title: Fatty acid composition of developing tree peony (Paeonia section Moutan DC.) seeds and transcriptome analysis during seed development.
abstract: BACKGROUND
  Tree peony (Paeonia section Moutan DC.) is known for its excellent ornamental and medicinal values. In 2011, seeds from P. ostii have been identified as novel resource of α-linolenic acid (ALA) for seed oil production and development in China. However, the molecular mechanism on biosynthesis of unsaturated fatty acids in tree peony seeds remains unknown. Therefore, transcriptome data is needed to better understand the underlying mechanisms.
  
  
  RESULTS
  In this study, lipid accumulation contents were measured using GC-MS methods across developing tree peony seeds, which exhibited an extraordinary ALA content (49.3%) in P. ostii mature seeds. Transcriptome analysis was performed using Illumina sequencing platform. A total of 144 million 100-bp paired-end reads were generated from six libraries, which identified 175,874 contigs. In the KEGG Orthology enrichment of differentially expressed genes, lipid metabolism pathways were highly represented categories. Using this data we identified 388 unigenes that may be involved in de novo fatty acid and triacylglycerol biosynthesis. In particular, three unigenes (SAD, FAD2 and FAD8) encoding fatty acid desaturase with high expression levels in the fast oil accumulation stage compared with the initial stage of seed development were identified.
  
  
  CONCLUSIONS
  This study provides the first comprehensive genomic resources characterizing tree peony seeds gene expression at the transcriptional level. These data lay the foundation for further understanding of molecular mechanism responsible for lipid biosynthesis and the high unsaturated fatty acids (especially ALA) accumulation. Meanwhile, it provides theoretical base for potential oilseed application in the respect of n-6 to n-3 ratio for human diets and future regulation of target healthy components of oils.
authors.affiliation: Key Laboratory of Plant Resources and Beijing Botanical Garden, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China. shshli@ibcas.ac.cn.|University of Chinese Academy of Sciences, Beijing, 100049, China. shshli@ibcas.ac.cn.
authors.forename: Shan-Shan
authors.initials: SS
authors.lastname: Li
authors.affiliation: Key Laboratory of Plant Resources and Beijing Botanical Garden, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China. wanglsh@ibcas.ac.cn.
authors.forename: Liang-Sheng
authors.initials: LS
authors.lastname: Wang
authors.affiliation: Key Laboratory of Plant Resources and Beijing Botanical Garden, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China. shuqy@ibcas.ac.cn.
authors.forename: Qing-Yan
authors.initials: QY
authors.lastname: Shu
authors.affiliation: Key Laboratory of Plant Resources and Beijing Botanical Garden, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China. wujie1987519@163.com.|University of Chinese Academy of Sciences, Beijing, 100049, China. wujie1987519@163.com.
authors.forename: Jie
authors.initials: J
authors.lastname: Wu
authors.affiliation: Institute of Forest Protection, Chinese Academy of Forestry, Beijing, 100091, China. van--hen@163.com.
authors.forename: Li-Guang
authors.initials: LG
authors.lastname: Chen
authors.affiliation: Key Laboratory of Plant Resources and Beijing Botanical Garden, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China. ss7037@163.com.|College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, China. ss7037@163.com.
authors.forename: Shuai
authors.initials: S
authors.lastname: Shao
authors.affiliation: Key Laboratory of Plant Resources and Beijing Botanical Garden, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China. 847376846@qq.com.|University of Chinese Academy of Sciences, Beijing, 100049, China. 847376846@qq.com.
authors.forename: Dan-Dan
authors.initials: DD
authors.lastname: Yin
mesh_terms: D053898:Biosynthetic Pathways; D019295:Computational Biology; D005227:Fatty Acids / Q000378:metabolism*; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D059014:High-Throughput Nucleotide Sequencing; D050356:Lipid Metabolism; D058977:Molecular Sequence Annotation; D029596:Paeonia / Q000235:genetics* / Q000378:metabolism*; D010641:Phenotype; D012639:Seeds / Q000235:genetics* / Q000378:metabolism*; D059467:Transcriptome
chemical_list: D005227:Fatty Acids