Effect of pH and Temperature on Enzyme Activity of Chitosanase Produced Under Solid Stated Fermentation by <Emphasis Type="Italic">Trichoderma</Emphasis> spp<Emphasis Type="Italic">.</Emphasis>

Trichoderma strains were extensively studied as biocontrol agents due to their ability of producing hydrolytic enzymes, which are considered key enzymes because they attack the insect exoskeleton allowing the fungi infection. The present work aimed to evaluate the ability of chitosanase production by four Trichoderma strains (T. harzianum, T. koningii, T. viride and T. polysporum) under solid stated fermentation and to evaluate the effect of pH and temperature on enzyme activity. pH strongly affected the enzyme activity from all tested strains. Chitosanase from T. harzianum and T. viride presented optimum activity at pH 5.0 and chitosanase from T. koningii and T. polysporum presented optimum activity at pH 5.5. Temperature in the range of 40–50°C did not affect enzyme activity. T. polysporum was found as the most promising strain to produce chitosanase with maximal enzyme activity of about 1.4 IU/gds, followed by T. viride (~1.2 IU/gds) and T. harzianum (1.06 IU/gds).     

Specific PCR assays for the detection of <Emphasis Type="Italic">Trichoderma harzianum</Emphasis> causing green mold disease during mushroom cultivation

We have developed a polymerase chain reaction (PCR)-based detection method for Trichoderma harzianum, which causes green mold disease in mushroom cultivation fields and facilities. Based on the sequence data of the internal transcribed spacer (ITS) region of T. harzianum strains and several other species, six primers consisting of three forward and three reverse primers were designed. Among the nine possible combinations of these primers, PCR with the pair THITS-F2 and THITS-R3 distinguished most T. harzianum strains from other Trichoderma species. The optimal annealing temperature for detection of T. harzianum strains was from 62° to 63°C with this primer combination. We designed new primers derived from THITS-F2 and THITS-R3. Annealing temperatures to detect T. harzianum ranged from 64° to 67°C using the new primers. The detection limit of T. harzianum DNA was 50 fg by nested PCR with THITS-F1 and LR1-1 for the first PCR and the new primers for the second PCR. T. harzianum was readily detectable in contaminated cultures of Lentinula edodes by this method.     

The calanoid copepods of the Nile system

At least 11 or 12 calanoid taxa occur in the Nile system. One species is typical of the river and of Lake Chad (Th. galebi); two are restricted to Lake Victoria (Th. galeboides, T. stuhlmanni), but both might be only subspecies to more widespread species. One is restricted to Lakes Edward and George (T. worthingtoni) but is a little known species. No calanoids are on record from Lakes Albert and Kyoga, while the species reported from Lake Turkana (T. banforanus) is out of range, and almost certainly represents an erroneous record. Among the remaining species, four are East-African, ranging from the southern tip of the continent to the Ethiopian plateau and the Nile valley (P. schultzei, Th. mixtus, T. kraepelini, T. cf orientalis), while two are Sahelian species that span Africa from east to west (M. mauretanicus, T. processifer et ssp.).Two new synonyms are introduced. One new subspecies (T. processifier friedae) is described from the Ethiopian plateau. It is suggested that Tropodiaptomus orientalis (Brady, 1886), the type species of its genus, should not be considered a nomen dubium, but should be redescribed on its type female(s) and on topotypical males from Sri Lanka.     

<i>Trichoderma</i>-Induced Improvement in Growth,Photosynthetic Pigments,Proline, and Glutathione Levels in <i>Cucurbita pepo</i> Seedlings under Salt Stress

Salt stress is one of the major abiotic stress in plants. However, traditional approaches are not always efficient in conferring salt tolerance. Experiments were conducted to understand the role of Trichoderma spp. (T. harzianum and T. viride) in growth, chlorophyll (Chl) synthesis, and proline accumulation of C. pepo exposed to salinity stress. There were three salt stress (50, 100, and 150 mM NaCl) lavels and three different Trichoderma inoculation viz. T. harzianum, T. viride, and T. harzianum + T. viride. Salt stress significantly declined the growth in terms of the shoot and root lengths; however, it was improved by the inoculation of Trichoderma spp. C. pepo inoculated with Trichoderma exhibited increased synthesis of pigments like chl a, chl b, carotenoids, and anthocyanins under normal conditions. It was interesting to observe that such positive effects were maintained under salt-stressed conditions, as reflected by the amelioration of the salinity-mediated decline in growth, physiology and antioxidant defense. The inoculation of Trichoderma spp. enhanced the synthesis of proline, glutathione, proteins and increased the relative water content. In addition, Trichoderma inoculation increased membrane stability and reduced the generation of hydrogen peroxide. Therefore, Trichoderma spp. can be exploited either individually or in combination to enhance the growth and physiology of C. pepo under saline conditions.     

Control of the bean rust fungus <Emphasis Type="Italic">Uromyces appendiculatus</Emphasis> by means of <Emphasis Type="Italic">Trichoderma harzianum</Emphasis>: leaf disc assays on the antibiotic effect of spore suspensions and culture filtrates

Several species of the fungal genus Trichoderma act as antagonists of other fungi. A number of strains from the Trichoderma species T. harzianum Rifai are used as biological control agents for the control of soilborne as well as foliar plant pathogens. Six T. harzianum strains, five of them isolated from commercial preparations, were evaluated for their capability to control the bean rust fungus Uromyces appendiculatus (Pers. ex Pers.) Unger. Different kinds of leaf disc assays were performed with conidial spore suspensions and sterile culture filtrates of the T. harzianum strains. Great differences were observed concerning the efficacy of the Trichoderma strains to reduce the number of the uredial pustules developing after rust inoculation which followed the application of the particular Trichoderma strains. Efficacy values ranged from 1 to over 50%. Increasing spore or culture filtrate concentrations of the two most effective isolates T12 and T_U led to decreases in the number of developing uredial pustules. Culture filtrate applications had a protective but no curative effect. T12 spore suspensions maintained their disease reducing activity even when autoclaved. This and some other evidence for an antibiotic interaction between T. harzianum and U. appendiculatus are discussed. Handling Editor: Reijo Karjalainen.     

<Emphasis Type="Italic">In vitro</Emphasis> biocontrol analysis of <Emphasis Type="Italic">Alternaria alternata</Emphasis> (Fr.) Keissler under different environmental conditions

The species Trichoderma harzianum was analyzed as possible biocontrol agent of Alternaria alternata under different environmental conditions (water activity and temperature). The strains were analyzed macroscopically to obtain the Index of Dominance. The analysis was completed using two microscopic techniques. T. harzianum showed dominance on contact over A. alternata at all testing temperatures and water activities tested except at 0.95 a _w and 15 °C, at which T. harzianum inhibited A. alternata at a distance. Biocontrol was governed by different mechanisms such as competition for space and nutrients, mycoparasitism, and possible antibiosis. Temperature and water activity significantly influenced fungal growth rate.     

Effect of antimicrobial activity of Melaleuca alternifolia essential oil on antagonistic potential of Pleurotus species against Trichoderma harzianum in dual culture

Melaleuca alternifolia (tea tree) essential oil was investigated for its “in vitro” ability to control Trichoderma harzianum, a fungal contaminant that causes extensive losses in the cultivation of Pleurotus species. The antifungal activity of M. alternifolia essential oil and antagonist activities between Pleurotus species against three T. harzianum strains were studied in dual-culture experiments on an agar-based medium in which different concentrations of essential oil were incorporated. M. alternifolia essential oil at a concentration of 0.625 μL/mL, inhibited T. harzianum mycelial growth by 5.9–9.0%, depending on the strain. At the same concentrations P. ferulae and P. nebrodensis stimulated mycelial growth by 5.2–8.1%. All strains of T. harzianum were antagonistic to the Pleurotus species in the control. When essential oil was added to the substrate cultural, the antagonistic activity of T. harzianum against the Pleurotus species was weak (0.0625 μL of essential oil) or non-existent (0.125 μL of essential oil). M. alternifolia essential oil could be an alternative to the synthetic chemicals that are currently used to prevent and control T. harzianum in mushroom cultivation.     

Effect of pH and temperature on the global compactness, structure, and activity of cellobiohydrolase Cel7A from Trichoderma harzianum

Due to its elevated cellulolytic activity, the filamentous fungus Trichoderma harzianum (T. harzianum) has considerable potential in biomass hydrolysis application. Cellulases from Trichoderma reesei have been widely used in studies of cellulose breakdown. However, cellulases from T. harzianum are less-studied enzymes that have not been characterized biophysically and biochemically as yet. Here, we examined the effects of pH and temperature on the secondary and tertiary structures, compactness, and enzymatic activity of cellobiohydrolase Cel7A from T. harzianum (Th Cel7A) using a number of biophysical and biochemical techniques. Our results show that pH and temperature perturbations affect Th Cel7A stability by two different mechanisms. Variations in pH modify protonation of the enzyme residues, directly affecting its activity, while leading to structural destabilization only at extreme pH limits. Temperature, on the other hand, has direct influence on mobility, fold, and compactness of the enzyme, causing unfolding of Th Cel7A just above the optimum temperature limit. Finally, we demonstrated that incubation with cellobiose, the product of the reaction and a competitive inhibitor, significantly increased the thermal stability of Th Cel7A. Our studies might provide insights into understanding, at a molecular level, the interplay between structure and activity of Th Cel7A at different pH and temperature conditions.     

Selection and characterization of Argentine isolates of <Emphasis Type="Italic">Trichoderma harzianum</Emphasis> for effective biocontrol of Septoria leaf blotch of wheat

Species of the genus Trichoderma are economically important as biocontrol agents, serving as a potential alternative to chemical control. The applicability of Trichoderma isolates to different ecozones will depend on the behavior of the strains selected from each zone. The present study was undertaken to isolate biocontrol populations of Trichoderma spp. from the Argentine wheat regions and to select and characterize the best strains of Trichoderma harzianum by means of molecular techniques. A total of 84 out of the 240 strains of Trichoderma were able to reduce the disease severity of the leaf blotch of wheat. Thirty-seven strains were selected for the reduction equal to or greater than 50 % of the severity, compared with the control. The percentage values of reduction of the pycnidial coverage ranged between 45 and 80 %. The same last strains were confirmed as T. harzianum by polymerase chain reaction amplification of internal transcribed spacers, followed by sequencing. Inter-simple sequence repeat was used to examine the genetic variability among isolates. This resulted in a total of 132 bands. Further numerical analysis revealed 19 haplotypes, grouped in three clusters (I, II, III). Shared strains, with different geographical origins and isolated in different years, were observed within each cluster. The origin of the isolates and the genetic group were partially related. All isolates from Paraná were in cluster I, all isolates from Lobería were in cluster II, and all isolates from Pergamino and Santa Fe were in cluster III. Our results suggest that the 37 native strains of T. harzianum are important in biocontrol programs and could be advantageous for the preparation of biopesticides adapted to the agroecological conditions of wheat culture.     

Mycolytic effect of extracellular enzymes of antagonistic microbes to Colletotrichum falcatum,red rot pathogen of sugarcane

Strains of selected bacteria and Trichoderma harzianum isolated from sugarcane rhizosphere and endosphere regions were tested for the production of chitinolytic enzymes and their involvement in the suppression of Colletotrichum falcatum, red rot pathogen of sugarcane. Among several strains tested for chitinolytic activity, 12 strains showed a clearing zone on chitin-amended agar medium. Among these, bacterial strains AFG2, AFG 4, AFG 10, FP7 and VPT4 and all the tested T. harzianum strains produced clearing zones of a size larger than 10 mm. The antifungal activity of these strains increased when chitin was incorporated into the medium. Trichoderma harzianum strain T5 showed increased levels of activity of N-acetylglucosaminidase and -1,3-glucanase when grown on minimal medium containing chitin or cell wall of the pathogen. Lytic enzymes of bacterial strains AFG2, AFG4, VPT4 and FP7 and T. harzianum T5 inhibited conidial germination and mycelial growth of the pathogen. Enzymes from T. harzianum T5 were found to be the most effective in inhibiting the fungus. When mycelial discs of the pathogen were treated with the enzymes, electrolytes were released from fungal mycelia. The results indicated that antagonistic T. harzianum T5 caused a higher level of lysis of the pathogen mycelium, and the inhibitory effect was more pronounced when the lytic enzymes were produced using chitin or cell wall of the pathogen as carbon source.     

Isolation and characterization of PRA1, a trypsin-like protease from the biocontrol agent <Emphasis Type="Italic">Trichoderma harzianum</Emphasis> CECT 2413 displaying nematicidal activity

Mycoparasitic Trichoderma strains secrete a complex set of hydrolytic enzymes under conditions related to antagonism. Several proteins with proteolytic activity were detected in culture filtrates from T. harzianum CECT 2413 grown in fungal cell walls or chitin and the protein responsible for the main activity (PRA1) was purified to homogeneity. The enzyme was monomeric, its estimated molecular mass was 28 kDa (SDS-PAGE), and its isoelectric point 4.7–4.9. The substrate specificity and inhibition profile of the enzyme correspond to a serine-protease with trypsin activity. Synthetic oligonucleotide primers based on N-terminal and internal sequences of the protein were designed to clone a full cDNA corresponding to PRA1. The protein sequence showed <43% identity to mammal trypsins and 47–57% to other fungal trypsin-like proteins described thus far. Northern analysis indicated that PRA1 is induced by conditions simulating antagonism, is subject to nitrogen and carbon derepression, and is affected by pH in the culture media. The number of hatched eggs of the root-knot nematode Meloidogyne incognita was significantly reduced after incubation with pure PRA1 preparations. This nematicidal effect was improved using fungal culture filtrates, suggesting that PRA1 has additive or synergistic effects with other proteins produced during the antagonistic activity of T. harzianum CECT 2413. A role for PRA1 in the protection of plants against pests and pathogens provided by T. harzianum CECT 2413 is proposed.     

<Emphasis Type="Italic">Trichoderma harzianum</Emphasis>: occurrence in the air and clinical significance

Trichoderma harzianum, a filamentous fungus, is being widely used as a potential biopesticide. The potential of this fungus in causing skin sensitization, however, was poorly investigated as yet. The objective of this study was to monitor the occurrence of T. harzianum in the air and to explore its skin sensitizing potential. Seasonal periodicity of T. harzianum was studied for the years 2002–2004 by an Andersen air sampler. The skin sensitizing potential of T. harzianum extract was studied in 389 patients with suspected respiratory allergy by skin prick test (SPT) and specific IgE level was determined by ELISA. SDS–PAGE and immunoblotting were also performed. T. harzianum colony count varied from 3.69 to 134.88 CFU m⁻³ with the peak achieved in February. Relative humidity was found to be a significant (P < 0.05) factor predicting the occurrence of T. harzianum in the air. Positive skin reaction (wheal diameter ≥ 3 mm) was observed in 105 patients (26.99%). T. harzianum crude extract was resolved in 18 protein bands (12–72 kDa) on SDS–PAGE (12% gel) including two IgE-binding protein bands (21 and 32 kDa). T. harzianum can be considered an important inhalant allergen.     

<Emphasis Type="Italic">Trichoderma harzianum</Emphasis>: a biocontrol agent against <Emphasis Type="Italic">Bipolaris oryzae</Emphasis>

Rice brown spot, caused by Bipolaris oryzae, can be a serious disease causing a considerable yield loss. Trichoderma harzianum is an effective biocontrol agent for a number of plant fungal diseases. Thus, this research was carried out to investigate the mechanisms of action by which T. harzianum antagonizes Bipolaris oryzae in vitro, and the efficacy of spray application of a spore suspension of T. harzianum for control of rice brown spot disease under field conditions. In vitro, the antagonistic behavior of T. harzianum resulted in the overgrowth of B. oryzae by T. harzianum, while the␣antifungal metabolites of T.␣harzianum completely prevented the linear growth of B. oryzae. Light and scanning electron microscope (SEM) observations showed no evidence that mycoparasitism contributed to the aggressive nature of the tested isolate of T. harzianum against B. oryzae. Under field conditions, spraying of a spore suspension of T. harzianum at 10⁸ spore ml⁻¹ significantly reduced the disease severity (DS) and disease incidence (DI) on the plant leaves, and also significantly increased the grain yield, total grain carbohydrate, and protein, and led to a significant increase in the total photosynthetic pigments (chlorophyll a and b and carotenoids) in rice leaves.     

Interspecific differences in radial oxygen loss from the roots of three <Emphasis Type="Italic">Typha</Emphasis> species

A comparison was made of the radial oxygen loss (ROL) from the roots of three Typha species, Typha latifolia L., Typha orientalis Presl and Typha angustifolia L., which resemble each other in morphology. ROLs were evaluated in the laboratory for seedlings of T. orientalis and T. angustifolia in order to compare them with the ROL value for T. latifolia obtained in our previous study. Measurements were conducted using the highly oxygen-sensitive anthraquinone radical anion as an oxygen indicator, which enabled us to simulate the natural conditions in which the oxygen released from the root is immediately consumed by the soil. Among the three Typha species, the ROL was the highest in T. angustifolia, followed by T. latifolia and T. orientalis. Illumination significantly enhances the ROL of T. orientalis, and this effect was also observed for T. latifolia in our previous study, whereas it did not affect the ROL of T. angustifolia. These results indicate that ROL differs significantly between species, even among members of the same genus that are similar in morphology.     

The <Emphasis Type="Italic">Trichoderma harzianum</Emphasis> demon: complex speciation history resulting in coexistence of hypothetical biological species,recent agamospecies and numerous relict lineages

Background  

The mitosporic fungus Trichoderma harzianum (Hypocrea, Ascomycota, Hypocreales, Hypocreaceae) is an ubiquitous species in the environment with some strains commercially exploited for the biological control of plant pathogenic fungi. Although T. harzianum is asexual (or anamorphic), its sexual stage (or teleomorph) has been described as Hypocrea lixii. Since recombination would be an important issue for the efficacy of an agent of the biological control in the field, we investigated the phylogenetic structure of the species.     

Specific PCR Assays for the Detection and Quantification of DNA from the Biocontrol Strain Trichoderma harzianum 2413 in Soil

Strain identification in situ is an important factor in the monitoring of microorganisms used in the field. In this study, we demonstrated the use of sequence-characterized amplified region (SCAR) markers to detect genomic DNA from Trichoderma harzianum 2413 from soil. Two primers (SCAR A1/SCAR A1c) were tested against DNA of 27 isolates of Trichoderma spp. and amplified a 990-bp fragment from T. atroviride 11 and a 1.5-kb fragment from T. harzianum 2413, using an annealing temperature of 68°C. These fragments showed no significant homology to any sequence deposited in the databases. The primer pair, BR1 and BR2, was designed to the 1.5-kb fragment amplified from T. harzianum 2413, generating a SCAR marker. To test the specificity of these primers, experiments were conducted using the DNA from 27 Trichoderma spp. strains and 22 field soil samples obtained from four different countries. PCR results showed that BR1 and BR2 amplified an 837-bp fragment unique to T. harzianum 2413. Assays in which total DNA was extracted from sterile and nonsterile soil samples, inoculated with spore or mycelium combinations of Trichoderma spp. strains, indicated that the BR1 and BR2 primers could specifically detect T. harzianum 2413 in a pool of mixed DNA. No other soil-microorganisms containing these sequences were amplified using these primers. To test whether the 837-bp SCAR marker of T. harzianum 2413 could be used in real-time PCR experiments, new primers (Q2413f and Q2413r) conjugated with a TaqMan fluorogenic probe were designed. Real-time PCR assays were applied using DNA from sterile and nonsterile soil samples inoculated with a known quantity of spores of Trichoderma spp. strains.     

Use of Trichoderma harzianum and Gliocladium vitens for the Biological Control of Post-emergence Damping-off and Root Rot of Cucumbers Caused by Pythium ultimum

The antagonist strains Gliocladium virens G2 and Trichoderma harzianum T3 originally isolated from Pythium suppressive peat, and two benomyl-resistant strains of T. harzianum, T12B and T95, were evaluated as biological control agents of damping-off and root rot of cucumbers in sphagnum peat caused by Pythium ultimum. All strains were equally effective when applied as 1 % peat-bran preparations, whereas the effectiveness of disease control was reduced at higher concentrations of the antagonists. The two wild-type strains were also found to be effective when applied as conidial suspensions, and in this case no reduction in disease control was seen at higher concentrations. G. virens G2 and T. harzianum T12B showed antibiotic activity against P. ultimum in in vitro tests; however there were no signs of mycoparasitism of P. ultimum by any of the antagonist strains.     

Biological Control of Root-Knot Nematode <i>Meloidogyne incognita</i> in <i>Psoralea corylifolia</i> Plant by Enhancing the Biocontrol Efficacy of <i>Trichoderma harzianum</i> Using Press Mud

Meloidogyne incognita is a plant pathogen causing root-knot disease and loss of crop yield. The present study aimed to use Trichoderma harzianum as a biocontrol agent against plant-parasitic nematodes and used press mud, which is a solid waste by-product of sugarcane, as a biocontrol agent and biofertilizer. Therefore, the combined application of T. harzianum and press mud may enhance nematode control and plant growth. Elemental analysis of press mud using scanning electron microscopy (SEM) integrated with an Energy Dispersive X-ray (EDX) analyzer revealed the presence of different elements such as C, O, Mg, Si, P, K, Ca, Cu and Zn. In addition, a greenhouse study was conducted to investigate the combined effects of press mud and T. harzianum on M. incognita reproduction and growth and the biochemical features of Psoralea corylifolia. The results showed that plant length, dry biomass, leaf area, the number of seeds per plant, chlorophyll a, chl b, carotenoid content, nitrate reductase, carbonic anhydrase, and nitrogen content were significantly increased (P ≤ 0.05) in the T2 plants (plants were treated with 100 g of press mud + 50 mL T. harzianum before one week of M. incognita inoculation), over inoculated plants (IC). Antioxidant enzyme activity of ascorbate peroxidase (APX), catalase (CAT), peroxidase (POD), and superoxide dismutase (SOD) in the foliage of P. corylifolia was significantly increased when plants were treated with press mud + T. harzianum. A significant reduction in the number of egg masses, nematode population, and root-knot index (RKI) was found in plants with T2 plants. These results suggest that the combined application of T. harzianum and press mud has the potential to control the M. incognita infection and can be used as an environmentally safe alternative to chemical nematicides and also help in the removal of sugarcane waste that causes environmental pollution.     

Impact of biological control agents on fusaric acid secreted from <Emphasis Type="Italic">Fusarium oxysporum</Emphasis> f. sp. <Emphasis Type="Italic">gladioli</Emphasis> (Massey) Snyder and Hansen in <Emphasis Type="Italic">Gladiolus grandiflorus</Emphasis> corms

Fusaric acid (FA) (5-n-butylpuridine 2-carboxyl acid), a highly toxic secondary metabolite produced by Fusarium oxysporum strains, plays a significant role in disease development. The abilities of three F. oxysporum f. sp. gladioli (Massey) Snyder and Hansen isolates (G010; 649-91; and 160-57) to produce FA in infected Gladiolus corm tissues was evaluated in vitro in relation to the presence of two biological control agents, Trichoderma harzianum T22, and Aneurinobacillus migulanus. Pathogenicity tests were used to differentiate between the abilities of the F. oxysporum strains to secrete FA. FA was identified using LC/MS and quantified using HPLC. Isolate G010 was significantly more virulent (P < 0.01) on Gladiolus grandiflorus corms; it secretes 1.8 μM FA/g fresh weight corm into inoculated Gladiolus. Moreover, G010 was the only isolate that produced FA among the three examined isolates. There was a correlation between the corm lesion area and the FA secretion ability of F. oxysporum f. sp. gladioli (P < 0.001; r ² = 0.96). No FA was detected in PDA cultures of F.oxysporum f. sp. gladioli isolates. The presence of T. harzianum T22 appeared to prevent FA secretion into the corms. In the presence of A. migulanus, however, the amount of FA secreted into the corm tissues increased. These results support the use of T. harzianum as an effective biological control agent against F. oxysporum f. sp. gladioli.     

Biological efficacy of <Emphasis Type="Italic">Trichoderma harzianum</Emphasis> isolate to control some fungal pathogens of wheat (<Emphasis Type="Italic">Triticum aestivum</Emphasis>) in Turkey

Gaeumannomyces graminis var. tritici, Fusarium culmorum and F. moniliforme are highly important and widespread pathogens of wheat in Turkey. Trichoderma isolates have been used as biocontrol agents to protect plants against soilborne diseases in several crops. The present work was carried out to evaluate the potential of Trichoderma harzianum isolate T1 as biocontrol agents for G. graminis, F. culmorum and F. moniliforme under field conditions in 2001 and 2002. Quantitative differences were found in microbial number in soil. T. harzianum T1 had considerable effect on population densities of the tested pathogens. The total number of G. graminis, F. culmorum and F. moniliforme were lower in the T. harzianum T1 application made to seed. T. harzianum T1 application to seed had increasing affect on the yield components of wheat through better control over pathogens. The greatest counts of T. harzianum T1 were detected on root segments. Seed application by T. harzianum T1 had increasing effect on yield components of wheat.