黄麻链霉菌NF0919菌株发酵提取液HPLC检测分析及稳定性研究

采用HPLC法检测分析了黄麻链霉菌NF0919菌株发酵提取液的主要有效成分,以确定该发酵液的HPLC检测方法,采用菌丝生长速率法对不同处理条件下的发酵提取液进行抑菌活性测定,以确定该发酵提取液的稳定性。结果表明,在采用C18柱,波长305 nm,甲醇与水梯度洗脱的条件下,所检测到的发酵提取液物质成分最多;该菌株发酵提取液对热、碱、紫外线的稳定性较差,对酸、光照均较稳定,在冰箱贮藏条件下,该菌株的发酵提取液稳定性较强,具有一定的研究开发价值。

黄麻链霉菌NF0919菌株对草莓枯萎病的生防活性初探

采用菌丝生长速率法测定了黄麻链霉菌NF0919发酵液对草莓枯萎病菌的室内毒力,并进行了防治草莓枯萎病的室内盆栽试验。结果表明:NF0919菌株发酵液和申嗪霉素对草莓枯萎病菌菌丝生长抑制的EC50值分别为24.3752和0.4001μg/mL;NF0919菌株发酵上清20倍液和1%申嗪霉素SC 800倍液药后30 d对草莓枯萎病的防效分别为65%和90%。

黄麻链霉菌NF0919菌株发酵培养基的优化

以黄麻链霉菌(Streptomyces corchorusii)NF0919菌株发酵液对草莓炭疽病菌(Glomerella cingulata)的抑菌率为效价指标。通过单因素试验筛选出NF0919菌株发酵用最佳的碳源、无机盐和氮源,在此基础之上,再通过正交试验和二次通用旋转组合设计试验,对NF0919菌株发酵培养基进行优化。结果表明:与发酵初始培养基相比,优化后得到的最佳培养基发酵液对草莓炭疽病菌的相对毒力效价提高了13.77倍。筛选得到的最佳发酵培养基组成为:10.2%马铃薯淀粉、2.6%棉籽蛋白、0.1%CaCO3、0.05%K2HPO4、0.05%MgSO4。

黄麻链霉菌NF0919菌株对水稻纹枯病的生防活性

为研发新的水稻纹枯病生防药剂,通过室内离体毒力和活体生防活性测定以及田间试验,分析了黄麻链霉菌(Streptomyces corchorusii)NF0919菌株发酵液粗提取物(CE)对水稻纹枯病菌(Thanatephorus cucumeris)的生防活性。结果表明,CE对水稻纹枯病菌的室内抑制毒力较强,其抑制中浓度(EC50)值为0.327 7 mg/L,相比之下,对照抗菌素(井冈霉素)对水稻纹枯病菌的室内抑制毒力较低,其EC50值达到3.078 7 mg/L;CE对水稻纹枯病的保护作用强于井冈霉素,但无抗扩展作用;CE在高施用浓度(256 mg/L)下与相同浓度的井冈霉素田间防治效果相当(均达90%以上);受CE抑制的水稻纹枯病菌菌丝变成畸形并失去侵染水稻植株的能力。可见,CE对水稻纹枯病菌的室内毒力强,田间防治效果与井冈霉素相当。

4种杀菌剂对葡萄霜霉病菌的毒力及田间防效

为探明黄麻链霉菌NF0919菌株和枯草芽孢杆菌DJ-6对葡萄霜霉病的生防活性,采用叶盘法分别测定黄麻链霉菌NF0919发酵上清液、1.0×10^(11)cfu/g枯草芽孢杆菌DJ-6 WP、代森锰锌和烯酰吗啉对葡萄霜霉病菌的室内毒力,并进行防治葡萄霜霉病的田间试验。结果表明:NF0919菌株发酵上清液、1.0×1011cfu/g枯草芽孢杆菌DJ-6 WP、代森锰锌和烯酰吗啉对葡萄霜霉病菌孢子萌发抑制的EC_(50)值分别为96.2859、86.6038、69.9472、7.2636μg/m L。NF0919菌株发酵20倍液和1.0×10^(11)cfu/g枯草芽孢杆菌DJ-6WP1000倍液对葡萄霜霉病做预防性施药时,2次药后7天的防效分别为71.55%和70.71%,2次药后14天的防效分别为67.54%和68.19%;当做治疗性施药时,2次药后7天的防效分别为59.72%和56.07%,2次药后14天的防效分别为56.88%和57.46%。2种供试生防菌剂的防效相当,且保护效果与50%代森锰锌WP 300倍液均差异不显著,而治疗效果与40%烯酰吗啉SC 200倍液均差异显著。可见,黄麻链霉菌NF0919菌株和枯草芽孢杆菌DJ-6 WP对葡萄霜霉病具有一定的生防潜力与开发的价值。

Toxicity Test and Field Control Effects of 4 Different Fungicides on Grape Downy Mildew

[Objective] This study was conducted to investigate the biocontrol activity of Streptomyces corchorusii strain NF0919 and Bacillus subtilis D J-6 WP to grape downy mildew. [Methed] We determined the indoor toxicity of the supernatant of S. corchorusii strain NF0919, 1.0×1011 cfu/g B. subtilis D J-6 WP, mancozeb and dimethomorph on Plasmopara viticola by the leaf disc method, respectively, and a field efficacy trial was conducted. [Result] The results showed that the ECso values of the supernatant of strain NF0919, 1.0×1011cfu/g B. subtilis D J-6 WP, mancozeb and dimethomorph were 96.285 9, 86.603 8, 69.947 2 and 7.263 6 μg/ml, respec- tively. The values of field efficacy in preventive experiments for grape downy mildew on the 7th day after 2 times of spraying 20 times diluent of the supernatant of strain NF0919 and 1 000 times diluent of 1.0×1011 cfu/g B. subtilis D J-6 WP were 71.55% and 70.71%, respectively, and the values of field efficacy on the 14th day after the 2 times of fungicide application were 67.54% and 68.19%, respectively. The values of field efficacy in curative experiments on the 7th day after 2 times of spraying 20 times diluent of the supematant of strain NF0919 and 1 000 times diluent of 1.0×1011 cfu/g B. subtilis D J-6 WP were 59.72% and 56.07%, respectively, and the val- ues of field efficacy on the 14th day after the 2 times of fungicide application were 56.88% and 57.46%, respectively. The field efficacy values of the 2 tested biocon- trol agents were equivalent. The protective effect showed no significant difference between each of tested biocontrol agents and 300 times diluent of 50% mancozeb WP, but there was a significant difference in the efficacy between each of tested biocontrol agents and 200 times diluent of 40% dimethomorph SC. [Conclusion] The S. corchorusii strain NF0919 and B. subtilis D J-6 WP had certain biocontrol poten- tial to grape downy mildew and development value.