苹果树内生细菌G23的鉴定及其抑菌活性的研究

从苹果树木质部中分离到1株内生拮抗细菌G23，为明确其分类地位及抑菌活性，采用形态学、生理生化测定及16S rDNA序列分析对其分类地位进行鉴定，并对其发酵液进行过滤及高温处理，分析其抗菌物质类型。研究结果表明：该菌株为1株枯草芽孢杆菌（Bacillus subtilis）。该菌株发酵滤液对所测8种病原真菌的抑制率在63.4%~87.5%之间，发酵液经高温处理后活性降低，对8种病原菌的抑制率在57.4%~79.6%，因此推测该菌株可能分泌多种拮抗物质，包括对热不敏感的抗生素类，也包括对高温敏感的肽类及蛋白酶类。

Identification of Endophytic Bacterium Strain G23 and the Research of Its Inhibition to Some Phytopathogens

One endophytic bacteria G23 strain which could significantly inhibit some phytopath-ogenic fungi was isolated from xylem of apple. In order to clarify the taxonomic status and the antifungal activity, the morphology, physiological, biochemical characteristics and 16S rDNA sequence analysis were used to identify the taxonomic status. The fermentation liquid passed the filter and high-temperature process, and the types of antimicrobial substances were analyzed. The results showed that this strain was identified as Bacillus subtilis. The inhibition rate of its filtration ranged from 63.4% to 87.5% on 8 kinds of pathogens, but it decreased and inhibitory rate ranged from 57.4% to 79.6% after the treatment of high temperature. Thus, it confirmed that this strain could secrete various antagonistic substances included temperature-insensitive antibiotic as well as temperature-sensitive peptides and protease.