马铃薯干腐病拮抗菌的鉴定及生物学特性

在马铃薯干腐病发生严重地区,从健康植株根际土壤中筛选获得1株拮抗菌BAM-2,通过形态特征、生理生化特性及16S rDNA 序列分析鉴定该菌株为甲基营养型芽孢杆菌(Bacillus methylotrophicus)。BAM-2对茄链格孢菌(Alternaria solani)、灰葡萄孢菌(Botrytis cinerea)、接骨木镰孢菌(Fusarium sambucinum)、立枯丝核菌(Rhizoctonia solani)及梨黑斑病菌(Alternaria alternata)的抑菌率均达80% 以上,其胞外抗菌物质经60～100 ℃处理30 min、胰蛋白酶及胃蛋白酶处理、紫外线照射及反复冻融处理,抑菌率均维持在95%以上;pH值在2～11之间抑菌率保持在83%以上。说明BAM-2的胞外抗菌物质对植物真菌病害抑菌谱广,在热、酸碱、蛋白酶、紫外线照射及反复冻融方面具有较强的稳定性,在研发为抗植物真菌病害的生物农药方面具有较大的潜力。

Identification and Biological Characteristics of Antagonistic Bacteria Against Potato Dry Rot

Taking a strain of antagonistic BAM-2 obtained from the rhizosphere of healthy growing potatoes，in areas where potato dry rot occurred severely，this paper identified this bacterial strain as Bacillus methylotrophicus by morphological，physiological and biochemical characteristics analysis and 16S rDNA sequence．The antibacterial rates of BAM-2 against Alternaria solani，Botrytis cinerea，Fusarium sambucinum，Rhizoctonia solani and Alternaria alternata were over 80%．After being treated at 60-100 ℃ for 30 min，with trypsin and pepsin treatment，ultraviolet irradiation and repeated freeze-thaw treatment，the extracellular antibacterial substance and its antibacterial rate were all remained above 95%．When the pH value was between 2 and 11，its antibacterial rate was still remained above 83%，indicating that the extracellular antibacterial substance of BAM-2 had broad antibacterial spectrum against plant fungal diseases and stronger stability in the aspects of heat，acid-base，protease，ultraviolet irradiation and repeated freeze-thaw cycles．It can be seen that strain BAM-2 has greater potential in R&D of biological pesticide against plant fungal diseases．