The Zymoseptoria tritici Avirulence Factor AvrStb6 Accumulates in Hyphae Close to Stomata and Triggers a Wheat Defense Response Hindering Fungal Penetration

• DOI: 10.1094/mpmi-11-23-0181-r
• Publication Date: 2024-01-24T13:50:26Z
• Authors: Julien Alassimone; Coraline Praz; Cécile Lorrain; Agustina De Franc...; Cristian Carrasco...; Luigi Faino; Ziqi Shen; Lukas Meile; Andrea Sánchez-Va...
• Keywords: wheat fungal pathogen; Virulence Factors; Wheat fungal pathogen; Hyphae; Plant resistance; gene-for-gene interaction; Microbiology; Fungal Proteins; transcriptomics; Ascomycota; Gene Expression Regulation, Plant; Transcriptomics; Triticum; Plant Diseases; Disease Resistance; Plant Proteins; stomatal-mediated resistance; Stomatal-mediated resistance; Virulence; Botany; plant resistance; QR1-502; gene-for-gene interaction; plant resistance; Septoria tritici blotch; stomatal-mediated resistance; transcriptomics; wheat fungal pathogen; QK1-989; Plant Stomata; Host-Pathogen Interactions; Septoria tritici blotch; Gene-for-gene interaction

Zymoseptoria tritici, the causal agent of Septoria tritici blotch, is one of Europe's 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 more than 100 years in Europe. This study investigates the molecular mechanisms underlying Stb6-mediated resistance. Utilizing confocal microscopy imaging, we determined that Z. tritici epiphytic hyphae mainly accumulate 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 stomatal 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 stomatal penetration is a critical process for pathogenicity and resistance. [Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .