辐射诱变贝莱斯芽孢杆菌及其对辣椒炭疽病抑菌效果

Radiation mutagenesis of Bacillus velezensis and its antibacterial effect on Colletotrichum gloeosporioides

采用^(60)Co-γ射线和电子束辐射诱变贝莱斯芽孢杆菌选育遗传稳定的突变菌株,用平板对峙法及四点法对突变菌株进行初筛和复筛,研究其对辣椒炭疽病菌的抑菌效果。结果表明:菌悬液经^(60)Co-γ射线辐照,贝莱斯芽孢杆菌D_(10)值为2366 Gy,在100~2000 Gy诱变剂量范围内芽孢杆菌致死率随着辐照吸收剂量的增加而升高。在2000 Gy辐照吸收剂量下,贝莱斯芽孢杆菌的致死率为81.8%,并筛选出5株(B004、B112、B114、B117、B118)突变菌株,其对辣椒炭疽病菌抑制率由出发菌株的51.2%分别提高到57.5%、58.0%、57.0%、57.7%和59.9%;贝莱斯芽孢杆菌菌悬液经电子束(10 MeV)辐照,贝莱斯芽孢杆菌D10值为499 Gy,在100~600 Gy诱变剂量范围内,芽孢杆菌致死率随着辐照吸收剂量的增加而升高,在400 Gy辐照吸收剂量下,贝莱斯芽孢杆菌致死率为91.8%,筛选出2株(D115和D243)突变菌株,其对辣椒炭疽病菌抑制率由出发菌株的55.2%分别提高到58.4%和58.1%;B004、B112、B117、B118贝莱斯芽孢杆菌诱变菌株对辣椒炭疽病菌抑菌效果在6代内遗传稳定。研究结果表明:γ射线和电子束辐照在贝莱斯芽孢杆菌的诱变育种中具有潜在的应用价值,本研究可为贝莱斯芽孢杆菌的诱变育种提供基础,为辣椒炭疽病病害的生物防治提供理论参考。

We used^(60)Co-γray and electron beam irradiation to mutate Bacillus velezensis to breed genetically stable mutant strains.The mutant strains were screened and re-screened by plate confrontation and the four-point method to study their antibacterial effects on Colletotrichum gloeosporioides.The results demonstrated that the D10 value of Bacillus velezensis suspension irradiated by^(60)Co-γray was 2366 Gy,and the lethality rate increased with an increase in the irradiation coefficient dose in the range of 100−2000 Gy.The lethality rate of Bacillus velezensis was 81.8%at 2000 Gy irradiation coefficient dose,and five mutants(B004,B112,B114,B117,and B118)were screened.The inhibition rate against Colletotrichum gloeosporioides increased from 51.2%of the original strain to 57.5%,58.0%,57.0%,57.7%,and 59.9%,respectively.The Bacillus velezensis suspension was irradiated by an electron beam(10 MeV),the D10 value was 499 Gy,and the lethality rate increased with an increase in the irradiation coefficient dose in the range of 100−600 Gy.The lethality rate of Bacillus velezensis was 91.8%at 400 Gy irradiation coefficient dose.Two mutant strains(D115 and D243)were screened,and their inhibition rates against Colletotrichum gloeosporioides increased from 55.2%of the emitted strains to 58.4 and 58.1%,respectively.The inhibitory effects of B004,B112,B117,and B118 mutants on Colletotrichum gloeosporioides were genetically stable within six generations.In conclusion,γ-ray and electron beam irradiation have potential application value in the mutation breeding of Bacillus velezensis.The results provide a basis for Bacillus velezensis mutation breeding and a theoretical reference for the biological control of Colletotrichum gloeosporioides.