New papers from Vlot and Schwab labs.
Folic acid induces salicylic acid-dependent immunity in Arabidopsis and enhances susceptibility to Alternaria brassicicola.
Fini Wittek, Basem Kanawati, Marion Wenig, Thomas Hoffmann Katrin Franz-Oberdorf, Wilfried Schwab, Philippe Schmitt-Kopplin and A. Corina Vlot (2014).
Folates are essential for one-carbon transfer reactions in all organisms and contribute for example to de novo DNA synthesis. Here, we detected the folate precursors 7,8-dihydropteroate (DHP) and 4-amino-4-deoxychorismate (ADC) in extracts from Arabidopsis thaliana plants by Fourier transform ion cyclotron resonance mass spectrometry. The accumulation of DHP but not ADC was induced after infection of plants with Pseudomonas syringae delivering the effector protein AvrRpm1. Application of folic acid or the DHP precursor 7,8-dihydroneopterin enhanced resistance in Arabidopsis to P. syringae and elevated the transcript accumulation of the salicylic acid (SA) marker gene PATHOGENESIS-RELATED1 both in the treated and systemic untreated leaves. DHN- and folic acid-induced systemic resistance was dependent on SA biosynthesis and signaling. Similarly to SA, folic acid application locally enhanced Arabidopsis susceptibility to the necrotrophic fungus Alternaria brassicicola. Together, the data associate the folic acid pathway with innate immunity in Arabidopsis, simultaneously activating local and systemic SA-dependent resistance to P. syringae and suppressing local resistance to A. brassicicola.
