Regulatory Networks of Flowering Genes in <i>Angelica sinensis</i> during Vernalization

<i>Angelica sinensis</i> is a low-temperature and long-day perennial herb that has been widely used for cardio-cerebrovascular diseases in recent years. In commercial cultivation, up to 40% of flowering decreases the officinal yield of roots and accumulation of bioactive compounds. Although the regulatory mechanism of flowering genes during the photoperiod has been revealed, the networks during vernalization have not been mapped. Here, transcriptomics profiles of <i>A. sinensis</i> with uncompleted (T1), completed (T2) and avoided vernalization (T3) were performed using RNA-seq, and genes expression was validated with qRT-PCR. A total of 61,241 isoforms were annotated on KEGG, KOG, Nr and Swiss-Prot databases; 4212 and 5301 differentially expressed genes (DEGs) were observed; and 151 and 155 genes involved in flowering were dug out at T2 vs. T1 and T3 vs. T1, respectively. According to functional annotation, 104 co-expressed genes were classified into six categories: FLC expression (22; e.g., <i>VILs</i>, <i>FCA</i> and <i>FLK</i>), sucrose metabolism (12; e.g., <i>TPSs</i>, <i>SUS3</i> and <i>SPSs</i>), hormone response (18; e.g., <i>GID1B</i>, <i>RAP2s</i> and <i>IAAs</i>), circadian clock (2; i.e., <i>ELF3</i> and <i>COR27</i>), downstream floral integrators and meristem identity (15; e.g., <i>SOC1</i>, <i>AGL65</i> and <i>SPLs</i>) and cold response (35; e.g., <i>PYLs</i>, <i>ERFs</i> and <i>CORs</i>). The expression levels of candidate genes were almost consistent with FPKM values and changes in sugar and hormone contents. Based on their functions, four pathways that regulate flowering during vernalization were mapped, including the vernalization pathway, the autonomic pathway, the age pathway and the GA (hormone) pathway. This transcriptomic analysis provides new insights into the gene-regulatory networks of flowering in <i>A. sinensis</i>.