title: Trafficking arms: oomycete effectors enter host plant cells.
abstract: Oomycetes cause devastating plant diseases of global importance, yet little is known about the molecular basis of their pathogenicity. Recently, the first oomycete effector genes with cultivar-specific avirulence (AVR) functions were identified. Evidence of diversifying selection in these genes and their cognate plant host resistance genes suggests a molecular "arms race" as plants and oomycetes attempt to achieve and evade detection, respectively. AVR proteins from Hyaloperonospora parasitica and Phytophthora infestans are detected in the plant host cytoplasm, consistent with the hypothesis that oomycetes, as is the case with bacteria and fungi, actively deliver effectors inside host cells. The RXLR amino acid motif, which is present in these AVR proteins and other secreted oomycete proteins, is similar to a host-cell-targeting signal in virulence proteins of malaria parasites (Plasmodium species), suggesting a conserved role in pathogenicity.
authors.affiliation: Scottish Crop Research Institute, Invergowrie, Dundee DD2 5DA, Scotland, UK. pbirch@scri.sari.ac.uk
authors.forename: Paul R J
authors.initials: PR
authors.lastname: Birch
authors.forename: Anne P
authors.initials: AP
authors.lastname: Rehmany
authors.forename: Leighton
authors.initials: L
authors.lastname: Pritchard
authors.forename: Sophien
authors.initials: S
authors.lastname: Kamoun
authors.forename: Jim L
authors.initials: JL
authors.lastname: Beynon
mesh_terms: D020418:Algal Proteins / Q000235:genetics / Q000378:metabolism; D020816:Amino Acid Motifs; D017360:Arabidopsis; D009868:Oomycetes / Q000235:genetics / Q000378:metabolism / Q000472:pathogenicity*; D010935:Plant Diseases / Q000382:microbiology*; D010940:Plant Proteins / Q000378:metabolism; D011198:Solanum tuberosum
chemical_list: D020418:Algal Proteins; D010940:Plant Proteins