The companion fungus ( Grifola sp.) related to sclerotial formation from hyphae of Grifola umbellata (Pers.) Pilat was isolated from the cavity associated with sclerotia of G. umbellata in natural condition. Experimen...The companion fungus ( Grifola sp.) related to sclerotial formation from hyphae of Grifola umbellata (Pers.) Pilat was isolated from the cavity associated with sclerotia of G. umbellata in natural condition. Experimental results showed that the pure culture of G. umbellata was unable to form sclerotia, whereas sclerotia produced easily in flasks or on trunks when the companion fungus was inoculated together with strain of G. umbellata. The companion fungus is critical for sclerotium formation from hyphae of G. umbellata. Morphological differences were found in cultures of the two fungi. The companion fungus possesses thin-walled narrow hyphae, while G. umbellata is of wider hyphae which are either thick- or thin-walled.展开更多
The extracellular enzyme activities of sclerotia-forming and nonsclerotia- forming single spore strains of Morchella conica and M. crasspies were determined and compared. The non sclerotia-forming strains of M. conica...The extracellular enzyme activities of sclerotia-forming and nonsclerotia- forming single spore strains of Morchella conica and M. crasspies were determined and compared. The non sclerotia-forming strains of M. conica exhibited higher aver- age activities of protease, catalase and xylanase but lower laccase activity than those of sclerotia-forming strains. However, the differences did not reach significance level. The soluble amylases activity of M. crasspies was significantly higher than that of M. conica, while the mean activity of other enzymes had differences between them, but the differences did not reach significance level.展开更多
We studied the relationship between sclerotia formation and aflatoxin production by Aspergillusflavus strains isolated from maize kernels from Nandi County. Isolates recovered from maize kernels were tested for their ...We studied the relationship between sclerotia formation and aflatoxin production by Aspergillusflavus strains isolated from maize kernels from Nandi County. Isolates recovered from maize kernels were tested for their ability to form sclerotia on different growth media. PCR analysis was done on the isolates to detect 2 structural genes, aflD and aflQ, involved in aflatoxin biosynthesis pathway. Positive A. flavus isolates for one or both genes were grown on Yeast Extract Sucrose Agar medium and aflatoxins quantified using LCMSMS. All the isolates formed large sclerotia and their formation was influenced by media type but could not be related to amount of aflatoxins produced both in vivo and in vitro. Though sclerotia are perennating structures and so contribute to survival index of a fungus, their initiation is regulated by external factors though ability to form is genetic. This brings ambiguity of their presence or abundance as a measure of toxicity.展开更多
The effects of substrate composition and temperature on myceilal growth and sclerotium production in Grlfola umbellate （Pers.） Pilaet were Investigated In the present study. The Induction of sclerotla of G. umbellat...The effects of substrate composition and temperature on myceilal growth and sclerotium production in Grlfola umbellate （Pers.） Pilaet were Investigated In the present study. The Induction of sclerotla of G. umbellate was affected greatly by the type of medium, as well as the type of carbon source. Malt-extract agar was able to induce the production of sclerotia. The production of sclerotia was also observed when the carbon source in the GPC agar medium （glucose 20 g/L, peptone 6 g/L, corn steep liquor 10 g/L, and agar 15 g/L） was replaced with glycerol or mannitol. Altering the composition of the GPC medium with milk powder, thiamine hydrochlorlde, extract of Armlllarla mellea, active clay, dlatomite, kaolin, or arginlne did not induce the production of sclerotla. A temperature range of 18-25 ℃ was suitable for both mycellai growth and sclerotium formation. Glycerol significantly Induced slerotium formation on nutrient supplemented with sawdust substrates In bottle culture. 24S-Polyporusterone A and polyporusterone B were assayed In samples of natural and cultured sclerotla. Both natural and cultured sclerotla contained 24S- polyporusterone A and polyporusterone B.展开更多
Rice sheath blight pathogen,Rhizoctonia solani,produces numerous sclerotia to overwinter.As a rich source of nutrients in the soil,sclerotia may lead to the change of soil microbiota.For this purpose,we amended the sc...Rice sheath blight pathogen,Rhizoctonia solani,produces numerous sclerotia to overwinter.As a rich source of nutrients in the soil,sclerotia may lead to the change of soil microbiota.For this purpose,we amended the sclerotia of R.solani in soil and analyzed the changes in bacterial microbiota within the soil at different time points.At the phyla level,Proteobacteria,Acidobacteria,Bacteroidetes,Actinobacteria,Chloroflexi and Firmicutes showed varied abundance in the amended soil samples compared to those in the control.An increased abundance of ammonia-oxidizing bacterium(AOB)Nitrosospira and Nitrite oxidizing bacteria(NOB)i.e.,Nitrospira was observed,where the latter is reportedly involved in the nitrifier denitrification.Moreover,Thiobacillus,Gemmatimonas,Anaeromyxobacter and Geobacter,the vital players in denitrification,N2O reduction and reductive nitrogen transformation,respectively,depicted enhanced abundance in R.solani sclerotia-amended samples.Furthermore,asymbiotic nitrogen-fixing bacteria,notably,Azotobacter as well as Microvirga and Phenylobacterium with nitrogen-fixing potential also enriched in the amended samples compared to the control.Plant growth promoting bacteria,such as Kribbella,Chitinophaga and Flavisolibacter also enriched in the sclerotia-amended soil.As per our knowledge,this study is of its kind where pathogenic fungal sclerotia activated microbes with a potential role in N transformation and provided clues about the ecological functions of R.solani sclerotia on the stimulation of bacterial genera involved in different processes of N-cycle within the soil in the absence of host plants.展开更多
文摘The companion fungus ( Grifola sp.) related to sclerotial formation from hyphae of Grifola umbellata (Pers.) Pilat was isolated from the cavity associated with sclerotia of G. umbellata in natural condition. Experimental results showed that the pure culture of G. umbellata was unable to form sclerotia, whereas sclerotia produced easily in flasks or on trunks when the companion fungus was inoculated together with strain of G. umbellata. The companion fungus is critical for sclerotium formation from hyphae of G. umbellata. Morphological differences were found in cultures of the two fungi. The companion fungus possesses thin-walled narrow hyphae, while G. umbellata is of wider hyphae which are either thick- or thin-walled.
基金Supported by China Agriculture Research System(CARS24)National High Technology Research and Development Program of China(863 Program,2007AA021506)~~
文摘The extracellular enzyme activities of sclerotia-forming and nonsclerotia- forming single spore strains of Morchella conica and M. crasspies were determined and compared. The non sclerotia-forming strains of M. conica exhibited higher aver- age activities of protease, catalase and xylanase but lower laccase activity than those of sclerotia-forming strains. However, the differences did not reach significance level. The soluble amylases activity of M. crasspies was significantly higher than that of M. conica, while the mean activity of other enzymes had differences between them, but the differences did not reach significance level.
文摘We studied the relationship between sclerotia formation and aflatoxin production by Aspergillusflavus strains isolated from maize kernels from Nandi County. Isolates recovered from maize kernels were tested for their ability to form sclerotia on different growth media. PCR analysis was done on the isolates to detect 2 structural genes, aflD and aflQ, involved in aflatoxin biosynthesis pathway. Positive A. flavus isolates for one or both genes were grown on Yeast Extract Sucrose Agar medium and aflatoxins quantified using LCMSMS. All the isolates formed large sclerotia and their formation was influenced by media type but could not be related to amount of aflatoxins produced both in vivo and in vitro. Though sclerotia are perennating structures and so contribute to survival index of a fungus, their initiation is regulated by external factors though ability to form is genetic. This brings ambiguity of their presence or abundance as a measure of toxicity.
基金Supported by the National Science Foundation of China （30325047, 30470042）, the 10th Five Years Key Programs for Science and Technology Development of China （2001 BA701A62）.
文摘The effects of substrate composition and temperature on myceilal growth and sclerotium production in Grlfola umbellate （Pers.） Pilaet were Investigated In the present study. The Induction of sclerotla of G. umbellate was affected greatly by the type of medium, as well as the type of carbon source. Malt-extract agar was able to induce the production of sclerotia. The production of sclerotia was also observed when the carbon source in the GPC agar medium （glucose 20 g/L, peptone 6 g/L, corn steep liquor 10 g/L, and agar 15 g/L） was replaced with glycerol or mannitol. Altering the composition of the GPC medium with milk powder, thiamine hydrochlorlde, extract of Armlllarla mellea, active clay, dlatomite, kaolin, or arginlne did not induce the production of sclerotla. A temperature range of 18-25 ℃ was suitable for both mycellai growth and sclerotium formation. Glycerol significantly Induced slerotium formation on nutrient supplemented with sawdust substrates In bottle culture. 24S-Polyporusterone A and polyporusterone B were assayed In samples of natural and cultured sclerotla. Both natural and cultured sclerotla contained 24S- polyporusterone A and polyporusterone B.
基金funded by the National Key R&D Program(grant number No.2017YFD0200600)and the earmarked fund for CARS-12.
文摘Rice sheath blight pathogen,Rhizoctonia solani,produces numerous sclerotia to overwinter.As a rich source of nutrients in the soil,sclerotia may lead to the change of soil microbiota.For this purpose,we amended the sclerotia of R.solani in soil and analyzed the changes in bacterial microbiota within the soil at different time points.At the phyla level,Proteobacteria,Acidobacteria,Bacteroidetes,Actinobacteria,Chloroflexi and Firmicutes showed varied abundance in the amended soil samples compared to those in the control.An increased abundance of ammonia-oxidizing bacterium(AOB)Nitrosospira and Nitrite oxidizing bacteria(NOB)i.e.,Nitrospira was observed,where the latter is reportedly involved in the nitrifier denitrification.Moreover,Thiobacillus,Gemmatimonas,Anaeromyxobacter and Geobacter,the vital players in denitrification,N2O reduction and reductive nitrogen transformation,respectively,depicted enhanced abundance in R.solani sclerotia-amended samples.Furthermore,asymbiotic nitrogen-fixing bacteria,notably,Azotobacter as well as Microvirga and Phenylobacterium with nitrogen-fixing potential also enriched in the amended samples compared to the control.Plant growth promoting bacteria,such as Kribbella,Chitinophaga and Flavisolibacter also enriched in the sclerotia-amended soil.As per our knowledge,this study is of its kind where pathogenic fungal sclerotia activated microbes with a potential role in N transformation and provided clues about the ecological functions of R.solani sclerotia on the stimulation of bacterial genera involved in different processes of N-cycle within the soil in the absence of host plants.
