Diseases caused by begomoviruses (family Geminiviridae, genus Begomovirus) constitute a serious c... more Diseases caused by begomoviruses (family Geminiviridae, genus Begomovirus) constitute a serious constraint to tropical and sub-tropical agro-ecosystems worldwide. Begomoviral diseases can reduce yields to zero in extreme cases, leading to catastrophic losses in agriculture. These diseases continue to evolve and pose a serious threat to sustainable agriculture throughout the world, particularly in the tropics and sub-tropics. The rapid emergence of begomoviral epidemics might be occurring in connection with some factors like evolution of new virus variants, the appearance of efficient vectors, changes in cropping systems, introduction of susceptible plant varieties, and changes in climatic conditions. Another concern is the emergence of a begomovirus complex and satellite DNA molecules. Weeds are the major reservoir of begomoviruses for crops as they provide shelter to the virus and their insect-vectors during cropping and off-season. Weeds, as host of many begomoviruses, are known across the world, but a limited number of studies have been conducted on the role of weed hosts in causing wide-spread epidemics of begomoviral diseases in crop plants. Ageratum conyzoides is a global weed, found widely and frequently occurring in south Asia, and is very difficult to control. It has been reported to be the reservoir of many economic diseases caused by begomoviruses in tropical and subtropical parts of the world. Recently, Ageratum enation virus has quickly spread to many economically important crops and is posing a serious threat to agriculture in India. The variants/ strains of the virus are evolving very fast and are becoming the major limiting factor to agro-eco systems particularly in the northern part of the country. So far, 33 isolates originating from different plant species (including ornamentals, vegetables, legumes, and weeds) have been reported from India and the neighboring countries of Pakistan and Nepal.
Leaf curl disease symptoms were observed in tomato crop grown in a tomato field at Matera distric... more Leaf curl disease symptoms were observed in tomato crop grown in a tomato field at Matera district of Bahraich, India, in March 2013 with an 85% disease incidence. The infected plants exhibited leaf curl symptoms accompanied with puckering, vein swelling and stunting of the whole plant. PCR carried out with begomovirus coat protein gene and DNA betaspecific primer sets resulted in positive amplification of~775 bp and 1.35 kbp, respectively, with all symptom-bearing plant samples. BLASTn and phylogenetic analyses of CP gene sequences showed highest and close relationship with Croton yellow vein mosaic virus (CYVMV) isolates, while the phylogenetic study of betasatellite sequence showed distinct relationships with other begomovirus associated betasatellites reported from India and abroad. This is a first report of a CYVMV associated with tomato leaf curl disease in India.
Two new compounds catharanthusopimaranoside A (1) and catharanthusopimaranoside B (2) along with ... more Two new compounds catharanthusopimaranoside A (1) and catharanthusopimaranoside B (2) along with three known compounds have been isolated from the hairy root cultures of Catharanthus roseus. Their structures have been elucidated with the help of 500 MHz NMR using 1D and 2D spectral methods viz: NMR, 1H-1H COSY, 1H-13C HETCOR, etc., and DEPT aided by EIMS, FABMS, and IR spectroscopy.
ABSTRACT Three new compounds, 4-hydroxymethylene-7-(9,9,13-trimethylcyclohexyl)-heptanyl-3′,7′,7′... more ABSTRACT Three new compounds, 4-hydroxymethylene-7-(9,9,13-trimethylcyclohexyl)-heptanyl-3′,7′,7′-trimethylcyclohexa-2′,4′-dien-1′-oate (1), 1-(n-hexadec-7-enoxy)-6-(n-octadecanoxy)-β-D-glucopyranoside (2), and (Z)-12-hydroxy-9-octadecenoic acid-12-β-D-glucopyranoside (3), along with the known compound hexacosanoic acid (4), were isolated and identified from the rice hulls of Oryza sativa. Their structures were elucidated by 1D and 2D NMR spectroscopic techniques (1H-1H COSY, 1H-13C HETCOR, DEPT) aided by EIMS, FABMS, HRFABMS, and IR spectra.
Potato (Solanum tuberosum L.) is a widely cultivated and commercially important vegetable crop in... more Potato (Solanum tuberosum L.) is a widely cultivated and commercially important vegetable crop in India where it is cultivated in an area of about 1.34 million ha with a total production of about 24.7 million tons. Phytoplasma diseases of potato have been reported from several parts of the world as associated with organisms belonging to different 16Sr DNA group/subgroups. In December, 2011, little leaf disease symptoms were observed in potato crops grown in the Kushinagar district of Uttar Pradesh (India). Phytoplasmas were detected by PCR using P1/P7 primers (Deng and Hiruki, 1991; Schneider et al., 1995) which yilded amplicons ca. 1.8 kb in size only from four symptomatic samples. All four amplicons were directly sequenced from both ends and the sequence was deposited in GenBank under the accession No. KC312703. The little leaf potato phytoplasma isolate shared high 16S rDNA sequence identity (99%) with several isolates of Candidatus Phytoplasma asteris (16SrI group) from differen...
Onion extract structural changes during in vitro digestion and its potential antioxidant effect o... more Onion extract structural changes during in vitro digestion and its potential antioxidant effect on brain lipids obtained from low- and high-fat-fed mice
Phytoplasmas are cell wall-lacking mollicutes found associated with plant diseases in a wide rang... more Phytoplasmas are cell wall-lacking mollicutes found associated with plant diseases in a wide range of plant species ranging from grasses to trees (Al-Saady & Khan, 2006). Ageratum conyzoides (family Asteraceae ) commonly known as goat…
Bacteria were completely eliminated from rice seeds following immersion in household bleach solut... more Bacteria were completely eliminated from rice seeds following immersion in household bleach solutions (50% bleach and 2.6% NaOCl) adjusted to pH 7.0 in 0.5 M potassium phosphate, while fungi were eliminated at pH 5.0 and below. Mercuric chloride was used to disinfest non-dormant rice seeds in order to test the direct effect of sodium hypochlorite on rice seedling growth apart from an indirect effect related to elimination of microbial contaminants. Seeds were immersed for 2 h in each solution or water in each of the following treatments: (i) sterilewater followed by sterile water, (ii) HgCl2 (1,000 μg/ml) followed by sterile water, (iii) HgCl2 followed by KH2PO4 (0.3 M), (iv) HgCl2 followed by NaOCl, and (v) NaOCl followed by sterile water. Sodium hypochlorite solutions were prepared in 0.3 M potassium phosphate, which gave a final pH of 7.3. Seedling growth in treatments in which seeds were treated with HgCl2 followed by NaOCl, and NaOCl followed by sterile water, was significantly...
Seedling disease, caused primarily by several species of Pythium, is one of the major constraints... more Seedling disease, caused primarily by several species of Pythium, is one of the major constraints to water-seeded rice production in Louisiana. The disease, also known as water-mold disease, seed rot, and seedling damping-off, causes stand reductions and growth abnormalities. In severe cases, fields must be replanted, which may result in delayed harvests and reduced yields. To develop more effective disease management tactics including biological control, this study was conducted primarily to determine sites of infection in seeds and seedlings; effect of plant age on susceptibility to P. arrhenomanes, P. myriotylum, and P. dissotocum; and minimum exposure times required for infection and seedling death. In addition, the effect of water depth on seedling disease was investigated. Infection rates of seed embryos were significantly higher than those of endosperms for all three Pythium spp. The development of roots from dry-seeded seedlings was significantly reduced by P. arrhenomanes a...
Experiments were conducted to screen 23 known allelochemicals, including sinapic acid, and an equ... more Experiments were conducted to screen 23 known allelochemicals, including sinapic acid, and an equimolar mixture of the chemicals for potential allelopathy on barnyardgrass (Echinochloa crus-galli var. oryzicola), and to identify allelochemical(s) from hull extracts from three rice (Oryza sativa L.) cultivars. In a bioassay, the inhibitory effect was increased as the concentration of allelochemicals increased from 10 À5 to 10 À3 M. Ferulic, p-hydroxybenzoic, p-coumaric, and m-coumaric acids were the most active compounds and caused the greatest effect on seed germination, germination rate, and total seedling dry weight reduction. phydroxybenzoic acid (10 À3 M; pH 4.1) showed the greatest inhibitory effect on the same parameters. HPLC analysis using three rice cultivars, Janganbyeo, Baekambyeo, and Labelle, showed that the concentration and composition of potentially allelopathic compounds depended upon the cultivar. Hull extracts from the allelopathic cultivar Janganbyeo contained higher levels of phydroxybenzoic acid than did those of the non-allelopathic cultivars Labelle and Baekambyeo. Nine compounds, including phydroxybenzoic acid (4.29 mg/g) in Janganbyeo, seven compounds including m-coumaric (0.43 mg/g) in Labelle, and five compounds including p-hydroxybenzoic acid (0.36 mg/g) in Baekambyeo, were detected. Preliminary identification by HPLC analysis resulted in peaks with retention times near those of standards, including p-hydroxybenzoic acid that was confirmed with EI/ MS. It is suggested that these compounds may be, at least, a key factor in rice allelopathy on barnyardgrass, and the information presented may contribute to the development of naturally occurring herbicides.
Diseases caused by begomoviruses (family Geminiviridae, genus Begomovirus) constitute a serious c... more Diseases caused by begomoviruses (family Geminiviridae, genus Begomovirus) constitute a serious constraint to tropical and sub-tropical agro-ecosystems worldwide. Begomoviral diseases can reduce yields to zero in extreme cases, leading to catastrophic losses in agriculture. These diseases continue to evolve and pose a serious threat to sustainable agriculture throughout the world, particularly in the tropics and sub-tropics. The rapid emergence of begomoviral epidemics might be occurring in connection with some factors like evolution of new virus variants, the appearance of efficient vectors, changes in cropping systems, introduction of susceptible plant varieties, and changes in climatic conditions. Another concern is the emergence of a begomovirus complex and satellite DNA molecules. Weeds are the major reservoir of begomoviruses for crops as they provide shelter to the virus and their insect-vectors during cropping and off-season. Weeds, as host of many begomoviruses, are known across the world, but a limited number of studies have been conducted on the role of weed hosts in causing wide-spread epidemics of begomoviral diseases in crop plants. Ageratum conyzoides is a global weed, found widely and frequently occurring in south Asia, and is very difficult to control. It has been reported to be the reservoir of many economic diseases caused by begomoviruses in tropical and subtropical parts of the world. Recently, Ageratum enation virus has quickly spread to many economically important crops and is posing a serious threat to agriculture in India. The variants/ strains of the virus are evolving very fast and are becoming the major limiting factor to agro-eco systems particularly in the northern part of the country. So far, 33 isolates originating from different plant species (including ornamentals, vegetables, legumes, and weeds) have been reported from India and the neighboring countries of Pakistan and Nepal.
Leaf curl disease symptoms were observed in tomato crop grown in a tomato field at Matera distric... more Leaf curl disease symptoms were observed in tomato crop grown in a tomato field at Matera district of Bahraich, India, in March 2013 with an 85% disease incidence. The infected plants exhibited leaf curl symptoms accompanied with puckering, vein swelling and stunting of the whole plant. PCR carried out with begomovirus coat protein gene and DNA betaspecific primer sets resulted in positive amplification of~775 bp and 1.35 kbp, respectively, with all symptom-bearing plant samples. BLASTn and phylogenetic analyses of CP gene sequences showed highest and close relationship with Croton yellow vein mosaic virus (CYVMV) isolates, while the phylogenetic study of betasatellite sequence showed distinct relationships with other begomovirus associated betasatellites reported from India and abroad. This is a first report of a CYVMV associated with tomato leaf curl disease in India.
Two new compounds catharanthusopimaranoside A (1) and catharanthusopimaranoside B (2) along with ... more Two new compounds catharanthusopimaranoside A (1) and catharanthusopimaranoside B (2) along with three known compounds have been isolated from the hairy root cultures of Catharanthus roseus. Their structures have been elucidated with the help of 500 MHz NMR using 1D and 2D spectral methods viz: NMR, 1H-1H COSY, 1H-13C HETCOR, etc., and DEPT aided by EIMS, FABMS, and IR spectroscopy.
ABSTRACT Three new compounds, 4-hydroxymethylene-7-(9,9,13-trimethylcyclohexyl)-heptanyl-3′,7′,7′... more ABSTRACT Three new compounds, 4-hydroxymethylene-7-(9,9,13-trimethylcyclohexyl)-heptanyl-3′,7′,7′-trimethylcyclohexa-2′,4′-dien-1′-oate (1), 1-(n-hexadec-7-enoxy)-6-(n-octadecanoxy)-β-D-glucopyranoside (2), and (Z)-12-hydroxy-9-octadecenoic acid-12-β-D-glucopyranoside (3), along with the known compound hexacosanoic acid (4), were isolated and identified from the rice hulls of Oryza sativa. Their structures were elucidated by 1D and 2D NMR spectroscopic techniques (1H-1H COSY, 1H-13C HETCOR, DEPT) aided by EIMS, FABMS, HRFABMS, and IR spectra.
Potato (Solanum tuberosum L.) is a widely cultivated and commercially important vegetable crop in... more Potato (Solanum tuberosum L.) is a widely cultivated and commercially important vegetable crop in India where it is cultivated in an area of about 1.34 million ha with a total production of about 24.7 million tons. Phytoplasma diseases of potato have been reported from several parts of the world as associated with organisms belonging to different 16Sr DNA group/subgroups. In December, 2011, little leaf disease symptoms were observed in potato crops grown in the Kushinagar district of Uttar Pradesh (India). Phytoplasmas were detected by PCR using P1/P7 primers (Deng and Hiruki, 1991; Schneider et al., 1995) which yilded amplicons ca. 1.8 kb in size only from four symptomatic samples. All four amplicons were directly sequenced from both ends and the sequence was deposited in GenBank under the accession No. KC312703. The little leaf potato phytoplasma isolate shared high 16S rDNA sequence identity (99%) with several isolates of Candidatus Phytoplasma asteris (16SrI group) from differen...
Onion extract structural changes during in vitro digestion and its potential antioxidant effect o... more Onion extract structural changes during in vitro digestion and its potential antioxidant effect on brain lipids obtained from low- and high-fat-fed mice
Phytoplasmas are cell wall-lacking mollicutes found associated with plant diseases in a wide rang... more Phytoplasmas are cell wall-lacking mollicutes found associated with plant diseases in a wide range of plant species ranging from grasses to trees (Al-Saady & Khan, 2006). Ageratum conyzoides (family Asteraceae ) commonly known as goat…
Bacteria were completely eliminated from rice seeds following immersion in household bleach solut... more Bacteria were completely eliminated from rice seeds following immersion in household bleach solutions (50% bleach and 2.6% NaOCl) adjusted to pH 7.0 in 0.5 M potassium phosphate, while fungi were eliminated at pH 5.0 and below. Mercuric chloride was used to disinfest non-dormant rice seeds in order to test the direct effect of sodium hypochlorite on rice seedling growth apart from an indirect effect related to elimination of microbial contaminants. Seeds were immersed for 2 h in each solution or water in each of the following treatments: (i) sterilewater followed by sterile water, (ii) HgCl2 (1,000 μg/ml) followed by sterile water, (iii) HgCl2 followed by KH2PO4 (0.3 M), (iv) HgCl2 followed by NaOCl, and (v) NaOCl followed by sterile water. Sodium hypochlorite solutions were prepared in 0.3 M potassium phosphate, which gave a final pH of 7.3. Seedling growth in treatments in which seeds were treated with HgCl2 followed by NaOCl, and NaOCl followed by sterile water, was significantly...
Seedling disease, caused primarily by several species of Pythium, is one of the major constraints... more Seedling disease, caused primarily by several species of Pythium, is one of the major constraints to water-seeded rice production in Louisiana. The disease, also known as water-mold disease, seed rot, and seedling damping-off, causes stand reductions and growth abnormalities. In severe cases, fields must be replanted, which may result in delayed harvests and reduced yields. To develop more effective disease management tactics including biological control, this study was conducted primarily to determine sites of infection in seeds and seedlings; effect of plant age on susceptibility to P. arrhenomanes, P. myriotylum, and P. dissotocum; and minimum exposure times required for infection and seedling death. In addition, the effect of water depth on seedling disease was investigated. Infection rates of seed embryos were significantly higher than those of endosperms for all three Pythium spp. The development of roots from dry-seeded seedlings was significantly reduced by P. arrhenomanes a...
Experiments were conducted to screen 23 known allelochemicals, including sinapic acid, and an equ... more Experiments were conducted to screen 23 known allelochemicals, including sinapic acid, and an equimolar mixture of the chemicals for potential allelopathy on barnyardgrass (Echinochloa crus-galli var. oryzicola), and to identify allelochemical(s) from hull extracts from three rice (Oryza sativa L.) cultivars. In a bioassay, the inhibitory effect was increased as the concentration of allelochemicals increased from 10 À5 to 10 À3 M. Ferulic, p-hydroxybenzoic, p-coumaric, and m-coumaric acids were the most active compounds and caused the greatest effect on seed germination, germination rate, and total seedling dry weight reduction. phydroxybenzoic acid (10 À3 M; pH 4.1) showed the greatest inhibitory effect on the same parameters. HPLC analysis using three rice cultivars, Janganbyeo, Baekambyeo, and Labelle, showed that the concentration and composition of potentially allelopathic compounds depended upon the cultivar. Hull extracts from the allelopathic cultivar Janganbyeo contained higher levels of phydroxybenzoic acid than did those of the non-allelopathic cultivars Labelle and Baekambyeo. Nine compounds, including phydroxybenzoic acid (4.29 mg/g) in Janganbyeo, seven compounds including m-coumaric (0.43 mg/g) in Labelle, and five compounds including p-hydroxybenzoic acid (0.36 mg/g) in Baekambyeo, were detected. Preliminary identification by HPLC analysis resulted in peaks with retention times near those of standards, including p-hydroxybenzoic acid that was confirmed with EI/ MS. It is suggested that these compounds may be, at least, a key factor in rice allelopathy on barnyardgrass, and the information presented may contribute to the development of naturally occurring herbicides.
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