title: Interaction of barley powdery mildew effector candidate CSEP0055 with the defence protein PR17c.
abstract: A large number of effector candidates have been identified recently in powdery mildew fungi. However, their roles and how they perform their functions remain unresolved. In this study, we made use of host-induced gene silencing and confirmed that the secreted barley powdery mildew effector candidate, CSEP0055, contributes to the aggressiveness of the fungus. This result suggests that CSEP0055 is involved in the suppression of plant defence. A yeast two-hybrid screen indicated that CSEP0055 interacts with members of the barley pathogenesis-related protein families, PR1 and PR17. Interaction with PR17c was confirmed by bimolecular fluorescence complementation analyses. Down-regulation and over-expression of PR17c in epidermal cells of barley confirmed that this protein is important for penetration resistance against the powdery mildew fungus. In line with this, PR17c was found to be apoplastic, localizing to the papillae formed in response to this fungus. The CSEP0055 transcript did not start to accumulate until 24 h after inoculation. This suggests that this gene is expressed too late to influence primary penetration events, but rather sustains the fungus at sites of secondary penetration, where PR17c appears to be able to accumulate.
authors.affiliation: Department of Agriculture and Ecology, University of Copenhagen, 1871 Frederiksberg, Denmark.
authors.forename: Wen-Jing
authors.initials: WJ
authors.lastname: Zhang
authors.forename: Carsten
authors.initials: C
authors.lastname: Pedersen
authors.forename: Mark
authors.initials: M
authors.lastname: Kwaaitaal
authors.forename: Per L
authors.initials: PL
authors.lastname: Gregersen
authors.forename: Sara M
authors.initials: SM
authors.lastname: Mørch
authors.forename: Susanne
authors.initials: S
authors.lastname: Hanisch
authors.forename: Astrid
authors.initials: A
authors.lastname: Kristensen
authors.forename: Anja T
authors.initials: AT
authors.lastname: Fuglsang
authors.forename: David B
authors.initials: DB
authors.lastname: Collinge
authors.forename: Hans
authors.initials: H
authors.lastname: Thordal-Christensen
mesh_terms: D001203:Ascomycota / Q000502:physiology*; D005453:Fluorescence; D005656:Fungal Proteins / Q000378:metabolism*; D020868:Gene Silencing; D001467:Hordeum / Q000166:cytology / Q000378:metabolism / Q000382:microbiology*; D054884:Host-Pathogen Interactions; D010935:Plant Diseases / Q000382:microbiology*; D010940:Plant Proteins / Q000378:metabolism*; D021381:Protein Transport; D020798:Two-Hybrid System Techniques
chemical_list: D005656:Fungal Proteins; D010940:Plant Proteins