枯草芽孢杆菌G3菌株的抗菌物质及其特性

Antif ungal substances of Bacillus subtilis strain G3 and their properties

产几丁质酶枯草芽孢杆菌G3菌株的固体培养物在黄瓜灰霉病菌和番茄叶霉病菌抑菌试验中证实,抑菌活性物质存在于过滤上清液中,它们是从酸沉淀物中提取出的伊枯草菌素、生物表面活性素和存在于盐析粗蛋白中的几丁质酶。在叶霉孢子萌发试验中,伊枯草菌素微弱地抑制孢子萌发但强烈破坏芽管和新生菌丝;生物表面活性素和几丁质酶则强烈抑制孢子萌发并长久性地抑制芽管伸长。在PDA平板上的灰霉菌丝抑菌试验中,伊枯草菌素抑制菌丝生长,引发菌丝顶端膨大,形成泡囊,泡囊破裂后原生质外泄;几丁质酶抑制菌丝生长,引发产生不规则的菌丝团;生物表面活性素在平皿上对菌丝则不显示出抑菌活性。

Bacillus subtilis strain G3, a chitinase-produing biocontrol agent, showed a strong activity to inhibit the growth of pathogenic fungi Botrytis cinerea and Cladosporium fulvum. The antifungal substances were prepared from the solid culture filtrate. They were iturin and surfactin extracted from acid precipitate and the chitinase obtained in crude proteins by ammonium sulfate precipitation. Iturin showed a relatively weak activity to inhibit spore germination of C. fulvum, but a strong activity to break the germ-tube and new hyphae. Surfactin and chitinase were inhibitory to spore germination and suppressive to germ-tube elongation. In the antibiosis detection with B. cinerea on plate,iturin inhibited mycelial growth and caused the vesicle structures in the tips of hyphae,then the cell wall broken and the protoplasm leaked out. Chitinase also inhibited mycelial growth and caused the hyphae abnormal. Surfactin showed no antifungal activity to B. cinerea.