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Smith KE, Cowan L, Taylor B, McAusland L, Heatley M, Yant L, Murchie EH. Physiological adaptation to irradiance in duckweeds is species and accession specific and depends on light habitat niche. JOURNAL OF EXPERIMENTAL BOTANY 2024; 75:2046-2063. [PMID: 38217537 DOI: 10.1093/jxb/erad499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Accepted: 01/09/2024] [Indexed: 01/15/2024]
Abstract
Duckweeds span 36 species of free-floating aquatic organisms with body sizes ranging from 2 mm to 10 mm, where each plant body plan is reduced to a largely leaf-like structure. As an emerging crop, their fast growth rates offer potential for cultivation in closed systems. We describe a novel UK collection derived from low light (dLL) or high light (dHL) habitats, profiled for growth, photosynthesis, and photoprotection (non-photochemical quenching, NPQ) responses. Twenty-three accessions of three Lemna species and one Spirodela polyrhiza were grown under relatively low light (LL: 100 μmol m-2 s-1) and high light (HL: 350 μmol m-2 s-1) intensities. We observed broad within- and between-species level variation in photosynthesis acclimation. Duckweeds grown under HL exhibited a lower growth rate, biomass, chlorophyll, and quantum yield of photosynthesis. In HL compared with LL, carotenoid de-epoxidation state and NPQ were higher, whilst PSII efficiency (φPSII) and Chl a:b ratios were unchanged. The dLL plants showed relatively stronger acclimation to HL compared with dHL plants, especially Lemna japonica accessions. These achieved faster growth in HL with concurrent higher carotenoid levels and NPQ, and less degradation of chlorophyll. We conclude that these data support local adaptation to the light environment in duckweed affecting acclimation in controlled conditions.
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Affiliation(s)
- Kellie E Smith
- Division of Plant and Crop Sciences, School of Biosciences, University of Nottingham, Sutton Bonington LE12 5RD, UK
- School of Life Sciences, University of Nottingham, Nottingham NG7 2RD, UK
| | - Laura Cowan
- School of Life Sciences, University of Nottingham, Nottingham NG7 2RD, UK
| | - Beth Taylor
- Division of Plant and Crop Sciences, School of Biosciences, University of Nottingham, Sutton Bonington LE12 5RD, UK
| | - Lorna McAusland
- Division of Plant and Crop Sciences, School of Biosciences, University of Nottingham, Sutton Bonington LE12 5RD, UK
| | - Matthew Heatley
- School of Life Sciences, University of Nottingham, Nottingham NG7 2RD, UK
| | - Levi Yant
- School of Life Sciences, University of Nottingham, Nottingham NG7 2RD, UK
| | - Erik H Murchie
- Division of Plant and Crop Sciences, School of Biosciences, University of Nottingham, Sutton Bonington LE12 5RD, UK
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Xie L, Solhaug KA, Song Y, Johnsen B, Olsen JE, Tollefsen KE. Effects of artificial ultraviolet B radiation on the macrophyte Lemna minor: a conceptual study for toxicity pathway characterization. PLANTA 2020; 252:86. [PMID: 33057834 PMCID: PMC7560917 DOI: 10.1007/s00425-020-03482-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Accepted: 09/28/2020] [Indexed: 06/11/2023]
Abstract
UVB radiation caused irradiance-dependent and target-specific responses in non-UVB acclimated Lemna minor. Conceptual toxicity pathways were developed to propose causal relationships between UVB-mediated effects at multiple levels of biological organisation. Macrophytes inhabit waterways around the world and are used in hydroponics or aquaponics for different purposes such as feed and wastewater treatment and are thus exposed to elevated levels of UVB from natural and artificial sources. Although high UVB levels are harmful to macrophytes, mechanistic understanding of irradiance-dependent effects and associated modes of action in non-UVB acclimated plants still remains low. The present study was conducted to characterise the irradiance-dependent mechanisms of UVB leading to growth inhibition in Lemna minor as an aquatic macrophyte model. The L. minor were continuously exposed to UVB (0.008-4.2 W m-2) and constant UVA (4 W m-2) and photosynthetically active radiation, PAR (80 µmol m-2 s-1) for 7 days. A suite of bioassays was deployed to assess effects on oxidative stress, photosynthesis, DNA damage, and transcription of antioxidant biosynthesis, DNA repair, programmed cell death, pigment metabolism and respiration. The results showed that UVB triggered both irradiance-dependent and target-specific effects at multiple levels of biological organization, whereas exposure to UVA alone did not cause any effects. Inhibition of photosystem II and induction of carotenoids were observed at 0.23 W m-2, whereas growth inhibition, excessive reactive oxygen species, lipid peroxidation, cyclobutane pyrimidine dimer formation, mitochondrial membrane potential reduction and chlorophyll depletion were observed at 0.5-1 W m-2. Relationships between responses at different levels of biological organization were used to establish a putative network of toxicity pathways to improve our understanding of UVB effects in aquatic macrophytes under continuous UVB exposures. Additional studies under natural illuminations were proposed to assess whether these putative toxicity pathways may also be relevant for more ecologically relevant exposure scenarios.
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Affiliation(s)
- Li Xie
- Section of Ecotoxicology and Risk Assessment, Norwegian Institute for Water Research (NIVA), Gaustadalléen 21, 0349, Oslo, Norway
- Centre for Environmental Radioactivity, Norwegian University of Life Sciences (NMBU), Post Box 5003, 1432, Ås, Norway
| | - Knut Asbjørn Solhaug
- Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, 1432, Ås, Norway
- Centre for Environmental Radioactivity, Norwegian University of Life Sciences (NMBU), Post Box 5003, 1432, Ås, Norway
| | - You Song
- Section of Ecotoxicology and Risk Assessment, Norwegian Institute for Water Research (NIVA), Gaustadalléen 21, 0349, Oslo, Norway
- Centre for Environmental Radioactivity, Norwegian University of Life Sciences (NMBU), Post Box 5003, 1432, Ås, Norway
| | - Bjørn Johnsen
- Centre for Environmental Radioactivity, Norwegian University of Life Sciences (NMBU), Post Box 5003, 1432, Ås, Norway
- Norwegian Radiation and Nuclear Safety Authority (DSA), 1361, Østerås, Norway
| | - Jorunn Elisabeth Olsen
- Centre for Environmental Radioactivity, Norwegian University of Life Sciences (NMBU), Post Box 5003, 1432, Ås, Norway
- Faculty of Biosciences, Institute of Plant Sciences, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, 1432, Ås, Norway
| | - Knut Erik Tollefsen
- Section of Ecotoxicology and Risk Assessment, Norwegian Institute for Water Research (NIVA), Gaustadalléen 21, 0349, Oslo, Norway.
- Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, 1432, Ås, Norway.
- Centre for Environmental Radioactivity, Norwegian University of Life Sciences (NMBU), Post Box 5003, 1432, Ås, Norway.
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An D, Li C, Zhou Y, Wu Y, Wang W. Genomes and Transcriptomes of Duckweeds. Front Chem 2018; 6:230. [PMID: 29974050 PMCID: PMC6019479 DOI: 10.3389/fchem.2018.00230] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Accepted: 05/31/2018] [Indexed: 11/23/2022] Open
Abstract
Duckweeds (Lemnaceae family) are the smallest flowering plants that adapt to the aquatic environment. They are regarded as the promising sustainable feedstock with the characteristics of high starch storage, fast propagation, and global distribution. The duckweed genome size varies 13-fold ranging from 150 Mb in Spirodela polyrhiza to 1,881 Mb in Wolffia arrhiza. With the development of sequencing technology and bioinformatics, five duckweed genomes from Spirodela and Lemna genera are sequenced and assembled. The genome annotations discover that they share similar protein orthologs, whereas the repeat contents could mainly explain the genome size difference. The gene families responsible for cell growth and expansion, lignin biosynthesis, and flowering are greatly contracted. However, the gene family of glutamate synthase has experienced expansion, indicating their significance in ammonia assimilation and nitrogen transport. The transcriptome is comprehensively sequenced for the genera of Spirodela, Landoltia, and Lemna, including various treatments such as abscisic acid, radiation, heavy metal, and starvation. The analysis of the underlying molecular mechanism and the regulatory network would accelerate their applications in the fields of bioenergy and phytoremediation. The comparative genomics has shown that duckweed genomes contain relatively low gene numbers and more contracted gene families, which may be in parallel with their highly reduced morphology with a simple leaf and primary roots. Still, we are waiting for the advancement of the long read sequencing technology to resolve the complex genomes and transcriptomes for unsequenced Wolffiella and Wolffia due to the large genome sizes and the similarity in their polyploidy.
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Affiliation(s)
- Dong An
- Department of Plant Sciences, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Changsheng Li
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Yong Zhou
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Yongrui Wu
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Wenqin Wang
- Department of Plant Sciences, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
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Ray RS, Agrawal N, Misra RB, Farooq M, Hans RK. Radiation-Inducedin VitroPhototoxic Potential of Some Fluoroquinolones. Drug Chem Toxicol 2008; 29:25-38. [PMID: 16455588 DOI: 10.1080/01480540500408572] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Photosensitizing drugs that can damage cellular biomolecules is a matter of concern. Lomefloxacin, norfloxacin, ofloxacin, and enoxacin (broad-spectrum antibiotics of fluoroquinolone group) are used for the treatment of Gram-positive and Gram-negative bacterial infections. Phototoxicity and possible mechanism of their action was assessed under the exposure of ambient levels of UV-A, UV-B, and sunlight at a concentration generally used in the treatment of various diseases. Singlet oxygen (1O2), superoxide anion radical (O2.-) generation, DNA damage, and lipid peroxidation in human blood were studied. All the fluoroquinolones tested in this study produced 1O2 and O2.- under exposure to UV-A, UV-B, and sunlight depending on the concentrations (0 to 60 microg/mL) of the drugs. Enoxacin showed a higher yield of 1O2 and O2.- than other drugs. These materials also degraded deoxyguanosine and induced lipid peroxidation in vitro under exposure to UV-A, UV-B, and sunlight (depending on the dose of radiation). The formation of the reactive oxygen species (ROS) by the photoexcited drugs may be considered as a possible mechanism of their action.
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Affiliation(s)
- R S Ray
- Photobiology Division, Industrial Toxicology Research Centre, Lucknow, India
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Ray R, Agrawal N, Sharma A, Hans R. Use of L-929 cell line for phototoxicity assessment. Toxicol In Vitro 2008; 22:1775-81. [DOI: 10.1016/j.tiv.2008.06.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2007] [Revised: 04/17/2008] [Accepted: 06/05/2008] [Indexed: 10/21/2022]
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Masood A, Zeeshan M, Abraham G. Response of growth and antioxidant enzymes in Azolla plants (Azolla pinnata and Azolla filiculoides) exposed to UV-B. ACTA BIOLOGICA HUNGARICA 2008; 59:247-58. [PMID: 18637563 DOI: 10.1556/abiol.59.2008.2.10] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Effect of ultravilolet-B (0.4 Wm(-2)) irradiation on growth, flavonoid content, lipid peroxidation, proline accumulation and activities of superoxide dismutase and peroxidase was comparatively analysed in Azolla pinnata and Azolla filiculoides. Growth measured as increment in dry weight reduced considerably due to all UV-B treatments. However, the reduction was found to be severe in A. filiculoides as compared to A. pinnata. The level of UV-absorbing compound flavonoids increased significantly in A. pinnata plants whereas only a slight increase in the flavonoid content was observed in A. filiculoides. UV-B exposure led to enhanced production of malondialdehyde (MDA) and electrolyte leakage in A. filiculoides than A. pinnata. Proline accumulation also showed a similar trend. Marked differences in the activity of antioxidant enzymes such as superoxide dismutase (SOD) and peroxidase (POD) was noticed in both the plants exposed to UV-B. Our comparative studies indicate A. pinnata to be better tolerant to UV-B as compared with A. filiculoides which appears to be sensitive.
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Affiliation(s)
- Amjad Masood
- Department of Botany, Allahabad Agriculture Institute, Deemed University, Allahabad-211007, India
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Farooq M, Shankar U, Ray RS, Misra RB, Agrawal N, Verma K, Hans RK. Morphological and metabolic alterations in duckweed (Spirodela polyrhiza) on long-term low-level chronic UV-B exposure. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2005; 62:408-14. [PMID: 16216635 DOI: 10.1016/j.ecoenv.2005.01.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2004] [Revised: 01/04/2005] [Accepted: 01/28/2005] [Indexed: 05/04/2023]
Abstract
Laboratory grown duckweed (Spirodela polyrhiza) plants were exposed to 0.72 and 1.44J of UV-B radiation daily for 7 days at 0.4mW/cm(2) intensity. Chlorosis and necrosis were observed along with depletion in protein, pigments (chlorophyll, pheophytin, carotenoids, phycoerythrin, phycocyanin, and flavoxanthin), biomass, root length, and frond size in UV-B-exposed plants. The study confirms morphological and metabolic alterations leading to reduction in the productivity of duckweed following long-term exposure to UV-B radiation.
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Affiliation(s)
- M Farooq
- Photobiology Division, Industrial Toxicology Research Centre, Mahatma Gandhi Marg, Post Box No. 80, Lucknow 226001, India
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Misra RB, Ray RS, Hans RK. Effect of UVB radiation on human erythrocytes in vitro. Toxicol In Vitro 2005; 19:433-8. [PMID: 15713550 DOI: 10.1016/j.tiv.2004.12.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2004] [Revised: 12/22/2004] [Accepted: 12/23/2004] [Indexed: 11/23/2022]
Abstract
In order to evaluate the UVB radiation induced phototoxic effect, the human erythrocytes (RBCs) were used an alternate biological model and rate of photohaemolysis was assessed in vitro at various intensities of UVB radiation (0-2.0 mW/cm2) for an exposure period of 0-240 min. The alterations of biochemical activities in RBC membrane (ghosts), caused by its exposure under an average incident intensity of UVB radiation (0.5 mW/cm2) in sunlight at earth surface, were also determined to understand the possible mechanism of photohaemolysis. We observed UVB dose dependent lysis of erythrocytes by recording haemoglobin and methemoglobin (oxidized form of haemoglobin) in photohaemolysate. We also observed significant inhibition in ATPase, acetylcholinesterase, glucose-6-phosphate dehydrogenase activites and an increased amount of thiobarbituric acid-reactive substance (TBA-RS) in RBC ghosts exposed to UVB radiation (0.5 mW/cm2) for a period of 0-100 min (doses: 0, 0.33, 0.66, 1.0, 1.5 and 3.0 J). The changes were found UVB dose dependent. A decrease of glutathione content in RBC ghosts at low dose level of UVB exposure (0.33 J) was found to be recovered at higher dose levels (0.66-1.5 J). These observations suggested, UVB dose dependent toxicity to human erythrocytes in vitro. Thus the erythrocytes can be used for an assessment of UVB induced biological effects and to understand possible mechanism of the phototoxicity.
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Affiliation(s)
- R B Misra
- Photobiology Laboratory, Industrial Toxicology Research Centre, Post Box No. 80, M.G. Marg, Lucknow 226 001, India.
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Tkalec M, Malarić K, Pevalek-Kozlina B. Influence of 400, 900, and 1900 MHz electromagnetic fields onLemna minor growth and peroxidase activity. Bioelectromagnetics 2005; 26:185-93. [PMID: 15768427 DOI: 10.1002/bem.20104] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Increased use of radio and microwave frequencies requires investigations of their effects on living organisms. Duckweed (Lemna minor L.) has been commonly used as a model plant for environmental monitoring. In the present study, duckweed growth and peroxidase activity was evaluated after exposure in a Gigahertz Transversal Electromagnetic (GTEM) cell to electric fields of frequencies 400, 900, and 1900 MHz. The growth of plants exposed for 2 h to the 23 V/m electric field of 900 MHz significantly decreased in comparison with the control, while an electric field of the same strength but at 400 MHz did not have such effect. A modulated field at 900 MHz strongly inhibited the growth, while at 400 MHz modulation did not influence the growth significantly. At both frequencies a longer exposure mostly decreased the growth and the highest electric field (390 V/m) strongly inhibited the growth. Exposure of plants to lower field strength (10 V/m) for 14 h caused significant decrease at 400 and 1900 MHz while 900 MHz did not influence the growth. Peroxidase activity in exposed plants varied, depending on the exposure characteristics. Observed changes were mostly small, except in plants exposed for 2 h to 41 V/m at 900 MHz where a significant increase (41%) was found. Our results suggest that investigated electromagnetic fields (EMFs) might influence plant growth and, to some extent, peroxidase activity. However, the effects of EMFs strongly depended on the characteristics of the field exposure.
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Affiliation(s)
- Mirta Tkalec
- Department of Botany, Faculty of Science, University of Zagreb, HR-10000 Zagreb, Croatia.
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