耐福美双桑氏链霉菌生物型的选育

Mutation Breeding of Thiram-Resistant Mutants Streptomyces sampsonii

为选育抗药性桑氏链霉菌(Streptomyces sampsonii),采用紫外线照射与药物培养基驯化结合法,筛选出MV-1、MV-2、MV-3、MV-4、MV-5等5株能在含有200 mg/L福美双的培养基上生长的抗性突变株。结果显示:出发原菌株KJ40对福美双最敏感,EC50为12.82 mg/L,致死浓度为40 mg/L。5株突变株中,MV-2和MV-5的EC50值最高,为129.28 mg/L,抗性水平最高,达10.09;MV-1最低,EC50为100.13 mg/L,抗性水平7.81。通过抑菌效果测定发现,MV-2和MV-4对紫丝核菌(Rhizoctonia crocorum)抑菌力显著高于KJ40,抑菌率为80.39%和76.08%,分别比KJ40提高了10.59%和6.28%;MV-5无抑菌效果;MV-1和MV-3对病原菌的抑菌效果与KJ40无显著差异。拮抗活性高于亲本的MV-2和MV-4与福美双协同使用,抑菌效果高于菌株和福美双药液单独使用。

We screened out five mutation strains resistant to thiram of MV-1, MV-2, MV-3, MV-4 and MV-5 by the combination methods of UV irradiation and medical cultivation to select the thiram-resistant mutants of Streptomyces sampsonii. Among the tested strains of Streptomyces sampsonii, KJ40 was the most sensitive to thiram, the ECs0 was 12.82 μg/mL, the lethal concentration was 40 μg/mL. The resistant level of MV-2 and MV-5 were the highest between the thiram-resistant strains, and the ECs0 and the resistant level were 129.28 μg/mL and 10.09, respectively. The resistance level of MV-1 was the lowest, and the ECs0 and the resistant level were 100.13 μg/mL and 7.81, respectively. By determining inhibiting effect, inhibition activities of MV-2 and MV-4 were more significant than their parental strains, and the inhibition rate reached 80.39% and 76.08%, respectively. Compared with KJ40, the inhibition rates were improved by 10.59% and 6.28%, respectively. MV-5 had no antibacterial effect on Rhizoctonia crocorum. Compared with the parental strains, there were no significant changes in inhibition activities of mv- 1 and my- 3. By using the mixed of Thiram and Thiram-resistant mutants with the strongest inhibition activity, the inhibiting effect was more than that of thiram-resistant mutantsor and thiram alone.