliation(s)
- Martín L. Mayta
- Instituto de Biología Molecular y Celular de Rosario (IBR-UNR/CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina
| | - Anabella F. Lodeyro
- Instituto de Biología Molecular y Celular de Rosario (IBR-UNR/CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina
| | - Juan J. Guiamet
- Instituto de Fisiología Vegetal (INFIVE–UNLP/CONICET), La Plata, Argentina
| | - Vanesa B. Tognetti
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Brno, Czechia
| | - Michael Melzer
- Leibniz Institute of Plant Genetics and Crop Plant Research, OT Gatersleben, Seeland, Germany
| | - Mohammad R. Hajirezaei
- Leibniz Institute of Plant Genetics and Crop Plant Research, OT Gatersleben, Seeland, Germany
- *Correspondence: Mohammad R. Hajirezaei, Néstor Carrillo,
| | - Néstor Carrillo
- Instituto de Biología Molecular y Celular de Rosario (IBR-UNR/CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina
- *Correspondence: Mohammad R. Hajirezaei, Néstor Carrillo,
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Rossi FR, Krapp AR, Bisaro F, Maiale SJ, Pieckenstain FL, Carrillo N. Reactive oxygen species generated in chloroplasts contribute to tobacco leaf infection by the necrotrophic fungus Botrytis cinerea. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2017; 92:761-773. [PMID: 28906064 DOI: 10.1111/tpj.13718] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Revised: 08/23/2017] [Accepted: 09/07/2017] [Indexed: 05/18/2023]
Abstract
Reactive oxygen species (ROS) play fundamental roles in plant responses to pathogen infection, including modulation of cell death processes and defense-related gene expression. Cell death triggered as part of the hypersensitive response enhances resistance to biotrophic pathogens, but favors the virulence of necrotrophs. Even though the involvement of ROS in the orchestration of defense responses is well established, the relative contribution of specific subcellular ROS sources to plant resistance against microorganisms with different pathogenesis strategies is not completely known. The aim of this work was to investigate the role of chloroplastic ROS in plant defense against a typical necrotrophic fungus, Botrytis cinerea. For this purpose, we used transgenic Nicotiana tabacum (tobacco) lines expressing a plastid-targeted cyanobacterial flavodoxin (pfld lines), which accumulate lower chloroplastic ROS in response to different stresses. Tissue damage and fungal growth were significantly reduced in infected leaves of pfld plants, as compared with infected wild-type (WT) counterparts. ROS build-up triggered by Botrytis infection and associated with chloroplasts was significantly decreased (70-80%) in pfld leaves relative to the wild type. Phytoalexin accumulation and expression of pathogenesis-related genes were induced to a lower degree in pfld plants than in WT siblings. The impact of fungal infection on photosynthetic activity was also lower in pfld leaves. The results indicate that chloroplast-generated ROS play a major role in lesion development during Botrytis infection. This work demonstrates that the modulation of chloroplastic ROS levels by the expression of a heterologous antioxidant protein can provide a significant degree of protection against a canonical necrotrophic fungus.
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Affiliation(s)
- Franco R Rossi
- Instituto de Investigaciones Biotecnológicas-Instituto Tecnológico Chascomús, Universidad Nacional de General San Martín, Consejo Nacional de Investigaciones Científicas y Técnicas (IIB-INTECH/UNSAM-CONICET), Chascomús, Argentina
| | - Adriana R Krapp
- Facultad de Ciencias Bioquímicas y Farmacéuticas, Instituto de Biología Molecular y Celular de Rosario (IBR-UNR/CONICET), Universidad Nacional de Rosario (UNR), Rosario, Argentina
| | - Fabiana Bisaro
- Facultad de Ciencias Bioquímicas y Farmacéuticas, Instituto de Biología Molecular y Celular de Rosario (IBR-UNR/CONICET), Universidad Nacional de Rosario (UNR), Rosario, Argentina
| | - Santiago J Maiale
- Instituto de Investigaciones Biotecnológicas-Instituto Tecnológico Chascomús, Universidad Nacional de General San Martín, Consejo Nacional de Investigaciones Científicas y Técnicas (IIB-INTECH/UNSAM-CONICET), Chascomús, Argentina
| | - Fernando L Pieckenstain
- Instituto de Investigaciones Biotecnológicas-Instituto Tecnológico Chascomús, Universidad Nacional de General San Martín, Consejo Nacional de Investigaciones Científicas y Técnicas (IIB-INTECH/UNSAM-CONICET), Chascomús, Argentina
| | - Néstor Carrillo
- Facultad de Ciencias Bioquímicas y Farmacéuticas, Instituto de Biología Molecular y Celular de Rosario (IBR-UNR/CONICET), Universidad Nacional de Rosario (UNR), Rosario, Argentina
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Mellor SB, Vavitsas K, Nielsen AZ, Jensen PE. Photosynthetic fuel for heterologous enzymes: the role of electron carrier proteins. PHOTOSYNTHESIS RESEARCH 2017; 134:329-342. [PMID: 28285375 DOI: 10.1007/s11120-017-0364-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Accepted: 02/27/2017] [Indexed: 05/21/2023]
Abstract
Plants, cyanobacteria, and algae generate a surplus of redox power through photosynthesis, which makes them attractive for biotechnological exploitations. While central metabolism consumes most of the energy, pathways introduced through metabolic engineering can also tap into this source of reducing power. Recent work on the metabolic engineering of photosynthetic organisms has shown that the electron carriers such as ferredoxin and flavodoxin can be used to couple heterologous enzymes to photosynthetic reducing power. Because these proteins have a plethora of interaction partners and rely on electrostatically steered complex formation, they form productive electron transfer complexes with non-native enzymes. A handful of examples demonstrate channeling of photosynthetic electrons to drive the activity of heterologous enzymes, and these focus mainly on hydrogenases and cytochrome P450s. However, competition from native pathways and inefficient electron transfer rates present major obstacles, which limit the productivity of heterologous reactions coupled to photosynthesis. We discuss specific approaches to address these bottlenecks and ensure high productivity of such enzymes in a photosynthetic context.
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Affiliation(s)
- Silas Busck Mellor
- Copenhagen Plant Science Center, Center for Synthetic Biology 'bioSYNergy', Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871, Frederiksberg C, Denmark
| | - Konstantinos Vavitsas
- Copenhagen Plant Science Center, Center for Synthetic Biology 'bioSYNergy', Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871, Frederiksberg C, Denmark
| | - Agnieszka Zygadlo Nielsen
- Copenhagen Plant Science Center, Center for Synthetic Biology 'bioSYNergy', Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871, Frederiksberg C, Denmark
| | - Poul Erik Jensen
- Copenhagen Plant Science Center, Center for Synthetic Biology 'bioSYNergy', Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871, Frederiksberg C, Denmark.
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49
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Pierella Karlusich JJ, Carrillo N. Evolution of the acceptor side of photosystem I: ferredoxin, flavodoxin, and ferredoxin-NADP + oxidoreductase. PHOTOSYNTHESIS RESEARCH 2017; 134:235-250. [PMID: 28150152 DOI: 10.1007/s11120-017-0338-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Accepted: 01/12/2017] [Indexed: 05/21/2023]
Abstract
The development of oxygenic photosynthesis by primordial cyanobacteria ~2.7 billion years ago led to major changes in the components and organization of photosynthetic electron transport to cope with the challenges of an oxygen-enriched atmosphere. We review herein, following the seminal contributions as reported by Jaganathan et al. (Functional genomics and evolution of photosynthetic systems, vol 33, advances in photosynthesis and respiration, Springer, Dordrecht, 2012), how these changes affected carriers and enzymes at the acceptor side of photosystem I (PSI): the electron shuttle ferredoxin (Fd), its isofunctional counterpart flavodoxin (Fld), their redox partner ferredoxin-NADP+ reductase (FNR), and the primary PSI acceptors F x and F A/F B. Protection of the [4Fe-4S] centers of these proteins from oxidative damage was achieved by strengthening binding between the F A/F B polypeptide and the reaction center core containing F x, therefore impairing O2 access to the clusters. Immobilization of F A/F B in the PSI complex led in turn to the recruitment of new soluble electron shuttles. This function was fulfilled by oxygen-insensitive [2Fe-2S] Fd, in which the reactive sulfide atoms of the cluster are shielded from solvent by the polypeptide backbone, and in some algae and cyanobacteria by Fld, which employs a flavin as prosthetic group and is tolerant to oxidants and iron limitation. Tight membrane binding of FNR allowed solid-state electron transfer from PSI bridged by Fd/Fld. Fine tuning of FNR catalytic mechanism led to formidable increases in turnover rates compared with FNRs acting in heterotrophic pathways, favoring Fd/Fld reduction instead of oxygen reduction.
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Affiliation(s)
- Juan José Pierella Karlusich
- Instituto de Biología Molecular y Celular de Rosario (IBR-UNR/CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario (UNR), Ocampo y Esmeralda, 2000, Rosario, Argentina
| | - Néstor Carrillo
- Instituto de Biología Molecular y Celular de Rosario (IBR-UNR/CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario (UNR), Ocampo y Esmeralda, 2000, Rosario, Argentina.
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50
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Holzinger A, Herburger K, Blaas K, Lewis LA, Karsten U. The terrestrial green macroalga Prasiola calophylla (Trebouxiophyceae, Chlorophyta): ecophysiological performance under water-limiting conditions. PROTOPLASMA 2017; 254:1755-1767. [PMID: 28066876 PMCID: PMC5474099 DOI: 10.1007/s00709-016-1068-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Accepted: 12/21/2016] [Indexed: 05/22/2023]
Abstract
The phylogenetic placement of Prasiola calophylla, from an anthropogenic habitat previously shown to contain a novel UV sunscreen compound, was confirmed by analysis of its rbcL gene. This alga has the capacity to tolerate strong water-limiting conditions. The photosynthetic performance and ultrastructural changes under desiccation and osmotic stress were investigated. Freshly harvested thalli showed an effective quantum yield of PSII [Y(II)] of 0.52 ± 0.06 that decreased to ∼60% of the initial value at 3000 mM sorbitol, and 4000 mM sorbitol led to a complete loss of Y(II). The Y(II) of thalli exposed to controlled desiccating conditions at 60% relative humidity (RH) ceased within 240 min, whereas zero values were reached after 120 min at 20% RH. All investigated samples completely recovered Y(II) within ∼100 min after rehydration. Relative electron transport rates (rETR) were temperature dependent, increasing from 5, 10, to 25 °C but strongly declining at 45 °C. Transmission electron microscopy of samples desiccated for 2.5 h showed an electron dense appearance of the entire cytoplasm when compared to control samples. Thylakoid membranes were still visible in desiccated cells, corroborating the ability to recover. Control and desiccated cells contained numerous storage lipids and starch grains, providing reserves. Overall, P. calophylla showed a high capacity to cope with water-limiting conditions on a physiological and structural basis. A lipophilic outer layer of the cell walls might contribute to reduce water evaporation in this poikilohydric organism.
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Affiliation(s)
- Andreas Holzinger
- Functional Plant Biology, Institute of Botany, University of Innsbruck, Sternwartestrasse 15, 6020, Innsbruck, Austria.
| | - Klaus Herburger
- Functional Plant Biology, Institute of Botany, University of Innsbruck, Sternwartestrasse 15, 6020, Innsbruck, Austria
| | - Kathrin Blaas
- Functional Plant Biology, Institute of Botany, University of Innsbruck, Sternwartestrasse 15, 6020, Innsbruck, Austria
| | - Louise A Lewis
- Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT, 06269-3043, USA
| | - Ulf Karsten
- Institute of Biological Sciences, Applied Ecology and Phycology, University of Rostock, Albert-Einstein-Straße 3, 18059, Rostock, Germany
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