This chapter discusses the thermotolerant agriculturally important microorganisms, which play a pivotal role in improving crop performance under thermal stress conditions and diminish the effect of heat stresses on plants through production of exopolysaccharates and biofilm formation. These beneficial microorganisms include plant growth-promoting rhizobacteria, rhizosphere-competent fungi of the genus Trichoderma and arbuscular mycorrhiza fungi.

This chapter discusses Trichoderma biodiversity and potent isolate identification for applying as a biological control agent. The main modes of action of Trichoderma spp. are described, i.e. mycoparasitism of fungal pathogens with subsequent release of cell-wall-degrading enzymes such as cellulases, glucanases, chitinases, etc., and antibiosis by secretion of antimicrobial secondary metabolites and competition for nutrients. The application of Trichoderma spp. as biofertilizers is also discussed. Commercial formulations of Trichoderma spp. are described, and future prospects are mentioned.