【摘要】 为烟草根腐病生防菌剂的研发储备菌株资源。以烟草根腐病菌为靶标，筛选拮抗菌，通过培养形态、生化特征和分子技术鉴定菌株。用平板划线测定拮抗菌耐受力，盆栽试验验证其对病害的防效。筛选出拮抗菌GDND-2，其10%和20%发酵滤液对病菌生长抑制率为53.09%和62.24%。鉴定GDND-2为贝莱斯芽孢杆菌(Bacillus velenzensis)，该菌抑菌谱广，耐极端温度、酸碱和盐碱，对多菌灵等7种常用杀菌剂不敏感。GDND-2发酵液处理15、30、45 d，对烟草根腐病的防效为70.00%、74.62%和79.51%，处理45 d的防效高于多菌灵。贝莱斯芽孢杆菌GDND-2抗菌谱广，性状优良，可有效防治烟草根腐病，有望开发为生防菌剂。更多还原

【Abstract】 The study was to reserve resources for the development of new biocontrol agents to control tobacco Fusarium root rot. The antagonistic strains were screened against Fusarium oxysporum, and were identified throgh morphological, biochemical characteristics and molecular technique. The tolerance of the antagonistic strain was determined by plate scribing method, and its control effect on tobacco root rot was verified by potting experiment. The antagonistic strain GDND-2 was screened. Its fermentation filtrate had a strong inhibitory effect on mycelium growth of F. oxysporium, the inhibition rates of 10% and 20% fermentation filtrate were53.09% and 62.24%. The strain GDND-2 was identified as Bacillus velenzensis. It presented a broad inhibitory spectrum, and showed strong tolerance to extreme temperature, acid-alkali and salt. It was not sensitive to seven commonly used fungicides such as carbendazim. The control effects of fermentation broth of GDND-2 on tobacco root rot were 70.00%, 74.62% and 79.51% on the 15^th, 30^thand 45^thday after root drenching, and its control effect on the 45^thday was higher than carbendazim. Bacillus velenzensis GDND-2 with excellent traits and broad inhibitory spectrum could effectively control tobacco Fusarium root rot, and it is expected to be developed as a biocontrol agent.更多还原