Gundersen D E, Lee I M, Rehner S A, Davis R E, Kingsbury D T
Molecular Plant Pathology Laboratory, Agriculture Research Service, U.S. Department of Agriculture, Beltsville, Maryland 20705.
J Bacteriol. 1994 Sep;176(17):5244-54. doi: 10.1128/jb.176.17.5244-5254.1994.
A global phylogenetic analysis using parsimony of 16S rRNA gene sequences from 46 mollicutes, 19 mycoplasmalike organisms (MLOs) (new trivial name, phytoplasmas), and several related bacteria placed the MLOs definitively among the members of the class Mollicutes and revealed that MLOs form a large discrete monophyletic clade, paraphyletic to the Acholeplasma species, within the Anaeroplasma clade. Within the MLO clade resolved in the global mollicutes phylogeny and a comprehensive MLO phylogeny derived by parsimony analyses of 16S rRNA gene sequences from 30 diverse MLOs representative of nearly all known distinct MLO groups, five major phylogenetic groups with a total of 11 distinct subclades (monophyletic groups or taxa) could be recognized. These MLO subclades (roman numerals) and designated type strains were as follows: i, Maryland aster yellows AY1; ii, apple proliferation AP-A; iii, peanut witches'-broom PnWB; iv, Canada peach X CX; v, rice yellow dwarf RYD; vi, pigeon pea witches'-broom PPWB; vii, palm lethal yellowing LY; viii, ash yellows AshY; ix, clover proliferation CP; x, elm yellows EY; and xi, loofah witches'-broom LfWB. The designations of subclades and their phylogenetic positions within the MLO clade were supported by a congruent phylogeny derived by parsimony analyses of ribosomal protein L22 gene sequences from most representative MLOs. On the basis of the phylogenies inferred in the present study, we propose that MLOs should be represented taxonomically at the minimal level of genus and that each phylogenetically distinct MLO subclade identified should represent at least a distinct species under this new genus.
利用简约法对46种柔膜菌纲微生物、19种类支原体生物（新俗名，植原体）以及几种相关细菌的16S rRNA基因序列进行的全球系统发育分析，明确将类支原体生物置于柔膜菌纲成员之中，并揭示类支原体生物形成了一个大型离散单系分支，在厌氧支原体分支内，相对于无胆甾原体属物种为并系分支。在全球柔膜菌纲系统发育中解析出的类支原体生物分支以及通过对来自代表几乎所有已知不同类支原体生物组的30种不同类支原体生物的16S rRNA基因序列进行简约分析得出的综合类支原体生物系统发育中，可以识别出五个主要系统发育组，共有11个不同的亚分支（单系组或分类单元）。这些类支原体生物亚分支（罗马数字）及其指定的模式菌株如下：i，马里兰紫菀黄化病AY1；ii，苹果增殖病AP - A；iii，花生丛枝病PnWB；iv，加拿大桃X CX；v，水稻黄矮病RYD；vi，木豆丛枝病PPWB；vii，棕榈致死黄化病LY；viii，白蜡树黄化病AshY；ix，三叶草增殖病CP；x，榆黄化病EY；xi，丝瓜丛枝病LfWB。亚分支的命名及其在类支原体生物分支内的系统发育位置得到了通过对大多数代表性类支原体生物的核糖体蛋白L22基因序列进行简约分析得出的一致系统发育的支持。基于本研究推断的系统发育，我们建议类支原体生物在分类学上应至少在属的水平上进行表示，并且在此新属之下，每个识别出的系统发育上不同的类支原体生物亚分支应至少代表一个不同的物种。
