LongRNAFun: The role of long antisense RNAs in the rapid evolutionary adaptation of the barley powdery mildew pathogen

Stefan Kusch, Post-Doc in PA 861/14-2

Fungal pathogens such as the barely powdery mildew pathogen Blumeria graminis f.sp.
hordei (Bgh) are a major threat to health and food security worldwide. While the cereal
powdery mildew fungi (B. graminis) exhibit remarkably strict host specificity, they rapidly
evolve and overcome plant immunity or even conduct host jumps and host range
extensions. The genomes of powdery mildews including B. graminis are strongly inflated
due to ancient and recent bursts of activity of transposable elements (TEs). I observed that
long spliced RNA molecules that seemingly do not encode any protein are abundantly
transcribed in opposite orientation by TEs in Bgh. These may represent long noncoding
RNAs (lncRNAs) that regulate the expression of TEs. Intriguingly, some of these lncRNAs
also might serve as templates for the evolution of novel genes, which could be involved in
disturbing host defence processes. In the context of this fellowship, I plan to explore
the role of these lncRNAs in Bgh biology. First, I will conduct whole transcriptome
shotgun sequencing (RNA-seq) of Bgh during the major infection stages such as host cell
penetration and haustorium formation, with the aim to generate an annotated catalogue of
these lncRNAs. Then, I will functionally analyze selected lncRNAs up-regulated during
critical infection stages through over-expression and silencing approaches. This study will
shed light on the long-standing question about the function and regulation of the excessive
numbers of TEs in Bgh towards understanding the mechanisms of rapid evolution in this
fungus.