Transcriptomics and Metabolomics Reveal the Critical Genes of Carotenoid Biosynthesis and Color Formation of Goji (Lycium barbarum L.) Fruit Ripening

Integrated metabolome and transcriptome analyses revealed key cytochrome P450 genes involved in the biosynthesis of oleanane-type saponins in Hedera helix L

Hedera helix L. is a traditional Chinese medicinal and industrial crop commonly used to treat coughs and upper respiratory tract diseases. Additionally, it can be utilized as insecticidal, mosquito repellent and biopesticide. Its primary components are pentacyclic triterpenoid saponins include oleanolic acid, hederagenin, hederacoside C, etc. Currently, cytochrome P450 (CYP450) has been shown to be closely associated with the structural diversification and functional modification of the triterpenoid. However, the research on H. helix is still shallow, especially the functional characterization of CYP450 gene in the stage of modifying pentacyclic triterpenoid skeleton. This study integrated analyzed transcriptome and the accumulation modes of the main metabolites of H. helix and screened six CYP450 candidate genes. RT-qPCR results showed that candidate genes exhibited tissue specificity and inducible expression specificity. Based on in vitro and in vivo validation, both HhCYP716A409 and HhCYP716S11 showed activity of oxidase in β-amyrin C-28, producing oleanolic acid by participating in the C-28 oxidization of β-amyrin. HhCYP72D57, HhCYP72A1140, and HhCYP72A1141 produced hederagenin by participating in the hydroxylation of oleanolic acid C-23. Additionally, HhCYP72D57, HhCYP72A1139, and HhCYP72A1141 were also involved in the hydroxylation of hederagenin C-16 to produce 16-OH hederagenin. This study confirms the pivotal roles of CYP716 and CYP72 families in oleanane-type triterpenoid biosynthesis and establishes a method to efficiently produce hederacoside C and derivatives, providing a genetic toolkit for metabolic engineering of H. helix to scale saponin production for pharmaceuticals, agrochemicals, or synthetic biology-driven design of novel triterpenoid biopesticides.

A review of Lycium barbarum polysaccharides: Extraction, purification, structural-property relationships, and bioactive molecular mechanisms

Lycium barbarum L. is of great significance medicinal and edible plant, which is native to N. & Central China. The extensive health benefits of L. barbarum have earned it great respect in traditional medicine for centuries. Lycium barbarum polysaccharides (LBPs) being recognized as one of the most crucial bioactive compounds found within this plant, with it exhibit a diverse range of pharmacological activities and nutritional functions, thereby generating substantial market demand and broad application prospects. To gain a more comprehensive understanding of LBPs, the review discussed the extraction, purification and structural-property relationships of these compounds. In addition, this review provides a comprehensive summary of the potential mechanisms underlying various biological activities attributed to LBPs, including immune modulation, antioxidant effects, neuroprotection, hepatoprotection, and antitumor properties. The application status and the future research directions of LBPs were subsequently presented. This review will establish a robust foundation and serve as an invaluable resource for future research and advancements in the field of LBPs.

Integrated Metabolomic and Transcriptomic Profiles Provide Insights into the Mechanisms of Anthocyanin and Carotenoid Biosynthesis in Petals of Medicago sativa ssp. sativa and Medicago sativa ssp. falcata

The petals of Medicago sativa ssp. sativa and M. sativa ssp. falcata are purple and yellow, respectively. Free hybridization between M. sativa ssp. sativa and M. sativa ssp. falcata has created hybrids with various flower colors in nature. Moreover, the flower colors of alfalfa are closely correlated with yield, nutritional quality, stress tolerance and other agronomic characteristics. To elucidate the underlying mechanisms of flower color formation in M. sativa ssp. sativa and M. sativa ssp. falcata, we conducted an integrative analysis of the transcriptome and metabolome of alfalfa with three different petal colors (purple, yellow and cream). The metabolic profiles suggested that anthocyanins and carotenoids are the crucial pigments in purple and yellow flowers, respectively. A quantitative exploration of the anthocyanin and carotenoid components indicated that the accumulations of cyanidin, delphinidin, peonidin, malvidin, pelargonidin and petunidin derivatives are significantly higher in purple flowers than in cream flowers. In addition, the content of carotenes (phytoene, α-carotene and β-carotene) and xanthophylls (α-cryptoxanthin, lutein, β-cryptoxanthin, zeaxanthin, antheraxanthin and violaxanthin derivatives) was markedly higher in yellow flowers than in cream flowers. Furthermore, we found that delphinidin-3,5-O-diglucoside and lutein were the predominant pigments accumulated in purple and yellow flowers, respectively. The transcriptomic results revealed that twenty-five upregulated structural genes (one C4H, three 4CL, twelve CHS, two CHI, one F3H, one F3'H, one F3'5'H and four DFR) are involved in the accumulation of anthocyanins in purple flowers, and nine structural genes (two PSY, one ZDS, two CRTISO, two BCH, one ZEP and one ECH) exert an effect on the carotenoid biosynthesis pathway in yellow flowers. The findings of this study reveal the underlying mechanisms of anthocyanin and carotenoid biosynthesis in alfalfa with three classic flower colors.

Combined Transcriptomics and Metabolomics Analysis Reveals the Effect of Selenium Fertilization on Lycium barbarum Fruit

As a beneficial nutrient and essential trace element, selenium plays a significant role in plant growth functions and human protein biosynthesis. Plant selenium enrichment is mainly obtained from both natural soil and exogenous selenium supplementation, while human beings consume selenium-enriched foods for the purposes of selenium supplementation. In this study, different types of selenium fertilizers were sprayed onto Lycium barbarum in Ningxia, and transcriptomics and metabolomics techniques were used to explore the effects of selenium on the fruit differentials and differential genes in Lycium barbarum. Taking the "Ning Qiyi No.1" wolfberry as the research object, sodium selenite, nano-selenium, and organic selenium were sprayed at a concentration of 100 mg·L-1 three times from the first fruiting period to the harvesting period, with a control treatment comprising the spraying of clear water. We determined the major metabolites and differential genes of the amino acids and derivatives, flavonoids, and alkaloids in ripe wolfberries. We found that spraying selenium significantly enhanced the Lycium barbarum metabolic differentiators; the most effective spray was the organic selenium, with 129 major metabolic differentiators and 10 common metabolic pathways screened after spraying. Nano-selenium was the next best fertilizer we screened, with 111 major metabolic differentiators, the same number as organic selenium in terms of differential genes and common metabolite pathways. Sodium selenite was the least effective of the three, with only 59 of its major metabolic differentials screened, but its differential genes and metabolites were enriched for five common pathways.