The chloroplast (cp) genome is useful in the study of phylogenomics, molecular dating, and molecular evolution. Gentiana sect. Kudoa is a predominantly alpine flowering plant that is valued for its contributions to medicine, ecology, and horticulture. Previous evolutionary studies showed that the plastid gene loss pattern and intra-sectional phylogenetics in sect. Kudoa are still unclear. In this study, we compared 11 Gentiana plastomes, including 7 newly sequenced plastomes from sect. Kudoa, to represent its three serious: ser. Ornatae, ser. Verticillatae, and ser. Monanthae. The cp genome sizes of the seven species ranged from 137,278 to 147,156 bp. The plastome size variation mainly occurred in the small single-copy and long single-copy regions rather than the inverted repeat regions. Compared with sect. Cruciata, the plastomes in ser. Ornatae and ser. Verticillatae had lost approximately 11 kb of sequences containing 11 ndh genes. Conversely, far fewer losses were observed in ser. Monanthae. The phylogenetic tree revealed that sect. Kudoa was not monophyletic and that ser. Monanthae was more closely related to other sections rather than sect. Kudoa. The molecular dating analysis indicated that ser. Monanthae and sect. Kudoa diverged around 8.23 Ma. In ser. Ornatae and ser. Verticillatae, the divergence occurred at around 0.07–1.78 Ma. The nucleotide diversity analysis indicated that the intergenic regions trnH-psbA, trnK-trnQ, ycf3-trnS and rpl32-trnL constituted divergence hotspots in both sect. Kudoa and Gentiana, and would be useful for future phylogenetic and population genetic studies.

The increasing availability of plastid genomes represents a new opportunity to explore molecular evolution in plants (Tonti-Filippini et al., 2017;Twyford & Ness, 2017). For example, plastid phylogenomics has resolved some persistent taxonomic uncertainties in challenging plant groups (e.g., in Rosaceae; Zhang et al., 2017), and more generally led to a better understanding of major events in plant

The lotus (Nelumbonaceae: Nelumbo Adans.) is a highly desired ornamental plant, comprising only two extant species, the sacred lotus (N. nucifera Gaerten.) with red flowers and the American lotus (N. lutea Willd.) with yellow flowers. Flower color is the most obvious difference of two species. To better understand the mechanism of flower color differentiation, the content of anthocyanins and the expression levels of four key structural genes (e.g., DFR, ANS, UFGT and GST) were analyzed in two species. Our results revealed that anthocyanins were detected in red flowers, not yellow flowers. Expression analysis showed that no transcripts of GST gene and low expression level of three UFGT genes were detected in yellow flowers. In addition, three regulatory genes (NnMYB5, NnbHLH1 and NnTTG1) were isolated from red flowers and showed a high similarity to corresponding regulatory genes of other species. Sequence analysis of MYB5, bHLH1 and TTG1 in two species revealed striking differences in coding region and promoter region of MYB5 gene. Population analysis identified three MYB5 variants in Nelumbo: a functional allele existed in red flowers and two inactive forms existed in yellow flowers. This result revealed that there was an association between allelic variation in MYB5 gene and flower color difference. Yeast two-hybrid experiments showed that NnMYB5 interacts with NnbHLH1, NlbHLH1 and NnTTG1, and NnTTG1 also interacts with NnbHLH1 and NlbHLH1. The over-expression of NnMYB5 led to anthocyanin accumulation in immature seeds and flower stalks and up-regulation of expression of TT19 in Arabidopsis. Therefore, NnMYB5 is a transcription activator of anthocyanin synthesis. This study helps to elucidate the function of NnMYB5 and will contribute to clarify the mechanism of flower coloration and genetic engineering of flower color in lotus.

Gentiana is a sub-cosmopolitan temperate genus among the most species-rich in Gentianaceae. Although molecular data (produced via Sanger sequencing) allowed the resolution of phylogenetic relationships between Gentiana and other genera in subtribe Gentianinae, the validity of sections within the genus remains largely untested. In this study, we evaluated the monophyly of all 14 sections attributed to Gentiana, using 294 unlinked anchored loci, the nuclear ribosomal DNA (rDNA) cistron as well as plastid genomes, all produced by anchored hybrid enrichment. We reconstructed phylogenetic relationships by conducting maximum likelihood and Bayesian analyses. These analyses represent a significant improvement over previous taxonomic studies using molecular tools. Our results partly correspond to traditional taxonomic treatments, with several sections being well supported as monophyletic, including Gentiana sect. Calathianae, sect. Ciminalis, sect. Cruciata, sect. Frigida, sect. Gentiana and sect. Pneumonanthe. In contrast, G. sect. Isomeria, sect. Microsperma and sect. Monopodiae were found to be polyphyletic, whereas sect. Dolichocarpa and sect. Fimbricorona were nested within sect. Chondrophyllae. We here provide new taxonomic treatments for these sections, mostly based upon the traditional delineation of their series, which were recovered as monophyletic. In our new treatment, Gentiana encompasses 13 sections. A new determination key to the sections of Gentiana is provided.

Background and Aims Hosting several global biodiversity hotspots, the region of the Qinghai-Tibetan Plateau (QTP) is exceptionally species-rich and harbours a remarkable level of endemism. Yet, despite a growing number of studies, factors fostering divergence, speciation and ultimately diversity remain poorly understood for QTP alpine plants. This is particularly the case for the role of hybridization. Here, we explored the evolutionary history of three closely related Gentiana endemic species, and tested whether our results supported the mountain geo-biodiversity hypothesis (MGH). Methods We genotyped 69 populations across the QTP with one chloroplast marker and 12 nuclear microsatellite loci. We performed phylogeographical analysis, Bayesian clustering, approximate Bayesian computation and principal components analysis to explore their genetic relationship and evolutionary history. In addition, we modelled their distribution under different climates. Key Results Each species was composed of two geographically distinct clades, corresponding to the south-eastern and north-western parts of their distribution. Thus Gentiana veitchiorum and G. lawrencei var. farreri, which diverged recently, appear to have shared at least refugia in the past, from which their range expanded later on. Indeed, climatic niche modelling showed that both species went through continuous expansion from the Last Interglacial Maximum to the present day. Moreover, we have evidence of hybridization in the northwest clade of G. lawrencei var. farreri, which probably occurred in the refugium located on the plateau platform. Furthermore, phylogenetic and population genetic analyses suggested that G. dolichocalyx should be a geographically limited distinct species with low genetic differentiation from G. lawrencei var. farreri. Conclusions Climatic fluctuations in the region of the QTP have played an important role in shaping the current genetic structure of G. lawrencei var. farreri and G. veitchiorum. We argue that a species pump effect did occur prior to the Last Interglacial Maximum, thus lending support to the MGH. However, our results do depart from expectations as suggested in the MGH for more recent distribution range and hybridization dynamics.

BackgroundThe Qinghai-Tibetan Plateau (QTP) is one of the most extensive habitats for alpine plants in the world. Climatic oscillations during the Quaternary ice age had a dramatic effect on species ranges on the QTP and the adjacent areas. However, how the distribution ranges of aquatic plant species shifted on the QTP in response to Quaternary climatic changes remains almost unknown.Methodology and Principal FindingsWe studied the phylogeography and demographic history of the widespread aquatic herb Hippuris vulgaris from the QTP and adjacent areas. Our sampling included 385 individuals from 47 natural populations of H. vulgaris. Using sequences from four chloroplast DNA (cpDNA) non-coding regions, we distinguished eight different cpDNA haplotypes. From the cpDNA variation in H. vulgaris, we found a very high level of population differentiation (G ST = 0.819) but the phylogeographical structure remained obscure (N ST = 0.853>G ST = 0.819, P>0.05). Phylogenetic analyses revealed two main cpDNA haplotype lineages. The split between these two haplotype groups can be dated back to the mid-to-late Pleistocene (ca. 0.480 Myr). Mismatch distribution analyses showed that each of these had experienced a recent range expansion. These two expansions (ca. 0.12 and 0.17 Myr) might have begun from the different refugees before the Last Glacial Maximum (LGM).Conclusions/SignificanceThis study initiates a research on the phylogeography of aquatic herbs in the QTP and for the first time sheds light on the response of an alpine aquatic seed plant species in the QTP to Quaternary climate oscillations.

ABSTRACT. To assess the genetic status of this species, the genetic diversity of wild Macrobrachium nipponense from seven geographic locations in the Yellow River basin were investigated using 20 polymorphic microsatellite DNA loci. The genetic diversity between populations was indicated by the mean number of alleles per locus and mean observed heterozygosity (H) and the expected H, which was arranged from 2 to 10, from 0.4705 to 0.5731, and from 0.5174 to 0.6146, respectively. Hardy-Weinberg equilibrium analysis indicated that a deficiency of heterozygotes existed in all seven populations. Both the F ST and AMOVA analyses showed that there is significant difference on population differentiation among populations. The UPGMA clustering tree demonstrated that their close relationship is consistent with their geographic proximity. The Genetic diversity analysis of Oriental River Prawn data suggest that this Yellow River population has a wide genetic base that is suitable for breeding.

Rhododendron (Ericaceae) encompasses some of the most important horticultural and ornamental plant species in the world (Dunemann et al., 1999;Väinölä, 2000). It is a large and diverse genus widespread across Europe, Asia and North America (Irving & Hebda, 1993).Rhododendron species are renowned for their extensive phenotypic variability and plasticity, conferring wide range of habitats (Cox, 1990;Gibbs et al., 2011;Liang & Eckstein, 2009). Rhododendron species are widely used as traditional treatments for gastrointestinal, cold, asthma, inflammation, oxidative stress, pain and skin diseases