IBH Seminar: Cross-kingdom RNA communication in the barley-powdery mildew interaction

The International Barley Hub is pleased to announce the next in the 2024 series of seminars: ‘Cross-kingdom RNA communication in the barley-powdery mildew interaction’ presented by Ralph Panstruga (Professor , RWTH Aachen University) and Hannah Thieron (Post-Doctoral Researcher, RWTH Aachen University).

Speakers bio:

Ralph Panstruga

Ralph studied Biology at RWTH Aachen University (Germany), where he also obtained his PhD degree. Thereafter, he spent two years as a post-doc at the Sainsbury Laboratory in Norwich (U.K.) and briefly worked as a post-doc period at the U.L.B. in Brusssels (Belgium). Following a three-year break in academic science, he continued as a post-doc at the Max Planck Institute for Plant Breeding Research in Cologne (Germany), where he subsequently became first a research group leader and then an International Max Planck research group leader. In 2011, he took over a professorship In Plant Molecular Cell Biology at RWTH Aachen University (Germany).

Hannah Thieron

Hannah studied Biology at RWTH Aachen University (Germany). During her Master’s studies she performed a research internship in the lab of Pietro Spanu at Imperial College London (U.K.). For her final project she moved to the Sainsbury Laboratory in Norwich (U.K.). After a 1.5-year break working in industry, she started a PhD in the group of Ralph Panstruga which she completed in 2022 and continued working as a post-doc.


The establishment of host-microbe interactions requires molecular communication between both partners, which may involve the mutual transfer of noncoding small RNAs. Previous evidence suggests that this is also true for the barley powdery mildew disease, which is caused by the fungal pathogen Blumeria hordei. However, previous studies lacked spatial resolution regarding the accumulation of small RNAs upon host infection by B. hordei. We analysed site-specific small RNA repertoires in the context of the barley-B. hordei interaction. To this end, we dissected infected leaves into separate fractions representing different sites that are key to the pathogenic process. Unexpectedly, we discovered enrichment of specific fragments of barley ribosomal RNA in extracellular vesicles and infected epidermis, as well as particular B. hordei transfer RNA fragments in haustoria. We further investigated extracellular vesicles, which are supposed to play a major role in cross-kingdom RNA communication, in more detail. We noted that extracellular vesicles derived from the apoplastic wash fluid of barley leaves constitute polydisperse populations that are selectively responsive to leaf infection by B. hordei. Proteome analysis uncovered an enrichment of biotic stress response proteins associated with the extracellular vesicles. The barley t-SNARE protein Ror2, the ortholog of the PEN1 marker protein of extracellular vesicles in Arabidopsis thaliana, accumulates in extracellular vesicles during powdery mildew infection, hence also qualifying as a potential marker protein.