Abstract: In order to obtain the antagonistic fungi with good antagonistic effect on Fusarium cugenangense, fungal strains were isolated from the rhizosphere soil of tea plants with root rot infection by dilution coating plate method, and a strain with high antagonistic activity was screened by plate confrontation method and identified based on morphological observation and ITS sequence analysis methods. The disease prevention and growth promotion property, inhibition spectrum, and inhibition activity of volatile and non-volatile metabolites were determined. The inhibition ability of fermentation broth of antagonistic strain against F. cugenangense was evaluated. The results showed that a strain CA5 with high inhibitory effect on tea root rot pathogen was obtained and identified as Talaromyces pinophilus. Its plate inhibition rate against F. cugenangense was 77.39%. The strain CA5 had the ability to produce cellulase, β-1,3 glucanase and chitinase, and also had inorganic phosphorus and organophosphate solubilities, potassium solubility and nitrogen fixation capacities, as well as the ability to produce siderophore, IAA and ammonia. Inhibition rates of strain CA5 on other 8 plant pathogens were all greater than 60%. Inhibition rates of volatile and non-volatile metabolites on mycelial growth of tea root rot pathogen were 14.90% and 44.33%, respectively. Inhibition rates of fermentation broth, suspension and sterile fermentation filtrate on mycelial growth of tea root rot pathogen were 73.42%, 67.32% and 25.75%, respectively. Pot experiment showed that the control efficacy against tea root rot disease was 56.11%, and the strain had a promoting effect on the growth of tea seedlings. In conclusion, the strain CA5 has great application potential in the prevention and control of tea root rot.

Key words: tea plant, root rot, Talaromyces pinophilus, growth promotion, biological control