Characterization of Novel Brazilians Rhizosphere Soil Trichoderma spp. to Select Effective Biocontrol Agents against Sclerotinia sclerotiorum on Beans

Abstract

Trichoderma spp. are fungus considered one of the most attractive for biological control due to its different mechanisms action against plant pathogens and action to promote plant growth and productivity. The molecular characterization of this group of antagonists is of great importance for conducting studies in the area of biodiversity and for identifying and selecting the possibility of their use in biological control. Objective of this work was to identify 29 Trichoderma isolates based on molecular profiles and phylogenetic analysis sequence the rRNA gene ITS1-5-8S-ITS2, as well as to select the isolates that presented the highest levels of antagonism against S. sclerotiorum and that promoted growth in common bean using experiments in vitro and in a greenhouse. Among the sequences obtained, a total of five different Trichoderma species were identified: T. asperellum, T. harzianum, T. koningiopsis, T. brevicompactum and T. tomentosum. The Trichoderma isolates used showed a variation in the mycelial inhibition of the pathogen by non-volatile metabolites between 84.11% to 100%. Regarding the dry weight of the plants treated with Trichoderma and the pathogen, it was observed that ten Trichoderma isolates promoted plant growth in relation to the control with a variation of 2.6% to 34%. T. asperellum CEN201 proved to be the best candidate to participate in a broader selection that would include field tests for the biological control of S. sclerotiorum and growth promotion in common bean, as in the laboratory and at home of vegetation showed great success in inhibiting the pathogen and promoting plant growth.