鼓槌石斛内生细菌分离、 鉴定及功能分析

为微生物农药和肥料生产提供菌种资源,用组织分离法从鼓槌石斛健康组织分离内生细菌,用对峙法和抑菌圈法筛选拮抗菌株;以平板法筛选解磷、解钾和固氮菌株;以田间试验检验固氮菌株的增产效果;用PCR扩增功能菌株的16S rDNA,结合菌株的菌体、菌落形态特征和部分生理生化特征,确定功能菌株分类地位。结果表明,从鼓槌石斛组织共分离到33株内生细菌,数量和种类为根〉茎〉叶;其中GB7属解淀粉芽孢杆菌（Bacillus amyloliquefaciens）,GB16属链霉菌（Streptomyces sp.）,GB8、GB9、GB21属芽孢杆菌（Bacillus spp.）,均有病害生防功能;GB2属不动杆菌（Acinetobacter calcoaceticus）,GB20属肠杆菌（Enterobacter sp.）,具解磷功能;菌株GB1属产酸克雷伯氏菌（Klebsiellaoxytoca）,具固氮功能。

Isolation, Identification and Functional Analyses of Endophytic Bacteria from Dendrobium chrysotoxum

To provide microbial fungicide and biofertilizer production with bacterial sources, endophytic bacteria were isolated from Dendrobium chrysotoxum by tissue culture, antagonistic bacteria were screened by dual culture and inhibitory zone, phosphate- and potassium-solubilizing and nitrogen-fixing bacteria were selected by medium plate, and yield increase by nitrogen-fixing strain was confirmed by field experiment. The bacteria were identified based on their 16S rDNA sequence by PCR amplification, morphology of their cells and colonies, and partial physiological and biochemistry traits. The results showed that 33 strains were obtained with the number order, root > stem > leaf. Among them, GB7 belonged to Bacillus amyloliquefaciens, GB16 to Streptomyces sp., GB8, GB9 and GB21 to Bacillus spp. with disease control effect. GB2 was identified as Acinetobacter calcoaceticus, and GB20 as Enterobacter sp. with phosphate-solubilizing effect, GB1 was classified into Klebsiella oxytoca with nitrogen-fixing effect.