Nannochloropsis Genomes Reveal Evolution of Microalgal Oleaginous Traits

Dongmei Wang, Kang Ning, Jing Li, Jianqiang Hu, Danxiang Han, Hui Wang, Xiaowei Zeng, Xiaoyan Jing, Qian Zhou, Xiaoquan Su, Xingzhi Chang, Anhui Wang, Wei Wang, Jing Jia, Li Wei, Yi Xin, Yinghe Qiao, Ranran Huang, Jie Chen, Bo HanKangsup Yoon, Russell T. Hill, Yonathan Zohar, Feng Chen, Qiang Hu, Jian Xu

Research output: Contribution to journalArticle

142 Scopus citations

Abstract

Oleaginous microalgae are promising feedstock for biofuels, yet the genetic diversity, origin and evolution of oleaginous traits remain largely unknown. Here we present a detailed phylogenomic analysis of five oleaginous Nannochloropsis species (a total of six strains) and one time-series transcriptome dataset for triacylglycerol (TAG) synthesis on one representative strain. Despite small genome sizes, high coding potential and relative paucity of mobile elements, the genomes feature small cores of ca. 2,700 protein-coding genes and a large pan-genome of >38,000 genes. The six genomes share key oleaginous traits, such as the enrichment of selected lipid biosynthesis genes and certain glycoside hydrolase genes that potentially shift carbon flux from chrysolaminaran to TAG synthesis. The eleven type II diacylglycerol acyltransferase genes (DGAT-2) in every strain, each expressed during TAG synthesis, likely originated from three ancient genomes, including the secondary endosymbiosis host and the engulfed green and red algae. Horizontal gene transfers were inferred in most lipid synthesis nodes with expanded gene doses and many glycoside hydrolase genes. Thus multiple genome pooling and horizontal genetic exchange, together with selective inheritance of lipid synthesis genes and species-specific gene loss, have led to the enormous genetic apparatus for oleaginousness and the wide genomic divergence among present-day Nannochloropsis. These findings have important implications in the screening and genetic engineering of microalgae for biofuels.

Original languageEnglish (US)
Article numbere1004094
JournalPLoS genetics
Volume10
Issue number1
DOIs
StatePublished - Jan 2014

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Molecular Biology
  • Genetics
  • Genetics(clinical)
  • Cancer Research

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    Wang, D., Ning, K., Li, J., Hu, J., Han, D., Wang, H., Zeng, X., Jing, X., Zhou, Q., Su, X., Chang, X., Wang, A., Wang, W., Jia, J., Wei, L., Xin, Y., Qiao, Y., Huang, R., Chen, J., ... Xu, J. (2014). Nannochloropsis Genomes Reveal Evolution of Microalgal Oleaginous Traits. PLoS genetics, 10(1), [e1004094]. https://doi.org/10.1371/journal.pgen.1004094