Celery (Apium graveolens L.) seeds have a unique aroma and can be used in the pharmaceutical industry. Terpenoids are the main volatile organic compounds (VOCs) of celery seed essential oil, and phthalides are the source of its aroma. However, thus far, no studies have been conducted on the metabolism of terpenoids and phthalides in celery. In this study, 195 VOCs were detected in celery seeds by using headspace injection combined with gas chromatography–mass spectrometry (GC–MS). The content of 85 VOCs, including 20 terpenoids and 6 phthalides, was found to be significantly different during the five stages of celery seed development. Based on the pattern of changes in the concentrations of terpenoids and phthalides, an integrated transcriptome and metabolome analysis of three developmental celery seed stages was performed. The results showed that 11 differentially expressed structural genes involved in the metabolism of terpenoids have a positive correlation coefficient with 16 terpenoids, while 103 differentially expressed transcription factor genes are correlated with these 11 differentially expressed genes (DEGs). Among these differentially expressed transcription factor genes, two basic helix-loop-helix (bHLH) genes are similar with Arabidopsis thaliana bHLH gene (MYC2), which has already known to be involved in the regulation of terpenoid metabolism. The results of the integrated analysis also revealed that 88 differentially expressed transcription factor genes are related to 6 phthalides, and one myeloblastosis (MYB) gene is similar with petunia MYB gene (ODORANT1), which is involved in the regulation of the metabolism of volatile benzene compounds in petunia (Pharbitis nil) flowers. Therefore, this study has laid a foundation for further research related to the identification of key genes that regulate the metabolism of terpenoids and phthalides in celery. Moreover, these results can contribute significantly to the improvement in the quality of celery seed essential oil.

芹菜（芹菜L.) 种子具有独特的香气，可用于制药工业。萜类化合物是芹菜籽精油的主要挥发性有机化合物（VOCs），苯酞是其香气的来源。然而，迄今为止，尚未对芹菜中萜类化合物和苯酞的代谢进行研究。在本研究中，通过顶空进样结合气相色谱-质谱联用 (GC-MS)，在芹菜种子中检测到 195 种 VOC。发现在芹菜种子发育的五个阶段中，85 种 VOCs 的含量存在显着差异，其中包括 20 种萜类化合物和 6 种苯酞。基于萜类化合物和苯酞浓度的变化模式，对芹菜种子的三个发育阶段进行了综合转录组和代谢组分析。结果表明，参与萜类化合物代谢的11个差异表达结构基因与16个萜类化合物具有正相关系数，而103个差异表达转录因子基因与这11个差异表达基因（DEGs）相关。在这些差异表达的转录因子基因中，有两个基本的螺旋-环-螺旋（bHLH ) 基因与拟南芥 bHLH基因 ( MYC2 )相似，后者已知参与萜类代谢的调节。综合分析结果还显示，88个差异表达转录因子基因与6种苯酞相关，1个成髓细胞（MYB）基因与牵牛花MYB基因（ODORANT1）相似，参与挥发性苯代谢的调控。矮牵牛中的化合物（Pharbitis nil） 花卉。因此，本研究为进一步研究鉴定调控芹菜中萜类化合物和苯酞类代谢的关键基因奠定了基础。此外，这些结果可以显着提高芹菜籽精油的质量。