Poster
Ram Sevak Raja Kumar
Max Planck Institute for Plant Breeding Research
K??ln, Nordrhein-Westfalen, Germany
Stephane Hacquard
MPIPZ
Cologne, GERMANY
Arpan Kumar Basak
Max Planck Institute for Plant Breeding Research
Köln, Nordrhein-Westfalen, Germany
Tak Lee
Max Planck Institute for Plant Breeding Research
Koln, Nordrhein-Westfalen, Germany
Bruno Huettel
Max Planck Institute for Plant Breeding Research
Köln, Nordrhein-Westfalen, Germany
Brigitte Pickel
Max Planck Institute for Plant Breeding Research
Köln, Nordrhein-Westfalen, Germany
Stephanie Carvajal
Max Planck Institute for Plant Breeding Research
Köln, Nordrhein-Westfalen, Germany
Plectosphaerella cucumerina, an ascomycete fungus often described as a necrotrophic fungal pathogen, is one of the most prevalent and abundant fungal taxa that associate with the roots of Arabidopsis (Arabidopsis thaliana) in natural populations across Europe. This project aimed at understanding the fungal genetic determinants driving adaptation to different hosts using transcriptomic, experimental evolution, and reverse genetic approaches. Confocal microscopy showed extensive endophytic colonization in Arabidopsis and Tomato (Solanum Lycopersicum cv Micro-Tom) roots, but only sporadic infection in Barley (Hordeum vulgare L. cv Golden Promise) roots, correlating with a lack of disease symptoms in Barley. Fungal transcriptome analysis revealed unique transcriptional reprogramming in response to Arabidopsis, Tomato, and Barley that mirrored plant cell wall compositions, with up-regulation of genes encoding carbohydrate-active enzymes. CRISPR/Cas9-mediated genome editing showed that glucan-degrading enzyme family GH64 links endophytic colonization to plant health and adaptation to dicot hosts. Experimental evolution of the fungus in response to the three hosts showed that Barley-evolved strains not only gained an advantage at colonizing Barley roots but also became less pathogenic to dicot hosts, without large genetic variations, suggesting non-genetic factors in phenotypic variation. These findings enhance our understanding of fungal strategies for host adaptation in roots.