Range-wide differential adaptation and genomic offset in critically endangered Asian rosewoods.

In the billion-dollar global illegal wildlife trade, rosewoods have been the world's most trafficked wild product since 2005. Dalbergia cochinchinensis and Dalbergia oliveri are the most sought-after rosewoods in the Greater Mekong Subregion. They are exposed to significant genetic risks and the lack of knowledge on their adaptability limits the effectiveness of conservation efforts. Here, we present genome assemblies and range-wide genomic scans of adaptive variation, together with predictions of genomic offset to climate change. Adaptive genomic variation was differentially associated with temperature and precipitation-related variables between the species, although their natural ranges overlap. The findings are consistent with differences in pioneering ability and in drought tolerance. We predict their genomic offsets will increase over time and with increasing carbon emission pathway but at a faster pace in D. cochinchinensis than in D. oliveri. These results and the distinct gene-environment association in the eastern coastal edge of Vietnam suggest species-specific conservation actions: germplasm representation across the range in D. cochinchinensis and focused on hotspots of genomic offset in D. oliveri. We translated our genomic models into a seed source matching application, seedeR, to rapidly inform restoration efforts. Our ecological genomic research uncovering contrasting selection forces acting in sympatric rosewoods is of relevance to conserving tropical trees globally and combating risks from climate change.

Exploring island syndromes: Variable matrix permeability in Phalaenopsis pulcherrima (Orchidaceae), a specialist lithophyte of tropical Asian inselbergs.

Introduction: Plants confined to island-like habitats are hypothesised to possess a suite of functional traits that promote on-spot persistence and recruitment, but this may come at the cost of broad-based colonising potential. Ecological functions that define this island syndrome are expected to generate a characteristic genetic signature. Here we examine genetic structuring in the orchid Phalaenopsis pulcherrima, a specialist lithophyte of tropical Asian inselbergs, both at the scale of individual outcrops and across much of its range in Indochina and on Hainan Island, to infer patterns of gene flow in the context of an exploration of island syndrome traits. Methods: We sampled 323 individuals occurring in 20 populations on 15 widely scattered inselbergs, and quantified genetic diversity, isolation-by-distance and genetic structuring using 14 microsatellite markers. To incorporate a temporal dimension, we inferred historical demography and estimated direction of gene flow using Bayesian approaches. Results: We uncovered high genotypic diversity, high heterozygosity and low rates of inbreeding, as well as strong evidence for the occurrence of two genetic clusters, one comprising the populations of Hainan Island and the other those of mainland Indochina. Connectivity was greater within, rather than between the two clusters, with the former unequivocally supported as ancestral. Discussion: Despite a strong capacity for on-spot persistence conferred by clonality, incomplete self-sterility and an ability to utilize multiple magnet species for pollination, our data reveal that P. pulcherrima also possesses traits that promote landscape-scale gene flow, including deceptive pollination and wind-borne seed dispersal, generating an ecological profile that neither fully conforms to, nor fully contradicts, a putative island syndrome. A terrestrial matrix is shown to be significantly more permeable than open water, with the direction of historic gene flow indicating that island populations can serve as refugia for postglacial colonisation of continental landmasses by effective dispersers.

A new species and two new records of Goniothalamus (Annonaceae) from Lao PDR.

Goniothalamus saccopetaloides Y.H. Tan & Bin Yang, a new species is described and illustrated from Laos. This species shows morphological similarities to G. yunnanensis W.T. Wang, but it differs from the latter by having almost fleshy, involute and saccate outer petals, subglobose monocarps, and single seeded monocarps. Goniothalamus cheliensis, and G. calvicarpus are new records for the Flora of Lao PDR. A key to Goniothalamus species indigenous to Laos is provided here.

An updated checklist of Begonia (Begoniaceae) in Laos, with two new species and five new records.

Two new species of Begonia L. (Begoniaceae), B. laotica (sect. Parvibegonia) and B. hypoleuca (sect. Reichenheimia), from north Laos are described and illustrated. Begonia augustinei, B. dryadis, B. lancangensis, B. sizemoreae and B. sillentensis subsp. mengyangensis were newly recorded taxa in Laos. Furthermore, an updated checklist of Begonia of Laos is also compiled.

Hmong herbal medicine and herbalists in Lao PDR: pharmacopeia and knowledge transmission.

BACKGROUND: In Lao PDR, the Hmong ethnic group has extensive knowledge about the use of medicinal plants. However, despite the importance of the Hmong pharmacopeia as a primary health care resource, no study has been undertaken to thoroughly document medicinal plant knowledge and its transmission. Objectives of this study are (i) to describe and characterize Hmong pharmacopeia, and (ii) to understand how medicinal plant knowledge is transmitted and spread among Hmong in Lao PDR, in order to assess whether this knowledge base is under threat. METHODS: In order to describe Hmong pharmacopeia, a total of 14 interlocutors were interviewed in three provinces (Bokeo, Xieng Khouang, and Vientiane), using "walk in the wood" methodology. To gain insight about knowledge transmission, semi-structured interviews were conducted with 28 people. Twenty of them were herbalists. Data analysis was performed using univariate analysis for the description of the pharmacopeia. Medicinal plant knowledge consistency was assessed through use and plant name overlapping. Answers to the semi-structured interview on knowledge transmission were analyzed qualitatively. RESULTS: Three hundred thirty-three different medicinal species were collected. The majority of uses attributed to plants were gastrointestinal conditions (22% of total use reports), gynecological conditions and sexually transmitted disease (12%), skin affections (8%), kidney and bladder problems (5%), physical traumas (5%), and aphrodisiac (or male tonics; 5%). Use convergences are more marked in the gynecological sphere, but there is a strong heterogeneity in practices and knowledge. Medicinal plant knowledge transmission is oral, gained from direct experience since childhood, matrilineal, and kept strictly within the family lineage. Apparent limited consensus on uses might stem from the method of knowledge transmission and to the economic value given to medicinal plants. DISCUSSION: Use pattern of species from the Hmong pharmacopeia does not appear to be strikingly different from the national Lao pharmacopeia. Differences may lie in the methods and reasons for knowledge transmission. It can be proposed that the economic value given to plants helps in keeping the knowledge alive, and encourages its transmission. CONCLUSION: Hmong traditional medicine is constantly evolving in a dynamic process and aims to respond to health problems faced by the local population. Herbalists appear as health fully fledged actors and should be recognized and valued as such.

Population genetic structure of the endemic rosewoods Dalbergia cochinchinensis and D. oliveri at a regional scale reflects the Indochinese landscape and life-history traits.

Indochina is a biodiversity hot spot and harbors a high number of endemic species, most of which are poorly studied. This study explores the genetic structure and reproductive system of the threatened endemic timber species Dalbergia cochinchinensis and Dalbergia oliveri using microsatellite data from populations across Indochina and relates it to landscape characteristics and life-history traits. We found that the major water bodies in the region, Mekong and Tonle Sap, represented barriers to gene flow and that higher levels of genetic diversity were found in populations in the center of the distribution area, particularly in Cambodia. We suggest that this pattern is ancient, reflecting the demographic history of the species and possible location of refugia during earlier time periods with limited forest cover, which was supported by signs of old genetic bottlenecks. The D. oliveri populations had generally high levels of genetic diversity (mean He = 0.73), but also strong genetic differentiation among populations (global GST = 0.13), while D. cochinchinensis had a moderate level of genetic diversity (mean He = 0.55), and an even stronger level of differentiation (global GST = 0.25). These differences in genetic structure can be accounted for by a higher level of gene flow in D. oliveri due to a higher dispersal capacity, but also by the broader distribution area for D. oliveri, and the pioneer characteristics of D. cochinchinensis. This study represents the first detailed analysis of landscape genetics for tree species in Indochina, and the found patterns might be common for other species with similar ecology.

New finding of an anti-TB compound in the genus Marsypopetalum (Annonaceae) from a traditional herbal remedy of Laos.

ETHNOPHARMACOLOGICAL RELEVANCE: There is widespread use of traditional herbal remedies in the Lao PDR (Laos). It is common practice to treat many diseases with local plants. This research project documented and analysed some of these traditional remedies used to treat symptoms of tuberculosis (TB). MATERIALS AND METHODS: This research was executed by interviewing healers about plants used traditionally to treat the symptoms of TB. Samples of some of the plants were collected, and extracts of 77 species were submitted to various in vitro assays in order to determine the amount of growth inhibition of virulent Mycobacterium tuberculosis H37Rv (Mtb), as opposed to other microbes and mammalian Vero cells. RESULTS: Interviews took place with 58 contemporary healers in 5 different provinces about plants currently used, giving a list of 341 plants. Bioassay-guided fractionation was performed on Marsypopetalum modestum (Pierre) B. Xue and R.M.K. Saunders (Annonaceae), leading to the isolation of dipyrithione, an anti-mycobacterial compound isolated for the first time from the genus Marsypopetalum through this research. CONCLUSIONS: This research has helped to increase awareness of Laos' rich diversity of medicinal plants and will hopefully provide incentive to preserve the undeveloped forested areas that remain, which still hold a wealth of medical information for future discoveries.

Study of antimalarial activity of chemical constituents from Diospyros quaesita.

Bioassay-directed fractionation led to the isolation of seven compounds from a sample of the dried leaves, twigs, and branches of Diospyros quaesita Thw. (Ebenaceae). One of the isolates, betulinic acid 3-caffeate (1), showed in vitro antimalarial activity against Plasmodium falciparum clones D(6) (chloroquine-sensitive) and W(2) (chloroquine-resistant) with IC(50) values of 1.40 and 0.98 microM, respectively. Evaluation of compound 1 in the human oral epidermoid (KB) cancer cell line revealed cytotoxicity at ED(50) of 4.0 microM. In an attempt to reduce the cytotoxicity of 1, the acetylated derivative 1a and betulinic acid (1b) were prepared. Of the seven isolates, diospyrosin (2) was determined to be a new neolignan. In addition to 1, other known compounds isolated in this study were pinoresinol, lariciresinol, N-benzoyl-L-phenylalaninol, scopoletin, and poriferast-5-en-3beta,7alpha-diol. The structure of 2 was elucidated based on spectroscopic data analysis including 1D- and 2D-NMR, and HR-ESI-MS.

A first new antimalarial pregnane glycoside from Gongronema napalense.

As a part of the UIC-based ICBG project in Laos, plants were collected based on ethnomedical interviews and evaluated for antimalarial activity. A CHCl3 extract from the vine of Gongronema napalense (Wall.) Decne. (Asclepiadaceae) showed promising anti-malarial activity while exhibiting low levels of cytotoxicity and was thus followed up with further fractionation and biological evaluation. Bioassay-guided fractionation led to the isolation of a new steroidal glycoside, gongroneside A, which showed antimalarial activity in vitro with an IC50 value of 1.60 and 1.39 µM against the Plasmodium falciparum D6 and W2 clones, respectively.

Rourinoside and rouremin, antimalarial constituents from Rourea minor.

Bioassay-directed fractionation of the antimalarial active CHCl(3) extract of the dried stems of Rourea minor (Gaertn.) Aubl. (Connaraceae) liana led to isolation of two glycosides, rourinoside (1) and rouremin (2), as well as five known compounds, 1-(26-hydroxyhexacosanoyl)-glycerol (3), 1-O-beta-D-glucopyranosyl-(2S,3R,4E-8Z)-2-N-(2'-hydroxypalmitoyl)-octadecasphinga-4,8-dienine, 9S,12S,13S-trihydroxy-10E-octadecenoic acid, dihydrovomifoliol-9-beta-D-glucopyranoside, and beta-sitosterol glucoside. Compounds 1-3 showed weak in vitro activities against Plasmodium falciparum. Their structures and stereochemistry were elucidated by spectroscopic methods and selected enzyme hydrolysis.