Faculty of Science, Charles University, Benátská 2, 128 00, Prague, Czech Republic.
Dipartimento di Scienze della Vita e dell'Ambiente, Università Politecnica delle Marche, Via Brecce Bianche, 60131, Ancona, Italy.
J Phycol. 2019 Feb;55(1):224-235. doi: 10.1111/jpy.12817. Epub 2018 Dec 18.
Mats of the green alga Trentepohlia, a genus widely distributed in the tropics as well as temperate regions, have always been perceived as homogeneous (i.e., formed by only one species). As such, their general nature and specific feature play a supportive role in the species delimitation. However, the presence of morphologically dissimilar thalli was observed under the light microscope and when cultivating a piece of a single mat. To address this, we performed DNA cloning of the rbcL gene on mat fragments of T. abietina, T. annulata, T. jolithus and T. umbrina sampled in Europe to reveal if they are composed of one or more species. We revealed that more Trentepohlia haplotypes may coexist in a single mat. In consideration of this, we conclude that the use of material isolated in unialgal culture will be almost mandatory for a taxonomic reassessment of this complicated genus. Another direct implication of this problem is that herbarium specimens consisting of field-collected material should not be used for direct sequencing. We further hypothesize the reasons why multiple haplotypes of Trentepohlia occur more frequently in the tuft-like mats. Possibly, fragments and/or cells of other microalgae, including other species of Trentepohlia, might be retained in such mats more easily than in the crustose trentepohlialean mats.
绿藻丛枝藻属（Trentepohlia）的藻丛，广泛分布于热带和温带地区，一直被认为是同质的（即仅由一个物种组成）。因此，它们的一般性质和特征在物种划分中起着支持作用。然而，在显微镜下观察和培养单个藻丛时，会发现形态不同的藻丝体。为了解决这个问题，我们对取自欧洲的单株藻丛碎片进行了 rbcL 基因的 DNA 克隆，以揭示它们是否由一个或多个物种组成。我们发现，在单个藻丛中可能共存着更多的丛枝藻单倍型。考虑到这一点，我们得出结论，对于这个复杂的属进行分类学重新评估，使用分离自单藻培养的材料几乎是强制性的。这个问题的另一个直接影响是，由野外采集材料组成的标本不应该直接用于测序。我们进一步假设丛枝藻多个单倍型更频繁地出现在束状藻丛中的原因。可能是其他微藻的片段和/或细胞，包括其他丛枝藻物种，更容易在这种藻丛中保留下来，而不是在壳状丛枝藻状藻丛中保留下来。
