|Publication Type:||Journal Article|
|Year of Publication:||2013|
|Authors:||Kopischke, M, Westphal, L, Schneeberger, K, Clark, R, Ossowski, S, Wewer, V, Fuchs, R, Landtag, J, Hause, G, Dörmann, P, Lipka, V, Weigel, D, Schulze-Lefert, P, Scheel, D, Rosahl, S|
|Journal:||The Plant Journal|
|Keywords:||Arabidopsis, callose, mesophyll, non-host resistance, Phytophthora infestans, sterol ester|
Non-host resistance of Arabidopsis thaliana against Phytophthora infestans, the causal agent of late blight disease of potato, depends on efficient extracellular pre- and post-invasive resistance responses. Pre-invasive resistance against P. infestans requires the myrosinase PEN2. To identify additional genes involved in non-host resistance to P. infestans, a genetic screen was performed by re-mutagenesis of pen2 plants. Fourteen independent mutants were isolated that displayed an enhanced response to Phytophthora (erp) phenotype. Upon inoculation with P. infestans, two mutants, pen2-1 erp1-3 and pen2-1 erp1-4, showed an enhanced rate of mesophyll cell death and produced excessive callose deposits in the mesophyll cell layer. ERP1 encodes a phospholipid:sterol acyltransferase (PSAT1) that catalyzes the formation of sterol esters. Consistent with this, the tested T-DNA insertion lines of PSAT1 are phenocopies of erp1 plants. Sterol ester levels are highly reduced in all erp1/psat1 mutants, whereas sterol glycoside levels are increased twofold. Excessive callose deposition occurred independently of PMR4/GSL5 activity, a known pathogen-inducible callose synthase. A similar formation of aberrant callose deposits was triggered by the inoculation of erp1 psat1 plants with powdery mildew. These results suggest a role for sterol conjugates in cell non-autonomous defense responses against invasive filamentous pathogens.
|Short Title:||The Plant Journal|
Impaired sterol ester synthesis alters the response of Arabidopsis thaliana to Phytophthora infestans