文心兰原球茎形态发生与可溶性物质及抗氧化酶的关系

以文心兰切花品种'南茜'无菌苗为材料,取其茎尖通过组织培养诱导形成原球茎和幼苗,观察并分析了原球茎各形态发生阶段的特征及其可溶性糖和蛋白质含量、抗氧化酶(POD、CAT和SOD)活性以及相关同功酶(POD、EST和SOD)的变化.结果显示:(1)文心兰原球茎形态发生可分为外植体期、外植体膨大期、愈伤组织期、原球茎形成期、原球茎成熟期、叶鞘伸展期、顶端腋芽发育期及幼苗期8个阶段.(2)可溶性糖和蛋白质含量均在叶鞘伸展期出现最大峰值;POD活性在外植体膨大期、CAT和SOD活性在愈伤组织期分别出现最大峰值.SOD同工酶的2条酶带在愈伤组织期到幼苗期交替出现;EST同工酶在原球茎形成期有2条特异酶带.研究表明,可溶性糖和蛋白质的含量以及POD、CAT、SOD活性的特异变化与文心兰茎尖脱分化及原球茎再分化的实现密切相关,不同类型的同工酶在原球茎同一发生阶段表现出较大差异,EST同工酶的2条特异酶带可作为原球茎形成的标志.     

Defense response of resistant and susceptible genotypes of castor (Ricinus communis L.) to wilt disease

The biochemical basis of resistance in castor (Ricinus communis L.) to Fusarium wilt, caused by the pathogen Fusarium oxysporum f. sp. ricini, was investigated. Induction of plant defence against pathogen attack is regulated by a complex network of different signals. Thus changes in various biochemical defenses including antioxidant enzymes, phenolic compounds and pathogenesis related (PR) proteins were investigated in the roots of resistant and susceptible genotypes of castor at 0, 24, 48 and 72 h.a.i. Infection by F. oxysporum significantly increased the superoxide dismutase (SOD) and peroxidase (POX) activities in the roots of susceptible genotypes, while the catalase (CAT) activities were appreciably higher in the roots of resistant genotypes at different stages. Constitutive levels of ascorbate peroxidase (APX) and polyphenol oxidase (PPO) were higher in the resistant genotypes. Also, the activities of phenylalanine ammonia lyase (PAL) and β 1, 3 glucanase significantly increased in the roots of the resistant genotypes after infections. The rate of increment of thiobarbituric acid reactive substances (TBARS) was higher in resistant genotypes after infection. Analysis of isozyme banding pattern of SOD, POX, PPO and esterase on native PAGE electrophoresis revealed that interaction between plant and fungi invoked various isozymes at 48 h of infection. SOD 3 was observed only in resistant genotypes at 24 h.a.i. except Geeta. Similarly induction of POX 5 was observed only in resistant genotypes at 48 h of infection, though the intensity of POX 5 was very less.     

Effects of salicylic acid and cold treatments on protein levels and on the activities of antioxidant enzymes in the apoplast of winter wheat leaves

The effects of salicylic acid (SA) and cold on apoplastic protein levels and activities of apoplastic catalase (CAT), peroxidase (POX) and polyphenol oxidase (PPO) were investigated in winter wheat (Triticum aestivum cv. Dogu-88) leaves. The plants were grown with and without 10 microM SA treatment at both control (20/18 degrees C for 30 and 45-day) and cold (10/5 degrees C for 30-day and 5/3 degrees C for 45-day) acclimatisations. Molecular masses of the apoplastic polypeptides were shown ranging in size from 20 to 66 kDa on SDS-PAGE. Accumulation and pattern of the polypeptides were changed by both SA and cold. It is observed that CAT, POX and PPO activities at 45-day control leaves were higher than at 30-day. When the activities with SA and cold treatments are compared to their controls, CAT activities were decreased while POX and PPO activities were increased by both the treatments. When the activities with cold+SA treatment are compared to their cold treatments, CAT and POX activities were decreased while PPO activity was increased by SA. It is concluded that exogenous SA can be involved in cold tolerance by regulating apoplastic proteins and antioxidant enzyme activities.     

Activities of antioxidant system components and polyphenol oxidase in ontogeny of lawn grasses under megapolis conditions

The activities of antioxidants enzymes (peroxidase (POX) and catalase (CAT)), the contents of non-enzymatic antioxidants (vitamin C, carotenoids), and the activity of polyphenol oxidase (PPO) were studied in vegetative organs of red clover (Trifolium pratense L.) and meadow-fescue (Festuca pratensis Huds.) growing under city conditions. The plants of three ages (virginal (V), generative (G), and subsenyl (SS)) were analyzed. The highest POX and PPO activities were characteristic of G plants, whereas CAT was most active in V plants. The content of low-molecular-weight antioxidants depended on species specificity and developmental stage and also on environment pollution. The content of ascorbate (vitamin C) declined linearly with plant development. Medium pollution also reduced the ascorbate content in tested plant leaves and roots. In contrast, the content of carotenoids increased with the increased activity of anthropogenic factors. The highest content of the pigments was in G plants. At all developmental stages and in all habitats, meadow-fescue (tolerant species) was characterized by the lower content of studied compounds than red clover (sensitive species). Thus, anthropogenic medium pollution resulted in the peroxide group accumulation, POX and PPO activation, carotenoid accumulation, and the ascorbate content decline in the vegetative tissues during the entire ontogeny of tolerant and sensitive lawn plants.     

Antioxidative defense system in pigeonpea roots under waterlogging stress

Pigeonpea [Cajanus cajan (L.) Millsp.] is a waterlogging-sensitive legume crop. We studied the effect of waterlogging stress on hydrogen peroxide (H₂O₂) content, lipid peroxidation and antioxidant enzyme activities in two pigeonpea genotypes viz., ICPL-84023 (waterlogging resistant) and MAL-18 (waterlogging susceptible). In a pot experiment, waterlogging stress was imposed for 6 days at early vegetative stage (20 days after sowing). Waterlogging treatment significantly increased hydrogen peroxide accumulation and lipid peroxidation, which indicated the extent of oxidative injury posed by stress conditions. Enzyme activities of peroxidase (POX), catalase (CAT), ascorbate peroxidase (APX), superoxide dismutase (SOD) and polyphenol oxidase (PPO) increased in pigeonpea roots as a consequence of waterlogged conditions, and all the enzyme activities were significantly higher in waterlogged ICPL-84023 than in MAL-18. POX activity was the maximum immediately after imposing stress, therefore, it was suggested to be involved in early scavenging of H₂O₂, while rest of the enzymes (CAT, APX, SOD and PPO) were more important in late responses to waterlogging. Present study revealed that H₂O₂ content is directly related to lipid peroxidation leading to oxidative damage during waterlogging in pigeonpea. Higher antioxidant potential in ICPL-84023 as evidenced by enhanced POX, CAT, APX, SOD and PPO activities increased capacity for reactive oxygen species (ROS) scavenging and indicated relationship between waterlogging resistance and antioxidant defense system in pigeonpea.     

Olive (Olea europaea L.) freezing tolerance related to antioxidant enzymes activity during cold acclimation and non acclimation

The changes in the antioxidant enzymes activity, total protein and proline content and their correlations with freezing tolerance (FT) (expressed as LT₅₀) were investigated at 11 different olive cultivars at cold-acclimation (CA, in February) and non-acclimation (NA, in August) stages. Leaf samples were collected from each cultivar and were divided into two groups. The first group was immediately frozen in liquid nitrogen for further biochemical analysis. The second ones was subjected to different freezing temperatures (?5, ?10, ?15 and ?20 °C) for 10 h, in order to determine their FT. The unfrozen control samples were kept at 4 °C. The results showed that Fishomi, Mission and Shengeh were the most freezing tolerant among other cultivars. In contrast, Zard, Manzanilla and Amigdalolia were the most sensitive ones. The cold acclimation enhanced the activities of superoxide dismutase (SOD), peroxidase (POD), ascorbate peroxidase (APX), catalase (CAT), polyphenol oxidase (PPO) and total protein content. However, proline content and phenylalanine ammonia-lyase (PAL) activity did not change or even decreased slightly at CA stage, compare to those samples at NA stage. It was found that LT₅₀ to be closely correlated to POD, CAT, and PPO activity at CA and NA stages. Overall, higher leaf POD, CAT, and PPO activity could be used as important selection criteria in screening tolerant olive cultivars for cold zone climatic.     

Investigation of in vitro and in vivo antioxidant potential of secoisolariciresinol diglucoside

The present study was designed to evaluate the in vitro and in vivo ameliorative antioxidant potential of secoisolariciresinol diglucoside (SDG). In vitro antioxidant activity of synthetic SDG was carried out using DPPH, reducing power potency, and DNA protection assays. Wistar albino rats weighing 180–220 g were used for in vivo studies and liver damage was induced in the experimental animals by a single intraperitoneal (I.P.) injection of CCl₄ (2 g/kg b.w.). Intoxicated animals were treated orally with synthetic SDG at (12.5 and 25 mg/kg b.w.) and Silymarin (25 mg/kg) for 14 consecutive days. The levels of catalase (CAT), superoxide dismutase (SOD), peroxidase (POX), and lipid peroxidase (LPO) were measured in liver and kidney homogenates. The synthetic SDG exerts high in vitro antioxidant potency as it could scavenge DPPH at a IC₅₀ value of 78.9 μg/ml and has dose-dependent reducing power potency and protected DNA at 0.5 mg/ml concentration. Oral administration of synthetic SDG at 12.5 and 25 mg/kg b.w. showed significant protection compared to Silymarin (25 mg/kg) and the activities of CAT, SOD, and POX were markedly increased (P < 0.05), whereas LPO significantly decreased (P < 0.001) in a dose-dependent manner in liver and kidney in both pre- and post-treatment groups when compared to toxin-treated group. The results of in vitro and in vivo investigations revealed that synthetic SDG at 25 mg/kg b.w. is associated with beneficial changes in hepatic enzyme activities and thereby plays a key role in the prevention of oxidative damage in immunologic system.     

添加外源锌对大杯香菇子实体细胞保护酶活性的影响

摘要：【目的】本实验研究了添加外源锌（Zn）对大杯香菇子实体保护酶活性的影响。【方法】以硫酸锌为外源锌,添加到培养料中,制成0、10、20、30、40、50 mg/kg 6个浓度。采用分光光度法测定大杯香菇子实体超氧化物岐化酶（SOD）活性、过氧化物酶（POD）活性、多酚氧化酶（PPO）活性、丙二醛（MDA）含量和可溶性蛋白含量,采用高锰酸钾滴定法过氧化氢酶（CAT）活性。【结果】添加外源 Zn浓度为30 mg/kg处理大杯香菇子实体内可溶性蛋白含量、SOD、POD和CAT活性极显著提高（P＜0.01）,PPO活性极显著减少（P＜0.01）,而MDA含量显著下降（P＜0.05）。随着Zn水平进一步升高,可溶性蛋白含量、SOD、POD和CAT活性呈下降趋势,而MDA含量极显著和显著上升（P＜0.01和P＜0.05）。【结论】高用量的Zn浓度能使大杯香菇子实体中的MDA含量上升,SOD、POD、CAT活性均下降,对保护酶系统有破坏作用,促进自由基的积累,从而导致膜脂过氧化作用的加剧。适宜Zn浓度能提高保护酶的活性,从而抑制了大杯香菇子实体中细胞膜脂过氧化水平,减轻膜伤害。     

Antioxidant enzyme activities, malondialdehyde, and total phenolic content of PEG-induced hyperhydric leaves in sugar beet tissue culture

Hyperhydricity is a physiological abnormality that frequently affects shoots that are vegetatively propagated in vitro. In this study, sugar beet (Beta vulgaris L. cv. Felicita) shoot tip explants were cultured on Murashige and Skoog medium supplemented with different concentrations of polyethylene glycol (PEG) 6000. We observed that higher concentrations of PEG 6000 and longer exposure (up to 4 wk) resulted in increasing levels of hyperhydration as well as browning and/or blackening of tissues in culture. A comparison of hyperhydric shoots with controls on the 28th day showed a marked increase in the content of water, phenolics, and malondialdehyde (MDA), which was positively correlated with an increase in the accumulation of PEG 6000. Selected antioxidant enzyme activities, including superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), guaiacol peroxidase (POX), and polyphenol oxidase (PPO) also increased in hyperhydric shoots, especially at lower concentrations of PEG 6000. Regression analysis indicated that strong linear relationships exist between SOD–APX (R ²?=?0.932), SOD–CAT (R ²?=?0.753), SOD–total phenolic content (R ²?=?0.966), APX–PPO (R ²?=?0.842), APX–total phenolic content (R ²?=?0.904), POX–CAT (R ²?=?0.751), and CAT–total phenolic content (R ²?=?0.806). Despite the correlation between different antioxidant enzymes and between the antioxidant enzymes and antioxidant compounds, was not able to prevent ROS damage in hyperhydric shoots. The negative correlation between SOD–MDA, POX–MDA, CAT–MDA, and MDA–total phenolics also indicated an increase in antioxidant enzyme activities, yet the increase in these antioxidant compound contents did not prevent lipid peroxidation of in vitro propagated beet shoots.     

Changes in activities of antioxidant enzymes and their gene expression during leaf development of sweetpotato

To understand the functions of antioxidant enzymes during leaf development in sweetpotato, we investigated the activities of several antioxidant enzymes such as superoxide dismutase (SOD), peroxidase (POX), ascorbate peroxidase (APX) and catalase (CAT). Significant increases were observed in the activities of SOD, POX and APX during the late stage of leaf development, whereas CAT activity increased during the early developmental stage. By RT-PCR analysis, various POX and APX genes showed differential expression patterns during leaf development. Four POX genes swpa3, swpa4, swpa6, swpb4 and one APX gene swAPX1 exhibited high levels of gene expression during the senescence stage of leaf development, but two POX genes, swpa1 and swpa7 were preferentially expressed at both the mature green and the late senescence stages of leaf development. These results indicate that hydrogen peroxide (H₂O₂)-related antioxidant enzymes are differentially regulated in the process of leaf development of sweetpotato.     

Alterations in photosynthetic pigments,protein, and carbohydrate metabolism in a wild plant <Emphasis Type="Italic">Coronopus didymus</Emphasis> L. (Brassicaceae) under lead stress

Coronopus didymus has been emerged as a promising wild, unpalatable plant species to alleviate lead (Pb) from the contaminated soils. This work investigated the hypothesis regarding various metabolic adaptations of C. didymus under lead (Pb) stress. In pot experiments, we assessed the effect of Pb at varied concentrations (500–2900 mg kg^?1) on growth, photosynthetic pigments, alteration of macromolecular (protein and carbohydrate) content, and activities of enzymes like protease, α-and β-amylase, peroxidase (POX), and polyphenol oxidase (PPO) in C. didymus for 6 weeks. Results revealed that Pb exposure enhanced the growth, protein, and carbohydrate level, but decreased the leaf pigment concentration and activities of hydrolytic enzymes. The activities of POX and PPO in roots increased progressively by ~337 and 675%, respectively, over the control, at 2900 mg kg^?1 Pb treatment. Likewise, contemporaneous findings were noticed in shoots of C. didymus, strongly indicating its inherent potential to cope Pb-induced stress. Furthermore, the altered plant biochemical status and upregulated metabolic activities of POX and PPO indulged in polyphenol peroxidation elucidate their role in allocating protection and conferring resistance against Pb instigated stress. The current work suggests that stress induced by Pb in C. didymus stimulated the POX and PPO activities which impart a decisive role in detoxification of peaked Pb levels, perhaps, by forming physical barrier or lignifications.     

He-Ne激光处理不同时期蚕豆幼苗对抗氧化系统的影响

采用功率为3.50 mW/mm2的He-Ne激光处理不同时期蚕豆,研究其四叶期叶片中丙二醛(MDA)含量,超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性及同工酶谱的变化。结果表明,与对照相比,He-Ne激光处理不同时期蚕豆,MDA含量均显著降低,且各处理间没有显著差异;SOD、POD、CAT酶活性有不同程度提高。SOD、POD同工酶的酶谱在浸种24小时和胚芽露头期经激光处理后改变,在一叶期处理后没有改变;CAT同工酶谱没有变化;在一叶期处理的三种同工酶谱都没有改变。     

Effects of Iso-osmotic Concentrations of NaCl and Mannitol on some Metabolic Activity in Calluses of Two Salicornia species

The comparative effects of salinity and drought on activity of antioxidant enzymes such as superoxide dismutase (SOD), peroxidase (POX), catalase (CAT), and polyphenol oxidase (PPO) and contents of protein, proline, hydrogen peroxide, malondialdehyde (MDA), and carotenoids were studied in calluses of Salicornia persica and Salicornia europaea. Calluses were cultured on Murashige and Skoog medium (MS medium) containing iso-osmotic concentrations of NaCl (100, 300, and 600 mM) and mannitol (200, 500, and 1000 mM). Proline content increased in calluses of both species under NaCl- and mannitol-induced stresses. Under both stresses, S. persica accumulated higher amounts of protein as compared to S. europaea. Under both stresses, protein content in S. persica decreased in comparison to control. Antioxidant enzyme activities showed different trends in the two Salicornia species under salt and drought stresses but were higher in S. europaea than in S. persica. Changes of hydrogen peroxide and MDA contents of calluses subjected to salt stress followed a pattern different from that observed under drought stress. MDA content showed similar changes to hydrogen peroxide content. Carotenoid content decreased in both species under both stresses. Overall, at the cellular level, S. europaea calluses were more tolerant to both NaCl- and mannitol-induced stresses than calluses of S. persica.     

Salt Stress Induced Changes in Growth and Enzyme Activities in Germinating Phaseolus Mungo Seeds

NaCl salt stress induced changes in growth and enzyme activities in blackgram (Phaseolus mungo L.) seeds during germination were studied. A decrease in germination percentage, root length, shoot length, and fresh mass was noticed with an increase in NaCl concentration. With the increase in NaCl concentration and duration of stress proline content increased and catalase (CAT), peroxidase (POX) and polyphenol oxidase (PPO) activities decreased.     

Influence of salinity and <Emphasis Type="Italic">Fusarium oxysporum</Emphasis> as the stress factors on morpho-physiological and yield attributes in onion

Occurrence of salt stress with the soil borne fungus Fusarium oxysporum f. sp. cepa (FOC) are potential threat to the crop yield. This investigation reports effect of the concurrent stresses (salinity and FOC) on morpho-physiological and yield attributes in onion. In vitro growth tests revealed proliferation of FOC biomass at different levels of salinity (2–8 dS m^?1). A greenhouse pot experiment with the proposed levels of salinity (2.5, 3.5 and 4.5 dS m^?1) in combination with FOC inoculation showed more drastic effect of combined stress on disease severity, plant growth and bulb as compared to the individual stress. In general, osmotic potential, total chlorophyll content, membrane stability index and total protein content of the leaf were decreased, while total phenolics were increased due to the given stress/s. Total sugar content decreased due to effect of the  individual stress of FOC, while it increased under the individual stress of salinity and in combination with FOC. FOC infection did not change activity of polyphenol oxidase (PPO), while it improved peroxidase (POX) and phenylalanine ammonia lyase (PAL) and decreased catalase (CAT) activity. Activities of POX and PPO increased, however PAL and CAT declined under individual as well as simultaneous stress of salinity ?and ?FOC. The research work concluded that FOC will be a more severe disease threat for onion cultivation in saline soils.     

Activity of antioxidant enzyme during <Emphasis Type="Italic">in vitro</Emphasis> organogenesis in <Emphasis Type="Italic">Crocus sativus</Emphasis>

The effect of various hormonal combinations on regeneration of shoots and roots from meristem-derived callus of Crocus sativus L. and activities of antioxidant enzymes have been studied. The most efficient regeneration occurred with 1.0 mg dm⁻³ 1-naphthaleneacetic acid (NAA) + 1.0 mg dm⁻³ thidiazuron and 1.0 mg dm⁻³ NAA + 2.0 mg dm⁻³ kinetin. For sprouting, regenerated shoot were subcultured on Murashige and Skoog medium containing 1.0 mg dm⁻³ NAA + 1.0 mg dm⁻³ benzylaminopurine (BAP). Protein content and superoxide dismutase activity decreased in regenerated shoots and roots and increased in sprouting shoots, while catalase (CAT), peroxidase (POX) and polyphenol oxidase (PPO) activities increased during organogenesis and decreased in sprouting shoots. High CAT and PPO activities were detected in regenerated roots, whereas high POX activity was observed in regenerated shoot.     

Effect of drought on biomass, protein content, lipid peroxidation and antioxidant enzymes in two sesame cultivars

The effects of drought on growth, protein content, lipid peroxidation, superoxide dismutase (SOD), peroxidase (POX), catalase (CAT) and polyphenol oxidase (PPO) were studied in leaves and roots of Sesamum indicum L. cvs. Darab 14 and Yekta. Four weeks after sowing, plants were grown under soil moisture corresponding to 100, 75, 50 and 25 % field capacity for next four weeks. Fresh and dry masses, and total protein content in leaves and roots decreased obviously under drought. However, several new proteins appeared and content of some proteins was affected. Measurement of malondialdehyde content in leaves and roots showed that lipid peroxidation was lower in Yekta than in Darab 14. Severe stress increased SOD, POX, CAT and PPO activities in leaves and roots, especially in Yekta. According to the present study Yekta is more resistant to drought than Darab 14.     

Effects of heat stress on development,reproduction and activities of protective enzymes in Mononychellus mcgregori

Mononychellus mcgregori is a pest mite of cassava. Since its invasion into China in 2008 it has spread rapidly. In order to determine the potential distribution and to analyze its invasion, diffusion and ecological adaptation mechanisms, we investigated the effect of high-temperature stress (30, 33, 36, 39 and 42 °C) on its development and reproduction, and the activity of protective enzymes in the mite. The results indicated significant influences: (1) adults could not lay eggs after they had been exposed to 42 °C for 4 h or longer; (2) egg development was slower and egg hatchability decreased after exposure of adults to 33–42 °C for 1 h; (3) offspring development (all stages) was slower after exposure of adults to 33–42 °C for 2 h or more; and (4) polyphenol oxidase (PPO), peroxidase (POD), ascorbate peroxidase (APX) and catalase (CAT) activities in the adults increased to high levels after exposure to 33–42 °C for 1 h, and superoxide dismutase activity increased only after exposure to 42 °C for 1 h. In conclusion, exposure to high temperatures for only 1 h probably has an important impact on the mite’s population growth. The significant increase of PPO, POD, APX, and CAT activities in adults may partially explain how M. mcgregori survive exposure to a relatively high temperature.     

Changes in antioxidant activities and phenol content in tomato plants subjected to partial root drying and regulated deficit irrigation

Abstract

Partial rootzone drying (PRD) and regulated deficit irrigation (RDI) are water saving irrigation systems that have been developed to increase water use efficiency (WUE) without significant yield reduction. To examine whether tomato responded differently to RDI and PRD, we compared the changes in antioxidative defenses in tomato plants using a split-root system. Tomato plants were grown for 21 days under controlled conditions with their roots separated equally between two soil compartments. Three irrigation treatments were imposed: Control, receiving an amount of water equivalent to 100% of plant transpiration; PRD in which one compartment was watered with 50% of the amount of water supplied to the controls, allowing one-half of the root system to be exposed to dry soil, and switching irrigation between sides weekly; RDI in which 50% of the amount of water given to the controls was supplied, half to each side of the root system. Relative water content (RWC), midday leaf Ψ and chlorophyll content decreased largely in RDI-treated plants, whereas the PRD plants exhibited relatively higher Ψ and RWC values. An enhanced level of lipid peroxidation in both roots and leaves indicated that PRD and RDI caused oxidative stress in tomato plants. In leaves, superoxide dismutase (SOD), soluble peroxidase (POX) and polyphenol oxidase (PPO) activities showed an increase in the early phase of water deficit, and then decreased in the remaining phase of the drying cycle. However, the increase was more pronounced under RDI. Catalase (CAT) activity declined continuously from the onset of PRD and RDI treatments to below the control level, and the reduction was less under PRD than RDI. POX cell-wall associated activities exceeded the control level by 450% and 230%, respectively, under RDI and PRD. At the root level, while CAT activity also decreased under both PRD and RDI, the activities of SOD, POX and PPO significantly increased and their activities showed an alternating increase/decrease paralleling the alternating irrigation in PRD-treated roots. As a result of the difference in POX and PPO activities between the two water treatments applied, PRD-treated plants accumulated more soluble and cell-wall bound phenolic compounds.     

Biochemical alterations in leaves of resistant and susceptible cotton genotypes infected systemically by cotton leaf curl Burewala virus

Leaf curl disease caused by Cotton Leaf Curl Burewala virus (CLCuBuV) has been recognized as serious threat to cotton in Indian subcontinent. However, information about cotton–CLCuBuV interaction is still limited. In this study, the level of phenolic compounds, total soluble proteins, and malondialdehyde (MDA) and the activities of phenylalanine ammonia-lyase (PAL), peroxidase (POX), catalase (CAT), proteases, superoxide dismutase (SOD), and polyphenol oxidase (PPO) were studied in leaves of two susceptible (CIM-496 & NIAB-111) and two resistant (Ravi and Co Tiep Khac) cotton genotypes. Disease symptoms were mild in the resistant genotypes but were severe in highly susceptible genotypes. The results showed that phenolic compounds, proteins, PAL, POX, CAT, proteases, SOD, PPO, and MDA play an active role in disease resistance against CLCuBuV. The amount of total phenols, proteases, MDA, and PPO was significantly higher in leaves of CLCuBuV-inoculated plants of both resistant genotypes as in non-inoculated plants, and decreased in CLCuBuV-inoculated plants of both susceptible genotypes over their healthy plants. POX, protein content, SOD, and PAL activities showed lower values in resistant genotypes, while they decreased significantly in susceptible genotypes as compared to the noninoculated plants except PAL, which showed non-significant decrease. CAT was found to be increased in both susceptible and resistant genotypes with maximum percent increase in resistant genotype Ravi, as compared to non-inoculated plants. The results showed significantly higher concentrations of total phenols and higher activity of protease, MDA, SOD, and PPO in resistant genotype Ravi after infection with CLCuBuV, suggesting that there is a correlation between constitutive induced levels of these enzymes and plant resistance that could be considered as biochemical markers for studying plant-virus compatible and incompatible interactions.