Abstract Solanum viarum Dunal, is an important medicinal plant widely used as a source of raw mat... more Abstract Solanum viarum Dunal, is an important medicinal plant widely used as a source of raw material for the steroidal drug industry. Out of various steroidal precursors, solasodine, an analogue of diosgenin is the most important source of raw material for the synthesis of steroidal drugs. In the present study, growth and phytochemical variations in different tissue (leaves, stem, roots, and berries) of two contrasting genotypes, prickled and prickleless Solanum viarum were evaluated under in vitro and field conditions. Significant variation in growth, yield and contents of glycoalkaloids, phenolics, and flavonoids were evident between two genotypes under in vitro and field conditions. Prickleless genotypes showed improved growth parameters both under in vitro and field conditions, that helps in contributing to higher yield over prickled plants. Tissue-specific chemical analysis revealed that the leaves and roots of prickleless plants serve as a better repertoire for bioactive phytomolecules. The vegetative parts of in vitro grown 50 days old prickleless plants showed comparable/higher metabolite content than 7–8 month old field-grown plants. Hence it can be used as an alternative production platform for further upscaling, elicitation, and precursor feeding targets that enhances its commercial utility. The expression analysis of seven genes involved in the regulation of important metabolite biosynthesis in both prickled and prickleless genotype of Solanum viarum was also examined. The diverse metabolite profiles are correlated with variations in gene expression profiles. This study provides information about the key metabolites and its biosynthetic pathway genes, which could be useful for the selection of an improved prickleless genotype (“Nishkantak”) of Solanum viarum.
This review highlights the current status of various biotechnological efforts made in Centella as... more This review highlights the current status of various biotechnological efforts made in Centella asiatica (L.) Urban, extensively used medicinal herb in the traditional as well as modern systems of medicines. Published literature on the development and testing of various in vitro cell/tissue/organ culture-based protocols for biomass and metabolites yield enhancement has been compiled and presented here with an intention to identify research gaps that need more closer prospection for their industrial translation and up-scaling. Emphasis has also been laid in listing some of the pathway flux limiting enzymes/genes that demand more concerted efforts for their translational up-regulation in this medicinal herb. Centella asiatica is commonly known as Gotu Kola, Asiatic Pennywort or Brahmi in the herbal trade and is an important constituents of > 100 health care formulations sold in the market. The plant and its chemical constituents are frequently used for the treatment of several nootropic disorders, memory loss, platelets aggregation, insomnia, psoriasis, burn wounds, hypertonic scars, and skin cell reconstruction and curing. Centella derives most of its pharmacological activities from four major bioactive triterpene glycosides namely, asiaticoside, madecassoside, asiatic acid, and madecassic acid (collectively called as centellosides). Plants with at least 2% content of asiaticoside and madecassoside are generally preferred by the herbal industries. In India, 500-1000 MT of Centella herb priced at 0.4-0.5 US dollars/kg is traded annually. Like several other medicinal plants, more than 90% of the supply of C. asiatica herb to the industry is met through collection from the wild strands, which is neither sustainable nor quality-driven. The plant is already included in the International Union for Conservation of Nature and National Resources Red Data book of threatened species. A scan of published literature on C. asiatica clearly indicates that while advances made in the fields of chemistry and bioactivity assessment of centellosides have been regularly reviewed, a compilation of data on tissue culture, pathway modulation and metabolic engineering efforts made in this herb is lacking. The present review is an attempt to fill this gap.
Growth and in vitro asiaticoside accumulation in multiple shoot cultures of Centella asiatica (L.... more Growth and in vitro asiaticoside accumulation in multiple shoot cultures of Centella asiatica (L.) Urban was studied as a function of nutrient manipulations in the culture media. Shoot cultures raised in liquid Murashige and Skoog medium supplemented with 2.5 mg/l kinetin attained a growth index (GI) of 6.06 along with the highest asiaticoside content of 3.8 mg/g dry weight on the 35th day of the culture cycle. The shoot growth and asiaticoside accumulation were found to be influenced by the relative proportions of NH 4 ?-N:NO 3-N or Cu 2? concentration in the medium. Asiaticoside content in shoots increased from 5.3 to 8.9 and 8.7 mg/g dry weight when total nitrogen concentration of 60 mM in the control medium was reduced to 50 and 40 mM with a corresponding change in NH 4 ? :NO 3 ratio from 20:40 to 20:30 or 20:20, respectively. Total nitrogen level higher than 60 mM drastically reduced the asiaticoside concentration in these in vitro shoot cultures. Medium devoid of Cu 2? significantly favored higher asiaticoside accumulation in the cultured tissue (7.05 mg/g dry weight) along with an improved biomass production (GI = 7.7) when compared with shoots reared on the control medium with 0.10 lM Cu 2? (GI = 5.8; asiaticoside content = 4.4 mg/g dry weight). Carbohydrate enrichment of the medium by increasing the sucrose concentration from 3.0 to 5.0 or 7.0% was also beneficial for biomass and asiaticoside production with GI = 17.1 and 16.9 and asiaticoside content = 7.2 and 5.2 mg/g dry weight, respectively, in comparison to control cultures maintained on medium containing 3.0% sucrose. The procedure described here provides a viable production platform for generating clean and quality material from Centella with high bioactive content.
Effect of fungal elicitors on biomass and asiaticoside production in multiple shoot cultures of C... more Effect of fungal elicitors on biomass and asiaticoside production in multiple shoot cultures of Centella asiatica was studied in a dose-and culture age-dependent manner. Addition of 3 % v/v Trichoderma harzianum culture filtrate (CF) in the growth medium on 10th day of 35 days culture cycle resulted in 9.63 mg g-1 dry weight content and 1.15 mg dry weight culture-1 yield of asiaticoside that was 2.53 and 2.35 times higher than in the unelicited control shoots, respectively. The elicited cultures also registered 1.24 folds more biomass over the control with a growth index (GI) of 7.67, calculated as fresh weight increment over the initial inoculum weight. Elicitation of shoots with mycelial extract (ME) of the fungus Colletotrichum lindemuthianum (1.5 % v/v, added on 0 day) on the other hand, though favored highest biomass accumulation amongst all the elicitation treatments (GI = 16.10) resulted in a decreased asiaticoside content of 1.10 mg g-1 dry weight that was nearly 3.5 and 8.7 times lower than in the control or T. harzianum CF-treated shoots, respectively. Treatments with mycelial extract of Fusarium oxysporum (0.5-1.5 % v/v), in general, proved inhibitory for shoot growth if added on 0 day of the culture cycle with GI = 4.85-8.45 in comparison to 11.11 in the control with a poor asiaticoside yield of only 0.18-0.42 mg dry weight culture-1. Though the shoot biomass accumulation was marginally improved (GI = 5.68-11.94) over the untreated control when F. oxysporum ME (0.5-1.5 % v/v) was added in the medium on the 30th day of culture but the asiaticoside yield (0.18-0.94 mg dry weight culture-1) remained low. The results presented here demonstrate for the first time the potential application of T. harzianum CF in upregulating the asiaticoside biogenetic pathway in C. asiatica.
Conditions to cultivate medicinally important herb Centella asiatica in hydroponic system are rep... more Conditions to cultivate medicinally important herb Centella asiatica in hydroponic system are reported here for the first time. Growth kinetics of hydroponically grown plants was monitored over a period of 70 days. The maximum growth and dry matter accumulation (156.3% increment over the initial inoculum weight) in the cultured plants occurred around 42nd day. High Performance Liquid Chromatography (HPLC) analysis of the bioactive centellosides in the crude triterpenoids extract of the harvested leaves showed the presence of 11 mg, 1.7 mg, 36.6 mg and 6.3 mg of madecassoside, asiaticoside, madecassic acid and asiatic acid on per gram dry weight basis, respectively. The results of this study suggest that the cultivation of C. asiatica in hydroponic systems can be an effective platform for the production of clean and good quality C. asiatica herb for the pharmaceutical companies.
the present study can be further used to provide better production of high value, in demand cente... more the present study can be further used to provide better production of high value, in demand centellosides.
An artificial neural network (ANN)-based modelling approach is used to determine the synergistic ... more An artificial neural network (ANN)-based modelling approach is used to determine the synergistic effect of five major components of growth medium (Mg, Cu, Zn, nitrate and sucrose) on improved in vitro biomass yield in multiple shoot cultures of Centella asiatica. The back propagation neural network (BPNN) was employed to predict optimal biomass accumulation in terms of growth index over a defined culture duration of 35 days. The four variable concentrations of five media components, i.e. MgSO4 (0, 0.75, 1.5, 3.0 mM), ZnSO4 (0, 15, 30, 60 μM), CuSO4 (0, 0.05, 0.1, 0.2 μM), NO3 (20, 30, 40, 60 mM) and sucrose (1, 3, 5, 7 %, w/v) were taken as inputs for the ANN model. The designed model was evaluated by performing three different sets of validation experiments that indicated a greater similarity between the target and predicted dataset. The results of the modelling experiment suggested that 1.5 mM Mg, 30 μM Zn, 0.1 μM Cu, 40 mM NO3 and 6 % (w/v) sucrose were the respective optimal concentrations of the tested medium components for achieving maximum growth index of 1654.46 with high centelloside yield (62.37 mg DW/culture) in the cultured multiple shoots. This study can facilitate the generation of higher biomass of uniform, clean, good quality C. asiatica herb that can efficiently be utilized by pharmaceutical industries.
Cassia angustifolia Vahl is known for the production of leaves and pod shells containing high-val... more Cassia angustifolia Vahl is known for the production of leaves and pod shells containing high-value glycosides (sennosides) with enormous medicinal properties to cure constipation in all over the world. However, data on its agricultural practices is limited. The present study aim to optimize the sowing time, moisture regime, and harvesting date at subtropical conditions for getting maximum marketable produce. Experiments were performed over two years (2016 and 2017) into two sets. First one comprised of seven dates of sowing, and second experiments having four moisture regimes and four dates of harvest. In subtropical north Indian conditions, 15 March was the best sowing date with highest biological yield (17.446 q ha −1), sennoside content (2.18% in leaves and 3.26% in pods), and sennoside yield (45.943 kg ha −1). The 20% available soil moisture with 90 days of harvesting time was suitable for the maximum biological yield of senna (17.296 q ha −1). The maximum net return (67,989.0 Rs ha −1) was observed at 20% available soil Moisture (ASM) condition at 90 days harvesting. Hence, the study recommended that the 15 March sowing date, 20% available soil moisture and 90 days harvest for the Cassia angustifolia Vahl. provide more income to the farmers and industry. Development of cost-effective package of practices leading to the quality assurance will encourage its cultivation and availability of raw material to the industry.
Centella asiatica germplasm collected from north, north-eastern and southern parts of India was c... more Centella asiatica germplasm collected from north, north-eastern and southern parts of India was compared for biomass and centellosides productivity under uniform agro-climatic conditions of the Indo-Gangetic plains at Lucknow. The highest biomass accumulation (411.9 g FW/m2 area) was recorded in accession A from north India, followed by 284.0, 135.7 and 29.2 g FW/m2 in accessions M, B and E from southern, eastern and north-eastern regions, respectively. Accession M possessed the highest asiaticoside content (52.1 mg/gDW) that was 1.58, 2.34 and 21.7 folds more than accessions A, B and E, respectively. The madecassoside level in leaves of accessions B and M was comparable (28.9 and 25.7 mg/gDW) and two folds more than accession A (13.9 mg/gDW). The madecassic and asiatic acid content in leaf tissue of all four accessions remained low in Lucknow. Amplified fragment length polymorphism (AFLP) analysis with 23 primers yielded 696 fragments, 563 of which were polymorphic. Accession M out...
In vitro grown callus and seedlings of Brassica juncea were treated with equimolar concentrations... more In vitro grown callus and seedlings of Brassica juncea were treated with equimolar concentrations of cadmium and compared for their respective tolerance to cadmium. Calli cultures were grown on Murashige and Skoog medium supplemented with α 6-benzyl aminopurine (200 µg L−1, naphthalene acetic acid 200 µg L−1) and 2,4-dichloro-phenoxy acetic acid (65 µg L−1) while the seedlings grown on Hoagland's nutrient solution have been carried out. Cellular homeostasis and detoxification to cadmium in B. juncea were studied by analyzing the growth in terms of fresh weight and dry weight, lipid peroxidation, proline accumulation, and antioxidative enzymes (superoxide dismutase (SOD), ascorbate peroxidase (APX), and catalase (CAT)). At 200 µM cadmium, callus and seedlings showed 73.61% and 74.76% reduction in tolerance, respectively. A significant increase in malondialdehyde (MDA) content was found in both calli and seedlings; however, the amount of MDA content was more in seedlings. Proline content increased on lower concentration of cadmium (up to 50 µM), and it further decreased (up to 200 µM). But the accumulation of proline was higher in callus cultures. The overall activity of antioxidative enzymes (SOD, CAT, and APX) was found to be higher in callus in comparison to seedlings of B. juncea. Callus and seedlings showed a significant (P ≤ 0.5) increase in SOD activity in a concentration-dependent manner up to 50 µM cadmium concentration but decreased further. APX activity increased significantly at low cadmium levels but CAT activity decreased significantly throughout on increasing cadmium concentrations from 5 to 200 µM, respectively. Hence, it was observed that callus of B. juncea was more tolerant in comparison to seedlings exposed to equimolar concentrations of cadmium. Thus, from the present studies, it is concluded that calli were more tolerant toward cadmium-induced oxidative stress. Hence, it is suitable material for the study of cadmium tolerance mechanisms and for the manipulations within them for better understanding of cadmium detoxification strategies in B. juncea.
Abstract Solanum viarum Dunal, is an important medicinal plant widely used as a source of raw mat... more Abstract Solanum viarum Dunal, is an important medicinal plant widely used as a source of raw material for the steroidal drug industry. Out of various steroidal precursors, solasodine, an analogue of diosgenin is the most important source of raw material for the synthesis of steroidal drugs. In the present study, growth and phytochemical variations in different tissue (leaves, stem, roots, and berries) of two contrasting genotypes, prickled and prickleless Solanum viarum were evaluated under in vitro and field conditions. Significant variation in growth, yield and contents of glycoalkaloids, phenolics, and flavonoids were evident between two genotypes under in vitro and field conditions. Prickleless genotypes showed improved growth parameters both under in vitro and field conditions, that helps in contributing to higher yield over prickled plants. Tissue-specific chemical analysis revealed that the leaves and roots of prickleless plants serve as a better repertoire for bioactive phytomolecules. The vegetative parts of in vitro grown 50 days old prickleless plants showed comparable/higher metabolite content than 7–8 month old field-grown plants. Hence it can be used as an alternative production platform for further upscaling, elicitation, and precursor feeding targets that enhances its commercial utility. The expression analysis of seven genes involved in the regulation of important metabolite biosynthesis in both prickled and prickleless genotype of Solanum viarum was also examined. The diverse metabolite profiles are correlated with variations in gene expression profiles. This study provides information about the key metabolites and its biosynthetic pathway genes, which could be useful for the selection of an improved prickleless genotype (“Nishkantak”) of Solanum viarum.
This review highlights the current status of various biotechnological efforts made in Centella as... more This review highlights the current status of various biotechnological efforts made in Centella asiatica (L.) Urban, extensively used medicinal herb in the traditional as well as modern systems of medicines. Published literature on the development and testing of various in vitro cell/tissue/organ culture-based protocols for biomass and metabolites yield enhancement has been compiled and presented here with an intention to identify research gaps that need more closer prospection for their industrial translation and up-scaling. Emphasis has also been laid in listing some of the pathway flux limiting enzymes/genes that demand more concerted efforts for their translational up-regulation in this medicinal herb. Centella asiatica is commonly known as Gotu Kola, Asiatic Pennywort or Brahmi in the herbal trade and is an important constituents of > 100 health care formulations sold in the market. The plant and its chemical constituents are frequently used for the treatment of several nootropic disorders, memory loss, platelets aggregation, insomnia, psoriasis, burn wounds, hypertonic scars, and skin cell reconstruction and curing. Centella derives most of its pharmacological activities from four major bioactive triterpene glycosides namely, asiaticoside, madecassoside, asiatic acid, and madecassic acid (collectively called as centellosides). Plants with at least 2% content of asiaticoside and madecassoside are generally preferred by the herbal industries. In India, 500-1000 MT of Centella herb priced at 0.4-0.5 US dollars/kg is traded annually. Like several other medicinal plants, more than 90% of the supply of C. asiatica herb to the industry is met through collection from the wild strands, which is neither sustainable nor quality-driven. The plant is already included in the International Union for Conservation of Nature and National Resources Red Data book of threatened species. A scan of published literature on C. asiatica clearly indicates that while advances made in the fields of chemistry and bioactivity assessment of centellosides have been regularly reviewed, a compilation of data on tissue culture, pathway modulation and metabolic engineering efforts made in this herb is lacking. The present review is an attempt to fill this gap.
Growth and in vitro asiaticoside accumulation in multiple shoot cultures of Centella asiatica (L.... more Growth and in vitro asiaticoside accumulation in multiple shoot cultures of Centella asiatica (L.) Urban was studied as a function of nutrient manipulations in the culture media. Shoot cultures raised in liquid Murashige and Skoog medium supplemented with 2.5 mg/l kinetin attained a growth index (GI) of 6.06 along with the highest asiaticoside content of 3.8 mg/g dry weight on the 35th day of the culture cycle. The shoot growth and asiaticoside accumulation were found to be influenced by the relative proportions of NH 4 ?-N:NO 3-N or Cu 2? concentration in the medium. Asiaticoside content in shoots increased from 5.3 to 8.9 and 8.7 mg/g dry weight when total nitrogen concentration of 60 mM in the control medium was reduced to 50 and 40 mM with a corresponding change in NH 4 ? :NO 3 ratio from 20:40 to 20:30 or 20:20, respectively. Total nitrogen level higher than 60 mM drastically reduced the asiaticoside concentration in these in vitro shoot cultures. Medium devoid of Cu 2? significantly favored higher asiaticoside accumulation in the cultured tissue (7.05 mg/g dry weight) along with an improved biomass production (GI = 7.7) when compared with shoots reared on the control medium with 0.10 lM Cu 2? (GI = 5.8; asiaticoside content = 4.4 mg/g dry weight). Carbohydrate enrichment of the medium by increasing the sucrose concentration from 3.0 to 5.0 or 7.0% was also beneficial for biomass and asiaticoside production with GI = 17.1 and 16.9 and asiaticoside content = 7.2 and 5.2 mg/g dry weight, respectively, in comparison to control cultures maintained on medium containing 3.0% sucrose. The procedure described here provides a viable production platform for generating clean and quality material from Centella with high bioactive content.
Effect of fungal elicitors on biomass and asiaticoside production in multiple shoot cultures of C... more Effect of fungal elicitors on biomass and asiaticoside production in multiple shoot cultures of Centella asiatica was studied in a dose-and culture age-dependent manner. Addition of 3 % v/v Trichoderma harzianum culture filtrate (CF) in the growth medium on 10th day of 35 days culture cycle resulted in 9.63 mg g-1 dry weight content and 1.15 mg dry weight culture-1 yield of asiaticoside that was 2.53 and 2.35 times higher than in the unelicited control shoots, respectively. The elicited cultures also registered 1.24 folds more biomass over the control with a growth index (GI) of 7.67, calculated as fresh weight increment over the initial inoculum weight. Elicitation of shoots with mycelial extract (ME) of the fungus Colletotrichum lindemuthianum (1.5 % v/v, added on 0 day) on the other hand, though favored highest biomass accumulation amongst all the elicitation treatments (GI = 16.10) resulted in a decreased asiaticoside content of 1.10 mg g-1 dry weight that was nearly 3.5 and 8.7 times lower than in the control or T. harzianum CF-treated shoots, respectively. Treatments with mycelial extract of Fusarium oxysporum (0.5-1.5 % v/v), in general, proved inhibitory for shoot growth if added on 0 day of the culture cycle with GI = 4.85-8.45 in comparison to 11.11 in the control with a poor asiaticoside yield of only 0.18-0.42 mg dry weight culture-1. Though the shoot biomass accumulation was marginally improved (GI = 5.68-11.94) over the untreated control when F. oxysporum ME (0.5-1.5 % v/v) was added in the medium on the 30th day of culture but the asiaticoside yield (0.18-0.94 mg dry weight culture-1) remained low. The results presented here demonstrate for the first time the potential application of T. harzianum CF in upregulating the asiaticoside biogenetic pathway in C. asiatica.
Conditions to cultivate medicinally important herb Centella asiatica in hydroponic system are rep... more Conditions to cultivate medicinally important herb Centella asiatica in hydroponic system are reported here for the first time. Growth kinetics of hydroponically grown plants was monitored over a period of 70 days. The maximum growth and dry matter accumulation (156.3% increment over the initial inoculum weight) in the cultured plants occurred around 42nd day. High Performance Liquid Chromatography (HPLC) analysis of the bioactive centellosides in the crude triterpenoids extract of the harvested leaves showed the presence of 11 mg, 1.7 mg, 36.6 mg and 6.3 mg of madecassoside, asiaticoside, madecassic acid and asiatic acid on per gram dry weight basis, respectively. The results of this study suggest that the cultivation of C. asiatica in hydroponic systems can be an effective platform for the production of clean and good quality C. asiatica herb for the pharmaceutical companies.
the present study can be further used to provide better production of high value, in demand cente... more the present study can be further used to provide better production of high value, in demand centellosides.
An artificial neural network (ANN)-based modelling approach is used to determine the synergistic ... more An artificial neural network (ANN)-based modelling approach is used to determine the synergistic effect of five major components of growth medium (Mg, Cu, Zn, nitrate and sucrose) on improved in vitro biomass yield in multiple shoot cultures of Centella asiatica. The back propagation neural network (BPNN) was employed to predict optimal biomass accumulation in terms of growth index over a defined culture duration of 35 days. The four variable concentrations of five media components, i.e. MgSO4 (0, 0.75, 1.5, 3.0 mM), ZnSO4 (0, 15, 30, 60 μM), CuSO4 (0, 0.05, 0.1, 0.2 μM), NO3 (20, 30, 40, 60 mM) and sucrose (1, 3, 5, 7 %, w/v) were taken as inputs for the ANN model. The designed model was evaluated by performing three different sets of validation experiments that indicated a greater similarity between the target and predicted dataset. The results of the modelling experiment suggested that 1.5 mM Mg, 30 μM Zn, 0.1 μM Cu, 40 mM NO3 and 6 % (w/v) sucrose were the respective optimal concentrations of the tested medium components for achieving maximum growth index of 1654.46 with high centelloside yield (62.37 mg DW/culture) in the cultured multiple shoots. This study can facilitate the generation of higher biomass of uniform, clean, good quality C. asiatica herb that can efficiently be utilized by pharmaceutical industries.
Cassia angustifolia Vahl is known for the production of leaves and pod shells containing high-val... more Cassia angustifolia Vahl is known for the production of leaves and pod shells containing high-value glycosides (sennosides) with enormous medicinal properties to cure constipation in all over the world. However, data on its agricultural practices is limited. The present study aim to optimize the sowing time, moisture regime, and harvesting date at subtropical conditions for getting maximum marketable produce. Experiments were performed over two years (2016 and 2017) into two sets. First one comprised of seven dates of sowing, and second experiments having four moisture regimes and four dates of harvest. In subtropical north Indian conditions, 15 March was the best sowing date with highest biological yield (17.446 q ha −1), sennoside content (2.18% in leaves and 3.26% in pods), and sennoside yield (45.943 kg ha −1). The 20% available soil moisture with 90 days of harvesting time was suitable for the maximum biological yield of senna (17.296 q ha −1). The maximum net return (67,989.0 Rs ha −1) was observed at 20% available soil Moisture (ASM) condition at 90 days harvesting. Hence, the study recommended that the 15 March sowing date, 20% available soil moisture and 90 days harvest for the Cassia angustifolia Vahl. provide more income to the farmers and industry. Development of cost-effective package of practices leading to the quality assurance will encourage its cultivation and availability of raw material to the industry.
Centella asiatica germplasm collected from north, north-eastern and southern parts of India was c... more Centella asiatica germplasm collected from north, north-eastern and southern parts of India was compared for biomass and centellosides productivity under uniform agro-climatic conditions of the Indo-Gangetic plains at Lucknow. The highest biomass accumulation (411.9 g FW/m2 area) was recorded in accession A from north India, followed by 284.0, 135.7 and 29.2 g FW/m2 in accessions M, B and E from southern, eastern and north-eastern regions, respectively. Accession M possessed the highest asiaticoside content (52.1 mg/gDW) that was 1.58, 2.34 and 21.7 folds more than accessions A, B and E, respectively. The madecassoside level in leaves of accessions B and M was comparable (28.9 and 25.7 mg/gDW) and two folds more than accession A (13.9 mg/gDW). The madecassic and asiatic acid content in leaf tissue of all four accessions remained low in Lucknow. Amplified fragment length polymorphism (AFLP) analysis with 23 primers yielded 696 fragments, 563 of which were polymorphic. Accession M out...
In vitro grown callus and seedlings of Brassica juncea were treated with equimolar concentrations... more In vitro grown callus and seedlings of Brassica juncea were treated with equimolar concentrations of cadmium and compared for their respective tolerance to cadmium. Calli cultures were grown on Murashige and Skoog medium supplemented with α 6-benzyl aminopurine (200 µg L−1, naphthalene acetic acid 200 µg L−1) and 2,4-dichloro-phenoxy acetic acid (65 µg L−1) while the seedlings grown on Hoagland's nutrient solution have been carried out. Cellular homeostasis and detoxification to cadmium in B. juncea were studied by analyzing the growth in terms of fresh weight and dry weight, lipid peroxidation, proline accumulation, and antioxidative enzymes (superoxide dismutase (SOD), ascorbate peroxidase (APX), and catalase (CAT)). At 200 µM cadmium, callus and seedlings showed 73.61% and 74.76% reduction in tolerance, respectively. A significant increase in malondialdehyde (MDA) content was found in both calli and seedlings; however, the amount of MDA content was more in seedlings. Proline content increased on lower concentration of cadmium (up to 50 µM), and it further decreased (up to 200 µM). But the accumulation of proline was higher in callus cultures. The overall activity of antioxidative enzymes (SOD, CAT, and APX) was found to be higher in callus in comparison to seedlings of B. juncea. Callus and seedlings showed a significant (P ≤ 0.5) increase in SOD activity in a concentration-dependent manner up to 50 µM cadmium concentration but decreased further. APX activity increased significantly at low cadmium levels but CAT activity decreased significantly throughout on increasing cadmium concentrations from 5 to 200 µM, respectively. Hence, it was observed that callus of B. juncea was more tolerant in comparison to seedlings exposed to equimolar concentrations of cadmium. Thus, from the present studies, it is concluded that calli were more tolerant toward cadmium-induced oxidative stress. Hence, it is suitable material for the study of cadmium tolerance mechanisms and for the manipulations within them for better understanding of cadmium detoxification strategies in B. juncea.
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