Poster De Conférence Année : 2022

Functional characterization of a Botrytis cinerea protease involved in the infection process.

Résumé

Botrytis cinerea is a nectrotrophic plant pathogen that leads to important economic losses in many crops. This fungus has a large arsenal of virulence factors such as cell wall degrading enzymes, toxins, reactive oxygen species production, small RNA production and proteases. Furthermore, B. cinerea is known to acidify the medium by secreting succinic and citric acids as well as oxalate to enhance enzymatic activities during the infection process. Recently, a new class of proteases that work at a very low pH has been discovered. These glutamic proteases, almost entirely restricted to filamentous fungi, comprise 3 homologs in B. cinerea. Roland et al showed that BcACP1 encodes a glutamic protease that is regulated in vitro by nitrogen and sulfur availability and pH (2009, Microbiology, 155(6), 2097-2105). Other works point out the facts that this protease is present in the early secretome of botrytis and preferentially produced from infection cushions, known for their role in plant-cell wall penetration. Our team demonstrated that the expression of the BcACP1 gene is up-regulated on infected plants grown with high nitrate supply, which are more susceptible to the pathogen in comparison with low nitrate supply (Soulie et al. 2020, Molecular Plant Pathology, 21, 1436– 1450). This induction cannot be explained by nutrient availability, indicating a fine regulation of this effector by the plant physiological state. As the protease is expected to localize in the apoplastic space during the early stage of the interaction, we are searching for specific targets and regulators in this compartment using proteomic and metabolomic analysis on apoplast washing fluid (AWF) extracts. On the other hand, we are analyzing the ability of BcACP1, purified in E. coli, to degrade plant apoplastic proteins and to activate or repress plant defense reactions on different host species. Functional analysis reveals that neither BcACP2 nor BcACP3 are indispensable for pathogenicity and development. Since BcACP2 transcription is up-regulated in the ΔBcacp1 mutant, analysis of the double mutants is under process and might reveal new clues about the role of this protease family. Furthermore, this work will lead us to the description of the infected AWF proteome and metabolome at the beginning of the infectious process. This analysis might enable us to identify novel plant compounds and effectors involved in apoplastic immunity as well as early secreted effectors of the fungus.

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Dates et versions

hal-05281637 , version 1 (24-09-2025)

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  • HAL Id : hal-05281637 , version 1

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Antoine Davière, Marie-Christine M.-C. Soulie, Mathilde Fagard. Functional characterization of a Botrytis cinerea protease involved in the infection process.. Congrès Botrysclero 2022, Jun 2022, Avignon, France. ⟨hal-05281637⟩
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