A hearty congratulations to Mandy Messal who is the sixth FABIan to complete their PhD in FABI this year. Mandy presented her Prestige seminar “Fungal community interactions in the Eucalyptus grandis phyllosphere” on 9 June. Her supervisors were Prof. Bernard Slippers, Prof. Sanushka Naidoo and Dr Martin Kemler from the Universität Hamburg in Germany. The external examiners for her thesis were Prof. Åke Olson from the Swedish University of Agricultural Sciences and Prof. Johanna Witzell from Sweden’s Linnæus University with Prof. Noelani van den Berg was the internal examiner for Mandy’s thesis. Prof. Bernard Slippers praised Mandy for taking on a very difficult and complicated project from which she, and the scientific community, learnt a lot and which has moved this field of study forward. Mandy used molecular approaches in a novel and powerful way to analyse the diversity and functions of Eucalyptus-inhabiting fungal communities. Highly diverse and metabolically active communities were discovered in healthy tissues of Eucalyptus trees using metabarcoding and metatranscriptomics data, and these were shown to differ in activity, but not diversity between resistant and susceptible clones. Fungal communities surrounding leaf galls of the insect pest, Leptocybe invasa, were shown to decrease in fungal diversity with increasing insect infestation level. Finally, using a genome wide association study approach, host gene regions were identified which associate with the diversity of its fungal community, paving the way to understanding the interaction between the host and fungal community at a more mechanistic level. This thesis lays a foundation for developing this system into a model for understanding tree-phyllosphere fungal communities.