酸碱度对烟草青枯菌生长特性的影响

Effects of pH on growth characteristics of Ralstonia solanacearum in tobacco

为探究酸碱度对烟草青枯菌生长特性的影响,在混合青枯菌的不同酸碱度土壤中测定烟草青枯病的发病情况。应用qRT-PCR方法测定不同酸碱度条件下烟草青枯菌的消长动态,通过结晶紫法和半固体培养基法分别测定青枯菌的生物膜和运动性在不同酸碱度条件下的变化。结果表明:烟草青枯病在弱酸性和中性(pH 6.0~7.0)土壤中发病严重。烟草青枯菌的消长动态结果显示,青枯菌数量在pH 6.5的土壤中最多,为9.1×108cfu·g^(-1) FW。烟草青枯菌生物膜成膜能力在pH 5.5时最强,pH 7.0时最弱。pH6.5时烟草青枯菌的运动性最强,pH 8.0时最弱。土壤酸碱度通过影响青枯病菌的消长、成膜能力和运动性进而影响烟草青枯菌对烟株的侵染。

To explore the effects of pH on the growth characteristics of R. solanacearum in tobacco, the incidence of tobacco bacterial wilt in R. solanacearum-mixed soils at different pH values was analyzed. The population dynamics of R. Solanacearum at different pH values were determined by qRT-PCR, and the variations of biofilm and motility of R. solanacearum were detected by the crystal violet method and semi-solid medium method respectively. The results showed that severe tobacco bacterial wilt occurred in weakly acidic and neutral soils （pH 6.0-7.0）. The population of R. Solanacearum was maximum （9.1×10^8 cfu·g-1 FW） in the soils at pH 6.5. The biofilm formation ability of R. Solanacearum was the strongest and the weakest at pH 5.5 and 7.0, respectively. The motility of R. solanacearum was the strongest and the weakest at pH 6.5 and 8.0, respectively. Therefore, soil pH influences the infection ability of R. solanacearum by affecting the population dynamics,biofilm formation ability and motility of R. solanacearum.