Search Results (66)

Arsenic (As) contamination poses a critical threat to agricultural productivity, affecting rapeseed (Brassica napus L.), an agronomically important crop. A comparative assessment was performed to evaluate the efficacy of chemogenic and biogenic manganese nanoparticles (C-MnNPs and B-MnNPs) for mitigating As toxicity. B-MnNPs were biosynthesized using cell-free filtrate of Bacillus pumilus MAY4, while C-MnNPs were obtained from Cwnano Co., Ltd. (Shanghai, China). Greenhouse assays demonstrated that both C-MnNPs and B-MnNPs alleviated detrimental effects of As; however, B-MnNPs exhibited superior performance compared to their chemical counterparts. Compared to As-stressed plants, B-MnNPs enhanced leaf and root biomass (26.4% and 56.15%, respectively), net photosynthetic rate (64.8%), and stomatal conductance (50%). B-MnNPs more effectively reduced oxidative stress markers by activating antioxidant defense systems in both leaf and root tissues. Furthermore, B-MnNPs reduced in planta As accumulation while significantly improving uptake of essential nutrients, including potassium, phosphorous, magnesium, and manganese, etc., in rapeseed plants. Expression studies revealed that B-MnNPs upregulated antioxidant defense and redox homeostasis related stress-responsive genes under induced As stress. Biochemical assays further confirmed the enrichment of stress-responsive phytohormones, including salicylic acid, jasmonic acid, and abscisic acid, in B-MnNP-treated As-stressed rapeseed plants, indicating activation of multi-tier defense response by B-MnNPs to cope with As stress. These findings establish B-MnNPs as a highly effective nano-enabled strategy for managing As toxicity in the rapeseed cultivation system. This research provides critical insights into the molecular and physiological mechanisms underlying MnNP-mediated stress tolerance and offers a promising green nanotechnology approach for heavy metal-resilient crops. Full article

The irrigation of crops with As-enriched water, along with the use of agrochemicals and mining, are considered the main source of accumulation of this element in arable land and thus, in plants. The aim of this study is to analyze the responses of As at five different concentrations, in the germination of seeds of tomato (Solanum lycoperisum), through measuring the morphological variables (root, shoot and total length), phenolic compounds, antioxidant activity, arsenic content and phytochemical profile of the sprouts. After 12 days, 89.16% germinated. According to the germination variables of Germination percentage, Germination rate, Mean germination time, Seed vigor index and percent of phytotoxicity, treatment 0.8 ppm shows a better performance in comparison with the rest. The stem, root and total length showed differences with control at 0.8 and 5 ppm. Phenolic compounds and antioxidant activity in the sprouts among treatments showed a potential range of hormesis between 0.8 and 2 ppm. Treatment 5 ppm showed the worse performance. The sprouts showed that the accumulation of As increased with the concentration of the treatment. The behavior of the variables measured suggest the activation of a stress response in the sprout causing positive effects such as growth enhancing, faster and better germination process and more production of molecules of biochemical interest. The opposite of the latter were also found. These findings provide an insight into the development of seeds under As contamination in irrigation water. Full article

Arsenic pollution is a global environmental challenge, necessitating efficient and sustainable remediation technologies. This study investigates the synergistic effect of the arsenic-resistant bacterium Burkholderia contaminans ZCC (ZCC) and corn stalk biochar (BC) on arsenic-contaminated soil, with Pteris vittata as the remediation plant. Through pot experiments, we evaluated the effects of various BC addition rates (0%, 1%, 5%) and ZCC inoculation on soil pH, plant growth, physiological responses, and arsenic accumulation. Biochar alone significantly increased soil pH (reaching 7.56 in the 5% BC treatment), while B. contaminans ZCC alone had a weaker effect. In combined treatments, pH changes were primarily driven by biochar. The combination of B. contaminans ZCC and BC enhanced P. vittata growth, with the 5% BC + ZCC treatment showing the greatest increase in total plant biomass (2.56 times that of the control) and total chlorophyll content (43.32% higher). This treatment also activated antioxidant systems (increased SOD, POD, and CAT activities), reduced oxidative damage (lower MDA content), and improved osmotic regulation (higher proline content). Notably, B. contaminans ZCC and BC synergistically enhanced arsenic accumulation in the P. vittata plant, with the arsenic content under the 5% BC + ZCC treatment being 2.81 times that of the control. This study demonstrates that the combination of B. contaminans ZCC and BC enhances arsenic remediation through soil improvement and plant growth promotion. Full article

Agricultural activities are widely recognized as major sources of water pollution, primarily due to the introduction of heavy metals (HMs) through fertilizers, pesticides, manures, sewage sludge, and irrigation water. Owing to their persistence and non-biodegradability, these metals pose substantial risks to ecosystems and public health. While certain HMs such as cobalt, copper, and zinc are essential micronutrients for crops at low concentrations, others—like arsenic, cadmium, lead, and mercury—enter agricultural systems as contaminants and serve no biological function in plants. This paper explores the complex issue of HM contamination in water resulting from agricultural practices. It reviews the primary sources and pathways through which HMs enter aquatic systems, discusses their ecological and health impacts, and examines analytical methods used for HM detection and monitoring. In response to this challenge, several mitigation strategies are highlighted, including the optimized use of agrochemicals, adoption of sustainable farming practices, and implementation of phytoremediation and bioremediation techniques. Additionally, the importance of community education and regulatory enforcement is emphasized as part of an integrated approach to pollution control. Ultimately, this paper underscores the need for balanced solutions that safeguard water resources while maintaining agricultural productivity. Full article

Heavy metal pollution represents a pervasive environmental challenge that significantly exacerbates the ever-increasing crisis of antimicrobial resistance and the capacity of microorganisms to endure and proliferate despite antibiotic interventions. This review examines the intricate relationship between heavy metals and AMR, with an emphasis on the underlying molecular mechanisms and ecological ramifications. Common environmental metals, including arsenic, mercury, cadmium, and lead, exert substantial selective pressures on microbial communities. These induce oxidative stress and DNA damage, potentially leading to mutations that enhance antibiotic resistance. Key microbial responses include the overexpression of efflux pumps that expel both metals and antibiotics, production of detoxifying enzymes, and formation of protective biofilms, all of which contribute to the emergence of multidrug-resistant strains. In the soil environment, particularly the rhizosphere, heavy metals disrupt plant–microbe interactions by inhibiting beneficial organisms, such as rhizobacteria, mycorrhizal fungi, and actinomycetes, thereby impairing nutrient cycling and plant health. Nonetheless, certain microbial consortia can tolerate and detoxify heavy metals through sequestration and biotransformation, rendering them valuable for bioremediation. Advances in biotechnology, including gene editing and the development of engineered metal-resistant microbes, offer promising solutions for mitigating the spread of metal-driven AMR and restoring ecological balance. By understanding the interplay between metal pollution and microbial resistance, we can more effectively devise strategies for environmental protection and public health. Full article

MicroRNA528 (miR528) is a microRNA found only in monocotyledonous (monocot) plants. It has been widely reported that miR528 is involved in the regulation of plant growth and development, such as flowering, architecture, and seed and embryogenic development, in addition to playing a crucial role in response to various biotic and abiotic stresses, such as plant pathogens, salt stress, heat/cold stress, water stress, arsenic stress, oxidative stress, heavy-metal stress, and nutrient stress. Given that it is specific to monocot plants, to which the major staple food crops such as rice and wheat belong, a review of studies investigating its diverse functional roles and underlying mechanisms is presented. This review focuses on the processes in which miR528 and its targets are involved and examines their regulatory relationships with significant participation in plant development and stress responses. It is anticipated that more biological functions and evolutionary effects of miRNA targets will be elucidated with the increase in knowledge of miRNA evolution and examination of target mRNAs. Full article

Calcium-dependent protein kinases (CDPKs) are crucial regulators in calcium-mediated signal transduction pathways, playing a pivotal role in plant response to abiotic stresses. However, there is still limited knowledge regarding the genes of the Populus tomentosa CDPK family and their underlying functions in response to arsenic (As) stress and arbuscular mycorrhizal fungi (AMF) colonization. In our study, 20 PtCDPKs were identified in the P. tomentosa genome. Phylogenetic analysis categorized these PtCDPK genes into four subgroups based on sequence homology. Motif analysis revealed that PtCDPK genes within the same group share a similar exon–intron structure, conserved domains, and composition. The promoters of PtCDPK genes were found to contain a multitude of cis-acting elements, including light-response elements, phytohormone-response elements, and stress-response elements. The analysis of genes provided insights into the evolutionary dynamics and expansion of the PtCDPK gene family within P. tomentosa. The PtCDPK genes exhibited a strong collinear relationship with the CDPK genes of two model plants, namely, Arabidopsis thaliana and Oryza sativa L. Specifically, 10 gene pairs showed collinearity with Arabidopsis; in contrast, 14 gene pairs were collinear with rice. Transcriptome analysis of gene expression levels in P. tomentosa roots under both As stress and arbuscular mycorrhizal fungi (AMF) colonization conditions revealed that 20 PtCDPK genes had differential expression patterns. Under As stress, AMF inoculation led to the upregulation of 11 PtCDPK genes (PtCDPKSK5, X2, 1-3, 20-1, 24, 26-X1-1, 26-X1-2, 29-1, 29-2, 32, and 32-X1) and the downregulation of 8 PtCDPK genes, including PtCDPK1-1, 1-2, 8-X1, 10-X4, 13, 20-2, 26-X2, and 26-X3. The RT-qPCR results for 10 PtCDPK genes were consistent with the transcriptome data, indicating that AMF symbiosis plays a regulatory role in modulating the expression of PtCDPK genes in response to As stress. The principal findings of this study were that PtCDPK genes showed differential expression patterns under As stress and AMF colonization, with AMF regulating PtCDPK gene expression in response to As stress. Our study contributes to developing a deeper understanding of the function of PtCDPKs in the Ca²⁺ signaling pathway of P. tomentosa under As stress and AMF inoculation, which is pivotal for elucidating the molecular mechanisms underlying As tolerance in AMF-inoculated P. tomentosa. Full article

This review provides an in-depth examination of the intricate interactions between plant metabolites and the digestive and antioxidative enzymes in insects, highlighting their essential roles in shaping insect herbivory and adaptation strategies. Plants have evolved a diverse arsenal of secondary metabolites to defend against herbivorous insects, which, in response, have developed sophisticated adaptations to overcome these defenses and efficiently exploit plant resources. We outline the importance of digestive enzymes, such as proteases and amylases, which allow insects to break down complex plant compounds and access vital nutrients. Additionally, the review focuses on antioxidative enzymes in the insect midgut, including superoxide dismutase and catalase, which play a crucial role in mitigating oxidative stress generated during digestion and other metabolic processes. Synthesizing findings from various studies, this review also considers how environmental factors, such as heavy metal exposure and temperature changes, influence these enzymes’ activity levels. It highlights the dual function of antioxidative enzymes in detoxifying harmful plant-derived compounds while preserving cellular stability. The implications of these biochemical interactions for pest management are discussed, with an emphasis on the potential for developing biopesticides that target specific enzymatic pathways to disrupt insect feeding and growth. By elucidating the biochemical mechanisms that underlie plant-insect interactions, this review enhances our understanding of co-evolutionary dynamics and offers insights into sustainable agricultural practices that could leverage these interactions for effective pest control. Finally, the review proposes future research directions aimed at identifying novel plant metabolites with enzyme-modulating properties and exploring the ecological impacts of enzyme-targeted pest management approaches. Full article

Rhizobial bacteria perform a number of extremely important functions in the soil environment. In addition to fixing molecular nitrogen and transforming it into a form available to plants, they participate in the circulation of elements and the decomposition of complex compounds present in the soil, sometimes toxic to other organisms. This review article describes the molecular mechanisms occurring in the most diverse group of rhizobia, the genus Bradyrhizobium, allowing these bacteria to adapt to selected substances found in the soil. Firstly, the adaptation of bradyrhizobia to low and high concentrations of elements such as iron, phosphorus, sulfur, calcium and manganese was shown. Secondly, the processes activated in their cells in the presence of heavy metals such as lead, mercury and arsenic, as well as radionuclides, were described. Additionally, due to the potential use of Bradyrhziobium as biofertilizers, their response to pesticides commonly used in agriculture, such as glyphosate, sulfentrazone, chlorophenoxy herbicides, flumioxazine, imidazolinone, atrazine, and insecticides and fungicides, was also discussed. The paper shows the great genetic diversity of bradyrhizobia in terms of adapting to variable environmental conditions present in the soil. Full article

Plants are exposed to a diverse range of biotic stressors, including fungi, bacteria, nematodes, insects and viruses. To combat these enemies, plants have developed an arsenal of defense mechanisms over time, among which secondary metabolites are the most effective. Moreover, to overcome the negative impact of chemical pesticides, the plant’s secondary metabolites can be harnessed to develop novel disease management strategies. Alkaloids, flavonoids, terpenes and essential oils are major pathogen/pest-responsive secondary metabolite classes in plants. Among these, saponins have shown significant potential in suppressing a wide range of plant pathogens. However, they are yet to be explored thoroughly compared to other secondary metabolites in plant defense, and therefore, a low number of disease control agents exist in agri-markets based on saponins. Thus, this review aims to rectify this bias by identifying and acknowledging the significance of saponins as being on par with other classes of secondary metabolites in plant defense systems. It also provides the first holistic review on the role of saponins with known mechanisms against all of the major plant pathogens/pests. Furthermore, this review discusses the potential of saponin-rich crops in providing eco-friendly pest/pathogen management products for integrated pest management (IPM) and prospectives on the potential of saponin derivatives in developing novel biocides for sustainable agriculture. Full article

Arsenate (AsV) is absorbed and accumulated by plants, which can affect their physiological activities, disrupt gene expression, alter metabolite content, and influence growth. Despite the potential of zinc oxide nanoparticles (ZnONPs) to mitigate the adverse effects of arsenic stress in plants, the underlying mechanisms of ZnONPs-mediated detoxification of AsV, as well as the specific metabolites and metabolic pathways involved, remain largely unexplored. In this study, we demonstrated root metabolomic profiling of soybean germinating seedlings subjected to 25 μmol L⁻¹ arsenate (Na₂HAsO₄) and ZnONPs at concentrations of 25 μmol L⁻¹ (ZnO25) and 50 μmol L⁻¹ (ZnO50). The objective of this study was to examine the effects on soybean root metabolomics under AsV toxicity. Metabolomic analysis indicated that 453, 501, and 460 metabolites were significantly regulated in response to AsV, ZnO25, and ZnO50 treatments, respectively, compared to the control. Pathway analysis of the differentially regulated metabolites (DRMs) revealed that the tricarboxylic acid (TCA) cycle, glutathione metabolism, proline and aldarate metabolism, and arginine and proline metabolism were the most statistically enriched pathways in ZnONPs-supplemented plants. These findings suggest that ZnONPs enhance the tolerance response to AsV. Collectively, our results support the hypothesis that ZnONPs fertilization could be a potential strategy for improving soybean crop resilience under AsV stress. Full article

Heavy metals in soil can inflict direct damage on plants growing within it, adversely affecting their growth height, root development, leaf area, and other physiological traits. To counteract the toxic impacts of heavy metals on plant growth and development, plants mitigate heavy metal stress through mechanisms such as metal chelation, vacuolar compartmentalization, regulation of transporters, and enhancement of antioxidant functions. WRKY transcription factors (TFs) play a crucial role in plant growth and development as well as in responses to both biotic and abiotic stresses; notably, heavy metal stress is classified as an abiotic stressor. An increasing number of studies have highlighted the significant role of WRKY proteins in regulating heavy metal stress across various levels. Upon the entry of heavy metal ions into plant root cells, the production of reactive oxygen species (ROS) is triggered, leading to the phosphorylation and activation of WRKY TFs through MAPK cascade signaling. Activated WRKY TFs then modulate various physiological processes by upregulating or downregulating the expression of downstream genes to confer heavy metal tolerance to plants. This review provides an overview of the research advancements regarding WRKY TFs in regulating heavy metal ion stress—including cadmium (Cd), arsenic (As), copper (Cu)—and aluminum (Al) toxicity. Full article

The Toce River (Northern Italy) is characterized by legacy contamination of dichloro-diphenyl-trichloroethane (DDT), mercury, and arsenic deriving from an industrial plant active between ca. 1915 and 1996. Chironomidae taxa assemblages and sediments were collected in 2014 and 2019 upstream and downstream of the industrial area to analyze species responses to toxic substances in a river stretch with relatively uniform natural (i.e., hydro-morphological) characteristics. A total of 32 chironomid taxa were identified. Sediment concentrations reached levels potentially toxic for benthic invertebrates: 15.7 µg kg⁻¹ 1% organic carbon for DDT, 197 µg kg⁻¹ dry weight (d.w.) for Hg, and 55.7 mg kg⁻¹ d.w. for As. Canonical Correspondence Analysis (CCA) revealed a predominant seasonal gradient, followed by an upstream-downstream gradient. Partial CCA indicated that 5.2% of the total variation was associated with sediment contamination. Self-Organizing Maps (SOMs) were used to represent species responses to toxicants. Most species appeared to be tolerant, e.g., Chironomus riparius, Micropsectra atrofasciata, Conchapelopia pallidula, and Polypedilum spp. Sensitivity to contaminants was observed in only a few species: Diamesa spp., Sympotthastia spinifera, and Prodiamesa olivacea to DDT; Potthastia longimanus to Hg; Odontomesa fulva and Microtendipes pedellus to As. The chironomid community was characterized in presence of contamination levels commonly observed in freshwater ecosystems. Full article

Mercury (Hg) pollution not only poses a threat to the environment but also adversely affects the growth and development of plants, with potential repercussions for animals and humans through bioaccumulation in the food chain. Maize, a crucial source of food, industrial materials, and livestock feed, requires special attention in understanding the genetic factors influencing mercury accumulation. Developing maize varieties with low mercury accumulation is vital for both maize production and human health. In this study, a comprehensive genome-wide association study (GWAS) was conducted using an enlarged SNP panel comprising 1.25 million single nucleotide polymorphisms (SNPs) in 230 maize inbred lines across three environments. The analysis identified 111 significant SNPs within 78 quantitative trait loci (QTL), involving 169 candidate genes under the Q model. Compared to the previous study, the increased marker density and optimized statistical model led to the discovery of 74 additional QTL, demonstrating improved statistical power. Gene ontology (GO) enrichment analysis revealed that most genes participate in arsenate reduction and stress responses. Notably, GRMZM2G440968, which has been reported in previous studies, is associated with the significant SNP chr6.S_155668107 in axis tissue. It encodes a cysteine proteinase inhibitor, implying its potential role in mitigating mercury toxicity by inhibiting cysteine. Haplotype analyses provided further insights, indicating that lines carrying hap3 exhibited the lowest mercury content compared to other haplotypes. In summary, our study significantly enhances the statistical power of GWAS, identifying additional genes related to mercury accumulation and metabolism. These findings offer valuable insights into unraveling the genetic basis of mercury content in maize and contribute to the development of maize varieties with low mercury accumulation. Full article

Biochar could be a brilliant additive supporting the anaerobic fermentation process. However, it should be taken into account that in some cases it could also be harmful to microorganisms responsible for biogas production. The negative impact of carbon materials could be a result of an overdose of biochar, high biochar pH, increased arsenic mobility in the methane fermentation solution caused by the carbon material, and low porosity of some carbon materials for microorganisms. Moreover, when biochar is affected by an anaerobic digest solution, it could reduce the biodiversity of microorganisms. The purpose of the article is not to reject the idea of biochar additives to increase the efficiency of biogas production, but to draw attention to the properties and ways of adding these materials that could reduce biogas production. These findings have practical relevance for organizations seeking to implement such systems in industrial or local-scale biogas plants and provide valuable insights for future research. Needless to say, this study will also support the implementation of biogas technologies and waste management in implementing the idea of a circular economy, further emphasizing the significance of the research. Full article