Collecting plant specimens
In the present study, 10 accessions assigned to 4 genera Atalantia, Luvunga, Paramignya, and Severinia were collected from different sites in Khanh Hoa and Lam Dong provinces of Vietnam (Fig. 1). Of these, six accessions of P. trimera (Oliv.) Burkill were collected at different sites in Khanh Hoa provinces including Ninh Van (PT1.NV, PT2.NV), Ninh Hoa (PT1.NH, PT2.NH), Dien Khanh (PT1.DK, PT2.DK); 1 accession of A. buxifolia (Poir.) Oliv. ex Benth collected in Van Ninh (PA.VN); 1 accession of S. monophylla (Lour.) Tanaka collected in Don Duong, Lam Dong province (PC.DD); two accessions of L. scandens (Roxb.), Wight, collected in Di Linh (PR.DL) and Cat Tien (PR.CT) in Lam Dong province (Fig. 1). The list of the collected accessions and information was summarized in Table 1.
Map of the sampling sites. Accessions of species P. trimera (Oliv.) Burkill, A. buxifolia (Poir.) Oliv. ex Benth, S. monophylla (Lour.) Tanaka, and L. scandens (Roxb.), Wight were collected at sites displayed as circles in the map. The map was created by using ArcGIS 10.3 using the color rendering and grouping tools built-in and Paintbrush version 2.5 (20190914) on mac OS Catalina.
Taxonomic treatment
P. trimera (Oliv.) Burkill distributes in the high land areas in Khanh Hoa, Lam Dong provinces of Vietnam. P. trimera is scrambling shrub or erect, long, and curved spines, non-hairy stem. Leaves simple, typical narrow oblong, lamina 1.0–1.5 cm wide, 5–12 cm long; short petiole 0.5 cm long, leaf sub-vein 8–10 pairs; inflorescences axillary, fasciculate, peduncle 3–4 mm long, separate; calyx 3 lobes, 4 mm long; corolla 3; stamens 5, separate; ovaries 3, only 1 ovule, 2 locules in the ovary; globose fruit, 1.5–2.5 cm in diameter, 2 seeded. flowering time from May-Aug., fruiting Sep-Dec. Roots, leaves and stems were used as traditional medicine to treat liver diseases and cancers (Figs. 2, 4a).
The typical morphology and anatomy of Paramignya trimera (Oliv.) Burkill. Woody shrub 1–4 m or above (a); A flowering tree (b); Typical trimerous flowers (c); Green fruits (d); Ripen fruits (d); Opened ripen fruit with two seeds encapsulated by mucus endocarp (e).
A. buxifolia (Poir.) Oliv. ex Benth distributed mainly in Van Ninh (Khanh Hoa) with several local names such as “Xao cua ga” or “Quyt gai” are medium climbing shrubs, up to 3 m tall; branches grayish brown, branchlets green; spikes axillary 0.5–1.2 cm or sometimes unarmed, apex yellowish; leaves simple, 2.5–3.5 cm wide, 3.5–4.5 mm long, petiole 4–8 mm, leaf blade ovate, obovate, elliptic, glabrous, coriaceous, midvein slightly ridged, apex rounded to obtuse at tip; inflorescences axillary, 1 to several flowers. Flowers 5 merous, petals white, 3–4 mm, stamens 10, calyx persistent. Fruit bluish black when ripe, globose, slightly oblate, or subellipsoid, 7–10 mm in diam., smooth, 1 or 2 seeded. Flowering from May-Aug., fruiting Sep-Dec. Roots, leaves and stems were used as traditional medicine to treat cough, lung diseases and kidney disorders (Fig. 4b).
S. monophylla (Lour.) Tanaka found in Don Duong (Lam Dong) was thorny shrub or small tree; spikes axillary 1–1.5 cm; leaves simple, ovate, apex round or retuse at tip, coriaceous, glabrous, round at base, short petiole; Inflorescences 4–6-flowered; calyx ca. 3.5–5 mm long; petals 4, petals white, oblong, obtuse, glabrous, stamens 8–10; filaments ca. 12 mm long, glabrous; anthers ca. 5 mm long, linear; ovary ca. 2.5 × 1.5 mm, long-ovoid, glabrous, 3-locular; style ca. 7 mm long, continuous with ovary, cylindric, glandular, glabrous; stigma capitate ca. 2.5 mm broad, glandular. Fruits yellow to orange, globose 1.5–2.0 cm in diameter, 1–2 seeded; flowering time from May-Aug., fruiting Sep-Dec. This species was used effectively for cough, expectorant, fever, anti-inflammatory, sciatica treatment and prevent aging of skin cells, roots and leaves used for skin disease, burning leaves to kill mosquitoes and insects (Fig. 2c).
L. scandens (Roxb.), Wight was discovered in Lam Dong of Vietnam with the local name “Xao leo”. L. scandens is woody climber or scrambling shrub; rough tufted from the ground with strong axillary sharp straight or slightly recurved spines. Leaves compound, digitately trifoliate or bifoliolate or simple; petioles 2–6 cm long, glabrous; lamina ca. 6.0–18.0 × 2.5–4.0 cm, variable, oblong-elliptic or oblanceolate, cuneate at base, shortly acuminate at apex, coriaceous, glabrous; secondary nerves 15 pairs; branches brown puberulent. No information from flowering time has been described. According to traditional experience, this plant is used to treat rheumatism, liver disease and ascites (Fig. 2d).
Phylogenetic relation analysis
The phylogenetic tree from ITS sequences included 3 groups (Fig. 5a). The first monophyletic group was only S. monophylla (PC.DD) as an out group. The second monophyletic group included 2 accessions of L. scandens (PR.DL and PR.CT). The third group was paraphyletic group with 9 accessions clustered in 2 sub-groups. The first sub-group included only P. trimera, whereas the second sub-group included 3 accessions P. trimera nested with P. confertifolia and A. buxifolia. In addition, in the second sub-group, the accessions of P. trimera collected in Dien Khanh, Vietnam (PT1.DK) and P. confertifolia from Mensong, China were in the same monophyletic clade whereas A. buxifolia (PA.VN) was clearly separated from others.
The unrooted tree from matK sequences included 3 groups in which the first monophyletic group were 2 species P. lobata and P. scandens (Australia), the second monophyletic group included only P. confertifolia (China) and the third group (paraphyletic group) included 3 sub-groups (Fig. 5b). The first sub-group included all accessions of P. trimera, the second sub-group included only S. monophylla and the third sub-group included L. scandens and A. buxifolia.
The unrooted tree from rbcL sequences included 2 main groups in which the first group included 3 species P. scandens, P. monophylla and P. lobata (Australia) and the second group (paraphilic group) included 5 species P. trimera, P. confertifolia (China), S. monophylla (Japan), A. buxifolia, and L. scandens (Fig. 5c). In this group, some accessions of P. trimera were nested in the paraphylic sub-groups because they did not share an immediate common ancestor.
The pattern of the phylogenetic tree constructed from the concatenated sequences was similar to that of ITS sequences (Fig. 5d). The tree included one monophyletic group with only L. scandens and one paraphyletic group with the accessions of P. trimera nested within P. confertifolia, A. buxifolia and S. monophylla.
Genetic distance analysis
The overall genetic distances for ITS, matK, rbcL and concatenated sequences were 0.11 ± 0.01, 0.29 ± 0.02, rbcL 0.48 ± 0.05 and 0.05 ± 0.0, respectively (Table 2). An overlap between the maximum intraspecific distances and the minimum interspecific distances were observed in the cases of ITS, rbcL and concatenated sequences (Table 2, Fig. 6a,c,d). In case of matK, a clear barcode gap was found between the maximum intraspecific distance (0.0028) and the minimum interspecific distance (0.0056). The histogram and ranked pairwise (K2P) distances demonstrated a significant difference in the cases of matK and rbcL (Fig. 6b,c).
Source: Ecology - nature.com
