Plant secondary metabolites play vital role in plant stress response. In this study we investigated whether root colonization of tomato (Solanum lycopersicum) infected by Trichoderma harzianum leads to alterations i...Plant secondary metabolites play vital role in plant stress response. In this study we investigated whether root colonization of tomato (Solanum lycopersicum) infected by Trichoderma harzianum leads to alterations in the biosynthesis of secondary plant metabolites including phytohormones and osmolyte proline under drought stress. Exposure of tomato to drought caused a drastic decline in plant growth and physiological parameters. Tomato inoculated with T. harzianum showed increased root and shoot growth and chlorophyll pigments as compared to uninoculated controls as well as drought stressed plants. Proline and total soluble protein content was increased in plants inoculated with T. harzianum under both normal as well as drought conditions. An obvious increase in phenol and flavonoid content was observed due to T. haczianum. In addition, T. hat-zianum inoculated plants maintained higher levels of growth regulators indole acetic acid, indole butyric acid, and gibberellic acid under drought stress. Improved secondary metabolites which play an important role in plant stress tolerance by T. hat-zianum may have coordinately worked for bringing the growth regulation by protecting membranes from reactive oxygen species (ROS) and enhance plant growth through accessing more nutrients by root system.展开更多
Southern corn leaf blight(SCLB)disease caused by Cochliobolus heterostrophus is one of the major threats to corn production worldwide.The synergistic application of low toxic chemical fungicide and biocontrol agents c...Southern corn leaf blight(SCLB)disease caused by Cochliobolus heterostrophus is one of the major threats to corn production worldwide.The synergistic application of low toxic chemical fungicide and biocontrol agents could improve biocontrol stability and efficiency against plant diseases,which ultimately reduce use of chemical fungicide.Trichoderma spp.,well-known biocontrol fungi have been used to control some foliar diseases.However,few works have been reported on synergistic application of chemical fungicide and Trichoderma against foliar diseases.This study was aimed to investigate the control effect on the synergistic application of Trichoderma harzianum SH2303 and difenoconazole-propiconazole(DP)against SCLB.Results showed that the synergistic application of DP and SH2303 reduced the leaf spot area compared to the control.The efficacy of synergistic application of DP+SH2303 against SCLB could last for 15–20 d in pot trial under the greenhouse condition.Under the natural field condition,maize treated with DP+DP and DP+SH2303 showed 60%control,which was higher than that of SH2303+DP(45%)and SH2303+SH2303(35%).All these treatments induced the synthesis of defense-related enzymes(phenylalanine ammonia lyase(PAL),catalase(CAT),and superoxide dismutase(SOD))and the defence-related gene expression of SA pathway(PR1).Taken together the in-vitro leaf test and field trial,the control of SCLB by synergistic application of DP+SH2303 was similar to that of DP+DP.Among synergistic application,the sequential application of DP+SH2303 showed better control than the sequential application of SH2303+DP.It was concluded that the synergistic application of chemical fungicide(DP)and biocontrol agent(T.harzianum SH2303)could be used to reduce the chemical fungicide and to reduce the SCLB diseases in maize,which provided alternative approach to realize an eco-friendly controlling of the foliar disease.展开更多
The effects of biofungicide formula containing the biocontrol agent Trichoderma harzianum (Jn14) as wettable powder in combination with the fungicides pyrimethanil and a mixture of cyprodinil and flydioxonil on Botryt...The effects of biofungicide formula containing the biocontrol agent Trichoderma harzianum (Jn14) as wettable powder in combination with the fungicides pyrimethanil and a mixture of cyprodinil and flydioxonil on Botrytis cinerea of strawberry in vitro, in vivo and in greenhouse were studied. The pathogen B. cinerea was more affected in vitro by low concentrations of the fungicides tested above 0.4 μg·ml-1 than the bioagent T. harzianum (Jn14). The later was almost insensitive to pyrimethanil. In the same direction, gray mould disease severity on strawberry detached leaves and whole plants was reduced up to 89% by the tested fungicides, compared to the control, while the application of T. harzianum (Jn14) alone reduced disease severity up to 45% on strawberry detached leaves, compared to the control. In the integrated control approach, the combination of T. harzianum (Jn14) with higher concentrations of the tested fungicides (ED50) completely inhibited strawberry gray mould disease severity in pots and the greenhouse.展开更多
Objective: To test the effectiveness of conidial spore formulations [Aspergillus tubingensis(A.tubingensis) and Trichoderma harzianum(T.harzianum)] against tropical bed bugs, Cimex hemipterus.Methods: Spore formulatio...Objective: To test the effectiveness of conidial spore formulations [Aspergillus tubingensis(A.tubingensis) and Trichoderma harzianum(T.harzianum)] against tropical bed bugs, Cimex hemipterus.Methods: Spore formulations were made from two fungal strains, T.harzianum and A.tubingensis.The bed bugs were exposed to the conidial spores placed soaked onto a fabric cloth for 1 h and the mortality counts were recorded daily until 14 days.Results: Mean survival times based on Kaplan–Meier survival analysis showed no significant differences between all the concentrations in both the fungal isolates:T.harzianum and A.tubingensis.However, the evaluation of both the isolates in terms of virulence resulted in low lethal hours in all the concentrations except for the high concentration of A.tubingensis(LT_(50)= 44.629 h) at the conidial exposure of 1 × 10~6 spores/mL.Rapid mortality of the bed bugs was observed from Day 6 to Day 12, ranging from 13% to 90% in all three concentrations of A.tubingensis.With reference to the T.harzianum exposure, the concentration of 1 × 10~4 spores/mL displayed a gradual increase in the percentage mortality of 90 on Day 14.Conclusions: Approaches to the bed bugs treatment should be explored in-depth using a natural biological agent like fungus especially A.tubingensis to reduce this pest population, in order to replace chemical methods.展开更多
A transcriptomic database was constructed to study the biocontrol mechanisms of Trichoderma harzianum ACCC30371 using high quality UniGenes following growth in eight culture media[(1/2PD,minimal medium MM(containing d...A transcriptomic database was constructed to study the biocontrol mechanisms of Trichoderma harzianum ACCC30371 using high quality UniGenes following growth in eight culture media[(1/2PD,minimal medium MM(containing dextrose 10 g L^-1),C starvation medium(derived from MM without dextrose),N starvation medium(derived from MM without ammonium sulphate),and four kinds of phytopathogenic fungi cell wall media].A 4 Gbp transcriptome was generated and 96.7%of the database had a sequencing error rate less than 1%.A total of 25,013 UniGene sequences were obtained with a mean length of 1135 nt.There were 2571 sequences longer than 3000 nt.The National Center for Biotechnology Information Accession number of this transcriptome is SRR8382572.There were 16,360 Unigenes annotated to the Nr protein database,9875 to the SwissProt database,10,266 to the KEGG database,7164 to the COG database,and 1508 to the GO database along with their protein functional annotations.There were 16,723 functional genes identified.We identified 402 bio-control genes,including 14 related to competition,311 to mycoparasitism,76 to antibiosis,and one related to eliciting a plant response.This shows that T.harzianum ACCC30371 has integrated biocontrol mechanisms,and of these mechanisms,mycoparasitism is the most prevalent.Antibiosis and induced systemic resistance also play important roles.These results provide a foundation for further research into the biocontrol mechanisms of Trichoderma,as well as the development and utilization of biological fungicides.展开更多
Bacillus amyloliquefaciens Bc2 and Trichderma harzianum TR were used to evaluate their growth-promoting activity on cultivated strawberries, under laboratory and field conditions, and we have noticed that the percenta...Bacillus amyloliquefaciens Bc2 and Trichderma harzianum TR were used to evaluate their growth-promoting activity on cultivated strawberries, under laboratory and field conditions, and we have noticed that the percentage of achene germination is important for ones treated with TR (=97%) followed by those treated with Bc2 strain (=90%) and the control (=84%). Inoculations on field showed that on untreated soil with insecticide, TR is effective and allows the development of plants and extends the duration of flowering and fruiting. On treated soil, Bc2 clearly promotes the growth and development of strawberry seedlings and its role as plant growth promoting microorganisms has been proved.展开更多
The increasingly strict regulation of the use of phytosanitary products and the will of the populations to move towards sustainable development allow bio-sourced products and more particularly for biocontrol in the fi...The increasingly strict regulation of the use of phytosanitary products and the will of the populations to move towards sustainable development allow bio-sourced products and more particularly for biocontrol in the field of pesticides to progress. The study carried out here concerns the evaluation of the potency of Bacillus amyloliquefaciens Bc2 and Trichoderma harzianum to fight against strawberry cultures infected with anthracnose (Fragaria × ananassa Duch.). The studies were carried out in the laboratory and in the field. The results indicate that B. amyloliquefaciens Bc2 and Trichoderma harzianum TR are effective for the biological control of anthracnose, gray mold and powdery mildew on strawberries grown in field conditions. The increase in plant size and the number of fruits produced with these control agents has also been observed.展开更多
Biological control of plant diseases makes extensive use of the antagonists. The effectiveness of the control depends on the choice of an effective antagonist strains from criteria of implying a good knowledge of biol...Biological control of plant diseases makes extensive use of the antagonists. The effectiveness of the control depends on the choice of an effective antagonist strains from criteria of implying a good knowledge of biological peculiarities of the material used. In this study, the antagonistic activities of nine isolates of Bacillus amyloliquefaciens and one isolate of Trichoderma harzianum were tested in vitro against seven strains of Colletotrichum acutatum, the causal agent of strawberry anthracnose. It was found that T. harzianum and B. amyloliquefaciens strains showed the ability to inhibit the mycelial growth of the pathogen by dual culture technique by more than 50 percent. The nonvolatile substances produced by the antagonists showed high inhibition percentages that are more than 99 percent, meanwhile their volatile compounds inhibited the mycelial growth of C. acutatum strains with low inhibition percentages starting from 30 percent except the substances produced by B. amyloliquefaciens Bc2 that showed a high inhibition percentage of more than 70 percent.展开更多
Trichoderma harzianum is a widely used biocontrol fungus. The growth promoting effect of strain Trichoderma harzianum TL-1 on tomato and pepper and its biological control effects against tomato seedling damping-off an...Trichoderma harzianum is a widely used biocontrol fungus. The growth promoting effect of strain Trichoderma harzianum TL-1 on tomato and pepper and its biological control effects against tomato seedling damping-off and pepper blight were investigated through pot experiments. The results showed that the stain TL-1 had significant promotion effect on growth of pepper and tomato in sterilized and natural soils. With the application dose of 3. 0 and 0. 5g/ pot,their dry weight were increased up to 46% and 150% compared with control,respectively. In addition,TL-1 had good control effects against tomato seedling damping-off and pepper blight. Compared with fungicide treatment,TL-1 treatment could control diseases for long term,without repeat occurrence of diseases.展开更多
This study describes a novel dark-green spore producing strain of Trichoderma harzianum exhibiting higher activities of cellulase, hemicellulase and ligninase on specific plate assays. To assess the cellulase producti...This study describes a novel dark-green spore producing strain of Trichoderma harzianum exhibiting higher activities of cellulase, hemicellulase and ligninase on specific plate assays. To assess the cellulase production in detail, basal salt medium (BSM) was supplemented with synthetic [carboxymethyl cellulose (CMC), glucose, sucrose, dextrose, lactose or maltose] and natural (flours of banana, banana peel, jack seed, potato or tapioca) carbon as well as nitrogen (yeast extract, beef extract, peptone, NaNO3 or NH4NO3) sources. Temperature and pH optima were 28?C and 4, respectively for the growth of the fungus in CMC- BSM with 146 U/ml cellulase activity. Flours of potato and banana supported comparable yields of cellulase to that of CMC (147 U/ml and 168 U/ml, respectively), while sodium nitrate was the preferred nitrogen source (150 U/ml). The water soluble yellowish-green pigment (a probable siderophore) extracted from the spores showed an absorption maximum at 414 nm. To comprise, this fungus shows the complete lignocellulolytic potential which offers great industrial significance, especially for the ethanol production from the lignocellulosic waste coupled with the production of a new pigment.展开更多
Trichoderma harzianum Rifai SKW-36 produced two kinds of D-amino acid oxidizing enzymes. One enzyme was D-aspartate oxidase acting on acidic D-amino acids such as D-aspartate and D-glutamate and another one was D-amin...Trichoderma harzianum Rifai SKW-36 produced two kinds of D-amino acid oxidizing enzymes. One enzyme was D-aspartate oxidase acting on acidic D-amino acids such as D-aspartate and D-glutamate and another one was D-amino acid oxidase acting on neutral D-amino acid such as D-phenylalanine and D-methionine. These enzymes in the cell-free extract were separated by DEAE-Toyopearl ion-exchange column chromatography. Casamino acids, peptone, and yeast extract as carbon and nitrogen sources were effective for the production of the enzymes. No D-amino acid tested induced the production of the enzymes. Casamino acid (0.33%) as carbon and nitrogen source gave a highest specific activity of D-aspartate oxidase among media tested. D-Aspartate oxidase, which was purified by four-step column chromatography in addition to ammonium sulfate precipitation, exhibited a subunit molecular mass of 40 kDa by SDS-PAGE analysis. D-Aspartate, D-glutamate and N-methyl-D- aspartate were oxidized as substrates with the specific activities of 7.80 U/mg, 4.90 U/mg, and 4.22 U/mg, respectively. D-Asparagine, D-glutamine, D-alanine, and D-valine were slightly oxidized. No other D- amino acids tested were inert. The enzyme exhibited relatively wide substrate specificity compared to D-aspartate oxidases reported so far. The pH and temperature optima were 7.5 - 8.0 and 35°C, respectively. The enzyme was stable at pH 6.0 - 9.0. About 75% of the enzyme activity was retained even after treating the enzyme at 50°C for 10 min. The enzyme activity was inhibited not by benzoate and tartrate, but 60% and 24% by fumarate and malonate, respectively.展开更多
[Objective] The paper was to explore the optimum dosage and application pattern of Trichoderma harzianum for controlling Potato Verticillium wilt. [ Method] Two trials, sowing seed tubers in bacterial manure, sowing s...[Objective] The paper was to explore the optimum dosage and application pattern of Trichoderma harzianum for controlling Potato Verticillium wilt. [ Method] Two trials, sowing seed tubers in bacterial manure, sowing seed tubers in bacterial manure + root irrigation after seedling emergence, were conducted in the paper. [Result] T.harzianum could effectively control potato early dying and promote potato growth, thereby increasing potato yield. The control effects of sowing tuber in 300 times of bacterial manure + root irrigation with 300 times of conidia suspension after seedling emergence were ideal ; the highest control effect and the highest saved yield loss were 72.60% and 33.33%, respectively. [ Conclusion] The paper provides reference for field application of T. harzianum.展开更多
基金the Deanship of Scientific Research at King Saud University,Saudi Arabia(RGP-271)
文摘Plant secondary metabolites play vital role in plant stress response. In this study we investigated whether root colonization of tomato (Solanum lycopersicum) infected by Trichoderma harzianum leads to alterations in the biosynthesis of secondary plant metabolites including phytohormones and osmolyte proline under drought stress. Exposure of tomato to drought caused a drastic decline in plant growth and physiological parameters. Tomato inoculated with T. harzianum showed increased root and shoot growth and chlorophyll pigments as compared to uninoculated controls as well as drought stressed plants. Proline and total soluble protein content was increased in plants inoculated with T. harzianum under both normal as well as drought conditions. An obvious increase in phenol and flavonoid content was observed due to T. haczianum. In addition, T. hat-zianum inoculated plants maintained higher levels of growth regulators indole acetic acid, indole butyric acid, and gibberellic acid under drought stress. Improved secondary metabolites which play an important role in plant stress tolerance by T. hat-zianum may have coordinately worked for bringing the growth regulation by protecting membranes from reactive oxygen species (ROS) and enhance plant growth through accessing more nutrients by root system.
基金supported by the National Key Research and Development Program of China (2017YFD0201108, 2017YFD0200901)the National Natural Science Foundation of China (31672072, 31872015, 31750110455)+2 种基金the earmarked fund for China Agriculture Research System (CARS-02)the Key National R&D Programs of China-Key International Intergovernmental Scientific and Technological Innovation Cooperation Projects (2017YFE0104900)the Agriculture Research System of Shanghai, China (201710)
文摘Southern corn leaf blight(SCLB)disease caused by Cochliobolus heterostrophus is one of the major threats to corn production worldwide.The synergistic application of low toxic chemical fungicide and biocontrol agents could improve biocontrol stability and efficiency against plant diseases,which ultimately reduce use of chemical fungicide.Trichoderma spp.,well-known biocontrol fungi have been used to control some foliar diseases.However,few works have been reported on synergistic application of chemical fungicide and Trichoderma against foliar diseases.This study was aimed to investigate the control effect on the synergistic application of Trichoderma harzianum SH2303 and difenoconazole-propiconazole(DP)against SCLB.Results showed that the synergistic application of DP and SH2303 reduced the leaf spot area compared to the control.The efficacy of synergistic application of DP+SH2303 against SCLB could last for 15–20 d in pot trial under the greenhouse condition.Under the natural field condition,maize treated with DP+DP and DP+SH2303 showed 60%control,which was higher than that of SH2303+DP(45%)and SH2303+SH2303(35%).All these treatments induced the synthesis of defense-related enzymes(phenylalanine ammonia lyase(PAL),catalase(CAT),and superoxide dismutase(SOD))and the defence-related gene expression of SA pathway(PR1).Taken together the in-vitro leaf test and field trial,the control of SCLB by synergistic application of DP+SH2303 was similar to that of DP+DP.Among synergistic application,the sequential application of DP+SH2303 showed better control than the sequential application of SH2303+DP.It was concluded that the synergistic application of chemical fungicide(DP)and biocontrol agent(T.harzianum SH2303)could be used to reduce the chemical fungicide and to reduce the SCLB diseases in maize,which provided alternative approach to realize an eco-friendly controlling of the foliar disease.
文摘The effects of biofungicide formula containing the biocontrol agent Trichoderma harzianum (Jn14) as wettable powder in combination with the fungicides pyrimethanil and a mixture of cyprodinil and flydioxonil on Botrytis cinerea of strawberry in vitro, in vivo and in greenhouse were studied. The pathogen B. cinerea was more affected in vitro by low concentrations of the fungicides tested above 0.4 μg·ml-1 than the bioagent T. harzianum (Jn14). The later was almost insensitive to pyrimethanil. In the same direction, gray mould disease severity on strawberry detached leaves and whole plants was reduced up to 89% by the tested fungicides, compared to the control, while the application of T. harzianum (Jn14) alone reduced disease severity up to 45% on strawberry detached leaves, compared to the control. In the integrated control approach, the combination of T. harzianum (Jn14) with higher concentrations of the tested fungicides (ED50) completely inhibited strawberry gray mould disease severity in pots and the greenhouse.
基金Supported by Universiti Sains Malaysia(Grant No.304/PBIOLOGI/6313030)
文摘Objective: To test the effectiveness of conidial spore formulations [Aspergillus tubingensis(A.tubingensis) and Trichoderma harzianum(T.harzianum)] against tropical bed bugs, Cimex hemipterus.Methods: Spore formulations were made from two fungal strains, T.harzianum and A.tubingensis.The bed bugs were exposed to the conidial spores placed soaked onto a fabric cloth for 1 h and the mortality counts were recorded daily until 14 days.Results: Mean survival times based on Kaplan–Meier survival analysis showed no significant differences between all the concentrations in both the fungal isolates:T.harzianum and A.tubingensis.However, the evaluation of both the isolates in terms of virulence resulted in low lethal hours in all the concentrations except for the high concentration of A.tubingensis(LT_(50)= 44.629 h) at the conidial exposure of 1 × 10~6 spores/mL.Rapid mortality of the bed bugs was observed from Day 6 to Day 12, ranging from 13% to 90% in all three concentrations of A.tubingensis.With reference to the T.harzianum exposure, the concentration of 1 × 10~4 spores/mL displayed a gradual increase in the percentage mortality of 90 on Day 14.Conclusions: Approaches to the bed bugs treatment should be explored in-depth using a natural biological agent like fungus especially A.tubingensis to reduce this pest population, in order to replace chemical methods.
基金The work was supported by the Fundamental Research Funds of the Central University,China(Grant Number 2572017AA03 and Grant Number 2572014BA15).
文摘A transcriptomic database was constructed to study the biocontrol mechanisms of Trichoderma harzianum ACCC30371 using high quality UniGenes following growth in eight culture media[(1/2PD,minimal medium MM(containing dextrose 10 g L^-1),C starvation medium(derived from MM without dextrose),N starvation medium(derived from MM without ammonium sulphate),and four kinds of phytopathogenic fungi cell wall media].A 4 Gbp transcriptome was generated and 96.7%of the database had a sequencing error rate less than 1%.A total of 25,013 UniGene sequences were obtained with a mean length of 1135 nt.There were 2571 sequences longer than 3000 nt.The National Center for Biotechnology Information Accession number of this transcriptome is SRR8382572.There were 16,360 Unigenes annotated to the Nr protein database,9875 to the SwissProt database,10,266 to the KEGG database,7164 to the COG database,and 1508 to the GO database along with their protein functional annotations.There were 16,723 functional genes identified.We identified 402 bio-control genes,including 14 related to competition,311 to mycoparasitism,76 to antibiosis,and one related to eliciting a plant response.This shows that T.harzianum ACCC30371 has integrated biocontrol mechanisms,and of these mechanisms,mycoparasitism is the most prevalent.Antibiosis and induced systemic resistance also play important roles.These results provide a foundation for further research into the biocontrol mechanisms of Trichoderma,as well as the development and utilization of biological fungicides.
文摘Bacillus amyloliquefaciens Bc2 and Trichderma harzianum TR were used to evaluate their growth-promoting activity on cultivated strawberries, under laboratory and field conditions, and we have noticed that the percentage of achene germination is important for ones treated with TR (=97%) followed by those treated with Bc2 strain (=90%) and the control (=84%). Inoculations on field showed that on untreated soil with insecticide, TR is effective and allows the development of plants and extends the duration of flowering and fruiting. On treated soil, Bc2 clearly promotes the growth and development of strawberry seedlings and its role as plant growth promoting microorganisms has been proved.
文摘The increasingly strict regulation of the use of phytosanitary products and the will of the populations to move towards sustainable development allow bio-sourced products and more particularly for biocontrol in the field of pesticides to progress. The study carried out here concerns the evaluation of the potency of Bacillus amyloliquefaciens Bc2 and Trichoderma harzianum to fight against strawberry cultures infected with anthracnose (Fragaria × ananassa Duch.). The studies were carried out in the laboratory and in the field. The results indicate that B. amyloliquefaciens Bc2 and Trichoderma harzianum TR are effective for the biological control of anthracnose, gray mold and powdery mildew on strawberries grown in field conditions. The increase in plant size and the number of fruits produced with these control agents has also been observed.
文摘Biological control of plant diseases makes extensive use of the antagonists. The effectiveness of the control depends on the choice of an effective antagonist strains from criteria of implying a good knowledge of biological peculiarities of the material used. In this study, the antagonistic activities of nine isolates of Bacillus amyloliquefaciens and one isolate of Trichoderma harzianum were tested in vitro against seven strains of Colletotrichum acutatum, the causal agent of strawberry anthracnose. It was found that T. harzianum and B. amyloliquefaciens strains showed the ability to inhibit the mycelial growth of the pathogen by dual culture technique by more than 50 percent. The nonvolatile substances produced by the antagonists showed high inhibition percentages that are more than 99 percent, meanwhile their volatile compounds inhibited the mycelial growth of C. acutatum strains with low inhibition percentages starting from 30 percent except the substances produced by B. amyloliquefaciens Bc2 that showed a high inhibition percentage of more than 70 percent.
基金Supported by Natural Science Fund of Hainan Province in 2013"DNA Barcode Research of Medical Plants in Euphorbiaceae in Hainan Province"(813190)
文摘Trichoderma harzianum is a widely used biocontrol fungus. The growth promoting effect of strain Trichoderma harzianum TL-1 on tomato and pepper and its biological control effects against tomato seedling damping-off and pepper blight were investigated through pot experiments. The results showed that the stain TL-1 had significant promotion effect on growth of pepper and tomato in sterilized and natural soils. With the application dose of 3. 0 and 0. 5g/ pot,their dry weight were increased up to 46% and 150% compared with control,respectively. In addition,TL-1 had good control effects against tomato seedling damping-off and pepper blight. Compared with fungicide treatment,TL-1 treatment could control diseases for long term,without repeat occurrence of diseases.
文摘This study describes a novel dark-green spore producing strain of Trichoderma harzianum exhibiting higher activities of cellulase, hemicellulase and ligninase on specific plate assays. To assess the cellulase production in detail, basal salt medium (BSM) was supplemented with synthetic [carboxymethyl cellulose (CMC), glucose, sucrose, dextrose, lactose or maltose] and natural (flours of banana, banana peel, jack seed, potato or tapioca) carbon as well as nitrogen (yeast extract, beef extract, peptone, NaNO3 or NH4NO3) sources. Temperature and pH optima were 28?C and 4, respectively for the growth of the fungus in CMC- BSM with 146 U/ml cellulase activity. Flours of potato and banana supported comparable yields of cellulase to that of CMC (147 U/ml and 168 U/ml, respectively), while sodium nitrate was the preferred nitrogen source (150 U/ml). The water soluble yellowish-green pigment (a probable siderophore) extracted from the spores showed an absorption maximum at 414 nm. To comprise, this fungus shows the complete lignocellulolytic potential which offers great industrial significance, especially for the ethanol production from the lignocellulosic waste coupled with the production of a new pigment.
文摘Trichoderma harzianum Rifai SKW-36 produced two kinds of D-amino acid oxidizing enzymes. One enzyme was D-aspartate oxidase acting on acidic D-amino acids such as D-aspartate and D-glutamate and another one was D-amino acid oxidase acting on neutral D-amino acid such as D-phenylalanine and D-methionine. These enzymes in the cell-free extract were separated by DEAE-Toyopearl ion-exchange column chromatography. Casamino acids, peptone, and yeast extract as carbon and nitrogen sources were effective for the production of the enzymes. No D-amino acid tested induced the production of the enzymes. Casamino acid (0.33%) as carbon and nitrogen source gave a highest specific activity of D-aspartate oxidase among media tested. D-Aspartate oxidase, which was purified by four-step column chromatography in addition to ammonium sulfate precipitation, exhibited a subunit molecular mass of 40 kDa by SDS-PAGE analysis. D-Aspartate, D-glutamate and N-methyl-D- aspartate were oxidized as substrates with the specific activities of 7.80 U/mg, 4.90 U/mg, and 4.22 U/mg, respectively. D-Asparagine, D-glutamine, D-alanine, and D-valine were slightly oxidized. No other D- amino acids tested were inert. The enzyme exhibited relatively wide substrate specificity compared to D-aspartate oxidases reported so far. The pH and temperature optima were 7.5 - 8.0 and 35°C, respectively. The enzyme was stable at pH 6.0 - 9.0. About 75% of the enzyme activity was retained even after treating the enzyme at 50°C for 10 min. The enzyme activity was inhibited not by benzoate and tartrate, but 60% and 24% by fumarate and malonate, respectively.
基金Supported by Science and Technology Project of Guizhou Province[QKHN G(2007)4007]Project of Guizhou Academy of Agricultural Sciences[QNKH(Key)08017]
文摘[Objective] The paper was to explore the optimum dosage and application pattern of Trichoderma harzianum for controlling Potato Verticillium wilt. [ Method] Two trials, sowing seed tubers in bacterial manure, sowing seed tubers in bacterial manure + root irrigation after seedling emergence, were conducted in the paper. [Result] T.harzianum could effectively control potato early dying and promote potato growth, thereby increasing potato yield. The control effects of sowing tuber in 300 times of bacterial manure + root irrigation with 300 times of conidia suspension after seedling emergence were ideal ; the highest control effect and the highest saved yield loss were 72.60% and 33.33%, respectively. [ Conclusion] The paper provides reference for field application of T. harzianum.