醉马草内生菌的分离、鉴定及杀虫效果

【目的】探明醉马草内生菌的种类,筛选对农作物虫害有毒杀作用的菌株。【方法】采用研磨法从健康醉马草植物的根、茎、叶和种子中进行菌种分离;通过对其形态、培养特征、生理生化及其他生物学特性的研究;16SrDNA及ITS序列的系统发育学分析进行鉴定;用玻片浸渍法和喷雾法筛选产杀虫活性物质菌株。【结果】获得细菌89株,分别属于枯草芽孢杆菌属(Bacillus)、链霉菌属(Streptomyces)、棒状杆菌属(Corynebacterium)、叶杆菌属(Phyllobacterium)、鞘脂单胞菌属(Sphingomonnas)、类芽孢杆菌(Paenibacillus)、假单胞菌属(Pseudomonas)和不动杆菌属(Acinetobacter)8个属;真菌2株,分别属于麦角菌属(Claviceps)和毛壳菌属(Chaetomium)。经初筛及复筛,内生菌娄彻氏链霉菌Streptomyces rochei(GA)和黑麦麦角菌Claviceps purpurea(PF-2)发酵液粗提物对棉蚜虫(Aphis gossypii)致死率达85%以上。【结论】醉马草内生菌株PF-2和GA的粗提代谢物对棉蚜虫有明显的毒杀作用,为开发新的生物源农药提供了生物源物质。

Isolation, identification and insecticidal activity of endophyte from Achnatherum inebrians

Objective]To study endophyte species of Achnatherum inebrians and to screen strains with insecticidal activity against cotton insect.Methods]We isolated endophytic from roots, stems,leaves and seeds of health A.inebrians by grinding separation method and identified by a dual approach of morphological and physiological observation and 16S rDNA gene (for bacteria) and ITS sequence (for fungi) based molecular identification.Then,those endophytes were inoculated into liquid media for fermentation and the crude extracts were used to test insecticidal activities by slide disc immersion and nebulization methods.Results]We isolated bacteria species classified into 8 genera of Bacillus, Streptomyces,Corynebacterium , Phyllobacterium, sphingomonnas , Paenibacillus , Pseudomonas , Acinetobacter and 2 fungi of Claviceps purpure and Claviceps Chaetornium.Of them ,the strain Streptomyces rochei (GA) and Claviceps purpurea (PF-2) had more than 85% of mortality to cotton aphis.Conclusion]Two strains of PF-2 and GA associated within the A.inebrians had significant insecticidal activity to cotton aphis (Aphis gossypii) , which may provide a new biological resource to explore new microbial insecticide.