外源酚酸对生防细菌拮抗尖孢镰刀菌西瓜专化型的影响

Effect of exogenous phenolic acids on antagonism of biocontrol bacterium on Fusarium oxysporum f.sp.niveum

为明确外源酚酸影响下生防细菌对尖孢镰刀菌西瓜专化型(Fusarium oxysporum f.sp.niveum,FON)的拮抗作用,在添加不同质量浓度邻苯二甲酸、对羟基苯甲酸、阿魏酸、肉桂酸和混合酚酸的条件下,通过室内培养试验,定期测量FON和生防细菌菌落的直径,结合对峙培养试验,计算不同外源酚酸影响下生防细菌对FON的抑菌率。结果表明:质量浓度为10~50 mg/L的邻苯二甲酸、对羟基苯甲酸、阿魏酸、肉桂酸和混合酚酸对FON的生长均具有促进作用,对生防细菌的生物活性具有抑制作用;外源添加30 mg/L以上酚酸,可显著降低生防细菌的抑菌率,最高降幅达28.19%;生防细菌菌悬液浓度越低,酚酸对抑菌率的降低作用越强;混合酚酸对生防细菌的抑制作用较相同质量浓度的单一酚酸更强。在酚酸积累的环境中施用生防细菌应适当提高生防细菌浓度,以使生防细菌对病原菌的拮抗性保持在较高水平。

In order to clarify the changes in the antagonism of biocontrol bacteria to Fusarium oxysporum f.sp.niveum(FON)under the influence of exogenous phenolic acids,the colony diameters of FON and Fusarium oxysporum were measured periodically in indoor culture tests with different concentrations of phthalic acid,p-hydroxybenzoic acid,ferulic acid,cinnamic acid and mixed phenolic acids.Combined with the standoff culture test,the inhibition rate of FON by biodefense bacteria under the influence of different exogenous phenolic acids was calculated.The results showed that 10 ~50 mg/L phthalic acid,p-hydroxybenzoic acid,ferulic acid,cinnamic acid and mixed phenolic acid all had a promotional effect on the growth of FON and an inhibitory effect on the biological activity of the biocontrol bacteria.The exogenous addition of phenolic acid above 30 mg/L significantly reduced the bacterial inhibition rate of FON,up to 28.19%;the lower the concentration of bacterial suspension of FON,the stronger the reduction of phenolic acid on the bacterial inhibition rate;the inhibitory effect of mixed phenolic acid on FON was stronger than that of single phenolic acid at the same concentration.In the environment of phenolic acid accumulation,the concentration of bacteriophage should be increased to ensure that the antagonism of bacteriophage to pathogenic bacteria is maintained at a high level.