Identification of Co-Expressed Genes Related to Theacrine Synthesis in Tea Flowers at Different Developmental Stages

Genome-wide identification and functional analysis of CYP450 genes in eggplant (Solanum melongena L.) with a focus on anthocyanin accumlation

BACKGROUND

In plants, Cytochrome P450 (CYP450) constitutes the largest family of metabolic enzymes and plays a crucial role in various physiological processes, including plant growth and development. Eggplants are well-known for their peel's high concentration of anthocyanin compounds that provide significant health benefits to humans. The accumulation of anthocyanins in eggplant peels is an important process during growth and development. Therefore, it is essential to identify the CYP450 genes in eggplant (SmCYPs) and analyze their expression profiles during the period of anthocyanin accumulation in the peel.

RESULTS

A total of 180 SmCYPs were identified in the eggplant genome and classified into eight subfamilies based on phylogenetic analysis. These SmCYPs exhibited highly conserved gene structure (exon/intron) and protein motifs, especially within their respective subgroup. Sixteen pairs of genes with collinearity were identified through gene duplication analysis. Promoter cis-acting element analysis revealed that SmCYPs are involved in various responses, including growth and development, stress responsiveness, and light responsiveness. Transcriptome data analysis revealed that all SmCYPs were expressed in various eggplant tissues, such as roots, stems, leaves, flowers, and fruits; with diverse expression patterns among members. The expression patterns of SmCYPs in eggplant peel also exhibited diversity during different stages of anthocyanin accumulation. qRT-PCR analysis demonstrated similar expression patterns for 15 selected SmCYPs as observed in the transcriptome data. Metabolomics analysis further suggested that SmCYPs are involved in the biosynthesis of secondary metabolites and metabolic pathways related to flavonoid and flavone/flavonol biosynthesis. Notably, three specific SmCYPs (SmCYP73A1/75A/98A1) play a significant role in flavonoid biosynthesis, particularly in anthocyanin synthesis in eggplant.

CONCLUSION

Genome-wide identification, phylogenetic analysis, expression profile analysis, and exploration of metabolic pathways related to SmCYPs provide valuable insights into the roles of these genes in anthocyanin accumulation in various tissues and organs, including eggplant peel. The findings from this study lay a foundation for the functional analysis of SmCYPs involvement in anthocyanin accumulation in eggplant peel, providing a molecular basis for breeders to cultivate novel varieties of eggplants with high levels of anthocyanin content.

Molecular mechanism overview of metabolite biosynthesis in medicinal plants

Medicinal plants are essential and rich resources for plant-based medicines and new drugs. Increasing attentions are paid to the secondary metabolites of medicinal plants due to their unique biological activity, pharmacological action, and high utilization value. However, the development of medicinal plants is constrained by limited natural resources and an unclear understanding of the mechanisms underlying active medicinal ingredients, thereby rendering the utilization and exploration of secondary metabolites more challenging. Besides, with the advancement of research on biosynthesis and molecular metabolism of natural products from medicinal plants, the methods for studying the biological activity and pharmacological effects of these products are constantly evolving. In recent years, significant progress has been made in the biosynthetic pathways and related regulatory genes of secondary metabolites in medicinal plants, which has greatly advanced both basic research and the development of clinical applications for medicinal plants. In this review, we discuss the past two decades of international research on the development of medicinal plant resources, mainly focusing on the biosynthetic pathway of secondary metabolites, intracellular signal transduction processes, multi-omics applications, and the application of gene editing technology in related research progress. We also discuss future development trends to promote the deep mining and development of natural products from medicinal plants, providing a useful reference.

Production regions discrimination of Huangguanyin oolong tea by using the content of chemical components and rare earth elements

Oolong tea is one of the most popular tea beverages in China. Tea cultivars, processing technology and origin of production affect the quality and price of oolong teas. To investigate the differences in Huangguanyin oolong tea from different production regions, the chemical components, mineral elements and rare earth elements of Huangguanyin oolong tea produced in Yunxiao (YX) and Wuyishan (WY) were analyzed by using spectrophotometry methods, targeted metabolomics and inductive plasma coupled mass spectrometry (ICP-MS). The results of spectrophotometry methods revealed that there were significant differences in thearubigin, tea polyphenols and water extract between Huangguanyin oolong teas from different production regions. Targeted metabolomics identified a total of 31 chemical components in Huangguanyin oolong teas from the two production regions, of which 14 chemical components were significantly different and contributed to the regional differentiation of Huangguanyin oolong tea. Yunxiao Huangguanyin had relatively higher contents of (-)-Epigallocatechin-3-O-(3-O-methylgallate) (EGCG3″Me), ornithine (Orn) and histidine (His), while Wuyishan Huangguanyin had relatively higher contents of glutamic acid (Glu), γ-aminobutyric acid (GABA), β-aminobutyric acid (β-ABA) and other components. Moreover, ICP-MS identified a total of 15 mineral elements and 15 rare earth elements in Huangguanyin oolong tea from the two production regions, of which 15 elements were significantly different between YX and WY, and contributed to the regional differentiation of Huangguanyin oolong tea. K had a relatively higher content in Yunxiao Huangguanyin, while rare earth elements had relatively higher contents in Wuyishan Huangguanyin. The classification results by the production region showed that the discrimination rate of the support vector machine (SVM) model based on the 14 different chemical components reached 88.89%, while the SVM model based on the 15 elements reached 100%. Therefore, we used targeted metabolomics and ICP-MS techniques to screen and explore the chemical components, mineral elements and rare earth elements differences among two production regions, which indicated the feasibility of Huangguanyin oolong tea classification by production regions in the study. The results will provide some reference for the distinction between the two production regions of Huangguanyin oolong tea.

Allele-specific expression and chromatin accessibility contribute to heterosis in tea plants (Camellia sinensis)

Heterosis is extensively used to improve crop productivity, yet its allelic and chromatin regulation remains unclear. Based on our resolved genomes of the maternal TGY and paternal HD, we analyzed the contribution of allele-specific expression (ASE) and chromatin accessibility of JGY and HGY, the artificial hybrids of oolong tea with the largest cultivated area in China. The ASE genes (ASEGs) of tea hybrids with maternal-biased were mainly related to the energy and terpenoid metabolism pathways, whereas the ASEGs with paternal-biased tend to be enriched in glutathione metabolism, and these parental bias of hybrids may coordinate and lead to the acquisition of heterosis in more biological pathways. ATAC-seq results showed that hybrids have significantly higher accessible chromatin regions (ACRs) compared with their parents, which may confer broader and stronger transcriptional activity of genes in hybrids. The number of ACRs with significantly increased accessibility in hybrids was much greater than decreased, and the associated alleles were also affected by differential ACRs across different parents, suggesting enhanced positive chromatin regulation and potential genetic effects in hybrids. Core ASEGs of terpene and purine alkaloid metabolism pathways with significant positive heterosis have greater chromatin accessibility in hybrids, and were potentially regulated by several members of the MYB, DOF and TRB families. The binding motif of CsMYB85 in the promoter ACR of the rate-limiting enzyme CsDXS was verified by DAP-seq. These results suggest that higher numbers and more accessible ACRs in hybrids contribute to the regulation of ASEGs, thereby affecting the formation of heterotic metabolites.

Changes in Non-Volatile and Volatile Metabolites Associated with Heterosis in Tea Plants (Camellia sinensis)

Heterosis or hybrid vigor is extensively used in plant breeding. However, the contribution of metabolites to heterosis is still elusive. Here, we systematically identified the non-volatile and volatile metabolites of two hybrids and their parents in Camellia sinensis. The metabolomics analysis showed prevalent non-additive accumulation in hybrids, among which the non-additive nucleotides, alkaloids, organic acids, and tannins contribute to the positive heterosis of hybrids, including typical inosine, guanosine, adenosine, caffeine, succinic acid, adipic acid, xylonic acid, and gallic acid. The catechins and free amino acids in hybrids showed negative heterosis compared to its maternal cultivar TGY. Furthermore, the significant accumulation of non-additive terpenes combined with the mild heterosis of other types of volatiles contributes to the aroma of tea plant hybrids. The genetics of volatiles from different parents affect the aroma of hybrids processed into oolong tea. The comprehensive heterosis of these non-additive metabolites may play an important role in the formation of desirable breeding traits for hybrids. Our results provide insights into the utilization of heterosis breeding and the regulation of heterosis metabolites in tea plants.