Abstract:
To evaluate the effects of foliar spraying of two inducers (mineral elemental silicon, Si; plant elicitor benzothiadiazole, BTH) on tobacco bacterial wilt, the content of tobacco bacteria wilt pathogen in tobacco roots, the Si contents in tobacco roots, stalks and leaves, the activity of defense enzymes and the expressions of resistance genes in tobacco leaves and the incidence of tobacco bacteria wilt in laboratory and fields were analyzed after Si and BTH treatments. The results showed that the content of tobacco bacteria wilt pathogen in roots was significantly reduced by Si and BTH, and the Si content in the roots was significantly increased by the Si treatment. The activities of defense enzymes in leaves were also enhanced by the Si and BTH treatments, in which the activities of peroxidase (POD) and
β-1, 3-glucanase (GLU) were significantly promoted by the Si treatment, as did those of GLU, polyphenol oxidase (PPO) and phenylalanine ammonialyase (PAL) by BTH. The expressions of resistance genes (
EFE26,
ACC Oxidase,
HIN1 and
PR2) in tobacco were significantly increased by both procedures, the expressions of
PR1,
PR1a/
c,
EFE26,
ACC Oxidase and
HIN1 were significantly higher in tobacco treated with BTH; while the expression of
PR2 was significantly higher in tobacco treated with the Si treatment. Si induced the resistance to tobacco bacterial wilt through enhancing the Si accumulation in tobacco roots, as did BTH through promoting the expressions of resistance-related genes. In summary, this study demonstrated that foliar application of Si and BTH induced the resistance to tobacco bacterial wilt in tobacco in two different mechanisms.