目的 分析干旱胁迫下忍冬Lonicera japonica全基因组DNA甲基化水平变化、模式以及与基因表达的关系，为进一步探究忍冬响应干旱胁迫的分子机制奠定基础。方法 采用全基因组重亚硫酸盐甲基化测序法（whole-genome bisulfite sequencing，WGBS），测定干旱胁迫下忍冬全基因组DNA甲基化水平，并联合转录组测序结果对差异甲基化基因相关的差异表达基因进行分析。结果 干旱胁迫下忍冬整体甲基化水平普遍上升；其中CG类型甲基化水平明显高于CHG或CHH甲基化类型；对不同干旱胁迫处理下的忍冬进行差异甲基化区域（differentially methylated regions，DMR）分析，发现1935、2158和1750个差异甲基化相关基因，基因组百科全书（Kyoto encyclopedia of genes and genomes，KEGG）富集分析表明，显著富集的通路主要包括亚油酸代谢，氮代谢通路和次生代谢物的生物合成通路等。通过转录组测序技术，发现差异甲基化基因相关的差异表达基因主要富集于次生代谢产物合成相关通路，同时筛选出4个在干旱胁迫下基因表达量上升显著的忍冬MYB（Lonicera japonica MYB，LjMYB）LjMYB转录因子。结论 干旱胁迫下忍冬甲基化水平上升，推测DNA甲基化调控基因表达是干旱影响金银花有效成分生物合成的作用机制之一。

Objective To analyze the changes and patterns of genome-wide DNA methylation level and its relationship with gene expression in Lonicera japonica under drought stress, and lay a foundation for further exploring the molecular mechanism of L. japonica in response to drought stress. Methods The whole-genome bisulfite sequencing (WGBS) was used to determine the DNA methylation level of L. japonica under drought stress, and the differentially expressed genes related to differentially methylated genes were analyzed in combination with transcriptome sequencing results. Results The overall methylation level of L. japonica under drought stress generally increased; The methylation level of CG type was significantly higher than that of CHG or CHH type. Differentially methylated regions (DMR) analysis of L. japonica under different drought stress treatments revealed 1935, 2158 and 1750 differentially methylated genes. Kyoto encyclopedia of genes and genomes (KEGG) enrichment analysis showed that the significantly enriched pathways included linoleic acid metabolism, nitrogen metabolism and biosynthesis of secondary metabolites. Through transcriptome sequencing technology, it was found that differentially expressed genes related to differentially methylated genes were mainly enriched in secondary metabolite synthesis-related pathways, and four LjMYB transcription factors with significant increase in gene expression under drought stress were screened. Conclusion Under drought stress, the methylation level of L. japonica increased, suggesting that DNA methylation regulation of gene expression is one of the mechanisms of drought affecting the biosynthesis of effective components of L. japonica.

R286.12

山东省重点研发计划（乡村振兴科技创新提振行动计划）项目（2022TZXD0036）；山东省农业良种工程项目（2021LZGC008）；山东省现代农业产业技术体系中草药创新团队项目（SDAIT-20）