绛红褐链霉菌YSSPG3的发酵条件及其发酵滤液对杂交竹梢枯病的防治作用

Fermentation of Streptomyces purpeofuscus YSSPG3 and the control effect of its culture filtrate on hybrid bamboo blight

绛红褐链霉菌YSSPG3是从四川碧峰峡撑×绿杂交竹健康植株根际分离到的一株对杂交竹梢枯病菌有抗菌活性的放线菌。为进一步明确该菌的生防潜力,采用正交设计进行发酵培养基优化,并通过分生孢子萌发试验、菌丝抑制试验、离体枝叶接种试验及田间防治试验,研究了优化发酵培养滤液对杂交竹梢枯病的防治效果。结果显示,最优培养基组成为葡萄糖5 g、甘油5 g、黄豆饼粉3 g、蛋白5 g、NaCl 2.5 g、CaCO32 g、蒸馏水1 000 mL。优化发酵培养滤液对病原菌分生孢子萌发及菌丝生长均有明显的抑制作用,可导致芽管、菌丝畸形。去菌发酵原液及其10倍稀释液处理离体枝叶能有效抑制病斑扩展,接种后4天的防治效果在70%以上。田间喷施去菌发酵原液及其5倍稀释液防治效果均达80%以上,极显著高于浓度为30 mg/mL的化学药剂50%多菌灵和70%甲基硫菌灵(P<0.01)。

Streptomyces purpeofuscus YSSPG3 with antagonistic effect on Arthrinium phaeospermum, the pathogen of hybrid bamboo blight, was isolated from rhizosphere of healthy hybrid bamboo in Sichuan. In order to confirm the potential biocontrol of antagonistic actinomycetes on plant diseases, the best liquid fermentation medium for S. purpeofuscus YSSPG3 was optimized by orthogonal array experiments. The in- hibitory effect and control efficacy of S. purpeofuscus YSSPG3 on A. phaeospermum were tested with conidi- al germination, rnycelial growth as well as lesion control in excised tissues and in field trial. The results showed that liquid fermentation medium had been screened out through optimization experiment, with in- gredients of glucose 5 g, glycerol 5 g, soybean powder 3 g, peptone 5 g, NaC1 2.5 g, CaCO3 2 g, and dis- tilled water 1 000 mL. The optimal fermentation filtrate had conspicuous inhibitory effect on conidial ger- mination and mycelial growth. It was found that the germ tube and mycelium of A. phaeospermum exhibi- ted obvious malformation after being treated with the cell-free fermentation filtrate. Development of lesions were inhibited remarkably on excised twigs and leaves which had been treated with the pure or I0 times dilution of cell-free fermentation filtrate and inoculated the mycelia cakes, the control efficacy of 4 days after inoculation was more than 70%. In the field trails, the control efficacy of spreading the pure or 5 times dilution of cell-free fermentation filtrate reached 80%, which was significantly higher than those of 50% carbendazim （30 mg/mL） and 70% thiophanate methyl （30 mg/mL） at P 〈 0. 01 level.