3株放线菌对白菜根肿病的防治效果及机制研究

研究3株放线菌对白菜根肿病的防治效果,以挖掘具有良好防治效果的生防菌株。以前期分离筛选的2株优良生防放线菌株(Streptomyces pactum Act12和Sr.ochei D74)与1株分离自根肿病发病小区健株根际土中的黄白链霉菌(S.alboflavus SP12)为研究对象,利用孢子萌发、皿内发芽及盆栽试验研究不同菌株对白菜根肿病的防治效果及机制。结果表明:(1)SP12与D74接种可显著降低根肿病的发病率与病情指数,发病率分别降低50.0%和41.7%,病情指数分别降低20.3%和19.4%;SP12与D74提高白菜地下部分鲜质量36.6%和8.6%,同时地上部分鲜质量分别增加25.4%和4.9%。(2)SP12与D74显著影响白菜生长及抗性相关生理生化指标:SP12与D74使根系活力分别增加46.2%和34.4%,PPO活力分别增加49.0%和66.5%,脯氨酸含量分别增加11.2%和35.1%,丙二醛含量分别降低5.2%和7.4%;SP12处理可提高POD活性26.4%(P0.05)。(3)SP12和D74可改变白菜根际土壤微生物群落结构组成,提高放线菌的数量63.7%和15.4%。结果表明:SP12、D74对根肿病防治、植株生长、抗逆酶系统及根际微生态均有良好的促进作用。

Effects of 3 Biocontrol Strains on Clubroot Disease-resistant and Mechanism in Chinese Cabbage

The biocontrol effects of five strains against clubroot was conducted to explore biocontrol strains with good control effect.Two excellent biocontrol strains(Streptomyces pactum Act12 and Streptomyces rochei D74) and Streptomyces alboflavus SP12, which isolated from the rhizosphere soil of a healthy cabbage plants in the clubroot infected area were studiedin this paper.The control effect and mechanism of different strains were done by spore germination test, dish germination test and pot experiment. The results showed that: (1) SP12 and D74 could significantly reduce the incidence of clubroot by 50.0% and 41.7% respectively, and the disease index by 20.3% and 19.4% respectively. SP12 and D74 increased the underground fresh mass of Chinese cabbage by 36.6% and 8.6%, and the aboveground part by 25.4% and 4.9% respectively. Act12 had no effect on the incidence of clubroot disease, but it could promote the fresh mass of cabbage above ground and underground. (2) SP12 and D74 significantly affected the physiological and biochemical indexes related to plant growth and resistance: SP12 and D74 significantly increased root activity by 46.2% and 34.4%, PPO activity by 49.0% and 66.5%, proline content by 11.2% and 35.1%, and MDA content by 5.2% and 7.4%, respectively. Act12 and SP12 treatment could improve POD activity by 19.6% and 26.4%. (3) SP12 and D74 could change the structure of soil microbial community in the Chinese cabbage rhizosphere, and increase the number of actinomycetes by 63.7% and 15.4%. SP12 and D74 had remarkable biocontrol and promotion effect, and could improve anti-reverse enzyme activity and rhizosphere microecology. The results provide excellent strains and the theoretical basis for the biocontrol of clubroot.