Hybridization and cryptic speciation in the Iberian endemic plant genus Phalacrocarpum (Asteraceae-Anthemideae)

Plastome phylogenomics and morphological traits analyses provide new insights into the phylogenetic position, species delimitation and speciation of Triplostegia (Caprifoliaceae)

BACKGROUND

The genus Triplostegia contains two recognized species, T. glandulifera and T. grandiflora, but its phylogenetic position and species delimitation remain controversial. In this study, we assembled plastid genomes and nuclear ribosomal DNA (nrDNA) cistrons sampled from 22 wild Triplostegia individuals, each from a separate population, and examined these with 11 recently published Triplostegia plastomes. Morphological traits were measured from herbarium specimens and wild material, and ecological niche models were constructed.

RESULTS

Triplostegia is a monophyletic genus within the subfamily Dipsacoideae comprising three monophyletic species, T. glandulifera, T. grandiflora, and an unrecognized species Triplostegia sp. A, which occupies much higher altitude than the other two. The new species had previously been misidentified as T. glandulifera, but differs in taproot, leaf, and other characters. Triplotegia is an old genus, with stem age 39.96 Ma, and within it T. glandulifera diverged 7.94 Ma. Triplostegia grandiflora and sp. A diverged 1.05 Ma, perhaps in response to Quaternary climate fluctuations. Niche overlap between Triplostegia species was positively correlated with their phylogenetic relatedness.

CONCLUSIONS

Our results provide new insights into the species delimitation of Triplostegia, and indicate that a taxonomic revision of Triplostegia is needed. We also identified that either rpoB-trnC or ycf1 could serve as a DNA barcode for Triplostegia.

Chloroplast Genomes and Phylogenetic Analysis of Three Carthamus (Asteraceae) Species

The genus Carthamus Linnaeus, which belongs to the tribe Cardueae in the Asteraceae family, originated in the Mediterranean region and consists of approximately 20 species worldwide. Understanding the phylogeny of the Carthamus is crucial for the cultivation of C. tinctorius. Although chloroplast genomes are widely used for species identification and evolutionary studies, there have been limited investigations on the chloroplast genomes of Carthamus species. In this study, we assembled the chloroplast genomes of C. persicus, C. tinctorius × C. persicus, and C. lanatus and combined them with the five chloroplast genomes of C. tinctorius for comparative genomic analysis. The sizes of the chloroplast genomes of C. lanatus, C. persicus, and C. tinctorius × C. persicus were 152,602 bp, 153,177 bp, and 153,177 bp, respectively. Comparative analysis showed that the chloroplast genome structures of the four Carthamus species were highly conserved. Additionally, the phylogenomic analysis demonstrated that the plastid genome and angiosperms353 dataset significantly improved the phylogenetic support of Carthamus species. This analysis supported Carthamus as a monophyletic taxon and its internal division into the sect. Carthamus and sect. Atractylis. The Carthamus was closely related to Carduncellus, Femeniasia, Phonus, and Centaurea. In conclusion, this study not only expands our understanding of the cp genomes of Carthamus species but also provides support for more comprehensive phylogenetic studies of Carthamus.

The genus Chrysanthemum: Phylogeny, biodiversity, phytometabolites, and chemodiversity

The ecologically and economically important genus Chrysanthemum contains around 40 species and many hybrids and cultivars. The dried capitulum of Chrysanthemum morifolium (CM) Ramat. Tzvel, i.e., Flos Chrysanthemi, is frequently used in traditional Chinese medicine (TCM) and folk medicine for at least 2,200 years. It has also been a popular tea beverage for about 2,000 years since Han Dynasty in China. However, the origin of different cultivars of CM and the phylogenetic relationship between Chrysanthemum and related Asteraceae genera are still elusive, and there is a lack of comprehensive review about the association between biodiversity and chemodiversity of Chrysanthemum. This article aims to provide a synthetic summary of the phylogeny, biodiversity, phytometabolites and chemodiversity of Chrysanthemum and related taxonomic groups, focusing on CM and its wild relatives. Based on extensive literature review and in light of the medicinal value of chrysanthemum, we give some suggestions for its relationship with some genera/species and future applications. Mining chemodiversity from biodiversity of Chrysanthemum containing subtribe Artemisiinae, as well as mining therapeutic efficacy and other utilities from chemodiversity/biodiversity, is closely related with sustainable conservation and utilization of Artemisiinae resources. There were eight main cultivars of Flos Chrysanthemi, i.e., Hangju, Boju, Gongju, Chuju, Huaiju, Jiju, Chuanju and Qiju, which differ in geographical origins and processing methods. Different CM cultivars originated from various hybridizations between multiple wild species. They mainly contained volatile oils, triterpenes, flavonoids, phenolic acids, polysaccharides, amino acids and other phytometabolites, which have the activities of antimicrobial, anti-viral, antioxidant, anti-aging, anticancer, anti-inflammatory, and closely related taxonomic groups could also be useful as food, medicine and tea. Despite some progresses, the genetic/chemical relationships among varieties, species and relevant genera have yet to be clarified; therefore, the roles of pharmacophylogeny and omics technology are highlighted.