利用棉花不同生育期的拮抗内生菌协同控制棉黄萎病研究

[目的]探讨棉花不同生育期的生防菌组合防治棉花黄萎病效果,以期为植物其他土传病害的生物防治提供新的策略。[方法]分别筛选棉花苗期、现蕾期和结铃期的高抗黄萎病内生菌,测定其16S rDNA序列并进行比对分析,鉴定筛选出的3个菌株,探讨了该3个菌株在棉株内的定殖规律,并进行室内和田间防效测定。[结果]根据16S rDNA序列同源性,3个菌株分别鉴定为Paenibacillus poly-myxa YUPP-8、Paenibacillus xylanilyticus YUPP-1和Bacillus subtilis YUPP-2。定殖评价试验结果显示3个菌株均能顺利定殖于棉花体内,施用剂量与其在棉株内的定殖量具有正效应关系,在棉花苗期定殖量最高的菌株为YUPP-8,在棉花现蕾期定殖量最高的菌株为YUPP-1,在棉花结铃期定殖量最高的菌株为YUPP-2。室内盆栽抗病结果显示3个菌株联合处理的棉株在开花期未发病,单菌处理的棉株在苗期发病率分别为:6.7%(YUPP-8)、6.7%(YUPP-1)和13.3%(YUPP-2);而此时对照的发病率高达80%。2010～2011年2年的小区防治试验结果表明3菌联合灌根处理效果优于单菌株施用效果,其中2,010年3菌联合灌根处理区棉花结铃期黄萎病发病率和病指分别为9.4%和6.5,对照分别为47.5%和32.82,011年的结果趋势与2010年类似,但病害严重度更高一些。上述结果表明联合棉花各生育期的内生菌来防治棉花黄萎病具有巨大的应用潜力。[结论]该研究结果初步克服了目前生防菌开发中的缺陷,对其他植物土传病害的防治具有借鉴意义。

Antagonistic Endophytic Bacteria Isolated from Different Growth Stages of Cotton for the Control of Cotton Verticillium Wilt

[Objective] This study aimed to investigate the combined control effects of endophytic bacteria at different growth stages against Verticillium dahliae and provide a new strategy for the biocontrol of other soil-borne diseases.[Method] Endophytic bacteria with high resistance against Verticillium dahliae were isolated from seedling,squaring and boll-setting cotton vascular,respectively.Their 16S rDNA sequences were detected for comparative analysis.Three biocontrol strains were selected and identified,whose colonization roles in cotton plants were explored.The control efficiency was determined with indoor and field experiments.[Result] According to the 16S rDNA sequence homology,the three strains were identified as Paenibacillus polymyxa YUPP-8,Paenibacillus xylanilyticus YUPP-1 and Bacillus subtilis YUPP-2,respectively.Results of colonization assessment showed that three strains all could be successfully colonized in cotton vascular.But application amount had a positive effect on the number of colonized biocontrol bacteria in cotton.Strain YUPP-8 had the largest number of colonized biocontrol bacteria in seedling period.Strain YUPP-1 had the largest number of colonized biocontrol bacteria in squaring period,and strain YUPP-2 had the largest number of colonized biocontrol bacteria in boll-setting period.Indoor pot experiment showed that cotton plants in combined biocontrol bacteria treatment group were not infected in flowing period,while Verticillium dahliae of cotton treated with single strain in seedling period were 6.7%(YUPP-8),6.7%(YUPP-1) and 13.3%(YUPP-2);however,Verticillium dahliae of the control reached 80%.Field experiment conducted during 2010-2011 showed that the combined application of three strains had better effect than separate application;specifically,Verticillium dahliae morbidity rate and disease index of cotton in boll-setting period with combined application of three strains in 2020 were 9.4% and 6.5,respectively,while those in control group were 47.5% and 32.8;results in 2011 were similar to 2010,with higher disease severity.These results indicate that combined application of endophytic bacteria at different growth stages has great application potential in control of cotton Verticillium dahliae.[Conclusion] This study preliminarily overcome the defects in the application of biocontrol bacteria and provided reference for the prevention and treatment of other soil-borne diseases.