（1College of Life Science，Hebei Normal University，Shijiazhuang 050024，Hebei，China；2Institute of Biology，Hebei
Academy of Science，Shijiazhuang 050081，Hebei，China；3College of Biological Science and Engineering，Hebei University
of Science and Technology，Shijiazhuang 050018，Hebei，China）
Abstract：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．
