Induction of Disease-resisting Enzymesin Sugarcane by Biocontrol Bacterium, TB2

Activities of polyphenol oxidase (PPO), peroxidase (POD), superoxide dismutase (SOD), phenylalanine ammonia lyase (PAL), and catalase (CAT) in sugarcane leaves were determined to evaluate the efficiency of a biocontrol bacterium, TB2, in inducing these disease-resisting enzymes, as well as the correlation between the enzymes and the disease resistance of sugarcane toward red rot pathogens. Treatments, including pathogen inoculation,TB2 spraying, and TB2 sprayings before and after pathogen inoculation, were applied to examine the variations on the enzymatic activities in the leaves of the treated sugarcane plants.It was found that the enzymatic activities in the treated plants were significantly higher than those in control, indicating an induction effect byeither TB2 or the red rot pathogens. The effect was greater when TB2 was applied along with the pathogenic inoculation, especiallyif the leaves were pre-sprayed with TB2.Although the biocontrol bacterium showed a stronger induction ability than the pathogens, a synergism seemed evidentwhen both were present on sugarcane.