Trichoderma sp. was the most interesting fungus isolated during this research of the Angangueo mining zone microflora. We accept its importance because when Trichoderma grew in a media containing copper, showed a growing pattern characteristic of a dosis-response curve and inhibited at 200 ppm of copper, nevertheless when Trichoderma was grown in a media containing 400 ppm the growing pattern was recovered to stop again at 800 ppm.

    The surviving strains at 400 ppm of copper were re-grown, the analysis of subsequent generations from this strains showed some methabolical and morphological differences, for example, the resistence pattern were not only still active but reinforced, the fungus became copper dependient, as it can be seen when the new copper-dependient generation grew weakly in a media containing 50 ppm, situation seen again when growing at 100 ppm of copper but when growing in media with 200 ppm of copper (where the wild strain showed the Minimal Inhibitory Concentration) the growing diameter was similar to control. This new strain showed a resistance signal at 400 ppm of copper.

    A notorious change in the pigmentation pattern of the strains tested after growing in a media containing a certain heavy metal concentration is an important characteristic, as well as the surge of a pseudoyeast cycle. The analysis of the pigment synthesized by this adapters suggests that is an anthocyanin also synthesized during heavy metal induced mutations in maize. The discovered pseudoyeast cycle of Trichoderma was result of the spore aggregation and the genetic material interchange. The spores harvested are copper dependient just like the resistant strain.
 

Go to heavy metal induced changes in fungus strains.

Contaminación por metales pesados y su influencia en la evolución.