Bloom R A, Mullin B C, Tate R L
Department of Soils and Crops, Rutgers University, New Brunswick, New Jersey 08903-0231.
Appl Environ Microbiol. 1989 Sep;55(9):2155-60. doi: 10.1128/aem.55.9.2155-2160.1989.
Sixteen Frankia strains were isolated from Myrica pennsylvanica (bayberry) root nodules collected at diverse sites in New Jersey. Restriction pattern analysis of total genomic DNA was used to group the isolates into gel groups, and the genetic relatedness among the isolates was evaluated by DNA-DNA solution hybridization studies. Restriction pattern analysis provided a distinctive reproducible fingerprint for each isolate. Isolates fell into nine separate groups (strain types). More than one strain type was isolated from most sites. Isolates from two different gel groups were found in 3 of 10 nodules examined. Of the 16 isolates, 10 contained extrachromosomal DNA. Six different extrachromosomal DNA banding patterns were found. Genomically similar isolates carried related, but different, banding patterns. DNA hybridization studies indicated that isolates from a single plant species can be minimally related as determined by total genome homology. Homology ranged from 12 to 99%. Highly divergent strains were isolated from the same plant and found to cohabit the same nodule. Thus, this study demonstrated that Frankia strains which infect the same host plant are not only phenotypically different but also genetically diverse.
从新泽西不同地点采集的宾夕法尼亚杨梅（杨梅）根瘤中分离出16株弗兰克氏菌菌株。利用总基因组DNA的限制性图谱分析将分离株归为凝胶组，并通过DNA-DNA溶液杂交研究评估分离株之间的遗传相关性。限制性图谱分析为每个分离株提供了独特的可重复指纹。分离株分为九个不同的组（菌株类型）。大多数地点分离出不止一种菌株类型。在10个检测的根瘤中有3个发现了来自两个不同凝胶组的分离株。16个分离株中，10个含有染色体外DNA。发现了六种不同的染色体外DNA条带模式。基因组相似的分离株携带相关但不同的条带模式。DNA杂交研究表明，根据全基因组同源性确定，来自单一植物物种的分离株之间的相关性可能极低。同源性范围为12%至99%。从同一植物中分离出高度不同的菌株，并发现它们共居于同一个根瘤中。因此，本研究表明，感染同一宿主植物的弗兰克氏菌菌株不仅在表型上不同，而且在遗传上也具有多样性。
