scholarly journals Heavy Metals in Soils and the Remediation Potential of Bacteria Associated With the Plant Microbiome

2021 ◽  
Vol 9 ◽  
Author(s):  
Sarah González Henao ◽  
Thaura Ghneim-Herrera
Keyword(s):  
Heavy Metals ◽  
Plant Growth ◽  
Plant Species ◽  
Molecular Mechanisms ◽  
Bacterial Species ◽  
Growth And Yield ◽  
Depth Analysis ◽  
Cadmium And Lead ◽  
Assisted Phytoremediation ◽  
Plant Microbiome

High concentrations of non-essential heavy metals/metalloids (arsenic, cadmium, and lead) in soils and irrigation water represent a threat to the environment, food safety, and human and animal health. Microbial bioremediation has emerged as a promising strategy to reduce the concentration of heavy metals in the environment due to the demonstrated ability of microorganisms, especially bacteria, to sequester and transform these compounds. Although several bacterial strains have been reported to be capable of remediation of soils affected by heavy metals, published information has not been comprehensively analyzed to date to recommend the most efficient microbial resources for application in bioremediation or bacterial-assisted phytoremediation strategies that may help improve plant growth and yield in contaminated soils. In this study, we critically analyzed eighty-five research articles published over the past 15 years, focusing on bacteria-assisted remediation strategies for the non-essential heavy metals, arsenic, cadmium, and lead, and selected based on four criteria: i) The bacterial species studied are part of a plant microbiome, i.e., they interact closely with a plant species ii) these same bacterial species exhibit plant growth-promoting characteristics, iii) bacterial resistance to the metal(s) is expressed in terms of the Minimum Inhibitory Concentration (MIC), and iv) metal resistance is related to biochemical or molecular mechanisms. A total of sixty-two bacterial genera, comprising 424 bacterial species/strains associated with fifty plant species were included in our analysis. Our results showed a close relationship between the tolerance level exhibited by the bacteria and metal identity, with lower MIC values found for cadmium and lead, while resistance to arsenic was widespread and significantly higher. In-depth analysis of the most commonly evaluated genera, Agrobacterium, Bacillus, Klebsiella, Enterobacter, Microbacterium, Pseudomonas, Rhodococcus, and Mesorhizobium showed significantly different tolerance levels among them and highlighted the deployment of different biochemical and molecular mechanisms associated with plant growth promotion or with the presence of resistance genes located in the cad and ars operons. In particular, the genera Klebsiella and Enterobacter exhibited the highest levels of cadmium and lead tolerance, clearly supported by molecular and biochemical mechanisms; they were also able to mitigate plant growth inhibition under phytotoxic metal concentrations. These results position Klebsiella and Enterobacter as the best potential candidates for bioremediation and bacteria-assisted phytoremediation strategies in soils contaminated with arsenic, cadmium, and lead.

scholarly journals Evaluation of wild plants as lead (Pb) and cadmium (Cd) accumulators for phytoremediation of contaminated rice fields

2020 ◽  
Vol 21 (5) ◽  
Author(s):  
Nuril Hidayati ◽  
Dwi Setyo Rini
Keyword(s):  
Heavy Metals ◽  
Plant Growth ◽  
Plant Species ◽  
Biomass Production ◽  
Agricultural Land ◽  
Translocation Factor ◽  
Rice Fields ◽  
Wild Plants ◽  
Acorus Calamus ◽  
Cost Constraints

Abstract. Hidayati N, Rini DS. 2020. Assessment of plants as lead and cadmium accumulators for phytoremediation of contaminated rice field. Biodiversitas 21: 1928-1934. Heavy metals contamination in agricultural land becoming a serious problem since this causes declining in agriculture production and quality and thus food safety. Meanwhile, conventional efforts for remediation of the contaminated agricultural lands have not been widely implemented due to high-cost constraints. A low-cost technology that can be applied in contaminated sites is phytoremediation. This technique is based on the fact that plants have the ability to extract and accumulate heavy metals. This research aimed to study the potentials of some plant species as accumulators for phytoremediation in rice fields contaminated by heavy metals of lead (Pb) and cadmium (Cd). Six selected accumulator plant species, namely Colocasia sp., Ipomoea fistulosa Mart. ex Choisy, Eichhornia crassipes (Mart.) Solms, Hymenachne amplexicaulis (Rudge) Nees), Saccharum spontaneum L., and Acorus calamus L., were tested in in-situ field to identify the performance of the plants as accumulators for Pb and Cd. Parameters observed were plant growth and biomass production, and the accumulation of Pb and Cd in plants which is formulated as: bioconcentration factor (BCF) to indicate concentration ratio of metal in plant to soil, and translocation factor (TF) to indicate metal transportation ratio of shoot to root. The results showed that plants with the highest growth rate under contaminated conditions were E. crassipes, A. calamus, and H. amplexicaulis. The highest value of BCF for Pb accumulation was recorded in the shoot of H. amplexicaulis and E. crassipes and in the root of H. amplexicaulis and A. calamus, whereas the highest value of TF for Pb was observed in E. crassipes, S. spontaneum, and H. amplexicaulis. Meanwhile, the highest value of BCF for Cd in the shoot and in the root was observed in Colocasia sp and H. amplexicaulis whereas the highest value of TF for Cd was identified in A calamus and Colocasia sp. With regards to the performance of plant growth, biomass production, and accumulation of Pb and Cd, it is suggested that three plant species, namely E. crassipes, A. calamus, and H. amplexicaulis are considered as potential Pb and Cd accumulators for phytoremediation of contaminated rice fields. Our findings suggest that some plants can produce high biomass and absorb high contaminants while other plants cannot, implying that plants respond differently to different environmental conditions. Therefore continuous research is required to obtain the best plant species for phytoremediation.

Understanding the molecular mechanisms for the enhanced phytoremediation of heavy metals through plant growth promoting rhizobacteria: A review

2020 ◽  
Vol 254 ◽  
pp. 109779 ◽  
Author(s):  
Srinivas Ravi Manoj ◽  
Chinnannan Karthik ◽  
Krishna Kadirvelu ◽  
Padikasan Indra Arulselvi ◽  
Thangavel Shanmugasundaram ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Plant Growth ◽  
Molecular Mechanisms ◽  
Plant Growth Promoting Rhizobacteria ◽  
Plant Growth Promoting ◽  
Growth Promoting

Phosphate Uptake and Transport in Plants: An Elaborate Regulatory System

2021 ◽  
Author(s):  
Yan Wang ◽  
Fei Wang ◽  
Hong Lu ◽  
Yu Liu ◽  
Chuanzao Mao
Keyword(s):  
Plant Growth ◽  
Molecular Mechanisms ◽  
Protein Localization ◽  
Regulatory System ◽  
Growth And Yield ◽  
Limiting Factor ◽  
P Efficiency ◽  
Phosphate Transporters ◽  
Protein Levels

Abstract Phosphorus (P) is an essential macronutrient for plant growth and development. Low phosphate (Pi) availability is a limiting factor for plant growth and yield. To cope with a complex and changing environment, plants have evolved elaborate mechanisms for regulating Pi uptake and use. Recently, the molecular mechanisms of plant Pi signaling have become clearer. Plants absorb Pi from the soil through their roots and transfer Pi to various organs or tissues through phosphate transporters, which are precisely controlled at the transcript and protein levels. Here, we summarize the recent progress on the molecular regulatory mechanism of phosphate transporters in Arabidopsis and rice, including the characterization of functional transporters, regulation of transcript levels, protein localization, and turnover of phosphate transporters. A more in-depth understanding of plant adaptation to a changing Pi environment will facilitate the genetic improvement of plant P efficiency.

scholarly journals Physiological, Transcriptomic Investigation on the Tea Plant Growth and Yield Motivation by Chitosan Oligosaccharides

Horticulturae ◽  
2022 ◽  
Vol 8 (1) ◽  
pp. 68
Author(s):  
Lina Ou ◽  
Qiuqiu Zhang ◽  
Dezhong Ji ◽  
Yingying Li ◽  
Xia Zhou ◽  
...  
Keyword(s):  
Plant Growth ◽  
Molecular Mechanisms ◽  
Academic Support ◽  
Soluble Sugar ◽  
Tea Plant ◽  
Growth And Yield ◽  
Practical Application ◽  
Chitosan Oligosaccharides ◽  
Fundamental Information ◽  
Tea Plants

Chitosan oligosaccharides (COS) has been abundantly studied for its application on regulating plant growth of many horticultural and agricultural crops. We presented here the effect of COS on tea plant growth and yield by physiological and transcriptomic checking. The results showed that COS treatment can enhance the antioxidant activity of superoxide dismutase (SOD) and peroxidase (POD) and increase the content of chlorophyll and soluble sugar in tea plants. The field trail results show that COS treatment can increase tea buds’ density by 13.81–23.16%, the weight of 100 buds by 15.94–18.15%, and the yield by 14.22–21.08%. Transcriptome analysis found 5409 COS-responsive differentially expressed genes (DEGs), including 3149 up-regulated and 2260 down-regulated genes, and concluded the possible metabolism pathway that responsible for COS promoting tea plant growth. Our results provided fundamental information for better understanding the molecular mechanisms for COS’s acting on tea plant growth and yield promotion and offer academic support for its practical application in tea plant.

Role of Plant Growth Promoting Rhizosphere (PGPR) on Molecular Mechanisms Transporters Under Heavy Metal Stress

2020 ◽  
pp. 71-84
Keyword(s):  
Heavy Metals ◽  
Plant Growth ◽  
Molecular Mechanisms ◽  
Heavy Metal Stress ◽  
Molecular Transporters ◽  
Removal Of Heavy Metals ◽  
Plant Growth Promoting ◽  
Growth Promoting ◽  
Soil And Water

In this chapter, the authors discuss the molecular mechanisms transporters used for the removal of heavy metals contaminants from soil and water. The bioremediation method used for soil remediation render the land useless as a medium for plant growth as they also remove other contaminants that harm microbes and maintaining soil fertility with the help generating heat shok protein and metallothiones and also molecular transporters.

Effects of Cadmium and Lead on Plant Growth and Content of Heavy Metals in Arugula Cultivated in Nutritive Solution

2013 ◽  
Vol 44 (5) ◽  
pp. 952-961 ◽  
Author(s):  
Marcele G. Cannata ◽  
Ruy Carvalho ◽  
Alexandre C. Bertoli ◽  
Amanda S. Augusto ◽  
Ana Rosa R. Bastos ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Plant Growth ◽  
Nutritive Solution ◽  
Cadmium And Lead

scholarly journals Metabolic activities and molecular investigations of the ameliorative impact of some growth biostimulators on chilling-stressed coriander (Coriandrum sativum L.) plant

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Raifa A. Hassanein ◽  
Omaima S. Hussein ◽  
Amal F. Abdelkader ◽  
Iman A. Farag ◽  
Yousra E. Hassan ◽  
...  
Keyword(s):  
Humic Acid ◽  
Plant Growth ◽  
Yield Components ◽  
Molecular Mechanisms ◽  
Growth Parameters ◽  
Chilling Stress ◽  
Growth Yield ◽  
Growth And Yield ◽  
Whole Plant ◽  
Metabolic Activities

Abstract Background Priming of seed prior chilling is regarded as one of the methods to promote seeds germination, whole plant growth, and yield components. The application of biostimulants was reported as beneficial for protecting many plants from biotic or abiotic stresses. Their value was as important to be involved in improving the growth parameters of plants. Also, they were practiced in the regulation of various metabolic pathways to enhance acclimation and tolerance in coriander against chilling stress. To our knowledge, little is deciphered about the molecular mechanisms underpinning the ameliorative impact of biostimulants in the context of understanding the link and overlap between improved morphological characters, induced metabolic processes, and upregulated gene expression. In this study, the ameliorative effect(s) of potassium silicate, HA, and gamma radiation on acclimation of coriander to tolerate chilling stress was evaluated by integrating the data of growth, yield, physiological and molecular aspects. Results Plant growth, yield components, and metabolic activities were generally diminished in chilling-stressed coriander plants. On the other hand, levels of ABA and soluble sugars were increased. Alleviation treatment by humic acid, followed by silicate and gamma irradiation, has notably promoted plant growth parameters and yield components in chilling-stressed coriander plants. This improvement was concomitant with a significant increase in phytohormones, photosynthetic pigments, carbohydrate contents, antioxidants defense system, and induction of large subunit of RuBisCO enzyme production. The assembly of Toc complex subunits was maintained, and even their expression was stimulated (especially Toc75 and Toc 34) upon alleviation of the chilling stress by applied biostimulators. Collectively, humic acid was the best the element to alleviate the adverse effects of chilling stress on growth and productivity of coriander. Conclusions It could be suggested that the inducing effect of the pretreatments on hormonal balance triggered an increase in IAA + GA3/ABA hormonal ratio. This ratio could be linked and engaged with the protection of cellular metabolic activities from chilling injury against the whole plant life cycle. Therefore, it was speculated that seed priming in humic acid is a powerful technique that can benefit the chilled along with non-chilled plants and sustain the economic importance of coriander plant productivity.

scholarly journals Effects of Heavy Metals on Plant Growth and Metal Accumulation in Moringa Plant.

2020 ◽  
pp. 126-137
Author(s):  
Waheed Yaseen ◽  
Bakhtawar Sajjad ◽  
Iqra Azam ◽  
Humayun Ajaz
Keyword(s):  
Heavy Metals ◽  
Plant Growth ◽  
Moringa Oleifera ◽  
Metal Accumulation ◽  
Growth And Yield ◽  
Physical Parameters ◽  
Distilled Water ◽  
Optimum Conditions ◽  
Aqua Regia ◽  
Toxicity Level

Moringa oleifera sprung in soil contaminated with Lead and Magnesium. Stress of heavy metals of different strength was applied in each replicate. Physical parameters are necrosis, chlorosis, and height of plant included in this research. The sample Leaves, roots and stems are collected from each replicate after a week, washed, dried weighed, crushed, digested with Aqua Regia and at the end filtered. The extract was diluted to a specific extent with distilled water and quantitatively measured with Atomic Absorption Spectrophotometer. The data collected was statistically analyzed. Measured the Toxicity level and optimum conditions for plant growth and yield was calculated from the data collected. .

scholarly journals Zinc Hyperaccumulation in Plants: A Review

Plants ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 562 ◽  
Author(s):  
Habiba Balafrej ◽  
Didier Bogusz ◽  
Zine-El Abidine Triqui ◽  
Abdelkarim Guedira ◽  
Najib Bendaou ◽  
...  
Keyword(s):  
Plant Growth ◽  
Plant Species ◽  
Human Activities ◽  
Growth And Development ◽  
Molecular Mechanisms ◽  
Plant Growth And Development ◽  
Physiological Disorders ◽  
Physiological And Biochemical ◽  
Excess Zinc

Zinc is an essential microelement involved in many aspects of plant growth and development. Abnormal zinc amounts, mostly due to human activities, can be toxic to flora, fauna, and humans. In plants, excess zinc causes morphological, biochemical, and physiological disorders. Some plants have the ability to resist and even accumulate zinc in their tissues. To date, 28 plant species have been described as zinc hyperaccumulators. These plants display several morphological, physiological, and biochemical adaptations resulting from the activation of molecular Zn hyperaccumulation mechanisms. These adaptations can be varied between species and within populations. In this review, we describe the physiological and biochemical as well as molecular mechanisms involved in zinc hyperaccumulation in plants.

scholarly journals Molecular Interaction and Evolution of Jasmonate Signaling With Transport and Detoxification of Heavy Metals and Metalloids in Plants

2021 ◽  
Vol 12 ◽  
Author(s):  
Xuan Chen ◽  
Wei Jiang ◽  
Tao Tong ◽  
Guang Chen ◽  
Fanrong Zeng ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Plant Species ◽  
Toxic Elements ◽  
Molecular Mechanisms ◽  
Gene Families ◽  
Green Plant ◽  
Mitigation Strategies ◽  
Toxic Heavy Metals ◽  
Metals And Metalloids ◽  
Heavy Metals And Metalloids

An increase in environmental pollution resulting from toxic heavy metals and metalloids [e.g., cadmium (Cd), arsenic (As), and lead (Pb)] causes serious health risks to humans and animals. Mitigation strategies need to be developed to reduce the accumulation of the toxic elements in plant-derived foods. Natural and genetically-engineered plants with hyper-tolerant and hyper-accumulating capacity of toxic minerals are valuable for phytoremediation. However, the molecular mechanisms of detoxification and accumulation in plants have only been demonstrated in very few plant species such as Arabidopsis and rice. Here, we review the physiological and molecular aspects of jasmonic acid and the jasmonate derivatives (JAs) in response to toxic heavy metals and metalloids. Jasmonates have been identified in, limiting the accumulation and enhancing the tolerance to the toxic elements, by coordinating the ion transport system, the activity of antioxidant enzymes, and the chelating capacity in plants. We also propose the potential involvement of Ca2+ signaling in the stress-induced production of jasmonates. Comparative transcriptomics analyses using the public datasets reveal the key gene families involved in the JA-responsive routes. Furthermore, we show that JAs may function as a fundamental phytohormone that protects plants from heavy metals and metalloids as demonstrated by the evolutionary conservation and diversity of these gene families in a large number of species of the major green plant lineages. Using ATP-Binding Cassette G (ABCG) transporter subfamily of six representative green plant species, we propose that JA transporters in Subgroup 4 of ABCGs may also have roles in heavy metal detoxification. Our paper may provide guidance toward the selection and development of suitable plant and crop species that are tolerant to toxic heavy metals and metalloids.

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