BACKGROUND: Terpenes are important components of plant aromas, and terpene synthases (TPSs) are the key enzymes driving terpene diversification. In this study, we characterized the volatile terpenes in five different Chrysanthemum nankingense tissues. In addition, genome-wide identification and expression analysis of TPS genes was conducted utilizing an improved chromosome-scale genome assembly and tissue-specific transcriptomes. The biochemical functions of three representative TPSs were also investigated.
RESULTS: We identified tissue-specific volatile organic compound (VOC) and volatile terpene profiles. The improved Chrysanthemum nankingense genome assembly was high-quality, including a larger assembled size (3.26 Gb) and a better contig N50 length (3.18 Mb) compared to the old version. A total of 140 CnTPS genes were identified, with the majority representing the TPS-a and TPS-b subfamilies. The chromosomal distribution of these TPS genes was uneven, and 26 genes were included in biosynthetic gene clusters. Closely-related Chrysanthemum taxa were also found to contain diverse TPS genes, and the expression profiles of most CnTPSs were tissue-specific. The three investigated CnTPS enzymes exhibited versatile activities, suggesting multifunctionality.
CONCLUSIONS: We systematically characterized the structure and diversity of TPS genes across the Chrysanthemum nankingense genome, as well as the potential biochemical functions of representative genes. Our results provide a basis for future studies of terpene biosynthesis in chrysanthemums, as well as for the breeding of improved chrysanthemum varieties.

UNASSIGNED: Trehalose is vital for plant metabolism, growth, and stress resilience, relying on Trehalose-6-phosphate synthase (TPS) and Trehalose-6-phosphate phosphatase (TPP) genes. Research on these genes in cultivated peanuts (Arachis hypogaea) is limited.
UNASSIGNED: This study employed bioinformatics to identify and analyze AhTPS and AhTPP genes in cultivated peanuts, with subsequent experimental validation of AhTPS9\'s role in cold tolerance.
UNASSIGNED: In the cultivated peanut genome, a total of 16 AhTPS and 17 AhTPP genes were identified. AhTPS and AhTPP genes were observed in phylogenetic analysis, closely related to wild diploid peanuts, respectively. The evolutionary patterns of AhTPS and AhTPP genes were predominantly characterized by gene segmental duplication events and robust purifying selection. A variety of hormone-responsive and stress-related cis-elements were unveiled in our analysis of cis-regulatory elements. Distinct expression patterns of AhTPS and AhTPP genes across different peanut tissues, developmental stages, and treatments were revealed, suggesting potential roles in growth, development, and stress responses. Under low-temperature stress, qPCR results showcased upregulation in AhTPS genes (AhTPS2-5, AhTPS9-12, AhTPS14, AhTPS15) and AhTPP genes (AhTPP1, AhTPP6, AhTPP11, AhTPP13). Furthermore, AhTPS9, exhibiting the most significant expression difference under cold stress, was obviously induced by cold stress in cultivated peanut, and AhTPS9-overexpression improved the cold tolerance of Arabidopsis by protect the photosynthetic system of plants, and regulates sugar-related metabolites and genes.
UNASSIGNED: This comprehensive study lays the groundwork for understanding the roles of AhTPS and AhTPP gene families in trehalose regulation within cultivated peanuts and provides valuable insights into the mechanisms related to cold stress tolerance.

Most volatile sesquiterpenes had been purified from plants using distillation and preparative gas chromatography, which is not applicable to many laboratories that do not possess a needed facility. Thus, this review focuses on a modern purification method for volatile sesquiterpenes using Escherichia coli cells that functionally express terpene synthase (Tps) genes. It was recently developed that recombinant E. coli cells carrying Tps genes were cultured in two-layer media (n-octane/TB medium) without harming the cells, and the volatile hydrophobic compounds trapped in the n-octane were purified by two-phase partition (alkane/alkaline 50% MeOH), silica gel column chromatography, and reversed-phase preparative high-performance liquid chromatography (if necessary). Consequently, it was found that the volatile sesquiterpenes are easily purified, the structures of which can then be determined by nuclear magnetic resonance, [α]D and gas chromatography-mass spectrometry analyses. The antioxidant activities of several volatile sesquiterpenes are also presented in this review.

A simple method to purify volatile sesquiterpenes from recombinant Escherichia coli was developed using the cells that carried known sesquiterpene synthase (Tps) genes ZzZss2 (ZSS2) and ZoTps1. This method was applied for the purification and structural analyses of volatile sesquiterpenes produced by E. coli cells that carried unidentified Tps genes, which were isolated from the Aralia-genus edible plants belonging to the family Araliaceae. Recombinant cells carrying each Tps gene were cultured in the two-layer medium (n-octane/TB medium), and volatile sesquiterpenes trapped in n-octane were purified through two-phase partition, silica gel column chromatography, and reversed-phase preparative high-performance liquid chromatography, if necessary. Further, their structures were confirmed by nuclear magnetic resonance, [α]D, and gas chromatography-mass spectrometry analyses. Herein, the products of E. coli cells that carried two Tps gene (named AcTps1 and AcTps2) in Araria cordata \"Udo\" and a Tps gene (named AeTps1) in Aralia elata \"Taranoki\" were studied resulting in identifying functionalities of these cryptic Tps genes.