The Screening and Identification of the Biological Control Fungi Chaetomium spp. against Wheat Common Root Rot.

Bipolaris sorokiniana is a soil-borne fungal pathogen, causing common root rot in wheat, and is difficult to control through chemical and agricultural means. Chaetomium spp. have been documented as potential biological control agents for plant diseases. In this study, seven Chaetomium strains were screened for their abilities to control Bipolaris sorokiniana on agar plates. Strain 22-10 significantly inhibited the growth of B. sorokiniana on PDA plates up to 66.7%. Its filtrate of liquid culture also inhibited the mycelial growth of B. sorokiniana, indicated that strain 22-10 produced the secondary metabolites against B. sorokiniana. The severity and disease indexes of common root rot significantly decreased in wheat after treatment with the crude extract of strain 22-10. Six active compounds were purified from crude extract of this fungus culture based on active-driven strategy against B. sorokiniana. Chaetoviridin A showed the highest efficiency to inhibit the growth of B. sorokiniana. Strain 22-10 was identified as C. globosum based on the phylogenetic analysis of rDNA ITS region and microscopic characteristics. The high control efficiency of strain 22-10 of C. globosum against B. sorokiniana suggested has its potential to be biocontrol agent for B. sorokiniana.