Exogenous hesperidin and chlorogenic acid alleviate oxidative damage induced by arsenic toxicity in Zea mays through regulating the water status, antioxidant capacity, redox balance and fatty acid composition

Arsenic-induced plant stress: Mitigation strategies and omics approaches to alleviate toxicity

Arsenic (As) is a metalloid pollutant that is extensively distributed in the biosphere. As is among the most prevalent and toxic elements in the environment; it induces adverse effects even at low concentrations. Due to its toxic nature and bioavailability, the presence of As in soil and water has prompted numerous agricultural, environmental, and health concerns. As accumulation is detrimental to plant growth, development, and productivity. Toxicity of As to plants is a function of As speciation, plant species, and soil properties. As inhibits root proliferation and reduces leaf number. It is associated with defoliation, reduced biomass, nutrient uptake, and photosynthesis, chlorophyll degradation, generation of reactive oxygen species, membrane damage, electrolyte leakage, lipid peroxidation and genotoxicity. Plants respond to As stress by upregulating genes involved in detoxification. Different species have adopted avoidance and tolerance responses for As detoxification. Plants also activate phytohormonal signaling to mitigate the stressful impacts of As. This review addresses As speciation, uptake, and accumulation by plants. It describes plant morpho-physiological, biochemical, and molecular changes and how phytohormones respond to As stress. The review closes with a discussion of omic approaches for alleviating As toxicity in plants.

Pervasive influence of heavy metals on metabolic pathways is potentially relieved by hesperidin to enhance the phytoremediation efficiency of Bassia scoparia

Hesperidin (HSP), a flavonoid, is a potent antioxidant, metal chelator, mediator of signaling pathways, and regulator of metal uptake in plants. The study examined the ameliorative effects of HSP (100 μM) on Bassia scoparia grown under excessive levels of heavy metals (zinc (500 mg kg-1), copper (400 mg kg-1), cadmium (100 mg kg-1), and chromium (100 mg kg-1)). The study clarifies the underlying mechanisms by which HSP lessens metabolic mayhem to enhance metal stress tolerance and phytoremediation efficiency of Bassia scoparia. Plants manifested diminished growth because of a drop in chlorophyll content and nutrient acquisition, along with exacerbated deterioration of cellular membranes reflected in elevated reactive oxygen species (ROS) production, lipid peroxidation, and relative membrane permeability. Besides the colossal production of cytotoxic methylglyoxal, the activity of lipoxygenase was also higher in plants under metal toxicity. Conversely, hesperidin suppressed the production of cytotoxic ROS and methylglyoxal. Hesperidin improved oxidative defense that protected membrane integrity. Hesperidin caused a more significant accumulation of osmolytes, non-protein thiols, and phytochelatins, thereby rendering metal ions non-toxic. Hydrogen sulfide and nitric oxide endogenous levels were intricately maintained higher in plants treated with HSP. Hesperidin increased metal accumulation in Bassia scoparia and thereby had the potential to promote the reclamation of metal-contaminated soils.

Hesperidin and chlorogenic acid mitigate arsenic-induced oxidative stress via redox regulation, photosystems-related gene expression, and antioxidant efficiency in the chloroplasts of Zea mays

The ubiquitous metalloid arsenic (As), which is not essential, can be found extensively in the soil and subterranean water of numerous nations, raising substantial apprehensions due to its impact on both agricultural productivity and sustainability. Plants exposed to As often display morphological, physiological, and growth-related abnormalities, collectively leading to reduced productivity. Polyphenols, operating as secondary messengers within the intricate signaling networks of plants, assume integral functions in the acquisition of resistance to diverse environmental stressors, including but not limited to drought, salinity, and exposure to heavy metals. The pivotal roles played by polyphenols in these adaptive processes underscore their profound significance in plant biology. This study aims to elucidate the impact of hesperidin (HP) and chlorogenic acid (CA), recognized as potent bioactive compounds, on maize plants exposed to As. To achieve this objective, the study examined the physiological and biochemical impacts, including growth parameters, photosynthesis, and chloroplastic antioxidants, of HP (100 μM) and CA (50 μM) on Zea mays plants exposed to arsenate stress (AsV, 100 μM - Na2HAsO4⋅7H2O). As toxicity led to reductions in fresh weight (FW) and dry weight (DW) by 33% and 26%, respectively. However, the application of As+HP and As + CA increased FW by 22% and 40% and DW by 14% and 17%, respectively, alleviating the effects of As stress. As toxicity resulted in the up-regulation of PSII genes (psbA and psbD) and PSI genes (psaA and psaB), indicating a potential response to the re-formation of degraded regions, likely driven by the heightened demand for photosynthesis. Exogenous HP or/and CA treatments effectively counteracted the adverse effects of As toxicity on the photochemical quantum efficiency of PSII (Fv/Fm). H2O2 content showed a 23% increase under As stress, and this increase was evident in guard cells when examining confocal microscopy images. In the presence of As toxicity, the chloroplastic antioxidant capacity can exhibit varying trends, with either a decrease or increase observed. After the application of CA and/or HP, a significant increase was observed in the activity of GR, APX, GST, and GPX enzymes, resulting in decreased levels of H2O2 and MDA. Additionally, the enhanced functions of MDHAR and DHAR have modulated the redox status of ascorbic acid (AsA) and glutathione (GSH). The HP or CA-mediated elevated levels of AsA and GSH content further contributed to the preservation of redox homeostasis in chloroplasts facing stress induced by As. In summary, the inclusion of HP and CA in the growth medium sustained plant performance in the presence of As toxicity by regulating physiological and biochemical characteristics, chloroplastic antioxidant enzymes, the AsA-GSH cycle and photosynthesis processes, thereby demonstrating their significant potential to confer resistance to maize through the mitigation of As-induced oxidative damage and the safeguarding of photosynthetic mechanisms.

Effect of hesperidin on growth, photosynthesis, antioxidant systems and uptake of cadmium, copper, chromium and zinc by Celosia argentea plants

Rapid industrialization and extensive agricultural practices are the major causes of soil heavy metal contamination, which needs urgent attention to safeguard the soils from contamination. However, the phytotoxic effects of excessive metals in plants are the primary obstacle to efficient phytoextraction. The present study evaluated the effects of hesperidin (HSP) on metals (Cu, Cd, Cr, Zn) phytoextraction by hyperaccumulator (Celosia argentea L.) plants. For this purpose, HSP, a flavonoid compound with strong antioxidant potential to assist metal phytoextraction was used under metal stress in plants. Celosia argentea plants suffered significant (P ≤ 0.001) oxidative damage due to the colossal accumulation of metals (Cu, Cd, Cr, Zn). However, HSP supplementation notably (P ≤ 0.001) abated ROS generation (O2•‒, •OH, H2O2), lipoxygenase activity, methylglyoxal production, and relative membrane permeability that clearly indicated HSP-mediated decline in oxidative injury in plants. Exogenous HSP improved (P ≤ 0.001) the production of non-protein thiol, phytochelatins, osmolytes, and antioxidant compounds. Further, HSP enhanced (P ≤ 0.001) H2S and NO endogenous production, which might have improved the GSH: GSSG ratio. Consequently, HSP-treated C. argentea plants had higher biomass alongside elevated metal accumulation mirrored as profound modifications in translocation factor (TF), bioaccumulation coefficient (BAC), and bioconcentration factor (BCF). In this context, HSP significantly enhanced TF of Cr (P ≤ 0.001), Cd (P ≤ 0.001), and Zn (P ≤ 0.01), while BAC of Cr (P ≤ 0.001), Cd (P ≤ 0.001), and Zn (P ≤ 0.001). Further, BCF was significant (P ≤ 0.05) only in plants grown under Cr-spiked soil. Overall, HSP has the potential for phytoremediation of metals by C. argentea, which might be a suitable strategy for metal-polluted soils.

Interactive effects of selenium and arsenic on phenolic constituents and antioxidant activity in rice (Oryza sativa L.)

Arsenic (As) is a heavy toxic metalloid found in air, water and soil that adversely affects the plant growth by inducing oxidative stress in plants. Its contamination of rice is a serious problem throughout the world. Selenium (Se) is a beneficial micronutrient for plants that acts as an antioxidant at low doses and protect the plants against number of environmental stresses either by modulating the primary metabolic pathways or regulating the production of phenolic compounds. In the present investigation, effect of Se on different phenolics, enzymes related to their metabolism and antioxidative potential were studied in As stressed rice leaves. Rice plants were grown in pots containing sodium arsenate (2-10 mg As(V) kg-1 soil) and sodium selenate (0.5-1 mg Se kg-1 soil), both alone and in combination and leaf samples were analyzed for various biochemical parameters. Phenolic constituents increased in rice leaves with As(V) treatment from 2 to 5 mg kg-1 soil and leaves exposed to As(V) @ 5 mg kg-1 soil exhibited 1.7, 1.9 and 2.5 fold increase in total phenolics, o-dihydroxyphenols and flavonols, respectively at grain filling stage. Binary application of Se + As improved various phenolic constituents, FRAP, reducing power and antioxidant activities as compared to control. PAL, TAL and PPO activities increased from 1.3 to 4.6 fold in combined As + Se treatment at both the stages. Anthocyanin contents showed a decline (10.8 fold) with increasing As doses and its content improved at both the stages with maximum increase of 3.76 fold with As5+Se1 combination. Binary application of As + Se improved gallic acid, chlorogenic acid, 3-hydroxy benzoic acid and kaempferol contents than control whereas catechin and coumaric acid showed the reverse trend. Application of Se can modulate phenolic constituents in leaf and grains of rice Cv PR126 due to As stress that helped plants to adapt to excess As and resulted in improved plant growth.

Toxicity of co-exposure of microplastics and lead in African catfish (Clarias gariepinus)

Microplastics (MPs) are an emerging threat to freshwater ecosystems with several ecotoxicological ramifications for fish. Microplastics (MPs) can adsorb heavy metals on their surfaces and increase their availability to aquatic organisms. The combined impact of lead and microplastics on fish has only been studied seldom utilizing a variety of markers. The present study aimed to evaluate the hematological, biochemical, and inflammatory signals (cytokines), as well as antioxidant enzymes in African catfish (Clarias gariepinus) exposed to lead (Pb) and MPs individually and combined for 15 days (acute toxicity experiment). The fish were split into four groups, the first of which was the control group. The second group received exposure to 1 mg/L of lead nitrate [Pb(NO3)2]. The third group was given 100 mg/L of MPs. A solution containing 100 mg/L of MPs and 1 mg/L of lead nitrate [Pb(NO3)2] was administered to the fourth group (the combination group). According to the findings, when MPs and Pb were combined for 15 days, the red blood cells (RBCs), thrombocytes, and lymphocytes were significantly reduced in comparison to the control fish. When compared to the control fish, the fish exposed to MPs and Pb alone or together showed a significant rise in blood interleukin-1β (IL-1β) and interleukin-6 (IL-6) cytokines. Both MPs and Pb exposure in catfish resulted in significant changes in the plasma electrolytes. The fish treated with MPs and Pb individually or in combination showed significant reduction in superoxide dismutase (SOD) and total antioxidant capacity (TAC) levels compared to the control group. The fish exposed to the combined action of MPs and Pb showed a considerable modification in all biochemical markers. The difference in the mean concentration of Pb (mg/L) between the fish exposed to Pb alone and the fish subjected to Pb and MPs combination was not statistically significant. In conclusion, according to this investigation, exposure to Pb caused an insignificant increase in Pb accumulation when MPs were present. However, co-exposure may result in anemia, cellular harm, extremely high levels of oxidative stress, and an inflammatory reaction.

Hormones and the antioxidant transduction pathway and gene expression, mediated by Serratia marcescens DB1, lessen the lethality of heavy metals (As, Ni, and Cr) in Oryza sativa L

Microorganisms have recently gained recognition as efficient biological tool for reducing heavy metal toxicity in crops. In this experiment, we isolated a potent heavy metal (As, Ni, and Cr) resistant rhizobacterium Serratia marcescens DB1 and detected its plant growth promoting traits such as phosphate solubilization, gibberellin synthesis, organic acid production and amino acid regulation. Based on these findings, DB1 was further investigated for application in a rice var. Hwayeongbyeo subjected to 1 mM As, 4 mM Ni, and 4 mM Cr stress. The rice plants treated with Cr and Ni appeared healthy but were lethal, indicating unfitness for consumption due to toxic metal deposition, whereas the plants treated with > 1 mM As instantaneously died. Our results showed that DB1 inoculation significantly decreased metal accumulation in the rice shoots. Particularly, Cr uptake dropped by 16.55% and 22.12% in (Cr + DB1) and (Cr + As + Ni + DB1), respectively, As dropped by 48.90% and 35.82% in (As + DB1) and (Cr + As + Ni + DB1), respectively, and Ni dropped by 7.95% and 19.56% in (Ni + DB1) and (Cr + As + Ni + DB1), respectively. These findings were further validated by gene expression analysis results, which showed that DB1 inoculation significantly decreased the expression of OsPCS1 (a phytochelatin synthase gene), OsMTP1 (a metal transporting gene), and OsMTP5 (a gene for the expulsion of excess metal). Moreover, DB1 inoculation considerably enhanced the morphological growth of rice through modulation of endogenous phytohormones (abscisic acid, salicylic acid, and jasmonic acid) and uptake of essential elements such as K and P. These findings indicate that DB1 is an effective biofertilizer that can mitigate heavy metal toxicity in rice crops.

Biological Activities of p-Hydroxycinnamic Acids in Maintaining Gut Barrier Integrity and Function

It is well established that p-Hydroxycinnamic acids (HCAs), including ferulic, caffeic, sinapic, and p-coumaric acids, possess a characteristic phenylpropanoid C6-C3 backbone and account for about one-third of the phenolic compounds in our diet. HCAs are typically associated with various plant cell wall components, including mono-, di-, and polysaccharides, sterols, polyamines, glycoproteins, and lignins. Interestingly, enzymes produced by intestinal microbes liberate HCAs from these associations. HCAs are completely absorbed in their free form upon ingestion and undergo specific reactions upon absorption in the small intestine or liver. The gut epithelium, composed of intestinal epithelial cells (IECs), acts as a physical barrier against harmful bacteria and a site for regulated interactions between bacteria and the gut lumen. Thus, maintaining the integrity of the epithelial barrier is essential for establishing a physiochemical environment conducive to homeostasis. This review summarizes the protective effects of HCAs on the intestinal barrier, achieved through four mechanisms: preserving tight junction proteins (TJPs), modulating pro-inflammatory cytokines, exerting antioxidant activity, and regulating the intestinal microbiota.

Protective role of quercetin and kaempferol against oxidative damage and photosynthesis inhibition in wheat chloroplasts under arsenic stress

Arsenic (As) toxicity negatively impacts plant development, limits agricultural production, and, by entering the food chain, endangers human health. Studies on the use of natural and bioactive molecules in increasing plants' resistance to abiotic stressors, such as As, have gained increasing attention in the last few years. Flavonols are plant secondary metabolites with high potential in stress tolerance due to their roles in signal transmission. Therefore, the focus of this study was to examine the effects of two flavonols, quercetin (Q, 25 μM) and kaempferol (K, 25 μM), on growth parameters, photosynthesis, and chloroplastic antioxidant activity in wheat leaves under As stress (100 μM). As stress reduced the relative growth rate by 50% and relative water content by 25% in leaves. However, applying Q and/or K alleviated the As-induced suppression of growth and water relations. Exogenous phenolic treatments reversed the effects of As toxicity in photochemistry and maintained the photochemical quantum efficiency of the Photosystem II (Fv /Fm ). As exposure increased, the H2 O2 content in wheat chloroplasts by 42% and high levels of H2 O2 accumulation were also observed in guard cells in confocal microscopy images. Analysis of the chloroplastic antioxidant system has shown that Q and K applications increase the activity of antioxidant enzymes, including superoxide dismutase, peroxidase, and ascorbate peroxidase. Phenolic applications have induced the ascorbate-glutathione (AsA-GSH) cycle in charge of the protection of the cellular redox balance in different ways. It has been determined that Q triggers the AsA renewal, and K maintains the GSH pool. As a result, Q and K applications provide tolerance to wheat plants under As stress by increasing the chloroplastic antioxidant system activity and protecting photosynthetic reactions from oxidative damage. This study reveals the potential use of plant phenolic compounds in agricultural systems as a biosafe strategy to enhance plant stress tolerance, hence increasing yield.

The protective impact of hesperidin against carbimazole-induced hypothyroidism, via enhancement of inflammatory cytokines, histopathological alterations, and Nrf2/HO-1

The aim of this study was to evaluate the anti-inflammatory, antioxidant, and antiproliferative effects of hesperidin (HSP) and eltroxin (ELT) on hypothyroidism (HPO) induced by carbimazole (CBZ) in white male albino rats. Thirty-two adult rats were categorized into four groups: Group 1, no treatment (control); Group II, treated with CBZ (20 mg/kg); Group III, treated with HSP (200 mg/kg) + CBZ; and Group IV, treated with ELT (0.045 mg/kg) + CBZ. All treatments were provided as oral daily doses for 90 days. Thyroid hypofunction was significantly manifested in Group II. However, increased levels of thyroid hormones, antioxidant enzymes, nuclear factor erythroid 2-related factor 2, heme oxygenase 1, and interleukin (IL)-10, and a decrease in the level of the thyroid-stimulating hormone were observed in Groups III and IV. On the contrary, decreased levels of lipid peroxidation, inducible nitric oxide synthase, tumor necrosis factor α, IL-17, and cyclooxygenase 2 were detected in groups III and IV. The histopathological and ultrastructural findings were ameliorated in Groups III and IV; on the contrary, Group II presented with significant increases in the height and number of layers of the follicular cells. Immunohistochemistry demonstrated a marked increase in thyroglobulin and significant decreases in the levels of nuclear factor kappa B and proliferating cell nuclear antigen in Groups III and IV. These results confirmed the effectiveness of HSP as an anti-inflammatory, antioxidant, and antiproliferative agent in rats with hypothyroidism. Additional studies are required to assess its potential as a novel agent against HPO.

Preparation and in vitro evaluation of hesperidin nanoparticles by antisolvent recrystallization in a double homogenate system

Hesperidin nanoparticles (HNPs) were made for the first time employing an antisolvent recrystallization technique in a double homogenate system with positive and negative clockwise rotation in order to completely use the underutilized nutritional components in citrus peel. Dimethyl sulfoxide (DMSO), ethanol, and deionized water were used as the solvents and antisolvents in the hesperidin solution preparation. Hesperidin solution concentration of 60.26 mg/mL, homogenization speed of 8257 rpm, antisolvent-to-solvent volume ratio of 6.93 mL/mL, and homogenization time of 3.15 min were the ideal experimental conditions. HNPs have to be at least 72.24 nm in size. The structures of the produced hesperidin samples and the raw hesperidin powder were identical, according to the findings of the FTIR, XRD, and TG characterization tests. The HNP sample had an in vitro absorption rate that was 5.63 and 4.23 times greater than that of the raw hesperidin powder, respectively. It was discovered that DMSO was more suited than ethanol for creating HNP particles. In the realms of dietary supplements, therapeutic applications, and health promotion, the HNPs produced by the ARDH technology would be a potential formulation on increasing uses for a wider range of nutraceuticals (synergistic).

Protective effects of hesperidin in cyclophosphamide-induced parotid toxicity in rats

Cyclophosphamide (CYP) is an alkylating agent that is used on a wide range as a treatment of malignancies and autoimmune diseases. Previous studies have shown the promising role of hesperidin (HSP) as an antioxidant agent against various models of toxic agents. The protective effect of the HSP against CYP-induced parotid damage was evaluated in this study. Forty rats (180-200 g) were divided into four equal groups: Group I (received normal saline), Group II (HSP-treated at a dose of 100 mg/kg/day for 7 consecutive days), Group III (CYP-treated at a dose of 200 mg/kg single intraperitoneal injection on the 7th day of the experiment), Group IV (CYP + HSP); HSP-treated at a dose of 100 mg/kg/day for 7 consecutive days and CYP (200 mg/kg) single intraperitoneal injection on the 7th day of the experiment. Afterwards, the oxidative stress and inflammatory markers, the histopathological and immunohistochemical alterations of the parotid tissues in the studied groups were evaluated. CYP intoxication induced a significant parotid tissue injury represented by the elevation in the values of malondialdehyde (MDA), tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) and decrease in the catalase activity and glutathione peroxidase (GPx). Histologically, extensive histopathological alterations e.g., widely spaced serous acini with irregular shapes and congested blood vessels as well as downregulated ki-67 and alpha-smooth muscle actin (α-SMA) immunoexpression were induced by CYP. HSP administration markedly improved the biochemical and the histopathological studies. We can conclude that HSP elicited protective effects against the CYP-induced parotid toxicity.

Mechanism of macroalgae Gracilaria bailiniae responding to cadmium and lanthanum

Macroalgae can accumulate a wide array of metals, leading to their appliance as biomonitors of aquatic environments. With the rapid development of industrial and agricultural-based activities, Cd pollution in aquatic environments is considered an increasingly severe problem worldwide. Although La could alleviate the Cd stress in higher terrestrial plants, the response mechanisms of macroalgae to Cd and La are unknown. Along these lines, in this work, Cd significantly affected the growth, internal cellular structure, photosynthesis, pigment content, antioxidant enzyme activity, and lipid peroxidation level of G. bailiniae. However, the presence of La alleviated these adverse effects from Cd. Furthermore, the response mechanism of G. bailiniae to Cd was attributed to the self-antioxidant ability enhancement, membrane defense, and programmed-cellular regulation. However, the presence of La mediated the biosynthesis of both flavonoids and lipids, which inhibited the Cd accumulation, modulated algal stress signalling networks, renewed the impaired chlorophyll molecule, maintained the activity of the crucial enzyme, enhanced antioxidant ability, and maintained the stabilization of redox homeostasis, alleviating the adverse impact from Cd and improve the growth of G. bailiniae. The experimental results successfully demonstrate a new detoxicant to alleviate Cd stress, promoting a more comprehensive array of macroalgal applications.

Combined effect of Bacillus siamensis and chlorogenic acid on maintenance of quality, control of disease in stored wax apple fruit

Objectives

The purpose of this study was to evaluate the effect of combined postharvest use of Bacillus siamensis strain and chlorogenic acid on quality mainteance and disease control in wax apple fruit.

Materials and Methods

Wax apple fruit were treated with Bacillus siamensis strain (N1), chlorogenic acid (CHA) and N1+CHA and preserved at 25℃for 12 days. The appearance and quality parameters were evaluated, along with the disease index (DI), content of total soluble solids (TSS), total acid (TA), vitamin C (Vc), total phenolic, and flavonoids during cold storage. Meanwhile, the activities of β-1,3-glucanase (GLU) , phenylalanine ammonialyase (PAL), polyphenol oxidase (PPO), and peroxidase (POD) were determined. Furthermore, the transcriptome and the expression level of key defense enzyme genes were analyzed by RNA-seq and real-time quantitative reverse transcription PCR (qRT-PCR).

Results

N1+CHA treatment significantly lowered DI and delayed fruit quality deterioration by slowing TSS and TA loss and enhancing antioxidant capacity, including Vc, total phenolic, and flavonoids content. Meanwhile, the activities of GLU, PAL, PPO and POD were dramatically increased by N1+CHA treatment. Additionally, N1+CHA treatment modulated several metabolic pathways, including those involved in plant-hormone signal transduction and plant-pathogen interaction. The expression level of key defense enzyme genes were significantly up-regulated in stored wax apple fruit by the N1+CHA treatment, which were well coincided with the transcriptome data.

Conclusion

The combined use of N1+CHA significantly prevent disease and maintain fruit quality of wax apple during storage. These findings indicate that it could serve as a promising biological technique for preserving wax apple fruit.

Arsenic-Induced Oxidative Stress and Antioxidant Defense in Plants

The non-essential metalloid arsenic (As) is widely distributed in soil and underground water of many countries. Arsenic contamination is a concern because it creates threat to food security in terms of crop productivity and food safety. Plants exposed to As show morpho-physiological, growth and developmental disorder which altogether result in loss of productivity. At physiological level, As-induced altered biochemistry in chloroplast, mitochondria, peroxisome, endoplasmic reticulum, cell wall, plasma membrane causes reactive oxygen species (ROS) overgeneration which damage cell through disintegrating the structure of lipids, proteins, and DNA. Therefore, plants tolerance to ROS-induced oxidative stress is a vital strategy for enhancing As tolerance in plants. Plants having enhanced antioxidant defense system show greater tolerance to As toxicity. Depending upon plant diversity (As hyperaccumulator/non-hyperaccumulator or As tolerant/susceptible) the mechanisms of As accumulation, absorption or toxicity response may differ. There can be various crop management practices such as exogenous application of nutrients, hormones, antioxidants, osmolytes, signaling molecules, different chelating agents, microbial inoculants, organic amendments etc. can be effective against As toxicity in plants. There is information gap in understanding the mechanism of As-induced response (damage or tolerance response) in plants. This review presents the mechanism of As uptake and accumulation in plants, physiological responses under As stress, As-induced ROS generation and antioxidant defense system response, various approaches for enhancing As tolerance in plants from the available literatures which will make understanding the to date knowledge, knowledge gap and future guideline to be worked out for the development of As tolerant plant cultivars.