目的 发掘植物激素信号通路中与北柴胡Bupleurum chinense侧根发育紧密关联的基因。方法 以自组拼接的北柴胡基因组为模板，对北柴胡推广品种川北柴1号苗期根系进行有参考基因组的转录组分析，筛选参与植物激素信号转导的关键基因，利用实时荧光定量聚合酶链式反应（real-time fluorescent quantitative polymerase chain reaction，qRT-PCR）技术验证关键基因对外源生长素处理的表达应答。结果 有参转录组分析得到32 259个基因，681个基因在有侧根成熟区（RO）样本中特异表达。加权基因共表达网络分析将基因分为56个模块，2个模块与主根长度和侧根数目显著相关。与侧根形成高度相关的生长素信号转导与运输通路上共发掘到88个差异基因，其中26个基因表达模式高度相关。转录组差异基因表达相关性与外源生长素处理后的基因表达结果联合分析表明，BcIAA13、BcARF19、BcSAUR55和BcSAUR72基因可能是侧根生长发育的关键基因。结论 进一步揭示了在RO样本中表达量高的基因可能与侧根发育密切相关，并筛选到转录因子BcARF19与BcIAA13密切相关，其可能调控下游基因的表达，进而影响侧根的生长发育。

Objective To explore key genes closely associated with lateral roots development of Bupleurum chinense in the plant signal transduction pathways.Methods Utilizing the self-assembled chromosome-level genome of B. chinense var. CC2 as a template, a transcriptome analysis was carried out on the root tissues at the seedling stage of B. chinense var. CBC1 respectively. The effects of exogenous IAA on the lateral root development and expression of differentially expressed genes in B. chinense seedlings were examined. Results The reference-based transcriptome analysis identified 32 259 genes, of which 681 were specifically expressed in the mature zone RO samples with lateral roots. Weighted gene co-expression network analysis divided the genes into 56 modules, with 2 modules significantly correlated with primary root length and lateral root number. A total of 88 differential genes were discovered in the auxin signal transduction and transport pathways that were highly related to the formation of lateral roots, among which 26 genes had highly correlated expression patterns. The combined analysis of the correlation of the expression of transcriptome differential genes and the gene expression results after exogenous auxin treatment indicated that the genes BcIAA13, BcARF19, BcSAUR55 and BcSAUR72 might be the key genes for the growth and development of lateral roots. Conclusion This study further revealed the genes highly expressed in the RO samples are closely related to the development of lateral roots. The transcription factor BcARF19, which was closely associated with BcIAA13, might regulate the expression of downstream genes and thus influence the growth and development of lateral roots.

R286.12

四川省国际合作项目（2023YFH0044，2023YFH0018）；国家现代农业产业技术体系项目（CARS-21）；西南科技大学博士基金项目（19ZX7117，21ZX7116）；西藏自治区重点研发（XZ202401ZY0020）