番茄青枯雷尔氏菌强致病力菌株变异的研究

摘要

In order to study the variation of Ralstonia solanacearum virulent strains isolated from tomato,the influence of subculture times,different culture time on NB medium,different pH in 7 d and 15 d treatments,1 h treatment at different temperatures on the variation of virulent strains were investigated.The results showed that the average attenuation index raised with the increasing of subculture generation,and avirulent strain appeared in the tenth generation.Virulent strains had been completely transformed to uncertain virulent strains and avirulent strains after 15 d on NB medium,and then al-most became avirulent strains after 30 d.Virulent strains accounted for the largest proportion after 7 d and 15 d cultiva-tion under pH7.0,the rates were 93.33%,92.22% respectively.On the contrary,virulent strains occupied the least pro-portion under pH5.8 with the percentage of 46.67%,31.1% respectively.When virulent strains were treated by the dif-ferent temperatures,the strains dead at 50 ℃.And when the temperature was 40 ℃,the number of live strains was sig-nificantly lower and the virulent strains were at lower ratio than any other temperature(4-30 ℃).%为研究番茄青枯雷尔氏菌强致病力菌株的变异,探索了继代培养、在 NB 培养基上不同时间培养、不同 pH 处理7 d 和15 d、不同温度处理1 h 后对强致病力菌株变异的影响.结果表明：随着继代培养的培养代数增加,平均弱化指数成增大趋势,在第10代出现了无致病力菌株；在 NB 培养基上培养15 d 时,强致病力菌株已完全转化为不确定菌株和无致病力菌株,在培养30 d 时,强致病力菌株几乎完全转化为无致病菌株；pH7．0时,处理7 d 和15 d 后,强致病力菌株比例均为最大,分别为93．33％和92．22％,pH5．8时,强致病力菌株比例最低,分别为46．67％和31．11％；用不同温度处理强致病力菌株发现,温度50℃时,菌株死亡,温度40℃时,活菌数显著低于其他(4~30℃)处理,强致病力菌株比例为4~40℃所有处理中最低.