Génomique Métabolique, Genoscope, Institut de Biologie François Jacob, Commissariat à l'Énergie Atomique (CEA), CNRS, Université Évry, Université Paris-Saclay, 91057 Évry, France.
Research Federation for the Study of Global Ocean Systems Ecology and Evolution, FR2022/Tara Oceans GOSEE, 3 rue Michel-Ange, 75016 Paris, France.
Genes (Basel). 2020 Jan 7;11(1):66. doi: 10.3390/genes11010066.
Among marine phytoplankton, Mamiellales encompass several species from the genera , and , which are important contributors to primary production. Previous studies based on single gene markers described their wide geographical distribution but led to discussion because of the uneven taxonomic resolution of the method. Here, we leverage genome sequences for six Mamiellales species, two from each genus , and to investigate their distribution across 133 stations sampled during the Oceans expedition. Our study confirms the cosmopolitan distribution of Mamiellales and further suggests non-random distribution of species, with two triplets of co-occurring genomes associated with different temperatures: , and were found in colder waters, whereas spp. RCC809, spp. TOSAG39-1 and were more abundant in warmer conditions. We also report the distribution of the two candidate mating-types of for which the frequency of sexual reproduction was previously assumed to be very low. Indeed, both mating types were systematically detected together in agreement with either frequent sexual reproduction or the high prevalence of a diploid stage. Altogether, these analyses provide novel insights into Mamiellales' biogeography and raise novel testable hypotheses about their life cycle and ecology.
在海洋浮游植物中，Mamiellales 包含了几个属的几个物种，包括、和，它们是初级生产力的重要贡献者。先前基于单一基因标记的研究描述了它们广泛的地理分布，但由于方法的分类分辨率不均匀，因此引发了讨论。在这里，我们利用六个 Mamiellales 物种的基因组序列（每个属两个物种），调查它们在 2018 年海洋考察期间在 133 个采样点的分布情况。我们的研究证实了 Mamiellales 的世界性分布，并进一步表明了物种的非随机分布，与不同温度相关的三个物种对与不同的温度相关：、和 在较冷的水域中发现，而 spp. RCC809、 spp. TOSAG39-1 和 则在温暖的条件下更为丰富。我们还报告了 的两个候选交配型的分布情况，此前认为其有性生殖的频率非常低。事实上，两种交配型都被系统地一起检测到，这与频繁的有性生殖或二倍体阶段的高流行率一致。总的来说，这些分析为 Mamiellales 的生物地理学提供了新的见解，并提出了关于其生命周期和生态学的新的可检验假设。
