桑氏链霉菌突变株的抑菌活性及对杨树紫纹羽病的盆栽防效

本文在平板对峙法测定桑氏链霉菌突变株MV-2和MV-4拮抗活性的基础上,用不同有机溶剂对其发酵液和菌丝体进行萃取,采用孔洞法测定发酵液萃取物和菌丝体浸出物的抑菌活性,并分析活性物质的热、酸碱、光稳定性,耐储藏性和对福美双的耐受性;通过盆栽试验,探索突变株抑菌物质和福美双对杨树紫纹羽病的防治效果。结果表明,两株突变株和原始菌株KJ40对除终极腐霉外的7种植物病原真菌均有拮抗作用,对紫纹羽丝核菌作用最强。乙酸乙酯的发酵液萃取物和菌丝体浸出物的抑菌效果最明显;突变株MV-2的抑菌效果略好于MV-4和KJ40。在稳定性检测中,突变株比原始菌株具有更好的热、酸碱、光、储藏稳定性,对福美双耐受性更强。说明突变株更适宜于生产,具有较大的开发潜力。在盆栽防效试验中,抑菌物质和福美双混合施用比单独施用效果更好,其中MV-2和福美双混合施用预防杨树紫纹羽病的效果最好,防治效果超过80%;原始菌株的抑菌物质无论和福美双混合还是单独施用,效果都不如突变株。

Antifungal activity of mutant strains of Streptomyces sampsonii and their control effects on poplar purple root disease in potted experiment

On the basis of antagonistic activity of Streptomyces sampsonii mutant strains tested with dual culture method, the fermentation liquid was extracted by different organic solvents. The antifungal activities of fermentation liquid extract and mycelium extract were studied by hole method, and the thermal, pH, ultraviolet light, storage stability, and tolerance to thiram of the active antifungal substances were analyzed. The control effect of the active substances of mutant strain and thiram was explored in potted experiments. The results showed that two mutant strains (MV 2 and MV 4) and original strain KJ40 had antagonistic effects on seven species of pathogens except Pythium ultimum, and the effect was strongest on Rhizoctonia crocorum. The antifungal effects of liquid extract and mycelium extract were also most obvious by ethyl acetate extraction. The effect of mutant strain MV 2 was slightly better than MV 4 and the original strain. In the stability testing, the mutant strain had better thermal, pH, ultraviolet light and storage stability than the original strain, and the tolerance against thiram was stronger. In the potted experiment, the effect of mixed application of antifungal substances and thiram was better than separate application, of which the incidence was lowest and control effect was more than 80% in the mixed application of MV 2 and thiram. The antifungal effect of original strain was not as good as that of the two mutant strains whether mixed with thiram or separate application.