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| Background: Longan, a famous tropical/subtropical woody fruit in Southeast Asia. However, progress in the molecular mechanism of longan embryogenesis influencing yield and quality is slow by lack of transcriptomic and genomic information. Illumina second generation sequencing is suitable for generating enormous transcript sequences for functional genomic analysis for non-model species with un-sequenced genomes such as longan.Results: Longan EC(embryogenic callus) cDNA library was sequenced by Illumina HiSeq2000. The total of 64,876,258 clean reads with 5.84 Gb nucleotides were assembled into 68,925 unigenes with mean length of 448 bp, and ≥1000 bp unigenes accounted for 8.26 %. Based on BLASTx, 40,634 unigenes had significant similarity with Nr and Swiss-Prot databases. 38,845 and 17,118 annotated unigenes were respectively assigned to GO categories with 43 sub-categories and COG group with 25 sub-groups. Additionally, 17,306 unigenes were assigned to 199 KEGG pathways, which were well represented by Metabolic pathways, Plant-pathogen interaction, Biosynthesis of secondary metabolites, and Genetic information processing. Analyses of the unigenes (≥1000 bp) revealed that not only as many as 328 unigenes concerning embryogenesis-related genes such as EMB, PPR, MEE but also many unigenes concerning reproductive growth such as flowering, gametophyte genesis and fertility, and vegetative growth such as root and shoot growth, expressed in EC, which differed remarkably from the in vivo embryogenesis reported before. Conclusions: This research firstly provided a global transcriptome dataset of longan EC. The results showed that the expressed genes of EC were that much and so various, which suggested that EC almost reflect the whole profile of S.E., even seem to be the epitome of the whole plant on the molecular level. In a word, this dataset provided a new insight into molecular mechanism of embryogenesis in longan even in other plants. |
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| Keywords:Dimocarpus longan; embryogenic callus; Illumina paired-end sequencing; transcriptome; analyses of metabolic network |
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