Transcriptome of tung tree sees with emphasis on genes from lipid metabolism. Vernicia fordii

Tung oil, the major product of tung tree (Vernicia fordii) seeds, is one of the highest quality oils for industrial applications and has been considered to the production of biodiesel. Because of the poor agronomical traits of this crop, efforts have been made to breed tung tree for higher fruit yield and for modification of oil properties to be used as biodiesel, or to engineer higher yielding plants to produce tung oil. However, these efforts have been hampered by the lack of molecular information since there is no available genome and the identified and characterized transcripts of tung are scarce. Furthermore, there are still many knowledge gaps regarding tung oil biosynthesis. To provide a comprehensive and accurate foundation for molecular studies of tung tree, herein we present the reference transcriptome dataset of tung mature seeds. A set of 43,081,927 ESTs were assembled into 47,585 unigenes. The homology search using blastx against the GenBank non-redundant protein database and the Swiss-Prot database resulted in the annotation of 96 % and 81% of the unigenes, respectively. We also systematically arranged the series of transcripts potentially associated with oil biosynthesis and breakdown and examined the expression profile of a subset of those genes in samples from different stages of seed development, providing a valuable source of genes and transcriptional information related to these pathways. This study represents the first large-scale transcriptome annotation of tung tree seeds and will be useful to breed tung for oil properties and other agronomical traits. Overall design: Transcriptome analysis in a mature seed library of Vernicia fordii by deep sequencing (Illumina HiSeq2000).