Genetic Resources Center

Ibadan, Nigeria

Genetic Resources Center

Ibadan, Nigeria
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Dumet D.,Genetic Resources Center | Diebiru E.,Genetic Resources Center | Adeyemi A.,Genetic Resources Center | Akinyemi O.,Genetic Resources Center | And 2 more authors.
Cryo-Letters | Year: 2013

Cryopreservation via droplet vitrification showed high efficiency for cassava meristems (79% average recovery) when these were excised from in vitro seedlings. The efficiency of the process dropped considerably (to >23%) when meristems were excised from field-grown plants, thus precluding the use of such expiants for routine cryobanking. In yam, large disparities were observed in the ability of meristems to produce a shoot after cryopreservation ranging from 0 to 60%, depending on the accession. Overall, better recovery was observed for Dioscorea rotundata than for D. alata, the two main species tested. Using a probabilistic decision support tool and taking into consideration our cryoprocessing capacity, we conclude that processing 100 meristems per accession and retrieving 30 to estimate the recovery rate of the batch are a good compromise for the cryobanking routine. © Cryo Letters.


Nakamura M.,Japan National Institute of Agrobiological Science | Nakamura M.,Genetic Resources Center | Hattori M.,Japan National Institute of Agrobiological Science
Applied Entomology and Zoology | Year: 2013

The green rice leafhopper, Nephotettix cincticeps (Uhler), is an insect pest of rice and discharges β-glucosidase (EC 3.2.1.21) from its salivary glands during feeding. To investigate the biological function of this enzyme, we purified it from the heads of 18,000 adult females by acetone precipitation and a series of chromatography steps: gel filtration, cation-exchange chromatography, metal-affinity chromatography and hydrophobic interaction chromatography. During cation-exchange chromatography, β-glucosidases were eluted in three peaks (isozymes). These β-glucosidases were monomeric proteins of 58 kDa as estimated by SDS-PAGE and 62 kDa based on gel filtration. All of the purified β-glucosidase isozymes exhibited maximum activity for p-nitrophenyl β-glucoside (NPGlc) and p-nitrophenyl β-galactopyranoside (NPGal) at pH 5.5 and 5.0, respectively. There was no significant difference in substrate specificity among the three isozymes. The Km values were estimated to be 0.13 μM for NPGlc and 0.9 μM for NPGal. Among the oligosaccharide substrates examined, laminaribiose (Glc β1-3 Glc) was the most extensively hydrolyzed, sophorose (Glc β1-2 Glc) and cellobiose (Glc β1-4 Glc) were comparatively well hydrolyzed, and gentiobiose (Glc β1-6 Glc), lactose (Gal β1-4 Glc), laminaritriose, cellotriose and cellotetraose were poorly hydrolyzed. Among the glycoside substrates examined, salicin was considerably well hydrolyzed. β-Glucosidase was detected in the salivary sheaths by activity staining with a fluorescent substrate. The salivary β-glucosidase of N. cincticeps may be involved in the hydrolysis of a phenol glucoside present in the saliva, which is a step in the solidification of gelling saliva to form salivary sheaths. © 2013 The Japanese Society of Applied Entomology and Zoology.


Iseki K.,Japan International Research Center for Agricultural science | Takahashi Y.,Genetic Resources Center | Muto C.,Genetic Resources Center | Naito K.,Genetic Resources Center | Tomooka N.,Genetic Resources Center
PLoS ONE | Year: 2016

Breeding salt tolerant plants is difficult without utilizing a diversity of wild crop relatives. Since the genus Vigna (family Fabaceae) is comprised of many wild relatives adapted to various environmental conditions, we evaluated the salt tolerance of 69 accessions of this genus, including that of wild and domesticated accessions originating from Asia, Africa, Oceania, and South America. We grew plants under 50 mM and 200 mM NaCl for two weeks and then measured the biomass, relative quantum yield of photosystem II, leaf Na+ concentrations, and leaf K+ concentrations. The accessions were clustered into four groups: the most tolerant, tolerant, moderately susceptible, and susceptible. From the most tolerant group, we selected six accessions, all of which were wild accessions adapted to coastal environments, as promising sources of salt tolerance because of their consistently high relative shoot biomass and relative quantum yield. Interestingly, variations in leaf Na+ concentration were observed between the accessions in the most tolerant group, suggesting different mechanisms were responsible for their salt tolerance. Phylogenetic analysis with nuclear DNA sequences revealed that salt tolerance had evolved independently at least four times in the genus Vigna, within a relatively short period. The findings suggested that simple genetic changes in a few genes might have greatly affected salt tolerances. The elucidation of genetic mechanisms of salt tolerances in the selected accessions may contribute to improving the poor salt tolerance in legume crops. © 2016 Iseki et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.


PubMed | Genetic Resources Center and Japan International Research Center for Agricultural science
Type: Journal Article | Journal: PloS one | Year: 2016

Breeding salt tolerant plants is difficult without utilizing a diversity of wild crop relatives. Since the genus Vigna (family Fabaceae) is comprised of many wild relatives adapted to various environmental conditions, we evaluated the salt tolerance of 69 accessions of this genus, including that of wild and domesticated accessions originating from Asia, Africa, Oceania, and South America. We grew plants under 50 mM and 200 mM NaCl for two weeks and then measured the biomass, relative quantum yield of photosystem II, leaf Na+ concentrations, and leaf K+ concentrations. The accessions were clustered into four groups: the most tolerant, tolerant, moderately susceptible, and susceptible. From the most tolerant group, we selected six accessions, all of which were wild accessions adapted to coastal environments, as promising sources of salt tolerance because of their consistently high relative shoot biomass and relative quantum yield. Interestingly, variations in leaf Na+ concentration were observed between the accessions in the most tolerant group, suggesting different mechanisms were responsible for their salt tolerance. Phylogenetic analysis with nuclear DNA sequences revealed that salt tolerance had evolved independently at least four times in the genus Vigna, within a relatively short period. The findings suggested that simple genetic changes in a few genes might have greatly affected salt tolerances. The elucidation of genetic mechanisms of salt tolerances in the selected accessions may contribute to improving the poor salt tolerance in legume crops.

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