Variations and driving factors of leaf functional traits in the dominant desert plant species along an environmental gradient in the drylands of China.

Leaf functional traits (LFTs) of desert plants are responsive, adaptable and highly plastic to their environment. However, the macroscale variation in LFTs and driving factors underlying this variation remain unclear, especially for desert plants. Here, we measured eight LFTs, including leaf carbon concentration (LCC), leaf nitrogen concentration (LNC), leaf phosphorus concentration (LPC), specific leaf area (SLA), leaf dry matter content (LDMC), leaf mass per area (LMA), leaf thickness (LTH) and leaf tissue density (LTD) across 114 sites along environmental gradient in the drylands of China and in Guazhou Common Garden and evaluated the effect of environment and phylogeny on the LFTs. We noted that for all species, the mean values of LCC, LNC, LPC, SLA, LDMC, LMA, LTH and LTD were 384.62 mg g-1, 19.91 mg g-1, 1.12 mg g-1, 79.62 cm2 g-1, 0.74 g g-1, 237.39 g m-2, 0.38 mm and 0.91 g cm-3, respectively. LFTs exhibited significant geographical variations and the LNC, LMA and LTH in the plants of Guazhou Common Garden were significantly higher than the field sites in the drylands of China. LDMC and LTD of plants in Guazhou Common Garden were, however, considerably lower than those in the drylands of China. LCC, LPC, LTH and LTD differed significantly among different plant lifeforms, while LNC, SLA, LDMC and LMA didn't show significant variations. We found that the environmental variables explained higher spatial variations (3.6-66.3 %) in LFTs than the phylogeny (1.8-54.2 %). The LCC significantly increased, while LDMC and LTD decreased with increased temperature and reduced precipitation. LPC, LDMC, LMA, and LTD significantly increased, while SLA and LTH decreased with increased aridity. However, leaf elements were not significantly correlated with soil nutrients. The mean annual precipitation was a key factor controlling variations in LFTs at the macroscale in the drylands of China. These findings will provide new insights to better understand the response of LFTs and plants adaptation along environmental gradient in drylands, and will serve as a reference for studying biogeographic patterns of leaf traits.

A chromosome-scale genome assembly of a diploid alfalfa, the progenitor of autotetraploid alfalfa.

Alfalfa (Medicago sativa L.) is one of the most important and widely cultivated forage crops. It is commonly used as a vegetable and medicinal herb because of its excellent nutritional quality and significant economic value. Based on Illumina, Nanopore and Hi-C data, we assembled a chromosome-scale assembly of Medicago sativa spp. caerulea (voucher PI464715), the direct diploid progenitor of autotetraploid alfalfa. The assembled genome comprises 793.2 Mb of genomic sequence and 47,202 annotated protein-coding genes. The contig N50 length is 3.86 Mb. This genome is almost twofold larger and contains more annotated protein-coding genes than that of its close relative, Medicago truncatula (420 Mb and 44,623 genes). The more expanded gene families compared with those in M. truncatula and the expansion of repetitive elements rather than whole-genome duplication (i.e., the two species share the ancestral Papilionoideae whole-genome duplication event) may have contributed to the large genome size of M. sativa spp. caerulea. Comparative and evolutionary analyses revealed that M. sativa spp. caerulea diverged from M. truncatula ~5.2 million years ago, and the chromosomal fissions and fusions detected between the two genomes occurred during the divergence of the two species. In addition, we identified 489 resistance (R) genes and 82 and 85 candidate genes involved in the lignin and cellulose biosynthesis pathways, respectively. The near-complete and accurate diploid alfalfa reference genome obtained herein serves as an important complement to the recently assembled autotetraploid alfalfa genome and will provide valuable genomic resources for investigating the genomic architecture of autotetraploid alfalfa as well as for improving breeding strategies in alfalfa.

Complete chloroplast genome of a valuable medicinal plant, Huperzia serrata (Lycopodiaceae), and comparison with its congener.

PREMISE OF THE STUDY: Here we report the complete chloroplast genome of the important medicinal species Huperzia serrata (Lycopodiaceae) and compare it to the chloroplast genome of the congeneric species H. lucidula. METHODS AND RESULTS: The whole chloroplast genome of H. serrata was sequenced using an Illumina platform and assembled with Geneious version R9.0.5. The genome size of H. serrata was 154,176 bp, with 36.3% GC content. The complete chloroplast genome contained 120 unique genes, including 86 coding genes, four rRNA genes, and 30 tRNA genes. Comparison with the chloroplast genome of H. lucidula revealed three highly variable regions (rps16-chlB, ycf12-trnR, and ycf1) between these two species and 252 mutation events including 27 insertion/deletion polymorphisms and 225 single-nucleotide polymorphisms (SNPs). Ninety-two SNPs were identified in the gene-coding regions. In addition, 18 microsatellite sites were found, which can potentially be used in phylogeographic studies. CONCLUSIONS: The complete chloroplast genome of H. serrata is reported here, and will be a valuable genome resource for further phylogenetic, evolutionary, and medical studies of medicinal plants in the genus Huperzia.

Medicinal plant diversity and traditional healing practices in eastern Nepal.

ETHNOPHARMACOLOGICAL RELEVANCE: The rich floral and ethnic composition of eastern Nepal and the widespread utilization of locally available medicinal plants offer remarkable opportunity for ethnomedicinal research. The present paper aims to explore medicinal plant diversity and use in the remote villages of eastern Nepal. It also aims to evaluate ethnopharmacological significance of the documented use reports and identify species of high indigenous priority. MATERIALS AND METHODS: The study was undertaken in four villages located in the Sankhuwasabha district in eastern Nepal. Ethnomedicinal information was collected through structured interviews. The homogeneity of informant's knowledge and the relative importance of documented medicinal plants were validated by informant consensus factor and use value, respectively. Species preference for treatment of particular diseases was evaluated through fidelity level. RESULTS: We reported medicinal properties of 48 species belonging to 33 families and 40 genera, for the treatment of 37 human ailments. The uses of 10 medicinal plants were previously undocumented. The informant consensus factor (FIC) ranged between 0.38 and 1 with about 50% of values greater than 0.80 and over 75% of values greater than 0.70, indicating moderate to high consensus among the informants on the use of medicinal plants in the region. Swertia chirayita was the most preferred species with significantly high use values, followed by Paris polyphylla and Neopicrorhiza scrophulariiflora. CONCLUSIONS: The remote villages in eastern Nepal possess rich floral and cultural diversity with strong consensus among informants on utilization of plants for local healthcare. The direct pharmacological evidence for medicinal properties of most species indicates high reliability of documented information. Careful and systematic screening of compounds isolated from these plants could possibly provide good opportunity for the discovery of novel medicines to treat life-threatening human diseases. We recommend prioritization of medicinal plants and reinforcement of existing cultivation practices for sustainable management of high-priority species.

Ethnomedicinal practices in the highlands of central Nepal: a case study of Syaphru and Langtang village in Rasuwa district.

ETHNOPHARMACOLOGICAL RELEVANCE: The present paper documents the utilization of medicinal plants for the treatment of various human ailments in two village development committees in the Rasuwa district of central Nepal. It also evaluates the ethnopharmacological significance of the documented reports and identifies species of high indigenous priority in local therapeutics. MATERIALS AND METHODS: The ethnobotanical information was collected by interviews and group discussions using standard ethnobotanical procedures. The homogeneity of informant׳s knowledge was validated by Informant consensus factor (F(IC)) and the relative importance of a plant species used as medicine in the study area was calculated with the help of use value (UV). RESULTS: The present study identified a total of 46 medicinal plants belonging to 26 families used for the treatment of 38 human ailments. Besides medicinal uses, the study has also documented the culinary and cultural use of 13 species of medicinal plants. The most commonly used part was root constituting about 42% of the total utilized plants. The most commonly used form of preparation was paste (31.91%). We found new usage reports for 9 medicinal plants. The F(IC) value in the present study ranged from 0.66 to 1 with 84.6% values greater than 0.8 indicating high consensus among the informants. The most preferred species was Neopicrorhiza scrophulariflora (UV=0.96) and the lowest used value was found for Lyonia ovalifolia (UV=0.32). CONCLUSIONS: People of Rasuwa possess rich traditional knowledge in medicinal plants utilization with strong consensus among local people on the utilization of species evident by higher F(IC) values in different ailment categories. Strong pharmacological evidence for a majority of species being currently used as medicines shows that the plants used in local therapeutics are likely to be more effective in treating different medical ailments. The bioactive compounds extracted from these medicinal plants could subsequently be used in the creation of novel drugs to treat life threatening human diseases. The species with high use values are the ones likely to be more vulnerable because of high demand and high collection pressure. Therefore, it is imperative to prioritize such species for cultivation and sustainable management in order to ensure their long term availability.