A secreted metal-binding protein protects necrotrophic phytopathogens from reactive oxygen species

Lulu Liu (1) , Virginie Gueguen-Chaignon (2, 3) , Isabelle R. Gonçalves (4) , Christine C. Rascle (4) , Martine Rigault (5) , Alia Dellagi (5) , Elise Loisel (4) , Nathalie Poussereau (4) , Agnès Rodrigue (1) , Laurent Terradot (3) , Guy Condemine (1)

1 MTSB - Trafic et signalisation membranaires chez les bactéries
2 SFR Biosciences
3 MMSB - Microbiologie moléculaire et biochimie structurale / Molecular Microbiology and Structural Biochemistry
4 GFCP - Génomique fonctionnelle des Champignons Phytopathogènes
5 IJPB - Institut Jean-Pierre Bourgin

Few secreted proteins involved in plant infection common to necrotrophic bacteria, fungi and oomycetes have been identified except for plant cell wall-degrading enzymes. Here we study a family of iron-binding proteins that is present in Gram-negative and Gram-positive bacteria, fungi, oomycetes and some animals. Homolog proteins in the phytopathogenic bacterium Dickeya dadantii (IbpS) and the fungal necrotroph Botrytis cinerea (BcIbp) are involved in plant infection. IbpS is secreted, can bind iron and copper, and protects the bacteria against H 2 O 2-induced death. Its 1.7 Å crystal structure reveals a classical Venus Fly trap fold that forms dimers in solution and in the crystal. We propose that secreted Ibp proteins binds exogenous metals and thus limit intracellular metal accumulation and ROS formation in the microorganisms.

Domaines: Biologie moléculaire; Biochimie [q-bio.BM]; Génomique, Transcriptomique et Protéomique [q-bio.GN]; Bactériologie

Lulu Liu, Virginie Gueguen-Chaignon, Isabelle R. Gonçalves, Christine C. Rascle, Martine Rigault, et al.. A secreted metal-binding protein protects necrotrophic phytopathogens from reactive oxygen species. Nature Communications, 2019, 10 (1), pp.4853. ⟨10.1038/s41467-019-12826-x⟩. ⟨hal-02336631⟩