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

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

摘要

本文在平板对峙法测定桑氏链霉菌突变株MV2和MV4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MV2的抑菌效果略好于MV4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MV2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。

关键词

桑氏链霉菌；突变菌株；抑真菌作用；防治效果

中图分类号：

S 763.15

文献标识码：A

DOI：10.3969/j.issn.05291542.2015.05.010

Abstract

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 （MV2 and MV4）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 MV2 was slightly better than MV4 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 MV2 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.

Key words

Streptomyces sampsonii；mutant strain；antifungal effect；control effect

随着对环境健康、食品安全的重视，逐步降低化学农药用量是控制植物病害的趋势。由此，开发高效低毒、环境兼容性好的替代化学杀菌剂的新型生物农药是目前国内外植物保护领域研究的热点之一[12]。尽管如此，由于生防微生物种群的繁殖易受到环境温度、湿度、土壤pH等诸多因素的影响，药效反应慢，作用效果大多不明显甚至无效[34]。有报道指出[5]，生防微生物和化学农药混合使用，不仅可以降低化学农药的使用量，减轻对环境的污染，还因为化学杀菌剂削弱了病原菌的生长，使其对生防菌更加敏感，从而提高了生防微生物的防治效果。因此，生物农药的研究和开发要根据现有的基础和优势有针对性地发展。紫纹羽病又称紫色根腐病，是由紫纹羽丝核菌（Rhizoctonia crocorum Fr.）引起的一种苗木病害。该菌寄主范围广泛，达45科，76属，100多种，包括松、柏、杉、刺槐、杨、榆、桑、柳、苹果等，是一种重要的土传病原菌。利用生防微生物防治紫纹羽丝核菌的研究，在国内外还未见报道。

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