Département de biochimie, de microbiologie et de bio-informatique, Institut de Biologie Intégrative et des Systèmes, Université Laval, Québec, QC, G1V 0A6, Canada.
Department of Biology, Illinois Institute of Technology, Chicago, IL, 60616, USA.
Nat Commun. 2019 Sep 6;10(1):4061. doi: 10.1038/s41467-019-12014-x.
Tiny marine green algae issued from two deep branches of the Chlorophyta, the Mamiellophyceae and Chloropicophyceae, dominate different regions of the oceans and play key roles in planktonic communities. Considering that the Mamiellophyceae is the sole lineage of prasinophyte algae that has been intensively investigated, the extent to which these two algal groups differ in their metabolic capacities and cellular processes is currently unknown. To address this gap of knowledge, we investigate here the nuclear genome sequence of a member of the Chloropicophyceae, Chloropicon primus. Among the main biological insights that emerge from this 17.4 Mb genome, we find an unexpected diploid structure for most chromosomes and a propionate detoxification pathway in green algae. Our results support the notion that separate events of genome minimization, which entailed differential losses of genes/pathways, have occurred in the Chloropicophyceae and Mamiellophyceae, suggesting different strategies of adaptation to oceanic environments.
微小的海洋绿藻源自绿藻门的两个深枝，即绿藻纲和黄藻纲，它们分别在海洋的不同区域占主导地位，并在浮游生物群落中发挥关键作用。考虑到绿藻纲是被广泛研究的甲藻的唯一谱系，这两个藻类群体在代谢能力和细胞过程方面的差异程度目前尚不清楚。为了解决这一知识空白，我们在这里研究了黄藻纲成员 Chloropicon primus 的核基因组序列。从这个 17.4Mb 的基因组中得出的主要生物学见解之一是，我们发现大多数染色体的二倍体结构和绿藻中的丙酸解毒途径令人意外。我们的研究结果表明，基因组最小化的独立事件已经在黄藻纲和绿藻纲中发生，这涉及到基因/途径的差异丢失，这表明它们适应海洋环境的策略不同。
