Trichoderma harzianum

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

Microbial consortium-mediated reprogramming of defence network in pea to enhance tolerance against Sclerotinia sclerotiorum.

Abstract: Aims: To evaluate the potentiality of three rhizosphere microorganisms in suppression of Sclerotinia rot in pea in consortia mode and their impact on host defence responses. Methods and Results: Pseudomonas aeruginosa PJHU15, Trichoderma harzianum TNHU27 and Bacillus subtilis BHHU100 from rhizospheric soils were selected based on compatibility, antagonistic and plant growth promotion activities. The microbes were used as consortia to assess their ability to trigger the phenylpropanoid and antioxidant activities and accumulation of proline, total phenol and pathogenesis-related (PR) proteins in pea under the challenge of the soft-rot pathogen Sclerotinia sclerotiorum. The triple-microbe consortium and single-microbe treatments showed 1·4–2·3 and 1·1–1·7-fold increment in defence parameters, respectively, when compared to untreated challenged control. Activation of the phenylpropanoid pathway and accumulation of total phenolics were highest at 48 h, whereas accumulation of proline and PR proteins along with activities of the antioxidant enzymes was highest at 72 h. Conclusions: The compatible microbial consortia triggered defence responses in an enhanced level in pea than the microbes alone and provided better protection against Sclerotinia rot. Significance and Impact of the Study: Rhizosphere microbes in consortium can enhance protection in pea against the soft-rot pathogen through augmented elicitation of host defence responses.

Degradation of organochlorine pesticides, particularly endosulfan, by Trichoderma harzianum

Abstract: A fungus, Trichoderma harzianum, was found to degrade DDT, dieldrin, endosulfan, pentachloronitrobenzene, and pentachlorophenol but not hexachlorocyclohexane. The fungus degraded endosulfan under various nutritional conditions throughout its growth stages. Endosulfan sulfate and endosulfan diol were detected as the major fungal metabolites of endosulfan. Piperonyl butoxide, when added to the growth medium, completely inhibited the endosulfan degradation. Di-n-propyl malaoxon also inhibited the overall endosulfan degradation, but under such an inhibitory condition the formation of endosulfan sulfate was still observed. Using a cell-free preparation from Trichoderma harzianum, we could demonstrate that endosulfan metabolism in vitro was stimulated by exogenously added NADPH. Together with the evidence that the initial metabolic product of endosulfan was endosulfan sulfate, we concluded that the major enzyme system responsible in Trichoderma harzianum responsible for degradation of endosulfan is an oxidative system.

Factors affecting the production of Trichoderma harzianum secondary metabolites during the interaction with different plant pathogens

Abstract: Aims: Strains of Trichoderma spp. produce numerous bioactive secondary metabolites. The in vitro production and antibiotic activities of the major compounds synthesized by Trichoderma harzianum strains T22 and T39 against Leptosphaeria maculans, Phytophthora cinnamomi and Botrytis cinerea were evaluated. Moreover, the eliciting effect of viable or nonviable biomasses of Rhizoctonia solani, Pythium ultimum or B. cinerea on the in vitro production of these metabolites was also investigated. Methods and Results: T22azaphilone, 1-hydroxy-3-methyl-anthraquinone, 1,8-dihydroxy-3-methyl-anthraquinone, T39butenolide, harzianolide, harzianopyridone were purified, characterized and used as standards. In antifungal assays, T22azaphilone and harzianopyridone inhibited the growth of the pathogens tested even at low doses (1–10 μg per plug), while high concentrations of T39butenolide and harzianolide were needed (>100 μg per plug) for inhibition. The in vitro accumulation of these metabolites was quantified by LC/MS. T22azaphilone production was not enhanced by the presence of the tested pathogens, despite its antibiotic activity. On the other hand, the anthraquinones, which showed no pathogen inhibition, were stimulated by the presence of P. ultimum. The production of T39butenolide was significantly enhanced by co-cultivation with R. solani or B. cinerea. Similarly, viable and nonviable biomasses of R. solani or B. cinerea increased the accumulation of harzianopyridone. Finally, harzianolide was not detected in any of the interactions examined. Conclusions: The secondary metabolites analysed in this study showed different levels of antibiotic activity. Their production in vitro varied in relation to: (i) the specific compound; (ii) the phytopathogen used for the elicitation; (iii) the viability of the elicitor; and (iv) the balance between elicited biosynthesis and biotransformation rates. Significance and Impact of the Study: The use of cultures of phytopathogens to enhance yields of Trichoderma metabolites could improve the production and application of novel biopesticides and biofertilizers based on the active compounds instead of the living microbe. This could have a significant beneficial impact on the management of diseases in crop plants.