The Roles of Environmental Factors in Regulation of Oxidative Stress in Plant

Biochemical responses of Echinochloa polystachya inoculated with a Trichoderma consortium during the removal of a pyrethroid-based pesticide

The biochemical response of plants exposed to pesticides and inoculated with microorganisms is of great importance to explore cleaning up strategies for contaminated sites with pyrethroid-based pesticides. We evaluated the effects of a Trichoderma consortium on the biochemical responses of Echinochloa polystachya plants during the removal of a pyrethroid-based pesticide. Plants were inoculated or not with the Trichoderma consortium and exposed to commercial pesticide H24®, based on pyrethroids. Pesticide application resulted in significant reduction in root protein content (58%), but enhanced content of malondialdehyde (MDA) in shoots, superoxide dismutase (SOD) activity in shoots and roots, and catalase (CAT) activity in roots. Inoculation of Trichoderma consortium in E. polystachya exposed to the pesticide resulted in increased protein content in roots and MDA content in shoots (2-fold). Trichoderma consortium improved protein content and SOD activity (140-fold) in plants. Fungal inoculation increased the removal (97.9%) of the pesticide in comparison to the sole effect of plants (33.9%). Results allow further understanding about the responses of the interaction between plants and root-associated fungi to improving the assisted-phytoremediation of solid matrices contaminated with organic pesticides.

Exopolysaccharides of lactic acid bacteria as protective agents against bacterial and viral plant pathogens

In this study, 25 exopolysaccharides produced by lactic acid bacteria (LAB) were screened for their effect on plant pathogens. The molecular masses of EPS were found to be 3,8-5,0 × 104 Da. The GC-MS analysis revealed that EPSs were majorly composed of glucose (85.85-97.98 %). The FT-IR spectra of EPSs were in agreement with the typical absorption peaks of polysaccharides. EPSs showed a hydroxyl radical scavenging ability. The scavenging rate of EPS ranged from 20 to 50 % at a concentration of 5.0 mg/mL. Significant growth delay of phytopathogenic bacteria was observed after 3-6 h of cultivation. Optical density values of indicator cultures growing in the medium with EPS (1 mg/mL) were lower compared to the control by 24-100 % for Pseudomonas fluorescens, 9-46 % for P. syringae, 47-79 % for Pectobacterium carotovorum, 14-90 % for Clavibacter michiganensis, 9-100 % for Xantomonas campestris, and 45-100 % for X. vesicatorium. EPS retained their inhibitory effect on the growth of X. campestris, X. vesicatorium and C. michiganensis strains after 24-48 h of cultivation, but stimulating effect on the growth of some strains also was observed. LAB EPS showed antibiofilm activity against P. carotovorum, P. syringae, and P. fluorescent, decreasing their biofilm formation by 16-50 %, 14-39 %, and 29-59 %, respectively. Also, stimulation of biofilm formation by X. campestris (by 8-29 %), X. vesicatorium (by 3-32 %) and C. michiganensis (by 31-41 %) strains was observed. EPSs showed antiviral activity against tobacco mosaic virus (TMV). At a concentration of 100 μg/mL, they decreased the infective ability of TMV by 61-92 %. This is the first study demonstrating that LAB EPS exhibited in vitro antibacterial and antibiofilm activity against phytopathogenic bacteria and anti-viral activity against TMV. Thus, LAB EPSs could have great potential for plant protection strategies.

Hydrolysates from cauliflower and artichoke industrial wastes as biostimulants on seed germination and seedling growth: a chemical and biological characterization

BACKGROUND

Cauliflower (Brassica oleracea L.) and globe artichoke (Cynara scolymus L.) are vegetables with a high waste index mainly related to stems and leaves. In this study, enzymatic hydrolysates obtained from these wastes were proposed to be used as plant biostimulants. Life cycle assessment methodology was also applied to evaluate environmental performances related to cauliflower and artichoke byproducts.

RESULTS

Hydrolysates (HYs) were chemically and biologically characterized. Amino acids, organic acids, amines, polyols, mineral elements, phenols, tannins, flavonoids and sulfur compounds were identified and quantified by means of NMR, inductively coupled plasma mass spectrometry and UV-visible analyses. Cauliflower leaf and flower HYs showed the highest concentration of free amino acids, whereas stems showed the highest concentration of Ca. Regarding artichoke, asparagine, glutamine and aspartic acid were exclusively detected in stems, whereas artichoke leaves showed the highest Mg and Mn levels together with the highest antioxidant activity. The HYs diluted in water were tested as biostimulants. The impacts of five concentrations of HYs (0.00, 0.28, 0.84, 2.52 and 7.56 g L-1) on seed germination and early seedling growth of crimson clover, alfalfa, durum wheat and corn were investigated.

CONCLUSIONS

The application of artichoke biostimulant (0.28 g L-1) positively influenced the coefficient of velocity of germination in alfalfa, crimson clover and durum wheat, whereas cauliflower biostimulant significantly improved corn germination speed. © 2024 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Interference with Histone Deacetylase 4 Regulates c-Jun N-terminal Kinase/Activating Protein-1 Signaling to Ameliorate Sepsis-induced Alveolar Epithelial Cell Injury

ABSTRACT

Sepsis is a syndrome of systemic inflammatory response resulting from infection, which can lead to severe lung injury. Histone deacetylase 4 (HDAC4) is a key protein known to regulate a wide range of cellular processes. This study was designed to investigate the role of HDAC4 in lipopolysaccharide (LPS)-induced alveolar epithelial cell injury as well as to disclose its potential molecular mechanisms. The alveolar epithelial cell injury model was established by inducing A549 cells with LPS. A549 cell viability was detected by cell counting kit-8 assay and the transfection efficiency of small interfering RNA targeting HDAC4 was appraised utilizing Western blot. The levels of inflammatory cytokines and oxidative stress markers were detected using corresponding assay kits. Dichloro-dihydro-fluorescein diacetate assay was used for the measurement of reactive oxygen species (ROS) content. Flow cytometry, 5,5',6,6'-tetrachloro-1,1',3,3'- tetraethyl-benzimidazolyl-carbocyanine iodide-1 staining, adenosine triphosphate (ATP) assay kits, and MitoSOX Red assay kits were employed to estimate cell apoptosis, mitochondrial membrane potential, ATP level, and mitochondrial ROS level, respectively. The oxygen consumption rate of A549 cells was evaluated with XF96 extracellular flux analyzer. Western blot was applied for the evaluation of HDAC4, apoptosis- and c-Jun N-terminal kinase (JNK)/activating protein-1 (AP-1) signaling pathway-related proteins. HDAC4 expression was found to be increased in LPS-induced A549 cells and HDAC4 silence inhibited inflammatory damage, repressed oxidative stress, alleviated cell apoptosis, improved mitochondrial function, and blocked JNK/AP-1 signaling in A549 cells stimulated by LPS, which were all reversed by JNK activator anisomycin. Collectively, the interference with HDAC4 could ameliorate LPS-induced alveolar epithelial cell injury, and such protective effect may be potentially mediated through the JNK/AP-1 signaling pathway.

Optimization of Phenolic Compounds Extraction from Aerial Parts of Fabiana punensis S. C. Arroyo by Ultrasound- and Microwave-Assisted Extraction

Fabiana punensis S. C. Arroyo is a subshrub or shrub that is indigenous to the arid and semiarid region of northern Argentina and is known to possess several medicinal properties. The objective of this study was to optimize the extraction conditions so as to maximize the yield of bioactive total phenolic compound (TPC) and flavonoids (F) of F. punensis' aerial parts by using non-conventional extraction methods, namely ultrasound-assisted extraction, UAE, and microwave-assisted extraction, MAE, and to compare the biological activities and toxicity of optimized extracts vs. conventional extracts, i.e., those gained by maceration. Response Surface Methodology (RSM) was used to apply factorial designs to optimize the parameters of extraction: solid-to-liquid ratio, extraction time, ultrasound amplitude, and microwave power. The experimental values for TPC and F and antioxidant activity under the optimal extraction conditions were not significantly different from the predicted values, demonstrating the accuracy of the mathematical models. Similar HPLC-DAD patterns were found between conventional and UAE- and MAE-optimized extracts. The main constituents of the extracts correspond to phenolic compounds (flavonoids and phenolic acids) and apigenin was identified. All extracts showed high scavenger capacity on ABTS•+, O2•- and H2O2, enabling the inhibition of the pro-inflammatory enzymes xanthine oxidase (XO) and lipoxygenase (LOX). They also showed an antimutagenic effect in Salmonella Typhimurium assay and cytotoxic/anti-proliferative activity on human melanoma cells (SKMEL-28). Toxicological evaluation indicates its safety. The results of this work are important in the development of efficient and sustainable methods for obtaining bioactive compounds from F. punensis for the prevention of chronic degenerative diseases associated with oxidative stress, inflammation, and DNA damage.

Physiological, biochemical and transcriptomic insights into the mechanisms by which molybdenum mitigates cadmium toxicity in Triticum aestivum L

There are many heavy metal stresses in agricultural biological systems, especially cadmium (Cd) stress, which prevent the full growth of plants, lead to a serious decline in crop yield, and endanger human health. Molybdenum (Mo), an essential nutrient element for plants, regulates plant growth mainly by reducing the absorption of heavy metals and protecting plants from oxidative damage. The aim of this study was to determine the protective effect of Mo (1 μM) application on wheat plants under conditions of Cd (10 μM) toxicity. The biomass, Cd and Mo contents, photosynthesis, leaf and root ultrastructure, antioxidant system, and active oxygen content of the wheat plants were determined. Mo increased the total chlorophyll content of wheat leaves by 43.02% and the net photosynthetic rate by 38.67%, and ameliorated the inhibitory effect of cadmium on photosynthesis by up-regulating photosynthesis-related genes and light-trapping genes. In addition, Mo reduced the content of superoxide anion (O2•-) by 16.55% and 31.12%, malondialdehyde (MDA) by 20.75% and 7.17%, hydrogen peroxide (H2O2) by 24.69% and 8.17%, and electrolyte leakage (EL) by 27.59% and 16.82% in wheat leaves and roots, respectively, and enhanced the antioxidant system to reduce the burst of reactive oxygen species and alleviate the damage of Cd stress on wheat. According to the above results, Mo is considered a plant essential nutrient that enhances Cd tolerance in wheat by limiting the absorption, accumulation and transport of Cd and by regulating antioxidant defence mechanisms. ENVIRONMENTAL IMPLICATION: Cadmium (Cd)，is one of the most toxic heavy metals in the environment, and Cd pollution is a global environmental problem that threatens food security and human health. Molybdenum (Mo), as an essential plant nutrient, is often used to resist environmental stress. However, the mechanism of Mo treatment on wheat subjected to Cd stress has not been reported. In this study, we systematically analysed the effects of Mo on the phenotype, physiology, biochemistry, ultrastructure and Cd content of wheat subjected to Cd stress, and comprehensively analysed the transcriptomics. It not only reveals the mechanism of Mo tolerance to Cd stress in wheat, but also provides new insights into phytoremediation and plant growth in Cd-contaminated soil.

Life Cycle Assessment of an Avocado: Grown in South Africa-Enjoyed in Europe

Food production is known to have significant environmental impacts, with the main contributors residing in the farming and transportation life cycle phases. Of the various food products transported around the world, avocados have increasingly gained attention as a high-commodity superfood. Avocados require specific climatic and agricultural conditions for farming, with the most fertile land and conditions located outside Europe. Consequently, most avocados consumed in Europe are imported over vast geographical distances, with little information available to quantify the environmental impacts of this imported superfood. This paper aims to present the most detailed life cycle assessment results of an avocado cultivated, grown and harvested in the Limpopo Province of South Africa and exported to the European market for sale and consumption. A life cycle assessment was developed for the farming, harvesting, handling, packaging, ripening, transportation, and carbon sequestration potential of the avocado, and it was used to conduct a holistic life cycle assessment. Input data was obtained through an 18-month data collection campaign across the relevant stakeholders. A baseline 'business-as-usual' scenario is focused on throughout this study, and scope for optimisation is identified for each life cycle phase where applicable, accompanied by uncertainty analyses. Results show a total carbon input of 904.85 kg CO2e/tonne. Mitigating this, 521.88 kg CO2e/tonne is offset, resulting in a net carbon footprint of 382.97 kg CO2e/tonne with uncertainty ranges of -23.22 to +58.69 kg CO2e/tonne, normalised to 57.45 g CO2e/avocado grown in South Africa and sold in Europe. The environmental impacts of the avocado industry under consideration are largely mitigated by the "nature first" philosophy of the farming and logistics enterprises, which have made significant investments in reducing emissions. Sensitivity analyses indicate that implementing large-scale renewable energy, using alternative packaging instead of cardboard, and selling avocados unripened could further enable the farming enterprise to achieve Net Zero objectives. These measures could reduce baseline emissions from 382.97 kg CO2e/tonne to a theoretical -68.54 kg CO2e/tonne, representing a 117.9% decrease. Although this study does not quantify climate change impacts, qualitative analyses suggest that climate change will have a net negative effect on the avocado industry in South Africa. These regions, typically located in micro-climates, are projected to become wetter and warmer, adversely affecting crop phenology, pest control, road conditions, management complexity, farmer livelihoods, and food security. The study recommends large-scale implementation of the optimisation strategies identified to achieve Net Zero objectives and the development of proactive climate change mitigation strategies to enhance the resilience of avocado supply chains to future stressors. These insights are crucial for policymakers, industry stakeholders, and consumers aiming to promote sustainability in the avocado market.

Emerging concern of nano-pollution in agro-ecosystem: Flip side of nanotechnology

Nanomaterials (NMs) have proven to be a game-changer in agriculture, showcasing their potential to boost plant growth and safeguarding crops. The agricultural sector has widely adopted NMs, benefiting from their small size, high surface area, and optical properties to augment crop productivity and provide protection against various stressors. This is attributed to their unique characteristics, contributing to their widespread use in agriculture. Human exposure from various components of agro-environmental sectors (soil, crops) NMs residues are likely to upsurge with exposure paths may stimulates bioaccumulation in food chain. With the aim to achieve sustainability, nanotechnology (NTs) do exhibit its potentials in various domains of agriculture also have its flip side too. In this review article we have opted a fusion approach using bibliometric based analysis of global research trend followed by a holistic assessment of pros and cons i.e. toxicological aspect too. Moreover, we have also tried to analyse the current scenario of policy associated with the application of NMs in agro-environment.

The Antioxidant Defense System of Tomato (Solanum lycopersicum L.) Varieties under Drought Stress and upon Post-Drought Rewatering

Water shortage induces physiological, biochemical, and molecular alterations in plant leaves that play an essential role in plant adaptive response. The effects of drought and post-drought rewatering on the activity of antioxidant enzymes and levels of H2O2, phenolic compounds, ascorbic acid, and proline were studied in six local tomato (Solanum lycopersicum L.) varieties. The contents of H2O2 and ascorbic acid increased in all drought-exposed tomato plants and then decreased upon rewatering. The level of phenolic compounds also decreased in response to water shortage and then recovered upon rehydration, although the extent of this response was different in different varieties. The activities of ascorbate peroxidase (APX) and guaiacol peroxidase (POX) and the content of proline significantly increased in the drought-stressed plants and then decreased when the plants were rewatered. The activities of 8 constitutive APX isoforms and 2 constitutive POX isoforms varied upon exposure to drought and were observed after rewatering in all studied varieties. The information on the response of tomato plants to drought and subsequent rewatering is of great importance for screening and selection of drought-tolerant varieties, as well as for development of strategies for increasing plant productivity under adverse environmental conditions.

Comprehensive Analysis of Novel Synergistic Antioxidant Formulations: Insights into Pharmacotechnical, Physical, Chemical, and Antioxidant Properties

(1) Background: Oxidative stress plays a pivotal role in the pathogenesis of various diseases, including neurodegenerative disorders, cardiovascular diseases, cancer, and diabetes, highlighting the pressing need for effective antioxidant interventions. (2) Methods: In this study, we aimed to develop and characterise two novel antioxidant formulations, F3 and F4, as therapeutic interventions for oxidative stress-related conditions. (3) Results: The physicochemical characterisation, preformulation analysis, formulation, preparation of filling powders for capsules, capsule content evaluation, and antioxidant activity assessment of the two novel antioxidant formulations were assessed. These formulations comprise a combination of well-established antioxidants like quercetin, biotin, coenzyme Q10, and resveratrol. Through comprehensive testing, the formulations' antioxidant efficacy, stability, and potential synergistic interactions were evaluated. (4) Conclusions: The findings underscore the promising potential of these formulations as therapeutic interventions for oxidative stress-related disorders and highlight the significance of antioxidant interventions in mitigating their progression.

Complexity of responses to ionizing radiation in plants, and the impact on interacting biotic factors

In nature, plants are simultaneously exposed to different abiotic (e.g., heat, drought, and salinity) and biotic (e.g., bacteria, fungi, and insects) stresses. Climate change and anthropogenic pressure are expected to intensify the frequency of stress factors. Although plants are well equipped with unique and common defense systems protecting against stressors, they may compromise their growth and development for survival in such challenging environments. Ionizing radiation is a peculiar stress factor capable of causing clustered damage. Radionuclides are both naturally present on the planet and produced by human activities. Natural and artificial radioactivity affects plants on molecular, biochemical, cellular, physiological, populational, and transgenerational levels. Moreover, the fitness of pests, pathogens, and symbionts is concomitantly challenged in radiologically contaminated areas. Plant responses to artificial acute ionizing radiation exposure and laboratory-simulated or field chronic exposure are often discordant. Acute or chronic ionizing radiation exposure may occasionally prime the defense system of plants to better tolerate the biotic stress or could often exhaust their metabolic reserves, making plants more susceptible to pests and pathogens. Currently, these alternatives are only marginally explored. Our review summarizes the available literature on the responses of host plants, biotic factors, and their interaction to ionizing radiation exposure. Such systematic analysis contributes to improved risk assessment in radiologically contaminated areas.

Roles of endophytic fungi in medicinal plant abiotic stress response and TCM quality development

Medicinal plants, as medicinal materials and important drug components, have been used in traditional and folk medicine for ages. However, being sessile organisms, they are seriously affected by extreme environmental conditions and abiotic stresses such as salt, heavy metal, temperature, and water stresses. Medicinal plants usually produce specific secondary metabolites to survive such stresses, and these metabolites can often be used for treating human diseases. Recently, medicinal plants have been found to partner with endophytic fungi to form a long-term, stable, and win-win symbiotic relationship. Endophytic fungi can promote secondary metabolite accumulation in medicinal plants. The close relationship can improve host plant resistance to the abiotic stresses of soil salinity, drought, and extreme temperatures. Their symbiosis also sheds light on plant growth and active compound production. Here, we show that endophytic fungi can improve the host medicinal plant resistance to abiotic stress by regulating active compounds, reducing oxidative stress, and regulating the cell ion balance. We also identify the deficiencies and burning issues of available studies and present promising research topics for the future. This review provides guidance for endophytic fungi research to improve the ability of medicinal plants to resist abiotic stress. It also suggests ideas and methods for active compound accumulation in medicinal plants and medicinal material development during the response to abiotic stress.

Antioxidant production promotes defense mechanism and different gene expression level in Zea mays under abiotic stress

The growth and productivity of maize are severely affected by soil salinity. The crucial determinants for the future performance of plants are productive for seed germination and seedling establishment; however, both stages are liable to soil salinity. For grain, maize is an economically significant crop sensitive to abiotic stresses. However, little is known about defense responses by the salinity-induced antioxidant and oxidative stress in maize. In our work, the commercially available maize variety Raka-Poshi was grown in pots for 30 days under greenhouse conditions. To evaluate the salt-induced oxidative/antioxidant responses in maize for salt stress 0, 25, 50, 75, 100 and 150 mM concentrations, treatments were provided using sodium chloride (NaCl). All the biochemical indices were calculated under all NaCl concentrations, while drought was induced by up to 50% irrigation water. After 30 days of seed germination, the maize leaves were collected for the measurement of lipid peroxidase or malondialdehyde (MDA), glutathione reductase (GR), guaiacol peroxidase (GPOD), hydrogen peroxide (H2O2), superoxide dismutase (SOD), lipoxygenase (LOX), catalase (CAT), ascorbate peroxidase (APOD) and glutathione-S-transferase (GST). The results revealed a 47% reduction under 150 mM NaCl and 50% drought stress conditions. The results have shown that the successive increase of NaCl concentrations and drought caused an increase in catalase production. With successive increase in NaCl concentration and drought stress, lower levels of H2O2, SOD, and MDA were detected in maize leaves. The results regarding the morphology of maize seedlings indicated a successive reduction in the root length and shoot length under applications of salt and drought stress, while root-to-shoot weights were found to be increased under drought stress and decreased under salt stress conditions During gene expression analysis collectively indicate that, under drought stress conditions, the expression levels of all nine mentioned enzyme-related genes were consistently downregulated.

Integrating genes and metabolites: unraveling mango's drought resilience mechanisms

BACKGROUND

Mango (Mangifera indica L.) faces escalating challenges from increasing drought stress due to erratic climate patterns, threatening yields, and quality. Understanding mango's drought response mechanisms is pivotal for resilience and food security.

RESULTS

Our RNA-seq analyses unveil 12,752 differentially expressed genes linked to stress signaling, hormone regulation, and osmotic adjustment. Weighted Gene Co-expression Network Analysis identified three essential genes-WRKY transcription factor 3, polyamine oxidase 4, and protein MEI2-like 1-as drought defense components. WRKY3 having a role in stress signaling and defense validates its importance. Polyamine oxidase 4, vital in stress adaptation, enhances drought defense. Protein MEI2-like 1's significance emerges, hinting at novel roles in stress responses. Metabolite profiling illuminated Mango's metabolic responses to drought stress by presenting 990 differentially abundant metabolites, mainly related to amino acids, phenolic acids, and flavonoids, contributing to a deeper understanding of adaptation strategies. The integration between genes and metabolites provided valuable insights by revealing the correlation of WRKY3, polyamine oxidase 4 and MEI2-like 1 with amino acids, D-sphingnosine and 2,5-Dimethyl pyrazine.

CONCLUSIONS

This study provides insights into mango's adaptive tactics, guiding future research for fortified crop resilience and sustainable agriculture. Harnessing key genes and metabolites holds promise for innovative strategies enhancing drought tolerance in mango cultivation, contributing to global food security efforts.

Enzymes Involved in Antioxidant and Detoxification Processes Present Changes in the Expression Levels of Their Coding Genes under the Stress Caused by the Presence of Antimony in Tomato

Currently, there is an increasing presence of heavy metals and metalloids in soils and water due to anthropogenic activities. However, the biggest problem caused by this increase is the difficulty in recycling these elements and their high permanence in soils. There are plants with great capacity to assimilate these elements or make them less accessible to other organisms. We analyzed the behavior of Solanum lycopersicum L., a crop with great agronomic interest, under the stress caused by antimony (Sb). We evaluated the antioxidant response throughout different exposure times to the metalloid. Our results showed that the enzymes involved in the AsA-GSH cycle show changes in their expression level under the stress caused by Sb but could not find a relationship between the NITROSOGLUTATHIONE REDUCTASE (GSNOR) expression data and nitric oxide (NO) content in tomato roots exposed to Sb. We hypothesize that a better understanding of how these enzymes work could be key to develop more tolerant varieties to this kind of abiotic stress and could explain a greater or lesser phytoremediation capacity. Moreover, we deepened our knowledge about Glutathione S-transferase (GST) and Glutathione Reductase (GR) due to their involvement in the elimination of the xenobiotic component.

Telomere dynamics and oxidative stress in Arabidopsis grown in lunar regolith simulant

NASA envisions a future where humans establish a thriving colony on the Moon by 2050. Plants will be essential for this endeavor, but little is known about their adaptation to extraterrestrial bodies. The capacity to grow plants in lunar regolith would represent a major step towards this goal by minimizing the reliance on resources transported from Earth. Recent studies reveal that Arabidopsis thaliana can germinate and grow on genuine lunar regolith as well as on lunar regolith simulant. However, plants arrest in vegetative development and activate a variety of stress response pathways, most notably the oxidative stress response. Telomeres are hotspots for oxidative damage in the genome and a marker of fitness in many organisms. Here we examine A. thaliana growth on a lunar regolith simulant and the impact of this resource on plant physiology and on telomere dynamics, telomerase enzyme activity and genome oxidation. We report that plants successfully set seed and generate a viable second plant generation if the lunar regolith simulant is pre-washed with an antioxidant cocktail. However, plants sustain a higher degree of genome oxidation and decreased biomass relative to conventional Earth soil cultivation. Moreover, telomerase activity substantially declines and telomeres shorten in plants grown in lunar regolith simulant, implying that genome integrity may not be sustainable over the long-term. Overcoming these challenges will be an important goal in ensuring success on the lunar frontier.

Potential of UV-B radiation in drought stress resilience: A multidimensional approach to plant adaptation and future implications

The escalating impact of climate change and ultraviolet (UV) radiation is subjecting plants to unique combinations of UV-B and drought stress. These combined stressors could have additive, synergistic, or antagonistic effects, but the precise nature of these impacts remains uncertain, hampering our ability to predict plant adaptations approach towards stressors. Our analysis of various studies shows that UV-B or drought conditions detrimentally influence plant growth and health metrics by the enhanced generation of reactive oxygen species causing damage to lipids, proteins, carbohydrates and DNA. Further reducing biomass accumulation, plant height, photosynthetic efficiency, leaf area, and water transpiration, while enhancing stress-related symptoms. In response to UV-B radiation and drought stress, plants exhibit a notable up-regulation of specific acclimation-associated metabolites, including proline, flavonoids, anthocyanins, unsaturated fatty acids, and antioxidants. These metabolites play a pivotal role in conferring protection against environmental stresses. Their biosynthesis and functional roles are potentially modulated by signalling molecules such as hydrogen peroxide, abscisic acid, jasmonic acid, salicylic acid, and ethylene, all of which have associated genetic markers that further elucidate their involvement in stress response pathways. In comparison to single stress, the combination of UV-B and drought induces the plant defence responses and growth retardation which are less-than-additive. This sub-additive response, consistent across different study environments, suggests the possibility of a cross-resistance mechanism. Our outlines imply that the adverse effects of increased drought and UV-B could potentially be mitigated by cross-talk between UV-B and drought regimes utilizing a multidimensional approach. This crucial insight could contribute significantly to refining our understanding of stress tolerance in the face of ongoing global climate change.

Progress and prospects in harnessing wild relatives for genetic enhancement of salt tolerance in rice

Salt stress is the second most devastating abiotic stress after drought and limits rice production globally. Genetic enhancement of salinity tolerance is a promising and cost-effective approach to achieve yield gains in salt-affected areas. Breeding for salinity tolerance is challenging because of the genetic complexity of the response of rice plants to salt stress, as it is governed by minor genes with low heritability and high G × E interactions. The involvement of numerous physiological and biochemical factors further complicates this complexity. The intensive selection and breeding efforts targeted towards the improvement of yield in the green-revolution era inadvertently resulted in the gradual disappearance of the loci governing salinity tolerance and a significant reduction in genetic variability among cultivars. The limited utilization of genetic resources and narrow genetic base of improved cultivars have resulted in a plateau in response to salinity tolerance in modern cultivars. Wild species are an excellent genetic resource for broadening the genetic base of domesticated rice. Exploiting novel genes of underutilized wild rice relatives to restore salinity tolerance loci eliminated during domestication can result in significant genetic gain in rice cultivars. Wild species of rice, Oryza rufipogon and Oryza nivara, have been harnessed in the development of a few improved rice varieties like Jarava and Chinsura Nona 2. Furthermore, increased access to sequence information and enhanced knowledge about the genomics of salinity tolerance in wild relatives has provided an opportunity for the deployment of wild rice accessions in breeding programs, while overcoming the cross-incompatibility and linkage drag barriers witnessed in wild hybridization. Pre-breeding is another avenue for building material that are ready for utilization in breeding programs. Efforts should be directed towards systematic collection, evaluation, characterization, and deciphering salt tolerance mechanisms in wild rice introgression lines and deploying untapped novel loci to improve salinity tolerance in rice cultivars. This review highlights the potential of wild relatives of Oryza to enhance tolerance to salinity, track the progress of work, and provide a perspective for future research.

Selenium nanoparticles improved biochemical and physiological properties and antioxidant systems of savoury under drought stress

To investigate the effectiveness of selenium (Se) and Se nanoparticles (Se-NPs) in improving biochemical and physiological characteristics of savoury in drought stress conditions, a factorial experiment based on the completely randomised design with three replications was used. Results demonstrate that Se-NPs considerably enhanced several biochemical parameters, such as relative water content (RWC), antioxidant enzymes activity, and total soluble protein in drought and normal conditions. At the stress level from 100 to 40% of field capacity, a gradual decrease in chlorophyll and CARs contents was observed and under stress and normal conditions, the application of Se-NPs (10 mg L-1) led to an increase in the content of pigments. Total soluble protein, total phenolic and flavonoid contents showed significant increases in plants treated with Se-NPs under drought stress. Generally, the use of Se-NPs in drought stress conditions can be effective in improving the growth, biochemical, and physiological characteristics of savoury.

Exploring the nano-wonders: unveiling the role of Nanoparticles in enhancing salinity and drought tolerance in plants

Plants experience diverse abiotic stresses, encompassing low or high temperature, drought, water logging and salinity. The challenge of maintaining worldwide crop cultivation and food sustenance becomes particularly serious due to drought and salinity stress. Sustainable agriculture has significant promise with the use of nano-biotechnology. Nanoparticles (NPs) have evolved into remarkable assets to improve agricultural productivity under the robust climate alteration and increasing drought and salinity stress severity. Drought and salinity stress adversely impact plant development, and physiological and metabolic pathways, leading to disturbances in cell membranes, antioxidant activities, photosynthetic system, and nutrient uptake. NPs protect the membrane and photosynthetic apparatus, enhance photosynthetic efficiency, optimize hormone and phenolic levels, boost nutrient intake and antioxidant activities, and regulate gene expression, thereby strengthening plant's resilience to drought and salinity stress. In this paper, we explored the classification of NPs and their biological effects, nanoparticle absorption, plant toxicity, the relationship between NPs and genetic engineering, their molecular pathways, impact of NPs in salinity and drought stress tolerance because the effects of NPs vary with size, shape, structure, and concentration. We emphasized several areas of research that need to be addressed in future investigations. This comprehensive review will be a valuable resource for upcoming researchers who wish to embrace nanotechnology as an environmentally friendly approach for enhancing drought and salinity tolerance.

Ancestors in the Extreme: A Genomics View of Microbial Diversity in Hypersaline Aquatic Environments

The origin of eukaryotic cells, and especially naturally occurring syncytial cells, remains debatable. While a majority of our biomedical research focuses on the eukaryotic result of evolution, our data remain limiting on the prokaryotic precursors of these cells. This is particularly evident when considering extremophile biology, especially in how the genomes of organisms in extreme environments must have evolved and adapted to unique habitats. Might these rapidly diversifying organisms have created new genetic tools eventually used to enhance the evolution of the eukaryotic single nuclear or syncytial cells? Many organisms are capable of surviving, or even thriving, in conditions of extreme temperature, acidity, organic composition, and then rapidly adapt to yet new conditions. This study identified organisms found in extremes of salinity. A lake and a nearby pond in the Ethiopian Rift Valley were interrogated for life by sequencing the DNA of populations of organism collected from the water in these sites. Remarkably, a vast diversity of microbes were identified, and even though the two sites were nearby each other, the populations of organisms were distinctly different. Since these microbes are capable of living in what for humans would be inhospitable conditions, the DNA sequences identified should inform the next step in these investigations; what new gene families, or modifications to common genes, do these organisms employ to survive in these extreme conditions. The relationship between organisms and their environment can be revealed by decoding genomes of organisms living in extreme environments. These genomes disclose new biological mechanisms that enable life outside moderate environmental conditions, new gene functions for application in biotechnology, and may even result in identification of new species. In this study, we have collected samples from two hypersaline sites in the Danakil depression, the shorelines of Lake As'ale and an actively mixing salt pond called Muda'ara (MUP), to identify the microbial community by metagenomics. Shotgun sequencing was applied to high density sampling, and the relative abundance of Operational Taxonomic Units (OTUs) was calculated. Despite the broad taxonomic similarities among the salt-saturated metagenomes analyzed, MUP stood out from Lake As'ale samples. In each sample site, Archaea accounted for 95% of the total OTUs, largely to the class Halobacteria. The remaining 5% of organisms were eubacteria, with an unclassified strain of Salinibacter ruber as the dominant OTU in both the Lake and the Pond. More than 40 different genes coding for stress proteins were identified in the three sample sites of Lake As'ale, and more than 50% of the predicted stress-related genes were associated with oxidative stress response proteins. Chaperone proteins (DnaK, DnaJ, GrpE, and ClpB) were predicted, with percentage of query coverage and similarities ranging between 9.5% and 99.2%. Long reads for ClpB homologous protein from Lake As'ale metagenome datasets were modeled, and compact 3D structures were generated. Considering the extreme environmental conditions of the Danakil depression, this metagenomics dataset can add and complement other studies on unique gene functions on stress response mechanisms of thriving bio-communities that could have contributed to cellular changes leading to single and/or multinucleated eukaryotic cells.

Effects of the Pesticide Carbofuran on Two Species of Chlorophyceae (Desmodesmus communis and Pseudopediastrum boryanum) and Their Pesticide Bioremediation Ability

Carbofuran is one of the most toxic broad-spectrum pesticides. We evaluated the effects of carbofuran on two species of microalgae, Pseudopediastrum boryanum and Desmodesmus communis, through measurements of cell viability, biomass, chlorophyll content, and the production of reactive oxygen species (ROS). The ability of these algae to remove carbofuran dissolved in the media was also determined. For the evaluations, both microalgae species were exposed to carbofuran (FURADAN 350 SC®) at concentrations of 100, 1000, and 10,000 µg L-1 for 7 days. Algae cell viability and chlorophyll-a concentration were not affected by the presence of carbofuran. Both species grew when exposed to the pesticide; however, the microalgae D. communis grew less than its respective control when exposed to the highest concentration (10,000 µg L-1 of carbofuran), indicating an adverse effect of the pesticide on this species. A significant increase in ROS production was observed in D. communis and P. boryanum when exposed to the highest concentration tested. The microalgae P. boryanum completely removed carbofuran in the media within 2 days, regardless of the concentration, whereas D. communis achieved the same result only after 5 days of exposure. Growth inhibition was observed only until the disappearance of carbofuran from the media. The present study suggests the use of microalgae, mainly P. boryanum, as potential tools for the remediation of environments contaminated by carbofuran because of their resistance to the insecticide and their ability to remove it rapidly from water. Environ Toxicol Chem 2024;00:1-12. © 2023 SETAC.

Screening some pine species from North America and dried zones of western Asia for drought stress tolerance in terms of nutrients status, biochemical and physiological characteristics

Drought due to climate change or reduced precipitation is one of the main factors limiting the growth and establishment of plants and is one of the most critical challenges facing humans. To investigate the effect of different levels of drought stress on some pine species, this research was carried out as a factorial experiment using two factors and a completely randomized design. It included five populations of four pine species (Pinus brutia Ten. var. eldarica, P. nigra Arnold, P. mugo, and P. banksiana Lamb (including populations 8310055 and 8960049), and three levels of irrigation (100%, 75%, or 50% FC, denoted as normal, mild or intense drought stress, respectively) with three replicates. The findings showed that, photosynthetic pigments, relative water content, visual quality, the content of nutrients, protein content, and fresh and dry weight all decreased significantly when plants were exposed to intense drought stress. However, raised proline levels, electrolyte leakage percentage, soluble sugars levels, and antioxidant enzyme activity. We detected a decline in most growth traits when comparing mild drought stress conditions to normal irrigation, yet acceptable quality seedlings when compared to intense drought stress. Intense drought stress had a substantial impact on many pine seedlings. PCA results showed that among different pine species, the level of resistance to drought is as follows: P. mugo> P. brutia var. eldarica> P. nigra> P. banksiana 8310055> P. banksiana 8960049. Our novel finding was that, P. mugo is a resistant species in arid and semi-arid regions, and P. banksiana species, especially its population of 8960049, is sensitive.

Effects of Exogenous Ethanol Treatment in Nutrient Solution on Growth and Secondary Metabolite Contents of Three Herb Species in an Indoor Vertical Farming System

This study aimed to explore the possibility of exogenous ethanol treatment as a technology to regulate the growth and the synthesis of secondary metabolites in herbaceous plants. After transplantation, sweet basil, Korean mint, and sweet wormwood were cultivated in a controlled vertical farming system and consistently exposed to exogenous ethanol at concentrations of 0, 0.5, 1, 2, 4, and 8 mM. Their growth parameters, antioxidant activity, and secondary metabolite contents were Everything is fine. measured to investigate the effects of the exogenous ethanol treatment on the three plants. The low-concentration ethanol treatments increased the shoot dry weight of the sweet basil and sweet wormwood compared to that of the control. As the ethanol concentration increased, the shoot fresh weight and leaf area in the sweet basil and Korean mint decreased compared to those of the control (0 mM). The DPPH (2,2-Diphenyl-1-picrylhydrazyl) radical scavenging activity and total phenolic content of the three plants increased with the ethanol concentration, while the total flavonoid content did not demonstrate a significant trend. The chlorophyll and carotenoids of the basil showed no apparent concentration-dependent trends; however, the chlorophyll and carotenoids of the Korean mint and sweet wormwood decreased with high ethanol concentrations. Moreover, the antioxidant enzyme activity increased with high ethanol concentrations, indicating that high ethanol concentrations induce oxidative stress in plants.

Application of bio-organic amendments improves soil quality and yield of fennel (Foeniculum vulgare Mill.) plants in saline calcareous soil

The impact of bio-organic amendments on crop production is poorly understood in saline calcareous soils. The aim in the present study was to determine the effects of the application of organic manure along with lactic acid bacteria (LAB) on soil quality, and morpho-physio-biochemical responses, seed yield (SY) and essential oil yield (EOY) of fennel plants (Foeniculum vulgare Mill.) grown in saline calcareous soils. Eight treatments of farmyard manure (FM) or poultry manure (PM) individually or combined with Lactobacillus plantarum (Lp) and/or Lactococcus lactis (Ll) were applied to saline calcareous soil in two growing seasons. Either FM or PM combined with LAB had beneficial effects on lowering ECe, pH and bulk density and increasing total porosity, organic matter, and water and nutrient retention capacities in addition to total bacterial population in the soil. Growth, nutrient uptake, SY and EOY of plants were also enhanced when fennel seeds were inoculated with Lp and/or Ll and the soil was amended with any of the organic manures under unfavorable conditions. Compared to control (no bio-organic amendments), FM + Lp + Lt or PM + Lp + Lt treatment signficantlly (P ≤ 0.05) increased plant height by 86.2 or 65.0%, total chlorophyll by 73 or 50%, proline by 35 or 45%, glutathione by 100 or 138%, SY by 625 or 463% and EOY by 300 or 335%, respectively, in fennel plants. Co-application of the naturally occurring microorganisms (i.e., LAB) and organically-derived, nutrient-rich fertilizer (i.e., FM or PM) is recommended to improve yield of fennel plants in saline calcareous soils.

Health impact assessment after Danio rerio long-term exposure to environmentally relevant concentrations of metformin and guanylurea

The antidiabetic drug metformin (MET) and its metabolite guanylurea (GUA) have been frequently and ubiquitously detected in surface water. Consequently, there has been a consistent rise in studying the toxicity of MET and GUA in fish over the past decade. Nonetheless, it is noteworthy that no study has assessed the harmful effects both compounds might trigger on fish blood and organs after chronic exposure. Taking into consideration the data above, our research strived to accomplish two primary objectives: Firstly, to assess the effect of comparable concentrations of MET and GUA (1, 40, 100 μg/L) on the liver, gills, gut, and brain of Danio rerio after six months of flow-through exposure. Secondly, to compare the outcomes to identify which compound prompts more significant oxidative stress and apoptosis in organs and blood parameter alterations. Herein, findings indicate that both compounds induced oxidative damage and increased the expression of genes associated with apoptosis (bax, bcl2, p53, and casp3). Chronic exposure to MET and GUA also generated fluctuations in glucose, creatinine, phosphorus, liver enzymes, red and white blood count, hemoglobin, and hematocrit levels. The observed biochemical changes indicate that MET and GUA are responsible for inducing hepatic damage in fish, whereas hematological alterations suggest that both compounds cause anemia. Considering GUA altered to a more considerable extent the values of all endpoints compared to the control group, it is suggested transformation product GUA is more toxic than MET. Moreover, based on the above evidence, it can be inferred that a six-month exposure to MET and GUA can impair REDOX status and generate apoptosis in fish, adversely affecting their essential organs' functioning.

Application of neem waste vermicompost in compensating nematode induced stress and upregulating physiological markers of tomato plants under glass house conditions after 10 days of exposure

Farming, food processing, animal husbandry and other agro-based activities contribute to global environmental degradation by producing millions of tons of organic and inorganic solid waste. In terms of sustainable agriculture, agricultural waste management and conversion into useful products are essential. In addition, plants are facing various kinds of biotic stress, which ultimately affects their defense system. Altered defense systems in plants ultimately lead to the death of plants and a reduction in crop production. The present study is designed to keep the abovementioned fact in mind, which mainly focuses on the reuse of agricultural waste and its application to the antioxidant potential and structural components of tomato plants during nematode stress. In the present study, neem leaves were collected and mixed with cattle dung for the preparation of vermicompost. Then, tomato seeds were pre-treated with vermicompost extract before being germinated in earthen pots. After germination, they were transplanted to separate pots and inoculated with freshly hatched juveniles of Meloidogyne incognita. The experiments were conducted for 10 days under glass house conditions, and after that, plants were harvested and various physiological (antioxidant capacity, percent electrolyte leakage) and structural markers (carbohydrate content, Fourier transform infrared spectroscopy) were analyzed. Results revealed that all physico-chemical properties make vermicompost superior as compared to soil and pre-compost material. Further, nematode stress leads to altered physiological and structural markers as compared to uninfected seedlings. However, treatment with vermicompost significantly increases carbohydrate content and antioxidative capacity in a concentration dependent manner. In addition, electrolyte leakage was found to be decrease with an increase in the concentration of vermicompost. All these findings conclude that vermicompost has strong potential to limit the damage caused by nematodes and boost the antioxidant potential of the host plants. Further, this study provides strong evidence for using vermicompost as an eco-friendly alternative to chemical nematicides and a potential strategy for agricultural waste management. This is the first study in which the tomato plant's structural and physiological markers were assessed during nematode stress after being supplemented with vermicompost under glass house conditions for an initial 10 days of nematode exposure.

Germination of Pisum sativum L. Seeds Is Associated with the Alternative Respiratory Pathway

The alternative oxidase (AOX) is a ubiquinol oxidase with a crucial role in the mitochondrial alternative respiratory pathway, which is associated with various processes in plants. In this study, the activity of AOX in pea seed germination was determined in two pea cultivars, 'Maravilha d'América' (MA) and 'Torta de Quebrar' (TQ), during a germination trial using cytochrome oxidase (COX) and AOX inhibitors [rotenone (RT) and salicylic hydroxamic acid (SHAM), respectively]. Calorespirometry was used to assess respiratory changes during germination. In both cultivars, SHAM had a greater inhibitory effect on germination than RT, demonstrating the involvement of AOX in germination. Although calorespirometry did not provide direct information on the involvement of the alternative pathway in seed germination, this methodology was valuable for distinguishing cultivars. To gain deeper insights into the role of AOX in seed germination, the AOX gene family was characterized, and the gene expression pattern was evaluated. Three PsAOX members were identified-PsAOX1, PsAOX2a and PsAOX2b-and their expression revealed a marked genotype effect. This study emphasizes the importance of AOX in seed germination, contributing to the understanding of the role of the alternative respiratory pathway in plants.

A review on toxicity of nanomaterials in agriculture: Current scenario and future prospects

Phytonanotechnology plays a crucial part in the production of good quality and high-yield food. It can also alter the plant's production systems, hence permitting the efficient, controlled and stable release of agrochemicals such as fertilizers and pesticides. An advanced understanding of nanomaterials interaction with plant responses like localization and uptake, etc. could transfigure the production of crops with high disease resistance and efficient nutrients utilization. In agriculture, the use of nanomaterials has gained acceptance due to their wide-range applications. However, their toxicity and bioavailability are the major hurdles for their massive employment. Undoubtedly, nanoparticles positively influence seeds germination, growth and development, stress management and post-harvest handling of vegetables and fruits. These nanoparticles may also cause toxicity in plants through oxidative stress by generation of excessive reactive oxygen species thus affecting the cellular biomolecules and targeting different channels. Nanoparticles have shown to exert various effects on plants that are mainly affected by various attributes such as physicochemical features of nanomaterials, coating materials for nanoparticles, type of plant, growth stages and growth medium for plants. This article discusses the interaction, accretion and toxicity of nanomaterials in plants. The factors inducing nanotoxicity and the mechanisms followed by nanomaterials causing toxicity are also instructed. At the end, detoxification mechanism of plant is also presented.

Molecular, biochemical and metabolomics analyses reveal constitutive and pathogen-induced defense responses of two sugarcane contrasting genotypes against leaf scald disease

Leaf scald caused by the bacteria Xanthomonas albilineans is one of the major concerns to sugarcane production. To breed for resistance, mechanisms underlying plant-pathogen interaction need deeper investigations. Herein, we evaluated sugarcane defense responses against X. albilineans using molecular and biochemical approaches to assess pathogen-triggered ROS, phytohormones and metabolomics in two contrasting sugarcane genotypes from 0.5 to 144 h post-inoculation (hpi). In addition, the infection process was monitored using TaqMan-based quantification of X. albilineans and the disease symptoms were evaluated in both genotypes after 15 d post-inoculation (dpi). The susceptible genotype presented a response to the infection at 0.5 hpi, accumulating defense-related metabolites such as phenolics and flavonoids with no significant defense responses thereafter, resulting in typical symptoms of leaf scald at 15 dpi. The resistant genotype did not respond to the infection at 0.5 hpi but constitutively presented higher levels of salicylic acid and of the same metabolites induced by the infection in the susceptible genotype. Moreover, two subsequent pathogen-induced metabolic responses at 12 and 144 hpi were observed only in the resistant genotype in terms of amino acids, quinic acids, coumarins, polyamines, flavonoids, phenolics and phenylpropanoids together with an increase of hydrogen peroxide, ROS-related genes expression, indole-3-acetic-acid and salicylic acid. Multilevel approaches revealed that constitutive chemical composition and metabolic reprogramming hampers the development of leaf scald at 48 and 72 hpi, reducing the disease symptoms in the resistant genotype at 15 dpi. Phenylpropanoid pathway is suggested as a strong candidate marker for breeding sugarcane resistant to leaf scald.

Current Scenario and Future Prospects of Endophytic Microbes: Promising Candidates for Abiotic and Biotic Stress Management for Agricultural and Environmental Sustainability

Globally, substantial research into endophytic microbes is being conducted to increase agricultural and environmental sustainability. Endophytic microbes such as bacteria, actinomycetes, and fungi inhabit ubiquitously within the tissues of all plant species without causing any harm or disease. Endophytes form symbiotic relationships with diverse plant species and can regulate numerous host functions, including resistance to abiotic and biotic stresses, growth and development, and stimulating immune systems. Moreover, plant endophytes play a dominant role in nutrient cycling, biodegradation, and bioremediation, and are widely used in many industries. Endophytes have a stronger predisposition for enhancing mineral and metal solubility by cells through the secretion of organic acids with low molecular weight and metal-specific ligands (such as siderophores) that alter soil pH and boost binding activity. Finally, endophytes synthesize various bioactive compounds with high competence that are promising candidates for new drugs, antibiotics, and medicines. Bioprospecting of endophytic novel secondary metabolites has given momentum to sustainable agriculture for combating environmental stresses. Biotechnological interventions with the aid of endophytes played a pivotal role in crop improvement to mitigate biotic and abiotic stress conditions like drought, salinity, xenobiotic compounds, and heavy metals. Identification of putative genes from endophytes conferring resistance and tolerance to crop diseases, apart from those involved in the accumulation and degradation of contaminants, could open new avenues in agricultural research and development. Furthermore, a detailed molecular and biochemical understanding of endophyte entry and colonization strategy in the host would better help in manipulating crop productivity under changing climatic conditions. Therefore, the present review highlights current research trends based on the SCOPUS database, potential biotechnological interventions of endophytic microorganisms in combating environmental stresses influencing crop productivity, future opportunities of endophytes in improving plant stress tolerance, and their contribution to sustainable remediation of hazardous environmental contaminants.

A Genome-Wide Identification and Comparative Analysis of the Heavy-Metal-Associated Gene Family in Cucurbitaceae Species and Their Role in Cucurbita pepo under Arsenic Stress

The heavy-metal-associated (HMA) proteins are a class of PB1-type ATPases related to the intracellular transport and detoxification of metals. However, due to a lack of information regarding the HMA gene family in the Cucurbitaceae family, a comprehensive genome-wide analysis of the HMA family was performed in ten Cucurbitaceae species: Citrullus amarus, Citrullus colocynthis, Citrullus lanatus, Citrullus mucosospermus, Cucumis melo, Cucumis sativus, Cucurbita maxima, Cucurbita moschata, Cucurbita pepo, and Legenaria siceraria. We identified 103 Cucurbit HMA proteins with various members, ranging from 8 (Legenaria siceraria) to 14 (Cucurbita pepo) across species. The phylogenetic and structural analysis confirmed that the Cucurbitaceae HMA protein family could be further classified into two major clades: Zn/Co/Cd/Pb and Cu/Ag. The GO-annotation-based subcellular localization analysis predicted that all HMA gene family members were localized on membranes. Moreover, the analysis of conserved motifs and gene structure (intron/exon) revealed the functional divergence between clades. The interspecies microsynteny analysis demonstrated that maximum orthologous genes were found between species of the Citrullus genera. Finally, nine candidate HMA genes were selected, and their expression analysis was carried out via qRT-PCR in root, leaf, flower, and fruit tissues of C. pepo under arsenic stress. The expression pattern of the CpeHMA genes showed a distinct pattern of expression in root and shoot tissues, with a remarkable expression of CpeHMA6 and CpeHMA3 genes from the Cu/Ag clade. Overall, this study provides insights into the functional analysis of the HMA gene family in Cucurbitaceae species and lays down the basic knowledge to explore the role and mechanism of the HMA gene family to cope with arsenic stress conditions.

Proline concentrations in seedlings of woody plants change with drought stress duration and are mediated by seed characteristics: a meta-analysis

Proline accumulation represents one of mechanisms used by plants to prevent the adverse consequences of water stress. The effects of increased proline levels in response to drought differ among species. Trees are exposed to the long-term effects of climate change. The reproductive success of species in a specific environment depends on the functional trait of tree seeds. We conducted a meta-analysis to evaluate the effects of drought stress on the proline concentrations in seedling leaf tissues of woody plant species and their relationships to drought duration, seed mass, seed category and coniferous/deciduous classification. Drought duration exhibited a nonlinear effect on proline accumulations. The drought effect on proline accumulations is greater for deciduous than for coniferous species and is higher for orthodox seed species than for recalcitrant. The seedlings of large-seeded species showed greater effect sizes than those of small-seeded species. Our results suggest that there is an optimum level at which proline accumulations under the influence of drought are the highest. A link between seed functional traits, as well as the coniferous/deciduous classification, and proline concentrations in tree seedlings during water stress were determined for the first time. Proline may help to identify high-quality seeds of trees used for reforestation.

Genome-Wide Identification of Bilberry WRKY Transcription Factors: Go Wild and Duplicate

WRKY transcription factor genes compose an important family of transcriptional regulators that are present in several plant species. According to previous studies, these genes can also perform important roles in bilberry (Vaccinium myrtillus L.) metabolism, making it essential to deepen our understanding of fruit ripening regulation and anthocyanin biosynthesis. In this context, the detailed characterization of these proteins will provide a comprehensive view of the functional features of VmWRKY genes in different plant organs and in response to different intensities of light. In this study, the investigation of the complete genome of the bilberry identified 76 VmWRKY genes that were evaluated and distributed in all twelve chromosomes. The proteins encoded by these genes were classified into four groups (I, II, III, and IV) based on their conserved domains and zinc finger domain types. Fifteen pairs of VmWRKY genes in segmental duplication and four pairs in tandem duplication were detected. A cis element analysis showed that all promoters of the VmWRKY genes contain at least one potential cis stress-response element. Differential expression analysis of RNA-seq data revealed that VmWRKY genes from bilberry show preferential or specific expression in samples. These findings provide an overview of the functional characterization of these proteins in bilberry.

Development of yeast and microalgae consortium biofilm growth system for biofuel production

Background

The current study aimed to develop a laboratory-scale biofilm photobioreactor system for biofuel production.

Scope & Approach

During the investigation, Jute was discovered to be the best, cheap, hairy, open-pored supporting material for biofilm formation. Microalgae & yeast consortium was used in this study for biofilm formation.

Conclusion

The study identified microalgae and yeast consortium as a promising choice and ideal partners for biofilm formation with the highest biomass yield (47.63 ± 0.93 g/m2), biomass productivity (4.39 ± 0.29 to 7.77 ± 0.05 g/m2/day) and lipid content (36%) over 28 days cultivation period, resulting in a more sustainable and environmentally benign fuel that could become a reality in the near future.

Melatonin supplementation combats nickel-induced phytotoxicity in Trigonella foenum-graecum L. plants through metal accumulation reduction, upregulation of NO generation, antioxidant defence machinery and secondary metabolites

Nickel (Ni) at a toxic level (80 mg kg-1 of soil) adversely affects the crop performance of fenugreek (Trigonella foenum-graecum L.). Melatonin (MEL), a potent plant growth regulator, is ascribed to offer promising roles in heavy metal stress alleviation. In this study, different doses viz. 0, 25, 50, 75 and 100 μM of MEL were administered to plants through foliage under normal and Ni-stress conditions. The experiment unveiled positive roles of MEL in enhancing root-shoot lengths, fresh-dry weights, seed yield and restoring photosynthetic efficiency assessed in terms of higher Fv/Fm, YII, qP, and lower NPQ values in plants exposed to Ni (80 mg kg-1). MEL supplementation (at 75 μM) effectively restricted Ni accumulation and regulated oxidative stress via modulation of MDA, O2-, H2O2 and NO generation, most prominently. Besides, MEL at 75 μM more conspicuously perked up the activities of antioxidant enzymes like SOD, POX, CAT and APX by 15.7, 20.0, 14.5 and 16.5% higher than the Ni-exposed plants for effective ROS scavenging. Likewise, MEL at 75 μM also efficiently counteracted Ni-generated osmotic stress, through an upscaled accumulation of proline (19.6%) along with the enhancement in the concentration of total phenols (13.6%), total tannins (11.2%), total flavonoids (25.5%) and total alkaloids (19.2%) in plant's leaves. Furthermore, under 80 mg kg-1 Ni stress, MEL at 75 μM improved the seed's trigonelline content by 40.1% higher compared to Ni-disturbed plants, upgrading the pharmacological actions of the plant. Thus, the present study deciphers the envisaged roles of MEL in the alleviation of Ni stress in plants to enhance overall crop productivity.

rGO outperforms GO in generating oxidative stress and DNA strand breaks in zebrafish liver cells

Graphene oxide (GO) and reduced graphene oxide (rGO) are both widely applicable and there is a massive production throughout the world which imply in inevitable contamination in the aquatic environment by their wastes. Nevertheless, information about their interaction at the cellular level in fish is still scarce. We investigated the metabolic activity, reactive oxygen species (ROS) production, responses of antioxidant defenses, and total antioxidant capacity (TAC) as well as oxidative stress and DNA integrity in zebrafish liver cells (ZFL) exposed to (0.001, 0.01, 0.1 and 1 µg mL-1) of GO and rGO after two exposure period (24 and 72 h). Higher ROS production and no significant changes in the antioxidant defenses resulted in lipid peroxidation in cells exposed to rGO. Cells exposed to GO increased the activity of antioxidant defenses sustaining the TAC and avoiding lipid peroxidation. Comet assay showed that both, GO and rGO, caused DNA strand breaks after 24 h of exposure; however, only rGO caused DNA damage after 72 h of exposure. The exposure to rGO was significantly more harmful to ZFL cells than GO, even at very low concentrations. The cells showed a high capacity to neutralize ROS induced by GO preventing genotoxic effects and metabolic activity, thus sustaining cell viability. The time of exposure had different impacts for both nanomaterials, GO caused more changes in 24 h showing recovery after 72 h, while cells exposed to rGO were jeopardized at both exposure times. These results indicate that the reduction of GO by removal of the oxygen functional groups (rGO) increased toxicity leading to adverse effects in the cells, even at very low concentrations.

Integrated approaches for increasing plant yield under salt stress

Salt stress affects large cultivated areas worldwide, thus causing remarkable reductions in plant growth and yield. To reduce the negative effects of salt stress on plant growth and yield, plant hormones, nutrient absorption, and utilization, as well as developing salt-tolerant varieties and enhancing their morpho-physiological activities, are some integrative approaches to coping with the increasing incidence of salt stress. Numerous studies have been conducted to investigate the critical impacts of these integrative approaches on plant growth and yield. However, a comprehensive review of these integrative approaches, that regulate plant growth and yield under salt stress, is still in its early stages. The review focused on the major issues of nutrient absorption and utilization by plants, as well as the development of salt tolerance varieties under salt stress. In addition, we explained the effects of these integrative approaches on the crop's growth and yield, illustrated the roles that phytohormones play in improving morpho-physiological activities, and identified some relevant genes involve in these integrative approaches when the plant is subjected to salt stress. The current review demonstrated that HA with K enhance plant morpho-physiological activities and soil properties. In addition, NRT and NPF genes family enhance nutrients uptake, NHX1, SOS1, TaNHX, AtNHX1, KDML, RD6, and SKC1, maintain ion homeostasis and membrane integrity to cope with the adverse effects of salt stress, and sd1/Rht1, AtNHX1, BnaMAX1s, ipal-1D, and sft improve the plant growth and yield in different plants. The primary purpose of this investigation is to provide a comprehensive review of the performance of various strategies under salt stress, which might assist in further interpreting the mechanisms that plants use to regulate plant growth and yield under salt stress.

Soybean Plants Exposed to Low Concentrations of Potassium Iodide Have Better Tolerance to Water Deficit through the Antioxidant Enzymatic System and Photosynthesis Modulation

Water deficit inhibits plant growth by affecting several physiological processes, which leads to the overproduction of reactive oxygen species (ROS) that may cause oxidative stress. In this regard, iodine (I) is already known to possibly enhance the antioxidant defense system of plants and promote photosynthetic improvements under adverse conditions. However, its direct effect on water deficit responses has not yet been demonstrated. To verify the efficiency of I concerning plant tolerance to water deficit, we exposed soybean plants to different concentrations of potassium iodide (KI) fed to pots with a nutrient solution and subsequently submitted them to water deficit. A decline in biomass accumulation was observed in plants under water deficit, while exposure to KI (10 and 20 μmol L^-1) increased plant biomass by an average of 40%. Furthermore, exposure to KI concentrations of up to 20 μM improved gas exchange (~71%) and reduced lipid peroxidation. This is related to the higher enzymatic antioxidant activities found at 10 and 20 μM KI concentrations. However, when soybean plants were properly irrigated, KI concentrations greater than 10 μM promoted negative changes in photosynthetic efficiency, as well as in biomass accumulation and partition. In sum, exposure of soybean plants to 10 μM KI improved tolerance to water deficit, and up to this concentration, there is no evidence of phytotoxicity in plants grown under adequate irrigation.

Lipids and volatile organic compounds in sesame seeds and their relationships with environmental temperature-induced stress

Sesame seeds contain several lipids and fragrances that offer health benefits. However, no studies have reported a relationship between the lipids or flavor compounds of sesame seeds and environmental factors. In this study, we aimed to identify this relationship by analyzing the contents of lipidic and flavor compounds in fifteen genotypes of sesame seeds grown in two cultivation regions (Jeonju and Miryang) and years (2018 and 2019). Herein, 17 lipids and 62 flavor compounds were detected. Multivariate statistical analyses revealed that the cultivation year had a larger influence on the contents of lipidic and flavor compounds than the cultivation region and genotype. Furthermore, heat stress due to high cultivation temperature in 2018 caused the accumulation of sugar and secondary metabolites, increased flavor-related substances, and inhibited the degradation of fatty acids. Our study is the first to demonstrate the metabolic changes in lipids and flavor components of sesame in response to environmental temperature changes affected by different cultivation years. Therefore, this study provides guidance for the cultivation of commercially advantageous sesame seeds in improving the quality of sesame seeds and their products.

Environmental impacts of air pollution and its abatement by plant species: A comprehensive review

Air pollution is one of the major global environmental issues urgently needed attention for its control through sustainable approaches. The release of air pollutants from various anthropogenic and natural processes imposes serious threats to the environment and human health. The green belt development using air pollution-tolerant plant species has become popular approach for air pollution remediation. Plants' biochemical and physiological attributes, especially relative water content, pH, ascorbic acid, and total chlorophyll content, are taken into account for assessing air pollution tolerance index (APTI). In contrast, anticipated performance index (API) is assessed based on socio-economic characteristics including "canopy structure, type, habit, laminar structure, economic value and APTI score" of plant species. Based on previous work, plants with high dust-capturing capacity are identified in Ficus benghalensis L. (0.95 to 7.58 mg/cm2), and highest overall PM accumulation capacity was observed in Ulmus pumila L. (PM10 = 72 µg/cm2 and PM2.5 = 70 µg/cm2) in the study from different regions. According to APTI, the plant species such as M. indica (11 to 29), Alstonia scholaris (L.) R. Br. (6 to 24), and F. benghalensis (17 to 26) have been widely reported as high air pollution-tolerant species and good to best performer in terms of API at different study sites. Statistically, previous studies show that ascorbic acid (R2 = 0.90) has good correlation with APTI among all the parameters. The plant species with high pollution tolerance capacity can be recommended for future plantation and green belt development.

Exogenous abscisic acid fine-tunes heavy metal accumulation and plant's antioxidant defence mechanism to optimize crop performance and secondary metabolite production in Trigonella foenum-graecum L. under nickel stress

Nickel (Ni) contamination of farming soil has become currently a recurring global menace to agriculture crop productivity. The purpose of the present study was to investigate the putative contributions of abscisic acid (ABA) to extemporize Ni tolerance in Trigonella foenum-graecum L. (fenugreek) plants. The outcomes of this study exposed that exogenous supplementation of ABA at 10, 20, 40 and 80 µM considerably enhanced the growth and physiological attributes of fenugreek under 80 mg Ni kg^-1 soil, however, 40 µM of ABA exhibited the best results under normal and Ni-stressed conditions. ABA-mediated Ni tolerance was marked by reductions in Ni accumulation and consequent lowering of reactive oxygen species (ROS) like hydrogen peroxide and superoxide radicals. Contrarily, NO (nitric oxide) level increased in response to ABA application under Ni stress conditions, accompanied by promoted antioxidant activities through improved levels of secondary metabolites, proline, and perked-up ROS-detoxification enzymes activities. Exogenous ABA at 40 µM concentration applied to Ni-exposed plants (80 mg Ni kg^-1 soil) improved the total content of alkaloids, phenolics, flavonoids and tannins by 14.3%, 10.2%, 15.4% and 7.0%, respectively, over Ni-stressed plants alone. Additionally, seed trigonelline content imparting several pharmacological actions to the fenugreek plant exhibited a remarkable escalation upto 3.6 and 2.6 mg g^-1 DW under '40 µM ABA' and '40 µM ABA + 80 mg Ni kg^-1 soil' treatments, respectively. The findings of the study suggest that ABA plays a key role in enhancing the overall performance of the fenugreek crop under excessive Ni stress.

Recent progress on the microbial mitigation of heavy metal stress in soybean: overview and implications

Plants are adapted to defend themselves through programming, reprogramming, and stress tolerance against numerous environmental stresses, including heavy metal toxicity. Heavy metal stress is a kind of abiotic stress that continuously reduces various crops' productivity, including soybeans. Beneficial microbes play an essential role in improving plant productivity as well as mitigating abiotic stress. The simultaneous effect of abiotic stress from heavy metals on soybeans is rarely explored. Moreover, reducing metal contamination in soybean seeds through a sustainable approach is extremely needed. The present article describes the initiation of heavy metal tolerance mediated by plant inoculation with endophytes and plant growth-promoting rhizobacteria, the identification of plant transduction pathways via sensing annotation, and contemporary changes from molecular to genomics. The results suggest that the inoculation of beneficial microbes plays a significant role in rescuing soybeans under heavy metal stress. They create a dynamic, complex interaction with plants via a cascade called plant-microbial interaction. It enhances stress metal tolerance via the production of phytohormones, gene expression, and secondary metabolites. Overall, microbial inoculation is essential in mediating plant protection responses to heavy metal stress produced by a fluctuating climate.

Plant growth promoting potential of urea doped calcium phosphate nanoparticles in finger millet (Eleusine coracana (L.) Gaertn.) under drought stress

Drought is a leading threat that impinges on plant growth and productivity. Nanotechnology is considered an adequate tool for resolving various environmental issues by offering avant-garde and pragmatic solutions. Using nutrients in the nano-scale including CaP-U NPs is a novel fertilization strategy for crops. The present study was conducted to develop and utilize environment-friendly urea nanoparticles (NPs) based nano-fertilizers as a crop nutrient. The high solubility of urea molecules was controlled by integrating them with a matrix of calcium phosphate nanoparticles (CaP NPs). CaP NPs contain high phosphorous and outstanding biocompatibility. Scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and X-ray diffraction analysis (XRD) were used to characterize the fabricated NPs. FE-SEM determined no areas of phase separation in urea and calcium phosphate, indicating the successful formation of an encapsulated nanocomposite between the two nano matrices. TEM examination confirmed a fiber-like structure of CaP-U NPs with 15 to 50 nm diameter and 100 to 200 nm length. The synthesized CaP-U NPs and bulk urea (0.0, 0.1% and 0.5%) were applied by foliar sprays at an interval of 15 days on pre-sowed VL-379 variety of finger millet (Eleusine coracana (L.) Gaertn.), under irrigated and drought conditions. The application of the CaP-U NPs significantly enhanced different plant growth attributes such as shoot length (29.4 & 41%), root length (46.4 & 51%), shoot fresh (33.6 & 55.8%) and dry weight (63 & 59.1%), and root fresh (57 & 61%) and dry weight (78 & 80.7%), improved pigment system (chlorophyll) and activated plant defense enzymes such as proline (35.4%), superoxide dismutase (47.7%), guaiacol peroxidase (30.2%), ascorbate peroxidase (70%) under both irrigated and drought conditions. Superimposition of five treatment combinations on drought suggested that CaP-U NPs at 0.5 followed by 0.1% provided the highest growth indices and defense-related enzymes, which were significantly different. Overall, our findings suggested that synthesized CaP-U NPs treatment of finger millet seeds improved plant growth and enzymatic regulation, particularly more in drought conditions providing insight into the strategy for not only finger millet but probably for other commercial cereals crops which suffer from fluctuating environmental conditions.

Modifications in Ultrastructural Characteristics and Redox Status of Plants under Environmental Stress: A Review

The rate of global environmental change is unprecedented, with climate change causing an increase in the oscillation and intensification of various abiotic stress factors that have negative impacts on crop production. This issue has become an alarming global concern, especially for countries already facing the threat of food insecurity. Abiotic stressors, such as drought, salinity, extreme temperatures, and metal (nanoparticle) toxicities, are recognized as major constraints in agriculture, and are closely associated with the crop yield penalty and losses in food supply. In order to combat abiotic stress, it is important to understand how plant organs adapt to changing conditions, as this can help produce more stress-resistant or stress-tolerant plants. The investigation of plant tissue ultrastructure and subcellular components can provide valuable insights into plant responses to abiotic stress-related stimuli. In particular, the columella cells (statocytes) of the root cap exhibit a unique architecture that is easily recognizable under a transmission electron microscope, making them a useful experimental model for ultrastructural observations. In combination with the assessment of plant oxidative/antioxidative status, both approaches can shed more light on the cellular and molecular mechanisms involved in plant adaptation to environmental cues. This review summarizes life-threatening factors of the changing environment that lead to stress-related damage to plants, with an emphasis on their subcellular components. Additionally, selected plant responses to such conditions in the context of their ability to adapt and survive in a challenging environment are also described.

Assessment of Black Rot in Oilseed Rape Grown under Climate Change Conditions Using Biochemical Methods and Computer Vision

Global warming is a challenge for plants and pathogens, involving profound changes in the physiology of both contenders to adapt to the new environmental conditions and to succeed in their interaction. Studies have been conducted on the behavior of oilseed rape plants and two races (1 and 4) of the bacterium Xanthomonas campestris pv. campestris (Xcc) and their interaction to anticipate our response in the possible future climate. Symptoms caused by both races of Xcc were very similar to each other under any climatic condition assayed, although the bacterial count from infected leaves differed for each race. Climate change caused an earlier onset of Xcc symptoms by at least 3 days, linked to oxidative stress and a change in pigment composition. Xcc infection aggravated the leaf senescence already induced by climate change. To identify Xcc-infected plants early under any climatic condition, four classifying algorithms were trained with parameters obtained from the images of green fluorescence, two vegetation indices and thermography recorded on Xcc-symptomless leaves. Classification accuracies were above 0.85 out of 1.0 in all cases, with k-nearest neighbor analysis and support vector machines performing best under the tested climatic conditions.

Chronic Ionizing Radiation of Plants: An Evolutionary Factor from Direct Damage to Non-Target Effects

In present times, the levels of ionizing radiation (IR) on the surface of Earth are relatively low, posing no high challenges for the survival of contemporary life forms. IR derives from natural sources and naturally occurring radioactive materials (NORM), the nuclear industry, medical applications, and as a result of radiation disasters or nuclear tests. In the current review, we discuss modern sources of radioactivity, its direct and indirect effects on different plant species, and the scope of the radiation protection of plants. We present an overview of the molecular mechanisms of radiation responses in plants, which leads to a tempting conjecture of the evolutionary role of IR as a limiting factor for land colonization and plant diversification rates. The hypothesis-driven analysis of available plant genomic data suggests an overall DNA repair gene families' depletion in land plants compared to ancestral groups, which overlaps with a decrease in levels of radiation exposure on the surface of Earth millions of years ago. The potential contribution of chronic IR as an evolutionary factor in combination with other environmental factors is discussed.

Transcriptomic hallmarks of in vitro TiO2 nanotubes toxicity in Chlamydomonas reinhardtii

Recently, more accessible transcriptomic approaches have provided a new and deeper understanding of environmental toxicity. The present study focuses on the transcriptomic profiles of green microalgae Chlamydomonas reinhardtii exposed to new industrially promising material, TiO₂ nanotubes (NTs), as an example of a widely used one-dimensional nanomaterial. The first algal in vitro assay included 2.5 and 7.5 mg/L TiO₂ NTs, resulting in a dose-dependent negative effect on biological endpoints. At a working concentration of 7.5 mg/L, RNA-sequencing showed a mainly negative effect on the cells. In summary, the results indicated metabolic disruption, ^{such as ATP loss, damage to mitochondria and chloroplasts, loss of solutes due to permeated membranes,} and cell wall damage. Moreover, apoptosis-induced transcripts were detected. Interestingly, reactivation of transposons was observed. In signalling and transcription pathways, including chromatin remodelling and locking, the annotated genes were downregulated.

Toxicity assessment of metribuzin and its amelioration through plant growth regulators in Vigna radiata (L.) R. Wilczek

The present experiment was conducted to evaluate the metribuzin-induced stress response in Vigna radiata and to explore the ameliorative role of exogenous application of plant growth regulators (PGRs) against metribuzin toxicity by assessing important biochemical and yield parameters. Prior to the field experiment, dose standardization experiments were performed, and EC₅₀ was calculated for metribuzin. On day 21, field grown V. radiata plants were treated with graded concentrations of metribuzin (0-1000 mg [Formula: see text]). Plants treated with 600 mg [Formula: see text] (EC₅₀) and 1000 mg [Formula: see text] (highest dose) of metribuzin were co-treated individually and simultaneously with gibberellic acid-3 (GA), indole-3 acetic acid (IAA), and salicylic acid (SA). After 7 days of treatment, leaf tissues were analyzed for biochemical parameters, whereas those related to yield were recorded during harvest. The result of this study indicated that metribuzin treatment to V. radiata resulted in increase in lipid peroxidation and reduce chlorophyll and carotenoid contents as well as yield parameters. However, metribuzin-treated plants induced proline accumulation and activity of antioxidant enzymes. Exogenous application of GA, IAA, and SA significantly reduced lipid peroxidation and increased contents of photosynthetic pigments, proline, and antioxidant enzymes thereby increasing yield parameters. It was observed that during metribuzin stress, SA exhibited a better ameliorative response out of the three exogenously applied PGRs, while the combined use of all PGRs exhibited much improved ameliorative response on biochemical and yield parameters of plants.

Effects of harpin and carbendazim on antioxidant accumulation in young jujube leaves

Jujube leaf tea is a functional beverage that soothes the nerves. In this study, we evaluated the effects of carbendazim and harpin on disease index, biomass accumulation, H2O2, antioxidant contents, and phenyl alanine ammonia lyase (PAL) activity in young jujube leaves. Compared to harpin, carbendazim decreased the disease index and induced higher H2O2 content. Additionally, the pesticide reduced young leaf biomass accumulation. In contrast, harpin increased vitamin C, glutathione, total phenolics, and total antioxidant capacity in young leaves compared to carbendazim. Compared with the control, harpin enhanced the PAL activity. Carbendazim residues were present in treated leaves for 14 days. Our study findings provide a method for improving jujube leaf tea quality from a pesticide utilization perspective.