Group Leader Max Planck Institute for Biology Tübingen, Baden-Wurttemberg, Germany
Wheat blast, caused by the ascomycete blast fungus Magnaporthe oryzae, is an emerging and devastating threat to wheat production worldwide. Wheat blast was first reported in Brazil (BR) 40 years ago, followed by more recent outbreaks in Bangladesh (BD) and Zambia (ZM). Magnaporthe oryzae displays a compartmentalized and dynamic genome, with presence-absence and structural variation in supernumerary mini-chromosomes (mChrs) driving genomic rearrangements, segmental duplications and copy number variation (CNV) of virulence-related genes. While isolates of the S. American wheat blast fungus founder population only contained 7 core chromosomes, modern wheat blast isolates carry one or more mChrs and exhibit increased virulence, suggesting a possible role of mChrs during infection. However, the impact of mChr-mediated structural and copy-number variation on virulence and reproductive success remains largely unknown. In this study, we integrate infection stage-specific RNA-seq and confocal microscopy to perform a comparative transcriptome analysis of M. oryzae isolates from different geographical backgrounds (BR, BD, ZM) and with varying mChr content (0, 1, and 2 mChrs) during wheat and barley infection. Our study will provide valuable insights into how genome structure impacts the expression of virulence-related genes during host-specific infection, advancing our understanding of wheat blast evolution and pathogenesis.
