Abstract

Treating Euphorbia pekinensis suspension cultures with endophytic fungal elicitor fromFusarium sp. E5 resulted in accumualtion of isoeuphpekinensin and euphol, activated defense-related enzymes, and increased biomass. The elicitor was prepared from extract of fungal endophyte Fusarium sp. E5 mycelium, and added into 21 day-old cell suspension cultures. The results showed that the biomass of culture after elicitor treatment was increased by 19.35%, whereas the isoeuphpekinensin and euphol contents were 5.81 and 3.56 times greater than those of the control, respectively. The activity of 1-deoxy-D-xylulose 5-phosphate synthase (a key enzyme of isoeuphpekinensin biosynthesis) was not increased significantly, while the activity of 3-hydroxy-3-methylglutaryl coenzyme A reductase (a key enzyme of euphol) was increased by 1.67-fold compared with the control.Furthermore, the elicitor enhanced intracellular and extracellular polyphenol production and the activities of phenylalanine ammonia-lyase, peroxidase and catalase, therefore improved the plant defense ability. In addition, the nuclei of elicitor-treated cells were not apoptotic, and the culture was consistently healthy with increasing biomass. Our results demonstrate that endophytic fungal elicitor promotes both terpenoid biosynthesis and biomass of plant cultures for the first time, and thereby the information from this study will be helpful for large-scale medicinal plant suspension culture.

Key words: Euphorbia pekinensis, endophytic fungal elicitor, terpenoids, Fusarium.