烟草内生细菌Itb295对黑胫病菌的抑制及其鉴定

目的]确定分离自健康烟草植株的内生细菌Itb295的分类地位和生防潜能。方法]通过平板对峙培养法测定菌株Itb295对烟草黑胫病菌的抑制作用,并结合菌株形态、生理生化特性和16S rDNA序列(GenBank登录号JF496206)比对分析确定该菌株的分类地位。结果]鉴定Itb295菌株为枯草芽孢杆菌Bacillus subtilis。菌株Itb295对黑胫病菌菌丝生长抑制率为34.64%,受抑制的黑胫病菌菌丝膨大、扭曲、分支增多,不能正常生长,抑菌效果的可逆性分析显示受抑制的菌丝在OA培养基上能够正常生长。结论]为烟草黑胫病的防治及内生细菌Itb295的进一步研究提供了理论依据。

Identification and Inhibition of Tobacco Endophytic Bacteria Strain Itb295 against Black Shank Pathogens

Objective] The aim was to deter mine taxonomic taxa and potential application of endophytic bacteria Itb295 obtained from healthy tobacco plants. Method] The inhibitory ability of Itb295 against Phytophthora nicotianae was investigated with dual-cultured. The Itb295 was i- dentified according to morphological,physiological and biochemical characteristics, and 16S rDNA （GenBank accession JF496206） phylogenetic analysis. Result ] Itb295 was identified as Bacillus subtilis. The Itb295 significantly inhibited the mycelial growth of P. nicotianae with average in- hibition rate as 34.64%. The mycelia of P. nicotianae treated with hb295 had a compact branch and showed swollen and distortion. Antibacterial effect of the reversibility analysis showed inhibition of hyphae on excluding medicine tablet could normal growth. Conclusion] The research re- suits provide theoretical basis for the control of black shank pathogens and further study on endophytic bacteria Itb295.