Journal Article
The infection cushion of Botrytis cinerea : a fungal ‘weapon’ of plant‐biomass destruction
Mathias Choquer; Christine Rascle; Isabelle R. Gonçalves; Amélie de Vallée; Cécile Ribot; Elise Loisel; Pavlé Smilevski; Jordan Ferria; Mahamadi Savadogo; Eytham Souibgui; Marie‐Josèphe Gagey; Jean‐William Dupuy; Jeffrey A. Rollins; Riccardo Marcato; Camille Noûs; Christophe Bruel; Nathalie Poussereau
Environmental Microbiology · Vol. 23, Issue 4 · pp. 2293-2314 · 2021
Abstract
Summary The necrotrophic plant‐pathogen fungus Botrytis cinerea produces multicellular appressoria dedicated to plant penetration, named infection cushions (IC). A microarray analysis was performed to identify genes upregulated in mature IC. The expression data were validated by RT‐qPCR analysis performed in vitro and in planta , proteomic analysis of the IC secretome and biochemical assays. 1231 upregulated genes and 79 up‐accumulated proteins were identified. The data support the secretion of effectors by IC: phytotoxins, ROS, proteases, cutinases, plant cell wall–degrading enzymes and plant cell death–inducing proteins. Parallel upregulation of sugar transport and sugar catabolism–encoding genes would indicate a role of IC in nutrition. The data also reveal a substantial remodelling of the IC cell wall and suggest a role for melanin and chitosan in IC function. Lastly, mutagenesis of two upregulated genes in IC identified secreted fasciclin‐like proteins as actors in the pathogenesis of B . cinerea . These results support the role of IC in plant penetration and also introduce other unexpected functions for this fungal organ, in colonization, necrotrophy and nutrition of the pathogen.