Genetic diversity which was determined by the analysis of 16s rdna - rflp and 16s rdna - sequencing were carried out on frankia strains isolated from the root nodules of different actinorhizal plants , including myrica , casuarina , alnus and coriaria . the main results of the research project were as follows 本研究课题对来自杨梅( myrica ) 、木麻黄( casuarina ) 、桤木( alnus )和马桑( coriaria )的13株frankia菌纯培养的16srrna基因进行了pcr - rflp分析和部分菌株的序列测定，初步探讨了弗兰克氏菌的遗传多样性和系统发育地位。
The method was modified by adding suitable insoluble pvp and higher concentration of p - mercapto ethanol in the extract solution . using the modified method , high quality genomic dna prepared from ginkgo , grape and myrica are colorless and are susceptible to digestion with the restriction endonucleases and can be used as template for pcr 我们将ctab法稍做改良：研磨样品时加入适量的不溶性pvp ，提高-巯基乙醇在提取液中的比例，从而提取到了无色、可酶解、可作pcr模板的高质量的银杏基因组dna 。
In addition , the evident crossing - infection happened in the strains came from myrica , casuarina also could be found in the sequencial analysis . all these results we obtained from the sequencing and rflp analysis were partly accorded with what baker brought forward in 1987 ( the four host specific group , hsg ) . however , they also indicated the limit of this hsg 5株供试菌株与其它已发表菌株的全序列比较结果可将所有菌株大致划分为4个簇，杨梅菌株fmr61 、木麻黄菌株fcg07和木麻黄菌株fce42具有较高相似性与桤木菌株聚为第簇；而杨梅菌株fmr16和2215与来自胡颓子科和沙棘的菌株聚在一起归为第簇。
