Draft genome sequence and genetic transformation of the oleaginous alga Nannochloropsis gaditana

TLDR

Algae are increasingly considered for biofuel production due to their high photoautotrophic biomass and lipid yields, yet existing model species are not competitive production strains. This study provides a draft genome sequence and a genetic transformation method for *Nannochloropsis gaditana* CCMP526 to enable lipid biosynthesis research and biofuel development. The draft genome (≈29 Mb nuclear, organellar) contains 9,052 genes, with annotated glycerolipid biogenesis genes and differential regulation under nitrogen limitation, and phylogenomics reveals unique photosynthesis genes and expansions linked to its photoautotrophic traits. *N.

Abstract

The potential use of algae in biofuels applications is receiving significant attention. However, none of the current algal model species are competitive production strains. Here we present a draft genome sequence and a genetic transformation method for the marine microalga Nannochloropsis gaditana CCMP526. We show that N. gaditana has highly favourable lipid yields, and is a promising production organism. The genome assembly includes nuclear (~29 Mb) and organellar genomes, and contains 9,052 gene models. We define the genes required for glycerolipid biogenesis and detail the differential regulation of genes during nitrogen-limited lipid biosynthesis. Phylogenomic analysis identifies genetic attributes of this organism, including unique stramenopile photosynthesis genes and gene expansions that may explain the distinguishing photoautotrophic phenotypes observed. The availability of a genome sequence and transformation methods will facilitate investigations into N. gaditana lipid biosynthesis and permit genetic engineering strategies to further improve this naturally productive alga. Algae show much promise in the production of biofuels owing to their high photoautotrophic biomass and lipid production rates. In this study, the draft genome ofNannochloropsis gaditanaCCMP526 and a method for the transformation of this alga are reported, facilitating the investigation of lipid synthesis and biofuel production.