水生拉恩氏菌ZF7分离鉴定及其促生防病效果研究

 从樱花根际土壤中分离到一株对大白菜黑腐病菌具有强拮抗作用的细菌ZF7。根据生物学特征、16S rDNA 序列分析、Biolog及生理生化分析,菌株ZF7被鉴定为水生拉恩氏菌Rahnella aquatilis。利用平板对峙法和双层培养法,证明菌株ZF7具有较广的抑菌谱,对5种病原真菌和5种病原细菌具有明显拮抗效果。而且,该菌能在大白菜根际土壤以及白菜根部稳定定殖。采用盆栽试验对菌株ZF7进行促生防病效果测定,结果表明该菌对大白菜具有显著的促生效果。灌根菌量为20 mL/株时,菌株ZF7对大白菜株高和根长的促生率分别达56.47%、54.74%,对地上部重量及根重的促生率分别达233.84%和164.71%。同时,菌株ZF7对大白菜黑腐病具有良好的防治效果,防效可达88.80%,高出中生菌素的防治效果26.76%。综上分析,菌株ZF7生防性状优良,具有一定的田间应用开发潜力。

Isolation and identification of Rahnella aquatilis ZF7 and its effect on growth promotion and disease suppression

Bacterial strain ZF7 was isolated from the rhizosphere soil of cherry tree (Cerasus sp.) and exhibited significant inhibitory activity against Xanthomonas campestris pv. campestris. Based on biological characteristics, 16S rDNA sequence analysis, Biolog analysis as well as physiological and biochemical characteristics, the strain ZF7 was identified as Rahnella aquatilis. The antimicrobial test using plate confrontation method and double-layer culture method showed a strong inhibition activity of strain ZF7 against a broad spectrum of phytopathogens, including five pathogenic fungi and five pathogenic bacteria. Moreover, strain ZF7 successfully colonized and formed a stable population in roots and rhizosphere of Chinese cabbage. The plant growth-promoting effect and disease suppressive activity of ZF7 were evaluated in pot under greenhouse conditions. Drenching treatment with strain ZF7 (20 mL per plant) increased plant height and root length by 56.47% and 54.74%, respectively, and increased aboveground part and root weight by 233.84% and 164.71%, respectively. Meanwhile, strain ZF7 inoculation significantly suppressed Chinese cabbage black rot caused by X. campestris pv. campestris with the efficacy of 88.80%, which is 26.76% higher than that treated by Zhongshengmycin. In summary, R. aquatilis ZF7 exhibits multiple properties beneficial to the plants and is expected to be applied in the field as a potential biopesticide.