Genome Sequence of Chrysotila roscoffensis, a Coccolithphore Contributed to Global Biogeochemical Cycles

Ran Meng,Lin Zhang,Xiaojun Yan,Jilin Xu,Qijun Luo,Chengxu Zhou,Xiaodi Hu,Kai Liao,Yanze Cui,Peng Xiao

doi:10.3390/genes13010040

Ran Meng, Lin Zhang + Show 8 more

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https://doi.org/10.3390/genes13010040

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Abstract

Chrysotila is a genus of coccolithophores. Together with Emiliania, it is one of the representative genera in the Haptophyta which have been extensively studied. They are photosynthetic unicellular marine algae sharing the common characteristic of the production of CaCO3 platelets (coccoliths) on the surface of their cells and are crucial contributors to global biogeochemical cycles. Here, we report the genome assembly of Chrysotila roscoffensis. The assembled genome size was ~636 Mb distributed across 769 scaffolds with N50 of 1.63 Mb, and maximum contig length of ~2.6 Mb. Repetitive elements accounted for approximately 59% of the genome. A total of 23,341 genes were predicted from C. roscoffensis genome. The divergence time between C. roscoffensis and Emiliania huxleyi was estimated to be around 537.6 Mya. Gene families related to cytoskeleton, cellular motility and morphology, and ion transport were expanded. The genome of C. roscoffensis will provide a foundation for understanding the genetic and phenotypic diversification and calcification mechanisms of coccolithophores.

Highlights

Coccolithophores, belonging to the Haptophyta, are photosynthetic unicellular marine algae sharing the common characteristic of the production of CaCO3 platelets on the surface of their cells
We report on the assembly and annotation of the C. roscoffensis genome
The results show that 58.54% of C. roscoffensis genome consists of repetitive elements (Table 4)

Summary

Introduction

Coccolithophores, belonging to the Haptophyta, are photosynthetic unicellular marine algae sharing the common characteristic of the production of CaCO3 platelets (coccoliths) on the surface of their cells. They are globally distributed across all oceans except the polar ones, with some species forming blooms that can be observed from artificial satellites [1]. Coccolithophores play a fundamental role in the marine carbon cycle through the fixation of inorganic carbon by photosynthesis (the organic carbon pump) and the export of CO2 during calcification (the carbonate counter pump) [2] They are thought to be responsible for about 10% of global carbon fixation [3] and to produce up to 50%. Coccoliths provide ballast that drives the transfer of particulate organic matter to the deep ocean [6]

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