title: NUCLEAR MONOPLOIDY AND ASEXUAL PROPAGATION OF NANNOCHLOROPSIS OCEANICA (EUSTIGMATOPHYCEAE) AS REVEALED BY ITS GENOME SEQUENCE(1).
abstract: Species in genus Nannochloropsis are promising candidates for both biofuel and biomass production due to their ability to accumulate rich fatty acids and grow fast; however, their sexual reproduction has not been studied. It is clear that the construction of their metabolic pathways, such as that of polyunsaturated fatty acid (PUFA) biosynthesis, and understanding of their biological characteristics, such as nuclear ploidy and reproductive strategy, will certainly facilitate their genetic improvement through gene engineering and mutation and clonal expansion. In this study, the genome of N. oceanica S. Suda et Miyashita was sequenced with the next-generation Illumina GA sequencing technologies. The genome was ∼30 Mb in size, which contained 11,129 protein-encoding genes. Of them, 59.65% were annotated by aligning with those in diverse protein databases, and 29.68% were assigned at least one function described in the Kyoto Encyclopedia of Genes and Genomes (KEGG) database. Less frequent polymorphic nucleotides (one in 22.06 kb) and the obvious deviation from 1:1 (major:minor, minor ≥10) expectation indicated the nuclear monoploidy of N. oceanica. The lack of the majority of meiosis-specific proteins implied the asexual reproduction of this alga. In combination, the nuclear monoploidy and asexual propagation led us to favor the hypothesis that N. oceanica was a premeiotic or ameiotic alga. In addition, sequence similarity-based searching identified the elongase- and desaturase-encoding genes involved in the biosynthesis of long-chain PUFAs, which provided the genetic basis of its rich content of eicosapentaenoic acid (EPA). The functional genes and their metabolic pathways profiled against its genome sequence will facilitate its integrative investigations.
authors.affiliation: Key Laboratory of Mariculture of Chinese Ministry of Education, Ocean University of China, Qingdao 266003, China Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing 100029, China Graduate University of Chinese Academy of Sciences, Beijing 100049, China Beijing Genomics Institute (BGI) at Shenzhen, Shenzhen 518083, ChinaKey Laboratory of Marine Genetics and Breeding of Chinese Ministry of Education, Ocean University of China, Qingdao 266003, ChinaBeijing Genomics Institute (BGI) at Shenzhen, Shenzhen 518083, ChinaKey Laboratory of Mariculture of Chinese Ministry of Education, Ocean University of China, Qingdao 266003, ChinaBeijing Genomics Institute (BGI) at Shenzhen, Shenzhen 518083, ChinaCollege of Medicine and Drugs, Ocean University of China, Qingdao 266003, ChinaKey Laboratory of Marine Genetics and Breeding of Chinese Ministry of Education, Ocean University of China, Qingdao 266003, ChinaBeijing Genomics Institute (BGI) at Shenzhen, Shenzhen 518083, China.
authors.forename: Kehou
authors.initials: K
authors.lastname: Pan
authors.affiliation: Key Laboratory of Mariculture of Chinese Ministry of Education, Ocean University of China, Qingdao 266003, China Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing 100029, China Graduate University of Chinese Academy of Sciences, Beijing 100049, China Beijing Genomics Institute (BGI) at Shenzhen, Shenzhen 518083, ChinaKey Laboratory of Marine Genetics and Breeding of Chinese Ministry of Education, Ocean University of China, Qingdao 266003, ChinaBeijing Genomics Institute (BGI) at Shenzhen, Shenzhen 518083, ChinaKey Laboratory of Mariculture of Chinese Ministry of Education, Ocean University of China, Qingdao 266003, ChinaBeijing Genomics Institute (BGI) at Shenzhen, Shenzhen 518083, ChinaCollege of Medicine and Drugs, Ocean University of China, Qingdao 266003, ChinaKey Laboratory of Marine Genetics and Breeding of Chinese Ministry of Education, Ocean University of China, Qingdao 266003, ChinaBeijing Genomics Institute (BGI) at Shenzhen, Shenzhen 518083, China.
authors.forename: Junjie
authors.initials: J
authors.lastname: Qin
authors.affiliation: Key Laboratory of Mariculture of Chinese Ministry of Education, Ocean University of China, Qingdao 266003, China Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing 100029, China Graduate University of Chinese Academy of Sciences, Beijing 100049, China Beijing Genomics Institute (BGI) at Shenzhen, Shenzhen 518083, ChinaKey Laboratory of Marine Genetics and Breeding of Chinese Ministry of Education, Ocean University of China, Qingdao 266003, ChinaBeijing Genomics Institute (BGI) at Shenzhen, Shenzhen 518083, ChinaKey Laboratory of Mariculture of Chinese Ministry of Education, Ocean University of China, Qingdao 266003, ChinaBeijing Genomics Institute (BGI) at Shenzhen, Shenzhen 518083, ChinaCollege of Medicine and Drugs, Ocean University of China, Qingdao 266003, ChinaKey Laboratory of Marine Genetics and Breeding of Chinese Ministry of Education, Ocean University of China, Qingdao 266003, ChinaBeijing Genomics Institute (BGI) at Shenzhen, Shenzhen 518083, China.
authors.forename: Si
authors.initials: S
authors.lastname: Li
authors.affiliation: Key Laboratory of Mariculture of Chinese Ministry of Education, Ocean University of China, Qingdao 266003, China Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing 100029, China Graduate University of Chinese Academy of Sciences, Beijing 100049, China Beijing Genomics Institute (BGI) at Shenzhen, Shenzhen 518083, ChinaKey Laboratory of Marine Genetics and Breeding of Chinese Ministry of Education, Ocean University of China, Qingdao 266003, ChinaBeijing Genomics Institute (BGI) at Shenzhen, Shenzhen 518083, ChinaKey Laboratory of Mariculture of Chinese Ministry of Education, Ocean University of China, Qingdao 266003, ChinaBeijing Genomics Institute (BGI) at Shenzhen, Shenzhen 518083, ChinaCollege of Medicine and Drugs, Ocean University of China, Qingdao 266003, ChinaKey Laboratory of Marine Genetics and Breeding of Chinese Ministry of Education, Ocean University of China, Qingdao 266003, ChinaBeijing Genomics Institute (BGI) at Shenzhen, Shenzhen 518083, China.
authors.forename: Wenkui
authors.initials: W
authors.lastname: Dai
authors.affiliation: Key Laboratory of Mariculture of Chinese Ministry of Education, Ocean University of China, Qingdao 266003, China Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing 100029, China Graduate University of Chinese Academy of Sciences, Beijing 100049, China Beijing Genomics Institute (BGI) at Shenzhen, Shenzhen 518083, ChinaKey Laboratory of Marine Genetics and Breeding of Chinese Ministry of Education, Ocean University of China, Qingdao 266003, ChinaBeijing Genomics Institute (BGI) at Shenzhen, Shenzhen 518083, ChinaKey Laboratory of Mariculture of Chinese Ministry of Education, Ocean University of China, Qingdao 266003, ChinaBeijing Genomics Institute (BGI) at Shenzhen, Shenzhen 518083, ChinaCollege of Medicine and Drugs, Ocean University of China, Qingdao 266003, ChinaKey Laboratory of Marine Genetics and Breeding of Chinese Ministry of Education, Ocean University of China, Qingdao 266003, ChinaBeijing Genomics Institute (BGI) at Shenzhen, Shenzhen 518083, China.
authors.forename: Baohua
authors.initials: B
authors.lastname: Zhu
authors.affiliation: Key Laboratory of Mariculture of Chinese Ministry of Education, Ocean University of China, Qingdao 266003, China Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing 100029, China Graduate University of Chinese Academy of Sciences, Beijing 100049, China Beijing Genomics Institute (BGI) at Shenzhen, Shenzhen 518083, ChinaKey Laboratory of Marine Genetics and Breeding of Chinese Ministry of Education, Ocean University of China, Qingdao 266003, ChinaBeijing Genomics Institute (BGI) at Shenzhen, Shenzhen 518083, ChinaKey Laboratory of Mariculture of Chinese Ministry of Education, Ocean University of China, Qingdao 266003, ChinaBeijing Genomics Institute (BGI) at Shenzhen, Shenzhen 518083, ChinaCollege of Medicine and Drugs, Ocean University of China, Qingdao 266003, ChinaKey Laboratory of Marine Genetics and Breeding of Chinese Ministry of Education, Ocean University of China, Qingdao 266003, ChinaBeijing Genomics Institute (BGI) at Shenzhen, Shenzhen 518083, China.
authors.forename: Yuanchun
authors.initials: Y
authors.lastname: Jin
authors.affiliation: Key Laboratory of Mariculture of Chinese Ministry of Education, Ocean University of China, Qingdao 266003, China Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing 100029, China Graduate University of Chinese Academy of Sciences, Beijing 100049, China Beijing Genomics Institute (BGI) at Shenzhen, Shenzhen 518083, ChinaKey Laboratory of Marine Genetics and Breeding of Chinese Ministry of Education, Ocean University of China, Qingdao 266003, ChinaBeijing Genomics Institute (BGI) at Shenzhen, Shenzhen 518083, ChinaKey Laboratory of Mariculture of Chinese Ministry of Education, Ocean University of China, Qingdao 266003, ChinaBeijing Genomics Institute (BGI) at Shenzhen, Shenzhen 518083, ChinaCollege of Medicine and Drugs, Ocean University of China, Qingdao 266003, ChinaKey Laboratory of Marine Genetics and Breeding of Chinese Ministry of Education, Ocean University of China, Qingdao 266003, ChinaBeijing Genomics Institute (BGI) at Shenzhen, Shenzhen 518083, China.
authors.forename: Wengong
authors.initials: W
authors.lastname: Yu
authors.affiliation: Key Laboratory of Mariculture of Chinese Ministry of Education, Ocean University of China, Qingdao 266003, China Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing 100029, China Graduate University of Chinese Academy of Sciences, Beijing 100049, China Beijing Genomics Institute (BGI) at Shenzhen, Shenzhen 518083, ChinaKey Laboratory of Marine Genetics and Breeding of Chinese Ministry of Education, Ocean University of China, Qingdao 266003, ChinaBeijing Genomics Institute (BGI) at Shenzhen, Shenzhen 518083, ChinaKey Laboratory of Mariculture of Chinese Ministry of Education, Ocean University of China, Qingdao 266003, ChinaBeijing Genomics Institute (BGI) at Shenzhen, Shenzhen 518083, ChinaCollege of Medicine and Drugs, Ocean University of China, Qingdao 266003, ChinaKey Laboratory of Marine Genetics and Breeding of Chinese Ministry of Education, Ocean University of China, Qingdao 266003, ChinaBeijing Genomics Institute (BGI) at Shenzhen, Shenzhen 518083, China.
authors.forename: Guanpin
authors.initials: G
authors.lastname: Yang
authors.affiliation: Key Laboratory of Mariculture of Chinese Ministry of Education, Ocean University of China, Qingdao 266003, China Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing 100029, China Graduate University of Chinese Academy of Sciences, Beijing 100049, China Beijing Genomics Institute (BGI) at Shenzhen, Shenzhen 518083, ChinaKey Laboratory of Marine Genetics and Breeding of Chinese Ministry of Education, Ocean University of China, Qingdao 266003, ChinaBeijing Genomics Institute (BGI) at Shenzhen, Shenzhen 518083, ChinaKey Laboratory of Mariculture of Chinese Ministry of Education, Ocean University of China, Qingdao 266003, ChinaBeijing Genomics Institute (BGI) at Shenzhen, Shenzhen 518083, ChinaCollege of Medicine and Drugs, Ocean University of China, Qingdao 266003, ChinaKey Laboratory of Marine Genetics and Breeding of Chinese Ministry of Education, Ocean University of China, Qingdao 266003, ChinaBeijing Genomics Institute (BGI) at Shenzhen, Shenzhen 518083, China.
authors.forename: Dongfang
authors.initials: D
authors.lastname: Li
keywords: Nannochloropsis oceanica; asexual reproduction; genome sequencing; monoploidy; polyunsaturated fatty acid