Abstract

A new endophytic strain of Paraconiothyrium brasiliens LT161 was isolated from the healthy stems of Cinamonum camphora collected from Nanjing, China, and was identified based on morphological characteristics and internal transcribed spacer (ITS) sequence analysis. The culture filtrate and its ethyl acetate extract of strain LT161 showed strong growth inhibition activity in vitro against fungal phytopathogens such as Rizoctonia solani, Alternaria alternate, Glomerella glycines, Phytophthora capsici, Fusarium oxysporum, Fusarium graminearum and Cryphonectria parasitica. The bioactive metabolites in the filtrate were relatively thermally stable, but sensitive to strong alkaline conditions. Simulation test within the dish indicated that the bioactive composition of strain LT161 pose considerable ability in controlling rice sheath blight disease, Fusarium root rot and wheat Alternaria leaf blight. The antifungal compounds in the filtrate of strain LT161 might be novel based on liquid chromatography/mass spectrometry (LC/MS) analysis and comparison to the Syngenta natural product dereplication database. These results suggest that the strain LT161 could be a promising candidate for producing leading compound of pesticide development or used directly as biological control agent in the sustainable agriculture system.

Key words: Paraconiothyrium brasiliens, antifungal activity, biological control, endophytic fungi.