reviewed the principal mechanisms by which Trichoderma may be an effective biocontrol agent, including interactions that can alter the transcriptome in the host plant, and induce host resistance against pathogens.
Altomare et al.(1999) found that T. harzianum strain T22 could produce soluble forms of manganese, metallic zinc
and calcium phosphatein vitro, and also that the fungus produced metabolites that reduced ferric iron (III) to the ferrous form readily assimilated by plants. Studies by Jalal et al. (1986, 1987) showed that T. virensproduces the siderophores mono- and di-hydroxamates as mechanisms of Fe III chelation. According to these investigators, the conversion of metal oxides to soluble forms by
Trichodermaspp.