Fusarium oxysporum and Geotrichum candidum, which are among important pathogens of Solanum lycopersicum L. (Tomato), are sometimes misidentified during morphological misidentification. The study was carried out to eva...Fusarium oxysporum and Geotrichum candidum, which are among important pathogens of Solanum lycopersicum L. (Tomato), are sometimes misidentified during morphological misidentification. The study was carried out to evaluate molecular diversity of F. oxysporum and G. candidum isolated from two tomato varieties obtained from Akure, Ilorin and Ibadan, Nigeria. The tomato samples were collected and brought back to the laboratory for fungal isolation. Isolation of the pathogens were done following standard procedures. DNA extraction from pure cultures of the pathogens was done at the Centre Laboratory of University of Ibadan. Genetic relationships among the organisms were also estimated by constructing a Dendrogram through UPGMA using the Mega6 Software and genetic distance was computed also using the Mega6 Software. Five strains of F. oxysporum and seven strains of G. candidum were identified. Percentage similarity of the pathogens with those in GenBank was 99.17% - 100.00% for F. oxysporum and 98.48% - 100.00% for G. candidum. The T-01 marker showed the lowest major allele frequency of 0.0833, while T-10 marker has the highest value for major allele frequency of 0.6667 and an average value of 0.3958. Evolutionary relationship showed that the two strains of G. candidum (MN650247 and MN650250) were similar. The three strains of F. oxysporum (MN650246 and MN650248, MN650245 and MN650253) were also similar. Genetic distances among pairs of the fungal strains ranged from 0.12 to 6.30 in pairwise fashion, with an average of 1.32. Evolutionary relationship or closeness among strains of a fungal species can thus be said not to depend on location.展开更多
An experiment was carried out to evaluate the fungitoxic effect of Trichoderma longibrachiatum (Rifai) metabolite on F. oxysporum, A. niger and A. tamarii. The fungi were collected from the International Institute of ...An experiment was carried out to evaluate the fungitoxic effect of Trichoderma longibrachiatum (Rifai) metabolite on F. oxysporum, A. niger and A. tamarii. The fungi were collected from the International Institute of Tropical Agriculture (IITA) and Nigerian Institute of Science Laboratory Technology (NISLT). T. longibrachiatum was cultured on 1/4 strength Potato Dextrose Broth (PDB) following standard procedures. Its metabolite was extracted using 50 ml n-hexane with 50 ml Potato Dextrose Broth (PDB). The metabolite was purified by filter sterilization using a sterile 0.22 millipore filter disc after centrifuging at 900 rpm for 20 minutes. Petri plates of each fungus were later impregnated in triplicates with the T. longibrachiatum metabolites using four concentrations (10%, 25%, 50% and 100%), and three volumes (1 ml, 2 ml, and 3 ml). Petri plates of fungi without the metabolite and Petri Plates of fungi with n-hexane and PDB served as control. All Petri Plates were incubated at 28°C for 7 days. Radial and diametric growth of each fungus on all Petri Plates were taken daily at 24 hours intervals. Data obtained were analysed using SAS (version 9.3). Growth inhibition of F. oxysporum, A. niger and A. tamarii was significantly higher than in control in that order (P ≤ 0.05). Inhibition of the fungi by metabolites extracted with both PDB and n-hexane was significantly better than in control. Generally, inhibition by metabolite extracted with PDB was better than that extracted with n-hexane. Growth inhibition at all the concentrations of the metabolite was significantly better than in the control (P ≤ 0.05). Generally, inhibition at 100%, 50% and 25% concentrations was better than that at 10% concentration of the metabolite. Trichoderma longibrachiatum metabolite can thus be said to possess promising fungitoxic potential even at concentrations as low as 25%. Both PDB and n-hexane are good extraction media for the metabolite.展开更多
This study investigated the characterisation of Fusarium verticillioides strains using Amplified Fragments Length Polymorphism (AFLP) EcoR1-G/Mse1-C primer combination. This was done to determine the amount of genetic...This study investigated the characterisation of Fusarium verticillioides strains using Amplified Fragments Length Polymorphism (AFLP) EcoR1-G/Mse1-C primer combination. This was done to determine the amount of genetic variability present in F. verticillioides population. The objective of this study is to carry out molecular characterization of F. verticillioides strains from infected ear of maize. Six isolates were obtained in maize ear from 10 locations in three agro-ecological zones of Southwest Nigeria. Polymorphic bands detected were 164 from one base extension of EcoR1 and Mse1 primers in the selective amplification. Primer combination EC + MC produced the highest polymorphic bands of 58, while primer combination ET + MC had the highest percentage polymorphism (100%). Genetic similarity (67%) was observed among strains from Ibadan (IBD) (34, 36), Igbooho (IGH) (39), Ado-Ekiti (EKT) (46, 47), Saki (SAK) (52) and Igboora (IGB) (57, 58, 59 and 60). Strains 19 and 20 from Ilesha (ILH) had the highest pairwise similarity coefficient at 97% grouped in cluster II. The dendrogram delineated F. verticillioides strains into four major cluster groups with 77% similarity and other sub-groups within. Fusarium verticillioides strains could therefore be heterogeneous, and thus amplified fragment length polymorphism is an ideal tool for distinguishing the pathogenic variants of Fusarium verticillioides.展开更多
An experiment was conducted to examine probable impact of location and handling on the fungi commonly associated with rotting watermelon (Citrullus lanatus). The rotting watermelon samples were obtained from two vendo...An experiment was conducted to examine probable impact of location and handling on the fungi commonly associated with rotting watermelon (Citrullus lanatus). The rotting watermelon samples were obtained from two vendors each from five different markets (Bodija, Sango, Mokola, Eleyele, Agbowo and Ojoo) in Ibadan, Oyo state. They were placed in different sterile sample bags which were labeled appropriately before bringing them to the Pathology Laboratory, Department of Botany, University of Ibadan. Isolation of fungi from the rotting samples was carried out using pour plate method on acidified Potato Dextrose Agar (APDA). Pathogenicity test was also conducted for the isolated fungi. All experiments were done in duplicates and all plates were incubated at 25°C ± 2°C for 7 days. Pure cultures were obtained and identified and each isolated fungus was recorded as 1 which means present and 0 which means absent. The data obtained were analyzed using SAS version 9.3 at p ≤ 0.05. A total of three fungi were isolated viz., Aspergillus flavus, Saccharomyces cerevisae and Aspergillus niger. Occurrence of A. niger and A. flavus in samples obtained from Bodija, Mokola, Sango and Ojoo markets were significantly (P ≤ 0.05) higher than those from the other two markets. Occurrence of S. cerevisae in samples obtained from Bodija and Mokola markets were significantly (P ≤ 0.05) higher than those from the other three markets. Location had significant impact on the occurrence of isolated fungi in the rotting watermelons. However, handling by vendors had no significant impact on occurrence of the isolated fungi. Vendors and consumers are advised to be mindful of place of purchase and to also maintain good general hygiene before consumption.展开更多
文摘Fusarium oxysporum and Geotrichum candidum, which are among important pathogens of Solanum lycopersicum L. (Tomato), are sometimes misidentified during morphological misidentification. The study was carried out to evaluate molecular diversity of F. oxysporum and G. candidum isolated from two tomato varieties obtained from Akure, Ilorin and Ibadan, Nigeria. The tomato samples were collected and brought back to the laboratory for fungal isolation. Isolation of the pathogens were done following standard procedures. DNA extraction from pure cultures of the pathogens was done at the Centre Laboratory of University of Ibadan. Genetic relationships among the organisms were also estimated by constructing a Dendrogram through UPGMA using the Mega6 Software and genetic distance was computed also using the Mega6 Software. Five strains of F. oxysporum and seven strains of G. candidum were identified. Percentage similarity of the pathogens with those in GenBank was 99.17% - 100.00% for F. oxysporum and 98.48% - 100.00% for G. candidum. The T-01 marker showed the lowest major allele frequency of 0.0833, while T-10 marker has the highest value for major allele frequency of 0.6667 and an average value of 0.3958. Evolutionary relationship showed that the two strains of G. candidum (MN650247 and MN650250) were similar. The three strains of F. oxysporum (MN650246 and MN650248, MN650245 and MN650253) were also similar. Genetic distances among pairs of the fungal strains ranged from 0.12 to 6.30 in pairwise fashion, with an average of 1.32. Evolutionary relationship or closeness among strains of a fungal species can thus be said not to depend on location.
文摘An experiment was carried out to evaluate the fungitoxic effect of Trichoderma longibrachiatum (Rifai) metabolite on F. oxysporum, A. niger and A. tamarii. The fungi were collected from the International Institute of Tropical Agriculture (IITA) and Nigerian Institute of Science Laboratory Technology (NISLT). T. longibrachiatum was cultured on 1/4 strength Potato Dextrose Broth (PDB) following standard procedures. Its metabolite was extracted using 50 ml n-hexane with 50 ml Potato Dextrose Broth (PDB). The metabolite was purified by filter sterilization using a sterile 0.22 millipore filter disc after centrifuging at 900 rpm for 20 minutes. Petri plates of each fungus were later impregnated in triplicates with the T. longibrachiatum metabolites using four concentrations (10%, 25%, 50% and 100%), and three volumes (1 ml, 2 ml, and 3 ml). Petri plates of fungi without the metabolite and Petri Plates of fungi with n-hexane and PDB served as control. All Petri Plates were incubated at 28°C for 7 days. Radial and diametric growth of each fungus on all Petri Plates were taken daily at 24 hours intervals. Data obtained were analysed using SAS (version 9.3). Growth inhibition of F. oxysporum, A. niger and A. tamarii was significantly higher than in control in that order (P ≤ 0.05). Inhibition of the fungi by metabolites extracted with both PDB and n-hexane was significantly better than in control. Generally, inhibition by metabolite extracted with PDB was better than that extracted with n-hexane. Growth inhibition at all the concentrations of the metabolite was significantly better than in the control (P ≤ 0.05). Generally, inhibition at 100%, 50% and 25% concentrations was better than that at 10% concentration of the metabolite. Trichoderma longibrachiatum metabolite can thus be said to possess promising fungitoxic potential even at concentrations as low as 25%. Both PDB and n-hexane are good extraction media for the metabolite.
文摘This study investigated the characterisation of Fusarium verticillioides strains using Amplified Fragments Length Polymorphism (AFLP) EcoR1-G/Mse1-C primer combination. This was done to determine the amount of genetic variability present in F. verticillioides population. The objective of this study is to carry out molecular characterization of F. verticillioides strains from infected ear of maize. Six isolates were obtained in maize ear from 10 locations in three agro-ecological zones of Southwest Nigeria. Polymorphic bands detected were 164 from one base extension of EcoR1 and Mse1 primers in the selective amplification. Primer combination EC + MC produced the highest polymorphic bands of 58, while primer combination ET + MC had the highest percentage polymorphism (100%). Genetic similarity (67%) was observed among strains from Ibadan (IBD) (34, 36), Igbooho (IGH) (39), Ado-Ekiti (EKT) (46, 47), Saki (SAK) (52) and Igboora (IGB) (57, 58, 59 and 60). Strains 19 and 20 from Ilesha (ILH) had the highest pairwise similarity coefficient at 97% grouped in cluster II. The dendrogram delineated F. verticillioides strains into four major cluster groups with 77% similarity and other sub-groups within. Fusarium verticillioides strains could therefore be heterogeneous, and thus amplified fragment length polymorphism is an ideal tool for distinguishing the pathogenic variants of Fusarium verticillioides.
文摘An experiment was conducted to examine probable impact of location and handling on the fungi commonly associated with rotting watermelon (Citrullus lanatus). The rotting watermelon samples were obtained from two vendors each from five different markets (Bodija, Sango, Mokola, Eleyele, Agbowo and Ojoo) in Ibadan, Oyo state. They were placed in different sterile sample bags which were labeled appropriately before bringing them to the Pathology Laboratory, Department of Botany, University of Ibadan. Isolation of fungi from the rotting samples was carried out using pour plate method on acidified Potato Dextrose Agar (APDA). Pathogenicity test was also conducted for the isolated fungi. All experiments were done in duplicates and all plates were incubated at 25°C ± 2°C for 7 days. Pure cultures were obtained and identified and each isolated fungus was recorded as 1 which means present and 0 which means absent. The data obtained were analyzed using SAS version 9.3 at p ≤ 0.05. A total of three fungi were isolated viz., Aspergillus flavus, Saccharomyces cerevisae and Aspergillus niger. Occurrence of A. niger and A. flavus in samples obtained from Bodija, Mokola, Sango and Ojoo markets were significantly (P ≤ 0.05) higher than those from the other two markets. Occurrence of S. cerevisae in samples obtained from Bodija and Mokola markets were significantly (P ≤ 0.05) higher than those from the other three markets. Location had significant impact on the occurrence of isolated fungi in the rotting watermelons. However, handling by vendors had no significant impact on occurrence of the isolated fungi. Vendors and consumers are advised to be mindful of place of purchase and to also maintain good general hygiene before consumption.
