Abstract:To investigate the diversity of endophytics in medicinal plant Portulaca oleracea and explore potential biological resources to prevent and control crop diseases, the endophytes from its roots, stems and leaves were isolated by medium cultivation method, their bioactivities were evaluated against Ralstonia solanacearum, and they were identified by colonial morphology and ITS sequence. The results showed that the crude extracts of two endophytics Penicillium citrinum and P. polonicum displayed strong activities against the phytopathogen R. solanacearum. One of active metabolite (citrinin) was identified based on UPLC-QTQF-MS. Moreover, the activity of citrinin had more strong antibacterial property than that of streptomycin, which was a common agent in agriculture to prevent bacterial wilt. So, these would provide scientific basis for biological control of bacterial wilt.