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Trichoderma harzianum

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


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Journal ArticleDOI
TL;DR: Results show that application of essential oils in integration with the bio-agent T. harzianum may be considered as an applicable, safe and cost-effective method for controlling such soilborne diseases.
Abstract: Carnation, caraway, thyme, peppermint and geranium essential oils have been found to have inhibitory effects against the mycelial growth of Fusarium solani, Rhizoctonia solani, Sclerotium rolfsii and Macrophomina phaseolina under in vitro conditions. Complete inhibition of fungal growth was observed with the use of 4% carnation and geranium oils. Mycelial growth of the tested fungi showed more sensitivity to high concentrations of thyme than to caraway and peppermint oils. Moreover, essential oils used to coat seeds resulted in a significant reduction of root rot incidence of bean, at both pre- and post-emergence stages under greenhouse conditions. Under field conditions seeds coated with essential oils at a concentration of 4% sown in soil treated with the bio-agent Trihoderma harzia- num, gave pronounced protection to emerged bean seeds against the invasion of root rot pathogenic fungi. Compared to the control, the above treatment resulted in a reduction of disease incidence at the pre-emergence stage. This reduction was calculated to be between 47.3 and 55.4% compared with a 16.1% reduction with the use of the Rizolex-T treatment. At the post-emergence stage, all applied treat- ments were able to reduce the percentage of root-rot incidence. Reduction ranged between 41.4 and 47.1% over the untreated control. Reduction in disease incidence was reflected in a yield increase of 15.1-28.8% and 40.1-50%, in seeds coated with one of the different essential oils, or combined with T. harzianum soil treatments, in the respective order. Seeds coated with the fungicide Rhizolex-T caused a yield increase estimated as 11.3% over the check treatment. These results show that application of essential oils in integration with the bio-agent T. harzianum may be considered as an applicable, safe and cost-effective method for controlling such soilborne diseases.

62 citations

Journal ArticleDOI
TL;DR: Results suggest that TD acts as a signalling VOC in the interactions of Trichoderma with plants and other microorganisms by modulating the perception of this fungus to a given environment, and the TD ability to induce systemic defences indicates that complex trichothecene structures may not be necessary for inducing such responses.
Abstract: Summary Trichothecenes are phytotoxic sesquiterpenic mycotoxins that can act as virulence factors in plant diseases. Harzianum A (HA) is a non-phytotoxic trichothecene produced by Trichoderma arundinaceum. The first step in HA biosynthesis is the conversion of farnesyl diphosphate to trichodiene (TD), a volatile organic compound (VOC), catalysed by a sesquiterpene synthase encoded by the tri5 gene. Expression of tri5 in the biocontrol strain Trichoderma harzianum CECT 2413 resulted in pro- duction of TD in parallel with a reduction of ergosterol biosynthesis and an unexpected increase in the level of squalene. Transformants expressing tri5 displayed low chitinase activity and induced expression of Botrytis cinerea BOT genes, although their total antagonistic potential against phytopathogenic fungi was not reduced. VOCs released by the tri5- transformant induced expression of tomato defence genes related to salicylic acid (SA), and TD itself strongly induced the expression of SA-responsive genes and reduced the development of lateral roots. Together, these results suggest that TD acts as a signalling VOC in the interactions of Trichoderma with plants and other microorganisms by modulating the perception of this fungus to a given environment.

62 citations

Journal ArticleDOI
TL;DR: Among the fusants, the strain SFTh8 produced maximum chitinase with a two-fold increase as compared to the parent strain, and all the self-fusants exhibited increased antagonistic activity against Rhizoctonia solani than the parent.

62 citations

Journal ArticleDOI
TL;DR: The possibility of using mutants with improved constitutive extracellular protease secretion against plant pathogenic fungi is suggested by means of specific chromogenic protease substrates.
Abstract: Several Trichoderma strains have been reported to be effective in controlling plant diseases, and the action of fungal hydrolytic enzymes is considered as the main mechanism involved in the antagonistic process. Strain Trichoderma harzianum T334 is a potential biocontrol agent against plant pathogenic fungi with the ability to produce low levels of proteases constitutively. To improve its fungal antagonistic capacity, mutagenetic program was undertaken for the construction of protease overproducing derivates. The mutant strains were obtained by means of UV-irradiation and were selected for p-fluorophenyl-alanine resistance or altered colony morphology. It was revealed by means of specific chromogenic protease substrates that both trypsin-like and chymotrypsin-like protease secretion was elevated in most of the mutant strains. The profiles of isoenzymes were different between the mutants and the wild-type strain, when examined by gel filtration chromatography. Certain mutants proved to be better antagonists against plant pathogens in in vitro antagonism experiments. This study suggests the possibility of using mutants with improved constitutive extracellular protease secretion against plant pathogenic fungi.

62 citations

Journal ArticleDOI
TL;DR: It is concluded that the transformant was genetically stable when grown in a natural potting mixture and demonstrated the suitability of using a GUS transformant for detecting and monitoring a specific strain of T. harzianum deliberately released into the environment.
Abstract: Population development, activity, and stability of a β-glucuronidase (GUS)-transformed strain of Trichoderma harzianum were studied in the rhizosphere of cucumber plants grown in sphagnum peat. When compared to the wild-type isolate, there was no significant difference in terms of population development (CFU/g of sphagnum peat). In a treatment with a combination of the wild-type isolate and the transformant, the proportion of GUS-active colonies on plates was constant throughout the experiment. On that basis, we concluded that the transformant was genetically stable when grown in a natural potting mixture. GUS was extracted from infested rhizosphere peat and assaved spectrophotometrically. The activity curve was inversely related to the population curve. Quantification of activated conidia by fluorescein diacetate staining indicated that GUS activity correlated with the activity of the fungus. Hyphae of T. harzianum stained with 5-bromo-4-chloro-3-indoyl-β-D-glucuronide were easily detected on the roots, especially around small wounds, such as damaged epidermal cells. Colonization of wounds may be important for the antagonistic effect of the organism, because it may block a possible way for pathogens to infect root tissue. Our results demonstrate the suitability of using a GUS transformant for detecting and monitoring a specific strain of T. harzianum deliberately released into the environment.

62 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023163
2022383
2021200
2020254
2019251
2018228