Travel grants to go - Stefan Kusch

31 May 2019 - By: Stefan Kusch

Travel grants to go - Stefan Kusch

Stefan Kusch
Stefan Kusch. Photo: Lamprinos Frantzeskakis

Stefan travelled to Pacific Grove, California, USA to attend the 30th Fungal Genetics Conference and present his research entitled “Rapid evolutionary adaptation of phytopathogenic powdery mildew fungi to highly selective plant environments”.

Stefan’s research involves analysing the genomics and evolutionary trajectories of the powdery mildew pathogen Blumeria graminis f.sp. hordei (Bgh). Infecting barley, the fungus is of high agronomic importance in Europe.

“The obligate biotrophic ascomycete fungus Blumeria graminis causes the powdery mildew disease on grasses including wheat and barley. Different formae speciales of Blumeria graminis exhibit strict host specificity, e.g. the barley powdery mildew (Blumeria. graminis f.sp. hordei, Bgh) can only complete its pathogenic life cycle on barley, but not on other grasses. We hypothesize that the evolution of the fungus is fast enough to detect changes in its virulence spectrum in real time. To identify the nature of genomic alterations underlying such putative rapid evolutionary adaptations, we generated experimentally evolved Bgh isolates displaying virulence on otherwise fully resistant barley mlo (Mildew locus O) mutant plants. We conducted functional genomics and found a highly volatile genome characterized by copy number variation of effector genes and a recent expansion of transposable elements. We discovered that a gene coding for a transcription factor known to affect virulence and hyphal development is part of a ~40 kb genomic deletion in the virulent Bgh isolate. Further, by RNA-Seq we identified 123 genes that are differentially expressed in this isolate at the time of host cell penetration”, explained Stefan.

Stefan attended the conference to widen his network with experts in fungal genomics and to exchange knowledge and learn about highly relevant aspects regarding his work. “The research program of the Fungal Genetics Conference included a number of excellent plenary talks and concurrent sessions. Most notably I very much enjoyed the presentation of Yi Liu from the University of Texas-Dallas. He introduced the recently published work of his group showing that a codon-optimised human gene, Kras, is not only more efficiently translated, but also more efficiently transcribed than its codon non-optimal counterpart due to codon-dependent histone methylation marks.

The plenary session by Gunther Doehlemann from Cologne University, Germany was also very interesting. He presented the most recent work of his group, characterizing the effector Pit2 from the smut fungus of maize, Ustilago maydis. Pit2 is a substrate of plant Papain-like cysteine proteases (PLCPs), which usually release the peptide Zip1 to trigger plant defense, but are inhibited by the release of the inhibitory domain of Pit2 through PLCP activity. The inhibitory domain alone was sufficient to block PLCP activity.

The conference also enabled me to learn about several approaches and methods in fungal genomics that I can directly implement into my own work and analysis, thus strengthening the impact of my findings. This will allow me to publish my works in prestigious journals in the future.

I discovered numerous studies involving genomics, population genomics, and experimental evolution of diverse fungal lineages including plant beneficial and pathogenic fungi. Due to the fact that genome sequencing has become much more affordable in recent years, many projects now involve a huge sequencing effort of wild fungal populations, addressing questions about their evolution and diversity in an unprecedented scope. I talked to several poster presenters about methods for fungal genome comparison, experiences with long read sequencing and genome assemblies, and challenges when working with obligate pathogenic fungi. Working with powdery mildews, these topics are particularly relevant to me as they present a challenging system: they can neither be cultivated in vitro nor are they amendable for genetic manipulation.

In addition I learned about ways to analyse and visualize differences between genomes. As I am conducting comparative genomics analysis of several plant pathogens (including powdery mildew, but also Sclerotinia species) this was very relevant to me. I learned about the feasibility of assembly techniques, most notably Hi-C, which enables structural improvement of genome assemblies by linkage of local genomic DNA and I am currently working on implementing this method for improving the assembly of a powdery mildew isolate that I am sequencing at the moment.

Overall the atmosphere of this conference was very pleasant and offered numerous opportunities for networking and learning in a relaxed and inviting environment.”

Category: Cell Biology