Phytoparasitica, cilt.31, sa.4, ss.381-392, 2003 (SCI-Expanded)
Intercellular washing fluid (IWF) obtained from the susceptible Arabidopsis accession Ws-eds1 inoculated with Peronospora parasitica isolate Emoy-2, contained an elicitor of necrosis with ecotype specificity towards Arabidopsis accessions with particular resistance genes. This elicitor caused necrosis on the highly resistant accessions La-er, Nd-l and partly on Col-5, but not on the susceptible accessions Ws-eds1 and Oy-0. In resistant plants, injection of IWF caused hypersensitive reaction (HR)-like cell collapse which was associated with the accumulation of phenolics and lignin-like material in walls of cells undergoing cell death. The elicitor is sensitive to proteinase K and pronase enzymes, heating and autoclaving but insensitive to periodate oxidation, freezing and thawing, and is not dialyzable. Results suggest that the elicitor is a protein. Fractionation experiments using size-exclusion membranes revealed that elicitor activity has a molecular weight in excess of 100 kDa.