Functional diversity in cryptic species of Chaetoceros socialis Lauder (Bacillariophyceae)
Functional diversity in cryptic species of Chaetoceros socialis Lauder (Bacillariophyceae)
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DOI：
10.1093/plankt/fbs004
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发表时间：
2012-05-01
影响因子：
2.1
通讯作者：
Landfald, Bjarne
中科院分区：
文献类型：
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作者：
Degerlund, Maria;Huseby, Siv;Landfald, Bjarne
海洋浮游硅藻Chaetoceros socialis Lauder的世界性分布通常被解释为广泛的生态可塑性。然而，隐藏的多样性最近被观察到在这个分类群和这种遗传多样性可能会延伸到异域种群之间的表型差异。C.将从东北大西洋/北极和第勒尼安海沃茨分离的socialis在2.5、8和13 ℃下培养，并分析形态、系统发育（LSU rRNA基因）和生理（生长速率、光合产量）特征。分子分析表明，南方和北方菌株之间存在明确的分歧。两组之间的孢子形态也观察到明显的差异，尽管它们的营养形态相似。生理数据证明了北方和南方菌株之间的功能分区。在较低温度下，北方菌株的生长速率显著高于南方菌株，在13 ℃下，反之亦然。还观察到各组之间的光合产量的差异。这些结果揭示了在几个表型性状的异域物种形成的表达，提供了一个功能层面的神秘，或更确切地说，伪神秘，在C。socialis。我们相信，这样一个综合的方法是有用的强大的分类和功能界定假定世界性微生物。
The cosmopolitan distribution of the marine planktonic diatom Chaetoceros socialis Lauder is generally interpreted as a case of wide ecological plasticity. However, cryptic diversity has recently been observed within this taxon and this genetic diversity could extend to phenotypic differences between allopatric populations. Monoclonal strains of C. socialis isolated from NE Atlantic/Arctic and Tyrrhenian Sea waters were cultivated at 2.5, 8 and 13C, and analysed for morphological, phylogenetic (LSU rRNA gene) and physiological (growth rate, photosynthetic yield) traits. The molecular analysis indicated an unequivocal divergence between the southern and the northern strains. Clear differences in spore morphology between the two groups were also observed, despite their morphological similarity in vegetative form. The physiological data demonstrated a functional partition between the northern and southern strains. The northern strains showed significantly higher growth rates than the southern ones at the lower temperatures, and vice versa at 13C. Differences between the groups were also observed in the photosynthetic yields. These results reveal the expression of allopatric speciation in several phenotypic characters, providing a functional dimension to the cryptic, or rather pseudo-cryptic, diversity observed within C. socialis. We believe that such an integrated approach is useful for robust taxonomic and functional delimitations of presumed cosmopolitan microorganisms.