Transcriptome and digital gene expression analysis unravels the novel mechanism of early flowering in Angelica sinensis.

Angelica sinensis (Oliv.) Diels is a widely used medicinal plant mainly originated in Gansu, China. Angelica sinensis is greatly demanded in the clinical practice of Chinese medicine due to its broad pharmacological activities of hematopoietic and anti-inflammatory properties. But, the percentage of early flowering in Angelica sinensis arrives to 20%~30%, which severely affects its quality and quantity. Here, transcriptome profiling and digital gene expression analysis were applied to study the mechanism of early flowering in Angelica sinensis. A total of 49,183,534 clean reads were obtained and assembled into 68,262 unigenes, and 49,477 unigenes (72.5%) could be annotated to a minimum of one database in the Nr, Nt, Swiss-Pro, GO, COG and KEGG. Taking the above transcriptome data as a reference, digital gene expression result showed that 5,094 genes expression level were significant changed during early flowering. These annotated genes offered much information promoting that the biosynthesis of secondary metabolites pathway, the hormone signal transduction pathway, and the transcription regulation system may be closely related to the early flowering phenomenon of Angelica sinensis. Further expression patterns of key genes contribute to early flowering were analyzed using quantitative real-time PCR. The transcriptome result offered important gene expression information about early flowering in Angelica sinensis.