Trichoderma Strains Research Articles

Changes in Peptaibol Production of Trichoderma Species during In Vitro Antagonistic Interactions with Fungal Plant Pathogens.

Trichoderma species are widely used as biofungicides for the control of fungal plant pathogens. Several studies have been performed to identify the main genes and compounds involved in Trichoderma–plant–microbial pathogen cross-talks. However, there is not much information about the exact mechanism of this profitable interaction. Peptaibols secreted mainly by Trichoderma species are linear, 5–20 amino acid residue long, non-ribosomally synthesized peptides rich in α-amino isobutyric acid, which seem to be effective in Trichoderma–plant pathogenic fungus interactions. In the present study, reversed phase (RP) high-performance liquid chromatography (HPLC) coupled with electrospray ionization (ESI) mass spectrometry (MS) was used to detect peptaibol profiles of Trichoderma strains during interactions with fungal plant pathogens. MS investigations of the crude extracts deriving from in vitro confrontations of Trichoderma asperellum and T. longibrachiatum with different plant pathogenic fungi (Fusarium moniliforme, F. culmorum, F. graminearum, F. oxysporum species complex, Alternaria solani and Rhizoctonia solani) were performed to get a better insight into the role of these non-ribosomal antimicrobial peptides. The results revealed an increase in the total amount of peptaibols produced during the interactions, as well as some differences in the peptaibol profiles between the confrontational and control tests. Detection of the expression level of the peptaibol synthetase tex1 by qRT-PCR showed a significant increase in T. asperellum/R. solani interaction in comparison to the control. In conclusion, the interaction with plant pathogens highly influenced the peptaibol production of the examined Trichoderma strains.

Evaluation of cellulolytic exogenous enzyme-containing microbial inoculants as feed additives for ruminant rations composed of low-quality roughage

AbstractThe supplementation of ruminant diets with exogenous cellulolytic enzymes can improve their digestibility and feeding value. The objective of this study was to determine the effect of supplementing roughage (rice straw) and concentrate with inoculants containing four fungal strains (Pleurotus ostreatus, Phanerochaete chrysosporium, Trichoderma reesei and Trichoderma viride) and four bacterial strains (Paenibacillus polymyxa, Bacillus megaterium, Bacillus circulans and Bacillus subtilis), given separately or as a mixture, as a source of exogenous cellulolytic enzymes, on basic rumen parameters in vitro, including digestibility and methane production. A batch culture trial was used to select the best supplements, and a long-term rumen simulation technique (RUSITEC) was used to evaluate the effects of P. chrysosporium, B. subtilis, and a 1 : 1 mixture of these two on dietary component digestibility and fermentation parameters. In the batch culture evaluation, there were significant increases in the organic matter (OM) digestibility, the total gas production expressed as ml/g of dry matter, the OM, the neutral detergent fibre (NDF) and the acid detergent fibre (ADF) of the supplemented rations, as compared to the control, excluding the rations supplemented with T. viride and B. circulans. In the RUSITEC, the ration supplemented with mixed inoculants showed significantly higher digestibility of crude protein, ether extract, NDF and ADF than did the ration supplemented with the P. chrysosporium and B. subtilis inoculants. It can be concluded that the simultaneous use of fungal and bacterial exogenous cellulases on rice straw roughage improves its digestibility, without negative effects on other rumen parameters.

Effectiveness of Trichoderma strains isolated from the rhizosphere of citrus tree to control Alternaria alternata, Colletotrichum gloeosporioides and Penicillium digitatum A21 resistant to pyrimethanil in post-harvest oranges (Citrus sinensis L. (Osbeck)).

Penicillium digitatum, Alternaria alternata and Colletotrichum gloeosporioides are pathogens responsible for large decays and production losses of citrus. They are commonly controlled by fungicides, whose excessive applications have led to the emergence of resistant P. digitatum strains. Alternative approaches are imperative for sustainable and environmental harmless citrus production, being biological control a promising strategy. The objective was to evaluate the potential of Trichoderma strains native from the rhizosphere of citrus trees to control these pathogens. Seven strains were isolated and identified as Trichoderma harzianum, T. guizhouense, T. atroviride and T. koningiopsis through morphological and molecular analyses. Five of them showed effective antagonist performance in vitro against the pathogens. The strain T. harzianum IC-30 was the best biological control agent in vivo, obtaining a reduction of rot percentage around 80% after 3weeks of infection of oranges with P. digitatum A21 (resistant to pyrimethanil). This strain also showed the highest chitinase and glucanase activities. Trichoderma harzianum IC-30 is an optimal antagonist for the control of green mould spreading and other pathogens in post-harvest citrus fruits. The strain combined with supplementary practices could lead to sustainable management of citrus fungal diseases, dispensing with synthetic fungicides.

Modification of post-industrial lignin by fungal strains of the genus Trichoderma isolated from different composting stages

One of the links in the environmental management chain is the environmentally friendly utilization of the emerging post-industrial waste and improvement of the methods of processing thereof. The aim and novelty of this research was to evaluate the potential of fungi to purify wastewater containing post-industrial lignin, i.e. waste originating from the pulp and paper industry. Trichoderma were dominant in the composts with different qualities and quantities of lignocellulosic compounds. The Trichoderma strains used in the research were isolated from two lignocellulosic composts at three different time points (from 10-, 20- and 30-week-old composting mass). Eighteen strains of the genus Trichoderma were tested for their ability to biodegrade 0.2% post-industrial lignin. It was evaluated by determination of decolorization, activities of ligninolytic enzymes, and concentration of phenolic compounds in the post-culture liquid. The Trichoderma strains isolated from 10-week-old compost I and 30-week-old compost II showed the highest decolorization activity and biotransformation of dark post-industrial lignin. All strains secreted horseradish-like peroxidase (HRP-like), superoxide dismutase-like (SOD-like), xylanase, and phenolic compounds. Strains isolated from 30-week-old compost I and from 10-week-old compost II released the greatest amounts of phenolic compounds into the culture liquid containing post-industrial lignin. The strains isolated from 10- and 20-week-old compost were characterized by high SOD-like and HRP-like activity, respectively. The concentration of phenolic compounds measured with HPLC in Trichoderma fungus culture VII from compost I corresponded with the decolorization degree and high HRP-like activity. The study results indicate that the genus Trichoderma with decolorization activity isolated from the first composting stages can be used in the biotransformation of post-industrial lignin waste.

Copper tolerant Trichoderma asperellum increases bio-efficacy of copper against Phytophthora infestans in dual combination

Present research was conducted to understand the characteristics of Trichoderma in the development of combination product involving a lower dose of Cu fungicide that showed promise in the effective management of Phytophthora infestans, the late blight pathogen of potato. Based on Cu tolerance activity, potential Trichoderma strains (viz., TCMS-36, SBIT-32 and TCMS-71) were selected. Electron microscopy (SEM and TEM) studies revealed that tolerant Trichoderma isolates (SBIT-32 and TCMS 36) accumulated Cu on the cell wall, while the sensitive isolate (TCMS 71) was repressed due to penetration of Cu through the cell wall. To elucidate Cu-tolerance, Cu-biosorption by living and dead mycelia of T. asperellum was estimated by atomic absorption spectrophotometer. Both sensitive and tolerant T. asperellum isolates accumulated Cu in their cells all through the observation period of 120 h, with considerable increase in the amount of Cu removed from the cell free supernatant from 24 to 120 h. Isolate TCMS-36 recorded maximum Cu accumulation (0.3506 mg/g) in living mycelia, while SBIT-32 recorded highest accumulation (0.2368 mg/g) in dead mycelia. Effectiveness of Cu tolerant T. asperellum was studied in combination with Cu fungicides; viz., COC (Blitox-50), COH (Kocide) in controlling late blight disease in the field. Among three modes of applications, viz., seed, foliar and seed+foliar, maximum delay in progress of the disease was recorded in seed+foliar application. Dual combination of COC@500 ppm and Trichoderma was found more effective than COC alone @1000 ppm in reducing disease severity. Cu tolerant Trichoderma strains could thus be developed as combination products with Cu-based fungicides for safe and effective management of late blight disease of potato.

Bio-stimulant, what is its promoting effect on the cultivation of safflower (Carthamus tinctorius L.)?

The present experimentation evaluated the potential of a bio-stimulant, made by indigenous strains of Trichoderma, on the performance of safflower plants cultivated in the region of Touggourt (Southeastern Algeria). The study was conducted according to seven (07) biometric measurements associated to growth and yield comparing treated and non-treated plants. Results revealed that the biological product has a stimulating efficiency towards all examined parameters. The percentage of germination in the treated plots (93.75%) was more than the non-treated (78.13%). After, it enhanced the growth of safflower plants either in the lifting, flowering, or the time of harvesting clumps and seeds. Furthermore, the treated plants were influenced by the applied bio-stimulant with significant differences in the diameter (2.6 cm; p = 0.01) and the number of principal branches (21.3 branch/plant; p = 0.07) comparing to the control plants. Besides, great efficiency of this bio-product was recorded with very highly significant differences on the weights of fresh (28.63 g; p = 0.000) and dry (1.31 g; p = 0.000) clumps per plant. Also, the statistical analyses applied on the productivity of safflower presented a significant difference (t 2.43, p = 0.018) between the treated plants (20.51 g/day) and the control (7.92 g/day). The present bio-stimulant was very efficient in promoting the growth of safflower crop so that it can be contributed in sustainable organic agriculture.

Morphological and protein alterations in Sclerotinia sclerotiorum (Lib.) de Bary after exposure to volatile organic compounds of Trichoderma spp.

Trichoderma fungi have an important potential for the control of plant diseases due to their various mechanisms of action, such as the production of volatile organic compounds (VOCs). The phytopathogenic fungus Sclerotinia sclerotiorum (Lib.) de Bary causes a disease called white mold, sclerotinia rot or sclerotinia wilt, in several plant species. The objective of this work was to evaluate the mycelial morphology and protein profile of S. sclerotiorum after exposure to VOCs produced by six Trichoderma strains. The assays were performed in the laboratory using inverted plate tests with evaluation of mycelial growth inhibition, microscopic observation of hyphae and MALDI-TOF analysis of S. sclerotiorum protein profile. The best results were obtained from T. azevedoi CEN1241, with up to 35% inhibition of mycelial growth and the greatest inhibitory effect on the production of differential proteins present in S. sclerotiorum control treatment. All tested Trichoderma strains decreased the width of the pathogen’s hyphae. The diversity of Trichoderma species and VOCs produced by strains of this fungus may enable the development of strategies for the use of such compounds in plant disease control. Considering this biological activity, strain CEN1241 shows potential as a biocontrol agent of white mold.

Trichoderma en la Argentina: Estado del arte

Las metodologias que se aplican para manejar los sistemas agricolas y agroforestales tienen efectos notables en la produccion de alimentos y en la conservacion de la biodiversidad. Las enfermedades que causan los hongos fitopatogenos son uno de los problemas criticos en la agricultura argentina. A partir de la necesidad de encontrar mecanismos que eleven la productividad del campo, en los ultimos anos se intensifico la busqueda de estrategias de control de enfermedades agricolas que sean alternativas al control quimico, buscando, ademas, disminuir los riesgos ambientales y sanitarios derivados de este. El hongo Trichoderma es uno de los agentes que mas se usan en los programas de control biologico como reguladores de hongos fitopatogenos. Esta revision tiene como objetivo realizar una compilacion de toda la informacion disponible respecto al estado del arte de Trichoderma como controlador biologico en la Argentina, con el fin de referenciar diferentes instituciones del pais que centralizan a este hongo en sus investigaciones. Cerca de 70 grupos de universidades e institutos de investigacion describieron aproximadamente diez especies diferentes de Trichoderma con capacidad antagonista, se estudiaron alrededor de 35 cultivos y 40 patogenos. La especie de Trichoderma mas utilizada como agente de control biologico es Trichoderma harzianum, seguida por Trichoderma koningii y Trichoderma viride. Actualmente, en el mercado argentino existen cerca de 14 bioproductos cuyo principio activo son cepas de Trichoderma. Las crecientes iniciativas de las instituciones nacionales sobre estos estudios son basicas para el desarrollo de tecnologias innovadoras y para lograr una agricultura mas productiva y ambientalmente sostenible en el pais.https://doi.org/10.25260/EA.20.30.1.0.945

Isolate Neoscytalidium dimidiatum fungal pathogens from pytaya (Hylocereus undatus) and research controlling by microorganisms

In recent years, Neoscytalidium dimidiatum has caused severe white spot disease in Pytaya, while no effective controls have been taken. In this study, two strains of N. dimidiatum NdGV and NdBT were obtained by isolation on water agar medium containing streptomycin, morphological tests, in vitro and in vivo pathogenical tests, and molecular biology tests by sequencing the genes ITS1 and ITS4. By using dual culture technique on potato-glucose agar medium, 100% of Trichoderma spp., 75% of Bacillus spp. and 20% of Streptomyces spp. were able to antagonize N. dimidiatum. The mean antagonistic effect with N. dimidiatum of Trichoderma spp. was higher than Bacillus spp. and the lowest was Streptomyces spp. 56.8%, 55.3% and 54.3% respectively. Especially 5 strains Trichoderma sp. 8.3.5, 8.3.7, 8.3.14, 8.3.19, and 8.3.20 had antagonistic effects of over 60%. The application potential of the 5 selected Trichoderma strains to control N. dimidiatum disease was further strengthened when their antagonistic effect was relatively stable on Pitaya juice agar medium while all Bacillus sp. and Streptomyces sp. were lost the ability to antagonize. It was noteworthy that four of the five strains of Trichoderma sp. were highly compatible, suggesting further studies are needed to apply their combined potency in enhancing the control of N. dimidiatum NdBT and NdGV on Pitaya.

On-farm validation of management technology for seed and soil borne safflower diseases

On farm validation for seed and soil borne safflower disease management technology was conducted at Parbhani to evaluate the Trichoderma strain (Th4d)) as seed dresser compared with farmers’ practice. The seed treatments, Trichoderma harzianum Th4d SC @ 2 ml/kg and Trichoderma harzianum Th4d WP @ 10 g/kg were most effective with significantly least incidence of 5.3% of seed/soil borne disease as compared to farmers’ practice where the disease incidence was 11.3%. The treatment Trichoderma harzianum Th4d SC @ 2 ml/kg and Trichoderma harzianum Th4d WP @ 10 g/kg also recorded highest seed yield (1034 and 1055 kg/ha) followed by Carbendazim+Mancozeb (SAFF) @ 0.2% (977 kg/ha). The cost-benefit analysis showed that the seed treatment with Trichoderma harzianum Th4d WP @ 10 g/kg recorded the highest net monetary returns of `16,700/-.

Trichoderma from Brazilian garlic and onion crop soils and description of two new species: Trichoderma azevedoi and Trichoderma peberdyi.

Fifty four Trichoderma strains were isolated from soil samples collected from garlic and onion crops in eight different sites in Brazil and were identified using phylogenetic analysis based on combined ITS region, tef1-α, cal, act and rpb2 sequences. The genetic variability of the recovered Trichoderma species was analysed by AFLP and their phenotypic variability determined using MALDI-TOF. The strain clusters from both typing techniques coincided with the taxonomic determinations made from phylogenetic analysis. The phylogenetic analysis showed the occurrence of Trichoderma asperellum, Trichoderma asperelloides, Trichoderma afroharzianum, Trichoderma hamatum, Trichoderma lentiforme, Trichoderma koningiopsis, Trichoderma longibrachiatum and Trichoderma erinaceum, in the soil samples. We also identified and describe two new Trichoderma species, both in the harzianum clade of section Pachybasium, which we have named Trichoderma azevedoi sp. nov. and Trichoderma peberdyi sp. nov. The examined strains of both T. azevedoi (three strains) and T. peberdyi (12 strains) display significant genotypic and phenotypic variability, but form monophyletic clades with strong bootstrap and posterior probability support and are morphologically distinct from their respective most closely related species.

Isolation of Trichoderma in the rhizosphere soil of Syringa oblata from Harbin and their biocontrol and growth promotion function

For the effective biocontrol of Syringa powdery mildew (Mircosphaera syringejaponicae) and to promote seedling growth, we identified 44 of the 181 Trichoderma isolates (T1-T181) isolated from the rhizosphere soil. Analysis identified 10 Trichoderma species, and T. pseudoharzianum T1 (TpseT1), T. afroharzianum T52 (TafrT52), and T. asperelloides T57 (TaspT57) were selected to make Trichoderma biofertilizer because of their fast growth and high spore production. Exposing Syringa oblata to Trichoderma biofertilizer showed that TafrT52 and TaspT57 could induce abscisic acid (ABA) production, and promote the shedding of diseased leaves and the generation of new leaves. Furthermore, TafrT52 increased the catalase (CAT) activity and reduced the H2O2 content. And the disease incidence was reduced by 37.84 % by Tasp (highest) in 2017 year and by 13.84 % by TpseT1(lowest) in 2018 year. In addition, all Trichoderma strains we selected could promote the lateral root growth of S. oblata seedlings; however, because of the downregulated gene expression at the late stage of chlorophyll synthesis, the chlorophyll content decreased in the new leaves. Antagonism among different Trichoderma species led to low biocontrol and growth promotion effects, thus the Trichoderma mixture cannot be use as biofertilizer. TafrT52, with better biocontrol and growth promotion effects, could be used for biocontrol of M. syringejaponicae.

AUXIN RESPONSE FACTOR 1 Acts as a Positive Regulator in the Response of Poplar to Trichoderma asperellum Inoculation in Overexpressing Plants.

Numerous Trichoderma strains have been reported to be optimal biofertilizers and biocontrol agents with low production costs and environmentally friendly properties. Trichoderma spp. promote the growth and immunity of plants by multiple means. Interfering with the hormonal homeostasis in plants is the most critical strategy. However, the mechanisms underlying plants’ responses to Trichoderma remain to be further elucidated. Auxin is the most important phytohormone that regulates almost every aspect of a plant’s life, especially the trade-off between growth and defense. The AUXIN RESPONSE FACTOR (ARF) family proteins are key players in auxin signaling. We studied the responses and functions of the PdPapARF1 gene in a hybrid poplar during its interaction with beneficial T. asperellum strains using transformed poplar plants with PdPapARF1 overexpression (on transcription level in this study). We report that PdPapARF1 is a positive regulator for promoting poplar growth and defense responses, as does T. asperellum inoculation. PdPapARF1 also turned out to be a positive stimulator of adventitious root formation. Particularly, the overexpression of PdPapARF1 induced a 32.3% increase in the height of 40-day-old poplar plants and a 258% increase in the amount of adventitious root of 3-week-old subcultured plant clones. Overexpressed PdPapARF1 exerted its beneficial functions through modulating the hormone levels of indole acetic acid (IAA), jasmonic acid (JA), and salicylic acid (SA) in plants and activating their signaling pathways, creating similar results as inoculated with T. asperellum. Particularly, in the overexpressing poplar plants, the IAA level increased by approximately twice of the wild-type plants; and the signaling pathways of IAA, JA, and SA were drastically activated than the wild-type plants under pathogen attacks. Our report presents the potential of ARFs as the crucial and positive responders in plants to Trichoderma inducing.

Phosphorus-solubilizing Trichoderma spp. from Amazon soils improve soybean plant growth

Acidic soils rapidly retain applied phosphorus fertilizers and consequently present low availability of this nutrient to plants. The use of phosphate-solubilizing microorganisms to help plant phosphorus (P) absorption is a promising sustainable strategy for managing P deficiencies in agricultural soils. Trichoderma strains have been one of the most studied filamentous fungi for improving the production and development of several crop species mainly due to their capability for symbiotic associations and their ability to control soil-borne plant diseases. Thus, this work sought to bioprospect Trichoderma strains from the Amazon rainforest capable of solubilizing/mineralizing soil phosphate and promoting soybean growth. Soybean plants inoculated with selected Trichoderma strains were cultivated in soil under greenhouse conditions and under a gradient of rock phosphate and triple superphosphate. As a result, 19.5% of the isolated Trichoderma strains were able to solubilize phosphate. In addition, those strains produced different organic acids during the solubilization process. Trichoderma spp. strains showed positive responses in the promotion of soybean growth—from 2.1% to 41.1%—as well as in the efficiency of P uptake-up to 141%. These results reveal the potential of Trichoderma spp. from the Amazon biome as promising biofertilizer agents.

Carbon metabolic profiling of Trichoderma strains provides insight into potential ecological niches

ABSTRACTMany Trichoderma species are cosmopolitan and widespread free-living fungi in various ecological environment, and many are economically important in the fields of agriculture and industry. However, carbon metabolism profiles of Trichoderma species have not been characterized in detail. In this study, Biolog FF MicroPlates were used to contrast carbon utilization and the differences among five Trichoderma species, each representing a unique phenotype. Their metabolic abilities varied greatly. Species producing cellulases and chitinases and with phosphate-solubilizing activities exhibited high efficiency of substrate utilization, whereas low efficiency was shown by saline-alkaline-tolerant species that metabolized simple carbon sources. Species producing cellulases at high levels may be specified to decompose and assimilate cellulose and hemicellulose in woody substrates, and those producing chitinases may have mycoparasitic roles. Species with plant growth–promoting traits are good at uptake of exudates from plant roots. Overall, metabolic models reflect nutritional adaptation of Trichoderma to diverse niches in nature.

Increased activity of the sterol branch of the mevalonate pathway elevates glycosylation of secretory proteins and improves antifungal properties of Trichoderma atroviride

Some Trichoderma spp. have an ability to inhibit proliferation of fungal plant pathogens in the soil. Numerous compounds with a proven antifungal activity are synthesized via the terpene pathway.Here, we stimulated the activity of the mevalonate pathway in T. atroviride P1 by expressing the Saccharomyces cerevisiae ERG20 gene coding for farnesyl pyrophosphate (FPP) synthase, a key enzyme of this pathway. ERG20-expressing Trichoderma strains showed higher activities of FPP synthase and squalene synthase, the principal recipient of FPP in the mevalonate pathway.We also observed activation of dolichyl phosphate mannose (DPM) synthase, an enzyme in protein glycosylation, and significantly increased O- and N-glycosylation of secreted proteins. The hyper-glycosylation of secretory hydrolases could explain their increased activity observed in the ERG20 transformants.Analysis of the antifungal properties of the new strains revealed that the hydrolases secreted by the transformants inhibited growth of a plant pathogen, Pythium ultimum more efficiently compared to the control strain. Consequently, the biocontrol activity of the transgenic strains, determined as their ability to protect bean seeds and seedlings against harmful action of P. ultimum, was also improved substantially.

Bio-organic fertilizer with reduced rates of chemical fertilization improves soil fertility and enhances tomato yield and quality

The extensive use of chemical fertilizers poses serious collateral problems such as environmental pollution, pest resistance development and food safety decline. Researches focused on applying plant-beneficial microorganisms to partially replace chemical fertilizer use is increasing due to the requirement of sustainable agriculture development. Thus to investigate the possibility of a plant-beneficial Trichoderma strain and its bio-organic fertilizer product in saving chemical fertilizer application and in improving crop quality, a field trial and continuous pot experiments were carried out with tomato. Four treatments were set up: a reduced application of chemical fertilizer (75% of the conventional application) plus Trichoderma-enriched bio-organic fertilizer (BF), organic fertilizer (OF) or Trichoderma spore suspension (SS), with using the 100% rate of the conventional chemical fertilizer as the control (CF). The results showed that the total soluble sugar, Vitamin C and nitrate accumulations were, respectively, +up to 24%, +up to 57% and –up to 62% in the tomatoes of the BF treatment compared to those of the control (CF). And both of the pot and field trials revealed that reduced rates of chemical fertilizer plus bio-organic fertilizer produced tomato yields equivalent to those obtained using the 100% of the chemical fertilizer. However, application with the inoculant alone (SS) or combined with the organic fertilizer alone (OF) would lead to a yield decreases of 6–38% and 9–35% over the control. Since the increased abundance of soil microflora and the enhanced soil fertility frequently showed positive linear correlations especially in the BF-treated soils, we conclude that the efficacy of this bio-organic fertilizer for maintaining a stable tomato yield and improving tomato quality may be due to the improved soil microbial activity. Thus, the results suggest that the Trichoderma bio-organic fertilizer could be employed in combination with the appropriate rates of chemical fertilizers to get maximum benefits regarding yield, quality and fertilizer savings.

Mycelial inhibition of Trichoderma spp. isolated from the cultivation of Pleurotus ostreatus with an extract of Pycnoporus sp.

Abstract:Background and Aims: The production of edible fungi is affected by bacterial, fungal and viral diseases, which very often cause large losses. In the productionof mushrooms of the genus Pleurotus, the fungi of Trichoderma spp. represent a serious problem of contamination and although there are some chemical compoundsthat control the infection, they are not entirely safe for human consumption. As a consequence, alternatives are being searched for through biotechnology,such as the one presented in this paper.Methods: Strains of fungi of the genus Trichoderma were isolated from the substrate where Pleurotus ostreatus was being cultivated. These were identifiedmorphologically and molecularly, followed by tests to inhibit the growth of Trichoderma strains in both agar and wheat straw, using a cetonic extract of thedehydrated fruiting body of Pycnoporus sp.Key results: Two strains of Trichoderma (T. pleuroti and T. atrobrunneum, belonging to the clade of T. harzianum) were isolated from infected substrate obtainedin production modules of Pleurotus ostreatus located in Tlaquitenango and Cuernavaca, in the state of Morelos, Mexico. The effect of a cetonic extract of thefruiting body of Pycnoporus sp. on the mycelial growth of the isolated strains of Trichoderma was also evaluated, observing decrease in mycelial growth rate inPetri dish up to 72% and on lignocellulosic substrate both mycelial growth and sporulation were delayed up to 10 days.Conclusions: The extract of Pycnoporus sp. could be an alternative to control the infection by Trichoderma spp. in mushroom cultures of the genus Pleurotus.Key words: disease control, edible mushrooms, lignocellulosic substrate.

Performance of Potent Isolate of Trichoderma harzianum (Th9) Possessing Mycoparasitic Property Against Late Blight Causing Fungus Phytophthora infestans in Addition to Enhancing Defensive Enzymes Activities in Potato Crop

Late blight of potato caused by fungal pathogen Phytophthora infestans is an important disease in potato growing areas around the globe resulting in food shortage, hunger and atleast 50% of crop losses. In the present investigation, two strains of Trichoderma, indigenously isolated Trichoderma harzianum (Th9) and commercial strain of same species tested were used against destructive fungus, Phytopthera infestans through in-vitro studies. Both strains of fungal bioagents showed variation in their potentiality against the rot causing fungus Phytopthera infestans. Trichoderma harzianum (Th9) exhibited highly potential properties as compared to the commercial strain. Biochemical studies revealed that enzymes chitinase and β 1,3 glucanase known for systemic resistance were found in higher concentration in healthy plants of potato as compared to the diseased one. The Th9 strain was, therefore, selected for further Integrated pest management studies either for pure applications and/or as core component of IPM packages on potato crops under field conditions.

ФОРМИРОВАНИЕ СОВМЕСТНЫХ БИОПЛЕНОК ГРИБАМИ РОДА TRICHODERMA И PGP-БАКТЕРИЯМИ В ЛАБОРАТОРНЫХ УСЛОВИЯХ

The capability to formation of combined biofilms by the fungi from Trichoderma genus and several PGP-bacteria including Pseudomonas extremaustralis, P. koreensis, P. mandelii and Advenella kashmirensis has been demonstrated. The strains of Trichoderma used in the experiment not only exert antagonism to phytopathogenic fungi, but also accelerate the decomposition of plant residues. It was found that microscopic fungi whose mycelial structure offers advantages in reaching and assimilating of nutrient substrates, during their growth can favor to directional moving of bacteria cells. The explored bacterial strains moved along the fungal mycelium on the surface of the medium, and in areas where the medium was absent, the bacteria moved inside the hyphae, leaving them when the mycelium reached the substrate. The findings evidence the potential of considered microorganisms for developing of a new generation multifunctional biopreparation for agriculture, contributing not only to crop yield increase and plant protection against phytopathogenic fungi, but also maintaining soil fertility.