Superoxide-Dismutase Deficient Mutants in Common Beans (Phaseolus vulgaris L.): Genetic Control, Differential Expressions of Isozymes, and Sensitivity to Arsenic
28 Aug 2013-BioMed Research International (Hindawi Publishing Corporation)-Vol. 2013, pp 782450-782450
TL;DR: Gene expressions using qRT PCR confirmed higher expressions of Cu/Zn SOD transcripts in both mutants and the absence of Fe SOD in sodPv 1 and Mn S OD in SodPv 2 and ROS-imaging study revealed overaccumulation of both superoxides and H2O2 in leaves of double mutant.
Abstract: Two common bean (Phaseolus vulgaris L.) mutants, sodPv 1 and sodPv 2, exhibiting foliar superoxide dismutase (SOD) activity of only 25% and 40% of their mother control (MC) cv. VL 63 were isolated in EMS-mutagenized (0.15%, 8 h) M2 progeny. Native-PAGE analysis revealed occurrence of Mn SOD, Fe SOD, Cu/Zn SOD I and Cu/Zn SOD II isozymes in MC, while Fe SOD, and Mn SOD were not formed in sodPv 1 and sodPv 2 leaves, respectively. In-gel activity of individual isozymes differed significantly among the parents. SOD deficiency is inherited as recessive mutations, controlled by two different nonallelic loci. Gene expressions using qRT PCR confirmed higher expressions of Cu/Zn SOD transcripts in both mutants and the absence of Fe SOD in sodPv 1 and Mn SOD in sodPv 2. In 50 μM arsenic, Cu/Zn SODs genes were further upregulated but other isoforms downregulated in the two mutants, maintaining SOD activity in its control level. In an F2 double mutants of sodPv 1 × sodPv 2, no Fe SOD, and Mn SOD expressions were detectable, while both Cu/Zn SODs are down-regulated and arsenic-induced leaf necrosis appeared. In contrast to both mutants, ROS-imaging study revealed overaccumulation of both superoxides and H2O2 in leaves of double mutant.
Citations
More filters
01 Jan 2016
TL;DR: The redox-dependent modification of sensitive signalling proteins is proposed as a key mode of redox signal transmission, which plays a key role in the adaptive response to the adverse environment.
Abstract: Plants are frequently exposed to different stressful factors, both of biotic or abiotic nature, which limit their growth and productivity. To survive under stress conditions, plants must activate stress-specific signalling pathways, which finally lead to morphological, physiological, and biochemical changes that allow to adapt to the adverse environment. Cellular redox homeostasis, determined by a complex interplay between pathways that produce and scavenge reactive oxygen species (ROS), plays a key role in the adaptive response. Each deviation in the cellular redox state, due to an imbalance of ROS production and/or scavenging, is indicative of environmental disturbance and works as a signal. Under stress conditions, different ROS are produced in many cell compartments. Plants have very proficient, versatile and flexible antioxidant machinery, which comprises enzymes and metabolites with distinct biochemical properties and distinct sub-cellular localization. The antioxidant systems play a key role in the control of redox homeostasis, determining either the extent or the specificity of ROS signals and the downstream redox-dependent responses. Redox signalling is responsive to a number of environmental cues, and the complex and dynamic pathways of redox regulation occur in different cell compartments. The redox-dependent modification of sensitive signalling proteins is proposed as a key mode of redox signal transmission. Each redox-dependent interaction is opportunely regulated by a restricted environment, whose change transfers the complex system of information and influences the plant response to external changes.
57 citations
TL;DR: Results indicated coordinated response of thiol-metabolism and antioxidant defense in conferring As-tolerance in lentil, and GSH is the key point in this cascade.
Abstract: Response of sulfate transporters, thiol metabolism, and antioxidant defense system was studied in roots of two lentil (Lens culinaris Medik.) genotypes grown in arsenic (10, 25, and 40 μM As(V))-supplemented nutrient solution, and significant changes compared to control (0 μM As(V)) were observed mainly at 25 and 40 μM. In L 414, high glutathione (GSH) redox (0.8-0.9) was maintained with elevated thiol synthesis, powered by transcriptional up-regulation of LcSultr1;1 and LcSultr1;2 sulfate transporters and significant induction of LcSAT1;1 and LcSAT1;2 (serine acetyltransferase), OAS-TL (O-acetylserine(thiol)-lyase), γ-ECS (γ-glutamylcysteine synthetase), and PCS (phytochelatin synthase) genes predominantly within 12-24 h of As exposure at 25 μM and within 6-12 h at 40 μM. This thiolic potency in L 414 roots was effectively complemented by up-regulation of gene expressions and consequent enhanced activities of superoxide dismutase, ascorbate peroxidase (APX), dehydroascorbate reductase, glutathione reductase (GR), and glutathione-S-transferase (GST) isoforms at 25 and 40 μMAs, efficiently scavenging excess reactive oxygen species to prevent onset of As-induced oxidative stress and consequent inhibition of root growth in L 414. In contrast, down-regulation of vital sulfate-uptake transporters as well as entire thiol-metabolizing system and considerably low APX, GST, and GR expressions in DPL 59 not only resulted in reduced GSH redox but also led to over-accumulation of H2O2. This triggered membrane lipid peroxidations as the marks of As-induced oxidative damage. Results indicated coordinated response of thiol-metabolism and antioxidant defense in conferring As-tolerance in lentil, and GSH is the key point in this cascade.
28 citations
TL;DR: In this article, the role of the superoxide dismutase (SOD), catalase (CAT), peroxidase (POX), and APX enzymes in Salvinia molesta tolerance to AsIII was investigated.
Abstract: Antioxidant enzymes are important components in the defense against arsenic (As) stress in plants. Here, we tested the hypothesis that Salvinia molesta, an aquatic fern, counteracts the harmful arsenite (AsIII) effects by activating scavenging reactive oxygen species (ROS) enzymes. Thus, our objective was to investigate the role of the superoxide dismutase (SOD), catalase (CAT), peroxidase (POX), and ascorbate peroxidase (APX) in S. molesta tolerance to AsIII and indicate the use of this plant in remediation of contaminated water. Plants were grown in nutrient solution at pH 6.5 and exposed to 0, 5, 10, or 20 µM AsIII for 96 h (analyses of As absorption, mineral nutrient content, and relative growth rate) and for 24 h (analyses of oxidative stress indicators and enzymatic antioxidant defenses). In the floating leaves, there was a greater basal activity of the antioxidant enzymes and less accumulation of As than in submerged leaves. The submerged leaves, which function as roots in S. molesta, accumulated more As than floating leaves, and SOD and CAT activities were inhibited. Thus, there was a greater production of ROS and oxidative stress. Our results show that S. molesta presents enzymatic antioxidant defenses to alleviate AsIII toxicity and are more effectives in the floating leaves. These results are important to elucidate the AsIII tolerance mechanisms in S. molesta and the possibility of their use in contamined water phytoremediation. Additional studies exposing plants to more prolonged stress and using AsIII concentrations closer to those found in contaminated environments will confirm this claim.
21 citations
Cites background from "Superoxide-Dismutase Deficient Muta..."
...Oxidative stress is the main deleterious AsIII effect in plants (Talukdar 2013; Singh et al. 2015a; Farooq et al. 2015), although it may also inhibit the catalytic function of enzymes by binding to their sulfhydryl groups, leading to metabolic damage (Sharma 2012; Farooq et al. 2016a)....
[...]
...The ROS increase can cause intense oxidative damage and promote plant tissue necrosis, affecting plant biomass (Talukdar and Talukdar 2013; Upadhyaya et al. 2014)....
[...]
TL;DR: Native PAGE analysis revealed that enzyme isoforms were involved in the regulation of foliar H2O2 metabolism, the level of which was found extremely critical in determining arsenic tolerance of grass pea genotypes.
Abstract: Response of four improved grass pea (Lathyrus sativus L.) genotypes to arsenic was tested in pot experiment using 30 mg As l−1 up to 60 days of growth after commencement of treatment (DAC). Arsenic exposure significantly reduced growth and seed yield potential of vars B1 and BioL-212, but no such effect was observed in bold-seeded mutant and pod indehiscent mutant lines. Results revealed normal leaf photosynthesis and antioxidant metabolism at 20 DAC in both varieties. However, high superoxide dismutase activity coupled with low ascorbate redox and declining ascorbate peroxidase level led to abnormal rise in H2O2 content at reproductive stages (40 and 60 DAC), consequently, resulting in significantly enhanced arsenic-induced oxidative damage and physiological impediment in both varieties. By contrast, H2O2 level in both the mutants was remarkably modulated at reproductive stage (40 DAC) in a highly controlled manner by balanced action of antioxidant defense. This favored normal photosynthesis and ensured good grain yield even under prolonged arsenic exposure by effectively preventing oxidative damage to membrane in both the mutants. Native PAGE analysis revealed that enzyme isoforms were involved in the regulation of foliar H2O2 metabolism, the level of which was found extremely critical in determining arsenic tolerance of grass pea genotypes.
12 citations
28 May 2016
TL;DR: Results suggested exogenous TU stimulated the Gly and antioxidant defense in fine tune against As-induced oxidative damage in lentil genotypes, as was evident from ROS-imaging study.
Abstract: Arsenic (As) is a wide-spread toxic and carcinogenic metalloid, affecting crop productivity worldwide. Lentil, an edible grain legume, is increasingly exposed to soil arsenic contamination. However, our understandings regarding mechanistic details and mitigation strategies against arsenic toxicity in edible legume are extremely poor. Main purpose of the present study was to investigate the As-effects and its mitigation by thiourea (TU), a sulfhydryl bioregulator, in lentil. Four widely grown lentil genotypes were grown in nutrient media, supplemented with 30 μM sodium arsenate (As), As + 6.5 mM TU and As + 13 mM TU, keeping an untreated control for 10 d. As severely affected plant dry weight by accumulating in shoots and roots. However, TU application sequestered As in crop roots and prevented up-ward translocation of As. TU coordinately modulated glyoxalase system I and II (Gly I and II) and ascorbate (AsA)-glutathione (GSH) redox, and antioxidant defense enzymes in both leaves and roots of four genotypes. Elevation of Gly system prevented toxic methyl glyoxal overaccumulation whereas stimulated AsA-GSH cycle enzymes and Glutathione s-transferase and catalase effectively scavenged H 2 O 2 and prevented reactive oxygen species (ROS) -mediated onset of oxidative damage in four genotypes, as was evident from ROS-imaging study. Results suggested exogenous TU stimulated the Gly and antioxidant defense in fine tune against As-induced oxidative damage in lentil genotypes.
12 citations
Cites background or result from "Superoxide-Dismutase Deficient Muta..."
...Overproduction of superoxides and H 2 O 2 due to toxic metals/metalloids was distinctly screened by CLSM study in pea, beans, alfalfa, and lupin roots (Ortega-Villasante et al., 2005; Rodr´ıguez-Serrano et al., 2006; Talukdar and Talukdar, 2013)....
[...]
...As-induced reduction in Chl A and Chl A/B ratio was observed in As-exposed edible legumes, cereals, and other crops but unlike the present circumstances in most of these cases carotenoid levels were not affected by As exposure (Guo et al., 2005; Talukdar and Talukdar, 2013; 2014)....
[...]
References
More filters
TL;DR: In this paper, the effects of arsenic on growth and antioxidant metabolism of fenugreek (Trigonella foenum-graecum L. cv. Azad) plants were studied using 10, 20, and 30 mg As/kg of soil in a pot experiment under controlled conditions.
Abstract: The effects of arsenic (As) on growth and antioxidant metabolism of fenugreek (Trigonella foenum-graecum L. cv. Azad) plants were studied using 10, 20, and 30 mg As/kg of soil in a pot experiment under controlled conditions. The length and dry weights of shoots and roots, photosynthetic traits, and grain yield components exhibited a significant increase over control (0 mg As/kg) at As20 but decreased markedly at As30. The cause of this completely reverse response of plant growth between As20 and As30 was investigated in the backdrop of H2O2 metabolism by analyzing responses of three prominent antioxidant enzymes, namely superoxide dismutase (SOD), ascorbate peroxidase (APX), and catalase (CAT) along with cellular ascorbate pool and its redox state. Despite a significant increase in the H2O2 content in both As20 and As30 plants, the former, unlike As30 plants, did not experience any type of As-induced oxidative stress (membrane lipid peroxidation, electrolyte leakage). Normal to high levels of leaf APX, CAT, and redox pool of ascorbate effectively balanced the elevated SOD activity at As20, maintaining the H2O2 concentration higher than control but obviously in favor of As20 plant growth. By contrast, soil amendment with phosphorus (200 mg P/kg) at As30 prevented As-induced oxidative stress through the reduction of the H2O2 level even below As0. The increased enzyme activity was mainly due to the induction of unique Cu/Zn, Fe, and Mn isoforms of SOD and APX-3/APX-4 and/or their increased expression in coordination with CAT. The detection of novel isoforms suggests a strong response of H2O2-metabolizing enzymes against As-induced oxidative stress in fenugreek.
60 citations
Additional excerpts
...aureus, Lathyrus sativus, and Trigonella foenum-graecum [3, 7, 25, 33]....
[...]
01 Jan 2011
TL;DR: Arsenic Response Index (ARI) was developed for the first time in these two crops and exhibited better tolerance to arsenic-induced toxicity than L. sativus L. at the stages of germination and early seedling growth.
Abstract: Effect of five different concentrations (0, 10, 20, 30 and 40 mg/L) of arsenic was studied on 11 different parameters of two important leguminous crops, namely Trigonella foenum-graecum L. (fenugreek) and Lathyrus sativus L. (grass pea) during germination and early seedling growth stage. Mean value of germination percentage, germination index and relative germination rate decreased with concomitant increase in arsenic-induced injury level in increasing concentration of arsenic in both plants and the effect was significant at 30 and 40 mg/L treatments. Fresh and dry weight of shoots, roots and their length also reduced significantly in these two treatment levels. There was significant accumulation of arsenic in tissues, and the effect was more severe on root than shoots. Based on the parameters responding to arsenic-induced stress, Arsenic Response Index (ARI) was developed for the first time in these two crops. Among the two crops, T. foenum-graecum L. exhibited better tolerance to arsenic-induced toxicity than L. sativus L. Considering mean and ARI value, 30 mg/L of arsenic was selected as toxic to L. sativus L., while the limit was 40 mg/L for T. foenum-graecum L. at the stages of germination and early seedling growth.
55 citations
Additional excerpts
...aureus, Lathyrus sativus, and Trigonella foenum-graecum [3, 7, 25, 33]....
[...]
TL;DR: The three dwarf mutants detected were monogenically recessive and bred true in successive generations, and can be utilized as valuable tools for further cytogenetic research and breeding of grass pea.
Abstract: Induction of mutation has been used to create additional genetic variability in grass pea (Lathyrus sativus L.). During the ongoing investigations on different induced-morphological mutants, the author detected three types of dwarf mutants in grass pea. One mutant, designated as dwf1 type was earlier identified in colchicine-induced C2 generation of grass pea variety BioR-231 while the other two, designated as dwf2 and dwf3 were isolated in 250 Gy and 300 Gy gamma ray irradiated M2 progeny of variety ‘BioR-231’ and ‘Hooghly Local’, respectively. As compared to their parental varieties (controls), all the three mutants manifested stunted, erect and determinate stem, early maturity and tolerance to pod shattering habit. The mutants differed from each other, as well as with controls, in number of primary branches, nature of stipules and internodes, length of peduncle, leaflet and seed coat colour, seed yield and seed neurotoxin content. The three dwarf mutants were monogenically recessive and bred true in successive generations. F2 segregation pattern obtained from the crosses involving the three mutants indicated that dwarf mutation in grass pea was controlled by two independent non-allelic genes, assigned as df1 (for dwf1 type), df2 (for dwf2 type) and df3 (for dwf3 type), with the df1 locus being multiple allelic. Primary trisomic analyses revealed the presence of df1/df2 locus on the extra chromosome of trisomic type I, whereas df3 was located on the extra chromosome of type III. Linkage studies involving five other phenotypic markers suggested linked association of df1/df2 locus with lfc (leaflet colour) and wgn (winged internode) and df3 locus with cbl (seed coat colour). Both the loci; however, assorted independently with flower colour and stipule character. The dwarf types can be utilized as valuable tools for further cytogenetic research and breeding of grass pea.
55 citations
"Superoxide-Dismutase Deficient Muta..." refers background in this paper
...Among the legumes, similar phenomenon was observed in catalase-deficient mutants in lentil [11], dwarf mutations, and flavonoid-deficient mutants of grass pea [14, 45]....
[...]
TL;DR: The SGECd(t) mutant represents a novel and unique model to study adaptation of plants to toxic heavy metal concentrations, demonstrating its capability to cope well with increased Cd levels in its tissues.
51 citations
"Superoxide-Dismutase Deficient Muta..." refers background in this paper
...to decipher metal tolerance and accumulation [10, 11], role of ascorbate and glutathione in redox balance and stress tolerance [12, 13], to ascertain genetic basis of flavonoid deficiency [14], to assess gene-dosage effect on antioxidant defense [15], and tolerance to salinity stress [16]....
[...]
TL;DR: The results suggested that asfL-1 plants undertook a major reshuffle in its antioxidant defense machinery, which effectively counterbalanced the negative impact of ascorbate deficiency and remained unperturbed by NaCl treatment to maintain normal growth and biomass production.
Abstract: An ascorbate-deficient semi-dwarf mutant asfL-1 was detected in 250 Gy γ-ray treated grass pea (Lathyrus sativus L.) cv. BioR-231. The mutant contained only 42 % of leaf and 20 % of root ascorbate content of mother control (MC). I investigated the possible causes of ascorbate deficiency and its effect on growth and antioxidant defense in control and 150 mM NaCl-treated seedling after 60 d growth period. Ascorbate deficiency was due to significant reduction in activities of monodehydroascorbate reductase and dehydroascorbate reductase as well as increase in ascorbate oxidase, leading to considerable decrease in redox state. Despite low ascorbate pool and decrease in ascorbate peroxidase activity, shoot and root biomass production in asfL-1 mutant were similar to MC plants, even at NaCl treatment. High accumulation of glutathione (GSH) coupled with high activities of GSH reductase, catalase, GSH peroxidase and peroxidase in both tissues of the mutant permitted efficient recycling of GSH and scavenging of H2O2 through well integrated catalase/peroxidase system, despite high superoxide dismutase activity under NaCl treatment. The collapse of this system led to inhibition of growth in NaCl-treated mother plants. Together, the results suggested that asfL-1 plants undertook a major reshuffle in its antioxidant defense machinery, which effectively counterbalanced the negative impact of ascorbate deficiency and remained unperturbed by NaCl treatment to maintain normal growth and biomass production.
50 citations
"Superoxide-Dismutase Deficient Muta..." refers background in this paper
...to decipher metal tolerance and accumulation [10, 11], role of ascorbate and glutathione in redox balance and stress tolerance [12, 13], to ascertain genetic basis of flavonoid deficiency [14], to assess gene-dosage effect on antioxidant defense [15], and tolerance to salinity stress [16]....
[...]