油菜内生拮抗细菌SF4对油菜菌核病菌的抑制作用研究

从油菜幼苗中分离出110个内生细菌。采用平板对峙法进行筛选，有4株菌对核盘菌有不同程度的抑制作用。经连续传代10次后，菌株SF4仍具有较高的生防活性。该菌株对核盘菌的菌丝生长发育有显著的抑制效果。在显微镜的观察下，被抑制的菌丝发生畸形，内含物分布不均匀。菌株SF4的挥发性产物及无菌发酵液都能抑制核盘菌的菌丝生长。挥发性产物对菌丝的最高抑制率为33.13%。无菌发酵液的抑制效果随培养时间的不同而有显著差异，96 h的无菌发酵液抑制效果最好。菌株SF4的无菌发酵液可推迟核盘菌菌核形成的时间，减少菌核数目，也可推迟菌核的萌发。在油菜叶片离体实验中，该菌株的菌悬液及无菌发酵液对发病有明显的抑制作用。

Inhibitory effects of antagonistic endophytic bacterium SF4 in oilseed rape against Sclerotinia sclerotiorum

One hundred and ten endophytic bacterial strains were isolated from oilseed rape seedlings. In the dual-culture test in plates, there are 4 strains exhibited antifungal activities against S. sclerotiorum. Subcultured 10 times, strains SF4 showed significant biocontrol effect. Strain SF4 inhibited the growth of mycelia and induced alterations on mycelium morphology of S. sclerotiorum, such as mycelium inclusions uneven distributed and deformation. The volatile products and cell-free fermentation broth of SF4 could both inhibit the growth of mycelia. The volatile products from SF4 could evidently inhibit mycelium growth of S. sclerotiorum, with the inhibitory rate of 33.13%. The biocontrol efficacy of fermentation broth was different with the different culture time, and the inhibition effect at 96 h treatment was 34.33%. In addition, strain SF4 could put off sclerotia generation, reduce the number of sclerotia and postpone the sclerotia germination. Leaves experiments in vitro demonstrated that the bacterial of SF4 could significantly inhibit the outburst of S. sclerotiorum.