Showing papers on "Trichoderma harzianum published in 2000"
TL;DR: In this paper, a commercial biocontrol agent (BCA) was applied to the roots of cucumber plants to suppress enzymes of B. cinerea, such as pectinases, cutinase, glucanase and chitinase.
445 citations
TL;DR: Correlation between different genotypes and potential biocontrol activity was studied under dual culturing of 17 BCAs in the presence of the phytopathogenic fungi Phoma betae, Rosellinia necatrix, Botrytis cinerea, andFusarium oxysporum f.
Abstract: The most common biological control agents (BCAs) of the genus Trichoderma have been reported to be strains of Trichoderma virens, T. harzianum, and T. viride. Since Trichoderma BCAs use different mechanisms of biocontrol, it is very important to explore the synergistic effects expressed by different genotypes for their practical use in agriculture. Characterization of 16 biocontrol strains, previously identified as "Trichoderma harzianum" Rifai and one biocontrol strain recognized as T. viride, was carried out using several molecular techniques. A certain degree of polymorphism was detected in hybridizations using a probe of mitochondrial DNA. Sequencing of internal transcribed spacers 1 and 2 (ITS1 and ITS2) revealed three different ITS lengths and four different sequence types. Phylogenetic analysis based on ITS1 sequences, including type strains of different species, clustered the 17 biocontrol strains into four groups: T. harzianum-T. inhamatum complex, T. longibrachiatum, T. asperellum, and T. atroviride-T. koningii complex. ITS2 sequences were also useful for locating the biocontrol strains in T. atroviride within the complex T. atroviride-T. koningii. None of the biocontrol strains studied corresponded to biotypes Th2 or Th4 of T. harzianum, which cause mushroom green mold. Correlation between different genotypes and potential biocontrol activity was studied under dual culturing of 17 BCAs in the presence of the phytopathogenic fungi Phoma betae, Rosellinia necatrix, Botrytis cinerea, and Fusarium oxysporum f. sp. dianthi in three different media.
300 citations
TL;DR: It is suggested that Trichoderma’'s association with roots reduce root disease through activation of the plant’s defence response throughactivation of the plants’ defence response.
299 citations
TL;DR: There was a significant negative correlation between the level of endochitinase production and both the amount of disease and plant growth of apple by transformation with genes encoding chitinolytic enzymes from the bio-control organism Trichoderma harzianum.
Abstract: The goal of this research was to improve scab resistance of apple by transformation with genes encoding chitinolytic enzymes from the bio-control organism Trichoderma harzianum. The endochitinase gene, as cDNA and genomic clones, was transferred into apple cv. Marshall McIntosh by Agrobacterium-transformation. A total of 15 lines were identified as transgenic by NPTII enzyme-linked immunosorbent assay and polymerase chain reaction and confirmed by Southern analysis. Substantial differences in endochitinase activity were detected among different lines by enzymatic assay and western analysis. Eight lines propagated as grafted and own-rooted plants were inoculated with Venturia inaequalis. Six of these transgenic lines expressing endochitinase were more resistant than nontransformed cv. Marshall McIntosh. Disease severity compared with cv. Marshall McIntosh was reduced by 0 to 99.7% (number of lesions), 0 to 90% (percentage of leaf area infected), and 1 to 56% (conidia recovered) in the transgenic lines tested. Endochitinase also had negative effects on the growth of both inoculated and uninoculated plants. There was a significant negative correlation between the level of endochitinase production and both the amount of disease and plant growth.
225 citations
TL;DR: PCR-DGGE analysis of DNA obtained from the silt loam soil treated with dibenzothiophene-containing petrol showed the progressive selection of specific fungal bands over time, whereas this selection was not observed in untreated soil microcosms.
209 citations
TL;DR: The effect of pepper seed and root treatments with Trichoderma harzianum spores on necrosis caused in stems by Phytophthora capsici inoculation and on the course of capsidiol accumulation in the inoculated sites were studied, suggesting a systemic defense response against P. capsici in the upper part of the plant.
Abstract: The effect of pepper seed and root treatments with Trichoderma harzianum spores on necrosis caused in stems by Phytophthora capsici inoculation and on the course of capsidiol accumulation in the inoculated sites were studied. The results indicate that seed treatments significantly reduced stem necrosis, which fell by nearly a half compared with the values observed in plants grown from non-treated seeds. Necrosis was also reduced in plants whose roots were drenched with various doses of T. harzianum spores, although the extent of necrosis was not correlated with the dose used. Attempted isolation of P. capsici and T. harzianum from the zones immediately contiguous with the necrotic zones revealed the presence of the former but not of the latter, suggesting that there was no direct contact between them in the zones of isolation, which means that there was no competition for space. The percentage of P. capsici isolated 9 days after inoculation was greater in non-treated inoculated plants than in treated inoculated plants. These results suggest that T. harzianum, introduced into the subterranean part of the plant, induces a systemic defense response against P. capsici in the upper part of the plant. Analysis of capsidiol in the stems of treated inoculated plants by the end of the sixth day after inoculation, revealed that its concentration was more than seven-fold greater than in non-treated and inoculated plants, while after 9 days, the concentration of capsidiol decreased in the treated inoculated plants and increased in the non-treated inoculated plants. The high concentration of capsidiol detected in treated and inoculated stems after 6 days might be one of the contributing factors, but not necessarily the main factor, in delaying lesion development in the stems of pepper plants.
141 citations
TL;DR: Bee delivery of T. harzianum delivered by bumble bees or honey bees provided better Botrytis control than that applied as a spray, indicating that the use of some commercial fungicides at bloom may impact pollination and yield.
133 citations
TL;DR: It is shown that cellophane membranes are permeable to proteins up to at least 90 kDa in size but that dialysis membranes are not, which is consistent with enzyme diffusion from T. atroviride to R. solani generating the trigger of ech42 gene expression.
Abstract: A plate confrontation experiment is commonly used to study the mechanism by which Trichoderma spp. antagonize and parasitize other fungi. Previous work with chitinase gene expression (ech42) during the precontact period of this process in which cellophane and dialysis membranes separated Trichoderma harzianum and its host Rhizoctonia solani resulted in essentially opposite results. Here, we show that cellophane membranes are permeable to proteins up to at least 90 kDa in size but that dialysis membranes are not. ech42 was expressed during the precontact stage of the confrontation between Trichoderma atroviride and its host only if the cellophane was placed between the two fungi. These results are consistent with enzyme diffusion from T. atroviride to R. solani generating the trigger of ech42 gene expression.
131 citations
Journal Article•
130 citations
TL;DR: Nine fungi which were performant for pyrene degradation, nine were not yet reported in the literature and showed a real value for PAH remediation.
121 citations
TL;DR: The results suggest that cotransformation with GFP and GUS can provide a valuable tool for the detection and monitoring of specific strains of T. harzianum released into the soil.
Abstract: Trichoderma harzianum was cotransformed with genes encoding green fluorescent protein (GFP), beta-glucuronidase (GUS), and hygromycin B (hygB) resistance, using polyethylene glycol-mediated transformation. One cotransformant (ThzID1-M3) was mitotically stable for 6 months despite successive subculturing without selection pressure. ThzID1-M3 morphology was similar to that of the wild type; however, the mycelial growth rate on agar was reduced. ThzID1-M3 was formed into calcium alginate pellets and placed onto buried glass slides in a nonsterile soil, and its ability to grow, sporulate, and colonize sclerotia of Sclerotinia sclerotiorum was compared with that of the wild-type strain. Wild-type and transformant strains both colonized sclerotia at levels above those of indigenous Trichoderma spp. in untreated controls. There were no significant differences in colonization levels between wild-type and cotransformant strains; however, the presence of the GFP and GUS marker genes permitted differentiation of introduced Trichoderma from indigenous strains. GFP activity was a useful tool for nondestructive monitoring of the hyphal growth of the transformant in a natural soil. The green color of cotransformant hyphae was clearly visible with a UV epifluorescence microscope, while indigenous fungi in the same samples were barely visible. Green-fluorescing conidiophores and conidia were observed within the first 3 days of incubation in soil, and this was followed by the formation of terminal and intercalary chlamydospores and subsequent disintegration of older hyphal segments. Addition of 5-bromo-4-chloro-3-indolyl-beta-D-glucuronic acid (X-Gluc) substrate to recovered glass slides confirmed the activity of GUS as well as GFP in soil. Our results suggest that cotransformation with GFP and GUS can provide a valuable tool for the detection and monitoring of specific strains of T. harzianum released into the soil.
TL;DR: The addition of JMS Stylet-Oil did not contribute to the control of the above mentioned diseases achieved by T39, and the effect of T39 on diseases of greenhouse crops was demonstrated.
Abstract: Isolate T39 of Trichoderma harzianum (TRICHODEX) is a commercial biocontrol agent. It controls Botrytis cinerea (grey mould) in greenhouse crops and in vineyards, Sclerotinia sclerotiorum (white mould) in various greenhouse and field crops, Cladosporium fulvum (leaf mould) in tomato, and the powdery mildews Sphaerotheca fusca in cucurbits and Leveillula taurica in pepper. T. harzianum T39 was applied in vineyards and greenhouses as part of grey mould management programmes in alternation with chemical fungicides. In the present study, the effect of T39 on diseases of greenhouse crops was demonstrated. The biocontrol agent was applied in formulations containing two concentrations of the active ingredient, or in the presence of oil in cucumber and tomato greenhouses. Suppression of B. cinerea , C. fulvum and S. sclerotiorum was similar when T39 was applied at final active ingredient rates of 0.2 or 0.4 g l -1 , except for one sampling date in one experiment. The addition of JMS Stylet-Oil did not contribute ...
TL;DR: Nucleotide sequence analysis shows that Trichoderma harzianum and Penicillium purpurogenum α1,3-glucanases (mutanases) have homologous primary structures, and the catalytic domains and the binding domains were assigned to a new family of glycoside hydrolases and to anew family of carbohydrate-binding domains, respectively.
TL;DR: T. virens DAR 74290 increased the survival of tomato seedlings inoculated with the pathogen, and both this isolate and Trichodex decreased the severity of disease on tomato.
Abstract: Trichoderma harzianum isolate T39 and T. virens isolate DAR 74290 were evaluated as potential biological agents for control of pink rot of potato and root and stem rot of tomato caused by Phytophthora erythroseptica. Cell-free metabolites of T. virens DAR 74290 completely inhibited growth of P. erythroseptica in vitro and appeared to be fungicidal. T. virens DAR 74290 and Trichodex, a commercial formulation of T. harzianum T39, were tested for their ability to protect potato and tomato plants from disease caused by P. erythroseptica in glasshouse experiments. Trichodex and T. virens DAR 74290, alone and combined, reduced disease severity in shoots and roots of potatoes 10 weeks after inoculation with the pathogen. The yield of potatoes from plants treated with P. erythroseptica and T. virens DAR 74290 (mean of 12.9 g fresh weight/pot) was significantly greater than in controls inoculated with the pathogen alone (mean of 2.1 g/pot). Treatment with Trichodex alone increased the yield of tubers compared to the uninoculated controls. T. virens DAR 74290 increased the survival of tomato seedlings inoculated with the pathogen, and both this isolate and Trichodex decreased the severity of disease on tomato.
TL;DR: Trichoderma harzianum (TrH 40) treatment, while reducing the occurrence of the three postharvest diseases, also retained the overall quality and color of the fruits.
Abstract: Trichoderma harzianum (TrH 40) isolated from soil samples from rambutan orchards (Nephelium lappaceum) had antagonistic effects against three postharvest pathogens of rambutan:Botryodiplodia theobromae, Colletotrichum gloeosporioides andGliocephalotrichum microchlamydosporum, causative fungi of stem end rot, anthracnose and brown spot, respectively. The effects were due to both antibiosis and mycoparasitism.T. harzianum (TrH 40) treatment, while reducing the occurrence of the three postharvest diseases, also retained the overall quality and color of the fruits.
TL;DR: Pea seeds treated for 24 h with the dilution of 10 −2 of Trichoderma inoculant extracts resulted in the most rapid plant growth and highest phenolic content of pea seedlings.
TL;DR: The results demonstrate the potential of G. virens for increasing growth when used to inoculate blueberry plants in the nursery or at transplanting.
Abstract: Additional index words. rhizobacteria, Pseudomonas corrugata , Bacillus pumilus, Pseudomonas fluorescens, Gliocladium virens, Trichoderma harzianum, Vaccinium corymbosum Abstract. The highbush blueberry cultivar Bluecrop was inoculated with potential plant growth-promoting (PGPR) candidates, including bacterial inoculants Pseudomonas fluorescens (Migula) (strains Pf 5, PRA 25, 105, or 101), Bacillus pumilus (Mayer and Gottheil) (strain T4), Pseudomonas corrugata (Roberts and Scarlett) (strain 114), and fungal isolates Gliocladium virens (Miller et al., Von Arx) (strain Gl.21) and Trichoderma harzianum (Rifai) (strain T 22). Addition of G. virens to pasteurized soil increased leaf area and the number of leaves produced in a 4-month growth period, as well as shoot content of P, Zn and Cu in 1997. Treatment with P. fluorescens Pf 5 increased leaf area and stem diameter. In nonpasteurized soil, plants inoculated with G. virens had greater leaf area, stem diameter, shoot and root dry weight, and more leaves per plant. These results demonstrate the potential of G. virens for increasing growth when used to inoculate blueberry plants in the nursery or at transplanting.
TL;DR: This is the first report of 3-(1-hexenyl)-5-methyl-2-(5H)-furanone produced by a bacterium, and has structural similarity to other antifungal furanones produced by actinomycetes, fungi, and higher plants.
Abstract: Pseudomonas aureofaciens (= P. chlororaphis) strain 63-28 is a biocontrol agent active against many soil-borne fungal plant pathogens and shows antifungal activity in culture assays. 3-(1-Hexenyl)-5-methyl-2-(5H)furanone was isolated from culture filtrates of this bacterium. The purified furanone showed antifungal activity against Pythium ultimum, Fusarium solani, Fusarium oxysporum, and Thielaviopsis basicola. The ED50S for spore germination of these fungi were 45, 54, 56, and 25 μg/ml, respectively. The compound also inhibited the germ tube growth of Rhizoctonia solani growing from microsclerotia, with an ED50 of 61 μg/ml. The compound is the reduced form of furanones previously described from this bacterium: 3-(1-hexenyl)-5-hydroxy-5-methyl-2-(5H)-furanone and 3-(1-hexenyl)-5-hydroxymethyl-2-(5H)-furanone. This volatile antifungal furanone has structural similarity to other antifungal furanones produced by actinomycetes (Streptomyces spp.), fungi (Trichoderma harzianum), and higher plants (Pulsatilla and Ranuculus spp.). This is the first report of 3-(1-hexenyl)-5-methyl-2-(5H)-furanone produced by a bacterium.
TL;DR: It is concluded that not only were the Trichoderma strains tested unable to germinate as quickly as B. cinerea and M. piriformis at the ambient temperatures of the greenhouse, but also that the commercially formulated conidia lost the capacity to germine on and effectively colonize nutrient-poor natural substrates.
TL;DR: The results suggest that each β-1,3-glucanase produced by T. harzianum is different and is probably encoded by different genes.
Abstract: A β-1,3-glucanase, from culture filtrates of Trichoderma harzianum, was purified in sequential steps by gel filtration, hydrophobic interaction and ion exchange chromatography. A typical procedure provided 69-fold purification with 0.32% yield. The molecular mass of the protein was found to be approximately 29 kDa, as estimated by SDS-PAGE on a 10% slab gel. The KM and Vmax values for β-1,3-glucanase, using laminarin as substrate, were 1.72 mg ml−1 and 3.10 U ml−1, respectively. The pH optimum for the enzyme was pH 4.4 and maximum activity was obtained at 50°C. The enzyme was strongly inhibited by HgCl2 and SDS. These results suggest that each β-1,3-glucanase produced by T. harzianum is different and is probably encoded by different genes.
TL;DR: A Trichoderma harzianum isolate, which was able to antagonize in field the phytopathogen Crinipellis perniciosa, the causal agent of witches' broom disease of cocoa, produces several hydrolytic enzymes.
Abstract: A Trichoderma harzianum isolate (1051), which was able to antagonize in field the phytopathogen Crinipellis perniciosa, the causal agent of witches' broom disease of cocoa, produces several hydrolytic enzymes. A chitinase, with molecular mass of about 37 kDA, which was secreted by the Trichoderma in the culture medium containing chitin, was partially purified by gel filtration followed by hydrophobic chromatography. The optimal pH and temperature for chitin hydrolysis by the partially purified enzyme were 4.0 and 37 °C, respectively. Chitobiose, laminarin, cellulosic substrates including aryl-glucosides, xylan, starch and β-galactomannan were not hydrolysed by the enzyme. Remarkably, the partially purified enzyme drastically affected the cell wall of the phytopathogen C. perniciosa in vitro.
TL;DR: In this paper, the authors compared the production of 6-pentyl-[alpha]-pyrone (6-PP) by Trichoderma harzianum in liquid and in solid state cultivation (LC and SSC).
TL;DR: The results suggest the possibility of using mutants with improved xerotolerance for biocontrol purposes in soils with lower water potentials, and nearly linear correlation was found between water potential and colony growth rate at both 25°C and 10°C.
Abstract: The influence of water potential on linear mycelial growth, secretion, and the in vitro activities of enzymes β-glucosidase, cellobiohydrolase, β-xylosidase, exochitinase, and chymotrypsin of Trichoderma harzianum strain T66 was studied at different temperatures. Nearly linear correlation was found between water potential and colony growth rate at both 25°C and 10°C, with higher growth rates at the higher temperature and higher water potentials. The amounts of enzyme secretion depended on the water potential and not on the quality of salt (NaCl or KCl) used as osmoticum. Enzyme activities were significantly affected by water potential. Significant enzyme activities were measured for most of the enzymes even at −14.800 megapascal (MPa), which is below the water potential where mycelial growth ceased. These results suggest the possibility of using mutants with improved xerotolerance for biocontrol purposes in soils with lower water potentials.
TL;DR: Soil solarization provided the best control of garlic white rot, bringing soil populations of S. cepivorum to negligible levels, but lower levels of disease control were obtained when selected isolates of Trichoderma harzianum and Bacillus subtilis were applied to the soil and cloves respectively.
Abstract: Treatment of garlic cloves with tebuconazole (at 1 ml of Folicur 25% l−1) achieved a significant reduction in the rate of disease progress and the final incidence of plant death by Sclerotium cepivorum: garlic yields were improved. Although soil solarization provided the best control of garlic white rot, bringing soil populations of S. cepivorum to negligible levels, similar levels of disease control and garlic yields were achieved when tebuconazole was sprayed to stem bases of plants grown from cloves also treated with tebuconazole. This double treatment almost doubled the yield compared with untreated plants and significantly increased bulb quality under high disease pressure conditions. Soil solarization was also highly effective in a second consecutive crop of garlic, with significant improvements in yield and garlic quality. In contrast, lower levels of disease control were obtained when selected isolates of Trichoderma harzianum and Bacillus subtilis were applied to the soil and cloves respectively.
TL;DR: Disease control declined as Trial 2 progressed with over 95% of the plants infected in all treatments at trial completion, but strategies for field application of the best biological control agents for control of onion white rot are discussed.
Abstract: The fungal species Chaetomium globosum, Coniothyrium minitans, Trichoderma harzianum, T. koningii, and T. virens were confirmed as antagonists of Sclerotium cepivorum, the causal agent of onion white rot in two glasshouse trials. In Trial 1, all fungal treatments afforded disease control equivalent to the fungicide procymidone (1 g a.i./ 100 g seed) when applied to the soil as a soil additive (sand:bran:fungal mix, 1:1:2) at the time of planting. Applications of T. harzianum (C52) and T. koningii (C62) significantly reduced disease incidence from 39.8% in the control to 7.7 and 5.4%, respectively. When treatments were applied 2 weeks before planting, only T. harzianum (C52) gave disease control equivalent to the fungicide. In Trial 2, disease incidence was significantly less when T. harzianum (C52, D73) and T. virens (GV4) were applied as soil additives at planting (34, 40, and 43.1 %, respectively) compared with that in the control treatment (66.5%) 8 weeks after planting. However, disease contr...
TL;DR: Maximal overproduction of BGN16.2 albeit pure was achieved in buffered medium, where pH-induced aspartyl proteases were absent or when some nitrogen sources, such as yeast extract, peptone or casein were substrate for these proteases.
TL;DR: Th2 mycelium flourished in compost unin- oculated or inoculated with A. bisporus, but myceli- um of the button mushroom is required for intensive sporulation.
Abstract: Trichoderma harzianum biotype Th2, re- sponsible for green mold disease, appeared in the North of France by the end of 1997. Cocultures of Agaricus bisporus with four French Th2 isolates and three less aggressive Trichoderma species were per- formed in conventional compost to further our un- derstanding of how Trichoderma Th2 establishes and competes with the button mushroom. Spore germi- nation of Th2 isolates was little affected by A. bisporus mycelium while that of other species was strongly in- hibited. Th2 mycelium flourished in compost unin- oculated or inoculated with A. bisporus, but myceli- um of the button mushroom is required for intensive sporulation. No fungistatic effect of the mycelium of Trichoderma on A. bisporus was observed in compost, but when Th2 produced spores, toxicity toward A. bisporus was detected. A simultaneous growth of A. bisporus and Th2 was observed before the mycelium of Agaricus stimulated the Th2 sporulation. As soon as sporulation occurred the mycelial growth of A. bis- porus was dramatically reduced and typical green
Journal Article•
TL;DR: Three isolates of Trichoderma harzianum, viz.
Abstract: In dual culture of 11 isolates of Trichoderma harzianum, three isolates, viz. T8, T10 and T2, were effective against Sclerotium rolfsii [Corticium rolfsii], the causal agent of stem rot of groundnut, and they overgrew the pathogen up to 92, 85 and 79%, respectively, in vitro. T8 and T10 isolates reduced stem rot incidence significantly when delivered as seed dressing or soil application in pot trials. Disease reduction through seed dressing was 33-50% over control and through direct soil application it was up to 72-83%. Spores of T8 and T10 isolates showed better longevity after 13 weeks (1.3 x 103 cfu/seed) and up to 15 weeks (1.0 x 104 cfu/seed), respectively, when the seeds coated with spores were dipped in 2% carboxy methyl cellulose (CMC) andpelleted with bentonite at 25 g/kg seed. The maximum population was recorded at 30 day after storing (T8 = 3.5 x 106 and T10 = 20.2 x 106). On seed coated with Trichoderma spores infused with 2% CMC and then pelleted with a mixture of Jalshakti (a water-absorbing polymer) at 100 g/kg and bentonite at 25 g/kg seed, Trichoderma remained viable only up to 11 weeks. The spores remained viable only up to 9 weeks of storage at room temperature on seeds when the seeds were coated with biocontrol agent by rolling seeds on a colony of Trichoderma in Petri dishes.
TL;DR: Organic mulches colonized with microbial biocontrol agents, termed bioenhanced mulches, were tested for their ability to reduce Phytophthora root rot of avocado and Sudangrass and a coarse yardwaste were found to be better substrates than a fine Yardwaste, woodwaste or rice hulls for biocOntrol agents propagules production.
TL;DR: Blue light seems to warn the organism against the harmful effects of short wavelengths, inducing phr1 expression and sporulation by pathways that are, at least in part, distinct.
Abstract: Blue light and development regulate the expression of the phr1 gene of the filamentous fungus Trichoderma harzianum. The predicted product of phr1, the DNA repair enzyme photolyase, is likely to help protect Trichoderma, which grows in the soil as a mycoparasite or saprophyte, from damage upon emergence and exposure to ultraviolet-c. phr1 is transiently expressed in mycelium and conidiophores after illumination. phr1 mRNA also accumulates in conidiophores during development and spore maturation. As no other genes displaying rapid, direct light regulation have been described previously in this organism, we have characterized the fluence and time dependence of phr1 induction, and its relation to sporulation and photoreactivation. Induction is transient following a pulse, and, with slower decay, in continuous light. This implies that the photoreceptor, transducers or response are capable of adaptation. About two-fold more light is required to induce phr1 than conidiation, but this difference is modest, so both responses could use the same or similar chromophore. Adenosine 3':5'-cyclic monophosphate bypasses the requirement for light for sporulation, while atropine prevents sporulation even after photoinduction. Light regulation of phr1, however, is indifferent to both these effectors. Induction of photolyase expression behaves as a direct, rapid response to light, independent of the induction of sporulation. Indeed, illumination of mature spores increases their capacity for photoreactivation. Blue light seems to warn the organism against the harmful effects of short wave-lengths, inducing phr1 expression and sporulation by pathways that are, at least in part, distinct.