Jipei Yue

Molecular phylogeny of Solms-laubachia (Brassicaceae) s.l., based on multiple nuclear and plastid DNA sequences, and its biogeographic implications

Abstract  The Hengduan Mountains region of south‐west China is a noted biodiversity hotspot, but the geographic origins and historical assembly of its rich endemic flora, including the sky‐island species of Solms‐laubachia Muschl. (Brassicaceae), have been little studied. Previous molecular studies on the phylogeny of Solms‐laubachia showed it to be paraphyletic, leading to considerable expansion not only of its taxonomic limits, but also its geographic range, with the inclusion of taxa from outside the Hengduan region. However, these studies provided little resolution of interspecific relationships, preventing inferences about historical biogeography within the clade. In the present study, new sequence data from two nuclear genes (LEAFY and G3pdh) and two chloroplast intergenic spacers (petN–psbM and psbM–trnD) were combined with existing markers to increase phylogenetic signals. Phaeonychium villosum (Maxim.) Al‐Shehbaz was found to be nested within Solms‐laubachia s.l. In general, phylogenetic relationships appear to be a good predictor of geography, with the Hengduan Mountain endemics embedded in a paraphyletic grade of species from the western Himalayas and central Asia, but they also imply morphological homoplasy. Incongruence was detected between the nuclear and chloroplast gene trees, perhaps resulting from incomplete lineage sorting of ancestral polymorphisms. The crown age of Solms‐laubachia s.l. was estimated to be approximately 1.42–3.68 mya, using Bayesian relaxed molecular clock analysis. Historical biogeographic analysis using a parametric dispersal–extinction–cladogenesis model inferred central Asia and the western Himalayas as most probable ancestral range of Solms‐laubachia s.l., and estimated higher rates of eastward expansion than westward during the diversification of descendant lineages. In summary, our results suggest that Solms‐laubachia s.l. originated during the Pliocene in central Asia, and subsequently migrated eastward into the Hengduan Mountains, colonizing sky‐island, alpine scree‐slope habitats that may have provided novel ecological opportunity and accelerated speciation, ultimately establishing this region as the present center of diversity of the genus.

Support for an expanded Solms-laubachia (Brassicaceae) : Evidence from sequences of chloroplast and nuclear genes

Abstract Sequences of the plastid maturase (matK) and nuclear chalcone synthase (Chs) were analyzed separately and in combination to assess phylogenetic relationships of Solms-laubachia Muschl. (all nine known species and two undescribed ones) to the genera Baimashania Al-Shehbaz, Parrya R. Br., Desideria Pamp., Leiospora (C. A. Mey.) Dvořák, Christolea Cambess., and Phaeonychium O. E. Schulz (Brassicaceae). Baimashania is clustered with Aubrieta deltoidea (L.) DC. and Arabis blepharophylla Hook. & Arn. Solms-laubachia, Desideria, Leiospora, Christolea, and Phaeonychium are more closely related to Matthiola R. Br. than to Parrya, and they form a well-supported clade. Within this clade, Leiospora is sister to a subclade containing the sister groups Christolea and Solms-laubachia s.l. The Solms-laubachia s.l. group contains Solms-laubachia, Desideria, and a species of Phaeonychium. Neither Solms-laubachia nor Desideria is monophyletic, whereas Phaeonychium jafrii Al-Shehbaz is embedded within the group. Therefore, our results suggest that Solms-laubachia be expanded to include Desideria and P. jafrii. Nevertheless, more species of Desideria, Parrya, and Phaeonychium are needed to further test our findings.

PHYLOGENETICS OF ACER (ACEROIDEAE, SAPINDACEAE) BASED ON NUCLEOTIDE SEQUENCES OF TWO CHLOROPLAST NON-CODING REGIONS

ABSTRACT Acer is one of the most diverse woody genera in the Northern Hemisphere. Recent phylogenetic studies support the placement of Acer and Dipteronia—sole members of the traditional Aceraceae—in the Sapindaceae. However, the monophyly of Acer and its sections remain to be tested. In this study, sequences of two chloroplast non-coding regions, psbM-trnD and trnD-trnT, are used to elucidate phylogenetic relationships of Acer and Dipteronia. Our results support the monophyly of Acer and sects. Arguta, Ginnala, Integrifolia, Lithocarpa, Macrantha, Palmata, Platanoidea, and Trifoliata. In contrast, sects. Acer, Goniocarpa, Parviflora, Saccharodendron, and Spicata are not monophyletic. Acer trautvetteri and A. opalus of sect. Acer are more closely related to A. monspessulanum of sect. Goniocarpa and A. saccharum of sect. Saccharina than to A. caesium and A. pseudoplatanus of sect. Acer. Acer distylium of sect. Parviflora is more closely related to sect. Platanoidea than to A. nipponicum of sect. Parviflora. Morphological species pairs between eastern Asia and North America are not sister species, including A. pycnanthum—A. rubrum and A. caudatum—A. spicatum. Acer ukurunduense is a distinct species from A. caudatum. Acer glabrum is most closely related to A. pseudoplatanus, whereas A. spicatum may be more closely related to A. carpinifolium than to A. caudatum. Section Hyptiocarpa is most closely related to sect. Rubra, and the two North American species of sect. Rubra (A. rubrum and A. saccharinum) are more closely related to each other than they are to the Japanese species (A. pycnanthum). Sections Integrifolia and Trifoliata are closely related, and so are Cissifolia and Arguta. Nevertheless, more data are needed to fully resolve intersectional relationships of Acer.

A synopsis of an expanded Solms-laubachia (Brassicaceae), and the description of four new species from Western China

Abstract Sequence data from the nuclear ribosomal ITS region and the chloroplast trnL-F were used to examine the generic delimitations of Solms-laubachia Muschl., Christolea Cambess., Desideria Pamp., Leiospora (C. A. Mey.) F. Dvořák, and Phaeonychium O. E. Schulz. Solms-laubachia, Desideria, and P. jafrii Al-Shehbaz formed a well-supported monophyletic clade, with Christolea as sister group. However, both Solms-laubachia and Desideria were polyphyletic, as they appeared in more than two positions in that clade, within which P. jafrii was embedded. The results are consistent with those based on sequences of plastid maturase (matK) and the nuclear chalcone synthase (Chs). SEM survey further reveals that the seed epidermis micromorphology of D. baiogoinensis (K. C. Kuan & C. H. An) Al-Shehbaz is most similar to that of S. lanata Botsch. Based on these findings, a comprehensive synopsis of an expanded Solms-laubachia with 26 species is presented; all species of Desideria and P. jafrii are transferred to Solms-laubachia resulting in 12 new combinations: S. baiogoinensis (K. C. Kuan & C. H. An) J. P. Yue, Al-Shehbaz & H. Sun, S. flabellata (Regel) J. P. Yue, Al-Shehbaz & H. Sun, S. haranensis (Al-Shehbaz) J. P. Yue, Al-Shehbaz & H. Sun, S. himalayensis (Cambess.) J. P. Yue, Al-Shehbaz & H. Sun, S. incana (Ovcz.) J. P. Yue, Al-Shehbaz & H. Sun, S. jafrii (Al-Shehbaz) J. P. Yue, Al-Shehbaz & H. Sun, S. linearis (N. Busch) J. P. Yue, Al-Shehbaz & H. Sun, S. mieheorum (Al-Shehbaz) J. P. Yue, Al-Shehbaz & H. Sun, S. mirabilis (Pamp.) J. P. Yue, Al-Shehbaz & H. Sun, S. nepalensis (H. Hara) J. P. Yue, Al-Shehbaz & H. Sun, S. prolifera (Maxim.) J. P. Yue, Al-Shehbaz & H. Sun, and S. stewartii (T. Anderson) J. P. Yue, Al-Shehbaz & H. Sun. Furthermore, four new species of Solms-laubachia are described from western China: S. angustifolia J. P. Yue, Al-Shehbaz & H. Sun, S. grandiflora J. P. Yue, Al-Shehbaz & H. Sun, and S. sunhangiana J. P. Yue & Al-Shehbaz (all from Sichuan Province), and S. calcicola J. P. Yue, Al-Shehbaz & H. Sun (from Xizang). Both S. linearifolia (W. W. Sm.) O. E. Schulz and S. mirabilis are lectotypified.

Molecular phylogeny reveals the non-monophyly of tribe Yinshanieae (Brassicaceae) and description of a new tribe, Hillielleae.

The taxonomic treatment within the unigeneric tribe Yinshanieae (Brassicaceae) is controversial, owing to differences in generic delimitation applied to its species. In this study, sequences from nuclear ITS and chloroplast trnL-F regions were used to test the monophyly of Yinshanieae, while two nuclear markers (ITS, ETS) and four chloroplast markers (trnL-F, trnH-psbA, rps16, rpL32-trnL) were used to elucidate the phylogenetic relationships within the tribe. Using maximum parsimony, maximum likelihood, and Bayesian inference methods, we reconstructed the phylogeny of Brassicaceae and Yinshanieae. The results show that Yinshanieae is not a monophyletic group, with the taxa splitting into two distantly related clades: one clade contains four taxa and falls in Lineage I, whereas the other includes all species previously placed in Hilliella and is embedded in the Expanded Lineage II. The tribe Yinshanieae is redefined, and a new tribe, Hillielleae, is proposed based on combined evidence from molecular phylogeny, morphology, and cytology.

New insights into the taxonomy of tribe Euclidieae (Brassicaceae), evidence from nrITS sequence data

Abstract As currently delimitated, the species-rich mustard tribe Euclidieae DC. (Brassicaceae) comprises 28 genera and 152 species distributed primarily in Asia. To date, no tribe-wide comprehensive phylogenetic analysis has been conducted. In this study, sequence data from the nuclear ribosomal internal transcribed spacer (nrITS) region of 82 species in all 28 genera of Euclidieae were used to test its monophyly and infer inter- and intra-generic relationships within. Phylogenetic analyses revealed that Rhammatophyllum and Sisymbriopsis are embedded within Solms-laubachia s.l., and Solms-laubachia lanuginosa (Eurycarpus lanuginosus) fell outside the tribe. Therefore, Solms-laubachia s.l. as currently recognized is not monophyletic and its generic delimitation needed further study. Besides, our results suggest that the genera Lepidostemon, Neotorularia, and Tetracme are polyphyletic.

Ten microsatellite loci from Solms-laubachia eurycarpa (Brassicaceae)

Solms‐laubachia eurycarpa is a medicinal herb endemic to the Hengduan Mountains region of south‐central China. We screened a partial genomic library enriched for microsatellites and characterized 10 polymorphic loci for S. eurycarpa. The number of alleles per locus ranged from five to 15, with an average of 9.6. The observed and expected heterozygosities ranged from 0.2 to 0.725 and from 0.585 to 0.871, respectively. Amplification in closely related taxa was successful for most loci. The results indicate significant potential for the utility of these markers in studying the population genetics of S. eurycarpa and related species.