Search

Cymbidium (Orchidaceae: Epidendroideae), with around 60 species, is widely-distributed across Southeast Asia, providing a nice system for studying the processes that underlie patterns of biodiversity in the region. However, phylogenetic relationships of Cymbidium have not been well resolved, hampering investigations of species diversification and the biogeographical history of this genus. In this study, we construct a plastome phylogeny of 56 Cymbidium species, with four well-resolved major clades, which provides a framework for biogeographical and diversification rate analyses. Molecular dating and biogeographical analyses show that Cymbidium likely originated in the region spanning northern Indo-Burma to the eastern Himalayas during the early Miocene (∼21.10 Ma). It then rapidly diversified into four major clades in East Asia within approximately a million years during the middle Miocene. Cymbidium spp. migration to the adjacent regions (Borneo, Philippines, and Sulawesi) primarily occurred during the Pliocene-Pleistocene period. Our analyses indicate that the net diversification rate of Cymbidium has decreased since its origin, and is positively associated with changes in temperature and monsoon intensity. Favorable hydrothermal conditions brought by monsoon intensification in the early Miocene possibly contributed to the initial rapid diversification, after which the net diversification rate was reduced with the cooling climate after the middle Miocene. The transition from epiphytic to terrestrial habits may have enabled adaptation to cooler environments and colonization of northern niches, yet without a significant effect on diversification rates. This study provides new insights into how monsoon activity and temperature changes affected the diversification dynamics of plants in Southeast Asia.

Abstract Inflammatory bowel disease (IBD) is a significant global health concern. The gut microbiota plays an essential role in the onset and development of IBD. Sanghuangporus (SH), a traditional Chinese medicinal mushroom, has excellent anti‐inflammatory effects and is effective at modulating the gut microbiota. Despite these attributes, the specific anticolitic effects of SH and the mechanisms through which the gut microbiota mediates its benefits remain unclear. Herein, we demonstrated that polyphenol‐rich extract from SH effectively alleviated the pathological symptoms of dextran sodium sulfate (DSS)‐induced colitis in mice by modulating the gut microbiota. Treatment with SH distinctly enriched Alistipes, especially Alistipes onderdonkii, and its metabolite 5‐hydroxyindole‐3‐acetic acid (5HIAA). Oral gavage of live A. onderdonkii or 5HIAA potently mitigated DSS‐induced colitis in mice. Moreover, both 5HIAA and SH significantly activated the aromatic hydrocarbon receptor (AhR), and the administration of an AhR antagonist abrogated their protective effects against colitis. These results underscore the potent efficacy of SH in diminishing DSS‐induced colitis through the promotion of A. onderdonkii and 5HIAA, ultimately activating AhR signaling. This study unveils potential avenues for developing therapeutic strategies for colitis based on the interplay between SH and the gut microbiota.

Abstract Background Flowering plants (angiosperms) are dominant components of global terrestrial ecosystems, but phylogenetic relationships at the familial level and above remain only partially resolved, greatly impeding our full understanding of their evolution and early diversification. The plastome, typically mapped as a circular genome, has been the most important molecular data source for plant phylogeny reconstruction for decades. Results Here, we assembled by far the largest plastid dataset of angiosperms, composed of 80 genes from 4792 plastomes of 4660 species in 2024 genera representing all currently recognized families. Our phylogenetic tree (PPA II) is essentially congruent with those of previous plastid phylogenomic analyses but generally provides greater clade support. In the PPA II tree, 75% of nodes at or above the ordinal level and 78% at or above the familial level were resolved with high bootstrap support (BP ≥ 90). We obtained strong support for many interordinal and interfamilial relationships that were poorly resolved previously within the core eudicots, such as Dilleniales, Saxifragales, and Vitales being resolved as successive sisters to the remaining rosids, and Santalales, Berberidopsidales, and Caryophyllales as successive sisters to the asterids. However, the placement of magnoliids, although resolved as sister to all other Mesangiospermae, is not well supported and disagrees with topologies inferred from nuclear data. Relationships among the five major clades of Mesangiospermae remain intractable despite increased sampling, probably due to an ancient rapid radiation. Conclusions We provide the most comprehensive dataset of plastomes to date and a well-resolved phylogenetic tree, which together provide a strong foundation for future evolutionary studies of flowering plants.

BackgroundWhile the relationship between blood pressure and blood lead has been studied more extensively, the effect of high-density lipoprotein (HDL) concentration on this relationship remains uncertain. Therefore, this study aimed to determine the effect of HDL concentration on the relationship between blood lead and blood pressure.MethodsThe research used cross-sectional data from the 2005 to 2014 National Health and Nutrition Examination Survey (NHANES), which included 16,451 participants aged 20–60 years. Multivariable linear regression was used to evaluate the correlation among blood lead, systolic blood pressure (SBP), and diastolic blood pressure (DBP). HDL concentration was determined by low HDL concentration (≤ 49 mg/dl) and high HDL concentration (>49 mg/dl) stratified. The effect of HDL concentration was assessed by an interaction test between blood lead and SBP in multivariable linear regression.ResultsIn this cross-sectional research, we identified a positive correlation between blood lead and SBP, but not DBP. The relationship between blood lead and SBP was different in the group with low and high HDL concentrations (β: 0.21 95% Cl:−0.05-0.46 vs. β:0.47 95% Cl: 0.15-0.79). In addition, high HDL significantly altered the positive correlation between blood lead and SBP (P-value of interaction < 0.001).ConclusionThe study suggests an interaction between HDL and blood lead in elevating SBP, which may have important clinical implications.

Species of Cephalotaxus have great economic and ecological values. However, the taxonomy and interspecific phylogenetic relationships within the genus have been controversial and remained not fully resolved until now. To date, no study examined the efficiency of the complete plastome as super-barcode across Cephalotaxus species with multiple samples per taxon. In this study, we have evaluated the complete plastome in species discrimination and phylogenetic resolution in Cephalotaxus by including 32 individuals of all eight recognized species and five varieties following Farjon’s classification (2010) with multiple samples per taxon. Our results indicated that not all species recognized in recent taxonomic revisions of Cephalotaxus could be distinguished and not all were monophyletic. Based on the plastome phylogeny, a new taxonomic classification for the genus comprising nine species and two varieties, including a cryptic species, was proposed. The phylogeny also resolved all interspecific relationships. Compared to the plastome based classification, standard DNA barcodes, alone or in combination, only recognized a maximum of seven out of the nine species. Moreover, two highly variable single loci, ycf1 and rps16, each alone achieved full species discrimination. With the moderate length of 1079 bp, rps16 is proposed as a specific barcode to discriminate Cephalotaxus species. The super-barcodes and specific barcode candidates will aid in the identification of endangered Cephalotaxus species, and to help focus conservation measures.

Abstract GetOrganelle is a state-of-the-art toolkit to accurately assemble organelle genomes from whole genome sequencing data. It recruits organelle-associated reads using a modified “baiting and iterative mapping” approach, conducts de novo assembly, filters and disentangles the assembly graph, and produces all possible configurations of circular organelle genomes. For 50 published plant datasets, we are able to reassemble the circular plastomes from 47 datasets using GetOrganelle. GetOrganelle assemblies are more accurate than published and/or NOVOPlasty-reassembled plastomes as assessed by mapping. We also assemble complete mitochondrial genomes using GetOrganelle. GetOrganelle is freely released under a GPL-3 license ( https://github.com/Kinggerm/GetOrganelle ).

Paris L. section Axiparis H. Li (Melanthiaceae) is a taxonomically perplexing taxon with considerable confusion regarding species delimitation. Based on the analyses of morphology and geographic distribution of each species currently recognized in the taxon, we propose a revision scheme that reduces the number of species in P. sect. Axiparis from nine to two. To verify this taxonomic proposal, we employed a genome skimming approach to recover the plastid genomes (plastomes) and nuclear ribosomal DNA (nrDNA) regions of 51 individual plants across the nine described species of P. sect. Axiparis by sampling multiple accessions per species. The species boundaries within P. sect. Axiparis were explored using phylogenetic inference and three different sequence-based species delimitation methods (ABGD, mPTP, and SDP). The mutually reinforcing results indicate that there are two species-level taxonomic units in P. sect. Axiparis (Paris forrestii s.l. and P. vaniotii s.l.) that exhibit morphological uniqueness, non-overlapping distribution, genetic distinctiveness, and potential reproductive isolation, providing strong support to the proposed species delimitation scheme. This study confirms that previous morphology-based taxonomy overemphasized intraspecific and minor morphological differences to delineate species boundaries, therefore resulting in an overestimation of the true species diversity of P. sect. Axiparis. The findings clarify species limits and will facilitate robust taxonomic revision in P. sect. Axiparis.

Morphological approaches often fail to delimit species in recently derived species complexes. This can be exacerbated in historical collections which may have lost key features in specimen preparation and preservation. Here, we examine the Pedicularis siphonantha complex, endemic to the Mountains of Southwest China. This complex is characterized by its red/purple/pink and long-tubular corolla, and twisted, beaked galea. However, herbarium specimens are often difficult to identify to species. Molecular approaches using nrITS or nuclear ribosomal internal transcribed spacer (nrITS) + plastid DNA (ptDNA) have been successfully used for species identification in Pedicularis. To resolve taxonomic confusion in the Pedicularis siphonantha complex, we reconstructed phylogenies of the complex using nrITS and four plastid DNA loci (matK, rbcL, trnH-psbA, and trnL-F). To recover as much of the phylogenetic history as possible, we sampled individuals at the population level. Topological incongruence between the nrITS and ptDNA datasets was recovered in clades including two widely distributed species, Pedicularis milliana and Pedicularis tenuituba. Based on morphological, geographical, and genetic evidence, we suggest that hybridization/introgression has occurred between P. milliana and Pedicularis sigmoidea/Pedicularis sp. 1 in the Yulong Snow Mountain of Lijiang, northwest Yunnan, and between P. tenuituba and Pedicularis leptosiphon in Ninglang, northwest Yunnan. After removing conflicting DNA regions in Pedicularis dolichosiphon (nrITS) and P. milliana (ptDNA), the concatenated nrITS and ptDNA phylogenies distinguish 11 species in the P. siphonantha complex, including two undescribed species, from the Jiaozi and Yulong Snow Mountains, respectively. Phylogeographical analyses indicate that the P. siponantha complex originated from south of the Hengduan Mountains, expanding north to the Himalayas and the Yunnan-Guizhou Plateau. Moreover, the uplift of the Qinghai-Tibet Plateau and climate oscillations may have driven further diversification in the complex.

The Poales is one of the largest orders of flowering plants with significant economic and ecological values. Reconstructing the phylogeny of the Poales is important for understanding its evolutionary history that forms the basis for biological studies. However, due to sparse taxon sampling and limited molecular data, previous studies have resulted in a variety of contradictory topologies. In particular, there are three nodes surrounded by incongruence: the phylogenetic ambiguity near the root of the Poales tree, the sister family of Poaceae, and the delimitation of the xyrid clade. We conducted a comprehensive sampling and reconstructed the phylogenetic tree using plastid and mitochondrial genomic data from 91 to 66 taxa, respectively, representing all the 16 families of Poales. Our analyses support the finding of Bromeliaceae and Typhaceae as the earliest diverging groups within the Poales while having phylogenetic relationships with the polytomy. The clade of Ecdeiocoleaceae and Joinvilleaceae is recovered as the sister group of Poaceae. The three families, Mayacaceae, Eriocaulaceae, and Xyridaceae, of the xyrid assembly diverged successively along the backbone of the Poales phylogeny, and thus this assembly is paraphyletic. Surprisingly, we find substantial phylogenetic conflicts within the plastid genomes of the Poales, as well as among the plastid, mitochondrial, and nuclear data. These conflicts suggest that the Poales could have a complicated evolutionary history, such as rapid radiation and polyploidy, particularly allopolyploidy through hybridization. In sum, our study presents a new perspicacity into the complex phylogenetic relationships and the underlying phylogenetic conflicts within the Poales.

With c. 2,000 species, Euphorbia is one of the largest angiosperm genera, yet a lack of chloroplast genome (plastome) resources impedes a better understanding of its evolution. In this study, we assembled and annotated 28 plastomes from Euphorbiaceae, of which 15 were newly sequenced. Phylogenomic and comparative analyses of 22 plastome sequences from all four recognized subgenera within Euphorbia revealed that plastome length in Euphorbia is labile, presenting a range of variation c. 42 kb. Large-scale expansions of the inverted repeat (IR) region were identified, and at the extreme opposite, the near-complete loss of the IR region (with only 355 bp left) was detected for the first time in Euphorbiaceae. Other structural variations, including gene inversion and duplication, and gene loss/pseudogenization, were also observed. We screened the most promising molecular markers from both intergenic and coding regions for phylogeny-based utilities, and estimated maximum likelihood and Bayesian phylogenies from four datasets including whole plastome sequences. The monophyly of Euphorbia is supported, and its four subgenera are recovered in a successive sister relationship. Our study constitutes the first comprehensive investigation on the plastome structural variation in Euphorbia and it provides resources for phylogenetic research in the genus, facilitating further studies on its taxonomy, evolution, and conservation.

Abstract Background Paris (Melanthiaceae) is an economically important but taxonomically difficult genus, which is unique in angiosperms because some species have extremely large nuclear genomes. Phylogenetic relationships within Paris have long been controversial. Based on complete plastomes and nuclear ribosomal DNA (nrDNA) sequences, this study aims to reconstruct a robust phylogenetic tree and explore historical biogeography and clade diversification in the genus. Results All 29 species currently recognized in Paris were sampled. Whole plastomes and nrDNA sequences were generated by the genome skimming approach. Phylogenetic relationships were reconstructed using the maximum likelihood and Bayesian inference methods. Based on the phylogenetic framework and molecular dating, biogeographic scenarios and historical diversification of Paris were explored. Significant conflicts between plastid and nuclear datasets were identified, and the plastome tree is highly congruent with past interpretations of the morphology. Ancestral area reconstruction indicated that Paris may have originated in northeastern Asia and northern China, and has experienced multiple dispersal and vicariance events during its diversification. The rate of clade diversification has sharply accelerated since the Miocene/Pliocene boundary. Conclusions Our results provide important insights for clarifying some of the long-standing taxonomic debates in Paris. Cytonuclear discordance may have been caused by ancient and recent hybridizations in the genus. The climatic and geological changes since the late Miocene, such as the intensification of Asian monsoon and the rapid uplift of Qinghai-Tibet Plateau, as well as the climatic fluctuations during the Pleistocene, played essential roles in driving range expansion and radiative diversification in Paris. Our findings challenge the theoretical prediction that large genome sizes may limit speciation.

Abstract Background The genus Ilex (Aquifoliaceae) has a near-cosmopolitan distribution in mesic habitats from tropical to temperate lowlands and in alpine forests. It has a high rate of hybridization and plastid capture, and comprises four geographically structured plastid groups. A previous study showed that the plastid rbcL gene, coding for the large subunit of Rubisco, has a particularly high rate of non-synonymous substitutions in Ilex, when compared with other plant lineages. This suggests a strong positive selection on rbcL, involved in yet unknown adaptations. We therefore investigated positive selection on rbcL in 240 Ilex sequences from across the global range. Results The rbcL gene shows a much higher rate of positive selection in Ilex than in any other plant lineage studied so far (> 3000 species) by tests in both PAML and SLR. Most positively selected residues are on the surface of the folded large subunit, suggesting interaction with other subunits and associated chaperones, and coevolution between positively selected residues is prevalent, indicating compensatory mutations to recover molecular stability. Coevolution between positively selected sites to restore global stability is common. Conclusions This study has confirmed the predicted high incidence of positively selected residues in rbcL in Ilex, and shown that this is higher than in any other plant lineage studied so far. The causes and consequences of this high incidence are unclear, but it is probably associated with the similarly high incidence of hybridization and introgression in Ilex, even between distantly related lineages, resulting in large cytonuclear discordance in the phylogenies.

The typical plastid genome (plastome) of photosynthetic angiosperms comprises a pair of Inverted Repeat regions (IRs), which separate a Large Single Copy region (LSC) from a Small Single Copy region (SSC). The independent losses of IRs have been documented in only a few distinct plant lineages. The majority of these taxa show uncommonly high levels of plastome structural variations, while a few have otherwise conserved plastomes. For a better understanding of the function of IRs in stabilizing plastome structure, more taxa that have lost IRs need to be investigated. We analyzed the plastomes of eight species from two genera of the putranjivoid clade of Malpighiales using Illumina paired-end sequencing, the de novo assembly strategy GetOrganelle, as well as a combination of two annotation methods. We found that all eight plastomes of the putranjivoid clade have lost their IRB, representing the fifth case of IR loss within autotrophic angiosperms. Coinciding with the loss of the IR, plastomes of the putranjivoid clade have experienced significant structural variations including gene and intron losses, multiple large inversions, as well as the translocation and duplication of plastome segments. However, Balanopaceae, one of the close relatives of the putranjivoid clade, exhibit a relatively conserved plastome organization with canonical IRs. Our results corroborate earlier reports that the IR loss and additional structural reorganizations are closely linked, hinting at a shared mechanism that underpins structural disturbances.

Ultra-barcoding is a technique using whole plastomes and nuclear ribosomal DNA (nrDNA) sequences for plant species identification. Paris yunnanensis is a medicinal plant of great economic importance for the pharmaceutical industry. However, the alpha taxonomy of P. yunnanensis is still uncertain, hindering effective conservation and management of the germplasm. To resolve long-standing taxonomic disputes regarding this species, we newly generated the complete plastomes and nrDNA sequences from 22 P. yunnanensis accessions. Ultra-barcoding analyses suggest that P. yunnanensis as currently circumscribed is made up of two distinct genetic lineages, corresponding to the two phenotypes (“typical” and “high stem” form) identified early in our study. With distinct morphologies and distribution, the “high stem” form should be recognized as a previously unrecognized species; here it is described as a new species, P. liiana sp. nov. Moreover, the ultra-barcoding data do not support treatment of P. yunnanensis as a conspecific variety under Paris polyphylla. Our study represents a guiding practical application of ultra-barcoding for discovery of cryptic species in taxonomically challenging plant taxa. The findings highlight the great potential of ultra-barcoding as an effective tool for resolving perplexing problems in plant taxonomy.

Abstract Background The world’s herbaria contain millions of specimens, collected and named by thousands of researchers, over hundreds of years. However, this treasure has remained largely inaccessible to genetic studies, because of both generally limited success of DNA extraction and the challenges associated with PCR-amplifying highly degraded DNA. In today’s next-generation sequencing world, opportunities and prospects for historical DNA have changed dramatically, as most NGS methods are actually designed for taking short fragmented DNA molecules as templates. Results As a practical test of routine recovery of rDNA and plastid genome sequences from herbarium specimens, we sequenced 25 herbarium specimens up to 80 years old from 16 different Angiosperm families. Paired-end reads were generated, yielding successful plastid genome assemblies for 23 species and nuclear rDNAs for 24 species, respectively. These data showed that genome skimming can be used to generate genomic information from herbarium specimens as old as 80 years and using as little as 500 pg of degraded starting DNA. Conclusions The routine plastome sequencing from herbarium specimens is feasible and cost-effective (compare with Sanger sequencing or plastome-enrichment approaches), and can be performed with limited sample destruction.

The authors established the taxonomic status of endophytic fungi associated with leaves of Pandanaceae collected from southern Thailand. Morphotypes were initially identified based on their characteristics in culture and species level identification was done based on both morphological characteristics and phylogenetic analyses of DNA sequence data. Twenty-two isolates from healthy leaves were categorised into eight morphotypes. Appropriate universal primers were used to amplify specific gene regions and phylogenetic analyses were performed to identify these endophytes and established relationships with extant fungi. The authors identified both ascomycete and basidiomycete species, including one new genus, seven new species and nine known species. Morphological descriptions, colour plates and phylogenies are given for each taxon.

We reported the first mitogenome of Pedicularis from P. rex (Orobanchaceae), which is endemic to SW China. The complete mitochondrial genome (mitogenome or chondriome) was a single circular chromosome that was 219,859 bp in length. It contains 56 genes, including 34 protein-coding (cox2 and atp9 with two copies), 19 transfer RNA (tRNA), and three ribosomal RNA (rRNA) genes. Phylogenetic analysis showed that Pedicularis rex was closely related to Castilleja paramensis.

Phtheirospermum (Orobanchaceae), a hemiparasitic genus of Eastern Asia, is characterized by having long and viscous glandular hairs on stems and leaves. Despite this unifying character, previous phylogenetic analyses indicate that Phtheirospermum is polyphyletic, with Phtheirospermum japonicum allied with tribe Pedicularideae and members of the Ph. tenuisectum complex allied with members of tribe Rhinantheae. However, no analyses to date have included broad phylogenetic sampling necessary to test the monophyly of Phtheirospermum species, and to place these species into the existing subfamiliar taxonomic organization of Orobanchaceae. Two other genera of uncertain phylogenetic placement are Brandisia and Pterygiella, also both of Eastern Asia. In this study, broadly sampled phylogenetic analyses of nrITS and plastid DNA revealed hard incongruence between these datasets in the placement of Brandisia. However, both nrITS and the plastid datasets supported the placement of Ph. japonicum within tribe Pedicularideae, and a separate clade consisting of the Ph. tenuisectum complex and a monophyletic Pterygiella. Analyses were largely in agreement that Pterygiella, the Ptheirospermum complex, and Xizangia form a clade not nested within any of the monophyletic tribes of Orobanchaceae recognized to date. Ph. japonicum, a model species for parasitic plant research, is widely distributed in Eastern Asia. Despite this broad distribution, both nrITS and plastid DNA regions from a wide sampling of this species showed high genetic identity, suggesting that the wide species range is likely due to a recent population expansion. The Ph. tenuisectum complex is mainly distributed in the Hengduan Mountains region. Two cryptic species were identified by both phylogenetic analyses and morphological characters. Relationships among species of the Ph. tenuisectum complex and Pterygiella remain uncertain. Estimated divergence ages of the Ph. tenuisectum complex corresponding to the last two uplifts of the Qinghai–Tibet Plateau at around 8.0–7.0 Mya and 3.6–1.5 Mya indicated that the development of a hot-dry valley climate during these uplifts may have driven species diversification in the Ph. tenuisectum complex.

Although China and India are the two largest tea-producing countries, the domestication origin and breeding history of the tea plant in these two countries remain unclear. Our previous study suggested that the tea plant includes three distinct lineages (China type tea, Chinese Assam type tea and Indian Assam type tea), which were independently domesticated in China and India, respectively. To determine the origin and historical timeline of tea domestication in these two countries we used a combination of 23 nSSRs (402 samples) and three cpDNA regions (101 samples) to genotype domesticated tea plants and its wild relative. Based on a combination of demographic modeling, NewHybrids and Neighbour joining tree analyses, three independent domestication centers were found. In addition, two origins of Chinese Assam type tea were detected: Southern and Western Yunnan of China. Results from demographic modeling suggested that China type tea and Assam type tea first diverged 22,000 year ago during the last glacial maximum and subsequently split into the Chinese Assam type tea and Indian Assam type tea lineages 2770 year ago, corresponding well with the early record of tea usage in Yunnan, China. Furthermore, we found that the three tea types underwent different breeding histories where hybridization appears to have been the most important approach for tea cultivar breeding and improvements: a high proportion of the hybrid lineages were found to be F2 and BCs. Collectively, our results underscore the necessity for the conservation of Chinese Assam type tea germplasm and landraces as a valuable resource for future tea breeding.

Schima is an ecologically and economically important woody genus in tea family (Theaceae). Unresolved species delimitations and phylogenetic relationships within Schima limit our understanding of the genus and hinder utilization of the genus for economic purposes. In the present study, we conducted comparative analysis among the complete chloroplast (cp) genomes of 11 Schima species. Our results indicate that Schima cp genomes possess a typical quadripartite structure, with conserved genomic structure and gene order. The size of the Schima cp genome is about 157 kilo base pairs (kb). They consistently encode 114 unique genes, including 80 protein-coding genes, 30 tRNAs, and 4 rRNAs, with 17 duplicated in the inverted repeat (IR). These cp genomes are highly conserved and do not show obvious expansion or contraction of the IR region. The percent variability of the 68 coding and 93 noncoding (>150 bp) fragments is consistently less than 3%. The seven most widely touted DNA barcode regions as well as one promising barcode candidate showed low sequence divergence. Eight mutational hotspots were identified from the 11 cp genomes. These hotspots may potentially be useful as specific DNA barcodes for species identification of Schima. The 58 cpSSR loci reported here are complementary to the microsatellite markers identified from the nuclear genome, and will be leveraged for further population-level studies. Phylogenetic relationships among the 11 Schima species were resolved with strong support based on the cp genome data set, which corresponds well with the species distribution pattern. The data presented here will serve as a foundation to facilitate species identification, DNA barcoding and phylogenetic reconstructions for future exploration of Schima.

Morphological and molecular evidence strongly supported the monophyly of tribe Anemoneae DC.; however, phylogenetic relationships among genera of this tribe have still not been fully resolved. In this study, we sampled 120 specimens representing 82 taxa of tribe Anemoneae. One nuclear ribosomal internal transcribed spacer (nrITS) and six plastid markers (atpB-rbcL, matK, psbA-trnQ, rpoB-trnC, rbcL and rps16) were amplified and sequenced. Both Maximum likelihood and Bayesian inference methods were used to reconstruct phylogenies for this tribe. Individual datasets supported all traditional genera as monophyletic, except Anemone and Clematis that were polyphyletic and paraphyletic, respectively, and revealed that the seven single-gene datasets can be split into two groups, i.e. nrITS + atpB-rbcL and the remaining five plastid markers. The combined nrITS + atpB-rbcL dataset recovered monophyly of subtribes Anemoninae (i.e. Anemone s.l.) and Clematidinae (including Anemoclema), respectively. However, the concatenated plastid dataset showed that one group of subtribes Anemoninae (Hepatica and Anemone spp. from subgenus Anemonidium) close to the clade Clematis s.l. + Anemoclema. Our results strongly supported a close relationship between Anemoclema and Clematis s.l., which included Archiclematis and Naravelia. Non-monophyly of Anemone s.l. using the plastid dataset indicates to revise as two genera, new Anemone s.l. (including Pulsatilla, Barneoudia, Oreithales and Knowltonia), Hepatica (corresponding to Anemone subgenus Anemonidium).

BACKGROUND: The karst regions in South China have an abundance of endemic plants that face high extinction risks. The Chinese Gesneriaceae endemic Paraisometrum mileense ( = Oreocharis mileensis), was presumed extinct for 100 years. After its re-discovery, the species has become one of five key plants selected by the Chinese forestry government to establish a new conservation category for plants with extremely small populations. For conservation purposes, we studied the phylogenetic and population genetic status of P. mileense at the three only known localities in Guangxi, Guizhou and Yunnan. METHODOLOGY/PRINCIPAL FINDINGS: We collected 64 samples (52 species) of Oreocharis and 8 samples from three provinces of P. mileense and generated molecular phylogenies, and inferred that P. mileense represents a relatively isolated and derived taxonomic unit within Oreocharis. Phylogeographic results of 104 samples of 12 populations of P. mileense indicated that the populations in Yunnan have derived from those in Guangxi and Guizhou. Based on AFLP data, the populations were found to harbor low levels of genetic diversity (He = 0.118), with no apparent gradient across the species' range, a restricted gene flow and significant isolation-by-distance with limited genetic differentiation among the populations across the three provinces (FST = 0.207, P

BackgroundCamellia, comprising more than 200 species, is a valuable economic commodity due to its enormously popular commercial products: tea leaves, flowers, and high-quality edible oils. It is the largest and most important genus in the family Theaceae. However, phylogenetic resolution of the species has proven to be difficult. Consequently, the interspecies relationships of the genus Camellia are still hotly debated. Phylogenomics is an attractive avenue that can be used to reconstruct the tree of life, especially at low taxonomic levels.Methodology/principal findingsSeven complete chloroplast (cp) genomes were sequenced from six species representing different subdivisions of the genus Camellia using Illumina sequencing technology. Four junctions between the single-copy segments and the inverted repeats were confirmed and genome assemblies were validated by PCR-based product sequencing using 123 pairs of primers covering preliminary cp genome assemblies. The length of the Camellia cp genome was found to be about 157kb, which contained 123 unique genes and 23 were duplicated in the IR regions. We determined that the complete Camellia cp genome was relatively well conserved, but contained enough genetic differences to provide useful phylogenetic information. Phylogenetic relationships were analyzed using seven complete cp genomes of six Camellia species. We also identified rapidly evolving regions of the cp genome that have the potential to be used for further species identification and phylogenetic resolution.Conclusions/significanceIn this study, we wanted to determine if analyzing completely sequenced cp genomes could help settle these controversies of interspecies relationships in Camellia. The results demonstrate that cp genome data are beneficial in resolving species definition because they indicate that organelle-based "barcodes", can be established for a species and then used to unmask interspecies phylogenetic relationships. It reveals that phylogenomics based on cp genomes is an effective approach for achieving phylogenetic resolution between Camellia species.