Molecular Phylogenetics of Phyllanthaceae: Evidence from Plastid MatK and Nuclear PHYC Sequences

Plastid matK and a fragment of the low-copy nuclear gene PHYC were sequenced for 30 genera of Phyllanthaceae to evaluate tribal and generic delimitation. Resolution and bootstrap percentages obtained with matK are higher than that of PHYC but both regions show nearly identical phylogenetic patterns. Phylogenetic relationships inferred from the independent and combined data are congruent and differ from previous, morphology-based classifications but are highly concordant with those of the plastid gene rbcL previously published. Phyllanthaceae is monophyletic and gives rise to two well-resolved clades (T and F) that could be recognized as subfamilies. DNA sequence data for Keayodendron and Zimmermanniopsis are presented for the first time. Keayodendron is misplaced in tribe Phyllantheae and belongs to the Bridelia alliance. Zimmermanniopsis is sister to Zimmermannia. Phyllanthus and Cleistanthus are paraphyletic. Savia and Phyllanthus subgenus Kirganelia are not monophyletic.Organismic and Evolutionary Biolog

Molecular phylogeny of Nassauvia (Asteraceae, Mutisieae) based on nrDNA ITS sequences

The phylogeny of the genus Nassauvia and closely related genera was reconstructed using sequences from the internal transcribed spacer regions (ITS) of nuclear ribosomal DNA. The genus Triptilion is nested within Nassauvia, making the latter genus paraphyletic. Neither of the two subgenera Nassauvia and Strongyloma is resolved as monophyletic, and none of the sections of subgenus Nassauvia is recovered as monophyletic. The evolution of the compound secondary inflorescences has been complex in Nassauvia, with the highly aggregated forms representing the original condition in the genus. However, the ancestral condition is equivocal in several clades, and there are alternative reconstructions for the gains?losses of the variously aggregated conditions. There has been at least one gain of solitary capitula in Nassauvia. The evolution of flavonoid chemistry has been complex in Nassauvia, and flavonoids are of limited phylogenetictaxonomic utility in the genus. Gains?losses of flavonols occur only on terminals whereas changes in flavones and C-glycosyl flavones occur at various levels in the tree. Gains?losses of methylation of flavones and flavonols occur only on terminals.Nassauvia and closely related genera was reconstructed using sequences from the internal transcribed spacer regions (ITS) of nuclear ribosomal DNA. The genus Triptilion is nested within Nassauvia, making the latter genus paraphyletic. Neither of the two subgenera Nassauvia and Strongyloma is resolved as monophyletic, and none of the sections of subgenus Nassauvia is recovered as monophyletic. The evolution of the compound secondary inflorescences has been complex in Nassauvia, with the highly aggregated forms representing the original condition in the genus. However, the ancestral condition is equivocal in several clades, and there are alternative reconstructions for the gains?losses of the variously aggregated conditions. There has been at least one gain of solitary capitula in Nassauvia. The evolution of flavonoid chemistry has been complex in Nassauvia, and flavonoids are of limited phylogenetictaxonomic utility in the genus. Gains?losses of flavonols occur only on terminals whereas changes in flavones and C-glycosyl flavones occur at various levels in the tree. Gains?losses of methylation of flavones and flavonols occur only on terminals.Fil: Maraner, Fabrizio. Universidad de Viena; AustriaFil: Samuel, Rosabelle. Universidad de Viena; AustriaFil: Stuessy, Tod F.. Universidad de Viena; AustriaFil: Crawford, Daniel J.. University of Kansas; Estados UnidosFil: Crisci, Jorge Victor. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División de Plantas Vasculares; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Pandey, A.. University Of Delhi; IndiaFil: Mort, Mark E.. University of Kansas; Estados Unido

Molecular phylogeny of <i>Nassauvia</i> (Asteraceae, Mutisieae) based on nrDNA ITS sequences

The phylogeny of the genus Nassauvia and closely related genera was reconstructed using sequences from the internal transcribed spacer regions (ITS) of nuclear ribosomal DNA. The genus Triptilion is nested within Nassauvia, making the latter genus paraphyletic. Neither of the two subgenera Nassauvia and Strongyloma is resolved as monophyletic, and none of the sections of subgenus Nassauvia is recovered as monophyletic. The evolution of the compound secondary inflorescences has been complex in Nassauvia, with the highly aggregated forms representing the original condition in the genus. However, the ancestral condition is equivocal in several clades, and there are alternative reconstructions for the gains–losses of the variously aggregated conditions. There has been at least one gain of solitary capitula in Nassauvia. The evolution of flavonoid chemistry has been complex in Nassauvia, and flavonoids are of limited phylogenetic-taxonomic utility in the genus. Gains–losses of flavonols occur only on terminals whereas changes in flavones and C-glycosyl flavones occur at various levels in the tree. Gains–losses of methylation of flavones and flavonols occur only on terminals.Facultad de Ciencias Naturales y Muse

Plant DNA barcodes and assessment of phylogenetic community structure of a tropical mixed dipterocarp forest in Brunei Darussalam (Borneo)

DNA barcoding is a fast and reliable tool to assess and monitor biodiversity and, via community phylogenetics, to investigate ecological and evolutionary processes that may be responsible for the community structure of forests. In this study, DNA barcodes for the two widely used plastid coding regions rbcL and matK are used to contribute to identification of morphologically undetermined individuals, as well as to investigate phylogenetic structure of tree communities in 70 subplots (10 × 10m) of a 25-ha forest-dynamics plot in Brunei (Borneo, Southeast Asia). The combined matrix (rbcL + matK) comprised 555 haplotypes (from ≥154 genera, 68 families and 25 orders sensu APG, Angiosperm Phylogeny Group, 2016), making a substantial contribution to tree barcode sequences from Southeast Asia. Barcode sequences were used to reconstruct phylogenetic relationships using maximum likelihood, both with and without constraining the topology of taxonomic orders to match that proposed by the Angiosperm Phylogeny Group. A third phylogenetic tree was reconstructed using the program Phylomatic to investigate the influence of phylogenetic resolution on results. Detection of non-random patterns of community assembly was determined by net relatedness index (NRI) and nearest taxon index (NTI). In most cases, community assembly was either random or phylogenetically clustered, which likely indicates the importance to community structure of habitat filtering based on phylogenetically correlated traits in determining community structure. Different phylogenetic trees gave similar overall results, but the Phylomatic tree produced greater variation across plots for NRI and NTI values, presumably due to noise introduced by using an unresolved phylogenetic tree. Our results suggest that using a DNA barcode tree has benefits over the traditionally used Phylomatic approach by increasing precision and accuracy and allowing the incorporation of taxonomically unidentified individuals into analyses

Sequencing of whole plastid genomes and nuclear ribosomal DNA of Diospyros species (Ebenaceae) endemic to New Caledonia: many species, little divergence

International audienceBackground and Aims: Some plant groups, especially on islands, have been shaped by strong ancestral bottlenecks and rapid, recent radiation of phenotypic characters. Single molecular markers are often not informative enough for phylogenetic reconstruction in such plant groups. Whole plastid genomes and nuclear ribosomal DNA (nrDNA) are viewed by many researchers as sources of information for phylogenetic reconstruction of groups in which expected levels of divergence in standard markers are low. Here we evaluate the usefulness of these data types to resolve phylogenetic relationships among closely related Diospyros species.Methods: Twenty-two closely related Diospyros species from New Caledonia were investigated using whole plastid genomes and nrDNA data from low-coverage next-generation sequencing (NGS). Phylogenetic trees were inferred using maximum parsimony, maximum likelihood and Bayesian inference on separate plastid and nrDNA and combined matrices.Key Results: The plastid and nrDNA sequences were, singly and together, unable to provide well supported phylogenetic relationships among the closely related New Caledonian Diospyros species. In the nrDNA, a 6-fold greater percentage of parsimony-informative characters compared with plastid DNA was found, but the total number of informative sites was greater for the much larger plastid DNA genomes. Combining the plastid and nuclear data improved resolution. Plastid results showed a trend towards geographical clustering of accessions rather than following taxonomic species.Conclusions: In plant groups in which multiple plastid markers are not sufficiently informative, an investigation at the level of the entire plastid genome may also not be sufficient for detailed phylogenetic reconstruction. Sequencing of complete plastid genomes and nrDNA repeats seems to clarify some relationships among the New Caledonian Diospyros species, but the higher percentage of parsimony-informative characters in nrDNA compared with plastid DNA did not help to resolve the phylogenetic tree because the total number of variable sites was much lower than in the entire plastid genome. The geographical clustering of the individuals against a background of overall low sequence divergence could indicate transfer of plastid genomes due to hybridization and introgression following secondary contact

Complex rearrangements are involved in Cephalanthera (Orchidaceae) chromosome evolution

The genus Cephalanthera is an excellent plant group for karyotype evolution studies because it exhibits a dysploid series and bimodal karyotypes. With the aim of understanding their chromosomal and phylogenetic relationships, rRNA genes and the Arabidopsis-type telomeric sequence were mapped by fluorescence in-situ hybridization (FISH), and the rDNA intergenic spacer (ITS) was sequenced for the first time in three European species: C. longifolia (2n = 4x = 32), C. damasonium (2n = 4x = 36) and C. rubra (2n = 4x = 44). One 45S and three 5S rDNA sites are observed in C. longifolia, one 45S and two 5S sites in C. damasonium, and two 45S and one 5S site in C. rubra. Telomeric signals were observed at every chromosome end in all three species and C. damasonium also displays interstitial signals on three chromosome pairs. In agreement with chromosome data, molecular analyses support C. longifolia and C. damasonium as closely related taxa, while C. rubra stands apart. Possible pathways of karyotype evolution are discussed in reference to a previous hypothesis. The results indicate that complex chromosomal rearrangements, possibly involving Robertsonian fusions and fissions, loss of telomeric repeats, gain or loss of rDNA sites and other heterochromatic sequences and inversions, may have contributed to generating the present-day karyotypes.Fil: Moscone, Eduardo Alberto. Universidad de Viena; Austria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Samuel, Rosabelle. Universidad de Viena; AustriaFil: Schwarzacher, Trude. University of Leicester; Reino UnidoFil: Schweizer, Dieter. Universidad de Viena; AustriaFil: Pedrosa-Harand, Andrea. Universidad de Viena; Austri

Molecular phylogeny helps to delimit <i>Plectranthus</i> <i>hadiensis</i> from its related morph occurring in Sri Lanka

Plectranthus hadiensis is an important medicinal plant in Sri Lanka. It was considered a separate species, P. zeylanicus, endemic to the island until its inclusion, as P. hadiensis var. tomentosus, together with morphs from southern Africa in the revised species concept of P. hadiensis. However, there are morphological, chemical, and therapeutic differences between the African and Sri Lankan morphs. We used eight molecular markers in a phylogenetic study to clarify the species concept of P. hadiensis and to investigate whether it should include the Sri Lankan morph. We examined the position of the two P. hadiensis morphs in relation to eight other Plectranthus species. The maximum likelihood tree revealed three clades: a weakly supported clade including P. calycinus, P. glabratus, P. fruticosus, and P. malabaricus; a highly supported clade including P. amboinicus and African and Sri Lankan specimens of P. hadiensis; and a highly supported clade formed by P. barbatus, P. caninus, and P. hadiensis var. tomentosus. The African P. hadiensis specimens form a highly supported subclade sister to a subclade containing the Sri Lankan P. hadiensis, suggesting that the subclades correspond to either two sister species or two subspecies. We propose that they are more likely to be sister species given the differences in morphology, chemistry, and chromosome number

Systematics and evolution of the Old World Ebenaceae, a review with emphasis on the large genus Diospyros and its radiation in New Caledonia

International audienceIn this review article, we provide an overview of the status of research on Old World Ebenaceae with an emphasis on the large genus Diospyros. The well-supported phylogenetic tree obtained from nucleotide sequences of multiple regions of plastid genome gave clear insights into the subfamilial classification of Ebenaceae. It supported inclusion of previously recognized genera such as Cargillia, Gunisanthus, Maba, Macreightia and Tetraclis in Diospyros. Endemic Diospyros spp. of New Caledonia have multiple origins. One of these clades has c. 21 species that are morphologically distinct and occupy different ecological niches, but they exhibit low genetic variation, leading to a lack of phylogenetic resolution. Analyses of whole plastid genome sequences did not greatly increase resolution or support for results of our previous plastid analyses. Geographical clustering of the individuals against a background of lower sequence divergence of the whole plastid genome could be due to transfer of plastid genomes during hybridization and introgression following secondary contact. However, &gt; 8400 filtered single nucleotide polymorphisms (SNPs) from restriction site associated DNA sequencing (RADseq) confirmed species circumscriptions for this clade and produced well-supported phylogenetic relationships, pointing to an early regional clustering among populations and species. This supported allopatric speciation with respect to macrohabitat (i.e. climatic conditions) having had a role in the initial differentiation in the group. A later, more rapid radiation involved divergence with respect to microhabitat (e.g. soil preference). Although chromosome counts indicate that Diospyros spp. are consistently diploids with 2n = 30, extensive variation in genome size has been observed, which is due to an increase of repeat elements, including LTR/gypsy. In Ebenaceae, pollen is heterogeneous, and palynological synapomorphies are traced at different taxonomic levels. Several new Diospyros spp. have recently been identified and documented from India, Thailand, China, Africa and New Caledonia. Taxonomic revisions have been completed for the Australian species, and synonyms are reported for some New Caledonian Diospyros spp

Dataset1

Dataset D

SupplTable1

Supplementary Table