贵州半夏块茎腐烂病拮抗细菌的筛选与鉴定

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

【目的】从半夏根际土壤筛选对半夏块茎腐烂病致病菌有拮抗活性的细菌并进行鉴定。【方法】采用稀释分离法和平板对峙法分离拮抗菌,然后根据菌落形态、生理生化特性,结合分子生物学方法进行鉴定。【结果】从半夏根际土壤共分离到228株细菌,其中菌株GZDF2、GZDF3、GZDF4对病原细菌及病原真菌均有拮抗活性,抑菌圈大小达23 mm,并且抑菌谱广。经形态学观察、生理生化特性分析和分子生物学方法,将菌株GZDF2、GZDF3、GZDF4鉴定为短短芽胞杆菌(Brevibacillus brevis)。进一步采用gyr B和rpo B基因对3株短短芽胞杆菌进行聚类分析,结果显示GZDF3菌株与其他2株短短芽胞杆菌存在遗传差异。【结论】半夏根际土壤中分离到的3株短短芽胞杆菌抑菌活性强、抑菌谱广,具有开发成生防剂的潜力。

[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 and16 S r RNA 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 on23 mm and had a broad spectrum antibacterial activity GZDF2, GZDF3 and GZDF4 were identified as Brevibacillus brevis according to its＇ morphological, physiological and biochemical characteristicsand 16 S r RNA gene sequences. Phylogenetic analysis based on gyr B and rpo B 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.