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Six novel Bifidobacterium strains H1HS16N T , Bin2N, Hma3N, H6bp22N, H1HS10N, and H6bp9N, were isolated from the honey stomach of Apis mellifera. Cells are Gram-positive, non-motile, non-sporulating, facultatively anaerobic, and fructose 6-phosphate phosphoketolase-positive. Optimal growth conditions occur at 37 °C in anaerobiosis in MRS medium added with 2 % fructose and 0.1 % L-cysteine. The 16S rRNA gene sequences analysis revealed clustering with Bifidobacterium species found in honeybees. Strains Hma3N, H6bp22N, and H1HS16N T showed significant similarity to Bifidobacterium polysaccharolyticum JCM 34588 T , with an average similarity of 99.63 %. In contrast, strains Bin2N, H1HS10N, and H6bp9N were closely related to Bifidobacterium apousia JCM 34587 T , with an average similarity of 99.22 %. Moreover, strains Hma3N and H6bp22N exhibited ANI values of 96.65 % and 96.53 % when compared to Bifidobacterium polysaccharolyticum JCM 34588 T , while strains H1HS16N T , Bin2N, H6bp9N, and H1HS10N revealed ANI values of 94.18 %, 94.33 %, 94.22 %, and 95.50 % respectively when compared to B. apousia JCM 34587 T . dDDH analysis confirmed that strains Hma3N and H6bp22N belong to B. polysaccharolyticum, whereas strains H1HS16N T , Bin2N, H6bp9N, and H1HS10N represent a novel species. The peptidoglycan of the novel species is of the A4α type (L-Lys-D-Asp). The main cellular fatty acids of the type strain H1HS16N T are C 16:0 , C 14:0 , C 19:0 cyclo ω9c, and C 18:1 ω9c. The DNA G + C content of the type strain is 60.8 mol%. Genome analyses of the strains were also conducted to determine their biosynthesis-related gene clusters, probiotic features, and ecological distribution patterns. Phenotypic and genotypic characterization show that strain H1HS16N T is distinct from the type strains of other recognized Bifidobacterium species. Thus, Bifidobacterium kimbladii sp. nov. (H1HS16N T  = DSM 115187 T  = CCUG 76695 T ) is proposed as a novel Bifidobacterium species., Competing Interests: Declaration of competing interest A.V. and T.C.O. are the founders of and hold stocks in ConCellae AB, a university spin-off company that develops and markets products for humans and bees. A.V. and T.C.O. are inventors of three patent applications related to the applications of Lactobacillus and Bifidobacterium strains isolated from honeybees. However, the present study was not funded by ConCellae AB., (Copyright © 2025 Elsevier GmbH. All rights reserved.)

Geographic isolation and chromosome evolution are two of the major drivers of diversification in eukaryotes in general, and specifically, in plants. On one hand, range shifts induced by Pleistocene glacial oscillations deeply shaped the evolutionary trajectories of species in the Northern Hemisphere. On the other hand, karyotype variability within species or species complexes may have adaptive potential as different karyotypes may represent different recombination rates and linkage groups that may be associated with locally adapted genes or supergenes. Organisms with holocentric chromosomes are ideal to study the link between local adaptation and chromosome evolution, due to their high cytogenetic variability, especially when it seems to be related to environmental variation. Here, we integrate the study of the phylogeography, chromosomal evolution and ecological requirements of a plant species complex distributed in the Western Euro-Mediterranean region (Carex gr. laevigata, Cyperaceae). We aim to clarify the relative influence of these factors on population differentiation and ultimately on speciation. We obtained a well-resolved RADseq phylogeny that sheds light on the phylogeographic patterns of molecular and chromosome number variation, which are compatible with south-to-north postglacial migration. In addition, landscape genomics analyses identified candidate loci for local adaptation, and also strong significant associations between the karyotype and the environment. We conclude that karyotype distribution in C. gr. laevigata has been constrained by both range shift dynamics and local adaptation. Our study demonstrates that chromosome evolution may be responsible, at least partially, for microevolutionary patterns of population differentiation and adaptation in Carex., (© 2023 The Authors. Molecular Ecology published by John Wiley & Sons Ltd.)

Seven bifidobacterial strains were isolated from the faeces of two adult males of the two-toed sloth ( Choloepus didactylus ) housed in Parco Natura Viva, in Italy. Comparative sequence analysis of 16S rRNA and of five housekeeping ( hsp 60, rpo B, clp C, dna J, dna G) genes revealed that these strains were classified into two clusters. On the basis of 16S rRNA gene sequence similarity, the type strain of Bifidobacterium catenulatum subsp. kashiwanohense DSM 21854 T (95.4 %) was the closest neighbour to strain in Cluster I (BRDM 6 T ), whereas the type strain of Bifidobacterium dentium DSM 20436 T (values were in the range of 98‒99.8 %) was the closest neighbour to the other six strains in Cluster II. The average nucleotide identity (ANI) values of BRDM 6 T and of strains in Cluster II with the closely related type strains were 76.0 and 98.9 % (mean value) respectively. Therefore, genotyping based on the genome sequence of the strain BRDM 6 T combined with phenotypic analyses clearly revealed that the strain BRDM 6 T represents a novel species for which the names Bifidobacterium choloepi sp. nov. (BRDM 6 T =NBRC 114053 T =BCRC 81222 T ) is proposed.

Fifteen bifidobacterial strains were obtained from faeces of Rousettus aegyptiacus; after grouping them by RAPD PCR only eight were selected and characterized. Analysis of 16S rRNA and of five housekeeping (hsp60, rpoB, clpC, dnaJ, dna G) genes revealed that these eight strains were classified into five clusters: Cluster I (RST 8 and RST 16 T ), Cluster II (RST 9 T and RST 27), Cluster III (RST 7 and RST 11), Cluster IV (RST 19), Cluster V (RST 17) were closest to Bifidobacterium avesanii DSM 100685 T (96.3%), Bifidobacterium callitrichos DSM 23973 T (99.2% and 99.7%), Bifidobacterium tissieri DSM 100201 T (99.7 and 99.2%), Bifidobacterium reuteri DSM 23975 T (98.9%) and Bifidobacterium myosotis DSM 100196 T (99.3%), respectively. Strains in Cluster I and strain RST 9 in Cluster II could not be placed within any recognized species while the other ones were identified as known species. The average nucleotide identity values between two novel strains, RST 16 T and RST 9 T and their closest relatives were lower than 79% and 89%, respectively. In silico DNA-DNA hybridization values for those closest relatives were 32.5 and 42.1%, respectively. Phenotypic and genotypic tests demonstrated that strains in Cluster I and RST 9 T in Cluster II represent two novel species for which the names Bifidobacterium vespertilionis sp. nov. (RST 16 T =BCRC 81138 T =NBRC 113380 T =DSM 106025 T ; RST 8=BCRC 81135=NBRC 113377) and Bifidobacterium rousetti sp. nov. (RST 9 T =BCRC 81136 T =NBRC 113378 T =DSM 106027 T ) are proposed., (Copyright © 2019 Elsevier GmbH. All rights reserved.)

A novel irregularly shaped and slightly curved rod bacterial strain, GLDI4/2 T , showing activity of fructose 6-phosphate phosphoketolase was isolated from a faecal sample of an adult gelada baboon ( Theropithecus gelada ). Phylogenetic analyses based on 16S rRNA genes as well as multilocus sequences (representing fusA , gyrB and xfp genes) and the core genome revealed that GLDI4/2 T exhibited phylogenetic relatedness to Alloscardovia omnicolens DSM 21503 T and to Alloscardovia macacae DSM 24762 T . Comparative analysis of 16S rRNA gene sequences confirmed the phylogenetic results showing the highest gene sequence identity with strain A. omnicolens DSM 21503 T (96.0 %). Activities of α- and β-gluco(galacto)sidases were detected in strain GLDI4/2 T , which is characteristic for almost all members of the family Bifidobacteriaceae . Compared to other Alloscardovia species its DNA G+C content (43.8 mol%) was very low. Phylogenetic studies and the evaluation of phenotypic characteristics, including the results of biochemical, physiological and chemotaxonomic analyses, confirmed the novel species status for strain GLDI4/2 T , for which the name Alloscardoviatheropitheci sp. nov. is proposed. The type strain is GLDI4/2 T (=DSM 106019 T =JCM 32430 T ).

A novel Bifidobacterium strain, MRM 9.3 T , was isolated from a faecal sample of a baby common marmoset (Callithrixjacchus). Cells were Gram-stain-positive, non-motile, non-sporulating, non-haemolytic, facultatively anaerobic and fructose 6-phosphate phosphoketolase-positive. Phylogenetic analyses based on 16S rRNA genes as well as multilocus sequences (representing hsp60, rpoB, clpC, dnaJ and dnaG genes) and the core genomes revealed that strain MRM 9.3 T exhibited phylogenetic relatedness to Bifidobacterium myosotis DSM 100196 T . Comparative analysis of 16S rRNA gene sequences confirmed the phylogenetic results showing the highest gene sequence identity with strain B.ifidobacterium myosotis DSM 100196 T (95.6 %). The average nucleotide identity, amino acid average identity and in silico DNA-DNA hybridization values between MRM 9.3 T and DSM 100196 T were 79.9, 72.1 and 28.5 %, respectively. Phenotypic and genotypic features clearly showed that the strain MRM 9.3 T represents a novel species, for which the name Bifidobacterium jacchi sp. nov. is proposed. The type strain is MRM 9.3 T (=DSM 103362 T =JCM 31788 T ).

Large-scale changes in chromosome number have been associated with diversification rate shifts in many lineages of plants. For instance, several ancient rounds of polyploidization events have been inferred to promote genomic differentiation and/or isolation and, consequently, angiosperm diversification. Dysploidy, although less studied, has been suggested to also play an important role in angiosperm diversification. In this article, we aim to elucidate the role of chromosomal rearrangements on lineage diversification by analyzing a new comprehensive sedge (Cyperaceae) phylogenetic tree. Our null hypothesis is that the mode and tempo of chromosome evolution are to be homogeneous across the complete phylogeny. In order to discern patterns of diversification shifts and chromosome number changes within the family tree, we tested clade-specific chromosome evolution models for several subtrees according to previously reported increments of diversification rates. Results show that a complex, heterogeneous model composed of different clade-specific chromosome evolution transitions are significantly supported against the null hypothesis of a model with no chromosome number model transition events along the phylogeny. This could suggest a link between diversification and changes in chromosome number evolution although other possibilities are not discarded. Our methodological approach may allow identifying different patterns of chromosome evolution, as found for Cyperaceae, for other lineages at different evolutionary levels., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Four novel Gram-stain-positive, non spore forming and fructose-6-phosphate phosphoketolase-positive strains were isolated from the faeces of a cotton top tamarin (Saguinus oedipus) and an emperor tamarin (Saguinus imperator). Phylogenetic analyses based on 16S rRNA revealed that bifidobacterial strains TRE 1 T exhibit close phylogenetic relatedness to Bifidobacterium catulorum DSM 103154 (96.0%) and Bifidobacterium tissieri DSM 100201 (96.0%); TRE D T and TRE H T were closely related to Bifidobacterium longum subsp. longum ATCC 15708 T with similarity values of 97.4% and 97.5%, respectively; TRI 7 T was closely related to Bifidobacterium tissieri DSM 100201 (96.0%). The Average Nucleotide Identity (ANI) and in silico DDH (isDDH) analysis with closest neighbour supported an independent phylogenetic position of all strains with values ranged from 74 to 85% for ANI and from 24 to 28% for isDDH. DNA base composition of the four strains was in the range of 58.3-63.5mol% G+C. Based on the phylogenetic, genotypic and phenotypic data, the strains TRE 1 T , TRE D T , TRE H T and TRI 7 T clearly represent four novel taxa within the genus Bifidobacterium for which the names Bifidobacterium primatium sp. nov. (type strain TRE 1 T =DSM 100687 T =JCM 30945 T ), Bifidobacterium scaligerum sp. nov. (type strain TRE D T =DSM 103140 T =JCM 31792 T ), Bifidobacterium felsineum sp. nov. (type strain TRE H T =DSM 103139 T =JCM 31789 T ) and Bifidobacterium simiarum sp. nov. (type strain TRI 7 T =DSM 103153 T =JCM 31793) are proposed., (Copyright © 2018 Elsevier GmbH. All rights reserved.)

In our previous study based on hsp60 PCR-restriction fragment length polymorphism and 16S rRNA gene sequencing, we stated that the bifidobacterial strains isolated from the individual faecal samples of five baby common marmosets constituted different phylogenetically isolated groups of the genus Bifidobacterium. In that study, we also proposed that these isolated groups potentially represented novel species of the genus Bifidobacterium. Out of them, Bifidobacterium aesculapii, Bifidobacterium myosotis, Bifidobacterium tissieri and Bifidobacterium hapali, have been described recently. Another strain, designated MRM 8.19 T , has been classified as member of the genus Bifidobacterium on the basis of positive results for fructose-6-phosphate phosphoketolase activity and analysis of partial 16S rRNA, hsp60, clpC, dnaJ, dnaG and rpoB gene sequences. Analysis of 16S rRNA and hsp60 gene sequences revealed that strain MRM 8.19 T was related to B. tissieri DSM 100201 T (95.8 %) and to Bifidobacterium bifidum ATCC 29521 T (93.7 %), respectively. The DNA G+C composition was 63.7 mol% and the peptidoglycan structure was l-Orn(Lys)-l-Ser. Based on the phylogenetic, genotypic and phenotypic data reported, strain MRM 8.19 T represents a novel taxon within the genus Bifidobacterium for which the name Bifidobacterium catulorum sp. nov. (type strain MRM 8.19 T =DSM 103154 T =JCM 31794 T ) is proposed.

Three Gram-stain-positive, non-spore-forming, microaerophilic and fructose-6-phosphate phosphoketolase positive strains were isolated from a faecal sample of an adult subject of the emperor tamarin (Saguinus imperator). Given that the isolates revealed identical BOX PCR profiles, strain TRI 5 T was selected as a representative and characterized further. Comparative analysis of 16S rRNA gene sequence similarity revealed that strain TRI 5 T was closely related to Bifidobacterium saguini DSM 23967 T (96.4 %) and to Bifidobacterium longum subsp. longum ATCC 15708 (96.2 %). Multilocus sequence analyses of five housekeeping genes showed the close phylogenetic relatedness of this strain to Bifidobacterium breve DSM 20213 T (hsp60 94.1 %), Bifidobacterium saguini DSM 23967 T (clpC 91 %), Bifidobacterium avesanii DSM 100685 T (dnaG 80.3 %), Bifidobacterium longumsubsp. infantis ATCC 15697 T (dnaJ 85.3 %) and Bifidobacterium longumsubsp. longum ATCC 15708 (rpoB 93 %), respectively. The peptidoglycan type was A3β, with an interpeptide bridge comprising l-Orn (Lys) - l-Ser - l-Ala - l-Thr - l-Ala. The DNA G+C content of strain TRI 5 T was 60.9 mol%. Based on the data provided, strain TRI 5 T represents a novel species of the genus Bifidobacterium for which the name Bifidobacteriumcallitrichidarum sp. nov. is proposed. The type strain is TRI 5 T (=DSM 103152 T =JCM 31790 T ).

Background: Members of the Bifidobacteriaceae family represent both dominant microbial groups that colonize the gut of various animals, especially during the suckling stage of their life, while they also occur as pathogenic bacteria of the urogenital tract. The pan-genome of the genus Bifidobacterium has been explored in detail in recent years, though genomics of the Bifidobacteriaceae family has not yet received much attention. Here, a comparative genomic analyses of 67 Bifidobacteriaceae (sub) species including all currently recognized genera of this family, i.e., Aeriscardovia, Alloscardovia, Bifidobacterium, Bombiscardovia, Gardnerella, Neoscardovia, Parascardovia, Pseudoscardovia and Scardovia, was performed. Furthermore, in order to include a representative of each of the 67 (currently recognized) (sub) species belonging to the Bifidobacteriaceae family, we sequenced the genomes of an additional 11 species from this family, accomplishing the most extensive comparative genomic analysis performed within this family so far., Results: Phylogenomics-based analyses revealed the deduced evolutionary pathway followed by each member of the Bifidobacteriaceae family, highlighting Aeriscardovia aeriphila LMG 21773 as the deepest branch in the evolutionary tree of this family. Furthermore, functional analyses based on genome content unveil connections between a given member of the family, its carbohydrate utilization abilities and its corresponding host. In this context, bifidobacterial (sub) species isolated from humans and monkeys possess the highest relative number of acquired glycosyl hydrolase-encoding genes, probably in order to enhance their metabolic ability to utilize different carbon sources consumed by the host., Conclusions: Within the Bifidobacteriaceae family, genomics of the genus Bifidobacterium has been extensively investigated. In contrast, very little is known about the genomics of members of the other eight genera of this family. In this study, we decoded the genome sequences of each member of the Bifidobacteriaceae family. Thanks to subsequent comparative genomic and phylogenetic analyses, the deduced pan-genome of this family, as well as the predicted evolutionary development of each taxon belonging to this family was assessed.

Premise of the Study: The sedge Carex macloviana d'Urv presents a bipolar distribution. To clarify the origin of its distribution, we consider the four main hypotheses: long-distance dispersal (either by mountain hopping or by direct dispersal), vicariance, parallel evolution, and human introduction., Methods: Phylogenetic, phylogeographic, and divergence time estimation analyses were carried out based on two nuclear ribosomal (ETS and ITS) regions, one nuclear single copy gene (CATP), and three plastid DNA regions ( rps 16 and 5' trn K introns, and psb A -trn H spacer), using Bayesian inference, maximum likelihood, and statistical parsimony. Bioclimatic data were used to characterize the climatic niche of C . macloviana ., Key Results: Carex macloviana constitutes a paraphyletic species, dating back to the Pleistocene (0.62 Mya, 95% highest posterior density: 0.29-1.00 Mya). This species displays strong genetic structure between hemispheres, with two different lineages in the Southern Hemisphere and limited genetic differentiation in Northern Hemisphere populations. Also, populations from the Southern Hemisphere show a narrower climatic niche with regards to the Northern Hemisphere populations., Conclusions: Carex macloviana reached its bipolar distribution by long-distance dispersal, although it was not possible to determine whether it was caused by mountain hopping or by direct dispersal. While there is some support that Carex macloviana might have colonized the Northern Hemisphere by south-to-north transhemisphere dispersal during the Pleistocene, unlike the southwards dispersal pattern inferred for other bipolar Carex L. species, we cannot entirely rule out north-to-south dispersion., (© 2017 Botanical Society of America.)

In a previous study on bifidobacterial distribution in New World monkeys, six strains belonging to the Bifidobacteriaceae were isolated from faecal samples of baby common marmosets (Callithrix jacchus L.). All the isolates were Gram-positive-staining, anaerobic, asporogenous and fructose-6-phosphate phosphoketolase-positive. Comparative analysis of 16S rRNA gene sequences revealed relatively low levels of similarity (maximum identity 96 %) to members of the genus Bifidobacterium, and placed the isolates in three independent clusters: strains of cluster I (MRM_5.9T and MRM_5.10) and cluster III (MRM_5.18T and MRM_9.02) respectively showed 96.4 and 96.7 % 16S rRNA gene sequence similarity to Bifidobacterium callitrichos DSM 23973T, while strains of cluster II (MRM_8.14T and MRM_9.14) showed 95.4 % similarity to Bifidobacterium stellenboschense DSM 23968T. Phylogenetic analysis of partial hsp60 and clpC gene sequences supported an independent phylogenetic position of each cluster from each other and from the related type strains B. callitrichos DSM 23973T and B. stellenboschense DSM 23968T. Clusters I, II and III respectively showed DNA G+C contents of 64.9-65.1, 56.4-56.7 and 63.1-63.7 mol%. The major cellular fatty acids of MRM_5.9T were C14 : 0, C16 : 0 and C18 : 1ω9c dimethylacetal, while C16 : 0 was prominent in strains MRM_5.18T and MRM_8.14T, followed by C18 : 1ω9c and C14 : 0. Biochemical profiles and growth parameters were recorded for all the isolates. Based on the data provided, the clusters represent three novel species, for which the names Bifidobacterium myosotis sp. nov. (type strain MRM_5.9T = DSM 100196T = JCM 30796T), Bifidobacterium hapali sp. nov. (type strain MRM_8.14T = DSM 100202T = JCM 30799T) and Bifidobacterium tissieri sp. nov. (type strain MRM_5.18T = DSM 100201T = JCM 30798T) are proposed.

Four Gram-positive-staining, microaerophilic, non-spore-forming, fructose-6-phosphate phosphoketolase-positive bacterial strains were isolated from a faecal sample of a 5-year-old ring-tailed lemur (Lemur catta). The strains showed a peculiar morphology, resembling a small coiled snake, a ring shape, or forming a little 'Y' shape. The isolated strains appeared identical, and LMC 13T was chosen as a representative strain and characterized further. Strain LMC 13T showed an A3β peptidoglycan type, similar to that found in Bifidobacterium longum. The DNA base composition was 57.2 mol% G+C. Almost-complete 16S rRNA, hsp60, rpoB, dnaJ, dnaG, purF, clpC and rpoC gene sequences were obtained, and phylogenetic relationships were determined. Comparative analysis of 16S rRNA gene sequences showed that strain LMC 13T showed the highest similarity to B. longum subsp. suis ATCC 27533T (96.65 %) and Bifidobacterium saguini DSM 23967T (96.64 %). Strain LMC 13T was located in an actinobacterial cluster and was more closely related to the genus Bifidobacteriumthan to other genera in the Bifidobacteriaceae. On the basis of these results, strain LMC 13T represents a novel species within the genus Bifidobacterium, for which the name Bifidobacterium lemurum sp. nov. is proposed; the type strain is LMC 13T ( = DSM 28807T = JCM 30168T).

Six Gram-positive-staining, microaerophilic, non-spore-forming, fructose-6-phosphate phosphoketolase-positive bacterial strains with a peculiar morphology were isolated from faecal samples of baby common marmosets (Callithrix jacchus). Cells of these strains showed a morphology not reported previously for a bifidobacterial species, which resembled a coiled snake, always coiled or ring shaped or forming a 'Y' shape. Strains MRM 3/1(T) and MRM 4/2 were chosen as representative strains and characterized further. The bacteria utilized a wide range of carbohydrates and produced urease. Glucose was fermented to acetate and lactate. Strain MRM 3/1(T) showed a peptidoglycan type unique among members of the genus Bifidobacterium. The DNA base composition was 64.7 mol% G+C. Almost-complete 16S rRNA, hsp60, clpC and rpoB gene sequences were obtained and phylogenetic relationships were determined. Comparative analysis of 16S rRNA gene sequences showed that strains MRM 3/1(T) and MRM 4/2 had the highest similarities to Bifidobacterium scardovii DSM 13734(T) (94.6%) and Bifidobacterium stellenboschense DSM 23968(T) (94.5%). Analysis of hsp60 showed that both strains were closely related to B. stellenboschense DSM 23968(T) (97.5% similarity); however, despite this high degree of similarity, our isolates could be distinguished from B. stellenboschense DSM 23968(T) by low levels of DNA-DNA relatedness (30.4% with MRM 3/1(T)). Strains MRM 3/1(T) and MRM 4/2 were located in an actinobacterial cluster and were more closely related to the genus Bifidobacterium than to other genera in the family Bifidobacteriaceae. On the basis of these results, strains MRM 3/1(T) and MRM 4/2 represent a novel species within the genus Bifidobacterium, for which the name Bifidobacterium aesculapii sp. nov. is proposed; the type strain is MRM 3/1(T) ( = DSM 26737(T) = JCM 18761(T))., (© 2014 IUMS.)

Background: Bifidobacterium represents one of the largest genus within the Actinobacteria, and includes at present 32 species. These species share a high sequence homology of 16S rDNA and several molecular techniques already applied to discriminate among them give ambiguous results., Results: This work illustrates a simple and cheap molecular tool for the identification of Bifidobacterium species. The hsp60 universal primers were used in a simple PCR procedure for the direct amplification of 590 bp of the hsp60 sequence. The in silico restriction analysis of bifidobacterial hsp60 partial sequences allowed the identification of a single endonuclease (HaeIII) able to provide different PCR-restriction fragment length polymorphism (RFLP) patterns in the Bifidobacterium spp. type strains evaluated. The electrophoretic analyses allowed to confirm the different RFLP patterns., Conclusions: The developed PCR-RFLP technique resulted in efficient discrimination of the tested species and subspecies and allowed the construction of a dichotomous key in order to differentiate the most widely distributed Bifidobacterium species as well as the subspecies belonging to B. pseudolongum and B. animalis.

Premise of the Study: The Ibero-North African Carex sect. Phacocystis river-shore group is a set of perennial helophytic species with poorly defined taxonomic boundaries. In the present study, we delimited the different taxonomic units, addressed the phylogeographic history, and evaluated the drivers of differentiation that have promoted diversification of these plants., Methods: We analyzed molecular data using statistical parsimony for plastid sequences (26 samples from 26 populations) and principal coordinate analysis, neighbor joining, and Bayesian analysis of population structure for AFLPs (186 samples from 26 populations). Chromosome numbers from 14 samples (9 populations) are newly reported., Key Results: Three species can be distinguished (C. acuta, C. elata, and C. reuteriana). Unexpectedly for rhizome-growing helophytes, the vegetative reproduction detected was incidental. The widespread C. elata was found to be a genetically poorly differentiated taxon, whereas the local C. reuteriana displayed geographical structuring. Geographical factors seem to be the main driver of differentiation for both taxa., Conclusions: Despite apparent morphological and ecological similarities, C. elata and C. reuteriana have disparate genetic structures and evolutionary histories, which may have originated from small ecological differences. Carex elata is broadly distributed throughout Europe, and its northern populations were recently founded, probably after the last glacial maximum. In contrast, C. reuteriana is an Ibero-North African endemic, with long-standing populations affected by isolation and limited gene flow. It is likely that high-density blocking effects and different gene-flow barriers act together to delimit its distribution and promote its relatively high population differentiation.

Previous work on holocentric chromosomes in the angiosperm genus Carex demonstrates that many of the traditional sections are marked by different ranges of chromosome number, suggesting phylogenetic autocorrelation. It has been hypothesized that shifting constraints on chromosome rearrangements may limit the potential for hybridization among lineages, promoting speciation. In this study, we evaluated alternative evolutionary models to test for such transitions in Carex section Spirostachyae as well as the relative effects of several plausible drivers of intraspecific chromosome diversity. Chromosome number variation in section Spirostachyae shows significant phylogenetic signal, but no evidence of clade-specific shifts in chromosome number distribution. This gradual model of chromosome evolution contrasts with the shifting equilibrium model previously identified in a younger section of the same genus, suggesting that section Spirostachyae may have a more slowly evolving karyotype. Chromosome number variance, on the other hand, exhibits low phylogenetic signal. Average time of coalescence rather than geographic range or chromosome number itself predicts chromosome number variance, demonstrating a previously unreported relationship between population history and cytogenetic variation., (Copyright 2010 Elsevier Inc. All rights reserved.)

Incongruence between gene trees, even within genomes, is often the result of hybridization and/or other processes such as incomplete lineage sorting, and can cause problems for phylogenetic analyses. We show here that the radiation of the Cyperaceae genus Schoenoxiphium involved at least one hybridization event with a closely related species of Carex, as indicated by a recombinant nuclear ITS region shared by all species in the S. rufum clade and C. camptoglochin. Recombinant sequences were confirmed with cloning experiments and recombination analyses. The monophyly of Schoenoxiphium has, in previous analyses, been suspected but not sufficiently supported, possibly due in part to this problem. Our phylogenetic analyses include an appropriate representation of Schoenoxiphium and other related Cariceae species and an extended sampling of the nuclear ITS and plastid marker regions, trnLF and rps16. We demonstrate that Schoenoxiphium is monophyletic, nested within Carex, and that several supported clades exist in Schoenoxiphium., (Copyright 2010 Elsevier Inc. All rights reserved.)