Abstract

Biotic inducing agents such as Trichoderma spp. are an alternative for the induction of resistance by activating defense mechanisms of plants. This work aimed to study the interaction between bean and Trichoderma spp. evaluating the effects of the induction of resistance in bean through the defense enzymes activity and ability to endofitism. The experimental was design in randomized blocks, with four replications, being 21 isolates of Trichoderma spp. and control. The isolates were inoculated at planting, with adding 0.8 ml of the suspension 1×10⁸ conidia/ml in groove, in sterilized soil. After 30 days, leaf and roots samples were taken to determine the enzyme activity. To verify the endophytic colonization capacity of isolated, bean root fragments were sanitized and placed in Petri dishes containing PDA medium. Data were submitted to analyzes of variance and compared by Scott-Knott test (p<0.05). The enzymatic activity of peroxidase, polyphenoloxidase and phenylalanine ammonia-lyase was not significant, but the β-1-3-glucanase activity in leaf tissue was suppressed by isolates TI1, TM1, TLB15 (Trichoderma virens), TI2, TLB3, TLB4, TLB12, TOD1, TOD3 (Trichoderma harzianum), TLB6 (Trichoderma asperellun), TLB14, TLB17 (Trichoderma koningiopsis) and TOD2B (Trichoderma longibrachiatum). The isolates TM4, TLB9, TLB15 (T. virens), TI2, TI4, TLB2, TOD1 (T. harzianum) and TLB17 (T. koningiopsis), were able to colonize endophytically the bean roots. Trichoderma has endophytic capacity and interfere in β-1-3-glucanase activity.

Key words: Induced resistance, Phaseolus vulgaris L., Trichoderma spp.