The root of Bupleurum chinense DC. is the major source of Radix Bupleuri and widely used for the treatment of inflammatory disorders and infectious diseases in Asia. However, the excessive reproductive growth of B. chinense DC. strongly interferes with its root biomass accumulation and secondary metabolite biosynthesis. Although inflorescence removal or disbudding has been used to improve the yield and quality in rhizome crops, the molecular mechanism is unknown. Here, we compared the differences between the control groups and the continuous inflorescence removal (CIR) treatment groups of B. chinense DC. on physiological, chemical and molecular levels. The results of 2-year field experiments showed that the primary root length and biomass accumulation, as well as the saikosaponin a and d (SS-a and SS-d) contents were all increased under CIR treatment. Illumina sequencing of cDNA libraries prepared from the roots of control groups and CIR groups during four flowering stages identified 172, 243, 1974 and 3024 differentially expressed genes (DEGs) respectively. Most DEGs were involved in brassinolide (BR) signal transduction, jasmonic acid (JA) signal tranduction, 2-methyl-d-erythritol-4-phosphate pathway/Mevalonate (MVA/MEP) pathways and SS pathways. There were 295 differentially expressed transcription factors (TFs) including members of the MYB, bHLH, bZIP, and NAC families that also induced by CIR treatment. Irrigation experiments further showed that 0.05 mg/L exogenous BR improved the root fresh weight and the root/shoot ratio of B. chinense DC. mainly through cyclin D3, BIR1, BSK1 and ARFs; the SS-a and SS-d contents in the roots of B. chinense DC. were increased under 100 mM exogenous Me-JA treatment, most genes involved in MVA, MEP and SS pathways were activated. In all, this study not only provides new insights into the fundamental mechanism underlying the poorly studied inflorescence removal process in B. chinense DC. and other rhizome crops, but also represents an important resource for future research on gene functions during CIR treatment or the reproductive stage.

柴胡DC的根。是柴胡的主要来源，广泛用于治疗亚洲的炎症性疾病和传染病。然而，中华芽孢杆菌DC过度繁殖。强烈干扰其根系生物量的积累和次生代谢产物的生物合成。尽管去除花序或喷出花序已被用来提高根茎作物的产量和品质，但其分子机理尚不清楚。在这里，我们比较了对照组和连续花序摘除（CIR）治疗组之间的差异。DC。在生理，化学和分子水平上。两年田间试验的结果表明，在CIR处理下，初生根长度和生物量积累以及皂苷a和d（SS-a和SS-d）的含量均增加。从四个开花阶段的对照组和CIR组的根制备的cDNA文库的Illumina测序分别鉴定出172、243、1974和3024个差异表达基因（DEG）。大多数DEG参与油菜素内酯（BR）信号转导，茉莉酸（JA）信号转导，2-甲基-d-赤藓糖醇-4-磷酸途径/甲羟戊酸（MVA / MEP）途径和SS途径。有295个差异表达的转录因子（TF），包括MYB，bHLH，bZIP和NAC家族的成员，它们也通过CIR处理诱导。B.中华ense。主要通过细胞周期素D3，BIR1，BSK1和ARFs ; B. chinense DC根中的SS-a和SS-d含量。在100 mM外源Me-JA处理下，这些蛋白的表达增加，大多数参与MVA，MEP和SS途径的基因被激活。总而言之，这项研究不仅提供了对B. chinense DC中花序去除过程研究不足的基本机制的新见解。和其他根茎作物，也代表了在CIR治疗或生殖阶段基因功能未来研究的重要资源。