Terpene aroma compounds are key quality attributes of postharvest Torreya grandis nuts, contributing to their commercial value. However, terpene biosynthesis and regulatory networks in different T. grandis cvs. are still poorly understood. Here, chief cvs. ‘Xi Fei’ and ‘Xiangya Fei’ were investigated for their differences in terpene biosynthesis and gene expression levels during postharvest ripening using headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography–mass spectrometry (GC-MS) and transcriptomic datasets. A total of 28 and 22 aroma compounds were identified in ‘Xi Fei’ and ‘Xiangya Fei’, respectively. Interestingly, differences in aroma composition between the two cvs. were mostly attributed to D-limonene and α-pinene levels as key determinants in Torreya nuts’ flavor. Further, transcriptome profiling, correlation analysis, and RT-qPCR annotated two novel genes, TgTPS1 in ‘Xi Fei’ and TgTPS2 in ‘Xiangya Fei’, involved in terpene biosynthesis. In addition, six transcription factors (TFs) with comparable expression patterns to TgTPS1 and four TFs to TgTPS2 were identified via correlation analysis of a volatile and transcriptome dataset to be involved in terpene biosynthesis. Our study provides novel insight into terpene biosynthesis and its regulation at the molecular level in T. grandis nut and presents a valuable reference for metabolic engineering and aroma improvement in this less explored nut.

Anthocyanins, an important class of flavonoids, determine the color quality of many horticultural crops and influence their postharvest quality. Their accumulation is controlled by the phenylpropanoid–flavonoid biosynthetic pathway and by post-synthetic modifications such as glycosylation, acylation, and methylation, which contribute to pigment chemical diversity and stability. To better understand and control anthocyanin beyond conventional breeding, increasing evidence indicates that epigenetic mechanisms, including DNA methylation, histone modifications, noncoding RNAs, and chromatin remodeling, regulate anthocyanin biosynthetic and regulatory genes and thereby influence the accumulation of anthocyanins. This review examines anthocyanin biosynthesis and the epigenetic regulation of anthocyanin accumulation in horticultural crops and discusses prospects for targeted quality improvement. We distinguish plant-level epigenetic evidence from downstream evidence on anthocyanin composition, postharvest stability, and bioavailability and identify current gaps in linking epigenetic marks to functional outcomes.