Study on the isolation , identification and insecticidal activity of endophyte from Achnatherum inebrians

Abstract:

Abstract：[Objective] To study the endophyte species of Achnatherum inebrians and to screen strains which have insecticidal activity to 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 insecticidal activities tests by slide disc immersion and nebulization methods.[Results] A total of 89 bacteria species that classified into 8 genera of Bacillus, Streptomyces, Corynebacterium, Phyllobacterium, sphingomonnas, Paenibacillus, Pseudomonas, Acinetobacter and 2 fungi of Claviceps purpure and Claviceps Chaetomium, were isolated. Of them, the strain Streptomyces rochei (GA) and Claviceps purpurea (PF-2) were showed more than 85% of mortality to cotton aphis, after primary and second screenings. [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.

Key words:Keyword: Achnatherum inebrians; endophyte; Streptomyces rochei; Claviceps purpurea; cotton