Induction of systemic resistance by Bacillus subtilis isolate Bst against Rotylenchulus reniformis in tomato
AbstractA rhizobacterium, Bacillus subtilis (isolate Bst) was tested for its ability to induce systemic resistance against RotylenchuIus rem/ormis in tomato. A split root system was used to keep the inducer (rhizobacterium) and the challenger (nematode) spatially separate and observations on nematode penetration, its multiplication and growth characters were recorded. The results show that the nematode penetration was reduced by 44.5% in the split root in which one half received a bacterial cell suspension (10^10 cells/mIl as a soil drench and a week after the other half was inoculated with the nematode. All growth characters measured were increased to some extent by the bacterium, but only fresh shoot length and fresh shoot weight significantly differed from the control. The nematode multiplication rate was reduced significantly when the bacterial soil drench was applied a week before nematode inoculation but not in those treatments that received simultaneous inoculations of the bacterium and the nematode. The results indicate that BSt could induce systemic resistance in tomato against R. reniformis.