Research Of Bacillus Subitilis B006Lipopeptides Antibiotics Against Fusarium Oxysporum F. Sp. Cucumerium

In this study, we used Bacillus subtilis B006as the reserch material, with the problem of fusarium wilt which caused by Fusarium oxysporum f. sp. cucumerinum (Foc) after continuous cropping, through detecting the B. subtilis B006lipopeptides and the population of strain B006and Foc in the cucumber rhizosphere, discussed the relation among lipopeptides, the population of strain B006and Foc, and the disease index. This study suggested its possible role in biological control of soilborne plant disease in vivo.This study shows that methanol extract from cell-free supernatants of Bacillus subtilis B006suppressed hyphal growth of Fusarium oxysporunm f. sp. cucumerinum more greatly than that of Phytophthora capsici, while suppressed spore germination of Foc less than that of zoospores of P. capsici. HPLC-ESI-MS analysis showed that the extract contained surfactin and fengycin with m/z at995,1009,1023,1037,1051and1436,1450,1478,1492. When cucumber was planted in sterile nursery substrate inoculated with B006at106cfu·g-1,surfactin and fengycin could also be detected with HPLC-ESI-MS from SPE-extracted lipopeptides of roots of the plants at4to6leaf stage, while not from that of uninoculated plant roots.A fast and accurate method was established to detect Bacillus subtilis B006and strain KW2-1in the soil by RT-PCR, the detection limit of B. subtilis B006was7.80E+01cfu·g-1and KW2-1was2ng·g-1Experiments in the greenhouse showed that:There were no significant influence with germination and plant height when cucumbers was planted in nursery substrate inoculated with B. subtilis B006; When cucumbers was planted in nursery substrate inoculated with B. subtilis B006and a second application when they were transplantation could reduce the population of fusarium oxysporium and the disease index; Used the B. subtilis B006twice after transplantation could effective controlthe cucumber fusarium wilt with using organic fertilizer, the population of B. subtilis B006was higher than the control1order of magnitude, the population of strain KW2-1was lower than the control; And it also could delay the disease two weeks and the disease effect was58.5%at5weeks after transplantation. Hole patterns organic fertilizer was no significant influence with the cucumber fusarium wilt and superiority of control efficiency. Detected with HPLC-ESI-MS from lipopeptides of roots, results:There was no relativity between the population of strain KW2-1and the kinds and contents of lipopeptides in the cucumber rhizosphere; while the treatment of using organic fertilizer, and the content of surfactin was higher than other treatments。...