Physiological and oxidative stress responses of Solanum lycopersicum (L.) (tomato) when exposed to different chemical pesticides

Chemical Desiccation in the Preharvest of Cowpea: A Study of How the Time of Application Interferes in the Enzymatic and Physiological Aspects of Seedlings from Desiccated Plants

Chemical desiccation in the preharvest of grains and seeds is commonly used in production fields. Using herbicides for this purpose is a viable alternative to reduce beans' exposure to adverse crop conditions. Our objectives were to evaluate (1) the efficacy of herbicides for accelerated defoliation of cowpea, (2) the impact of herbicide application on antioxidant enzyme activity and protein and amino acid contents in seeds, and (3) the effects of different herbicide application schedules on the physiological aspects of seeds. In the first experiment, in addition to the control treatment (without herbicides), seven herbicides and two mixtures were applied at night: diquat, flumioxazin, diquat + flumioxazin, glufosinate ammonium, saflufenacil, carfentrazone, diquat + carfentrazone, atrazine, and glyphosate. Diquat and its mixtures showed greater efficacy in anticipating the harvest. Flumioxazin and diquat alone reduced amino acid content by 61.72 and 51.44%, respectively. The same trend was observed for total soluble proteins. The activity of antioxidant enzymes (CAT, POD, PPO) increased, indicating oxidative stress caused by diquat and flumioxazin. In the second experiment, we tested three application times (6 a.m., 12 p.m., 6 p.m.) with diquat, diquat + flumioxazin, and diquat + carfentrazone. The lowest damage to chlorophyll a was at 6 a.m.; other times reduced photosynthetic pigments and increased carotenoid content. Total soluble sugars decreased by 27.74% with nocturnal application of diquat + flumioxazin. Our data indicate that herbicide use for desiccation affects seed quality. These findings highlight the need for selecting appropriate herbicides and application times. Future research should explore long-term impacts on crop yield and quality.

PGPR-Enabled bioremediation of pesticide and heavy metal-contaminated soil: A review of recent advances and emerging challenges

The excessive usage of agrochemicals, including pesticides, along with various reckless human actions, has ensued discriminating prevalence of pesticides and heavy metals (HMs) in crop plants and the environment. The enhanced exposure to these chemicals is a menace to living organisms. The pesticides may get bioaccumulated in the food chain, thereby leading to several deteriorative changes in the ecosystem health and a rise in the cases of some serious human ailments including cancer. Further, both HMs and pesticides cause some major metabolic disturbances in plants, which include oxidative burst, osmotic alterations and reduced levels of photosynthesis, leading to a decline in plant productivity. Moreover, the synergistic interaction between pesticides and HMs has a more serious impact on human and ecosystem health. Various attempts have been made to explore eco-friendly and environmentally sustainable methods of improving plant health under HMs and/or pesticide stress. Among these methods, the employment of PGPR can be a suitable and effective strategy for managing these contaminants and providing a long-term remedy. Although, the application of PGPR alone can alleviate HM-induced phytotoxicities; however, several recent reports advocate using PGPR with other micro- and macro-organisms, biochar, chelating agents, organic acids, plant growth regulators, etc., to further improve their stress ameliorative potential. Further, some PGPR are also capable of assisting in the degradation of pesticides or their sequestration, reducing their harmful effects on plants and the environment. This present review attempts to present the current status of our understanding of PGPR's potential in the remediation of pesticides and HMs-contaminated soil for the researchers working in the area.

A comprehensive analysis of royal jelly protection against cypermethrin-induced toxicity in the model organism Allium cepa L., employing spectral shift and molecular docking approaches

In this study, the toxicity of the pesticide cypermethrin and the protective properties of royal jelly against this toxicity were investigated using Allium cepa L., a model organism. Toxicity was evaluated using 6 mg/L cypermethrin, while royal jelly (250 mg/L and 500 mg/L) was used in combination with cypermethrin to test the protective effect. To comprehend toxicity and protective impact, growth, genotoxicity, biochemical, comet assay and anatomical parameters were employed. Royal jelly had no harmful effects when applied alone. On the other hand, following exposure to cypermethrin, there was a reduction in weight increase, root elongation, rooting percentage, mitotic index (MI), and chlorophyll a and b. Cypermethrin elevated the frequencies of micronucleus (MN) and chromosomal aberrations (CAs), levels of proline and malondialdehyde (MDA), and the activity rates of the enzymes catalase (CAT) and superoxide dismutase (SOD). A spectral change in the DNA spectrum indicated that the interaction of cypermethrin with DNA was one of the reasons for its genotoxicity, and molecular docking investigations suggested that tubulins, histones, and topoisomerases might also interact with this pesticide. Cypermethrin also triggered some critical meristematic cell damage in the root tissue. At the same time, DNA tail results obtained from the comet assay revealed that cypermethrin caused DNA fragmentation. When royal jelly was applied together with cypermethrin, all negatively affected parameters due to the toxicity of cypermethrin were substantially restored. However, even at the maximum studied dose of 500 mg/L of royal jelly, this restoration did not reach the levels of the control group. Thus, the toxicity of cypermethrin and the protective function of royal jelly against this toxicity in A. cepa, the model organism studied, were determined by using many different approaches. Royal jelly is a reliable, well-known and easily accessible protective functional food candidate against the harmful effects of hazardous substances such as pesticides.

Imidacloprid triggered changes in strawberry fruits on edible quality and phenolic profiles by applied at two growth stages

Increasing evidence showed that imidacloprid affects plants' abiotic or biotic stress tolerance. However, the effects of imidacloprid on the quality of fruits remain elusive. This work aimed to study the effects of imidacloprid applied at different growth stages on the edible quality and phenolic profile of strawberry fruit in the field experiment. For the first time, lower fruit quality was observed in the mature strawberry fruits after imidacloprid treatment at the fruit-bearing completion stage (five days after pollination). Compared to the control group, the mature strawberry fruit wights and the SCC/TA ratio declined about 18.2-30.0 % and 10.3-16.8 %, respectively. However, those attributes did not occur in the mature strawberry fruits by imidacloprid treatment at the fruit maturation stage (30 days after pollination). Among the 30 phenolic compounds, nine presented significant up-regulation or down-regulation after imidacloprid application at two different growth stages, suggesting that the application period played an essential role in evaluating the effects of imidacloprid on the quality of fruits. A significant effect on fruit quality was presented at the strawberry early growth stage treated by imidacloprid. This study provided a new insight into how and when imidacloprid affects the quality of strawberry fruits, contributing to the future's more scientific application of imidacloprid on strawberries.

Uptake, translocation, accumulation, and metabolism of fluroxypyr-meptyl and oxidative stress induction in rice seedling

Fluroxypyr-meptyl (FLUME) is heterocyclic herbicide with internal absorption and transmission characteristics. Owing to its low cost and rapid efficacy, it has been widely used to control broad-leaved weeds in wheat, corn, and rice fields. However, the uptake, translocation, accumulation, and metabolism of FLUME in rice seedlings and the extent of oxidative stress induced by it remain largely unknown, which consequently restricts the comprehensive risk assessment of FLUME residues in the environment during rice production. Hence, we systematically investigated the growth and physiological responses of rice to FLUME and analyzed its uptake, translocation, accumulation, and metabolism in rice seedlings. The results indicated that under 0-0.12 mg/L FLUME treatment, only a small proportion of FLUME was translocated upward and accumulated in rice shoots following absorption via roots, with all the translocation factor values being < 1. Moreover, the distribution and enrichment ability of FLUME in rice seedlings were greater in roots than in shoots. Furthermore, we revealed that FLUME accumulation in rice seedlings evidently inhibited their growth and activated the defense system against oxidative stress, with an increase in the activity of antioxidant and detoxifying enzymes. In addition, multiple metabolic reactions of FLUME were observed in rice seedlings, including dehalogenation, hydroxylation, glycosylation, acetylation, and malonylation. Our study provides systematic insights into the uptake, translocation, accumulation, and metabolism of FLUME in rice seedlings as well as the oxidative stress induced by FLUME accumulation, which can help improve FLUME applications and environmental risk assessments in crops.

Effects of Water Deficit on Growth and Productivity in Tomato Crops Irrigated with Water Treated with Very Low-Frequency Electromagnetic Resonance Fields

The tomato crop is very sensitive to stress conditions. A water deficit is defined as when precipitation is less than the evapotranspiration (ETc) of the crop in a given period, and in this scenario of climate change, it is identified as responsible for global productivity losses. The use of potential technologies for better irrigation management, such as electromagnetically treated water, remains controversial. Thus, the objective of the present work was to investigate the effects of very low-frequency electromagnetic resonance field treatment on water for tomato crops submitted to different irrigation rates. For this, an experiment was carried out under controlled conditions with different types of water: electromagnetically treated water (WTVLF) and untreated water (UNW), as well as four water replacement rates: 40, 60, 80, and 100% ETc. The electromagnetic treatment of the water was carried out using the commercial equipment AQUA4D®. The experiment was carried out in pots with five replications per treatment. Lower activity of SOD, POD, CAT, and APX enzymes was observed in plants irrigated with water treated with very low-frequency electromagnetic resonance fields (WTVLF), indicating less oxidative stress caused by water deficit. Water deficit reduced chlorophyll content, but the effects were less harmful with WTVLF water. The water deficit resulted in less accumulation of dry matter and less productivity in a linear relationship. However, plants irrigated with WTVLF showed increments of about 20% in dry matter accumulation and 20% in fruit production concerning plants irrigated with untreated water, independent of the irrigation rates. We can conclude that irrigation with WTVLF can be a solution to reduce the damage caused by water deficits and increase the productivity of tomato crops.

Assessing phytotoxicity and cyto-genotoxicity of two insecticides using a battery of in-vitro biological assays

Intensive use of chemical pesticides in agriculture poses environmental risks and may have negative impacts on agricultural productivity. The potential phytotoxicity of two chemical pesticides, chlorpyrifos (CPS) and fensulfothion (FSN), were evaluated using Cicer arietinum and Allium cepa as model crops. Different concentrations (0-100 μgmL-1) of both CPS and FSN decreased germination and biological attributes of C. arietinum. High pesticide doses significantly (p ≤ 0.05) caused membrane damage by producing thiobarbituric acid reactive substances (TBARS) and increasing proline (Pro) content. Pesticides elevated ROS levels and substantially increased the superoxide anions and H2O2 concentrations, thus aggravating cell injury. Plants exposed to high pesticide dosages displayed significantly higher antioxidant levels to combat pesticide-induced oxidative stress. Ascorbate peroxidase (APX), guaiacol peroxidase (GPX), catalase (CAT), peroxidase (POD), and superoxide dismutase (SOD) increased by 48%, 93%, 71%, 52% and 94%, respectively, in C. arietinum roots exposed to 100 µgFSNmL-1. Under CLSM, pesticide-exposed C. arietinum and 2',7'-dichlorodihydrofluorescein diacetate (2'7'-DCF) and 3,3'-diaminobenzidine stained roots exhibited increased ROS production in a concentration-dependent manner. Additionally, enhanced Rhodamine 123 (Rhd 123) and Evan's blue fluorescence in roots, as well as changes in mitochondrial membrane potential (ΔΨm) and cellular apoptosis, were both associated with high pesticide dose. Allium cepa chromosomal aberration (CAs) assay showed a clear reduction in mitotic index (MI) and numerous chromosomal anomalies in root meristematic cells. Additionally, a-dose-dependent increase in DNA damage in root meristematic cells of A. cepa and conversion of the super-coiled form of DNA to open circular in pBR322 plasmid revealed the genotoxic potential of pesticides. The application of CPS and FSN suggests phytotoxic and cyto-genotoxic effects that emphasize the importance of careful monitoring of current pesticide level in soil before application and addition at optimal levels to soil-plant system. It is appropriate to prepare both target-specific and slow-release agrochemical formulations for crop protection with concurrent safeguarding of agroecosystems.

Review on Pesticide Abiotic Stress over Crop Health and Intervention by Various Biostimulants

Plants are essential for life on earth, and agricultural crops are a primary food source for humans. For the One Health future, crop health is crucial for safe, high-quality agricultural products and the development of future green commodities. However, the overuse of pesticides in modern agriculture raises concerns about their adverse effects on crop resistance and product quality. Recently, biostimulants, including microecological bacteria agents and nanoparticles, have garnered worldwide interest for their ability to sustain plant health and enhance crop resistance. This review analyzed the effects and mechanisms of pesticide stress on crop health. It also investigated the regulation of biostimulants on crop health and the multiomics mechanism, combining research on nanoselenium activating various crop health aspects conducted by the authors' research group. The paper helps readers understand the impact of pesticides on crop health and the positive influence of various biostimulants, especially nanomaterials and small molecules, on crop health.

Dynamics of dominant rhizospheric microbial communities responsible for trichlorfon absorption and translocation in maize seedlings

In this study, the available phosphorus (AP) and TCF concentrations in soils and maize (Zea mays) seedling tissues were measured in response to escalating TCF concentrations during 216 hr of culture. Maize seedlings growth considerably enhanced soil TCF degradation, reaching the highest of 73.2% and 87.4% at 216 hr in 50 and 200 mg/kg TCF treatments, respectively, and increased AP contents in all the seedling tissues. Soil TCF was majorly accumulated in seedling roots, reaching maximum concentration of 0.017 and 0.076 mg/kg in TCF-50 and TCF-200, respectively. The hydrophilicity of TCF might hinder its translocation to the aboveground shoot and leaf. Using bacterial 16 S rRNA gene sequencing, we found that TCF addition drastically lessened bacterial community interactions and hindered the complexity of their biotic networks in rhizosphere than in bulk soils, leading to the homogeneity of bacterial communities that were resistant or prone to TCF biodegradation. Mantel test and redundancy analysis suggested a significant enrichment of dominant species Massilia belonging to Proteobacteria phyla, which in turn affecting TCF translocation and accumulation in maize seedling tissues. This study provided new insight into the biogeochemical fate of TCF in maize seedling and the responsible rhizobacterial community in soil TCF absorption and translocation.

Analysis of impacts of exogenous pollutant bisphenol-A penetration on soybeans roots and their biological growth

Bisphenol A (BPA) is a common chemical used in plastic production. BPA, which has the potential to be poisonous to plants, has lately emerged as a serious environmental concern owing to its extensive usage and release patterns. Prior study has only looked at how BPA affects plants up to a certain stage in their growth. The precise mechanism of toxicity, penetration of BPA, and damage to internal root tissues remains unknown. Therefore, the goal of this study was to examine the hypothesized mechanism for BPA-induced root cells by studying the effects of bisphenol A (BPA) on the ultrastructure and function of root tip cells of soybean plants. We looked at plant changes in root cell tissues after BPA exposure. Further, the biological characteristics that responded to BPA stress were investigated, and the accumulation of BPA in the root, stem, and leaf of the soybean plant was systematically investigated by using FTIR and SEM analysis. The uptake of BPA is a key internal factor that contributes to changes in biological characteristics. Our findings provide insight into how BPA could alter plant root growth, which might contribute new knowledge toward a better scientific appraisal of the possible dangers of BPA exposure for plants.

Genomics, Proteomics, and Metabolomics Approaches to Improve Abiotic Stress Tolerance in Tomato Plant

To explore changes in proteins and metabolites under stress circumstances, genomics, proteomics, and metabolomics methods are used. In-depth research over the previous ten years has gradually revealed the fundamental processes of plants' responses to environmental stress. Abiotic stresses, which include temperature extremes, water scarcity, and metal toxicity brought on by human activity and urbanization, are a major cause for concern, since they can result in unsustainable warming trends and drastically lower crop yields. Furthermore, there is an emerging reliance on agrochemicals. Stress is responsible for physiological transformations such as the formation of reactive oxygen, stomatal opening and closure, cytosolic calcium ion concentrations, metabolite profiles and their dynamic changes, expression of stress-responsive genes, activation of potassium channels, etc. Research regarding abiotic stresses is lacking because defense feedbacks to abiotic factors necessitate regulating the changes that activate multiple genes and pathways that are not properly explored. It is clear from the involvement of these genes that plant stress response and adaptation are complicated processes. Targeting the multigenicity of plant abiotic stress responses caused by genomic sequences, transcripts, protein organization and interactions, stress-specific and cellular transcriptome collections, and mutant screens can be the first step in an integrative approach. Therefore, in this review, we focused on the genomes, proteomics, and metabolomics of tomatoes under abiotic stress.

Degradable Self-Destructive Redox-Responsive System Based on Mesoporous Organosilica Nano-Vehicles for Smart Delivery of Fungicide

The development of stimuli-responsive controlled release formulations is a potential method of improving pesticide utilization efficiency and alleviating current pesticide-related environmental pollution. In this study, a self-destruction redox-responsive pesticide delivery system using biodegradable disulfide-bond-bridged mesoporous organosilica (DMON) nanoparticles as the porous carriers and coordination complexes of gallic acid (GA) and Fe(III) ions as the capping agents were established for controlling prochloraz (PRO) release. The GA-Fe(III) complexes deposited onto the surface of DMON nanoparticles could effectively improve the light stability of prochloraz. Due to the decomposition of GA-Fe(III) complexes, the nano-vehicles had excellent redox-responsive performance under the reducing environments generated by the fungus. The spreadability of PRO@DMON-GA-Fe(III) nanoparticles on the rice leaves was increased due to the hydrogen bonds between GA and rice leaves. Compared with prochloraz emulsifiable concentrate, PRO@DMON-GA-Fe(III) nanoparticles showed better fungicidal activity against Magnaporthe oryzae with a longer duration under the same concentration of prochloraz. More importantly, DMON-GA-Fe(III) nanocarriers did not observe obvious toxicity to the growth of rice seedlings. Considering non-toxic organic solvents and excellent antifungal activity, redox-responsive pesticide controlled release systems with self-destruction properties have great application prospects in the field of plant disease management.

Alleviation of Herbicide Toxicity in Solanum lycopersicum L.-An Antioxidant Stimulation Approach

Application of the herbicide glyphosate in crops is a common practice among farmers around the world. Tomato is one of the crops that are treated with glyphosate to fight weed growth and loss of crop. However, tomato plants often show phytotoxic effects from glyphosate. In this study, the ability of pongamia oil derived from Pongamia pinnata (known also as Millettia pinnata) tree to alleviate the herbicide glyphosate toxicity effects in tomato (S.lycopersicum L. cv. Micro-tom) plants was tested. Tomato plants were treated with a mixture of a dose of (GLY) glyphosate (10 mg kg−1) and different doses of pongamia oil (PO) foliar spray (5, 10, 50, and 100 mM) and compared with the herbicide or oil control (glyphosate 10 mg kg−1 or pongamia oil PO 50 mM). Some morphological features, non-enzymatic and enzymatic antioxidants, and gene expression were observed. Glyphosate-treated plants sprayed with PO 50 mM (GLY + PO 50) showed increased root biomass (0.28 g-p ≤ 0.001), shoot biomass (1.2 g-p ≤ 0.01), H2O2 (68 nmol/g), and the activities of superoxide dismutase (SOD; 40 mg-p ≤ 0.001), catalase (CAT; 81.21 mg-p ≤ 0.05), ascorbate peroxidase (APX; 80 mg-p ≤ 0.01) and glutathione reductase (GR; 53 min/mg-F4,20 = 15.88, p ≤ 0.05). In contrast, these plants showed reduced contents of Malondialdehyde (MDA; 30 nmol/g-F4,20 = 18.55, p ≤ 0.01), O2 (0.6 Abs/g), Prolne (Pro; 345 µg/g), Glutathine (GSH; 341 nmol/mg-p ≤ 0.001), ascorbate (AsA; 1.8 µmol/gm), ascorbic acid (AA; 1.62 mg-p ≤ 0.05) and dehydroascorbate (DHAR; 0.32 mg p ≤ 0.05). The gene expression analysis was conducted for seven oxidative stress related genes besides the house-keeping gene Actin as a reference. The gene CYP1A1450 showed the highest mRNA expression level (6.8 fold ± 0.4) in GLY-treated tomato plants, whereas GLY-treated plants + PO 50 showed 2.9 fold. The study concluded that foliar spray of 50 mM pongamia oil alleviated the toxic effects of glyphosate on tomato plants in the form of increased root and shoot biomass, SOD, CAT, APX, and GR activity, while reduced MDA, O2, Pro, GSH, AsA, AA, DHAR, and gene CYP1A1450 expression.

Microorganisms in Plant Growth and Development: Roles in Abiotic Stress Tolerance and Secondary Metabolites Secretion

Crops aimed at feeding an exponentially growing population are often exposed to a variety of harsh environmental factors. Although plants have evolved ways of adjusting their metabolism and some have also been engineered to tolerate stressful environments, there is still a shortage of food supply. An alternative approach is to explore the possibility of using rhizosphere microorganisms in the mitigation of abiotic stress and hopefully improve food production. Several studies have shown that rhizobacteria and mycorrhizae organisms can help improve stress tolerance by enhancing plant growth; stimulating the production of phytohormones, siderophores, and solubilizing phosphates; lowering ethylene levels; and upregulating the expression of dehydration response and antioxidant genes. This article shows the secretion of secondary metabolites as an additional mechanism employed by microorganisms against abiotic stress. The understanding of these mechanisms will help improve the efficacy of plant-growth-promoting microorganisms.