Trichoderma harzianum

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

Extracellular chitinase production by Trichoderma harzianum in submerged fermentation.

Abstract: Extra-cellular chitinase production by a chitinolytic fungus Trichoderma harzianum TUBF 966 using submerged fermentation was studied. Colloidal chitin (1.5% w/v) was used as sole carbon source. Maximum chitinase production (14.7 U/ml) was obtained when fermentation was carried out at 30 degrees C for 96 h using 72 h old mycelium in a medium containing colloidal chitin 1.5% (w/v) as carbon source and 0.42 (% w/v) peptone as nitrogen source (pH 5.5). Supplementation of additional carbon sources (0.75% w/v) showed no further enhancement in chitinase production while supplementation of nitrogen sources (0.42% w/v) such as peptone and tryptone in the fermentation medium showed a marked increase in production. The process parameters that controlled chitinase production by the fungus were studied and presented here.

Putative Trichoderma harzianum mutant promotes cucumber growth by enhanced production of indole acetic acid and plant colonization

Abstract: Many Trichoderma species are well-known by their ability to promote plant growth and health. However, few studies have been conducted to improve their ability. Laboratory and greenhouse experiments compared the promotion of cucumber growth by the putative mutant Trichoderma harzianum T-E5 versus the wild-type SQR-T037 and bio-organic fertilizers fortified with them. The putative mutant T-E5 was selected based on plant hormone production in liquid fermentation and then on the effects of T-E5 and SQR-T037 to promote plant growth and colonization of plant roots and rhizosphere soil of cucumber. High-performance liquid chromatography analysis showed that indole acetic acid (IAA) production by T-E5 was enhanced by 30.2 % as compared with SQR-T037. T-E5 treatment statistically increased cucumber plant biomass in soil and hydroponic experiments. Based on TaqMan reverse transcriptase-polymerase chain reaction, the population of T-E5 was almost ten times higher than SQR-T037 in the soil samples at 30 days. The endophytic colonization of roots and stems by the two strains had the same dynamic tendency, but T-E5 was much greater than SQR-T037 at any sampling time. The putative mutant T-E5 enhanced the production of IAA and plant colonization ability, and this improvement had a great potential for further application of T-E5 in crop production.

Modulation of Tomato Response to Rhizoctonia solani by Trichoderma harzianum and Its Secondary Metabolite Harzianic Acid.

Abstract: The present study investigated the transcriptomic and metabolomic changes elicited in tomato plants (Solanum lycopersicum cv Micro-Tom) following treatments with the biocontrol agent T harzianum strain M10 or its secondary metabolite harzianic acid (HA), in the presence or absence of the soil-borne pathogen Rhizoctonia solani Transcriptomic analysis allowed the identification of differentially expressed genes (DEGs) that play a pivotal role in plant growth, development and resistance to biotic stress Overall, the results support the ability of T harzianum M10 to activate defense responses in infected tomato plants We observed an induction of hormone-mediated signaling, as shown by the up-regulation of genes involved in the ethylene and jasmonate (ET/JA) biosynthesis Further, the protective action of T harzianum on the host was revealed by the over-expression of genes able to detoxify cells from reactive oxygen species (ROS) Moreover, the over-expression of genes involved in glycolysis, tricarboxylic acid cycle (TCA) and photosynthesis help to understand how this strain promotes plant growth and development On the other hand, HA treatment also stimulated tomato response to the pathogen by inducing the expression of several genes involved in different defense mechanisms (including protease inhibitors, resistance proteins like CC-NBS-LRR) and activating ET/JA- and salicylic acid (SA)-mediated signaling pathways The accumulation of steroidal glycoalkaloids caused by either T harzianum or purified HA, as determined by metabolomic analysis, confirmed the complexity of the plant response to beneficial microbes in terms of secondary metabolism involved in defense mechanisms against pathogens

Transformation of Trichoderma harzianum by high-voltage electric pulse

Abstract: We have developed conditions for an efficient method of genetic transformation in Trichoderma harzianum, using high-voltage electroporation. Transformation was obtained with a plasmid carrying the Escherichia coli, hygromycin B phosphotransferase gene as a dominant selectable marker, and the gpd promoter and trpC terminator from Aspergillus nidulans. The transformation frequency is up to 400 transformants per μg of plasmid DNA. The transformants were phenotypically 100% stable; they were also mitotically stable. Hybridization experiments suggest that the transforming DNA might be integrated at the same position in the T. harzianum genome. This report opens possibilities for improving transformation systems that have already been described for fungi, or else for transforming filamentous fungi where the use of polyethylene glycol is not efficient.

In-vitro inhibition of growth of some seedling blight inducing pathogens by compost-inhabiting microbes

Abstract: Compost-inhabiting bacteria were studied for their effect on seedling blight inducing pathogens. Aspergillus niger, Trichoderma harzianum, Bacillus cereus and Bacillus subtilis were the microbes found associated with cow dung, sawdust and rice husk composted soils. Sclerotium rolfsii, Fusarium oxysporum, Pythium aphanidermatum and Macrophomina phaseolina were isolated from blighted seedlings of Cowpea, while S. rolfsii, P. aphanidermatum, Helminthosporium maydis and Rhizoctonia solani were isolated from blighted maize seedlings. When these compost-inhabiting microbes were paired with the seedling blight inducing pathogens, T. harzianum grew on the mycelia of all the test fungal pathogens. B. cereus reduced the mycelia growth of Sclerotium rolfsii, F. oxysporum, P. aphanidermatum, H. maydis and R. solani, with inhibitory zones ranging from 35.5% to 53.3%. B. subtilis in culture also inhibited the mycelia growth of all tested pathogenic fungi with inhibitory zones of between 40.0% to 57.8%. The inhibitory activities of the compost-inhabiting microbes might partly be responsible for the efficacy of compost in reducing seedling blight diseases of crops. (African Journal of Biotechnology: 2003 2(6): 161-164)