Cancer is a major cause of death worldwide, with an increasing number of cases being reported ann... more Cancer is a major cause of death worldwide, with an increasing number of cases being reported annually. The elevated rate of mortality necessitates a global challenge to explore newer sources of anticancer drugs. Recent advancements in cancer treatment involve the discovery and development of new and improved chemotherapeutics derived from natural or synthetic sources. Natural sources offer the potential of finding new structural classes with unique bioactivities for cancer therapy. Endophytic fungi represent a rich source of bioactive metabolites that can be manipulated to produce desirable novel analogs for chemotherapy. This review offers a current and integrative account of clinically used anticancer drugs such as taxol, podophyllotoxin, camptothecin, and vinca alkaloids in terms of their mechanism of action, isolation from endophytic fungi and their characterization, yield obtained, and fungal strain improvement strategies. It also covers recent literature on endophytic fungal metabolites from terrestrial, mangrove, and marine sources as potential anticancer agents and emphasizes the findings for cytotoxic bioactive compounds tested against specific cancer cell lines.
The prospective of endophytic microorganisms allied with medicinal plants is disproportionally la... more The prospective of endophytic microorganisms allied with medicinal plants is disproportionally large compared to those in other biomes. The use of antagonistic microorganisms to control devastating fungal pathogens is an attractive and eco-friendly substitute for chemical pesticides. Many species of actinomycetes, especially the genus Streptomyces, are well known as biocontrol agents. We investigated the culturable community composition and biological control ability of endophytic Streptomyces sp. associated with an ethanobotanical plant Schima wallichi. A total of 22 actinobacterial strains were isolated from different organs of selected medicinal plants and screened for their biocontrol ability against seven fungal phytopathogens. Seven isolates showed significant inhibition activity against most of the selected pathogens. Their identification based on 16S rRNA gene sequence analysis, strongly indicated that all strains belonged to the genus Strepto myces. An endophytic strain BPS...
The genus Streptomyces under phylum actinobacteria has been recognized as a prolific source for t... more The genus Streptomyces under phylum actinobacteria has been recognized as a prolific source for the production of bioactive secondary metabolites. An actinobacterial strain designated as DST103 isolated from a wetland fresh water sediment of Tamdil Lake, Mizoram, Northeast, India was identified as Streptomyces cyaneofuscatus (KY287599) using 16SrRNA gene sequencing which shares 99.87% sequence similarity with Streptomyces cyaneofuscatus NRRL B-2570 (T) . The strain showed broad spectrum antimicrobial activities against Gram negative bacteria (Escherichia coli MTCC 739 and Pseudomonas aeruginosa MTCC 2453), Gram positive bacteria (Micrococcus luteus NCIM 2170 and Staphylococcus aureus MTCC 96) and yeast pathogen Candida albicans MTCC 3017). The methanolic extract of the strain DST103 exhibited highest antimicrobial activity against E. coli (IC50 = 2.10 μg/mL) and minimum activity against S. aureus (IC50 = 43.63 μg/mL). Five antibiotics [trimethoprim (18 μg/g), fluconazole (6 μg/g), k...
Antimicrobial resistance poses a serious challenge to global public health. In this study, fifty ... more Antimicrobial resistance poses a serious challenge to global public health. In this study, fifty bacterial strains were isolated from the sediments of a freshwater lake and were screened for antibiotic resistance. Out of fifty isolates, thirty-three isolates showed resistance against at least two of the selected antibiotics. Analysis of 16S rDNA sequencing revealed that the isolates belonged to ten different genera, namely Staphylococcus(n = 8), Bacillus(n = 7), Lysinibacillus(n = 4), Achromobacter(n=3), bacterium(n = 3), Methylobacterium(n = 2), Bosea(n = 2), Aneurinibacillus(n = 2), Azospirillum(n = 1), Novosphingobium(n = 1). Enterobacterial repetitive intergenic consensus (ERIC) and BOX-PCR markers were used to study the genetic relatedness among the antibiotic resistant isolates. Further, the isolates were screened for their antimicrobial activity against bacterial pathogens viz., Staphylococcus aureus(MTCC-96), Pseudomonas aeruginosa(MTCC-2453) and Escherichia coli(MTCC-739), ...
Information on rhizosphere microbiome of endemic plants from high mountain ecosystems against tho... more Information on rhizosphere microbiome of endemic plants from high mountain ecosystems against those of cultivated plantations is inadequate. Comparative bacterial profiles of endemic medicinal plant Rhododendron arboreum Sm. subsp. delavayi rhizosphere pertaining to four altitudinal zonation Pankang Thang (PTSO), Nagula, Y-junction and Bum La (Indo-China border; in triplicates each) along cold adapted Eastern slope of Himalayan Tawang region, India is described here. Significant differences in DGGE profile between below ground bulk vs. rhizospheric community profile associated with the plant was identified. Tagged 16S amplicon sequencing from PTSO (3912 m) to Bum La (4509 m), revealed that soil pH, total nitrogen (TN), organic matter (OM) significantly influenced the underlying bacterial community structure at different altitudes. The relative abundance of Acidobacteria was inversely related to pH, as opposed to TN which was positively correlated to Acidobacteria and Proteobacteria ...
Journal of environmental biology / Academy of Environmental Biology, India, 2016
Distributions of endophytic fungi associated with ethnomedicinal plant Melastoma malabathricum L.... more Distributions of endophytic fungi associated with ethnomedicinal plant Melastoma malabathricum L. was studied and 91 isolates belonging to 18 genera were recovered. The isolates were distributed to sordariomycetes (62.63%), dothideomycetes (19.78%), eurotiomycetes (7.69%), zygomycetes (4.19%), agaricomycetes (1.09%), and mycelia sterilia (4.39%). Based on colony morphology and examination of spores, the isolates were classified into 18 taxa, of which Colletotrichum, Phomopsis and Phoma were dominant, their relative frequencies were 23.07%, 17.58% and 12.08% respectively. The colonization rate of endophytic fungi was determined and found to be significantly higher in leaf segments (50.76%), followed by root (41.53%) and stem tissues (27.69%). All the isolates were screened for antimicrobial activity and revealed that 26.37% endophytic fungi were active against one or more pathogens. Twenty four isolates showing significant antimicrobial activity were identified by sequencing the ITS1...
The perennial grasses are considered as a rich source of lignocellulosic biomass, making it a sec... more The perennial grasses are considered as a rich source of lignocellulosic biomass, making it a second generation alternative energy source and can diminish the use of fossil fuels. In this work, four perennial grasses Saccharum arundinaceum, Panicum antidotale, Thysanolaena latifolia, and Neyraudia reynaudiana were selected to verify their potential as a substrate to produce hydrolytic enzymes and to evaluate them as second generation energy biomass. Here, cellulase and hemi-cellulase producing three endophytic bacteria (Burkholderia cepacia BPS-GB3, Alcaligenes faecalis BPS-GB5 and Enterobacter hormaechei BPS-GB8) recovered from N. reynaudiana and S. arundinaceum were selected to develop a triculture (CC3) consortium. During 12 days of submerged cultivation, a 55-70% loss in dry weight was observed and the maximum activity of β-glucosidase (5.36-12.34 IU) and Xylanase (4.33 to 10.91 IU) were observed on 2nd and 6th day respectively, whereas FPase (0.26 to 0.53 IU) and CMCase (2.31 t...
The present paper deals with the electrical characterization of sputtered ZrO 2 /Si interface dep... more The present paper deals with the electrical characterization of sputtered ZrO 2 /Si interface deposited in N 2 containing plasma. Incorporation of nitrogen in the sputter deposited films was confirmed by glancing angle X-Ray diffraction measurement. MOS C-V and I-V techniques were used for interface characterization. Nitrogen incorporated ZrO 2 MOS capacitors exhibited higher breakdown voltage and lower leakage current than structures having ZrO 2 dielectric films sputtered in pure argon atmosphere. Different device parameters such as flat band voltage, leakage current, breakdown voltage, charge defects were extracted and compared with and without nitrogen incorporated ZrO 2 /Si MOS capacitor structures. The effect of post deposition annealing on the electrical behavior of ZrO 2 /Si interface was also investigated.
In the present paper, an attempt has been made to examine variations of rice production in differ... more In the present paper, an attempt has been made to examine variations of rice production in different categories of the farmers. A study on economics of rice production in Jhansi district of Uttar Pradesh was conducted for analysis the cost of inputoutput in rice production. The study covered five villages of Jhansi district and data on constraints and cost-return aspects of rice cultivation were collected from 100 farmers. The overall input-output ratio at cost A 1 /A 2 , cost B 1 , cost B 2 , cost C 1 and cost C 2 were 1:3.37, 1:2.56, 1:1.77, 1:1.96 and 1:1.46, respectively. Rice returns to scale on marginal, small, medium and large farmers characterized by decreasing return to scale. For seed, manure and fertilizers and irrigation on all the four categories of farmers, the marginal value productivities were positive and more than unity indicating further scope to increase the investment. Major constraints in rice production as perceived by the farmers were financial related problem (44%), technical related problem (40%), miscellaneous related problem (31%) and management problem (28%).
Fusarium wilt and charcoal rot diseases. The dose effect of 0.01 to 20 mM riboflavin showed that ... more Fusarium wilt and charcoal rot diseases. The dose effect of 0.01 to 20 mM riboflavin showed that 1.0 mM concentration was sufficient for maximum induction of resistance; higher concentration did not increase the effect. At this concentration, riboflavin neither caused cell death of the host plant nor directly affected the pathogen's growth. In time course observation, it was observed that riboflavin treated chickpea plants were inducing resistance 2 days after treatment and reached its maximum level from 5 to 7 days and then decreased. Riboflavin had no effect on salicylic acid (SA) levels in chickpea, however, riboflavin induced plants found accumulation of phenols and a greater activities of phenylalanine ammonia lyase (PAL) and pathogenesis related (PR) protein, peroxidase was observed in induced plant than the control. Riboflavin pre-treated plants challenged with the pathogens exhibited maximum activity of the peroxidases 4 days after treatment. Molecular weight of the purified peroxidase was 42 kDa. From these studies we demonstrated that riboflavin induced resistance is PRprotein mediated but is independent of salicylic acid.
In order to elucidate the elicitor properties of cell-wall protein (CWP) of Fusarium oxysporum f.... more In order to elucidate the elicitor properties of cell-wall protein (CWP) of Fusarium oxysporum f. sp. ciceri and Macrophomina phaseolina, CWPs were extracted and tested against chickpea. The chickpea seedlings exposed to CWPs showed enhanced synthesis of phenol, pathogenesis-related protein and activities of phenylalanine ammonia lyase and peroxidase relative to water-treated controls. Both Fusarium wilt and charcoal rot diseases of chickpea were significantly reduced in seedlings following CWP treatment. However, the same CWPs failed to antagonise the same pathogens in petri dish assays. The results suggest that CWPs of Fusarium and Macrophomina have elicitor properties and effectively induced resistance in chickpea.
Thirty isolates of Fusarium oxysporum f. sp. ciceri were isolated from rhizosphere soil of chickp... more Thirty isolates of Fusarium oxysporum f. sp. ciceri were isolated from rhizosphere soil of chickpea from different locations in Northern India. The amount of genetic variation was evaluated by polymerase chain reaction (PCR) amplification with a set of 40 RAPD primers and 2 IGS primers. Less than 10% of the amplified fragments in each case were polymorphic. Genetic similarity between each of the isolates was calculated and results indicate that there was little genetic variability among the isolates collected from the different locations. At the 0.75 similarity index the isolates divides into three groups. Isolates Foc-A18, Foc-A19, Foc-A20 forming a similar group and far different from other isolates.
Fusarium wilt caused by Fusarium oxysporum f. sp. ciceri causes considerable yield loss of chickp... more Fusarium wilt caused by Fusarium oxysporum f. sp. ciceri causes considerable yield loss of chickpea. Pseudomonas fluorescens4-92 (Pf4-92) strain can suppress the disease. Amendment of zinc EDTA and copper EDTA could not suppress the disease significantly when used alone; however, they significantly suppressed the disease in presence of Pf4-92. In vitro observation showed that at 40, 30 and 20 mg ml À1 concentrations of these minerals, i.e. Zn, Cu and Zn plus Cu, respectively, completely repressed the production of the phytotoxin, fusaric acid (FA). FA concentration (0.5 mg ml À1 ) has been shown to suppress the production of 2,4diacetylphloroglucinol (DAPG) by Pf4-92, and DAPG, salicylic acid, pyochelin and pyoluteorin production was enhanced by these mineral amendments. In rockwool bioassays, Zn, Cu and Zn plus Cu amendments reduced FA production and enhanced DAPG production. This study demonstrates that Zn and Cu enhance biocontrol activity by reducing FA produced by the pathogen, F.
In the high altitude areas of western Himalaya, barley is a crop of marginal, low input drought s... more In the high altitude areas of western Himalaya, barley is a crop of marginal, low input drought stressed environments. The landraces grown in these areas are favoured for their quality, both as grain and straw. However, area under the naked barley landraces, during the last three to four decades, has declined considerably and their ex situ and in situ conservation requires attention. Morphological and RAPD descriptors of a collection of 70 landraces from the higher Himalayan ranges of Uttaranchal state were used to analyse levels of genetic diversity. A wide range of variation was recorded for various morphological characters in univariate analysis. The multivariate analysis based on six quantitative traits distinguished accessions from different geographical areas in the region but failed to separate naked from covered barleys. Clustering based on qualitative traits, however, clearly distinguished naked and covered forms. RAPD profiles efficiently differentiated naked barleys from covered forms, but could not differentiate between oriental and occidental covered forms. A set of 11 predominant landraces were subjected to detailed population genetic analysis. More diversity was observed in covered barleys than the naked forms, both for morphological and RAPD markers. The low diversity in naked barley populations was attributed to either genetic drift or to a founder effect, while the high diversity in covered barley populations was attributed to their large-scale cultivation for animal feed and brewing purposes. Allelic combinations were not randomly distributed, as a geographic trend was closely related to covered and naked barleys. Since naked barleys are poorly represented in the national collections, a systematic collection from the entire region is suggested. The genetic differences between covered and naked barleys may be relevant to breeding programmes since the variability created through hybridisation between the contrasting forms could be exploited.
Fusarium wilt is an important soilborne disease of pigeonpea, caused by Fusarium udum. In this st... more Fusarium wilt is an important soilborne disease of pigeonpea, caused by Fusarium udum. In this study, we have designed a real-time PCR assay for the detection of Fusarium udum from infected pigeonpea plants. Based on Topoisomerase-II gene sequence data from Fusarium udum and other related Fusarium species, a pair of primer was designed. The species-specific primers were tested in real-time PCR SYBR green assay. No increasing fluorescence signals exceeding the baseline threshold was observed with tested microbes, except Fusarium udum DNA. A single dissociation peak of increased fluorescence was obtained for the specific primers at melting temperature of 81.25°C. The real-time PCR showed a lowest detection of 0.1 pg genomic DNA. The assay was more sensitive, accurate and less time consuming for detection of Fusarium udum in infected plants root.
The molecular identification protocol for Pseudomonas introduces PCR cycle sequencing and some ba... more The molecular identification protocol for Pseudomonas introduces PCR cycle sequencing and some basic bioinformatics tools. First follow a simple protocol to isolate genomic DNA from the bacteria. This protocol involves breaking the cells open with a series of freeze/thaw cycles and then centrifuging to remove cellular debris. Many techniques exist for the identification of Pseudomonas. We present a detailed explanation for setup of 16S rRNA amplification and 16S rRNA RFLP. First after isolation of DNA a PCR reaction has to set up to amplify a region of the 16S rRNA gene. The PCR product should be cleaned up by using PCR purification kit, which cleaves excess primers and inactivates free nucleotides. The cleaned PCR product is then used as the template for a sequencing reaction. Sequencing should be done by using BigDye reagents and the reactions are run in a thermocycler (PCR machine). The completed samples are then sent to a core facility to obtain the sequence. Finally, view the electropherograms from the sequencing reaction, then use the sequence in a BLAST search limited to a bacterial data base. Students can identify their unknown bacteria by examining the top-scoring sequences from the BLAST search results. 16S rRNA-RFLP is an important tool to understand the phylogenic similarity between isolates so that one can avoid the sequencing of the isolates which are similar and it leads to the reduction of cost.
Cancer is a major cause of death worldwide, with an increasing number of cases being reported ann... more Cancer is a major cause of death worldwide, with an increasing number of cases being reported annually. The elevated rate of mortality necessitates a global challenge to explore newer sources of anticancer drugs. Recent advancements in cancer treatment involve the discovery and development of new and improved chemotherapeutics derived from natural or synthetic sources. Natural sources offer the potential of finding new structural classes with unique bioactivities for cancer therapy. Endophytic fungi represent a rich source of bioactive metabolites that can be manipulated to produce desirable novel analogs for chemotherapy. This review offers a current and integrative account of clinically used anticancer drugs such as taxol, podophyllotoxin, camptothecin, and vinca alkaloids in terms of their mechanism of action, isolation from endophytic fungi and their characterization, yield obtained, and fungal strain improvement strategies. It also covers recent literature on endophytic fungal metabolites from terrestrial, mangrove, and marine sources as potential anticancer agents and emphasizes the findings for cytotoxic bioactive compounds tested against specific cancer cell lines.
The prospective of endophytic microorganisms allied with medicinal plants is disproportionally la... more The prospective of endophytic microorganisms allied with medicinal plants is disproportionally large compared to those in other biomes. The use of antagonistic microorganisms to control devastating fungal pathogens is an attractive and eco-friendly substitute for chemical pesticides. Many species of actinomycetes, especially the genus Streptomyces, are well known as biocontrol agents. We investigated the culturable community composition and biological control ability of endophytic Streptomyces sp. associated with an ethanobotanical plant Schima wallichi. A total of 22 actinobacterial strains were isolated from different organs of selected medicinal plants and screened for their biocontrol ability against seven fungal phytopathogens. Seven isolates showed significant inhibition activity against most of the selected pathogens. Their identification based on 16S rRNA gene sequence analysis, strongly indicated that all strains belonged to the genus Strepto myces. An endophytic strain BPS...
The genus Streptomyces under phylum actinobacteria has been recognized as a prolific source for t... more The genus Streptomyces under phylum actinobacteria has been recognized as a prolific source for the production of bioactive secondary metabolites. An actinobacterial strain designated as DST103 isolated from a wetland fresh water sediment of Tamdil Lake, Mizoram, Northeast, India was identified as Streptomyces cyaneofuscatus (KY287599) using 16SrRNA gene sequencing which shares 99.87% sequence similarity with Streptomyces cyaneofuscatus NRRL B-2570 (T) . The strain showed broad spectrum antimicrobial activities against Gram negative bacteria (Escherichia coli MTCC 739 and Pseudomonas aeruginosa MTCC 2453), Gram positive bacteria (Micrococcus luteus NCIM 2170 and Staphylococcus aureus MTCC 96) and yeast pathogen Candida albicans MTCC 3017). The methanolic extract of the strain DST103 exhibited highest antimicrobial activity against E. coli (IC50 = 2.10 μg/mL) and minimum activity against S. aureus (IC50 = 43.63 μg/mL). Five antibiotics [trimethoprim (18 μg/g), fluconazole (6 μg/g), k...
Antimicrobial resistance poses a serious challenge to global public health. In this study, fifty ... more Antimicrobial resistance poses a serious challenge to global public health. In this study, fifty bacterial strains were isolated from the sediments of a freshwater lake and were screened for antibiotic resistance. Out of fifty isolates, thirty-three isolates showed resistance against at least two of the selected antibiotics. Analysis of 16S rDNA sequencing revealed that the isolates belonged to ten different genera, namely Staphylococcus(n = 8), Bacillus(n = 7), Lysinibacillus(n = 4), Achromobacter(n=3), bacterium(n = 3), Methylobacterium(n = 2), Bosea(n = 2), Aneurinibacillus(n = 2), Azospirillum(n = 1), Novosphingobium(n = 1). Enterobacterial repetitive intergenic consensus (ERIC) and BOX-PCR markers were used to study the genetic relatedness among the antibiotic resistant isolates. Further, the isolates were screened for their antimicrobial activity against bacterial pathogens viz., Staphylococcus aureus(MTCC-96), Pseudomonas aeruginosa(MTCC-2453) and Escherichia coli(MTCC-739), ...
Information on rhizosphere microbiome of endemic plants from high mountain ecosystems against tho... more Information on rhizosphere microbiome of endemic plants from high mountain ecosystems against those of cultivated plantations is inadequate. Comparative bacterial profiles of endemic medicinal plant Rhododendron arboreum Sm. subsp. delavayi rhizosphere pertaining to four altitudinal zonation Pankang Thang (PTSO), Nagula, Y-junction and Bum La (Indo-China border; in triplicates each) along cold adapted Eastern slope of Himalayan Tawang region, India is described here. Significant differences in DGGE profile between below ground bulk vs. rhizospheric community profile associated with the plant was identified. Tagged 16S amplicon sequencing from PTSO (3912 m) to Bum La (4509 m), revealed that soil pH, total nitrogen (TN), organic matter (OM) significantly influenced the underlying bacterial community structure at different altitudes. The relative abundance of Acidobacteria was inversely related to pH, as opposed to TN which was positively correlated to Acidobacteria and Proteobacteria ...
Journal of environmental biology / Academy of Environmental Biology, India, 2016
Distributions of endophytic fungi associated with ethnomedicinal plant Melastoma malabathricum L.... more Distributions of endophytic fungi associated with ethnomedicinal plant Melastoma malabathricum L. was studied and 91 isolates belonging to 18 genera were recovered. The isolates were distributed to sordariomycetes (62.63%), dothideomycetes (19.78%), eurotiomycetes (7.69%), zygomycetes (4.19%), agaricomycetes (1.09%), and mycelia sterilia (4.39%). Based on colony morphology and examination of spores, the isolates were classified into 18 taxa, of which Colletotrichum, Phomopsis and Phoma were dominant, their relative frequencies were 23.07%, 17.58% and 12.08% respectively. The colonization rate of endophytic fungi was determined and found to be significantly higher in leaf segments (50.76%), followed by root (41.53%) and stem tissues (27.69%). All the isolates were screened for antimicrobial activity and revealed that 26.37% endophytic fungi were active against one or more pathogens. Twenty four isolates showing significant antimicrobial activity were identified by sequencing the ITS1...
The perennial grasses are considered as a rich source of lignocellulosic biomass, making it a sec... more The perennial grasses are considered as a rich source of lignocellulosic biomass, making it a second generation alternative energy source and can diminish the use of fossil fuels. In this work, four perennial grasses Saccharum arundinaceum, Panicum antidotale, Thysanolaena latifolia, and Neyraudia reynaudiana were selected to verify their potential as a substrate to produce hydrolytic enzymes and to evaluate them as second generation energy biomass. Here, cellulase and hemi-cellulase producing three endophytic bacteria (Burkholderia cepacia BPS-GB3, Alcaligenes faecalis BPS-GB5 and Enterobacter hormaechei BPS-GB8) recovered from N. reynaudiana and S. arundinaceum were selected to develop a triculture (CC3) consortium. During 12 days of submerged cultivation, a 55-70% loss in dry weight was observed and the maximum activity of β-glucosidase (5.36-12.34 IU) and Xylanase (4.33 to 10.91 IU) were observed on 2nd and 6th day respectively, whereas FPase (0.26 to 0.53 IU) and CMCase (2.31 t...
The present paper deals with the electrical characterization of sputtered ZrO 2 /Si interface dep... more The present paper deals with the electrical characterization of sputtered ZrO 2 /Si interface deposited in N 2 containing plasma. Incorporation of nitrogen in the sputter deposited films was confirmed by glancing angle X-Ray diffraction measurement. MOS C-V and I-V techniques were used for interface characterization. Nitrogen incorporated ZrO 2 MOS capacitors exhibited higher breakdown voltage and lower leakage current than structures having ZrO 2 dielectric films sputtered in pure argon atmosphere. Different device parameters such as flat band voltage, leakage current, breakdown voltage, charge defects were extracted and compared with and without nitrogen incorporated ZrO 2 /Si MOS capacitor structures. The effect of post deposition annealing on the electrical behavior of ZrO 2 /Si interface was also investigated.
In the present paper, an attempt has been made to examine variations of rice production in differ... more In the present paper, an attempt has been made to examine variations of rice production in different categories of the farmers. A study on economics of rice production in Jhansi district of Uttar Pradesh was conducted for analysis the cost of inputoutput in rice production. The study covered five villages of Jhansi district and data on constraints and cost-return aspects of rice cultivation were collected from 100 farmers. The overall input-output ratio at cost A 1 /A 2 , cost B 1 , cost B 2 , cost C 1 and cost C 2 were 1:3.37, 1:2.56, 1:1.77, 1:1.96 and 1:1.46, respectively. Rice returns to scale on marginal, small, medium and large farmers characterized by decreasing return to scale. For seed, manure and fertilizers and irrigation on all the four categories of farmers, the marginal value productivities were positive and more than unity indicating further scope to increase the investment. Major constraints in rice production as perceived by the farmers were financial related problem (44%), technical related problem (40%), miscellaneous related problem (31%) and management problem (28%).
Fusarium wilt and charcoal rot diseases. The dose effect of 0.01 to 20 mM riboflavin showed that ... more Fusarium wilt and charcoal rot diseases. The dose effect of 0.01 to 20 mM riboflavin showed that 1.0 mM concentration was sufficient for maximum induction of resistance; higher concentration did not increase the effect. At this concentration, riboflavin neither caused cell death of the host plant nor directly affected the pathogen's growth. In time course observation, it was observed that riboflavin treated chickpea plants were inducing resistance 2 days after treatment and reached its maximum level from 5 to 7 days and then decreased. Riboflavin had no effect on salicylic acid (SA) levels in chickpea, however, riboflavin induced plants found accumulation of phenols and a greater activities of phenylalanine ammonia lyase (PAL) and pathogenesis related (PR) protein, peroxidase was observed in induced plant than the control. Riboflavin pre-treated plants challenged with the pathogens exhibited maximum activity of the peroxidases 4 days after treatment. Molecular weight of the purified peroxidase was 42 kDa. From these studies we demonstrated that riboflavin induced resistance is PRprotein mediated but is independent of salicylic acid.
In order to elucidate the elicitor properties of cell-wall protein (CWP) of Fusarium oxysporum f.... more In order to elucidate the elicitor properties of cell-wall protein (CWP) of Fusarium oxysporum f. sp. ciceri and Macrophomina phaseolina, CWPs were extracted and tested against chickpea. The chickpea seedlings exposed to CWPs showed enhanced synthesis of phenol, pathogenesis-related protein and activities of phenylalanine ammonia lyase and peroxidase relative to water-treated controls. Both Fusarium wilt and charcoal rot diseases of chickpea were significantly reduced in seedlings following CWP treatment. However, the same CWPs failed to antagonise the same pathogens in petri dish assays. The results suggest that CWPs of Fusarium and Macrophomina have elicitor properties and effectively induced resistance in chickpea.
Thirty isolates of Fusarium oxysporum f. sp. ciceri were isolated from rhizosphere soil of chickp... more Thirty isolates of Fusarium oxysporum f. sp. ciceri were isolated from rhizosphere soil of chickpea from different locations in Northern India. The amount of genetic variation was evaluated by polymerase chain reaction (PCR) amplification with a set of 40 RAPD primers and 2 IGS primers. Less than 10% of the amplified fragments in each case were polymorphic. Genetic similarity between each of the isolates was calculated and results indicate that there was little genetic variability among the isolates collected from the different locations. At the 0.75 similarity index the isolates divides into three groups. Isolates Foc-A18, Foc-A19, Foc-A20 forming a similar group and far different from other isolates.
Fusarium wilt caused by Fusarium oxysporum f. sp. ciceri causes considerable yield loss of chickp... more Fusarium wilt caused by Fusarium oxysporum f. sp. ciceri causes considerable yield loss of chickpea. Pseudomonas fluorescens4-92 (Pf4-92) strain can suppress the disease. Amendment of zinc EDTA and copper EDTA could not suppress the disease significantly when used alone; however, they significantly suppressed the disease in presence of Pf4-92. In vitro observation showed that at 40, 30 and 20 mg ml À1 concentrations of these minerals, i.e. Zn, Cu and Zn plus Cu, respectively, completely repressed the production of the phytotoxin, fusaric acid (FA). FA concentration (0.5 mg ml À1 ) has been shown to suppress the production of 2,4diacetylphloroglucinol (DAPG) by Pf4-92, and DAPG, salicylic acid, pyochelin and pyoluteorin production was enhanced by these mineral amendments. In rockwool bioassays, Zn, Cu and Zn plus Cu amendments reduced FA production and enhanced DAPG production. This study demonstrates that Zn and Cu enhance biocontrol activity by reducing FA produced by the pathogen, F.
In the high altitude areas of western Himalaya, barley is a crop of marginal, low input drought s... more In the high altitude areas of western Himalaya, barley is a crop of marginal, low input drought stressed environments. The landraces grown in these areas are favoured for their quality, both as grain and straw. However, area under the naked barley landraces, during the last three to four decades, has declined considerably and their ex situ and in situ conservation requires attention. Morphological and RAPD descriptors of a collection of 70 landraces from the higher Himalayan ranges of Uttaranchal state were used to analyse levels of genetic diversity. A wide range of variation was recorded for various morphological characters in univariate analysis. The multivariate analysis based on six quantitative traits distinguished accessions from different geographical areas in the region but failed to separate naked from covered barleys. Clustering based on qualitative traits, however, clearly distinguished naked and covered forms. RAPD profiles efficiently differentiated naked barleys from covered forms, but could not differentiate between oriental and occidental covered forms. A set of 11 predominant landraces were subjected to detailed population genetic analysis. More diversity was observed in covered barleys than the naked forms, both for morphological and RAPD markers. The low diversity in naked barley populations was attributed to either genetic drift or to a founder effect, while the high diversity in covered barley populations was attributed to their large-scale cultivation for animal feed and brewing purposes. Allelic combinations were not randomly distributed, as a geographic trend was closely related to covered and naked barleys. Since naked barleys are poorly represented in the national collections, a systematic collection from the entire region is suggested. The genetic differences between covered and naked barleys may be relevant to breeding programmes since the variability created through hybridisation between the contrasting forms could be exploited.
Fusarium wilt is an important soilborne disease of pigeonpea, caused by Fusarium udum. In this st... more Fusarium wilt is an important soilborne disease of pigeonpea, caused by Fusarium udum. In this study, we have designed a real-time PCR assay for the detection of Fusarium udum from infected pigeonpea plants. Based on Topoisomerase-II gene sequence data from Fusarium udum and other related Fusarium species, a pair of primer was designed. The species-specific primers were tested in real-time PCR SYBR green assay. No increasing fluorescence signals exceeding the baseline threshold was observed with tested microbes, except Fusarium udum DNA. A single dissociation peak of increased fluorescence was obtained for the specific primers at melting temperature of 81.25°C. The real-time PCR showed a lowest detection of 0.1 pg genomic DNA. The assay was more sensitive, accurate and less time consuming for detection of Fusarium udum in infected plants root.
The molecular identification protocol for Pseudomonas introduces PCR cycle sequencing and some ba... more The molecular identification protocol for Pseudomonas introduces PCR cycle sequencing and some basic bioinformatics tools. First follow a simple protocol to isolate genomic DNA from the bacteria. This protocol involves breaking the cells open with a series of freeze/thaw cycles and then centrifuging to remove cellular debris. Many techniques exist for the identification of Pseudomonas. We present a detailed explanation for setup of 16S rRNA amplification and 16S rRNA RFLP. First after isolation of DNA a PCR reaction has to set up to amplify a region of the 16S rRNA gene. The PCR product should be cleaned up by using PCR purification kit, which cleaves excess primers and inactivates free nucleotides. The cleaned PCR product is then used as the template for a sequencing reaction. Sequencing should be done by using BigDye reagents and the reactions are run in a thermocycler (PCR machine). The completed samples are then sent to a core facility to obtain the sequence. Finally, view the electropherograms from the sequencing reaction, then use the sequence in a BLAST search limited to a bacterial data base. Students can identify their unknown bacteria by examining the top-scoring sequences from the BLAST search results. 16S rRNA-RFLP is an important tool to understand the phylogenic similarity between isolates so that one can avoid the sequencing of the isolates which are similar and it leads to the reduction of cost.
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Papers by Bhim P Singh