FABI celebrated the successful completion of Dr Trystan Nadasen’s PhD journey on 28 October when he presented his Prestige Seminar “Transcriptomics and structural phylogenetics reveals cell death-inducing effectors in the latent necrotrophic pathogen Cercospora zeina of maize”. Trystan had already graduated at the recent University of Pretoria Spring Graduation.
The supervisors for his PhD were Prof. Dave Berger, and Prof. Ingo Hein of the University of Dundee and James Hutton Institute, Scotland. The external examiners were Dr Jason Rudd (Rothamsted Research](https://www.rothamsted.ac.uk), UK), Dr Matt Helm (Purdue University and USDA, USA) and Dr Farhahna Allie (University of Johannesburg) – who also attended Trystan’s Prestige Seminar.
Prof. Dave Berger said that it had been an absolute pleasure to supervise Trystan, who was mentorship student before completing his Honours, Masters and now PhD in the MPPI research group. He also said that Trystan had a keen sense of responsibility and had contributed a lot to the research group, the Department of Plant and Soil Sciences, and FABI where he was the recipient of a Mentorship Award.
For his PhD, Trystan used RNA sequencing to uncover the previously unknown molecular strategies C. zeina uses to cause gray leaf spot in maize. His research revealed that the fungus acts as a "latent necrotroph," deploying distinct effector proteins at specific infection stages to successfully colonize host tissues. Transient expression via Agrobacterium-mediated transformation in tobacco confirmed that selected effectors modulate plant immune responses.
In another major component of his PhD, Trystan used the AI-based software AlphaFold to model the structures of C. zeina effectors. By analysing conserved structural "folds" instead of amino acid sequences, he identified and validated novel fungal effectors that trigger plant cell death. Trystan’s approach established a powerful framework for discovering fungal virulence proteins, ultimately paving the way for breeding disease resistant crops.