香蕉枯萎病拮抗菌的筛选鉴定及其防病效果测定

Screening,identification and control efficiency of antagonistic bacteria for banana fusarium wilt

  • 摘要: 【目的】从不同作物的根围土壤中分离筛选香蕉枯萎病菌拮抗菌,对拮抗菌进行鉴定并测定其防病效果,以期为香蕉枯萎病的生物防治提供新的菌种资源。【方法】以尖孢镰刀菌古巴专化型4号生理小种(Fusarium oxysporum f.sp.cubense 4,Foc4) Foc 1402菌株为对象,采用稀释涂布法对不同作物根围土壤中的细菌进行分离,并使用平板对峙法和牛津杯法筛选其中的香蕉枯萎病拮抗菌。根据细菌菌落形态、生理生化特征结合16S rDNA序列分析对拮抗菌进行分类鉴定。使用威廉斯B6香蕉杯苗测定拮抗菌对香蕉枯萎病的盆栽防治效果。【结果】从不同作物根围分离获得345株细菌,从中筛选获得7株对香蕉枯萎病菌具有较强拮抗活性的菌株,抑菌率最高可达72.65%。依据形态学观察、生理生化反应和16S rDNA序列分析结果,菌株Ba02、Ba310、Ba48、Ba62和Ba63被鉴定为解淀粉芽孢杆菌(Bacillus amyloliquefaciens),菌株Bc11被鉴定为洋葱伯克霍尔德氏菌(Burkholderia cepacia),菌株Pt05被鉴定为土地类芽孢杆菌(Paenibacillus terrae)。盆栽试验结果显示,7株拮抗细菌对香蕉枯萎病的防治效果在20.00%~68.89%,其中以菌株Bc11的防治效果最好,为68.89%。【结论】从不同作物的根围土壤中筛选获得7株对Foc具有较强拮抗活性的细菌,其中,土地类芽孢杆菌为香蕉枯萎病生防菌家族的新成员。筛选获得的不同种类拮抗菌可作为研制香蕉枯萎病生防菌剂的候选菌株资源,在后续开发抗病复合菌剂方面具有良好的应用前景。

     

    Abstract: 【Objective】This study was conducted to isolate and screen the antagonists against banana fusarium wilt from the rhizosphere soil of different crops, and then identify them and evaluate their control effects, to provide new bacteria resources forthe biological control of banana fusarium wilt.【Method】 Targeting the Foc 1402 strain of Fusarium oxysporum f. sp. cubense 4, Foc 4,the bacteria in rhizosphere soil of different crops were isolated by gradient dilution coating method,and the antagonistic bacteria of banana fusarium wilt were screened by the plate confrontation method and the Oxford cup assay. The isolates were identified by morphological,physiological,biochemical features and the analysis of 16S rDNA sequences. And the control effects of antagonistic bacteria on banana fusarium wilt were evaluated through pot experiments using banana seedlings of Williams B6.【Result】 A total of 345 bacterial strains were isolated from rhizosphere soil of different crops. Of these,7 strains with strong antagonistic activity against banana fusarium wilt were screened, and the highest inhibition rate was 72.65%. According to the results of morphological,physiological and biochemical characteristics and 16s rDNA sequence analysis,strains Ba02,Ba310,Ba48,Ba62 and Ba63 were identified as Bacillus amyloliquefaciens,the strain Bc11 was identified as Burkholderia cepacia,and the strain Pt05 was identified as Paenibacillus terrae. Pot experiments revealed that the control effects of 7 antagonistic bacteria on banana fusarium wilt were 20.00%-68.89%,and the strain Bc11 was the most effective against banana fusarium wilt(68.89%) .【Conclusion】In this study,7 biocontrol bacteria withstrong control effects on banana fusarium wilt were screened from the rhizosphere soil of different crops. Among them,P. terrae is a new member of the biocontrol bacteria family of banana fusarium wilt. At the same time,the different kinds of antagonistic bacteria obtained can serve as candidate strain resources for the development of biocontrol agents against banana fusarium wilt,and have good application prospects in the subsequent development of disease resistant composite bacterial agents.

     

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