Antifungal activity of metabolites of the endophytic fungus Trichoderma brevicompactum from garlic.

The endophytic fungus strain 0248, isolated from garlic, was identified as Trichoderma brevicompactum based on morphological characteristics and the nucleotide sequences of ITS1-5.8S- ITS2 and tef1. The bioactive compound T2 was isolated from the culture extracts of this fungus by bioactivity-guided fractionation and identified as 4ß-acetoxy-12,13- epoxy-Δ(9)-trichothecene (trichodermin) by spectral analysis and mass spectrometry. Trichodermin has a marked inhibitory activity on Rhizoctonia solani, with an EC50 of 0.25 µg mL(-1). Strong inhibition by trichodermin was also found for Botrytis cinerea, with an EC50 of 2.02 µg mL(-1). However, a relatively poor inhibitory effect was observed for trichodermin against Colletotrichum lindemuthianum (EC50 = 25.60 µg mL(-1)). Compared with the positive control Carbendazim, trichodermin showed a strong antifungal activity on the above phytopathogens. There is little known about endophytes from garlic. This paper studied in detail the identification of endophytic T. brevicompactum from garlic and the characterization of its active metabolite trichodermin.

Antifungal activity of metabolites of the endophytic fungus Trichoderma brevicompactum from garlic

The endophytic fungus strain 0248, isolated from garlic, was identified as Trichoderma brevicompactum based on morphological characteristics and the nucleotide sequences of ITS1-5.8SITS2 and tef1. The bioactive compound T2 was isolated from the culture extracts of this fungus by bioactivity-guided fractionation and identified as 4β-acetoxy-12,13-epoxy-Δ9-trichothecene (trichodermin) by spectral analysis and mass spectrometry. Trichodermin has a marked inhibitory activity on Rhizoctonia solani, with an EC50 of 0.25 µgmL-1. Strong inhibition by trichodermin was also found for Botrytis cinerea, with an EC50 of 2.02 µgmL-1. However, a relatively poor inhibitory effect was observed for trichodermin against Colletotrichum lindemuthianum (EC50 = 25.60 µgmL-1). Compared with the positive control Carbendazim, trichodermin showed a strong antifungal activity on the above phytopathogens. There is little known about endophytes from garlic. This paper studied in detail the identification of endophytic T. brevicompactum from garlic and the characterization of its active metabolite trichodermin.

Isolation and functional analysis of Thmfs1, the first major facilitator superfamily transporter from the biocontrol fungus Trichoderma harzianum.

A novel major facilitator superfamily (MFS) transporter gene, Thmfs1, was isolated from Trichoderma harzianum (T. harzianum). A Thmfs1 over-expressing mutant displayed enhanced antifungal activity and fungicide tolerance, while the Thmfs1 disruption mutant showed the opposite trend. Trichodermin production in Thmfs1 disruption group (185 mg l(-1)) was decreased by less than 17 % compared to the parental strain, suggesting that Thmfs1 is not mainly responsible for trichodermin secretion. Real-time PCR showed that Thmfs1 transcript level could be induced by a certain range of trichodermin concentrations, while expression of Tri5, encoding a trichodiene synthase, was strongly inhibited under these conditions. To our knowledge, Thmfs1 is the first MFS transporter gene identified in T. harzianum.

Trichothecenes induce accumulation of glucosylceramide in neural cells by interfering with lactosylceramide synthase activity.

Trichothecenes are sesquiterpenoid metabolites produced by several fungal strains that impair human and animal health. Since sphingolipids were connected with fungal toxicity the aim of the present study was to test the influence of fungal metabolites on sphingolipid metabolism in neural cells. The crude extract of fungal strain Spicellum roseum induced accumulation of glucosylceramide (GlcCer), and simultaneous reduction of the formation of lactosylceramide (LacCer) and complex gangliosides in primary cultured neurons. Following a bioassay-guided fractionation of the respective fungal extract we could demonstrate that the two isolated trichothecene derivatives, 8-deoxy-trichothecin (8-dT) and trichodermol (Td-ol) were responsible for this effect. Thus, incubation of primary cultured neurons as well as of neuroblastoma B104 cells for 24 h with 30 microM of either of the two fungal metabolites resulted in uncoupling of sphingolipid biosynthesis at the level of LacCer. For the observed reduction of LacCer synthase activity by about 90% cell integrity was crucial in both cell types. In neuroblastoma cells the amount of LacCer synthase mRNA was reduced in the presence of trichothecenes, whereas in primary cultured neurons this was not the case, suggesting a post-transcriptional mechanism of action in the latter cell type. The data also show that the compounds did not interfere with the translocation of GlcCer in neuroblastoma cells. Collectively, our results demonstrate that trichodermol and 8-deoxy-trichothecin inhibit LacCer synthase activity in a cell-type-specific manner.

[Influence of Bacillus intermedius RNAse on growth-stimulating and antagonistic characteristics of Trichoderma harzianum]. / Vliianie rnkazy Bacillus intermedius na roststimuliruiushchie i antagonisticheskie svor'stva Trichoderma harzianum.

Bacillus intermedius RNAase (with specific activity of 1,000,000 units per one mg of protein) at concentration of 1 x 10(-3) mg/ml was shown to increase antagonistic and growth-stimulating properties of Trichoderma harzianum. An application of trichodermin which was treated with an enzyme enhanced cucumber crop capacity by 15-18% in industrial conditions.