Monoterpenes are typical aroma components of muscat grape ( L.) cultivars. However, differences in the molecular mechanism of monoterpene biosynthesis between Muscat and non-Muscat grapes remain unclear. Here, comprehensive transcriptomic and metabolomic analyses of two F1 hybrids with different aroma profiles obtained from crosses between 'Muscat Hamburg' and 'Red Globe' grapes were performed to examine the unique monoterpene accumulation pattern and related candidate genes. The concentrations of most monoterpenes differed at various times, in the hybrid progeny, increasing from the pre-veraison stage to the veraison stage, followed by a decreasing trend from veraison to maturity. Within the F1 generation, the concentrations of accumulated monoterpenes were significantly higher in Muscat grapes than in neutral grapes. Furthermore, linalool, α-terpineol, and l-α-terpineol may be important odorants affecting the floral characteristics of Muscat grapes due to their high odor activity values. Transcriptional analysis identified three (LOC100249323, LOC100268079, and LOC100247834), 1 (LOC100257071), one (LOC100251148), one (LOC100265082), and one (LOC100257234) genes encoding proteins involved in the MEP and MVA pathways. Eleven TPS genes potentially involved in monoterpene regulation were also identified. Among them, (LOC100853562) showed consistency with the accumulation of monoterpenes and had a high expression level; MYB (LOC100255488), GATA (LOC100262474), and ERF (LOC100255943, LOC100260401) were selected as candidate genes encoding transcription factors. The findings in this study provide new insights for further functional validation and investigation of genes related to monoterpene synthesis in Muscat aroma grapes.

中文翻译：

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麝香葡萄和中性葡萄杂交种单萜生物合成的代谢组学和转录组学分析


单萜是麝香葡萄（L.）品种的典型香气成分。然而，麝香葡萄和非麝香葡萄之间单萜生物合成分子机制的差异仍不清楚。在这里，对“汉堡麝香”和“红地球”葡萄杂交获得的两个具有不同香气特征的 F1 杂交种进行了全面的转录组学和代谢组学分析，以检查独特的单萜积累模式和相关候选基因。大多数单萜的浓度在不同时期存在差异，在杂种后代中，从转色前期到转色期呈增加趋势，从转色期至成熟期呈下降趋势。在F1代中，麝香葡萄中积累的单萜浓度显着高于中性葡萄。此外，芳樟醇、α-萜品醇和l-α-萜品醇由于其高气味活性值，可能是影响麝香葡萄花特性的重要气味剂。转录分析鉴定出 3 个（LOC100249323、LOC100268079 和 LOC100247834）、1 个（LOC100257071）、1 个（LOC100251148）、1 个（LOC100265082）和 1 个（LOC100257234）编码参与 MEP 和 MVA 途径的蛋白质的基因。还鉴定了 11 个可能参与单萜调节的 TPS 基因。其中(LOC100853562)与单萜的积累表现一致，且表达量较高；选择MYB（LOC100255488）、GATA（LOC100262474）和ERF（LOC100255943、LOC100260401）作为编码转录因子的候选基因。这项研究的结果为进一步功能验证和研究与麝香葡萄中单萜合成相关的基因提供了新的见解。