马铃薯真菌病害拮抗菌株鉴定及初步应用

针对马铃薯真菌病害发生严重、多种病害混合发生、缺乏安全有效防治方法的问题，对前期筛选出的高效拮抗 菌株BA-26 进行分类鉴定，研究其胞外代谢产物的稳定性，明确防病促生作用。通过形态特征、生理生化特性鉴定以及 16S rDNA 序列分析，BA-26 菌株为解淀粉芽孢杆菌（Bacillus amyloliquefaciens），该菌株对8 种马铃薯病原真菌均表现出 较强的拮抗作用，对茄链格孢菌（Alternaria solani）、茄病镰刀菌（Fusarium solani）、燕麦镰刀菌（Fusarium avenaceum） 的抑菌率大于80%；胞外代谢产物经100 ℃处理30 min、紫外照射8 h、pH 2～10 酸碱处理、蛋白酶处理1 h 后，相对抑菌 率均维持在80% 以上；室内抑菌活性测定结果表明BA-26 滤液对茄病镰刀菌的抑制率为91.3%；盆栽试验中，每盆施用 20 mL 浓度为4.0×10⁹ cfu · mL^-1 的BA-26 发酵液使马铃薯根长、须根数、株高、叶片中叶绿素含量分别显著增加32.07%、 111.94%、48.0%、19.6%。表明解淀粉芽孢杆菌BA-26 对马铃薯真菌病害抑菌谱宽，胞外代谢产物稳定性强，有较强的防病 促生作用，具有开发为马铃薯专用生防菌剂的潜力。

Identification and Preliminary Application of Antagonistic Strains Against Potato Fungal Diseases

Aiming at the issues of serious occurrence of potato fungal diseases，mixed occurrence of various diseases，lacking effective control methods，this paper classified and identified highly effective antagonistic strain BA-26 screened out at earlier stage，studied the stability of its extracellular metabolites， and clarified its role on preventing disease and promoting growth．BA-26 strain was identified as Bacillus amyloliquefaciens，through analyzing morphologic characteristics，physiological and biochemical properties， and 16S rDNA sequence analysis．This strain showed strong antagonistic effects on 8 potato pathogenic fungus，and its inhibition ratio against Alternaria solani，Fusarium solani and Fusarium avenaceum was over 80%．After treating the extracellular metabolites by 100 ℃ for 30 min，UV irradiation for 8 hours，pH 2-10 acid-base，and protease for an hour，its relative antibacterial activities were all maintained above 80%． Laboratory test of bacteriostatic activity showed that the inhibition ratio of BA-26 filtrate against Fusarium solani was 91.3%．In pot experiment，the potato root length，fibrous root number，plant height and chlorophyll content in leaves were significantly increased by 32.07%，111.94%，48.0% and 19.6%， respectively by applying BA-26 fermentation broth with 20 mL concentration of 4.0×10⁹ cfu·mL^-1 per pot． The results indicated that B. amyloliquefaciens BA-26 had broad bacteriostasis spectrum，strong stability of extracellular metabolites，and good disease prevention and growth promotion effect，having great potential for developing biocontrol agent exclusively for potato．