Duan Yuanyuan, Wu Jiaqi, Wang Fanfan, Zhang Kaiqi, Guo Xiaoliang, Tang Tao, Mu Sen, You Jingmao, Guo Jie
Key Laboratory of Biology and Cultivation of Chinese Herbal Medicines, Ministry of Agriculture and Rural Affairs, Institute of Chinese Herbal Medicines, Hubei Academy of Agricultural Sciences, Enshi, China.
Hubei Engineering Research Center of Under-forest Economy, Hubei Academy of Agricultural Sciences, Wuhan, China.
Front Plant Sci. 2023 Feb 15;14:1132936. doi: 10.3389/fpls.2023.1132936. eCollection 2023.
The bulb of , a traditional cough and expectorant medicine, is usually harvested from June to September according to traditional cultivation experience, without practical scientific guidance. Although steroidal alkaloid metabolites have been identified in , the dynamic changes in their levels during bulb development and their molecular regulatory mechanisms are poorly understood.
In this study, integrative analyses of the bulbus phenotype, bioactive chemical investigations, and metabolome and transcriptome profiles were performed to systematically explore the variations in steroidal alkaloid metabolite levels and identify the genes modulating their accumulation and the corresponding regulatory mechanisms.
The results showed that weight, size, and total alkaloid content of the regenerated bulbs reached a maximum at IM03 (post-withering stage, early July), whereas peiminine content reached a maximum at IM02 (withering stage, early June). There were no significant differences between IM02 and IM03, indicating that regenerated bulbs could be harvested appropriately in early June or July. Peiminine, peimine, tortifoline, hupehenine, korseveramine, delafrine, hericenone N-oxide, korseveridine, puqiedinone, pingbeinone, puqienine B, puqienine E, pingbeimine A, jervine, and ussuriedine levels were upregulated in IM02 and IM03, compared with IM01 (vigorous growth stage, early April). The Kyoto Encyclopedia of Genes and Genomes enrichment analysis indicated that the accumulation of steroidal alkaloid metabolites mainly occurred prior to IM02. , , , , and may play a positive role in peiminine, peimine, hupehenine, korseveramine, korseveridine, hericenone N-oxide, puqiedinone, delafrine, tortifoline, pingbeinone, puqienine B, puqienine E, pingbeimine A, jervine, and ussuriedine biosynthesis, whereas the downregulation of , and may lead to a reduction in peimisine levels. Weighted gene correlation network analysis showed that , , and were negatively correlated with peiminine and pingbeimine A, whereas and were positively correlated. and may play a negative role in peimine and korseveridine biosynthesis, whereas plays a positive role. In addition, the highly expressed C2H2, HSF, AP2/ERF, HB, GRAS, C3H, NAC, MYB-related transcription factors (TFs), GARP-G2-like TFs, and WRKY may play positive roles in the accumulation of peiminine, peimine, korseveridine, and pingbeimine A.
These results provide new insights into scientific harvesting of .
川贝母是一种传统的止咳祛痰药，根据传统种植经验，其鳞茎通常在6月至9月采收，缺乏实际科学指导。虽然已在川贝母中鉴定出甾体生物碱代谢产物，但其在鳞茎发育过程中的水平动态变化及其分子调控机制尚不清楚。
在本研究中，对鳞茎表型、生物活性化学成分、代谢组和转录组图谱进行综合分析，以系统地探索甾体生物碱代谢产物水平的变化，鉴定调节其积累的基因及其相应的调控机制。
结果表明，再生鳞茎的重量、大小和总生物碱含量在IM03（枯萎后期，7月初）达到最大值，而浙贝母碱含量在IM02（枯萎期，6月初）达到最大值。IM02和IM03之间无显著差异，表明再生鳞茎可在6月初或7月初适当采收。与IM01（旺盛生长阶段，4月初）相比，IM02和IM03中浙贝母碱、贝母素、鄂贝母碱、西贝母碱、川贝母啶、去氢浙贝母碱、赫斯贝母酮N-氧化物、川贝母碱、蒲贝酮、平贝酮、蒲贝碱B、蒲贝碱E、平贝母碱A、介藜芦碱和乌苏里贝母碱水平上调。京都基因与基因组百科全书富集分析表明，甾体生物碱代谢产物的积累主要发生在IM02之前。 、 、 、 和 可能在浙贝母碱、贝母素、鄂贝母碱、西贝母碱、川贝母啶、赫斯贝母酮N-氧化物、蒲贝酮、去氢浙贝母碱、鄂贝母碱、平贝酮、蒲贝碱B、蒲贝碱E、平贝母碱A、介藜芦碱和乌苏里贝母碱的生物合成中起积极作用，而 、 和 的下调可能导致浙贝宁水平降低。加权基因共表达网络分析表明， 、 和 与浙贝母碱和平贝母碱A呈负相关，而 和 呈正相关。 和 可能在贝母素和川贝母啶的生物合成中起负作用，而 起正作用。此外，高表达的C2H2、HSF、AP2/ERF、HB、GRAS、C3H、NAC、MYB相关转录因子（TFs）、GARP-G2样TFs和WRKY可能在浙贝母碱、贝母素、川贝母啶和平贝母碱A的积累中起积极作用。
这些结果为川贝母的科学采收提供了新的见解。
