LC-MS analysis of oligogalacturonide production from leaves of A. thaliana plants (cultivated at high (HN) or low N (LN)) incubated for 18 h in liquid medium supplemented with spores of the WT, BcPNL1 mutant (pnl15, pnl16 and pnl17) and complemented strains (pnlC1 and pnlC2) of B. cinerea.