Rapid identification of Hyaloperonospora arabidopsidis RXLR effectors with virulence function in Arabidopsis using mixed bacterial infections

BADEL J.L; GREENSHIELDS D; FABRO G; PIQUEREZ S; ISHAQUE N; JONES J.D.G.

Toulouse, France

Congreso; Oomycete Molecular Genetics Network Toulouse 2010; 2010

Oomycete Molecular Genetics Network

The interaction between Hyaloperonospora arabidopsidis (Hpa) and Arabidopsis is a well

established model system to study oomycete pathogenesis and plant defence response against

obligate biotrophic parasites. Hpa has been divided into several races depending on the

outcome of its interaction with different Arabidopsis genotypes. Hpa Emoy2, for instance,

causes disease in Wei-0 and Oy-0, but not in Col-0, Ler-0, Nd-0, and Ws-0, due to the

specific recognition conferred by RPP (recognition to Peronospora parasitica, former Hpa

name) resistance genes. It is estimated that during infection Emoy2 delivers into plant cells

more than a hundred effector proteins that work in concert to cause disease. A group of these

effectors is characterized by the presence of an RXLR motif, which has been shown to be

required for translocation of Phytophthora effectors into the plant cytoplasm (Duo et al.,

2008; Whisson, S.C., et al. 2007). Using the Effector Detector system (Sohn et al. 2007) for

heterologous expression and mixed Pseudomonas syringae pv. tomato DC3000 (Pst

DC3000) infections we have been able to identify RXLR effector candidates that have

virulence function during the interaction of Emoy2 with different Arabidopsis genotypes

based on the competitive advantage of the bacterial strain carrying the plasmid-borne effector

candidate.