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Yang Y, Han X, Liang Y, Ghosh A, Chen J, Tang M. The Combined Effects of Arbuscular Mycorrhizal Fungi (AMF) and Lead (Pb) Stress on Pb Accumulation, Plant Growth Parameters, Photosynthesis, and Antioxidant Enzymes in Robinia pseudoacacia L. PLoS One 2015; 10:e0145726. [PMID: 26698576 PMCID: PMC4689355 DOI: 10.1371/journal.pone.0145726] [Citation(s) in RCA: 113] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Accepted: 12/08/2015] [Indexed: 12/02/2022] Open
Abstract
Arbuscular mycorrhizal fungi (AMF) are considered as a potential biotechnological tool for improving phytostabilization efficiency and plant tolerance to heavy metal-contaminated soils. However, the mechanisms through which AMF help to alleviate metal toxicity in plants are still poorly understood. A greenhouse experiment was conducted to evaluate the effects of two AMF species (Funneliformis mosseae and Rhizophagus intraradices) on the growth, Pb accumulation, photosynthesis and antioxidant enzyme activities of a leguminous tree (Robinia pseudoacacia L.) at Pb addition levels of 0, 500, 1000 and 2000 mg kg-1 soil. AMF symbiosis decreased Pb concentrations in the leaves and promoted the accumulation of biomass as well as photosynthetic pigment contents. Mycorrhizal plants had higher gas exchange capacity, non-photochemistry efficiency, and photochemistry efficiency compared with non-mycorrhizal plants. The enzymatic activities of superoxide dismutase (SOD), ascorbate peroxidases (APX) and glutathione peroxidase (GPX) were enhanced, and hydrogen peroxide (H2O2) and malondialdehyde (MDA) contents were reduced in mycorrhizal plants. These findings suggested that AMF symbiosis could protect plants by alleviating cellular oxidative damage in response to Pb stress. Furthermore, mycorrhizal dependency on plants increased with increasing Pb stress levels, indicating that AMF inoculation likely played a more important role in plant Pb tolerance in heavily contaminated soils. Overall, both F. mosseae and R. intraradices were able to maintain efficient symbiosis with R. pseudoacacia in Pb polluted soils. AMF symbiosis can improve photosynthesis and reactive oxygen species (ROS) scavenging capabilities and decrease Pb concentrations in leaves to alleviate Pb toxicity in R. pseudoacacia. Our results suggest that the application of the two AMF species associated with R. pseudoacacia could be a promising strategy for enhancing the phytostabilization efficiency of Pb contaminated soils.
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Affiliation(s)
- Yurong Yang
- State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Northwest A&F University, Yangling, Shaanxi 712100, China
- College of Forestry, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Xiaozhen Han
- Plant Systems Biology Lab, Botany and Plant Science, School of Natural Sciences, National University of Ireland, Galway, Ireland
| | - Yan Liang
- Joint BioEnergy Institute, 5885 Hollis St, Emeryville, California 94608, United States of America
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States of America
| | - Amit Ghosh
- School of Energy Science and Engineering, PK Sinha Centre for Bioenergy, Indian Institute of Technology Kharagpur, Kharagpur 721302, India
| | - Jie Chen
- College of Forestry, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Ming Tang
- College of Forestry, Northwest A&F University, Yangling, Shaanxi 712100, China
- * E-mail:
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Zhang X, Gong Z. Fluorescent transgenic zebrafish Tg(nkx2.2a:mEGFP) provides a highly sensitive monitoring tool for neurotoxins. PLoS One 2013; 8:e55474. [PMID: 23383332 PMCID: PMC3562320 DOI: 10.1371/journal.pone.0055474] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2012] [Accepted: 12/23/2012] [Indexed: 11/25/2022] Open
Abstract
Previously a standard toxicological test termed as DarT (Danio rerio Teratogenic assay) using wild type zebrafish embryos has been established and it is widely applied in toxicological and chemical screenings. As an increasing number of fluorescent transgenic zebrafish lines with specific fluorescent protein expression specifically expressed in different organs and tissues, we envision that the fluorescent markers may provide more sensitive endpoints for monitoring chemical induced phenotypical changes. Here we employed Tg(nkx2.2a:mEGFP) transgenic zebrafish which have GFP expression in the central nervous system to investigate its potential for screening neurotoxic chemicals. Five potential neurotoxins (acetaminophen, atenolol, atrazine, ethanol and lindane) and one neuroprotectant (mefenamic acid) were tested. We found that the GFP-labeled ventral axons from trunk motoneurons, which were easily observed in live fry and measured for quantification, were a highly sensitive to all of the five neurotoxins and the length of axons was significantly reduced in fry which looked normal based on DarT endpoints at low concentrations of neurotoxins. Compared to the most sensitive endpoints of DarT, ventral axon marker could improve the detection limit of these neurotoxins by about 10 fold. In contrast, there was no improvement for detection of the mefenamic acid compared to all DarT endpoints. Thus, ventral axon lengths provide a convenient and measureable marker specifically for neurotoxins. Our study may open a new avenue to use other fluorescent transgenic zebrafish embryos/fry to develop sensitive and specific toxicological tests for different categories of chemicals.
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Affiliation(s)
- Xiaoyan Zhang
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
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Bajkán S, Váradi G, Balogh M, Domonkos A, Kiss GB, Kovács L, Lehoczki E. Conserved structure of the chloroplast-DNA encoded D1 protein is essential for effective photoprotection via non-photochemical thermal dissipation in higher plants. Mol Genet Genomics 2010; 284:55-63. [PMID: 20526616 DOI: 10.1007/s00438-010-0549-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2009] [Accepted: 05/24/2010] [Indexed: 11/30/2022]
Abstract
Naturally selected atrazine-resistant (AR) weeds possessing a Ser(264) --> Gly D1 protein encoded by a mutant psbA allele in the chloroplast-DNA have increased photosensitivity and lower fitness. The D1 mutant lines of S. nigrum revealed impaired regulation of photosystem II (PSII) activity as compared with the wild-type plants resulting in a less effective photochemical light utilization and in addition, a lower capacity of non-photochemical thermal dissipation (NPQ), one of the main photoprotective mechanisms in oxygenic photosynthetic organisms. In this work, comparative chlorophyll fluorescence analysis in attached leaves of wild-type and AR Solanum nigrum L. and in their reciprocal crosses has been used to establish how the lower NPQ is inherited. Both a 50% reduction in steady-state NPQ and a 60-70% reduction in the rapidly reversible, energy-dependent (qE) component of NPQ were common phenomena in the parent and hybrid lines of D1 mutant S. nigrum. The nuclear hybrid status of the F2 plant material was confirmed by morphological observations on fully developed leaves. No alteration was found in the nucleotide sequence and the deduced amino acid sequences of the nuclear psbS gene isolated from different biotypes of S. nigrum, and there were no differences in the expressions of both the PsbS and the D1 proteins. All things considered, co-inheritance of the lower photoprotective NPQ capacity and the Ser(264) --> Gly D1 protein mutation was clearly observed, suggesting that the evolutionarily conserved D1 structure must be indispensable for the efficient NPQ process in higher plants.
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Affiliation(s)
- Szilvia Bajkán
- Department of Plant Biology, University of Szeged, Szeged, Hungary.
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Barhoumi Z, Djebali W, Chaïbi W, Abdelly C, Smaoui A. Salt impact on photosynthesis and leaf ultrastructure of Aeluropus littoralis. JOURNAL OF PLANT RESEARCH 2007; 120:529-37. [PMID: 17534691 DOI: 10.1007/s10265-007-0094-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2006] [Accepted: 04/07/2007] [Indexed: 05/15/2023]
Abstract
The effects of salinity (400 mM NaCl) on growth, biomass partitioning, photosynthesis, and leaf ultrastructure were studied in hydroponically grown plants of Aeluropus littoralis (Willd) Parl. NaCl produced a significant inhibition of the main growth parameters and a reduction in leaf gas exchange (e.g. decreased rates of photosynthesis and stomatal conductance). However, NaCl salinity affected neither the composition of photosynthesis pigments nor leaf water content. The reduction in leaf gas exchange seemed to correlate with a decrease in mesophyll thickness as well as a severe disorganisation of chloroplast structure, with misshapen chloroplasts and dilated thylakoid membranes. Conspicuously, mesophyll chloroplasts were more sensitive to salt treatment than those of bundle sheath cells. The effects of NaCl toxicity on leaf structure and ultrastructure and the associated physiological implications are discussed in relation to the degree of salt resistance of A. littoralis.
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Affiliation(s)
- Zouhaier Barhoumi
- Laboratoire d'Adaptation des Plantes aux Stress Abiotiques, Centre de Biotechnologie de la Technopole de Borj-Cedria, BP 901, Hammam-Lif, 2050, Tunisia.
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Carr H, Björk M. Parallel changes in non-photochemical quenching properties, photosynthesis and D1 levels at sudden, prolonged irradiance exposures in Ulva fasciata Delile. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 2007; 87:18-26. [PMID: 17270459 DOI: 10.1016/j.jphotobiol.2006.12.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2006] [Accepted: 12/13/2006] [Indexed: 05/13/2023]
Abstract
The photosynthetic response to a sudden and prolonged high irradiance exposure and following recovery at low irradiance were studied with the aim of investigating the ability to withstand and adapt to high irradiance without prior high light adaptation. When thalli of Ulva fasciata, accustomed to a low irradiance (80 micromol photons m(-2) s(-1)), were exposed to a high irradiance (1500 micromol photons m(-2) s(-1)), the D1 protein was rapidly degraded, reaching a steady-state level after 110 min. This was followed by a fast recovery when thalli were transferred to dim light. The overall ability of non-photochemical quenching of chlorophyll fluorescence decreased and levelled off at a sudden and prolonged exposure to high irradiance and followed the same trend as the D1 level with a fast recovery in dim light. Ulva had intrinsic means to acclimate rapidly to high irradiance, when non-photochemical quenching did not operate properly, by maintaining a smaller fraction of high light tolerant PSII assemblages and by maintaining a high non-photochemical quenching capacity of chlorophyll fluorescence in relation to the variable fluorescence. The overall absorption of light (400-700 nm) remained high during the period of high irradiance exposure. When Ulva were deprived of nutrients in the form of PES media the ability of non-photochemical quenching decreased at photoinhibitory conditions. The possible causes for the responses at prolonged irradiance and the mechanisms for the decrease of non-photochemical quenching are discussed, with implications for field measurements.
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Affiliation(s)
- Herman Carr
- Botany Department, Stockholm University, Lilla Frescativägen 5, SE-106 91, Stockholm, Sweden.
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Drazkiewicz M, Baszyński T. Growth parameters and photosynthetic pigments in leaf segments of Zea mays exposed to cadmium, as related to protection mechanisms. JOURNAL OF PLANT PHYSIOLOGY 2005; 162:1013-21. [PMID: 16173462 DOI: 10.1016/j.jplph.2004.10.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The influence of cadmium on growth parameters and photosynthetic pigment content was studied in maize leaf segments differing in tissue maturity. Experiments were carried out with maize seedlings Zea mays L. cv. Hidosil treated with 25, 50, 100, 150 and 200 microM Cd for 14 days under low light conditions. Tissue age-dependent decrease of fresh mass, dry mass and area of the leaf segments was correlated with Cd concentration in the growth medium. Cd induced changes in chlorophyll and carotenoid contents, and the specific areas and densities of the leaf segments were dependent on age and metal concentration. Results are discussed with respect to the protection mechanisms in the leaf segments.
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Affiliation(s)
- Maria Drazkiewicz
- Department of Plant Physiology, Maria Curie-Skłodowska University, Akademicka 19, 20-033 Lublin, Poland.
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