Identification and inhibition effect of antagonistic Trichoderma strain TB72 against Thielaviopsis basicola.
A Trichoderma strain TB72 which can inhibit the pathogen of tobacco black root rot intensively was isolated and screened from the rhizospheric soil of tobacco fields. In order to evaluate scientifically the biocontrol potential of strain TB72 against tobacco black root rot, by pairing culture on PDA plate, inhibiting the pathogen, disease controlling test and taxonomic identification with cultural character, morphological characteristics and molecular methods, the results showed that the Trichoderma strain TB72 exhibited significantly antifungal activities against Thielaviopsis basicola, the pathogen of tobacco root rot, and the inhibitory effect reached 52.3% by pairing culture on PDA plate. It was found that the effect of strain TB72 on reduction the incidence of tobacco black root rot, the control efficacy reaching to 84.5% in a greenhouse experiment. And the results of inhibiting the pathogen showed that culture filtrate of TB72 was effective for inhibiting mycelium growth and reducing spore germination of T. basicola. According to the characteristics of cultural, morphological, as well as sequence analysis of the internal transcribed spacer region of the ribosomal DNA(ITS), the strain TB72 was identified as Trichoderma asperellum.