Jeong S C, Ritchie N J, Myrold D D
Plant Physiology Program, Oregon State University, Corvallis, Oregon, 97331, USA.
Mol Phylogenet Evol. 1999 Dec;13(3):493-503. doi: 10.1006/mpev.1999.0692.
Molecular phylogenetic trees were reconstructed from nucleotide sequences of nifH and 16S rDNA for Frankia and of rbcL for actinorhizal plants. Comparison of Frankia phylogenetic trees reconstructed using nifH and 16S rDNA sequences indicated that subgroupings of both trees correspond with each other in terms of plant origins of Frankia strains. The results suggested that 16S rDNAs can be utilized for coevolution analysis of actinorhizal symbioses. Frankia and plant phylogenetic trees reconstructed using 16S rDNA and rbcL sequences were compared. The comparison by tree matching and likelihood ratio tests indicated that although branching orders of both trees do not strictly correspond with each other, subgroupings of Frankia and their host plants correspond with each other in terms of symbiotic partnership. Estimated divergence times among Frankia and plant clades indicated that Frankia clades diverged more recently than plant clades. Taken together, actinorhizal symbioses originated more than three times after the four plant clades diverged.
利用弗兰克氏菌（Frankia）的固氮酶基因（nifH）和16S核糖体DNA（rDNA）的核苷酸序列以及放线菌根植物的核酮糖-1,5-二磷酸羧化酶大亚基基因（rbcL）重建了分子系统发育树。对使用nifH和16S rDNA序列重建的弗兰克氏菌系统发育树进行比较，结果表明，就弗兰克氏菌菌株的植物来源而言，两棵树的亚分组相互对应。结果表明，16S rDNAs可用于放线菌根共生的协同进化分析。比较了使用16S rDNA和rbcL序列重建的弗兰克氏菌和植物系统发育树。通过树匹配和似然比检验进行的比较表明，尽管两棵树的分支顺序并不严格对应，但就共生伙伴关系而言，弗兰克氏菌及其寄主植物的亚分组相互对应。弗兰克氏菌和植物分支之间的估计分歧时间表明，弗兰克氏菌分支的分歧时间比植物分支更近。综上所述，在四个植物分支分化后，放线菌根共生起源超过三次。
