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Peter J Lockhart - One of the best experts on this subject based on the ideXlab platform.
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identification of chloroplast genome loci suitable for high resolution phylogeographic studies of Colocasia esculenta l schott araceae and closely related taxa
Molecular Ecology Resources, 2013Co-Authors: Ibrar Ahmed, Peter J Matthews, Patrick J Biggs, Muhammad Naeem, Patricia A Mclenachan, Peter J LockhartAbstract:Recently, we reported the chloroplast genome-wide association of oligonucleotide repeats, indels and nucleotide substitutions in aroid chloroplast genomes. We hypothesized that the distribution of oligonucleotide repeat sequences in a single representative genome can be used to identify mutational hotspots and loci suitable for population genetic, phylogenetic and phylogeographic studies. Using information on the location of oligonucleotide repeats in the chloroplast genome of taro (Colocasia esculenta), we designed 30 primer pairs to amplify and sequence polymorphic loci. The primers have been tested in a range of intra-specific to intergeneric comparisons, including ten taro samples (Colocasia esculenta) from diverse geographical locations, four other Colocasia species (C. affinis, C. fallax, C. formosana, C. gigantea) and three other aroid genera (represented by Remusatia vivipara, Alocasia brisbanensis and Amorphophallus konjac). Multiple sequence alignments for the intra-specific comparison revealed nucleotide substitutions (point mutations) at all 30 loci and microsatellite polymorphisms at 14 loci. The primer pairs reported here reveal levels of genetic variation suitable for high-resolution phylogeographic and evolutionary studies of taro and other closely related aroids. Our results confirm that information on repeat distribution can be used to identify loci suitable for such studies, and we expect that this approach can be used in other plant groups.
Ibrar Ahmed - One of the best experts on this subject based on the ideXlab platform.
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identification of chloroplast genome loci suitable for high resolution phylogeographic studies of Colocasia esculenta l schott araceae and closely related taxa
Molecular Ecology Resources, 2013Co-Authors: Ibrar Ahmed, Peter J Matthews, Patrick J Biggs, Muhammad Naeem, Patricia A Mclenachan, Peter J LockhartAbstract:Recently, we reported the chloroplast genome-wide association of oligonucleotide repeats, indels and nucleotide substitutions in aroid chloroplast genomes. We hypothesized that the distribution of oligonucleotide repeat sequences in a single representative genome can be used to identify mutational hotspots and loci suitable for population genetic, phylogenetic and phylogeographic studies. Using information on the location of oligonucleotide repeats in the chloroplast genome of taro (Colocasia esculenta), we designed 30 primer pairs to amplify and sequence polymorphic loci. The primers have been tested in a range of intra-specific to intergeneric comparisons, including ten taro samples (Colocasia esculenta) from diverse geographical locations, four other Colocasia species (C. affinis, C. fallax, C. formosana, C. gigantea) and three other aroid genera (represented by Remusatia vivipara, Alocasia brisbanensis and Amorphophallus konjac). Multiple sequence alignments for the intra-specific comparison revealed nucleotide substitutions (point mutations) at all 30 loci and microsatellite polymorphisms at 14 loci. The primer pairs reported here reveal levels of genetic variation suitable for high-resolution phylogeographic and evolutionary studies of taro and other closely related aroids. Our results confirm that information on repeat distribution can be used to identify loci suitable for such studies, and we expect that this approach can be used in other plant groups.
Ranajit Bandyopadhyay - One of the best experts on this subject based on the ideXlab platform.
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first report of leaf blight of taro Colocasia esculenta caused by phytophthora Colocasiae in ghana
Plant Disease, 2012Co-Authors: E Omane, Kamal Sharma, Lava P Kumar, K A Oduro, Eric Cornelius, I Y Opoku, A Y Akrofi, Ranajit BandyopadhyayAbstract:Taro (Colocasia esculenta (L.) Schott) is an important food crop cultivated for its edible tubers in Ghana. In May 2009, outbreaks of a destructive leaf disease were observed on several taro farms in the Atiwa, East-Akim, Fanteakwa, West-Akim, and New Juaben districts of the Eastern Region of Ghana. Symptoms began on leaves as small, brown, water-soaked lesions that enlarged and coalesced into large lesions with yellow exudate, ultimately leading to the defoliation and death of plants. Symptoms were suggestive of taro leaf blight (TLB) caused by Phytophthora Colocasiae Raciborski (3). By August 2010, the disease had spread to other taro-growing regions in Ghana. To identify the pathogen, leaf tissue from lesion margins were excised and plated on carrot agar and V8 selective media for Phytophthora and incubated at 27°C for 5 days (2). Growth from diseased tissue was used for morphological characterization. Sporangia were ovoid, hyaline, papillate, caducous, 30 to 60 × 17 to 28 μm, and pedicels were 3.5 to ...
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first report of taro Colocasia esculenta leaf blight caused by phytophthora Colocasiae in nigeria
Plant Disease, 2011Co-Authors: Ranajit Bandyopadhyay, Kamal Sharma, T J Onyeka, A Aregbesola, Lava P KumarAbstract:In November 2009, many farmers in Abia State were alarmed by complete destruction of their taro (Colocasia esculenta (L.) Schott.) crop. Symptoms, suggestive of leaf blight caused by Phytophthora Colocasiae Raciborski (2), began as small, brown, water-soaked lesions that rapidly enlarged to form large, dark brown, coalescing lesions, sometimes with orange host exudations. White sporulation was evident on the lesion surface under wet conditions. The pathogen caused rapid defoliation and killed plants. The epidemic was widespread in 2010 during the rainy season (April to November) in all taro-growing areas of Nigeria. Diseased leaves were collected from taro in Iwo Village near Ibadan, cut into 4-cm2 pieces, washed in several changes of sterile water, and incubated in petri dishes lined with wet filter paper at 22°C. Newly produced sporangia were collected from the incubated leaves and plated on a selective medium (1). Sporangia were hyaline, papillate, and measured 25 to 55 × 15 to 30 μm. Zoospores encyste...
Samuel Sefadedeh - One of the best experts on this subject based on the ideXlab platform.
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chemical composition and the effect of processing on oxalate content of cocoyam xanthosoma sagittifolium and Colocasia esculenta cormels
Food Chemistry, 2004Co-Authors: Samuel Sefadedeh, Emmanuel Kofi AgyirsackeyAbstract:Abstract The chemical composition as well as the effect of processing on the cormels of two Xanthosoma sagittifolium species and Colocasia esculenta cormels were evaluated. A 3×3 factorial experimental design with cocoyam varieties [ Xanthosoma (white-flesh), Xanthosoma (red-flesh) and Colocasia ] and cormel section (distal, middle and apical) was performed to determine the chemical composition of the cormels. Oxalate contents of the various cormels were also evaluated and the effect of processing assessed using standard analytical methods. The mean values of the proximate composition of the three cocoyam species evaluated were; crude protein 2.98–5.50 g/100 g, total fat 0.28–0.97 g/100 g, ash 1.56–2.98 g/100 g, starch 12.2–36.0 g/100 g and crude fibre 1.11–3.00 g/100 g. The results showed that the different sections of the cocoyam cormels studied were significantly different ( P ⩽0.05) in chemical composition. The apical section of all the species had high protein content while the distal section had high levels of ash, fibre and minerals. Potassium was the most abundant mineral (763–1451 μg/100 g) with appreciable amounts noted for zinc (17–51.1 μg/100 g), magnesium (46.7–85.0 μg/100 g) and phosphorus (41.6–63.1 μg/100 g). Oxalate compositions of the fresh samples were in the range of 254–381 μg/100 g for the X. sagittifolium (red-flesh), 302–323 μg/100 g for the X. sagittifolium (white-flesh) and 328–460 μg/100 g for the Colocasia esculenta. No significant differences (P⩽0.05) were found between the oven-dried and solar-dried samples. However, drum drying reduced the oxalate levels by approximately 50% to average levels ranging from 99.9 to 191 μg/100 g.
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starch structure and some properties of cocoyam xanthosoma sagittifolium and Colocasia esculenta starch and raphides
Food Chemistry, 2002Co-Authors: Samuel Sefadedeh, Emmanuel Kofiagyir SackeyAbstract:Abstract Studies were conducted on the structure and rheological properties of three cocoyam varieties [Xanthosoma sagittifolium (red-flesh), Xanthosonia sagittifolium (white-flesh) and Colocasia esculenta] starches and raphides in an attempt to characterize them. The microstructures of starch granules and raphide sizes, which were obtained from the distal, middle and apical sections of the raw cocoyam samples, were examined using a light microscope. Evaluations of the rheological properties of the cocoyam species were also conducted, using a Brabender viscoamylograph. No distinct variation was observed in starch granule sizes of the two Xanthosoma species. Starch granules sizes in the ranges of 0.74–1.19 and 0.74–1.10 μm were obtained for the Xanthosoma species (red-flesh) and Xanthosoma species (white-flesh), respectively. Significantly smaller sizes (0.05–0.08 μm) of starch granules were observed for Colocasia esculenta. Microstructures of raphide sizes which were obtained from the distal section of the cocoyam species showed significant differences (P⩽0.05) among the varieties, with the Colocasia species having more pronounced needle-like structures. Evaluation of the rheological properties of the cocoyam flours, using the Brabender viscoamylograph, showed considerable variations among the varieties, especially between the Xanthosoma species and the Colocasia species. The C. esculenta showed lower hot paste viscosity but higher thermal stability than the Xanthosoma species. Peak viscosity was highest in the X. sagittifolium (red-flesh) variety while the white-flesh variety showed the least tendency to retrogradation.
Lava P Kumar - One of the best experts on this subject based on the ideXlab platform.
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first report of leaf blight of taro Colocasia esculenta caused by phytophthora Colocasiae in ghana
Plant Disease, 2012Co-Authors: E Omane, Kamal Sharma, Lava P Kumar, K A Oduro, Eric Cornelius, I Y Opoku, A Y Akrofi, Ranajit BandyopadhyayAbstract:Taro (Colocasia esculenta (L.) Schott) is an important food crop cultivated for its edible tubers in Ghana. In May 2009, outbreaks of a destructive leaf disease were observed on several taro farms in the Atiwa, East-Akim, Fanteakwa, West-Akim, and New Juaben districts of the Eastern Region of Ghana. Symptoms began on leaves as small, brown, water-soaked lesions that enlarged and coalesced into large lesions with yellow exudate, ultimately leading to the defoliation and death of plants. Symptoms were suggestive of taro leaf blight (TLB) caused by Phytophthora Colocasiae Raciborski (3). By August 2010, the disease had spread to other taro-growing regions in Ghana. To identify the pathogen, leaf tissue from lesion margins were excised and plated on carrot agar and V8 selective media for Phytophthora and incubated at 27°C for 5 days (2). Growth from diseased tissue was used for morphological characterization. Sporangia were ovoid, hyaline, papillate, caducous, 30 to 60 × 17 to 28 μm, and pedicels were 3.5 to ...
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first report of taro Colocasia esculenta leaf blight caused by phytophthora Colocasiae in nigeria
Plant Disease, 2011Co-Authors: Ranajit Bandyopadhyay, Kamal Sharma, T J Onyeka, A Aregbesola, Lava P KumarAbstract:In November 2009, many farmers in Abia State were alarmed by complete destruction of their taro (Colocasia esculenta (L.) Schott.) crop. Symptoms, suggestive of leaf blight caused by Phytophthora Colocasiae Raciborski (2), began as small, brown, water-soaked lesions that rapidly enlarged to form large, dark brown, coalescing lesions, sometimes with orange host exudations. White sporulation was evident on the lesion surface under wet conditions. The pathogen caused rapid defoliation and killed plants. The epidemic was widespread in 2010 during the rainy season (April to November) in all taro-growing areas of Nigeria. Diseased leaves were collected from taro in Iwo Village near Ibadan, cut into 4-cm2 pieces, washed in several changes of sterile water, and incubated in petri dishes lined with wet filter paper at 22°C. Newly produced sporangia were collected from the incubated leaves and plated on a selective medium (1). Sporangia were hyaline, papillate, and measured 25 to 55 × 15 to 30 μm. Zoospores encyste...