营养添加剂对枯草芽孢杆菌G3^(str)在土壤中繁殖及其抑菌物质分泌能力的影响

Influence of Nutritional Additives on Propagation and Production of Antifungal Substance of Bacillus subtilis G3^(str) in Soil

从生防菌G3菌株筛选到的抗链霉素自然突变株G3str,保持G3原有的抑菌活性,产伊枯草菌素和生物表面活性素,能抑制多种植物病原真菌。25℃下,营养添加剂对G3str菌在不灭菌土壤中前5d有一定的增殖作用;10d后G3str菌在土壤中主要以芽孢的形态存活;60d后,G3str菌在土壤中仍以106cfu/g水平存活。G3str菌在土壤中增殖时分泌少量的伊枯草菌素,但被快速分解;同时分泌较多的生物表面活性素,营养添加剂的加入明显促进其分泌。

Bacillus subtilis G3^str is a spontaneous streptomycin-resistant mutant of B. subtilis G3. G3^str as well as G3 produce iturin and surfactin, and suppress several plant pathogenic fungi. The visible increment in cell number of G3^str by addition of nutritional additives was observed in non-sterile soil at 25 ℃. The total cell number of G3^str in soil increased obviously during the first 5 days, then decreased and survived in form of spores in the soil after 10 days. Sixty days later, it also survived at a level of 106 cfu/g soil. B. subtilis G3^str excreted a little iturin, but degraded quickly, in non-sterile soil. Large amount of surfactin was also produced at the same time, and nutritional additives greatly increased the production.