Biocontrol and growth enhancement potential of two endophytic Trichoderma spp. from Terminalia catappa against the causative agent of Common Bean Root Rot (Fusarium solani)

Root rot disease, caused by the fungus Fusarium solani is an important soil-borne disease reducing common bean (Phaseolus vulgaris L.) production yields at up to 84%. The present study aimed at investigating the promotion of common bean seed germination and plant growth, and the biocontrol potential of two endophytic Trichoderma spp. against F. solani. The antagonistic and promotion effects of the endophytic fungi were evaluated by means of in vitro and in vivo experiments. The results achieved showed that the two Trichoderma spp. could exert over 86% and 27% inhibition of F. solani growth and spore germination respectively. The culture filtrate of Trichoderma atroviridae at 50% (v/v) also highly reduced F. solani mycelia growth and spore germination up to 80% and 100% respectively. The ethyl acetate extract of T. atroviridae showed a Minimum Inhibitory Concentration (MIC) of 0.66 mg/mL against F. solani germination. T. atroviridae showed high potential in promoting bean seed germination (100%) at 2 × 105 conidia/mL and in protecting bean seed from the deleterious effects caused by F. solani. In addition, T. atroviridae boosted the germination of bean seed by 20% when treated with 4 × 105 conidia/mL of F. solani, emphasizing its significant biocontrol potential in vitro. It was also less susceptible to resistance development by F. solani. Finally, T. atroviridae significantly reduced the disease severity and incidence by 11.42% and 40% respectively, and also improved growth parameters of bean plant. The results achieved in this study suggest further feasibility studies into using T. atroviridae to express growth promotion in plants for enhanced crop productivity, and to manage root rot disease.