title: Effector genomics accelerates discovery and functional profiling of potato disease resistance and phytophthora infestans avirulence genes.
abstract: Potato is the world's fourth largest food crop yet it continues to endure late blight, a devastating disease caused by the Irish famine pathogen Phytophthora infestans. Breeding broad-spectrum disease resistance (R) genes into potato (Solanum tuberosum) is the best strategy for genetically managing late blight but current approaches are slow and inefficient. We used a repertoire of effector genes predicted computationally from the P. infestans genome to accelerate the identification, functional characterization, and cloning of potentially broad-spectrum R genes. An initial set of 54 effectors containing a signal peptide and a RXLR motif was profiled for activation of innate immunity (avirulence or Avr activity) on wild Solanum species and tentative Avr candidates were identified. The RXLR effector family IpiO induced hypersensitive responses (HR) in S. stoloniferum, S. papita and the more distantly related S. bulbocastanum, the source of the R gene Rpi-blb1. Genetic studies with S. stoloniferum showed cosegregation of resistance to P. infestans and response to IpiO. Transient co-expression of IpiO with Rpi-blb1 in a heterologous Nicotiana benthamiana system identified IpiO as Avr-blb1. A candidate gene approach led to the rapid cloning of S. stoloniferum Rpi-sto1 and S. papita Rpi-pta1, which are functionally equivalent to Rpi-blb1. Our findings indicate that effector genomics enables discovery and functional profiling of late blight R genes and Avr genes at an unprecedented rate and promises to accelerate the engineering of late blight resistant potato varieties.
authors.affiliation: Wageningen UR Plant Breeding, Wageningen, The Netherlands. Vivianne.Vleeshouwers@wur.nl
authors.forename: Vivianne G A A
authors.initials: VG
authors.lastname: Vleeshouwers
authors.forename: Hendrik
authors.initials: H
authors.lastname: Rietman
authors.forename: Pavel
authors.initials: P
authors.lastname: Krenek
authors.forename: Nicolas
authors.initials: N
authors.lastname: Champouret
authors.forename: Carolyn
authors.initials: C
authors.lastname: Young
authors.forename: Sang-Keun
authors.initials: SK
authors.lastname: Oh
authors.forename: Miqia
authors.initials: M
authors.lastname: Wang
authors.forename: Klaas
authors.initials: K
authors.lastname: Bouwmeester
authors.forename: Ben
authors.initials: B
authors.lastname: Vosman
authors.forename: Richard G F
authors.initials: RG
authors.lastname: Visser
authors.forename: Evert
authors.initials: E
authors.lastname: Jacobsen
authors.forename: Francine
authors.initials: F
authors.lastname: Govers
authors.forename: Sophien
authors.initials: S
authors.lastname: Kamoun
authors.forename: Edwin A G
authors.initials: EA
authors.lastname: Van der Vossen
mesh_terms: D003001:Cloning, Molecular; D005656:Fungal Proteins / Q000235:genetics; D020869:Gene Expression Profiling; D023281:Genomics; D007113:Immunity, Innate; D010838:Phytophthora / Q000235:genetics / Q000472:pathogenicity*; D010935:Plant Diseases / Q000235:genetics*; D011198:Solanum tuberosum / Q000235:genetics*; D014774:Virulence / Q000235:genetics
chemical_list: D005656:Fungal Proteins; C112546:IpiO1 protein, Phytophthora infestans