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bioRxiv · 10.1101/2024.01.11.575168

The Zymoseptoria tritici avirulence factor AvrStb6 accumulates in hyphae close to stomata and triggers a wheat defense response hindering fungal penetration

Alassimone, J.·Praz, C.·Lorrain, C.·de Francesco, A.·Carrasco-Lopez, C.·Faino, L.·Meile, L.·Sanchez-Vallet, A.
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Abstract

Zymoseptoria tritici, the causal agent of septoria tritici blotch, is one of Europes most damaging wheat pathogens, causing significant economic losses. Genetic resistance is a common strategy to control the disease, Stb6 being a resistance gene used for over 100 years in Europe. This study investigates the molecular mechanisms underlying Stb6-mediated resistance. Utilizing confocal microscopy imaging, we identified that Z. tritici epiphytic hyphae mainly accumulates the corresponding avirulence factor AvrStb6 in close proximity to stomata. Consequently, the progression of AvrStb6-expressing avirulent strains is hampered during penetration. The fungal growth inhibition co-occurs with a transcriptional reprogramming in wheat characterized by an induction of immune responses, genes involved in stomata regulation, and cell wall-related genes. Overall, we shed light on the gene-for-gene resistance mechanisms in the wheat - Z. tritici pathosystem at the cytological and transcriptomic level, and our results highlight that stomata penetration is a critical process for pathogenicity and resistance.

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Alassimone, J., Praz, C., Lorrain, C., de Francesco, A., Carrasco-Lopez, C., Faino, L., Meile, L., Sanchez-Vallet, A.. 2024-01-11. The Zymoseptoria tritici avirulence factor AvrStb6 accumulates in hyphae close to stomata and triggers a wheat defense response hindering fungal penetration. https://doi.org/10.1101/2024.01.11.575168

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