Trichoderma harzianum

About: Trichoderma harzianum is a research topic. Over the lifetime, 4731 publications have been published within this topic receiving 96796 citations.

The role of recognition in the induction of specific chitinases during mycoparasitism by Trichoderma harzianum

Abstract: Summary: The induction of chitinolytic enzymes in the biocontrol agent Trichoderma harzianum during parasitism on Sclerotium rolfsii and the role of fungal-fungal recognition in this process were studied. A change in the chitinolytic enzyme profile was detected during the interaction between the fungi, grown in dual culture on synthetic medium. Before coming into contact with each other, both fungi contained a protein with constitutive 1,4-†bT-N-acetylglucosaminidase activity. As early as 12 h after contact, the chitinolytic activity in S. rolfsii disappeared, while that of T. harzianum (a protein with a molecular mass of 102 kDa, CHIT 102) greatly increased. After 24 h of interaction, the activity of CHIT 102 diminished concomitantly with the appearance of a 73 kDa 1,4-β-N-acetylglucosaminidase, which became clear and strong at 48 h. This phenomenon did not occur if the S. rolfsii mycelium was autoclaved prior to incubation with T. harzianum, suggesting its dependence on vital elements from the host. Cycloheximide inhibited this phenomenon, indicating that de novo synthesis of enzymes is taking place in Trichoderma during these stages of the parasitism. A biomimetic system based on the binding of a purified surface lectin from the host S. rolfsii to nylon fibres was used to dissect the effect of recognition. An increase in CHIT 102 activity was detected, suggesting that the induction of chitinolytic enzymes in Trichoderma is an early event which is elicited by the recognition signal (i.e. lectin-carbohydrate interactions). It is postulated that recognition is the first step in a cascade of antagonistic events which triggers the parasitic response in Trichoderma.

Mycoparasitism of the extramatrical phase of Glomus intraradices by Trichoderma harzianum

Abstract: In the present study, the interaction between the saprophytic fungus Trichoderma harzianum and the arbuscular mycorrhizal (AM) fungus Glomus intraradices was studied by transmission electron microscopy (TEM) to delineate precisely the relationship established between both partners. An axenic system, divided into four compartments, proved useful for studying the interaction between T. harzianum and the extramatrical phase of G. intraradices. This experimental model, based on root-organ culture to obtain typical mycorrhizal infections, was selected as a reliable means of obtaining mycorrhizal spores and mycelium in root-free compartments. TEM observations of samples from the interaction region showed that hyphae of T. harzianum proliferated abundantly at the spore surface and penetrated the thick host wall through local hydrolysis of the wall polymers. Hyphae of the antagonist also were seen in the subtending hyphae of the AM fungus, and they grew actively in the main host hyphae. This massive colonization was associated with marked cell damage, involving partial to complete disorganization of the cytoplasm, which led in most cases to loss of the protoplasm and apparent bursting of the main hyphae of G. intraradices, resulting in the release of the actively proliferating Trichoderma hyphae. At an advanced stage of the colonization process, the main hyphae of G. intraradices were perforated in many places. The use of wheat germ agglutinin/ovomucoid-gold complex for the localization of chitin monomers resulted in regular labeling of the host cell walls even when spores, subtending hyphae, and main hyphae of G. intraradices were colonized massively. Chitinolytic degradation was seen only in areas adjacent to the sites of Trichoderma penetration. According to our observations, the interaction between T. harzianum and G. intraradices involves the following events : (i) recognition and local penetration of the antagonist into mycorrhizal spores ; (ii) active proliferation of antagonist cells in mycorrhizal hyphae; and (iii) release of the antagonist through moribund hyphal cells.

Evaluation of plant growth promoting activities of microbial strains and their effect on growth and yield of chickpea (Cicer arietinum L.) in India

Abstract: The aims of our study were to enhance growth, yield and disease control of chickpea by various combinations of microbial strains ( Mesorhizobium , Azotobacter chroococcum , Pseudomonas aeruginosa and Trichoderma harzianum ). Pseudomonas and Trichoderma showed positive IAA (indole-3-acetic acid) production, phosphate solubilisation and antagonistic activities against Fusarium oxysporum and Rhizoctonia solani as compared to other strains. In two year investigations, tetra-inoculants have shown significant growth attributes, yield and phytopathogen growth inhibition followed by tri-inoculants than control. Therefore, tetra-inoculants ( Mesorhizobium - Azotobacter-Pseudomonas-Trichoderma ) may be used as efficient biofertilizer and bio-control agent for chickpea production ( Cicer arietinum L.) in eastern Uttar Pradesh.

Biological potantial of some Iranian Trichoderma isolates in the control of soil borne plant pathogenic fungi

Abstract: In this study the in vitro potential of six selected Iranian isolates of three species of Trichoderma (Trichoderma hamatum T614, T. hamatum T612, Trichoderma harzianum T447, T. harzianum T969, Trichoderma virens T523 and Trichoderma sp. T) were evaluated against five isolates of soil borne phytopathogenic fungi (Fusarium graminearum, Rhizoctonia solani (AG4 and AG5), Macrophomina phaseoli and Phytophtora cacturum) in dual culture techniques and through production of volatile and non-volatile inhibitors, and the pH and temperature effects on Trichoderma mycelial growth were also evaluated. All Trichoderma isolates had a marked statistical inhibitory effect on mycelial growth of the pathogens in dual culture compared with controls. Maximum inhibitions occurred in F. graminearum-T. hamatum T614 interaction. Significant pathogen colony growth inhibitions were observed when exposed to the trapped atmosphere from culture of the Trichoderma. F. graminearum was most susceptible to the volatile inhibitors produced by T. hamatum T612 (%inhibition = 48.65). Medium filtrate obtained the Trichoderma isolate culture also were effected on the pathogen species significantly. Maximum growth inhibition was observed in radial growth of F. graminearum by T. hamatum T612 non volatile metabolites (%inhibition = 38.3). Evaluation of pH and temperature effects on Trichoderma isolates mycelial growth showed that Trichoderma strains were found to be able to display activities under a wider range of pH values. Also, Trichoderma strains are mesophilic.

Degradation of pyrene by indigenous fungi from a former gasworks site

Abstract: Indigenous fungi isolated from soil of a former gasworks site were investigated in submerged cultures with pyrene as the sole carbon source. Five fungal strains capable of degrading pyrene included one strain of Trichoderma harzianum and four strains with characteristics of the genus Penicillium. These are identified as Penicillium simplicissimum, Penicillium janthinellum, Penicillium funiculosum and Penicillium terrestre. A maximum of 75% of 50 mg l−1 and 67% of 100 mg l−1 of pyrene was removed by the fast degrading strain P. terrestre at 22°C during 28 days of incubation. The slower degrader P. janthinellum was able to remove 57% of 50 mg l−1 and about 31.5% of 100 mg l−1 pyrene. Degradation of pyrene is directly correlated with biomass development. To the best of our knowledge, this is the first time that fungi have been reported to use pyrene as the sole carbon and energy source. They may be ideal candidates for effective bioremediation of polycyclic aromatic hydrocarbons.