title: Conserved C-terminal motifs required for avirulence and suppression of cell death by Phytophthora sojae effector Avr1b.
abstract: The sequenced genomes of oomycete plant pathogens contain large superfamilies of effector proteins containing the protein translocation motif RXLR-dEER. However, the contributions of these effectors to pathogenicity remain poorly understood. Here, we show that the Phytophthora sojae effector protein Avr1b can contribute positively to virulence and can suppress programmed cell death (PCD) triggered by the mouse BAX protein in yeast, soybean (Glycine max), and Nicotiana benthamiana cells. We identify three conserved motifs (K, W, and Y) in the C terminus of the Avr1b protein and show that mutations in the conserved residues of the W and Y motifs reduce or abolish the ability of Avr1b to suppress PCD and also abolish the avirulence interaction of Avr1b with the Rps1b resistance gene in soybean. W and Y motifs are present in at least half of the identified oomycete RXLR-dEER effector candidates, and we show that three of these candidates also suppress PCD in soybean. Together, these results indicate that the W and Y motifs are critical for the interaction of Avr1b with host plant target proteins and support the hypothesis that these motifs are critical for the functions of the very large number of predicted oomycete effectors that contain them.
authors.affiliation: Virginia Bioinformatics Institute, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061, USA.
authors.forename: Daolong
authors.initials: D
authors.lastname: Dou
authors.forename: Shiv D
authors.initials: SD
authors.lastname: Kale
authors.forename: Xinle
authors.initials: X
authors.lastname: Wang
authors.forename: Yubo
authors.initials: Y
authors.lastname: Chen
authors.forename: Qunqing
authors.initials: Q
authors.lastname: Wang
authors.forename: Xia
authors.initials: X
authors.lastname: Wang
authors.forename: Rays H Y
authors.initials: RH
authors.lastname: Jiang
authors.forename: Felipe D
authors.initials: FD
authors.lastname: Arredondo
authors.forename: Ryan G
authors.initials: RG
authors.lastname: Anderson
authors.forename: Poulami B
authors.initials: PB
authors.lastname: Thakur
authors.forename: John M
authors.initials: JM
authors.lastname: McDowell
authors.forename: Yuanchao
authors.initials: Y
authors.lastname: Wang
authors.forename: Brett M
authors.initials: BM
authors.lastname: Tyler
mesh_terms: D020418:Algal Proteins / Q000737:chemistry / Q000502:physiology*; D000595:Amino Acid Sequence; D000818:Animals; D016923:Cell Death / Q000502:physiology*; D051379:Mice; D008969:Molecular Sequence Data; D010838:Phytophthora / Q000472:pathogenicity*; D017386:Sequence Homology, Amino Acid; D014774:Virulence / Q000502:physiology*
chemical_list: D020418:Algal Proteins