A new ice-nucleating bacterium, KUEN-3, was isolated from strawberry leaves. The ice-nucleating bacterium was found in the pale yellow colony group. Strain KUEN-3 was identified as Erwinia uredovora from its taxonomical characteristics. Whenstrain KUEN-3was cultured aerobically in a mediumconsisting of Simmons-citric acid broth (pH 6.1) for 24 hr at 18°C, the ice-nucleating activity of strain KUIN-3cells was obtained. The ice-nucleating temperature, J50 (°C) was detected at-2.8°C in cell suspensions (1.1 x 108cells/ml) of strain KUEN-3.The ice-nucleating temperature was significantly decreased by treating cell suspensions for 30min at 40°C and was completely lost by heating them at 90°C. The plot of ice-nucleating temperature versus treatment temperature (°C) is similar to the curve that was obtained for cell suspensions of another ice-nucleating bacteria. The susceptibility of cell ice nuclei to urea or protein-modifying reagents suggests that proteins participate in the ice-nucleating event.

No abstract