The Complete Chloroplast Genome Sequence of Eupatorium fortunei: Genome Organization and Comparison with Related Species.

Eupatorium fortunei Turcz, a perennial herb of the Asteraceae family, is one of the horticultural and medicinal plants used for curing various diseases and is widely distributed in China and other Asian countries. It possesses antibacterial, antimetastatic, antiangiogenic, and antioxidant properties along with anticancer potential. However, the intrageneric classification and phylogenetic relationships within Eupatorium have long been controversial due to the lack of high-resolution molecular markers, and the complete chloroplast (cp) genome sequencing has not been reported with new evolutionary insights. In the present study, E. fortunei was used as an experimental material, and its genome was sequenced using high-throughput sequencing technology. We assembled the complete cp genome, and a systematic analysis was conducted for E. fortunei, acquiring the correspondence of its NCBI accession number (OK545755). The results showed that the cp genome of E. fortunei is a typical tetrad structure with a total length of 152,401 bp, and the genome encodes 133 genes. Analysis of the complete cp genomes of 20 Eupatorieae shows that the number of simple sequence repeats (SSRs) ranged from 19 to 36 while the number of long sequence repeats was 50 in all cases. Eleven highly divergent regions were identified and are potentially useful for the DNA barcoding of Eupatorieae. Phylogenetic analysis among 22 species based on protein-coding genes strongly supported that E. fortunei is more closely related to Praxelis clematidea and belongs to the same branch. The genome assembly and analysis of the cp genome of E. fortunei will facilitate the identification, taxonomy, and utilization of E. fortunei as well as provide more accurate evidence for the taxonomic identification and localization of Asteraceae plants.

Potentially toxic pyrrolizidine alkaloids in Eupatorium perfoliatum and three related species. Implications for herbal use as boneset.

INTRODUCTION: Pro-toxic dehydropyrrolizidine alkaloids are associated with liver disease in humans. The potential for long-term, low-level or intermittent exposures to cause or contribute to chronically-developing diseases is of international concern. Eupatorium perfoliatum is a medicinal herb referred to as boneset. While the presence of dehydropyrrolizidine alkaloids in some Eupatorium species is well-established, reports on Eupatorium perfoliatum are scant and contradictory. OBJECTIVE: To investigate the presence of dehydropyrrolizidine alkaloids in a survey of boneset samples and related alcoholic tinctures, and hot water infusions and decoctions. METHODS: Methanol, hot water or aqueous ethanol extracts of Eupatorium perfoliatum and three closely-related species were subjected to HPLC-ESI(+)MS and MS/MS analysis using three complementary column methods. Dehydropyrrolizidine alkaloids were identified from their MS data and comparison with standards. RESULTS: Forty-nine samples of Eupatorium perfoliatum were shown to contain dehydropyrrolizidine alkaloids (0.0002-0.07% w/w), the majority dominated by lycopsamine and intermedine, their N-oxides and acetylated derivatives. Alcoholic tinctures and hot water infusions and decoctions had high concentrations of the alkaloids. Different chemotypes, hybridisation or contamination of some Eupatorium perfoliatum samples with related species were suggested by the co-presence of retronecine- and heliotridine-based alkaloids. CONCLUSIONS: Sampling issues, low and high alkaloid chemotypes of Eupatorium perfoliatum or interspecies hybridization could cause the wide variation in dehydropyrrolizidine alkaloid concentrations or the different profiles observed. Concerns associated with dehydropyrrolizidine alkaloids provide a compelling reason for preclusive caution until further research can better define the toxicity and carcinogenicity of the dehydropyrrolizidine alkaloid content of Eupatorium perfoliatum. [Correction added on 12 July 2018, after first online publication: The 'Conclusions' section in the abstract has been added.].

Complete chloroplast genome sequences of Praxelis (Eupatorium catarium Veldkamp), an important invasive species.

Praxelis (Eupatorium catarium Veldkamp) is a new hazardous invasive plant species that has caused serious economic losses and environmental damage in the Northern hemisphere tropical and subtropical regions. Although previous studies focused on detecting the biological characteristics of this plant to prevent its expansion, little effort has been made to understand the impact of Praxelis on the ecosystem in an evolutionary process. The genetic information of Praxelis is required for further phylogenetic identification and evolutionary studies. Here, we report the complete Praxelis chloroplast (cp) genome sequence. The Praxelis chloroplast genome is 151,410 bp in length including a small single-copy region (18,547 bp) and a large single-copy region (85,311 bp) separated by a pair of inverted repeats (IRs; 23,776 bp). The genome contains 85 unique and 18 duplicated genes in the IR region. The gene content and organization are similar to other Asteraceae tribe cp genomes. We also analyzed the whole cp genome sequence, repeat structure, codon usage, contraction of the IR and gene structure/organization features between native and invasive Asteraceae plants, in order to understand the evolution of organelle genomes between native and invasive Asteraceae. Comparative analysis identified the 14 markers containing greater than 2% parsimony-informative characters, indicating that they are potential informative markers for barcoding and phylogenetic analysis. Moreover, a sister relationship between Praxelis and seven other species in Asteraceae was found based on phylogenetic analysis of 28 protein-coding sequences. Complete cp genome information is useful for plant phylogenetic and evolutionary studies within this invasive species and also within the Asteraceae family.

Hybrid genera in Liatrinae (Asteraceae: Eupatorieae).

Liatrinae is a small subtribe of Eupatorieae that occurs in North America with a center of generic-level diversity in the southeastern United States. Molecular phylogenetic data were sought to assess whether two monotypic genera, Garberia and Hartwrightia, are accurately placed in the subtribe, and to resolve questions of the generic-level classification of Carphephorus. Phylogenetic analyses of nuclear ITS/ETS and plastid DNA data indicated that Garberia is the basalmost diverging lineage, and that Hartwrightia is phylogenetically embedded in the subtribe. There was significant incongruence between the ITS/ETS and plastid DNA datasets in the placement of Hartwrightia and another monotypic genus, Litrisa, suggesting that both are of original hybrid origin. The results also showed that Carphephorus s.l. is not monophyletic, and even after removal of the two species of Trilisa, it is still paraphyletic to Liatris. The apparent hybrid origin of Hartwrightia, which is morphologically transgressive relative to its inferred parental lineages, suggests that reticulation between phylogenetically distinct lineages may be a recurrent problem for phylogenetic estimation in Asteraceae.

Sesquiterpenoids isolated from Eupatorium glehnii. Isolation of guaiaglehnin A, structure revision of Hiyodorilactone B, and genetic comparison.

A new sesquiterpenoid substituted with unsaturated ester, guaiaglehnin A (1), along with 15 previously known compounds, were isolated from the methanol extract of the terrestrial part of Eupatorium glehnii (Compositae) collected in Nagano Prefecture, Japan, the results of which supported the previous study by Takahashi et al. The chemical constituents of E. glehnii collected in Nagano Prefecture and those collected in Tokushima or Hokkaido are quite different, depending on collection site, although the species are identical. The base sequences of three different samples were identical. Diversity in the chemical components was detected, though no diversity existed in the DNA sequence. In this study, eupasimplicin A (2) was also isolated, whose presence in the extract of E. chinense simplicifolium was recorded but not in an article. The side chain geometry of hiyodorilactone B (5) was revised to be E.

Polyphyletic origin of pyrrolizidine alkaloids within the Asteraceae. Evidence from differential tissue expression of homospermidine synthase.

The evolution of pathways within plant secondary metabolism has been studied by using the pyrrolizidine alkaloids (PAs) as a model system. PAs are constitutively produced by plants as a defense against herbivores. The occurrence of PAs is restricted to certain unrelated families within the angiosperms. Homospermidine synthase (HSS), the first specific enzyme in the biosynthesis of the necine base moiety of PAs, was originally recruited from deoxyhypusine synthase, an enzyme involved in the posttranslational activation of the eukaryotic initiation factor 5A. Recently, this gene recruitment has been shown to have occurred several times independently within the angiosperms and even twice within the Asteraceae. Here, we demonstrate that, within these two PA-producing tribes of the Asteraceae, namely Senecioneae and Eupatorieae, HSS is expressed differently despite catalyzing the same step in PA biosynthesis. Within Eupatorium cannabinum, HSS is expressed uniformly in all cells of the root cortex parenchyma, but not within the endodermis and exodermis. Within Senecio vernalis, HSS expression has been previously identified in groups of specialized cells of the endodermis and the adjacent root cortex parenchyma. This expression pattern was confirmed for Senecio jacobaea as well. Furthermore, the expression of HSS in E. cannabinum is dependent on the development of the plant, suggesting a close linkage to plant growth.