Salicylic acid as a possible component in the susceptibility of apple rootstock for fire blight infections

Abstract

Concentrations of salicylic acid, known to be an important endogenous component in plant-pathogen interactions, were determined in apple rootstocks inoculated with Erwinia amylovora. Concentrations were measured over a period of 14 days, in four different leaves; the inoculated leaf, the first and the second leaf above, and the first leaf below the inoculated leaf. The concentration of salicylic acid increased significantly in the inoculated leaf from day 5 until day 11. The concentration in the mock-inoculated leaves did not increase significantly.