Plant Peroxidases Research Articles

Synergism between Streptomyces viridosporus HH1 and Rhizophagus irregularis Effectively Induces Defense Responses to Fusarium Wilt of Pea and Improves Plant Growth and Yield.

Fusarium wilt is a detrimental disease of pea crop, resulting in severe damage and a reduction in its yield. Developing synergistically enhanced bioagents for disease management and growth promotion is pivotal for food safety, security, and sustainability. In this study, biocontrol potential of treating pea plants with Streptomyces viridosporus HH1 and/or their colonization with Rhizophagus irregularis against infection with Fusarium wilt was investigated. Impacts on the expression profiles of defense-related genes, biochemical, and ultrastructural levels, as well as the growth and yield of pea plants in response to these treatments, were also investigated. Data obtained indicated the antifungal activity of S. viridosporus HH1 against F. oxysporum f.sp. pisi in vitro. Furthermore, the GC-MS analysis revealed production of different bioactive compounds by S. viridosporus HH1, including 2,3-butanediol, thioglycolic acid, and phthalic acid. The results from the greenhouse experiment exhibited a synergistic biocontrol activity, resulting in a 77% reduction in disease severity in pea plants treated with S. viridosporus HH1 and colonized with R. irregularis. In this regard, this dual treatment overexpressed the responsive factor JERF3 (5.6-fold) and the defense-related genes β-1,3-glucanase (8.2-fold) and the pathogenesis-related protein 1 (14.5-fold), enhanced the total phenolic content (99.5%), induced the antioxidant activity of peroxidase (64.3%) and polyphenol oxidase (31.6%) enzymes in pea plants, reduced the antioxidant stress, and improved their hypersensitivity at the ultrastructural level in response to the Fusarium wilt pathogen. Moreover, a synergistic growth-promoting effect was also recorded in pea plants in response to this dual treatment. In this regard, due to this dual treatment, elevated levels of photosynthetic pigments and improved growth parameters were observed in pea leaves, leading to an increment in the yield (113%). In addition, application of S. viridosporus enhanced the colonization levels with R. irregularis in pea roots. Based on the obtained data, we can conclude that treating pea plants with S. viridosporus HH1 and colonization with R. irregularis have synergistic biocontrol activity and growth-promoting effects on pea plants against Fusarium wilt. Despite its eco-safety and effectiveness, a field evaluation of this treatment before a use recommendation is quite necessary.

Construction of the SHP-GLOX lignin regulation system and its application in rice straw

BackgroundThere is great productivity of rice(Oryza sativa L. spp. japonica) straw in China, which is a potential source of biomass for biofuel and forage. However, the high levels of lignins in rice straw limited its usage and induced the formation of agricultural waste. In order to modify the lignins contents to improve biofuel production and forage digestibility, we selected Soybean hull peroxidase (SHP) and Glyoxal oxidase (GLOX) as candidate genes to improve quality of rice straw. SHP, a class III plant peroxidase, is derived from multiple sources. It has several advantages, such as high resistance to heat, high stability under acidic and alkaline conditions, and a broad substrate range. SHP is speculated to be useful for lignin degradation. Glyoxal oxidase (GLOX) is an extracellular oxidase that can oxidize glyoxal and methylglyoxal in the extracellular medium to generate H2O2.ResultsIn the present study, the SHP and GLOX genes in pCAMBIA3301-glycine-rich protein (GRP)-SHP-GLOX, designated the K167 vector, were optimized and introduced into rice embryos using Agrobacterium-mediated transformation. Positive transgenic rice embryos were examined using molecular, physiological, biochemical and fermentation tests. The outcomes suggested that SHP degraded lignin effectively.ConclusionsThis research has created a rice breeding material with normal growth and yield but stalks that are more amenable to degradation in the later stage for use in breeding rice varieties whose stalks are easily used for energy. Our results will improve the industrial and commercial applications of rice straw.

Interaction of ascorbic acid and 24- epibrassinolide on the level of protein and activity of antioxidant enzymes of catalase and peroxidase on jiropt bean plants (Phaseolus acutifolius) under salinity condition

A group of strong antioxidants, such as ascorbic acid and 24- epibrassinolide have significant environmental effects on plant growth and development. They can cause an increase in plant tolerance to environmental stresses. This research is performed to study the interaction of ascorbic acid and 24- epibrassinolide on the amount of protein and activity of antioxidant catalase enzymes and peroxidase in jiropt bean plants (Phaseolus acutifolius) under salinity. The experiments were performed completely as randomized factorial designs with three concentration of NaCl (0,5,10 %),three concentration of ascorbic acid (0,10,15µm) and Three concentration of 24- epibrassinolide(0,5,10 µm)each one with three replications in greenhouse controlled conditions.The results showed that salinity has a significant and cumulative effect on the protein content and activity of antioxidant enzymes of catalase and peroxidase. The destructive Ascorbic acid-modified effects salt and increases protein content and activity of catalase and peroxidase enzymes, 24-epibrassinolide modified salt effects and caused more increase in protein content and activity of antioxidant enzymes compared to salt treatment, the interaction between ascorbic acid and 24- epibrassinolide on modifying the salt effects were observed in bean plants.

Crataegus oxyacantha Extract as a Biostimulant to Enhance Tolerance to Salinity in Tomato Plants.

Salinity is a severe abiotic problem that has harmful impacts on agriculture. Recently, biostimulants were defined as bioprotectant materials that promote plant growth and improve productivity under various stress conditions. In this study, we investigated the effect of Crataegus oxyacantha extract as a biostimulant on tomato plants (Solanum lycopersicum) grown under salt stress. Concentrations of 20 mg/L, 30 mg/L, and 70 mg/L of C. oxyacantha extract were applied to tomato plants that were grown under salt stress. The results indicated that plants that were treated with C. oxyacantha extract had a higher ability to tolerate salt stress, as demonstrated by a significant (p < 0.05) increase in plant growth and photosynthetic pigment contents, in addition to a significant increase in tomato soluble sugars and amino acids compared to the control plants. In the stressed tomato plants, malondialdehyde increased and then decreased significantly with the different concentrations of C. oxyacantha extract. Furthermore, there was a significant improvement in the antioxidant enzyme activities of superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione S-transferase (GST), and glutathione reductase (GR) in the stressed plants, especially after treatment with 70 mg/L of the extract. Overall, our results suggest that C. oxyacantha extract could be a promising biostimulant for treating tomato plants under salinity stress.

Zinc Supplementation Enhances Glutathione-Mediated Antioxidant Defense and Glyoxalase Systems to Conferring Salt Tolerance in Soybean (Glycine max L.)

In this study, the role of zinc (Zn) in salt-affected soybean (Glycine max L.) was scrutinized by exposing plants to salt stress (150 mM NaCl) alone and in combination with exogenous Zn (priming and/or foliar spray with 1 mM ZnSO4.7H2O). Salt stress decreased plant growth and caused the destruction of chlorophyll and carotenoids. It also disrupted physiological processes and antioxidant defenses, resulting in an oxidative burst. The levels of the toxic metabolite methylglyoxal (MG) rose substantially under salinity. Salinity resulted in a high accumulation of Na+ and decreased K+ which decreased the K+/Na+ ratio. Zn supplementation decreased ion toxicity and improved ion homeostasis in soybean plants. Zn increased glutathione (GSH) levels, decreased glutathione disulfide levels, and increased their ratio in salt-treated soybean plants compared to salt-treated plants without Zn addition. Zn supplementation also upregulated the activities of the glutathione-dependent enzymes glutathione reductase, dehydroascorbate reductase, glutathione peroxidase, and glutathione S-transferase in salt-stressed plants. The enhanced GSH pool and increased activity of GSH-dependent enzymes decreased oxidative damage, as indicated by the reduced levels of H2O2 and malondialdehyde and lower electrolyte leakage. The increased GSH level and high activity of glyoxalase I and glyoxalase II conferred by Zn under salt stress helped to scavenge methylglyoxal. The restoration of photosynthetic pigment levels and increased proline accumulation, together with the recovery of leaf relative water content, were further signs of salt stress recovery and tolerance conferred by Zn supplementation. Our results showed that the antioxidant defense, glyoxalase system and some other physiological parameters were improved by Zn supplementation which contributed to mitigating the effects of salt stress in soybean.

Salicornia europaea L. Functional Traits Indicate Its Optimum Growth.

Salicornia europaea L. grows in areas periodically flooded by salty or brackish water. It has potential economic value, because it can be used as food, forage, or biofuel, and has potential in pharmaceuticals and cosmetics. Increasing interest in S. europaea is due to its extreme salt tolerance and well growth in marginal saline soils. However, the variation in its functional traits in response to environmental conditions is still poorly studied. There are still questions regarding the optimal level of salinity for different traits. Therefore, we worked to address the question if S. europaea traits from different scales are controlled by salinity level. Based on performed pot experiment, we found that almost all traits are salinity dependent but affected in different ways. We demonstrated that morphological, biomass, and anatomical properties indicate optimum growth between 200 and 400 mM NaCl and growth limitations at 0, 800, and 1000 mM NaCl. Moreover, we found the most affected traits which include photosynthetic pigments and protein content, plant surface area, peroxidase activity, and anatomic traits related to cell shape. Our results significantly expanded the knowledge about S. europaea functional traits variation in response to salinity, which can be important for discovering regulating processes and for possible future agricultural applications.

Enhanced brassinosteroid signaling via the overexpression of SlBRI1 positively regulates the chilling stress tolerance of tomato

Brassinosteroids (BRs) regulate plant development and response to stress. BRASSINOSTEROID INSENSITIVE 1 (BRI1) is a BR receptor that activates BR signaling. Although the function of the tomato BR receptor SlBRI1 in regulating growth and drought resistance has been examined, that of SlBRI1 in cold tolerance is unclear. This study indicated that the expression of SlBRI1 in tomato was rapidly induced and reached its highest level at 3 h under chilling treatment and then decreased. The overexpression of SlBRI1 displayed low relative electrolyte leakage, malondialdehyde content, and reactive oxygen species (ROS) accumulation under chilling stress. The proline content and activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) in SlBRI1OE plants were higher than those in the wild-type (WT) plants after chilling stress. The transcript abundances of five cold-responsive genes were higher in SlBRI1OE plants than in WT plants during chilling stress. RNA sequence analysis showed that the expression of the majority of genes encoding photosystem I and II were downregulated. The degree of suppression in SlBRI1OE plants was weaker than that in WT plants. Additionally, the Pn and Fv/Fm of SlBRI1OE plants were significantly higher than those of WT plants under chilling stress. We identified several genes encoding key enzymes in BRs; indole acetic acid (IAA), gibberellin (GA), and abscisic acid (ABA) biosynthesis or signaling were upregulated or downregulated during chilling stress. Chilling stress decreased the BRs and GA3 content, and increased IAA and ABA content. The contents were lower or higher in SlBRI1OE than in WT plants. Furthermore, chilling stress regulated the expression levels of 43 transcription factors. The expression of seven cold-regulated protein genes was higher or lower in SlBRI1OE plants than in WT plants under chilling stress. These results suggest that SlBRI1 positively regulates chilling tolerance mainly through ICE1–CBF–COR pathway in tomato.

Phytoremediation potential of Bermuda grass (Cynodon dactylon (L.) pers.) in soils co-contaminated with polycyclic aromatic hydrocarbons and cadmium

Soils co-contaminated with polycyclic aromatic hydrocarbons (PAHs) and cadmium (Cd) have serious environmental impacts and are highly toxic to humans and ecosystems. Phytoremediation is an effective biotechnology for the remediation and restoration of PAH- and Cd-polluted soils. Pot experiments were conducted to investigate the individual and combined effects of PAHs (1238.62 mg kg−1) and Cd (23.1 mg kg−1) on the phytoremediation potential of Bermuda grass grown in contaminated soils. Bermuda grass exhibited a significant decrease in plant growth rate, leaf pigment content, root activity, plant height and biomass and a remarkable increase in malondialdehyde content and electrolyte leakage when grown in PAH- and Cd-contaminated soils compared with grass grown in uncontaminated soils. The activity of soil enzymes, including urease, alkaline phosphatase, sucrose, and fluorescein diacetate hydrolysis, were reduced in soil with PAH and Cd stress. Furthermore, the toxicity of combined PAHs and Cd on Bermuda grass growth and soil enzyme activity was much higher than that of PAH or Cd stress alone, suggesting a synergistic effect of PAHs and Cd on cytotoxicity. To scavenge redundant reactive oxygen species and avoid oxidative damage, Bermuda grass increased plant catalase, superoxide dismutase, and peroxidase activity and soluble sugar and proline content. The bioconcentration factor of Cd in Bermuda grass grown under Cd alone and combined PAH and Cd exposure was greater than 1 for both, suggesting that Bermuda grass has a high Cd accumulation ability. Under PAH alone and combined PAH and Cd exposure conditions, a higher PAH removal rate (41.5–56.8%) was observed in soils planted with Bermuda grass than in unplanted soils (24.8–29.8%), indicating that Bermuda grass has a great ability to degrade PAHs. Bermuda grass showed great phytoremediation potential for the degradation of PAHs and phytoextraction of Cd in co-contaminated soils.

Glutathione Peroxidases in Plants: Innumerable Role in Abiotic Stress Tolerance and Plant Development

Glutathione Peroxidases in Plants: Innumerable Role in Abiotic Stress Tolerance and Plant Development

Identification of Fe(iii)–OH species as a catalytic intermediate in plant peroxidases at high H2O2 concentration

The structure for compound III formed after exposure of plant heme peroxidases to excess H2O2 seems to be a hydroxylated form, providing new evidence for understanding the structural basis of the substrate-induced suicidal behavior of these enzymes.

Systematic analysis of the Serine/Arginine-Rich Protein Splicing Factors (SRs) and focus on salt tolerance of PtSC27 in Populus trichocarpa

Serine/Arginine-Rich Protein Splicing Factors (SRs) are indispensable splicing factors, which play significant roles in spliceosome assembly, splicing regulation and regulation of plant stress. However, a comprehensive analysis and function research of SRs in the woody plant is still lacking. In this report, we conducted the identification and comprehensive analysis of the 71 SRs in poplar and three other dicots, including basic characterization, phylogenetic, conserved motifs, gene duplication, promoter and splice isoform of these genes. Based on the publicly available transcriptome data, expression pattern of SRs in poplar under low temperature, high temperature, drought and salt stress were further analyzed. Subsequently, a key candidate gene PtSC27 that responded to salt stress was screened. More importantly, overexpression of PtSC27 increased plant survival rate under salt stress, and enhanced salt tolerance by regulating malondialdehyde (MDA) content, peroxidase (POD) and catalase (CAT) enzyme activities in transgenic plants. Meanwhile, overexpression of PtSC27 made transgenic plants insensitive to exogenous ABA and improved the expression of some ABA signal-related genes under salt stress. Overall, our studies lay a foundation for understanding the structure and function of SRs in the poplar and provide useful gene resources for breeding through genetic engineering.

Evaluating the efficacy of Trichoderma harzianum and Bacillus thuringiensis on induce the plant growth and resistance of local variety patchouli under covered and uncovered seedlings methods

To increase plant resistance from an early age, it is necessary to introduce biological control agents from groups of fungi and bacteria. This study aims to determine the effect of Trichoderma harziaunum and Bacillus thuringiensis Aceh isolates in increasing the superiority of Aceh patchouli plants that are resistant to pests and plant diseases. The study used non-factorial RAL method with cover and uncovered seedling methods. Both series were treated with the same biological control agent, the control without any treatment, the treatment of T. harzianum and B. thuringiensis while the observations were made when the seedling covered was opened. Observations included plant morphological characters, plant growth development and peroxidase enzymes. The results showed that morphologically the original patchouli growing in Lhoong district had similar morphological characters to the Lhokseumawe variety. The application of biological control agents of the T. harzianum and B. thuringiensis groups was more effective in increasing plant growth in the closed seedling treatment compared to the uncovered seedling. T. harzianum gave the best effect at a dose range of 1-1.5 while B. thuringensis showed a better effect at a concentration of 10-15 ml. Both treatments increased the growth of patchouli seedlings as indicated by the better plant height and number of shoots. Furthermore, higher peroxidation enzymes were found in the closed seedling treatment with 1.5 g T harzianum and 15 ml B. thuringiensis. The high peroxidase enzyme as an indicator of the more resistant plants have been induced to pests and diseases. From the screen house experiment, T. harzianum and B. thuringiensis were more efficient in inducing plant growth and disease resistance of local varieties of patchouli using the closed seedling method.

The activity of enzymes can be modified by homeopathic dilutions of their effectors

Introduction: The fungal and bacterial materials are very useful for testing the influence of low and very low doses of low molecular phenolic effectors on enzymatic system of phenoloxidases when they are incubated together in the reaction space.&#x0D; Aim: Searching for the model useful biological systems to study the action of diluted low molecular substances on living organisms, which is based on common physical and biochemical analytical procedures.&#x0D; Methods: The fungal and actinomycetal bacterial materials from laboratory cultures as a source of common phenoloxidases, laccase, peroxidase and O-demethylase as well as the pure plant peroxidase were used in experiments described earlier [1-5]. Subsequent dilutions of low molecular phenolic metabolites, appropriate for studied enzymatic systems, prepared in 75% ethanol in the proportion of 1:100 (centesimal) and dynamized by shaking in accordance with homeopathic procedures were prepared in our laboratory. During experiments with bacterial and fungal materials and a pure plant peroxidase, which were incubated together with subsequent dilutions of proper phenolic effector, different analytic methods were used including a gel (PAGE) [4] and capillary (MEKCE) electrophoresis [5], spectral and colorimetric methods [1,2,3] as well as the electron microscopy [5].&#x0D; Results: In the light of presented data [1-5], the incubation of biological material with diluted phenolic effectors induces various effects on tested enzyme activity. It changed in sinusoidal manner with an gradual growth of dilution rate of tested effectors, which was distinctly visible on the diagram when the number of dilutions was localized on abscissa and biological activity on the ordinate. &#x0D; Exemplary results of the chosen experiments will be presented. For tested enzymes: laccase, peroxidase and O-demethylase, the distance between maximal points of enzymatic activity, shown on a sine curve, repeats more often every 10 subsequent centesimal dilutions. Along with the extension of incubation period the displacement of maximal and minimal points on curve were noticed, which revealed a dynamic aspect of studied phenomenon. &#x0D; Conclusions: Fungal and bacterial cells seem to be a very convenient material for studying the action of diluted metabolites on enzymatic systems because their popular presence in environment. Results of all experiments confirmed the same nature of the mentioned observations. Because other authors had similar conclusion concerning human [6,7] and plant materials [8,9], the described relations seem to be common in natural world. It could also be stressed that the therapeutic effect of homeopathic remedies could be based on the mechanism described above and it is highly probable that it leads to a normalisation of disturbed enzyme systems in the living organisms.

"Breeding on Mountains" Resulted in the Reorganization of Endophytic Fungi in Asexually Propagated Plants (Ligusticum chuanxiong Hort.).

“Breeding on mountains, cultivation in dam areas” is a unique propagation method for the vegetatively propagated plant Ligusticum chuanxiong, including two transplants between the mountain and the dam area. It is well known that the environment can influence the endophytic community structure of plants. However, the change of host endophytic flora caused by transplanting in different places and its influence on asexual reproduction are still poorly understood. We carried out three cycles of cultivation experiments on L. chuanxiong and collected stem nodes (LZ), immature rhizomes (PX), medicinal rhizomes (CX), and rhizosphere. High-throughput sequencing was performed to analyze the endophytic fungi in all samples. We observed that the diversity and richness of endophytic fungi in L. chuanxiong increased as a result of transplanting cultivation from dam areas to mountains. Local transplantation caused minor changes in the endophytic fungus structure of L. chuanxiong, while remote transplantation caused significant changes. Compared with LZ after breeding in the dam area, the LZ after breeding on mountains has more abundant Gibberella, Phoma, Pericona, Paraphoma, and Neocosmospora. The regular pattern of the relative abundance of endophytic fungi is consistent with that of the fungus in the soil, while there are also some cases that the relative abundance of endophytic fungi is the opposite of that of soil fungi. In addition, there is a significant correlation among certain kinds of endophytic fungi whether in the soil or the plants. We have isolated more gibberellin-producing and auxin-producing fungi in the LZ cultivated in the mountains than that in the LZ cultivated in the dam area. The results of pot experiments showed that the three fungi isolated from LZ cultivated in mountainous areas can promote the development of shoots, stem nodes, and internodes of LZ, and increase the activity of plant peroxidase, catalase, phenylalanine ammonia lyase, and other enzymes. We can conclude that transplantation leads to the recombination of the host endophytic fungus, the more significant the difference in the environment is, the greater the reorganization caused by transplanting. Reorganization is determined by the soil environment, hosts, and the interaction of microorganisms. Remote transplantation is a crucial opportunity to reshuffle the micro-ecological structure of the asexual reproduction of plants, and regulate the growth, development, and resistance of plants, and prevent germplasm degradation caused by asexual reproduction.

Production and Purification of Peroxidase from Tissue Cultures of Cauliflower (Brassica oleracea L. var. Botrytis)

The Plant peroxidases are remarkable enzymes due to their widespread use in industry. These enzymes, which are capable of catalyzing the oxidation of various organic and inorganic substrates, have been used in clinical diagnosis, detoxification reactions and organic synthesis. In this study, in vitro production and purification of peroxidase enzyme from cauliflower plant was proposed. Firstly, sterile seedlings were obtained from MS/B5 nutrient medium without growth regulator from cauliflower seeds and calluses from medium containing 0.5 mg / L 2.4-D. Callus and seedlings were powdered with liquid nitrogen and then homogenized. Peroxidase enzymes were purified from these homogenates using affinity technique. SDS-PAGE electrophoresis was performed to determine the molecular weight of the purified enzymes and single bands was observed at approximately 46 kDa. In addition, KM and Vmax values of the callus peroxidase enzyme were determined for guaiacol, pyrogallol and H2O2 substrates.

Effect of dielectric barrier discharge (DBD) plasma on the activity and structural changes of horseradish peroxidase

As an emerging nonthermal technology, cold plasma has been used to inactivate endogenous enzymes that are responsible for enzymatic browning reaction of fruits and vegetables. This study aimed to investigate the inactivation effect of dielectric barrier discharge (DBD) plasma on horseradish peroxidase (HRP), a typical plant peroxidase. The results showed that DBD plasma caused inactivation of HRP in a time-and discharge power-dependent manner. The HRP activity decreased by 32.5, 50.6, 65.5, and 75.4%, respectively, after 2, 4, 6, and 8 min of exposure to DBD plasma at 57.6 W. The efficacy of DBD plasma for HRP inactivation was enhanced on increasing the discharge power from 6.0 to 57.6 W. Intrinsic fluorescence spectra showed that DBD plasma induced obvious structural changes in HRP. DBD plasma also caused fragmentation and carbonylation of HRP as well as the oxidative degradation of heme, which might be due to the reactive species in plasma. After DBD plasma exposure at 43.0 W for 8 min, there was approximately an 8.4-fold increase in surface hydrophobicity of HRP. After exposure to DBD plasma, the aggregation of HRP was observed by using atomic force microscopy analysis. In conclusion, DBD plasma causes structural changes and chemical modification of HRP, which may be responsible for the loss of enzymatic activity. These data contribute to the application of cold plasma in the control of enzymatic browning of food products during processing and storage.

Enzyme-assisted bioremediation approach for synthetic dyes and polycyclic aromatic hydrocarbons degradation.

Environmental protection from emerging pollutants has become a significant challenge for mankind as an increasing number of contaminants, including synthetic dyes and polycyclic aromatic hydrocarbons (PAHs), represent a serious risk to ecological and environmental balance. Most synthetic dyes have complex aromatic structures and are resistant to degrade by classical approaches, such as physical and chemical processes, including adsorption, chemical coagulation, flocculation, ion exchange, membrane separation, froth flotation, and reverse osmosis. Enzymes-assisted catalytic transformation of pollutants has become a potential alternative to classical methods because of their ability to react with complex compounds, a quick degradation rate, and producing less harmful by-products. Plant peroxidases, and microbial laccase and lignin-degrading peroxidases (manganese and lignin peroxidase) have gained significant attention for treating aromatic waste due to their capability of oxidizing and detoxifying a wide range of recalcitrant xenobiotics, including PAHs and synthetic dyes. Peroxidases being efficient biocatalysts detoxify an array of toxic compounds by simple free-radical mechanism resulting in the formation of oxidized and depolymerized products of significantly reduced toxicity. Moreover, it is an ecofriendly and economically favorable approach towards the biodegradation of recalcitrant and toxic industrial waste. Among microbial and plant peroxidases, bacterial enzymes have broad substrate specificity and can transform a wide range of recalcitrant substrates. Ligninolytic enzymes oxidize the aromatic ring into quinones and acids by producing free hydroxyl radicals instead of dihydrodiols and mineralize aromatic hydrocarbon in combination with cytochrome P450, monooxygenases, and epoxide hydrolases. In the review, an attempt has been made to provide detailed knowledge about the availability of inexpensive peroxidases sources, their mechanism of action, and degradation potential. The present review summarizes the exploitation of peroxidases from plants, bacteria, and fungus (manganese peroxidase, lignin peroxidase, and laccases) for detoxification and degradation of textile dyes as well as PAHs. Conclusively, peroxidases have great potential to react with almost all classes of synthetic dyes and most PAHs due to broad substrate specificity and transformed them into less harmful metabolites.

Role of PGPR on the physiology of sunflower irrigated with produced water containing high total dissolved solids (TDS) and its residual effects on soil fertility

The present study was conducted to evaluate the bioremediation potential of plant growth-promoting rhizobacteria (PGPR) PGPR isolates from high total dissolved solids (TDS) bearing produced water on the water quality, soil physicochemical properties and growth and physiology of sunflower irrigated with high TDS bearing produced water having salinity level 130 times higher above seawater and also containing traces of oil and grease. Seeds of sunflower hybrid Parsun 3 were soaked for 3–4 h prior to sowing in 72 h old culture of PGPR strains W1 and W2 isolated from high TDS bearing polluted water. The control plants were irrigated with 90% diluted TDS water supplemented with 5 ml LB media. Whereas, the inoculated plants were irrigated with 90% diluted TDS water supplemented with 5 ml PGPR inocula.in LB media. The plants were grown under natural conditions. The 16S rRNA sequence analyses identified the isolate W1 bearing 100% similarity with the plant growth-promoting rhizobacteria (PGPR) Ralstonia pickettii and W2 bearing 99.7% similarity with Brevibacillus invocatus. Both the isolate were catalase and oxidase positive. The Ralstonia pickettii and Brevibacillus invocatus treatments decreased the EC and TDS values significantly such that the EC and TDS values of 90% diluted TDS water were 29 times and 19 times higher than tap water. Sodium adsorption ratio (SAR), organic matter, nitrogen, potassium, magnesium and carbon content were 1.96, 1.10, 2.28 1.20, 6.63 and 1.00 times greater than control in the rhizosphere soil of Ralstonia pickettii inoculated plants irrigated with high TDS bearing water There were significant increases in plant growth, sugar, flavonoids and phenolics, chlorophyll b, total chlorophyll, carotenoids content and activities of superoxide dismutase, catalase and peroxidase in plants inoculated with Ralstonia pickettii and Brevibacillus invocatus. The flavonoids, phenolics and proline contents were 0.54, 0.72 and 0.30 times higher in Ralstonia pickettii inoculated plants. Shoot/root dry weight ratio was about (50%) lower than control in Ralstonia pickettii and Brevibacillus invocatus treatments. Ralstonia pickettii was more effective than Brevibacillus invocatus to combat oxidative and osmotic stresses. It is inferred that the high TDS bearing produced water from oil factory harbor Plant growth-promoting rhizobacteria (PGPR) having the potential to combat high salinity stress in plants when used as bioinoculant. The broth culture containing the bacteria may be supplemented with the saline water used for irrigation as it provides nutrients for the growth and proliferation of bacteria present in the saline water and hence the synergistic action of bacterial inocula with the indigenous bacteria present in saline water may better alleviate osmotic and oxidative stresses of plants encountered under salinity stress. The residual effect of Ralstonia pickettii on organic matter and Ca, Mg, K and P content of the rhizosphere soil was notably higher for succeeding crops. Novelty statement This is the first report demonstrating that rhizobacteria can proliferate in water containing salinity higher above seawater in addition to oil grease and TSS. Their efficiency to reduce TDS can be augmented by an exogenous supply of LB broth culture of PGPR isolated from the polluted water. These indigenous rhizobacteria when used as bioinoculant on the plant can act as plant growth promoters as well as bioremediation of salinity effects.

Copper nanoclusters promote tomato (Solanum lycopersicum L.) yield and quality through improving photosynthesis and roots growth

The innovative and sustainable technologies are highly needed to decrease serious environmental problems from current agriculture. Herein, the green and biosafe copper-based nano-agriculture was described for tomato production. Prepared Cu nanoclusters (NCs) showed small size (3.0 ± 0.5 nm) and high bioavailability. At low concentration (1 mg kg−1) in soil, Cu NCs improved the activities of antioxidant enzymes (superoxide dismutase, catalase and peroxidase) in the tomato plants, which could help to slow down leaf aging, increase photosynthesis and carbohydrates content by 19.4 % and 14.9 %, respectively. Cu NCs promoted the roots' growth, especially increasing the root tip’ number, which might contribute to the increase in absorption of macronutrients (K, Mg and P) and micronutrients (B, Mn, Cu and Zn). The Cu NCs (1 mg kg−1) promoted tomato growth and increased the tomato fruit yields by 12.2 % compared to the control. Moreover, the tomato fruit qualities had been improved meanwhile the accumulation of Cu in fruits was not observed. These findings indicate that the Cu NCs have potential to be safely applied for tomato production.

A new peroxidase from the roots of the Algerian white turnip (Brassica rapa, variety rapa): extraction, purification, characterisation, and antioxidant potential

Due to its various biological activities, the roots of Brassica rapa (turnip), has been applied as a therapeutic agent in traditional medicine. The current study aimed to purify a plant peroxidase (POD; designated as TRP) from Algerian white turnip (B. rapa, variety rapa) roots, to homogeneity and to characterise it biochemically. The molecular weight of the purified TRP was determined to be ∼58 kDa as estimated by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) and high-performance liquid chromatography (HPLC). The TRP Reinheitzahl values (RZ) and specific activity were 2.9 and 14,500 U/mg, respectively. Its N-terminal sequence exhibited high identity with those of class III-PODs. TRP showed optimal activity at 55 °C and pH 6 (guaiacol), was completely inhibited by sodium azide (NaN3) and potassium cyanide (KCN) and exhibited greater catalytic efficiency than that of the well-known horseradish peroxidase (HRP) from Armoracia rusticana. TRP demonstrated antioxidant activities with 45% and 61.49% of 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS•) and hydroxyl (•OH) radical scavenging, respectively, as well as ferrous ion chelating (52.96%) and reducing (48.32%) powers. This study provides information regarding the potential role of TRP in enzyme therapy (as applied in the pharmaceutical and medicinal industries), with biological eradication of free radicals.