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Arne Tronsmo - One of the best experts on this subject based on the ideXlab platform.
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effect of germination initiation on competitive capacity of Trichoderma Atroviride p1 conidia
Phytopathology, 2003Co-Authors: Linda Hjeljord, Arne TronsmoAbstract:ABSTRACT Trichoderma biocontrol isolates are most effective as highly concentrated inocula. Their antagonism to other fungi may be a result of pregermination respiration. In a nutrient-rich medium, almost all Trichoderma Atroviride P1 (P1) conidia initiated germination processes and increased respiration, even in dense suspensions. When 1 × 107 P1 conidia/ml were coinoculated with 1 × 105 Botrytis cinerea conidia/ml, dissolved oxygen fell to <1% within 2 h and the pathogen failed to germinate. More dilute P1 suspensions consumed oxygen slowly enough to allow coinoculated B. cinerea to germinate. On nutrient-poor media, fewer P1 conidia initiated germination. Oxygen consumption by the inoculum and inhibition of B. cinerea were enhanced when P1 conidia were nutrient activated before inoculation. Pregermination respiration also affected competitive capacity of the antagonist on solid substrates, where respiratory CO2 stimulated germination rate and initial colony growth. These parameters were directly correl...
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Effect of Germination Initiation on Competitive Capacity of Trichoderma Atroviride P1 Conidia.
Phytopathology, 2003Co-Authors: Linda Hjeljord, Arne TronsmoAbstract:ABSTRACT Trichoderma biocontrol isolates are most effective as highly concentrated inocula. Their antagonism to other fungi may be a result of pregermination respiration. In a nutrient-rich medium, almost all Trichoderma Atroviride P1 (P1) conidia initiated germination processes and increased respiration, even in dense suspensions. When 1 × 107 P1 conidia/ml were coinoculated with 1 × 105 Botrytis cinerea conidia/ml, dissolved oxygen fell to
Vincent G. H. Eijsink - One of the best experts on this subject based on the ideXlab platform.
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Molecular cloning, characterization, and expression studies of a novel chitinase gene (ech30) from the mycoparasite Trichoderma Atroviride strain P1
FEMS microbiology letters, 2006Co-Authors: Sonja Klemsdal, Jihong Clarke, Ingunn A. Hoell, Vincent G. H. Eijsink, May-bente BrurbergAbstract:We describe the cloning and characterization of a single copy gene from Trichoderma Atroviride P1 encoding a novel 30 kDa chitinase, Ech30. Ech30 is a family 18 chitinase showing low sequence similarity to other Trichoderma chitinases. Real-time quantitative RT-PCR studies revealed that expression of the ech30 gene was induced by the presence of Botrytis cinerea in plate confrontation assays, but hardly by chitin in liquid cultures. Studies of Ech30 purified from an Escherichia coli strain overexpressing the ech30 gene devoid of the leader sequence and a predicted intron, showed that the gene encodes an active chitinase, which, as expected for family 18 chitinases, is inhibited by allosamidin.
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Overexpression and characterization of a novel chitinase from Trichoderma Atroviride strain P1
Biochimica et biophysica acta, 2005Co-Authors: Ingunn A. Hoell, Sonja Klemsdal, Gustav Vaaje-kolstad, Svein J. Horn, Vincent G. H. EijsinkAbstract:We describe the overexpression and characterization of a new 30 kDa family 18 chitinase (Ech30) from Trichoderma Atroviride strain P1. Sequence alignments indicate that the active site architecture of Ech30 resembles that of endochitinases such as hevamine from the rubber tree (Hevea brasiliensis). The ech30 gene was overexpressed in Escherichia coli without its signal peptide and with an N-terminal His-tag. The enzyme was produced as inclusion bodies, from which active chitinase could be recovered using a simple refolding procedure. The enzyme displayed an acidic pH-optimum (pH 4.5-5.0), probably due to the presence of a conserved Asn residue near the catalytic glutamate, which is characteristic for acidic family 18 chitinases. Studies with oligomers of N-acetylglucosamine [(GlcNAc)(n)], 4-methylumbelliferyl (4-MU) labelled GlcNAc oligomers and beta-chitin reveal enzymatic properties typical of an endochitinase: 1) low activity towards short substrates (kinetic parameters for the hydrolysis of 4-MU-(GlcNAc)2 were K(m), 149+/-29 microM and k(cat), 0.0048+/-0.0005 s(-1)), and 2) production of relatively large amounts of trimers and tetramers during degradation of beta-chitin. Detailed studies with GlcNAc oligomers indicated that Ech30 has as many as seven subsites for sugar binding. As expected for a family 18 chitinase, catalysis proceeded with retention of the beta-anomeric configuration.
Linda Hjeljord - One of the best experts on this subject based on the ideXlab platform.
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effect of germination initiation on competitive capacity of Trichoderma Atroviride p1 conidia
Phytopathology, 2003Co-Authors: Linda Hjeljord, Arne TronsmoAbstract:ABSTRACT Trichoderma biocontrol isolates are most effective as highly concentrated inocula. Their antagonism to other fungi may be a result of pregermination respiration. In a nutrient-rich medium, almost all Trichoderma Atroviride P1 (P1) conidia initiated germination processes and increased respiration, even in dense suspensions. When 1 × 107 P1 conidia/ml were coinoculated with 1 × 105 Botrytis cinerea conidia/ml, dissolved oxygen fell to <1% within 2 h and the pathogen failed to germinate. More dilute P1 suspensions consumed oxygen slowly enough to allow coinoculated B. cinerea to germinate. On nutrient-poor media, fewer P1 conidia initiated germination. Oxygen consumption by the inoculum and inhibition of B. cinerea were enhanced when P1 conidia were nutrient activated before inoculation. Pregermination respiration also affected competitive capacity of the antagonist on solid substrates, where respiratory CO2 stimulated germination rate and initial colony growth. These parameters were directly correl...
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Effect of Germination Initiation on Competitive Capacity of Trichoderma Atroviride P1 Conidia.
Phytopathology, 2003Co-Authors: Linda Hjeljord, Arne TronsmoAbstract:ABSTRACT Trichoderma biocontrol isolates are most effective as highly concentrated inocula. Their antagonism to other fungi may be a result of pregermination respiration. In a nutrient-rich medium, almost all Trichoderma Atroviride P1 (P1) conidia initiated germination processes and increased respiration, even in dense suspensions. When 1 × 107 P1 conidia/ml were coinoculated with 1 × 105 Botrytis cinerea conidia/ml, dissolved oxygen fell to
Jie Chen - One of the best experts on this subject based on the ideXlab platform.
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Co-culture of Trichoderma Atroviride SG3403 and Bacillus subtilis 22 improves the production of antifungal secondary metabolites
Biological Control, 2020Co-Authors: Jia-quan Tang, Valliappan Karuppiah, Jie ChenAbstract:Abstract In this study, the co-cultivation of Trichoderma Atroviride SG3403 and Bacillus subtilis 22 was optimized for the production of antifungal metabolites. Response surface methodology was applied to establish a statistical model for optimizing the co-culture medium components and fermentation conditions. The results showed that the optimal co-culture parameters were 28 °C, 214 rpm, initial pH of 6.8 and a medium containing 10 g/l yeast powder and 27.6 g/l molasses. Under the optimal conditions, the fermented culture filtrate of the co-culture inhibited Fusarium graminearum by 54.22%. Furthermore, antifungal and plant growth promoting metabolites were increased in the fermented culture filtrate of co-culture compared with the monoculture. The increased production of specific antifungal and plant growth promoting components in the co-culture could enhance the biocontrol effect of Trichoderma and Bacillus, and the mixture provides an effective source for the development of bio-control agents.
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Biological control of southern corn leaf blight by Trichoderma Atroviride SG3403
Biocontrol Science and Technology, 2015Co-Authors: Meng Wang, Lili Fan, Gao Jinxin, Jie ChenAbstract:Trichoderma Atroviride SG3403 showed high biocontrol activity against southern corn leaf blight (SCLB; pathogen: Cochliobolus heterostrophus). T. Atroviride SG3403 could cause death of C. heterostrophus race O hypha on plates. Spraying T. Atroviride SG3403 conidia suspension over maize seedling leaves protected the corn from SCLB infection. Biocontrol effect lasted for 30 days in the field. Trichoderma strain was able to induce resistance response in corn leaves against pathogen infection. In corn leaves treated with T. Atroviride SG3403, the enzyme activities of phenylalanine ammonia lyase (PAL) and superoxide dismutase (SOD) reached the highest at 24 h, enzyme activity of catalase (CAT) reached the highest at 36 h after inoculation of pathogen C. heterostrophus race O. RNA expression levels of Pal, Sod and Cat (which synthesis enzyme PAL, SOD and CAT) were also upregulated and corresponded to the enzyme activity at the same time point. Enzyme activities and corresponding genes expression induced by Tric...
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Disruption of hex1 in Trichoderma Atroviride leads to loss of Woronin body and decreased tolerance to dichlorvos.
Biotechnology letters, 2013Co-Authors: Jun Tang, Xu Yuan, Shigang Gao, Wanjun Shi, Jie ChenAbstract:The tolerance of Trichoderma species to organophosphorus pesticides is necessary for their application in the bioremediation of pesticide-polluted environments. In some cases, such a requirement is also key to the synergistic use of these fungi with chemical pesticides, aiming to broaden the scope of control targets to include both plant pathogens and insect pests. However, the mechanism of Trichoderma tolerance of organophosphorus pesticides remains unclear. To address this, we have analyzed the function of the putative dichlorvos-tolerance gene hex1 by knocking it out. The hex1-deleted mutant showed loss of Woronin bodies and decreased tolerance to the organophosphate, dichlorvos. Moreover, HEX1 localizes at the septal plugs in mycelium which may be involved in controlling intracellular movement of dichlorvos. hex1 thus is involved the tolerance to dichlorvos and the formation of Woronin bodies in Trichoderma Atroviride.
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Conidia immobilization of T-DNA inserted Trichoderma Atroviride mutant AMT-28 with dichlorvos degradation ability and exploration of biodegradation mechanism
Bioresource technology, 2010Co-Authors: Wenliang Sun, Jie Chen, Jun Tang, Lixing Liu, Yunpeng Chen, Peng LiuAbstract:Abstract An immobilizing conidia approach was used to study the degradation ability of dichlorvos in Trichoderma Atroviride T-DNA insertional mutant AMT-28. Beads with 107 immobilized conidia per 100 mL of Na-alginate solution exhibited the highest degradation abilities. The immobilized conidia showed enhanced degradation abilities compared with immobilized or freely suspended mycelia. The immobilized cells kept good storage capacity and reusability. Dichlorvos was confirmed to be completely removed by mycelia of AMT-28 within 7 days using HPLC analysis. The dichlorvos degradation rates in auxotrophic Burk media varied and were significantly affected by nitrogen sources. There was no detectable biosorption and the removal of dichlorvos in AMT-28 was primarily attributed to a kind of Biomineralization process.
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Improved degradation of organophosphate dichlorvos by Trichoderma Atroviride transformants generated by restriction enzyme-mediated integration (REMI).
Bioresource technology, 2008Co-Authors: Jun Tang, Lixing Liu, Yunpeng Chen, Jie ChenAbstract:Abstract A simple technique, REMI (restriction enzyme-mediated integration), was used to construct transformants of Trichoderma Atroviride with improved capability of degrading organophosphate pesticide dichlorvos. Linearized DNA of plasmid pV2 bearing the hygromycin B phosphotransferase ( hph ) gene was inserted into chromosomes of wild strain T23 and transformation was confirmed by PCR and Southern blot analysis, respectively. Of 247 transformants, 76% showed improved dichlorvos degradation ability as compared to the parent strain T23 based on the least significant difference (LSD) test at p = 0.01. Among them, 8 transformants exhibited 30% higher in degradation rate than the parent isolate. The highest dichlorvos degradation rate of the transformants was up to 96%. This study provided an effective approach for improving organophosphate pesticide-degrading capability of T. Atroviride .
Ingunn A. Hoell - One of the best experts on this subject based on the ideXlab platform.
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Molecular cloning, characterization, and expression studies of a novel chitinase gene (ech30) from the mycoparasite Trichoderma Atroviride strain P1
FEMS microbiology letters, 2006Co-Authors: Sonja Klemsdal, Jihong Clarke, Ingunn A. Hoell, Vincent G. H. Eijsink, May-bente BrurbergAbstract:We describe the cloning and characterization of a single copy gene from Trichoderma Atroviride P1 encoding a novel 30 kDa chitinase, Ech30. Ech30 is a family 18 chitinase showing low sequence similarity to other Trichoderma chitinases. Real-time quantitative RT-PCR studies revealed that expression of the ech30 gene was induced by the presence of Botrytis cinerea in plate confrontation assays, but hardly by chitin in liquid cultures. Studies of Ech30 purified from an Escherichia coli strain overexpressing the ech30 gene devoid of the leader sequence and a predicted intron, showed that the gene encodes an active chitinase, which, as expected for family 18 chitinases, is inhibited by allosamidin.
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Overexpression and characterization of a novel chitinase from Trichoderma Atroviride strain P1
Biochimica et biophysica acta, 2005Co-Authors: Ingunn A. Hoell, Sonja Klemsdal, Gustav Vaaje-kolstad, Svein J. Horn, Vincent G. H. EijsinkAbstract:We describe the overexpression and characterization of a new 30 kDa family 18 chitinase (Ech30) from Trichoderma Atroviride strain P1. Sequence alignments indicate that the active site architecture of Ech30 resembles that of endochitinases such as hevamine from the rubber tree (Hevea brasiliensis). The ech30 gene was overexpressed in Escherichia coli without its signal peptide and with an N-terminal His-tag. The enzyme was produced as inclusion bodies, from which active chitinase could be recovered using a simple refolding procedure. The enzyme displayed an acidic pH-optimum (pH 4.5-5.0), probably due to the presence of a conserved Asn residue near the catalytic glutamate, which is characteristic for acidic family 18 chitinases. Studies with oligomers of N-acetylglucosamine [(GlcNAc)(n)], 4-methylumbelliferyl (4-MU) labelled GlcNAc oligomers and beta-chitin reveal enzymatic properties typical of an endochitinase: 1) low activity towards short substrates (kinetic parameters for the hydrolysis of 4-MU-(GlcNAc)2 were K(m), 149+/-29 microM and k(cat), 0.0048+/-0.0005 s(-1)), and 2) production of relatively large amounts of trimers and tetramers during degradation of beta-chitin. Detailed studies with GlcNAc oligomers indicated that Ech30 has as many as seven subsites for sugar binding. As expected for a family 18 chitinase, catalysis proceeded with retention of the beta-anomeric configuration.
