Sramkó Gábor, Attila Molnár V, Hawkins Julie A, Bateman Richard M
MTA-ELTE-MTM Ecology Research Group, Pázmány P. sétány 1/C, Budapest, 1117, Hungary Department of Botany, University of Debrecen, Egyetem ter 1., Debrecen, 4032, Hungary
Department of Botany, University of Debrecen, Egyetem ter 1., Debrecen, 4032, Hungary.
Ann Bot. 2014 Dec;114(8):1609-26. doi: 10.1093/aob/mcu179. Epub 2014 Oct 7.
Lizard orchids of the genus Himantoglossum include many of Eurasia's most spectacular orchids, producing substantial spikes of showy flowers. However, until recently the genus had received only limited, and entirely traditional, systematic study. The aim of the current work was to provide a more robust molecular phylogeny in order to better understand the evolutionary relationships among species of particular conservation concern.
All putative species of Himantoglossum s.l. were sampled across its geographical range. A large subsample of the 153 populations studied contributed to an initial survey of nuclear ribosomal internal transcribed spacer (nrITS) ribotypes. Smaller subsets were then sequenced for four plastid regions and the first intron of the low-copy-number nuclear gene LEAFY. Rooted using Steveniella as outgroup, phylogenetic trees were generated using parsimony and Bayesian methods from each of the three datasets, supplemented with a ribotype network.
The resulting trees collectively determined the order of branching of the early divergent taxa as Himantoglossum comperianum > H. robertianum group > H. formosum, events that also involved significant morphological divergence. Relaxed molecular clock dating suggested that these divergences preceded the Pleistocene glaciations (the origin of the H. robertianum group may have coincided with the Messinian salinity crisis) and occurred in Asia Minor and/or the Caucasus. Among more controversial taxa of the H. hircinum-jankae clade, which are only subtly morphologically divergent, topological resolution was poorer and topological incongruence between datasets was consequently greater.
Plastid sequence divergence is broadly consistent with prior, morphologically circumscribed taxa and indicates a division between H. hircinum-adriaticum to the west of the Carpathians and H. jankae-caprinum (plus local endemics) to the east, a distinction also suggested by nrITS ribotypes. LEAFY phylogenies are less congruent with prior taxonomic arrangements and include one likely example of paralogy. Himantoglossum metlesicsianum fully merits its IUCN Endangered status. Potentially significant genetic variation was detected within Steveniella satyrioides, H. robertianum and H. hircinum. However, confident circumscription of the more derived species of Himantoglossum s.s., including local endemics of hybrid origin, must await future morphometric and population-genetic analyses.
舌唇兰属的蜥蜴兰包括许多欧亚大陆最引人注目的兰花，能长出大量艳丽花朵的花穗。然而，直到最近，该属仅得到有限的、完全传统的系统研究。当前这项工作的目的是提供一个更可靠的分子系统发育树，以便更好地理解具有特殊保护意义的物种之间的进化关系。
对广义舌唇兰属所有假定的物种在其地理分布范围内进行采样。在研究的153个种群中抽取的一个大的子样本用于初步调查核糖体核糖核酸内转录间隔区（nrITS）核糖型。然后对较小的子集进行四个质体区域和低拷贝数核基因LEAFY的第一个内含子的测序。以史蒂文氏兰属作为外类群进行定根，使用简约法和贝叶斯法从三个数据集中的每一个生成系统发育树，并辅以核糖型网络。
所得的树共同确定了早期分化类群的分支顺序为康氏舌唇兰>罗伯特舌唇兰组>台湾舌唇兰，这些事件也涉及显著的形态差异。宽松分子钟定年表明，这些分化发生在更新世冰川作用之前（罗伯特舌唇兰组的起源可能与墨西拿盐度危机同时发生），且发生在小亚细亚和/或高加索地区。在羊耳蒜 - 扬卡舌唇兰分支中更具争议的类群中，它们在形态上仅有细微差异，拓扑分辨率较差，因此数据集之间的拓扑不一致性更大。
质体序列差异大致与先前根据形态界定的类群一致，表明喀尔巴阡山脉以西的羊耳蒜 - 亚得里亚舌唇兰与以东的扬卡舌唇兰 - 山羊舌唇兰（加上当地特有种）之间存在区分，nrITS核糖型也表明了这一区别。LEAFY系统发育树与先前的分类安排不太一致，并且包括一个可能的旁系同源性例子。梅氏舌唇兰完全符合其在世界自然保护联盟濒危物种红色名录中的濒危等级。在史蒂文氏兰、罗伯特舌唇兰和羊耳蒜中检测到了潜在的显著遗传变异。然而，要可靠地界定狭义舌唇兰属中更多衍生的物种，包括杂交起源的当地特有种，必须等待未来的形态测量和种群遗传学分析。
