Endophytic fungi colonize living plant tissues and establish mutually beneficial relationships with their hosts. The closely related endophytes Serendipita indica and Serendipita vermifera inhabit the roots of phylogenetically diverse hosts. In return for gaining access to plant metabolites, they promote the growth of their hosts and protect them against invasion by the pathogenic fungus Bipolaris sorokiniana.

To ensure successful colonization, endophytes secrete small effector proteins. Recently, it has been demonstrated that fungal effectors not only target host cell functions but may also antagonize competing microorganisms.

While more fungal effectors are functionally characterized every year, it is largely unclear how endophytic fungi control the expression of effectors. This project aims to identify transcription factors that regulate the expression of Serendipita effectors in the presence of plant hosts or the competing fungus B. sorokiniana. For this purpose, time-resolved transcriptional profiles of the fungus-host and fungus-fungus interaction are going to be analysed to identify co-regulated effector clusters. Next, Serendipita transcription factors that control the expression of effector genes will be identified via DAP-seq. For promising transcription factor candidates, null-mutants and overexpression lines will be generated to demonstrate their importance for fungus-host or fungus-fungus interactions experimentally.