Complex and reticulate origin of edible roses (Rosa, Rosaceae) in China

While roses are today among the most popular ornamental plants, the petals and fruits of some cultivars have flavored foods for millennia. The genetic origins of these edible cultivars remain poorly investigated. We collected the major varieties of edible roses available in China, assembled their plastome sequences, and phased the haplotypes for internal transcribed spacers (ITS1/ITS2) of the 18S-5.8S-26S nuclear ribosomal cistron. Our phylogenetic reconstruction using 88 plastid genomes, of primarily maternal origin, uncovered well-supported genetic relationships within Rosa, including all sections and all subgenera. We phased the ITS sequences to identify potential donor species ancestral to the development of known edible cultivars. The tri-parental Middle-Eastern origin of R. × damascena, the species most widely used in perfume products and food additives, was confirmed as a descendent of past hybridizations among R. moschata, R. gallica, and R. majalis/R. fedtschenkoana/R. davurica. In contrast, R. chinensis, R. rugosa, and R. gallica, in association with six other wild species, were the main donors for fifteen varieties of edible roses. The domesticated R. rugosa ‘Plena’ was shown to be a hybrid between R. rugosa and R. davurica, sharing a common origin with R. ‘Fenghua’. Only R. ‘Jinbian’ and R. ‘Crimson Glory’ featured continuous flowering. All remaining cultivars of edible roses bloomed only once a year. Our study provides important resources for clarifying the origin of edible roses and suggests a future for breeding new cultivars with unique traits, such as continuous flowering.

Plastome and Nuclear Phylogenies of Dwarf Mistletoes (Arceuthobium: Viscaceae)

Abstract— Dwarf mistletoes are a lineage of morphologically-reduced stem parasites inhabiting Pinaceae and Cupressaceae throughout the northern hemisphere and equatorial East Africa. Though diagnosable by a suite of morphological traits, phylogenetic knowledge of species relationships has been limited to studies employing either comprehensive taxonomic sampling of one or two genes, or more sequence data from a limited number of individuals. We used data from genome skimming to assemble 3kb of the nuclear ribosomal cistron and up to 45kb of the plastome to clarify the phylogenetic root of the genus, monophyly of species, and relationships among infraspecific taxa. Genomic differentiation among terminal taxa was variable; however, we found strong support for reciprocally monophyletic New World and Old World lineages, congruent nrDNA and plastome topologies at the species level and below, and monophyly of most taxonomic sections and species. Plastome gene content was stable across the genus with minimal pseudogenization or loss, as in other hemiparasites, with the notable exception of cemA. These findings form the basis of our re-evaluation of historical biogeographical hypotheses, species- and subspecies-level taxonomy, and plastome evolution in Arceuthobium. More broadly, this work provides a foundation for future clade-focused comparative and biosystematics studies of Arceuthobium.

Evolution of Poecilimon jonicus group (Orthoptera: Tettigoniidae): a history linked to the Aegean Neogene paleogeography

The Aegean archipelago is among the largest on Earth with astonishing biodiversity within Europe. Its territory underwent a massive geotectonic transformation in Neogene that resulted in multitude of changes in land-sea configuration and disintegrated the formerly united Aegean land to a complicated mainland-archipelago system. Therefore, it represents an excellent laboratory for studying evolution of terrestrial fauna. In the present study, we use a model group of flightless bush crickets with annual reproduction cycle—Poecilimon jonicus species group—to trace correlation of lineage diversification with the known paleogeographic events in the Aegean area. The group belongs to the hyperdiverse genus Poecilimon and has a disjunct distribution along the Hellenic arc from southwestern Anatolia through Crete to the western Balkans and the Apennines. To test our hypothesis, we inferred phylogenetic relationships of the P. jonicus group sensu lato using a nuclear fragment covering two spacers of the ribosomal cistron (ITS1 + ITS2). To study intra-group phylogeny, we compared mitochondrial phylogenies based on two matrices—(1) a concatenated ND2 and COI dataset of 1656 bp and (2) a 16S rRNA + 12S rRNA dataset of 1835 bp. As a second step, we estimated divergence times applying Bayesian approach with BEAST and a relative rate framework with RelTime on the mitochondrial matrices. We compare trees calibrated based on evolutionary rates and tectonic events and discuss radiation scenarios in concordance with known paleogeographic events in the Aegean area. Our results revealed robust phylogeny of the Poecilimon jonicus group and confirmed a strong link between its evolution and the Aegean paleogeography. The phylogenetic relationships of the group supported reconsideration of its systematics.

Genetic analysis confirms the presence of Dicrocoelium dendriticum in the Himalaya ranges of Pakistan

Lancet liver flukes of the genus Dicrocoelium (Trematoda: Digenea) are recognised parasites of domestic and wild herbivores. The aim of the present study was to address a lack of knowledge of lancet flukes in the Himalaya ranges of Pakistan by characterising Dicrocoelium species collected from the Chitral valley. The morphology of 48 flukes belonging to eight host populations was examined in detail and according to published keys, they were identified as either D. dendriticum or Dicrocoelium chinensis. PCR and sequencing of fragments of ribosomal cistron DNA, and cytochrome oxidase-1 (COX-1) and NADH dehydrogenase-1 (ND-1) mitochondrial DNA from 34, 14 and 3 flukes revealed 10, 4 and 1 unique haplotypes, respectively. Single nucleotide polymorphisms in these haplotypes were used to differentiate between D. chinensis and D. dendriticum, and confirm the molecular species identity of each of the lancet flukes as D. dendriticum. Phylogenetic comparison of the D. dendriticum rDNA, COX-1 and ND-1 sequences with those from D. chinensis, Fasciola hepatica and Fasciola gigantica species was performed to assess within and between species variation and validate the use of species-specific markers for D. dendriticum. Genetic variations between D. dendriticum populations derived from different locations in the Himalaya ranges of Pakistan illustrate the potential impact of animal movements on gene flow. This work provides a proof of concept for the validation of species-specific D. dendriticum markers and is the first molecular confirmation of this parasite species from the Himalaya ranges of Pakistan. The characterisation of this parasite will allow research questions to be addressed on its ecology, biological diversity, and epidemiology.

Three new species of Lachemilla (Rosaceae) from South America

Three new species of Lachemilla (Rosaceae), two from Colombia and one from Peru, are described and illustrated. Lachemillarothmaleriana is characterized by its stout stems, sericeous-villous indumentum, and wide ascending sheaths with trilobate lateral lobes. Lachemillaargentea presents a unique combination of tripartite basal leaves with an adaxial silvery villous indumentum, and decumbent branches with verticillate lobed sheaths. Finally, Lachemillacyanea has distinctly basal reniform leaves with a blue-green color and hirsute pubescence. Phylogenetic analyses of the nuclear ribosomal cistron and multiple regions of the plastid genome revealed the allopolyploid origin of the three new taxa.

Molecular and classical chromosomal techniques reveal diversity in bushcricket genera of Barbitistini (Orthoptera)

The cytogenetic characteristics of 17 species of bushcricket belonging to eight genera of the tribe Barbitistini were examined by fluorescence in situ hybridization with 18S rDNA and (TTAGGn) telomeric as probes and by C-banding, silver, and fluorochrome staining. These markers were used to understand chromosomal organization and evolutionary relationships between genera or species within the same genus. The number of 18S rDNA clusters per haploid genome that co-localized with active nucleolus organizer regions (NORs) ranged from one to five, with the most common pattern being the presence of one NOR-bearing chromosome. This ribosomal cistron was preferentially located in the paracentromeric region of autosomes and very rarely in the sex chromosome. The results demonstrated coincidence between the localization of major ribosomal genes and active NORs and the position of C-band and GC-rich regions. The rDNA/NOR distribution and the composition of chromosome heterochromatin proved to be good cytogenetic markers for distinguishing species and phylogenetic lines and for understanding the genomic differentiation and evolution of Barbitistini. A comparison of cytogenetic and morphological or behavioral traits suggests that morphological and behavioral specialization in this group was not followed by major karyotype modification (except for Leptophyes). However, the occurrence and distribution of different repetitive DNA sites tends to vary among the taxa.