沙棘和沙枣根瘤中固氮放线菌物种多样性研究

目的]以沙棘和沙枣根瘤为研究对象,深入研究固氮放线菌物种的多样性。方法]以通常用于分离弗兰克氏菌属（Frankia）固氮放线菌的无氮BAP、S、JA、ISP4、CB-CcI3、DPM和FTW等为固体和液体培养基,对采集自内蒙古通辽和赤峰的沙棘（Hippophae）和沙枣（elaeagnus）植物根瘤进行放线菌的分离纯化,并依据16S rDNA序列测定结果对分离物进行系统发育分析。结果]分离得到的8株放线菌分属于小单孢菌属（Micromonospora）、链霉菌属（Streptomyces）、野野村菌属（Nonomuraea）和假诺卡菌属（Pseudonocardia）,所有根瘤样品中均未分离到弗兰克氏菌属菌株;采用弗兰克氏菌属16S-23S rDNA间隔区序列的特异性引物对所采集的沙棘和沙枣植物根瘤总DNA进行PCR扩增,未出现特异性的16S-23S rDNA间隔区序列条带。结论]非豆科植物根瘤内固氮放线菌具有物种多样性,为今后固氮放线菌物种多样性研究提供借鉴。

Study on Species Diversity of Nitrogen-fixing Actinomycetes in Hippophae and Elaeagnus Root Nodules

Objective] With Hippophae and Elaeagnus root nodules as research objects, the species diversity of nitrogen-fixing actinomycetes was studied. Method] Solid and liquid medium of the nitrogen-free BAP, S, JA, ISP4, CB-CcI3, DPM, FTW were used to isolate and purify root nodules of Elaeagnus and Hippophae collected from Tongliao and Chifeng in Inner Mongolia. According to determination results of 16S rDNA sequence, a phylogenetic analysis was carried out. Result] The results indicated that all of the 8 strains belong to Micromonospora, Streptomyces, Nonomuraea and Pseudonocardia respectively. However, none of strains isolated from above-mentioned nodules belong to Frankia. 16S-23S intergenic sequences in the total DNA of Elaeagnus and Hippophae nodules were amplified using specific primers of genus Frankia, but there was none of specific band. Conclusion] Nitrogen-fixing actinomycetes in non-legumes root nodules have a character of species diversity, which will provide a basis for studying species diversity of nitrogen-fixing actinomycetes.