内生菌B47的定殖能力及其对番茄青枯病的防治作用

Analysis on the colonization of entophytic bacteria B47 and its control on tomato bacterial wilt

从番茄茎分离的内生枯草芽孢杆菌菌株B47对番茄青枯病有较好的防治作用，利用该菌株的抗链霉素突变菌株，研究其在土壤和番茄植株根、茎中的定殖能力及其对番茄青枯病的防治作用。结果表明，枯草芽孢杆菌菌株B47可在土壤和番茄植株中定殖。B47施到土壤中后的15—45天，其数量逐步增加，45天后，其数量逐步下降。B47在土壤中的定殖能力随土壤的种类和土壤的处理情况而异。施入菜地土后的第45天，B47在非灭菌土中的数量是9．91×10^5cfu／g土壤干重，而在灭菌土中的数量是9．84×10^7cfu／g土壤干重。接种后，番茄植株根和茎中的B47数量，从苗期到结果期逐渐增加，但到了成熟期呈下降趋势。B47和番茄青枯病菌混合施入土壤后，随B47的数量增加番茄青枯病菌的数量显著降低。当番茄植株根和茎中B47的含量分别为1．17×10^4cfu／g鲜重和3．33×10^4cfu／g鲜重时，接种番茄青枯病菌后的第20天，对番茄青枯病的防治效果达79．79％．

Endophytic Bacillus subtilis strain B47, which was isolated from the stem of tomato, was an efficient biological control agent on tomato bacterial wilt. A strain resistant to streptomycin derivative of wild strain B47 was used to study the colonization ability and fluctuation of populations in soil and tomato organs, and its biological control on tomato bacterial wilt. The result indicated that strain B47 could colonize in both soil and tomato organ. After being inoculated in soil, the population of strain B47 increased gradually from the 15th day to 45th day, and then decreased after 45 days. The colonization ability of strain B47 in soil varied with the treatments and types of soil. The population of strain B47 in sterile garden soil was 9.84×10^7 cfu/g, however, the population in raw garden soil was 9.91×10^5 cfu/g on 45th day after being inoculated. After dipping root inoculation treatment, the population of strain B47 inside roots and stems increased gradually from the seedling stage to fruit setting stage, and then decreased after ripening stage. With the increasing of the population of strain B47, the population of Ralstonia solanacearum decreased significantly while they were mixed at a similar population in the inoculation into soil. The control efficacy on tomato bacterial wilt was 79.79% on 20th day after being inoculated with Ralstonia solanacearum by root dip when the population of strain tM7 inside roots and stems of tomato plant was 1.17×10^4 cfu/g FW （fresh weight） and 3.33×10^4 cfu/g FW, respectively.