PhD defence T. (Ting) He

Endophytic fungi of Vinca minor: exploring species and biochemical diversity

Endophytic fungi still remain a relatively under-investigated group of microorganisms, with much of their potential yet to be explored. In this thesis, we focused on the endophytic fungi associated with medicinal plants, as these organisms have captured the attention of researchers in the field for being a promising source of novel bioactive compounds. More specifically, we focused on Vinca minor (lesser periwinkle), belonging to the family of Apocynaceae and popular for its ornamental and medicinal properties. It produces a wide array of vinca alkaloids with neuroprotective and antioxidant bioactivities and was used in folk medicine for the treatment of hypertension, as a carminative, emetic, hemostatic, and astringent, and in the treatment of toothache and snakebite. More than 50 indole alkaloids have been extracted and isolated from V. minor. Its main alkaloid, vincamine is a recognized neuroprotector and cerebral vasodilator, widely used in the pharmaceutical industry. To date, the endosphere microbiome of V. minor remains largely unexplored, rendering it an interesting subject for investigating the diversity and natural products of endophytic fungi. Therefore, we sought to explore the taxonomic diversity among endophytic fungi associated with V. minor based on culture-independent and culture-dependent methods and investigate their natural products.