马铃薯环腐病生防菌株P1的鉴定、防病效果及促生作用研究

Identification,disease-preventing role and growth-promoting effect of biocontrol strain P1 to potato bacteria ring rot

在马铃薯环腐病区采集健康的马铃薯Solanum tuberosum块茎,从中分离到1株对马铃薯环腐病菌Clavibacter michiganense subsp.sepedonicum具有强拮抗作用的内生细菌P1。经形态观察、生理生化鉴定,菌株P1归属为Bacillussp.,进一步经16SrDNA序列对比分析,确定为巨大芽孢杆菌B.megatherium。经证明,P1菌株的培养液抗菌粗提物属于蛋白类,该抗菌蛋白对紫外光不敏感,pH为7.0时抑菌活性最强,温度高于80℃时抑菌活性明显下降。温室试验表明,P1菌株能显著提高马铃薯植株的株高、茎粗、产量及大薯率,其对马铃薯环腐病防效达53.4%。

The endophytic bacteria strain P1 was isolated from healthy potato tubers collected in potato bacterial ring rot field. Antagonistic tests showed that P1 strongly restricted growth of the pathogenic bacterium, Clavibacter michiganense subsp. sepedonicum. Strain P1 was preliminarily identified as Bacillus sp. based on the morphological, physiological and biochemical characteristics and then as B.megatherium by further contrast analysis of 16S rDNA sequence. The antibacterial substances extracted from P1 cultures were proven as crude protein, which were not sensitive to UV and showed the strongest activity at pH 7.0.The inhibitory activity of the crude protein decreased significantly when the temperature was higher than 80℃. Greenhouse tests indicated that strain P1 had a significant role in biocontrol against potato bacterial ring rot with the efficiency of 53.4% and in the promotion of seedling height, stem thickness, potato weight and the rate of commodity tubers.