Cucurbitacins are extremely bitter compounds mainly present in Cucurbitaceae, where Luffa belongs. However, there is no comprehensive analysis of cucurbitacin biosynthesis in Luffa fruit. Therefore, this study analyzed bitter (WM709) and non-bitter (S1174) genotypes of Luffa to reveal the underlying mechanism of cucurbitacin biosynthesis by integrating metabolome and transcriptome analyses. A total of 422 metabolites were detected, including vitamins, essential amino acids, antioxidants, and antitumor substances. Of these, 131 metabolites showed significant differences between bitter (WM709) and non-bitter (S1174) Luffa fruits. The levels of isocucurbitacin B, cucurbitacin D, 23,24-dihydro cucurbitacin E, cucurbitacin F were significantly higher in bitter than in non-bitter Luffa. Transcriptome analysis showed that Bi, cytochromes P450s (CYP450s), and acyltransferase (ACT) of the cucurbitacin biosynthesis pathway, were significantly up-regulated. Moreover, drought stress and abscisic acid (ABA) activated genes of the cucurbitacin biosynthesis pathway. Furthermore, dual-luciferase reporter and yeast one-hybrid assays demonstrated that ABA-response element binding factor 1 (AREB1) binds to the Bi promoter to activate Bi expression. Comparative analysis of the Luffa and cucumber genomes showed that Bi, CYP450s, and ACT are located in the conserved syntenic loci, and formed a cucurbitacin biosynthesis cluster. This study provides important insights into major genes and metabolites of the cucurbitacin biosynthetic pathway, deepening the understanding of regulatory mechanisms of cucurbitacin biosynthesis in Luffa.

葫芦素是一种极苦的化合物，主要存在于葫芦科，其中丝瓜属于。然而，目前尚无对葫芦素生物合成的综合分析。丝瓜水果。因此，本研究分析了苦味 (WM709) 和无苦味 (S1174) 基因型丝瓜通过整合代谢组和转录组分析揭示葫芦素生物合成的潜在机制。共检测出422种代谢物，包括维生素、必需氨基酸、抗氧化剂和抗肿瘤物质。其中，131 种代谢物在苦味 (WM709) 和无苦味 (S1174) 之间表现出显着差异丝瓜水果。苦味中异葫芦素B、葫芦素D、23,24-二氢葫芦素E、葫芦素F的含量显着高于非苦味。丝瓜. 转录组分析表明双, 葫芦素生物合成途径的细胞色素 P450s (CYP450s) 和酰基转移酶 (ACT) 显着上调。此外，干旱胁迫和脱落酸 (ABA) 激活了葫芦素生物合成途径的基因。此外，双荧光素酶报告基因和酵母单杂交试验表明 ABA 反应元件结合因子 1 (AREB1) 与双启动子激活双表达。比较分析丝瓜黄瓜基因组表明双, CYP450 和行为位于保守的同线基因座上，形成葫芦素生物合成簇。该研究对葫芦素生物合成途径的主要基因和代谢物提供了重要的见解，加深了对葫芦素生物合成调控机制的理解。丝瓜.