Ttranscriptome Analysis Of The Formation Of Dragon's Blood In Dracaena Cambodiana

Dragon's blood is a traditional medicine mainly derived from Dracaena plants. The major components of dragon's blood are flavonoids and homoisoflavanoids. Owing to a lack of reports of the molecular biosynthesis and the regulation of formation in Dracaena plants remain unknown. Here, we performed RNA sequencing (RNA-seq) of three cDNA libraries generated from different time after injecting patent induction solution into the stem of Dracaena cambodiana.Changes of compounds in the dragon's blood at early stage of induction was detected by HPLC-MS. Five flavonoids compounds including the two chalcones ketones, two flavans and1homoisoflavonoids was identificated by the pure compounds separated from dragon's blood.RNA-seq generated266.57M raw reads on the Illumina platform. A total of81322unigenes over400bp in size were obtained and subjected to further analyses. A similarity search against the non-redundant (nr) protein database returned34783(42.77%) positive BLASTx hits. The transcriptome analysis was annotated using the clusters of gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG). Of those unigenes associated with dragon's blood formation,20putatively encoded enzymes in the flavonoids biosynthesis pathway, and a handful of transcription factors and protein kinases were related to treatment by injection. Digital gene expression (DGE) profiling to investigate the transcriptional changes during injection and were certificated by qPCR.Four bHLH type transcription factor genes (DcbHLHI?DcbHLH2?DcbHLH3? DcbHLH4) were cloned. Bioinformatics analysis shows they divided into three categories and both contain helix-loop-helix structure. They recognized the cis-element of E-box and were studied clearly as the regulators of flavonoid compounds in model plants. The four bHLHs tanscript levels in different tissues were examined using real-time PCR. DcbHLHl, DcbHLH3, DcbHLH4were high expression in plant leaves while DcbHLH2express higher in plant stem. Their expression in root were the lowest. This specificity of organization may be related to different functions of regulation related to flavonoids compounds.