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Background: Plants have evolved a panoply of specialized metabolites that increase their environmental fitness. Two examples are caffeine, a purine psychotropic alkaloid, and crocins, a group of glycosylated apocarotenoid pigments. Both classes of compounds are found in a handful of distantly related plant genera (Coffea, Camellia, Paullinia, and Ilex for caffeine; Crocus, Buddleja, and Gardenia for crocins) wherein they presumably evolved through convergent evolution. The closely related Coffea and Gardenia genera belong to the Rubiaceae family and synthesize, respectively, caffeine and crocins in their fruits. Results: Here, we report a chromosomal-level genome assembly of Gardenia jasminoides, a crocin-producing species, obtained using Oxford Nanopore sequencing and Hi-C technology. Through genomic and functional assays, we completely deciphered for the first time in any plant the dedicated pathway of crocin biosynthesis. Through comparative analyses with Coffea canephora and other eudicot genomes, we show that Coffea caffeine synthases and the first dedicated gene in the Gardenia crocin pathway, GjCCD4a, evolved through recent tandem gene duplications in the two different genera, respectively. In contrast, genes encoding later steps of the Gardenia crocin pathway, ALDH and UGT, evolved through more ancient gene duplications and were presumably recruited into the crocin biosynthetic pathway only after the evolution of the GjCCD4a gene.

Lonicera japonica is a wide-spread member of the Caprifoliaceae (honeysuckle) family utilized in traditional medical practices. This twining vine honeysuckle is also a much-sought ornamental, in part due to its dynamic flower coloration, which changes from white to gold during development.The molecular mechanism underlying dynamic flower coloration in L. japonica was elucidated by integrating whole genome sequencing, transcriptomic analysis, and biochemical assays.Here, we report a chromosome-level genome assembly of L. japonica, comprising nine pseudo-chromosomes with a total size of 843.2 Mb. We also provide evidence for a whole genome duplication event in the lineage leading to L. japonica, which occurred after its divergence from Dipsacales and Asterales. Moreover, gene expression analysis not only revealed correlated expression of the relevant biosynthetic genes with carotenoid accumulation, but also suggested a role for carotenoid degradation in L. japonica's dynamic flower coloration. The variation of flower color is consistent with not only the observed carotenoid accumulation pattern, but also with the release of volatile apocarotenoids that presumably serve as pollinator attractants.Beyond novel insights into the evolution and dynamics of flower coloration, the high-quality L. japonica genome sequence also provides a foundation for molecular breeding to improve desired characteristics.

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To find novel functional beverages from folk teas, 33 species of frequently used non-Camellia tea (plants other than Camellia) were collected and compared with Camellia tea (green tea, pu-erh tea and black tea) for the first time. Data are reported here on the quantities of 20 free amino acids (FAAs) and three purine alkaloids (measured by UHPLC), total polyphenols (measured by Folin-Ciocalteu assay), and antioxidant activity (DPPH). The total amounts of FAAs in non-Camellia tea (0.62–18.99 mg/g) are generally less than that of Camellia tea (16.55–24.99 mg/g). However, for certain FAAs, the quantities were much higher in some non-Camellia teas, such as γ-aminobutyric acid in teas from Ampelopsis grossedentata, Isodon serra and Hibiscus sabdariffa. Interestingly, theanine was detected in tea from Potentilla fruticosa (1.16±0.81 mg/g). Furthermore, the content of polyphenols in teas from A. grossedentata, Acer tataricum subsp. ginnala are significantly higher than those from Camellia tea; teas from I. serra, Pistacia chinensis and A. tataricum subsp. ginnala have remarkable antioxidant activities similar to the activities from green tea (44.23 μg/mL). Purine alkaloids (caffeine, theobromine and theophylline) were not detected in non-Camellia teas. The investigation suggest some non-Camellia teas may be great functional natural products with potential for prevention of chronic diseases and aging, by providing with abundant polyphenols, antioxidants and specific FAAs.

Scutellaria baicalensis ( S. baicalensis ) and Scutellaria barbata ( S. barbata ) are common medicinal plants of the Lamiaceae family. Both produce specific flavonoid compounds, including baicalein, scutellarein, norwogonin, and wogonin, as well as their glycosides, which exhibit antioxidant and antitumor activities. Here, we report chromosome-level genome assemblies of S. baicalensis and S. barbata with quantitative chromosomal variation (2 n = 18 and 2 n = 26, respectively). The divergence of S. baicalensis and S. barbata occurred far earlier than previously reported, and a whole-genome duplication (WGD) event was identified. The insertion of long terminal repeat elements after speciation might be responsible for the observed chromosomal expansion and rearrangement. Comparative genome analysis of the congeneric species revealed the species-specific evolution of chrysin and apigenin biosynthetic genes, such as the S. baicalensis -specific tandem duplication of genes encoding phenylalanine ammonia lyase and chalcone synthase, and the S. barbata -specific duplication of genes encoding 4-CoA ligase. In addition, the paralogous duplication, colinearity, and expression diversity of CYP82D subfamily members revealed the functional divergence of genes encoding flavone hydroxylase between S. baicalensis and S. barbata . Analyzing these Scutellaria genomes reveals the common and species-specific evolution of flavone biosynthetic genes. Thus, these findings would facilitate the development of molecular breeding and studies of biosynthesis and regulation of bioactive compounds.

NotePaeonia suffruticosa ANDR. (Paeoniaceae) is found extensively in China. It is an important Chinese medicinal plant from the section Moutan of the genus Paeonia. This genus consists of ca. 35 species placed in three sections: Moutan, Oneapia, and Paeonia.1) The root cortex of this plant (Chinese name: mudanpi) is a well-known Chinese herbal medicine widely used as an analgesic, anaphylactic, antioxidative, and antiinflammatory agent. Numerous studies on the chemistry and pharmacology of this species have been performed.2) Previous phytochemical studies indicated that stilbenes were the primary bioactivity constituents of peony seeds. These stilbenes exhibit potent biological activities such as cytotoxic, antimutagenic, ecdysteroid antagonist, antioxidant, hyperpigmentation, antitumor, and anti-inflammatory activity and can improve bone disease. [3][4][5][6][7][8] In the course of searching for new bioactive natural products from the seeds of this plant, 11 stilbenes, trans-(1) and cis-suffruticosol D (2), trans-resveratrol (3), 9) trans-e-viniferin (4), 7)cis-e-viniferin (5), 7) gnetin H (6), 7) cis-gnetin H (7), suffruticosol A (8),3) suffruticosol B (9), 3) suffruticosol C (10), 3) and cis-ampelopsin E (11), 10) were isolated from the ethyl acetate extract of the seeds of P. suffruticosa. Among them, 1, 2, and 7 were new compounds. Here, we report the isolation and extensive structural elucidation of the new compounds. Results and Discussiontrans-Suffruticosol D (1) Three new oligostilbenes, trans-suffruticosol D (1), cis-suffruticosol D (2), and cis-gnetin H (7), were isolated along with the eight known stilbenes, trans-resveratrol (3), trans-e e-viniferin (4), cis-e e-viniferin (5), gnetin H (6), suffruticosol A (8), suffruticosol B (9), suffruticosol C (10), and cis-ampelopsin E (11) from the seeds of Paeonia suffruticosa. Compounds 3-6 were isolated for the first time from this plant species, and compound 11 was isolated for the first time from the genus Paeonia. The structures of the new compounds were elucidated based on spectral analyses, including 1D and 2D NMR experiments. The absolute configuration of compound 1 was determined by quantum chemical calculation of the electronic circular dichroism and comparison with the experimental circular dichroism spectrum.