一株具有杀虫活性链霉菌的研究

Study on the insecticidal activity of a Streptomyces strain

通过卤虫初筛和花布灯蛾幼虫复筛,从土壤中获得1株具有较高杀虫活性的链霉菌,编号为LKY208,为明确该菌株的生防效果及分类地位,采用叶片浸渍法、饲料染毒法、玻片浸渍法及常规浸虫法分别测定了其对花布灯蛾、美国白蛾、小菜蛾、菜青虫、亚洲玉米螟、二斑叶螨、马铃薯瓢虫、桃蚜8种农林害虫的杀虫活性;并对该菌株发酵液的稳定性进行了初步研究,同时通过形态学和16S rDNA序列分析初步确定了其分类地位。结果表明:该菌株对8种试虫均有致死作用,杀虫谱广,其中对花布灯蛾的致死作用最强,48 h的校正死亡率达72.1%,菌株发酵液对温度耐受性强,在25~50℃杀虫活性稳定;pH 4~7范围内菌株杀虫活性较好,发酵液有较好的光稳定性、贮存稳定性和菌株遗传稳定性,具有较好的开发应用价值;经形态学和16S rDNA序列分析,初步鉴定菌株LKY208为雷格链霉菌Streptomyces regensis,此乃国内外首次报道将链霉菌应用于花布灯蛾的防治。

Strain LKY208 with a good insecticidal activity was isolated from soil by using Artemia salina and Camptoloma interiorata. In order to clarify the biocontrol effect and taxonomic status of the strain LKY208, the insecticidal activity of fermented broth of LKY208 against 8 pests was determined by leaf-dipping method, feeding with poison, slide-dip method and conventional dipping method. Meanwhile, the stability of fermentation broth was also studied. The taxonomic identification was carried out by the morphology and 16 S rDNA sequence. The strain LKY208 displayed broad-spectrum inhibition activity against all the 8 pests tested, including Camptoloma interiorata, Hyphantria cunea, Plutella xylostella, Ostrinia furnacalis, Pieris rapae, Tetranychus urticae,Henose-pilachna vigintioctomaculata and Myzus persicae. The results showed that the insecticidal effect on C.interiorata was the strongest, with a relative mortality of 72.1% after 48 hours. The fermented broth showed a high resistance to temperature and a highly insecticidal activity was still observed at the temperature of 25-50℃. In the range of pH 4-7, its insecticidal activity was good, with a good photochemical stability, storage tolerance and subculture, and thus it deserved further study. On the basis of morphology and 16S rDNA sequence analysis, it was identified as Streptomyces regensis. This is the first report that Streptomyces regensis was applied for the control of C.interiorata.