两株烟草黑胫病拮抗菌的筛选、鉴定和促生防病潜力评价

Screening, Identification, Biocontrol and Growth-promoting Potential Evaluation of Two Bacterial Strains against Tobacco Black Shank

烟草黑胫病在我国烟区分布广泛,严重影响烟草的产量和质量。筛选出对烟草具有防病和促生作用的细菌是有效控制烟草黑胫病危害和提高烟草产量的重要途径。通过稀释涂布平板法、对峙培养法从烟草病株根际土壤中筛选出YBM-4和YJC-4两株细菌。根据分子形态学、最适生长条件和生理生化及16S r DNA基因序列分析比对结果,鉴定YBM-4是枯草芽孢杆菌(Bacillus subtilis),YJC-4是沙福芽孢杆菌(Bacillus safensis)。在对峙培养中,YBM-4和YJC-4细菌对烟草黑胫病菌丝的相对抑制率分别是85.34%和72.99%。在盆栽试验中,YBM-4和YJC-4对烟株生物量和农艺性状的促生作用明显,YBM-4、YJC-4和YBM-4+YJC-4混剂(比例1:1)对烟草黑胫病的平均防治效果分别是76.37%、80.06%和81.50%,病程进展曲线下面积(AUDPC)分别比对照降低265.01,281.58,287.32。表明细菌YBM-4和YJC-4具有潜在的利用和开发价值。

Tobacco black shank is widely distributed in tobacco growing areas in China and has serious effects on tobacco production and quality.One of the potential control approaches against tobacco black shank is to use antagonistic bacterial.Using the culture plate dilution method,YBM-4and YJC-4,two bacterial strains were isolated from tobacco rhizosphere soil to have an antagonistic effect on tobacco black shank.Based on comprehensive analysis on morphology,biological traits and physiological and biochemical characteristics,and16S rDNA gene sequence analysis,YBM-4was identified as Bacillus subtilis and YJC-4was identified as Bacillus safensis.The two strains of YJC-4and YBM-4had significant antagonism against tobacco black shank.In paired cultures,relative inhibition rate of YJC-4and YBM-4reached85.34%and72.99%.In the pot experiment,effects of YBM-4and YJC-4on tobacco agronomic traits and biomass growth promoting were obvious.The control effects on tobacco black shank of YBM-4,YJC-4and YBM-4+YJC-4mixture(1:1ratio)were76.37%,80.06%and81.50%,with the AUDPC lower than that of the control group by265.01,281.58,and287.32respectively.YBM-4and YJC-4have a potential in bio-control of tobacco black shank.