Antibacterial activity of Lansiumamide B to tobacco bacterial wilt (Ralstonia solanacearum).

Tobacco bacterial wilt caused by Ralstonia solanacearum is one of the most serious diseases of tobacco in the area of tobacco cultivation. As there is no effective control method for tobacco bacterial wilt diseases, developing new antibacterial agents in tobacco will make great practical sense. The antibacterial activity against R. solanacearum of Lansiumamide B which is isolated from the seeds of Clausena lansium is reported in this paper for the first time. The bioassay results indicate that Lansiumamide B could completely inhibit the growth of R. solanacearum at the concentration of 125 mg/L in vitro, the EC50 and EC90 are 48.82 mg/L and 86.26 mg/L, respectively. The result of pot experiments indicates that the control efficiency of the Lansiumamide B on tobacco bacterial wilt are 95.84%, 91.67% and 86.38% at 7 days, 14 days and 21 days after treatment at the concentration of 100mg/kg, respectively, nearly 40 times higher than Streptomycin, a special fungicide to the disease, at 21 days after treatment with root irrigation method. These results suggest that Lansiumamide B has the potential of developing as a new type of plant-type fungicide on controlling the diseases of tobacco bacterial wilt.