Biological control of root rot disease-causing Rhizoctonia solani in tomato plant by an endophytic fungus and analysis of growth promoting activities in greenhouse and field

Endophytic bacteria improve plant growth and biological control properties. An endophyte, Paecilomyces formosus ED isolated from tomato plant exhibited growth-inhibiting activity against Rhizoctonia solani (67.4 & PLUSMN; 2.2%), Fusarium oxysporum (65.3 & PLUSMN; 3.5%), Rhizopus oryzae (64.8 & PLUSMN; 0.25%), Rhizopus stolonifer (59.2 & PLUSMN; 4.1%), Fusarium verticillioides (42.1 & PLUSMN; 2.1%), Botrytis cinerea (38.3 & PLUSMN; 4.2%), and Fusarium graminearum (15.4 & PLUSMN; 1.1%). The culture filtrate of P. formosus ED showed pronounced inhibitory activity against R. solani. Leaf detached assay exhibited inhibitory activity in tomato leaves treated with fungal spores at 108spores/mL concentration controlling the development of disease symptoms. The endophytic strain ED produced hydrolytic enzymes (chitinase, cellulase, and protease) and these enzymes can cause damage and degradation of pathogenic fungi cell walls. Greenhouse experiment revealed improving plant growth-promoting activity of P. formosus ED in tomato seedlings. The endophyte exhibited phosphate and zinc solubilisation activity and produced indole acetic acid. The disease control effect of P. formosus ED on tomato plants was analyzed in the greenhouse. The endophyte exhibited disease biocontrol activity and reduced disease severity in tomato plant (p < 0.05). Our findings reveal that endophytes could be a novel source of biocontrol agents to be applied in integrated pest management strategies.