Summary: Lonicera macranthoides (LM) and L. japonica (LJ) are medicinal plants widely used in treating viral diseases, such as COVID‐19. Although the two species are morphologically similar, their secondary metabolite profiles are significantly different. Here, metabolomics analysis showed that LM contained ~86.01 mg/g hederagenin‐based saponins, 2000‐fold higher than LJ. To gain molecular insights into its secondary metabolite production, a chromosome‐level genome of LM was constructed, comprising 9 pseudo‐chromosomes with 40 097 protein‐encoding genes. Genome evolution analysis showed that LM and LJ were diverged 1.30–2.27 million years ago (MYA). The two plant species experienced a common whole‐genome duplication event that occurred ∼53.9–55.2 MYA before speciation. Genes involved in hederagenin‐based saponin biosynthesis were arranged in clusters on the chromosomes of LM and they were more highly expressed in LM than in LJ. Among them, oleanolic acid synthase (OAS) and UDP‐glycosyltransferase 73 (UGT73) families were much more highly expressed in LM than in LJ. Specifically, LmOAS1 was identified to effectively catalyse the C‐28 oxidation of β‐Amyrin to form oleanolic acid, the precursor of hederagenin‐based saponin. LmUGT73P1 was identified to catalyse cauloside A to produce α‐hederin. We further identified the key amino acid residues of LmOAS1 and LmUGT73P1 for their enzymatic activities. Additionally, comparing with collinear genes in LJ, LmOAS1 and LmUGT73P1 had an interesting phenomenon of ‘neighbourhood replication’ in LM genome. Collectively, the genomic resource and candidate genes reported here set the foundation to fully reveal the genome evolution of the Lonicera genus and hederagenin‐based saponin biosynthetic pathway.

Aside from its multiple medicinal uses, the fruit of Xylopia aethiopica is widely used in Africa as food. Herein, we characterize the protein profiles, mineral content and bioactive phytochemical composition of the seeds of this plant sourced in Ghana and Nigeria. Using label-free proteomics, a total of 677 proteins were identified, with 260 found in the Ghana-sourced samples while 608 proteins were detected in the samples from Nigeria. However, 114 proteins were common between the samples from the two countries, among which 48 were significantly changed. Bioinformatics and functional analyses revealed that the differential levels of the proteins were mainly linked to pathways involved amino acids metabolism and biosynthesis. The significantly changed proteins related mainly to catalytic activity and carbon metabolism. The samples from Nigeria also exhibited superior qualities in terms of their antioxidant effects, and total phenolic and flavonoid content. Finally, only the content of Na varied to a statistically significant level. This study lends support to its culinary use and hints towards the impact of location of cultivation on the quality of the seeds. There is however need for further mechanistic investigations to unravel the underlying reasons for the observed differences.

Ginkgolides are secondary metabolites unique to Ginkgo biloba with the potential to prevent and treat cardiovascular and cerebrovascular diseases. Although the biosynthetic pathways of ginkgolides have been partly uncovered, the mechanism regulating their biosynthesis is still largely unknown. Here, using multiomic and genetic analyses, we report the identification of a transcription factor, named ETHYLENE RESPONSE FACTOR ASSOCIATED WITH GINKGOLIDE BIOSYNTHESIS (GbEAG), as a critical regulator of ginkgolide biosynthesis. GbEAG is highly expressed in the roots of G. biloba, and its expression is significantly induced by methyl jasmonate (MeJA). Ginkgolide content was significantly increased in roots by overexpressing GbEAG using a “cut-dip-regeneration” system. GbEAG positively regulates ginkgolide biosynthesis by directly binding to the GCC-boxes in the promoter regions of genes involved in the biosynthesis of ginkgolides, such as ISOPENTENYL DIPHOSPHATE ISOMERASE ( GbIDI ) and CYTOCHROME P450 7005C3 ( GbCYP7005C3 ). GbEAG mediates the jasmonic acid (JA)-activated ginkgolide synthesis through its direct interaction with the JASMONATE ZINC-FINGER INFLORESCENCE MERISTEM DOMAIN 3 (GbJAZ3) repressor. Importantly, we also found that the central light-response regulator ELONGATED HYPOCOTYL 5 (GbHY5) mediates light induction of ginkgolide biosynthesis by binding to the G-box in the GbEAG promoter. Our findings provide mechanistic insights into the coordinated regulation of ginkgolide biosynthesis via JA and light signals, with GbEAG as a central regulator in G. biloba, and shed light on the potential to develop ginkgolide-rich varieties through molecular breeding and gene editing.