目的 筛选得到能够防治白术Atractylodes macrocephala根腐病的内生细菌。方法 采用传统分离法从白术健康组织中分离内生细菌，以白术根腐病菌尖孢镰刀菌Fusarium oxysporum，茄病镰刀菌F.solani和半裸镰刀菌F.incarnatum为指示菌，采用平板划线法和滤纸片法筛选拮抗细菌；制备拮抗菌菌悬液，采用灌根法进行盆栽白术根腐病防效试验；通过细菌形态特征、生理生化检测及16S rRNA技术对拮抗细菌进行菌种鉴定。结果 从白术组织中共分离得到246株内生细菌，平板对峙筛选得到抗根腐内生细菌18株，其中AM14对3种病原菌生长均具有显著抑制作用（P<0.05），平均抑菌率达80.68%；盆栽试验进一步表明AM14对白术根腐病具有较好的防治效果，防治效果达70.49%；经鉴定AM14为芽孢杆菌属细菌Bacillus sp.。结论 内生细菌AM14具有良好的白术根腐病生防潜力。

Objective To screen candidate antagonistic bacteria for the control of Atractylodes macrocephala root-rot disease. Methods The traditional dilution plate method was used to isolate endophytic bacteria from A. macrocephala. Root-rot pathogenic fungi, including Fusarium oxysporum, F. solani and F. incarnatum, were used as indicator fungi, and the antagonistic bacteria were screened by the plate and filter paper confrontation method. The antagonistic bacterium suspension was prepared and its biological control for A. macrocephala root-rot disease was observed by root filling method. The antagonistic bacterium was identified via the bacterial morphological characteristics, physiological and biochemical detection, and 16S rRNA sequence analysis. Results A total of 246 endophytic bacteria were isolated from A. macrocephala and 18 antagonistic strains against root-rot pathogen were obtained. Moreover, endophytic bacteria AM14 strains had superior inhibition effects on the growth of three pathogenic fungi (P<0.05), with an average inhibitory rate of 80.68%. Pot experiment suggested that AM14 had a better control effect on A. macrocephala root-rot disease with 70.49% of the control efficiency. Further, AM14 was identified as Bacillus sp. Conclusion Endophytic bacterium AM14 (Bacillus sp.) can be used as the candidate strains for biological control for A. macrocephala root-rot disease.

R286

国家自然科学基金项目（82003896）