Trichoderma species is a heterotrophic saprobion organism, which competes with other microorganisms, preventing them from developing. This fungus has mechanisms of action, among which are: production of antibiotics and metabolites, and hyperparasitism, which also promotes the induction of systemic resistance in plants. In this study, five native Trichoderma strains which were collected from agricultural land in Tamaulipas, Mexico were evaluated. The objective of this research was to identify the secondary metabolites produced by native strains of Trichoderma spp. under in vitro conditions and evaluation of the effect of these compounds on the growth of the pathogen Fusarium oxysporum and the germination of tomato seeds (Solanum esculentum). The production of Trichoderma's metabolites was performed by culturing in 150 ml of potato broth supplemented with sucrose (5%) and yeast extract (5%). Inoculation was performed by the addition of a 4 mm disk of active mycelium and allowed to grow at 25C ± 2°C and 12 h light/dark on a rotary shaker at 150 rpm for three weeks. Subsequently, the extraction of metabolites was performed using liquid: liquid phase which consisted of the filtrate and methylene chloride in a ratio of 1:3, and then the organic phase was recovered. The organic fraction was evaporated at 40°C with the aid of a rotary evaporator (Buchi®); the sample was recovered in 1 ml of methylene chloride. Analysis by GC-MS indicates that Trichoderma isolates produced 41 secondary metabolites of volatile and semi-volatile molecules and was observed, such that the number of compounds varies from the species analyzed and the collection site. The evaluation of the antagonistic activity of the extracts of Trichoderma spp. on F. oxysporum showed no significant differences between treatments (P=0.05); however, it was observed that pigmentation decreased in the mycelium of the pathogen. Regarding the evaluation of the effect of the extracts on the seeds of tomato, it was observed that the compounds of Trichoderma asperellum (TV1) induced the germination and the development of the seedling.

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Antifungal activity of water, ethanol, lanolin and cocoa butter plant extracts derived from seven Mexican Chihuahuan desert inhabiting plant species (Larrea tridentata, Flourensia cernua, Agave lechuguilla, Opuntia ficus-indica, Lippia graveolens, Carya illinoensis and Yucca filifera)were evaluated against Phytophthora cinnamomi. All plant extracts were active against Phytophthora cinnamomi. Two (L. tridentata and F. cernua) out of seven plant species tested had the optimal antifungal activity against this fungus specie, with minimum inhibitory concentration (MIC) values as low as 6.96 and 8.6 mg/L. Some of the plant extracts had moderate to low activity against P. cinnamomi, and the variations of active polyphenolic (condensed and hydrolysable tannins) compounds in the plant extracts estimated via colorimetric methods indicated that the inhibitory activity may not based on a general metabolic toxicity but perhaps the antifungal potency is conferred by group or groups of toxic metabolites. Based on the antifungal activity, crude plant extracts may be a cost effective way of protecting crops against P. cinnamomi. Because plant extracts contain several antifungal compounds, the development of resistant pathogens to these plant extracts may be delayed.