烟草野火病拮抗生防菌的筛选、鉴定与应用

为筛选出烟草野火病拮抗生防菌,开发防治烟草野火病的新型生物农药,降低烟叶农药残留,提高烟叶的安全性,从烟田采集的健康烟草叶片经平板划线法分离和纯化后得到287个细菌分离物,从中筛选到14个对烟草细菌性野火病有抑制作用的拮抗生防菌,测得其中具有较强抑制作用的菌株抑菌带宽度为9.3 mm,经16S rDNA序列鉴定,该菌属于枯草芽孢杆菌Bacillus subtilis。烟草叶片经该拮抗菌液诱导后接种,叶片内主要防御酶苯丙氨酸解氨酶(PAL)、过氧化物酶(POD)、多酚氧化酶(PPO)活性均显著增强。防效测定表明:施用生防剂后接种野火病菌的处理,拮抗菌株防治效果达97.54%,对照农用链霉素防治效果为41.44%。先接种野火病菌后施生防剂的处理,拮抗菌株防治效果达51.40%,对照农用链霉素防治效果为50.69%。说明该拮抗菌株的预防效果高于当前生产上使用的农用链霉素,且其预防效果优于治疗效果。

Screening, Identification and Application of Antagonistic Bacteria Against Tobacco Wildfire Disease

In order to screen out antagonistic bacteria against tobacco wildfire disease,develop a new biological pesticide for preventing and controlling tobacco wildfire disease and reduce the pesticide residue in tobacco,14 strains of antagonistic bacteria against tobacco wildfire bacteria disease were screened out from 287 isolates separated from healthy tobacco leaves by way of streak on plate method.The strains were identified as Bacillus subtilis basing on 16S rDNA sequence.The inhibition zone of the most antagonistic strains was 9.3 mm in width.After spraying inoculation antagonistic bacteria to tobacco plants,the activities of phenylalanine ammonialyase(PAL),peroxide enzyme(POD) and polyphenoloxidase(PPO) in tobacco leaves increased significantly.The test results showed that the control efficiency was 97.54% for the treatment of spraying antagonistic bacteria before inoculating pathogen bacteria in contrast with 41.44% for the control(spraying agro-streptomycin).The control efficacy was 51.40% for the treatment of spraying antagonistic bacteria to tobacco plants after inoculating pathogen bacteria in contrast with 50.69% for the control(spraying agro-streptomycin).It indicated that the preventive effect of antagonistic bacteria was significantly higher than that of agro-streptomycin,and its preventive effect was better than its treatment effect.