Measurement of β-1,3 Glucanase Activity in Permeabilized Discs of Leaves of Healthy and Scald-Diseased Plants

Leaf discs of five cultivars of sugarcane exhibiting different degree of susceptibility to leaf scald were used to measure β-1,3 glucanase activity before and after experimental infection with Xanthomonas albilineans. Leaf discs were permeabilized with iso-propanol to facilitate the uptake of the enzyme substrate by intact tissues and to improve the enzyme assay. Bacterial infection significantly enhances β-1,3 glucanase activity of sensitive cultivars whereas significantly decreased that of the resistant one. Low concentrations of salicylate increase the hydrolase activity whereas jasmonic acid do not act as an elicitor of the enzyme and β-1,3 glucanase, such as laminarin, significantly inhibits the production of β-1,3 glucanase. Thus, the enzyme must be considered as a sensitivity factor induced by the pathogen.