ABSTRACT
A macrolide antibiotic, lasiodiplodin was isolated from the endophytic fungus (EF) Lasiodiplodia pseudotheobromae J-10 associated with the medicinal plant Sarcandra glabra. In vitro antifungal assay demonstrated the inhibitory activity of lasiodiplodin against the growth of six phytopathogenic fungi, with the IC50 values ranging between 15.50 and 52.30 µg/mL. The highest antifungal activities were recorded against Exserohilum turcicum, Colletotrichum capsici, and Pestalotiopsis theae, with IC50 values of 15.50, 15.90, and 17.55 µg/mL, respectively. The underlying mechanism of the antifungal activity of lasiodiplodin against E. turcicum included the alteration of its colony morphology and disturbance of its cell membrane integrity. In addition, the optimization of L. pseudotheobromae J-10 culture conditions increased lasiodiplodin yield to 52.33 mg/L from 0.59 mg/L at pre-optimization. This is the first report on the isolation and identification of antifungal compound from the EF L. pseudotheobromae J-10 associated with S. glabra, as well as on the optimization of L. pseudotheobromae J-10 culture conditions to increase lasiodiplodin yield. The results of this study support that lasiodiplodin is a natural compound with high potential bioactivity against phytopathogens, and provide a basis for further study of the EF associated with S. glabra.