Screening and identification of antagonistic bacteria against soft rot of Pinellia ternata in Guizhou Province

Abstract:

[Objective] To screen and identify antagonistic bacteria against the soft rot of Pinellia ternata from it’s rhizosphere soil. [Methods] Antagonistic bacteria were isolated by serial dilution and dual culture, and then identified by respective morphological and biochemical characteristics and 16S rRNA gene sequences. [Results] Total 228 strains of bacteria were isolated from the rhizosphere soil of Pinellia ternata, and three strains named as GZDF2, GZDF3 and GZDF4 among them showed the strong antagonistic activities to pathogens of Pectobacterium carotovorum subsp. carotovorum and Fusarim oxysporum and Fusarium solani with diameters of inhibition zone on 23 mm and had a broad spectrum antibacterial activity GZDF2, GZDF3 and GZDF4 were identified as Brevibacillus brevis according to its’ morphological, physiological and biochemical characteristics and 16S rRNA gene sequences. Phylogenetic analysis based on gyrB and rpoB sequence showed that GZDF3 was geneticly different from other two strains. [Conclusion] Three strains (GZDF2, GZDF3 and GZDF4) isolated from rhizosphere soil of Pinellia ternata showed potential to develope for biocontrol agents.

Key words:Pinellia ternata, Soft rot, Antagonistic bacteria, 16S rRNA gene, gyrB, Biocontrol agents