Phytophthora infestans RXLR Effector AVR1 Interacts with Exocyst Component Sec5 to Manipulate Plant Immunity.
Phytophthora infestans secretes numerous RXLR effectors that modulate host defense and thereby pave the way for successful invasion. Here, we show that the RXLR effector AVR1 is a virulence factor that promotes colonization and suppresses callose deposition, a hallmark of basal defense. To identify host targets of AVR1, we performed yeast two-hybrid screens and selected Sec5 as a candidate. Sec5 is a subunit of the exocyst, a protein complex that is involved in vesicle trafficking. AVR1-like (A-L), a close homolog of AVR1, also acts as a virulence factor, but unlike AVR1, A-L does not suppress CRINKLER2 (CRN2)-induced cell death or interact with Sec5. Compared with AVR1, A-L is shorter and lacks the carboxyl-terminal tail, the T-region that is crucial for CRN2-induced cell death suppression and Sec5 interaction. In planta analyses revealed that AVR1 and Sec5 are in close proximity, and coimmunoprecipitation confirmed the interaction. Sec5 is required for secretion of the pathogenesis-related protein PR-1 and callose deposition and also plays a role in CRN2-induced cell death. Our findings show that P. infestans manipulates an exocyst subunit and thereby potentially disturbs vesicle trafficking, a cellular process that is important for basal defense. This is a novel strategy that oomycete pathogens exploit to modulate host defense.
Laboratory of Phytopathology, Wageningen University, 6708 PB, Wageningen, The Netherlands (Y.D., M.H.M., K.B., F.G.);Division of Plant Sciences, College of Life Science, University of Dundee at the James Hutton Institute, Invergowrie, Dundee, United Kingdom (P.R.J.B.); andPlant-Microbe Interactions, Department of Biology, Faculty of Science, Utrecht University, 3584 CH, Utrecht, The Netherlands (K.B.).
Yu
http://orcid.org/0000-0002-3512-0200
Y
Du
Laboratory of Phytopathology, Wageningen University, 6708 PB, Wageningen, The Netherlands (Y.D., M.H.M., K.B., F.G.);Division of Plant Sciences, College of Life Science, University of Dundee at the James Hutton Institute, Invergowrie, Dundee, United Kingdom (P.R.J.B.); andPlant-Microbe Interactions, Department of Biology, Faculty of Science, Utrecht University, 3584 CH, Utrecht, The Netherlands (K.B.).
Mohamed H
MH
Mpina
Laboratory of Phytopathology, Wageningen University, 6708 PB, Wageningen, The Netherlands (Y.D., M.H.M., K.B., F.G.);Division of Plant Sciences, College of Life Science, University of Dundee at the James Hutton Institute, Invergowrie, Dundee, United Kingdom (P.R.J.B.); andPlant-Microbe Interactions, Department of Biology, Faculty of Science, Utrecht University, 3584 CH, Utrecht, The Netherlands (K.B.).
Paul R J
http://orcid.org/0000-0002-6559-3746
PR
Birch
Laboratory of Phytopathology, Wageningen University, 6708 PB, Wageningen, The Netherlands (Y.D., M.H.M., K.B., F.G.);Division of Plant Sciences, College of Life Science, University of Dundee at the James Hutton Institute, Invergowrie, Dundee, United Kingdom (P.R.J.B.); andPlant-Microbe Interactions, Department of Biology, Faculty of Science, Utrecht University, 3584 CH, Utrecht, The Netherlands (K.B.).
Klaas
http://orcid.org/0000-0002-8141-3880
K
Bouwmeester
Laboratory of Phytopathology, Wageningen University, 6708 PB, Wageningen, The Netherlands (Y.D., M.H.M., K.B., F.G.);Division of Plant Sciences, College of Life Science, University of Dundee at the James Hutton Institute, Invergowrie, Dundee, United Kingdom (P.R.J.B.); andPlant-Microbe Interactions, Department of Biology, Faculty of Science, Utrecht University, 3584 CH, Utrecht, The Netherlands (K.B.) francine.govers@wur.nl.
Francine
http://orcid.org/0000-0001-5311-929X
F
Govers
D016923:Cell Death; D005936:Glucans / Q000378:metabolism; D054884:Host-Pathogen Interactions; D055750:Phytophthora infestans / Q000276:immunology* / Q000378:metabolism / Q000472:pathogenicity; D010935:Plant Diseases / Q000276:immunology* / Q000469:parasitology; D057865:Plant Immunity; D018515:Plant Leaves / Q000276:immunology / Q000469:parasitology; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D021381:Protein Transport; D014026:Nicotiana / Q000276:immunology / Q000469:parasitology*; D020798:Two-Hybrid System Techniques; D037521:Virulence Factors / Q000235:genetics / Q000378:metabolism*
D005936:Glucans; D010940:Plant Proteins; D037521:Virulence Factors; C048306:callose