Plant cell walls as a battleground in plant-pathogen co-evolution
Cristian Carrasco-López (Spain)1; Sergio López-Cobos (Spain)1; Diego Rebaque (Spain)2; Felipe De Salas (Spain)3; Meriem Aitouguinane (Spain)4; Antonio Molina (Spain)4; Hugo Mélida (Spain)5; Maria Jesús Martínez (Spain)6; Andrea Sánchez-Vallet (Spain)7;
1 - Centro de Biotecnología y Genómica de Plantas (CBGP/UPM/INIA-CSIC), Madrid, España; 2 - Universidad de León; 3 - Centro de Investigaciones Biológicas Margarita Salas, Spanish National Research Council,; 4 - Centro de Biotecnología y Genómica de Plantas (CBGP/UPM/INIA-CSIC); 5 - Área de Fisiología Vegetal, Departamento de Ingeniería y Ciencias Agrarias, Universidad de León; 6 - Centro de Investigaciones Biológicas Margarita Salas, Spanish National Research Council; 7 - Centro de Biotecnología y Genómica de Plantas (CBGP/UPM/INIA-CSIC). Spanish Research Council;
Keywords: Plant cell wall modifying enzymes (CWMEs); The molecular arms race between plants and pathogen; Cell wall-derived elicitor;
Abstract Topics: Theme 9: Cell Wall Function and Signaling in plant adaptation to Biotic and Abiotic Stresses
Type of Presentation: Oral Communication

Abstract text: Plant cell walls constitute a central battleground in the molecular arms race shaping plant–pathogen interactions. Pathogens deploy hydrolytic enzymes to breach plant cell walls, whereas plants perceive cell wall damage through sophisticated surveillance mechanisms. The mechanisms by which pathogens evade host recognition remain mostly unknown. Here, through integrated transcriptomic, genetic and biochemical analyses, we identify key enzymes from the fungal plant pathogen Zymoseptoria tritici that target wheat cell walls and prevent host recognition. ZtGH45, a β-glucanase, degrades mixed linked glucans and releases elicitors of the immune response. To avoid premature detection, Z. tritici produces this enzyme only at late stages of infection. ZtABF1, an α-L-arabinofuranosidase, contributes to nutrient acquisition and degradation of an immune-activating arabinoxylan-derived oligosaccharide. In addition, two mannan-degrading enzymes, ZtMan5 (endo-β-mannanase) and ZtMan2 (exo-β-mannanase), are co-expressed during infection. ZtMan5 depolymerizes mannan and releases mannan-derived elicitors of the host immunity, while ZtMan2 further degrades these oligosaccharides and prevents recognition. Together, our results reveal a coordinated strategy in which Z. tritici employs tightly regulated enzymes to prevent recognition by the host. Consequently, plant cell walls emerge as critical for the outcome of plant-pathogen interactions and pathogen evolution.