Molecular identification of Bacillus strains isolated from extreme dry-sand environment in Qinghai Chaidamu region and its lipopeptide compound analysis

Abstract:

[Objective] Microbe resource research in extreme environment. [Methods] Eight Bacillus strains isolated from Chaidamu extreme dry-sand region in Qinghai Province, were identified by polyphasic molecular taxonomy methods including rep-PCR (BOX-PCR and ERIC-PCR) fingerprints, as well as gyrB and 16S rDNA partial sequence analysis. Antagonistic activity detection and dual culture method screening were used to check antagonistic activity and bio-control efficacy of isolates. MALDI-TOF-MS were used to analyze lipopeptide compound of strains. [Results] Eight isolates were identified as Bacillus amyloliquefaciens (6 isolates), Bacillus axarquiensis (1 isolate), Bacillus atrophaeus (1 isolate). All of the isolates presented distinct antagonistic activity and bio-control efficacy to Sclerotinia sclerotiorum. MALDI-TOF-MS results showed that the strain DGL1 (B. amyloliquefaciens) produced Fengycin, strain DGL6 (B. axarquiensis)produced Surfactin, BacillomycinsD and Fengycin, while strain DCD1 (B. atrophaeus) produced Surfactin and Fengycin. [Conclusion] The research provided Bacillus resources for further developing and application of bio-control strains adjusting in dry-sand extreme environment of Qing-Tibet Altiplano.

Key words:Qinghai Chaidamu, Dry-sand extreme environment, Isolation of Bacillus, Molecular identification, Antagonistic activity analysis