Abiotic Stress Responses in Plants: Potential Targets on Studying Heavy Metal Stress tolerance in Bryophytes

2017 ◽  
Vol 3 (01) ◽  
pp. 41-51
Author(s):  
Anjana Singh ◽  
Rekha Tyagi ◽  
Anjuli Sood ◽  
P. L. Uniyal

Pollution of the biosphere with heavy metals has phenomenally increased since the commencement of industrial revolution. It poses several environment and health concerns. High regeneration and metal accumulation capacity the possibility of genetic transformation by homologous recombination extend the candidature of bryophytes as promising experimental models for heavy metal stress tolerance studies. Plants use several abiotic stress pathways which share common elements that are potential “nodes” for cross talks. Common elements/ molecules, which are likely to occur early in several stress response cascades in bryophytes seem to be the potential targets for heavy metal tolerance studies that can be worked out in future, at biochemical, protein and gene level.

Plants ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 71 ◽  
Author(s):  
Javaid Akhter Bhat ◽  
S. M. Shivaraj ◽  
Pritam Singh ◽  
Devanna B. Navadagi ◽  
Durgesh Kumar Tripathi ◽  
...  

Over the past few decades, heavy metal contamination in soil and water has increased due to anthropogenic activities. The higher exposure of crop plants to heavy metal stress reduces growth and yield, and affect the sustainability of agricultural production. In this regard, the use of silicon (Si) supplementation offers a promising prospect since numerous studies have reported the beneficial role of Si in mitigating stresses imposed by biotic as well as abiotic factors including heavy metal stress. The fundamental mechanisms involved in the Si-mediated heavy metal stress tolerance include reduction of metal ions in soil substrate, co-precipitation of toxic metals, metal-transport related gene regulation, chelation, stimulation of antioxidants, compartmentation of metal ions, and structural alterations in plants. Exogenous application of Si has been well documented to increase heavy metal tolerance in numerous plant species. The beneficial effects of Si are particularly evident in plants able to accumulate high levels of Si. Consequently, to enhance metal tolerance in plants, the inherent genetic potential for Si uptake should be improved. In the present review, we have discussed the potential role and mechanisms involved in the Si-mediated alleviation of metal toxicity as well as different approaches for enhancing Si-derived benefits in crop plants.


2020 ◽  
Author(s):  
Yang Yu ◽  
Zhaowei Teng ◽  
Zongmin Mou ◽  
Yan Lv ◽  
Tao Li ◽  
...  

Abstract Background: The high antioxidant capacity of melatonin contributing to heavy metal tolerance for plants and animals is widely studied, while researches on microorganisms especially in filamentous fungi are rare. One typical dark septate endophyte (DSE), Exophiala pisciphila, showed significant resistance to heavy metals.Results: In this study, exogenous melatonin was verified to reduce heavy metal damage via relieving oxidative stress, activating antioxidant systems, and decreasing heavy metal accumulation in E. pisciphila. Melatonin biosynthesis enzyme genes were upregulated under heavy metal stress. Furthermore, the overexpression of E. pisciphila TDC1 (EpTDC1) and E. pisciphila ASMT1 (EpASMT1) responsible for melatonin biosynthesis in Escherichia coli and Arabidopsis thaliana, enhanced heavy metal stress tolerance for the two organisms by lowering the oxidative stress and reducing the Cd accumulation in the whole plants, especially in the roots.Conclusions: Our results indicate that melatonin confers heavy metal resistance in E. pisciphila by lowering oxidative stress and heavy metal accumulation.


Silva Fennica ◽  
2021 ◽  
Vol 55 (3) ◽  
Author(s):  
Faujiah Ritonga ◽  
Jacob Ngatia ◽  
Run Song ◽  
Umar Farooq ◽  
Sonia Somadona ◽  
...  

Abiotic stress is one of the major factors in reducing plant growth, development, and yield production by interfering with various physiological, biochemical, and molecular functions. In particular, abiotic stress such as salt, low temperature, heat, drought, UV-radiation, elevated CO2, ozone, and heavy metals stress is the most frequent study in Sukaczev. is one of the most valuable tree species in East Asia facing abiotic stress during its life cycle. Using transgenic plants is a powerful tool to increase the abiotic stress tolerance. Generally, abiotic stress reduces leaves water content, plant height, fresh and dry weight, and enhances shed leaves as well. In the physiological aspect, salt, heavy metal, and osmotic stress disturbs seed germination, stomatal conductance, chlorophyll content, and photosynthesis. In the biochemical aspect, salt, drought, cold, heat, osmotic, UV-B radiation, and heavy metal stress increases the ROS production of cells, resulting in the enhancement of enzymatic antioxidant (SOD and POD) and non-enzymatic antioxidant (proline and AsA) to reduce the ROS accumulation. Meanwhile, upregulates various genes, as well as proteins to participate in abiotic stress tolerance. Based on recent studies, several transcription factors contribute to increasing abiotic stress tolerance in , including , and . These transcription factors bind to different cis-acting elements to upregulate abiotic stress-related genes, resulting in the enhancement of salt, drought, cold, heat, osmotic, UV-B radiation, and heavy metal tolerance. These genes along with phytohormones mitigate the abiotic stress. This review also highlights the candidate genes from another Betulacea family member that might be contributing to increasing abiotic stress tolerance.Betula platyphyllaBetula platyphyllaB. platyphyllaB. platyphyllaB. platyphyllaB. platyphyllaBplMYB46, BpMYB102, BpERF13, BpERF2, BpHOX2, BpHMG6, BpHSP9, BpUVR8, BpBZR1, BplERD15BpNACsB. platyphylla


Plants ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 155
Author(s):  
Anastasia Giannakoula ◽  
Ioannis Therios ◽  
Christos Chatzissavvidis

Photosynthetic changes and antioxidant activity to oxidative stress were evaluated in sour orange (Citrus aurantium L.) leaves subjected to lead (Pb), copper (Cu) and also Pb + Cu toxicity treatments, in order to elucidate the mechanisms involved in heavy metal tolerance. The simultaneous effect of Pb− and Cu on growth, concentration of malondialdehyde (MDA), hydrogen peroxide (H2O2), chlorophylls, flavonoids, carotenoids, phenolics, chlorophyll fluorescence and photosynthetic parameters were examined in leaves of Citrus aurantium L. plants. Exogenous application of Pb and Cu resulted in an increase in leaf H2O2 and lipid peroxidation (MDA). Toxicity symptoms of both Pb and Cu treated plants were stunted growth and decreased pigments concentration. Furthermore, photosynthetic activity of treated plants exhibited a significant decline. The inhibition of growth in Pb and Cu-treated plants was accompanied by oxidative stress, as indicated by the enhanced lipid peroxidation and the high H2O2 concentration. Furthermore, antioxidants in citrus plants after exposure to high Pb and Cu concentrations were significantly increased compared to control and low Pb and Cu treatments. In conclusion, this study indicates that Pb and Cu promote lipid peroxidation, disrupt membrane integrity, reduces growth and photosynthesis and inhibit mineral nutrition. Considering the potential for adverse human health effects associated with high concentrations of Pb and Cu contained in edible parts of citrus plants the study signals that it is important to conduct further research into the accessibility and uptake of the tested heavy metals in the soil and whether they pose risks to humans.


2018 ◽  
Vol 37 (4) ◽  
pp. 1423-1436 ◽  
Author(s):  
Shafaqat Ali ◽  
Muhammad Rizwan ◽  
Abbu Zaid ◽  
Muhammad Saleem Arif ◽  
Tahira Yasmeen ◽  
...  

2019 ◽  
Vol 43 (1) ◽  
pp. 73-83 ◽  
Author(s):  
Ksenija Jakovljevic ◽  
Sanja Djurovic ◽  
Mina Antusevic ◽  
Nevena Mihailovic ◽  
Uros Buzurovic ◽  
...  

Pontechium maculatum, a facultative metallophyte, was collected from four ultramafic localities in Serbia and analysed in terms of micro- and macroelement accumulation. The aim of the study was to reveal trace element profiles and differences in uptake and translocation of heavy metals in populations growing under heavy metal stress. The concentrations of major and trace elements in soil samples (Ca, Mg, Fe, Mn, Ni, Pb, Cr, Zn, Cu, Co, Cd) and in plant tissues (Fe, Mn, Ni, Pb, Cr, Zn, Cu, Co, Cd) are presented. The results of our analysis indicate that P. maculatum efficiently absorbs Zn and Cr, while for most of the other elements accumulation levels fit in the range of values obtained for several other species from ultramafic localities on the Balkan Peninsula.


2020 ◽  
Author(s):  
Meining Wang ◽  
Pei Tian ◽  
Min Gao ◽  
Miaomiao Li

Abstract Background: Festuca sinensis is a perennial grass of the genus Festuca, which has strong stress tolerance and high adaptability. F. sinensis normally symbiotic with Epichloë endophyte. In order to evaluate the possibility of F. sinensis-endophyte association as bioremediation grass in heavy metal polluted soils, the effects and mechanism of the F. sinensis-endophyte interaction under heavy metal stress was investigated. Results: The growth performance and physiology variations of F. sinensis with (E+) and without endophyte (E-) were evaluated after they were subjected to Zn2+ and Cd2+ treatments. The results showed that heavy metal treatments had significant effects on plants as the growth indices of plants under Zn2+ and Cd2+ treatments had significant differences compared with plants under control treatment (P<0.05). Zn2+ treatment had positive effects on plants whereas Cd2+ treatment had negative effects. The plants under Cd2+ treatment produced more lolitrem B (P<0.05). Endophyte increased host heavy metal stress tolerance by promoting host growth as the E+ plants had significantly higher plant height, tiller number, root length (P<0.05). Endophyte also promoted host Zn2+ ion absorbing and induced more endogenous hormone production (P<0.05). Conclusions: These results suggested that Epichloë regulated host growth and physiology to improve association tolerance to environmental conditions.


2021 ◽  
pp. 181-194
Author(s):  
Surbhi Dabral ◽  
Ajit Varma ◽  
Deepesh Bhatt ◽  
Manoj Nath

2015 ◽  
Vol 1130 ◽  
pp. 263-267 ◽  
Author(s):  
Hee Chan Jang ◽  
Marjorie Valix

In this study, the adaptation of A. thiooxidans to heavy metals leached from saprolitic Ni laterite ores was performed by gradual acclimatisation. The bacteria was cultivated in heavy metals (Ni, Co, Fe, Mg, Cr and Mn) with total concentrations of 2400 to 24000 ppm equivalent to total dissolution of 1 to 10% (w/v) pulp densities of the saprolitic Ni laterite ore. Adaptation evolution mapped from its tolerance index was found to be dependent on metal concentration, acid generation, and period of adaptation. Bio-stimulation of cell growth and acid production was promoted by heavy metal stress on the bacteria. Pre-established heavy metal tolerance of the bacteria improved the leaching rate in its early phase; 20% and 7% increase in Ni and Co metal recoveries were observed in using adapted bacteria. However heavy metal tolerance was also achieved by the bacteria during the leaching process, albeit delayed by a lag phase. These results confirm the robust nature and suitability of A. thiooxidans in direct biomining of Ni ores.


2021 ◽  
Vol 12 ◽  
Author(s):  
Ahmed H. El-Sappah ◽  
Rania G. Elbaiomy ◽  
Ahmed S. Elrys ◽  
Yu Wang ◽  
Yumin Zhu ◽  
...  

Metal tolerance proteins (MTPs) encompass plant membrane divalent cation transporters to specifically participate in heavy metal stress resistance and mineral acquisition. However, the molecular behaviors and biological functions of this family in Medicago truncatula are scarcely known. A total of 12 potential MTP candidate genes in the M. truncatula genome were successfully identified and analyzed for a phylogenetic relationship, chromosomal distributions, gene structures, docking analysis, gene ontology, and previous gene expression. M. truncatula MTPs (MtMTPs) were further classified into three major cation diffusion facilitator (CDFs) groups: Mn-CDFs, Zn-CDFs, and Fe/Zn-CDFs. The structural analysis of MtMTPs displayed high gene similarity within the same group where all of them have cation_efflux domain or ZT_dimer. Cis-acting element analysis suggested that various abiotic stresses and phytohormones could induce the most MtMTP gene transcripts. Among all MTPs, PF16916 is the specific domain, whereas GLY, ILE, LEU, MET, ALA, SER, THR, VAL, ASN, and PHE amino acids were predicted to be the binding residues in the ligand-binding site of all these proteins. RNA-seq and gene ontology analysis revealed the significant role of MTP genes in the growth and development of M. truncatula. MtMTP genes displayed differential responses in plant leaves, stems, and roots under five divalent heavy metals (Cd2+, Co2+, Mn2+, Zn2+, and Fe2+). Ten, seven, and nine MtMTPs responded to at least one metal ion treatment in the leaves, stems, and roots, respectively. Additionally, MtMTP1.1, MtMTP1.2, and MtMTP4 exhibited the highest expression responses in most heavy metal treatments. Our results presented a standpoint on the evolution of MTPs in M. truncatula. Overall, our study provides a novel insight into the evolution of the MTP gene family in M. truncatula and paves the way for additional functional characterization of this gene family.


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