Search

Background and Aims: Southwestern Asia is a significant centre of biodiversity and a cradle of diversification for many plant groups, especially xerophytic elements. In contrast, little is known about the evolution and diversification of its hygrophytic flora. To fill this gap, we focus on Cardamine (Brassicaceae) species that grow in wetlands over a wide altitudinal range. We aimed to elucidate their evolution, assess the extent of presumed historical gene flow between species, and draw inferences about intraspecific structure., Methods: We applied the phylogenomic Hyb-Seq approach, ecological niche analyses and multivariate morphometrics to a total of 85 Cardamine populations from the target region of Anatolia-Caucasus, usually treated as four to six species, and supplemented them with close relatives from Europe., Key Results: Five diploids are recognized in the focus area, three of which occur in regions adjacent to the Black and/or Caspian Sea (C. penzesii, C. tenera, C. lazica), one species widely distributed from the Caucasus to Lebanon and Iran (C. uliginosa), and one western Anatolian entity (provisionally C. cf. uliginosa). Phylogenomic data suggest recent speciation during the Pleistocene, likely driven by both geographic separation (allopatry) and ecological divergence. With the exception of a single hybrid (allotetraploid) speciation event proven for C. wiedemanniana, an endemic of southern Turkey, no significant traces of past or present interspecific gene flow were observed. Genetic variation within the studied species is spatially structured, suggesting reduced gene flow due to geographic and ecological barriers, but also glacial survival in different refugia., Conclusions: This study highlights the importance of the refugial regions of the Black and Caspian Seas for both harbouring and generating hygrophytic species diversity in Southwestern Asia. It also supports the significance of evolutionary links between Anatolia and the Balkan Peninsula. Reticulation and polyploidization played a minor evolutionary role here in contrast to the European relatives., (© The Author(s) 2023. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Background and Aims: Cardamine occulta (Brassicaceae) is an octoploid weedy species (2n = 8x = 64) originated in Eastern Asia. It has been introduced to other continents including Europe and considered to be an invasive species. Despite its wide distribution, the polyploid origin of C. occulta remained unexplored. The feasibility of comparative chromosome painting (CCP) in crucifers allowed us to elucidate the origin and genome evolution in Cardamine species. We aimed to investigate the genome structure of C. occulta in comparison with its tetraploid (2n = 4x = 32, C. kokaiensis and C. scutata) and octoploid (2n = 8x = 64, C. dentipetala) relatives., Methods: Genomic in situ hybridization (GISH) and large-scale CCP were applied to uncover the parental genomes and chromosome composition of the investigated Cardamine species., Key Results: All investigated species descended from a common ancestral Cardamine genome (n = 8), structurally resembling the Ancestral Crucifer Karyotype (n = 8), but differentiated by a translocation between chromosomes AK6 and AK8. Allotetraploid C. scutata originated by hybridization between two diploid species, C. parviflora and C. amara (2n = 2x = 16). By contrast, C. kokaiensis has an autotetraploid origin from a parental genome related to C. parviflora. Interestingly, octoploid C. occulta probably originated through hybridization between the tetraploids C. scutata and C. kokaiensis. The octoploid genome of C. dentipetala probably originated from C. scutata via autopolyploidization. Except for five species-specific centromere repositionings and one pericentric inversion post-dating the polyploidization events, the parental subgenomes remained stable in the tetra- and octoploids., Conclusions: Comparative genome structure, origin and evolutionary history was reconstructed in C. occulta and related species. For the first time, whole-genome cytogenomic maps were established for octoploid plants. Post-polyploid evolution in Asian Cardamine polyploids has not been associated with descending dysploidy and intergenomic rearrangements. The combination of different parental (sub)genomes adapted to distinct habitats provides an evolutionary advantage to newly formed polyploids by occupying new ecological niches., (© The Author(s) 2019. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Unlabelled: •, Premise of the Study: Contact zones between diploids and their autopolyploid descendants represent a unique evolutionary venue for studying polyploid establishment, cytotype coexistence, and interactions. Here, we examine cytotype coexistence in a diploid-tetraploid contact zone of a perennial herb, Cardamine amara, located north of the Alps by assessing cytotype spatial patterns, ecological divergence, and genetic variation and structure.•, Methods: Flow cytometry was applied to screen DNA ploidy levels in 302 populations (3296 individuals) and the genetic variation of a selection of 25 populations was examined using microsatellite and AFLP markers. Environmental (landscape and climatic) data were analyzed to assess ecological differentiation between the cytotypes.•, Key Results: A parapatric distribution of the cytotypes with a relatively wide (over 100 km in some regions) secondary contact zone was identified. Mixed-ploidy populations, documented for the first time in this species, as well as triploid individuals were found along the diploid-tetraploid borderline. Different climatic requirements of the two main cytotypes were revealed, mirrored in their altitudinal separation. The tetraploids were genetically differentiated from both the diploids and the modeled, in silico autotetraploid genotypes, in accordance with the assumed polyploid origin and spread linked to past glaciations, and largely independent evolution in allopatry.•, Conclusions: The observed spatial and genetic patterns likely reflect the evolutionary and colonization history of the two cytotypes and have been maintained by multiple factors such as ecological divergence, limited gene flow between the cytotypes, and the restricted dispersal capacity., (© 2015 Botanical Society of America, Inc.)

The origin of Cardamine flexuosa (Wavy Bittercress) has been a conundrum for more than six decades. Here we identify its parental species, analyse its genome structure in comparison to parental genomes and describe intergenomic structural variations in C. flexuosa. Genomic in situ hybridization (GISH) and comparative chromosome painting (CCP) uncovered the parental genomes and the chromosome composition of C. flexuosa and its presumed diploid progenitors. Cardamine flexuosa is an allotetraploid (2n = 4x = 32), originating from two diploid species, Cardamine amara and Cardamine hirsuta (2n = 2x = 16). The two parental species display almost perfectly conserved chromosomal collinearity for seven out of the eight chromosomes. A 13 Mb pericentric inversion distinguishes chromosome CA1 from CH1. A comparative cytomolecular map was established for C. flexuosa by CCP/GISH. Whereas conserved chromosome collinearity between the C. amara and C. hirsuta subgenomes might have promoted intergenomic rearrangements through homeologous recombination, only one reciprocal translocation between two homeologues has occurred since the origin of C. flexuosa. The genome of C. flexuosa demonstrates that allopolyploids can maintain remarkably stable subgenomes over 10(4) -10(5)  yr throughout a wide distribution range. By contrast, the rRNA genes underwent genome-specific elimination towards a diploid-like number of loci., (© 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.)

This article describes the use of cytogenomic and molecular approaches to explore the origin and evolution of Cardamine schulzii, a textbook example of a recent allopolyploid, in its ~110-year history of human-induced hybridization and allopolyploidy in the Swiss Alps. Triploids are typically viewed as bridges between diploids and tetraploids but rarely as parental genomes of high-level hybrids and polyploids. The genome of the triploid semifertile hybrid Cardamine × insueta (2n = 24, RRA) was shown to combine the parental genomes of two diploid (2n = 2x = 16) species, Cardamine amara (AA) and Cardamine rivularis (RR). These parental genomes have remained structurally stable within the triploid genome over the >100 years since its origin. Furthermore, we provide compelling evidence that the alleged recent polyploid C. schulzii is not an autohexaploid derivative of C. × insueta. Instead, at least two hybridization events involving C. × insueta and the hypotetraploid Cardamine pratensis (PPPP, 2n = 4x-2 = 30) have resulted in the origin of the trigenomic hypopentaploid (2n = 5x-2 = 38, PPRRA) and hypohexaploid (2n = 6x-2 = 46, PPPPRA). These data show that the semifertile triploid hybrid can promote a merger of three different genomes and demonstrate how important it is to reexamine the routinely repeated textbook examples using modern techniques.

Background and Aims: Intraspecific ploidy-level variation is an important aspect of a species' genetic make-up, which may lend insight into its evolutionary history and future potential. The present study explores this phenomenon in a group of eastern Asian Cardamine species., Methods: Plant material was sampled from 59 localities in Japan and Korea, which were used in karyological (chromosome counting) and flow cytometric analyses. The absolute nuclear DNA content (in pg) was measured using propidium iodide and the relative nuclear DNA content (in arbitrary units) was measured using 4,6-diamidino-2-phenylindole fluorochrome., Key Results: Substantial cytotype diversity was found, with strikingly different distribution patterns between the species. Two cytotypes were found in C. torrentis sensu lato (4x and 8x, in C. valida and C. torrentis sensu stricto, respectively), which displays a north-south geographical pattern in Japan. Hypotheses regarding their origin and colonization history in the Japanese archipelago are discussed. In Korean C. amaraeiformis, only tetraploids were found, and these populations may in fact belong to C. valida. C. yezoensis was found to harbour as many as six cytotypes in Japan, ranging from hexa- to dodecaploids. Ploidy levels do not show any obvious geographical pattern; populations with mixed ploidy levels, containing two to four cytotypes, are frequently observed throughout the range. C. schinziana, an endemic of Hokkaido, has hexa- and octoploid populations. Previous chromosome records are also revised, showing that they are largely based on misidentified material or misinterpreted names., Conclusions: Sampling of multiple populations and utilization of the efficient flow cytometric approach allowed the detection of large-scale variation in ploidy levels and genome size variation attributable to aneuploidy. These data will be essential in further phylogenetic and evolutionary studies.

The name Cardamine fallax (O. E. Schulz) Nakai, based on Cardamine flexuosa subsp. fallax O. E. Schulz, is lectotypified by the specimen originating from Japan (Mama-mura, Shimosa) in accordance with the original description and with the current use of the name by the majority of Japanese and Korean authors. Contrary to the treatment in the recent editions of the Flora of China and Flora of Japan, hexaploid C. fallax is considered here as a taxon different from diploid C. parviflora L. The main morphological difference between these two species is in the shape of cauline leaves. Those of C. parviflora are pinnatisect (lower ones seldom pinnate), with oblanceolate to linear, entire or almost entire segments or leaflets, and those of C. fallax are pinnate, usually with petiolulate, lobate, pinnatipartite to pinnatisect leaflets. The distribution area of C. fallax includes Japan, Korea and Eastern China.

The nomenclature of Eastern Asian populations traditionally assigned to Cardamine flexuosa has remained unresolved since 2006, when they were found to be distinct from the European species C. flexuosa. Apart from the informal designation "Asian C. flexuosa", this taxon has also been reported under the names C. flexuosa subsp. debilis or C. hamiltonii. Here we determine its correct species name to be C. occulta and present a nomenclatural survey of all relevant species names. A lectotype and epitype for C. occulta and a neotype for the illegitimate name C. debilis (replaced by C. flexuosa subsp. debilis and C. hamiltonii) are designated here. Cardamine occulta is a polyploid weed that most likely originated in Eastern Asia, but it has also been introduced to other continents, including Europe. Here data is presented on the first records of this invasive species in European countries. The first known record for Europe was made in Spain in 1993, and since then its occurrence has been reported from a number of European countries and regions as growing in irrigated anthropogenic habitats, such as paddy fields or flower beds, and exceptionally also in natural communities such as lake shores. [ABSTRACT FROM AUTHOR]

• Premise of the study: Studies on genetic structure of plant populations help us understand the history of local flora and vegetation. In this study, we focus on the temperate-boreal herb Cardamine scutata from northeast Asia, an area with scarce phylogeographic studies. We explore patterns of genetic variation within this species, with an aim to infer its (post-) glacial history with reference to colonization routes and migrations via land bridges. • Methods: We analyzed 46 populations sampled in Japan, Kamchatka, and Korea using AFLP and cpDNA sequence data. • Key results: Two intraspecific genetic groups were resolved, distributed in the northeastern and southwestern part of the study area, most likely reflecting lineages isolated from each other during (at least) the last glaciation. A zone of secondary contacts was found in central/northern Honshu, and it few cases of long-distance dispersal were observed. We detected efficient gone flow across the marine straits, supporting the role of land bridges created by sea level decline during the last glacial period. The cpDNA data indicated extensive recent expansion and diversification within both lineages. We inferred recent colonization of Kamchatka flora Hokkaido, associated with genetic impoverishment. • Conclusions: The pattern of north-south genetic differentiation found in C. scutata is rather common among several other plant species studied in Japan, despite their distinct biological features. We assume that different processes and factors may have brought about this similarity. Overall, this study contributes to better understanding of the biogeography of northeast Asia. [ABSTRACT FROM AUTHOR]

The western Balkans, characterized by high rates ofendemism, are recognized as one of the most diverse and speciesrich areas of Europe. The present study focuses on diploid speciation in a poorly explored ancestral group of the genus Cardan,ine that is distributed in the amphi-Adriatic territory. Morphological data and DNA sequences (plastid trnL intron and trnL-trnF spacer, ITS ofnrDNA, and single-copy nuclear gene CHS) were used to address taxonomic, phylogenetic and evolutionary questions. Recognition of several previously described, but recently not accepted narrow endemics is supported (C.fia/ae, C. rupestris, C. serbica). Cardamine maritima s.str. is segregated into three distinct entities, which were given species rank. A new taxonomic concept of the group is proposed, including identification key, synonymy, typifications, C. nionlenegrina sp. nov. and C. adriatica nom. nov. Chloroplast data indicate radiation of the ancestral lineage into a series ofdistinct endemic species; lack of resolution at internal nodes and incongruence with nuclear phylogenies suggest that this radiation occurred rapidly. Nuclear data indicate more recent hybridization events. It is assumed that glacial-induced local-scale and altitudinal migrations along the Balkan coastline and in adjacent massifs caused contacts between previously isolated populations, resulting in occasional interspecific gene-flow. Trans-Adriatic contacts and gene exchange are also suggested. [ABSTRACT FROM AUTHOR]

Aim We use Cardamine alpina and C. resedifolia as models to address the detailed history of disjunctions in the European alpine system. These species grow on siliceous bedrock: C. alpina in the Alps and Pyrenees, and C. resedifolia in several mountain ranges from the Sierra Nevada to the Balkans. We explore differentiation among their disjunct populations as well as within the contiguous Alpine and Pyrenean ranges, and compare the phylogeographical histories of these diploid sister species. We also include samples of the closely related, arctic diploid C. bellidifolia in order to explore its origin and post-glacial establishment. Location European alpine system, Norway and Iceland. Methods We employed amplified fragment length polymorphisms (AFLPs). AFLP data were analysed using principal coordinates analysis, neighbour joining and Bayesian clustering, and measures of diversity and differentiation were computed. Results For the snow-bed species C. alpina (27 populations, 203 plants) we resolved two strongly divergent lineages, corresponding to the Alps and the Pyrenees. Although multiple glacial refugia were invoked in the Pyrenees, we inferred only a single one in the Maritime Alps – from which rapid post-glacial colonization of the entire Alps occurred, accompanied by a strong founder effect. For C. resedifolia (33 populations, 247 plants), which has a broader ecological amplitude and a wider distribution, the genetic structuring was rather weak and did not correspond to the main geographical disjunctions. This species consists of two widespread and largely sympatric main genetic groups (one of them subdivided into four geographically more restricted groups), and frequent secondary contacts exist between them. Main conclusions The conspicuously different histories of these two sister species are likely to be associated with their different ecologies. The more abundant habitats available for C. resedifolia may have increased the probability of its gradual migration during colder periods and also of successful establishment after long-distance dispersal, whereas C. alpina has been restricted by its dependence on snow-beds. Surprisingly, the arctic C. bellidifolia formed a very divergent lineage with little variation, contradicting a scenario of recent, post-glacial migration from the Alps or Pyrenees. [ABSTRACT FROM AUTHOR]

The amphi-Adriatic region, and especially the Western Balkan Peninsula, belongs to the most important biodiversity hotspots in the temperate region. Nevertheless, detailed phylogeographic and molecular systematic studies in the Western Balkan are rare due to sporadic sampling in regions, where access has been, until recently, restricted by war. The Cardamine maritima group, which is the focus of this study, comprises not only the currently recognised species C. maritima and C. monteluccii, but also other taxa, which have been rendered to synonymy by most of the national floras and checklists. Molecular data acquired by the amplified fragment length polymorphism method showed a clear pattern within the group. Italian populations of C. monteluccii are well separated from Balkan taxa. In a step forward from previous taxonomic confusion surrounding Balkan populations, the present study confirms that five allopatric units—each with a clearly delimited and a rather restricted distribution range—can be easily recognised here. They correspond to C. fialae, C. serbica, C. rupestris, and two genetically distant and allopatric units within C. maritima. While individual taxa gained high bootstrap support in the neighbour-joining tree, there is low support for the internal nodes and it is hard to infer any relationships among taxa based on this information. The majority of Balkan populations of the C. maritima group exhibit features of genetic variability that enable us to hypothesise that these populations are relic ones. [ABSTRACT FROM AUTHOR]

The taxonomic position of Cardamine pectinata, a controversial taxon treated either as infraspecific to C. impatiens or as a separate species, was studied. Forty-nine populations were sampled and used in multivariate morphometric and molecular (amplified fragment length polymorphism) analyses. Our results showed that C. impatiens and C. pectinata represent two well-differentiated taxa in terms of both molecular and morphological data, and should be treated as two separate species. We present the taxonomic conspectus for both species, including the list of synonyms, information on type specimens, morphological descriptions, ecological characteristics, and distribution area. Type specimens for several names are designated here. The detailed geographical distribution of C. pectinata is presented based on the survey and revision of herbarium material. It covers the area from the Balkans through Turkey and the Caucasus to Iran. As an introduction to the phylogeography of both species, the distribution of genetic diversity within and between the studied populations and geographical regions was assessed. In C. pectinata, the highest genetic diversity was observed in northern Turkey, suggesting the location of glacial refugia along the Black Sea coast. Populations in Bulgaria were less diverse, and this area has most probably been colonized postglacially. C. impatiens, on the other hand, did not display clear phylogeographical structure, most probably as a result of the efficient spread and mixing between different colonization routes. [ABSTRACT FROM AUTHOR]

EndemicCardamine silanafrom Calabria (southern Italy) previously reported to be related toC. raphanifoliawas found to be hexaploid. Morphological characters and AFLP data were analysed to evaluate the degree of differentiation ofC. silanafrom closely related taxa and to find parental taxa of this polyploid.Cardamine apenninafrom theC. pratensisgroup was examined as one putative parent, as indicated in previous studies of nuclear ITS sequences, along with other related taxa based on both cpDNA and ITS sequences. Both multivariate morphometric analyses of quantitative characters and evaluation of qualitative morphological characters showed: (1) closest position ofC. silanato two diploids:C. acrisfrom the Balkan Peninsula andC. apenninafrom Central Italy; (2) good extent of morphological separation ofC. silanafrom related taxa; and (3) withinC. acrissubspecies,C. acrisssp.vardousiaefrom Central Greece as closest toC. silana. Neighbour-joining tree and PCoA ordinations of AFLP data, as well as patterns of AFLP bands sharing, corroborated results of multivariate morphometrics. This evidence supports an allopolyploid origin ofC. silana, withC. apenninaandC. acrisas parental taxa. Its origin may be dated to Pleistocene glacial events, because of the presumably wider geographical distributions of its parental taxa during more humid periods at that time. © 2005 The Linnean Society of London,Botanical Journal of the Linnean Society, 2005,148, 101–116. [ABSTRACT FROM AUTHOR]

Seventy-four nucleotide sequences from the ITS regions of nuclear ribosomal DNA and 76 from the trnL-trnF spacer of chloroplast DNA were used to address the origin of tetraploid Cardamine amporitana, the conspecifity of central Italian and northeastern Spanish populations, and the possible cause for such geographic disjunction. Because of the complex lineage relationships in Cardamine, the sampling included 22 taxa. In the results, both data sets are highly congruent in supporting a close relationship of C. amporitana to the widespread Eurasian C. amara. Low genetic variability in northeastern Spanish populations of C. amporitana suggests long-distance dispersal from central Italy. The interior position of the single northeastern Spanish haplotype in a statistical parsimony network of trnL-trnF haplotypes however does not support this scenario and invokes other plausible phylogeographic explanations. The disappearance of geographically intermediate populations and genetic impoverishment by migration and isolation, both probably associated with Quaternary climatic oscillations, appears as an alternative hypothesis to explain the phylogeographic pattern. A recent hybridization event is reported between C. amporitana and a diploid from the C. pratensis group in central Italy on the basis of additive polymorphisms in ITS for all the 22 distinguishing nucleotides. [ABSTRACT FROM AUTHOR]

• Background and Aims Diploid representatives from the related polyploid complexes of Cardamine amara, C. pratensis and C. raphanifolia (Brassicaceae), were studied to elucidate phylogenetic relationships among the complexes and among the individual taxa included.• Methods Two independent molecular data sets were used: nucleotide sequences from the internal transcribed spacers (ITS) of nrDNA, and amplified fragment length polymorphism (AFLP) markers. Seventeen diploid taxa from the studied groups were sampled.• Key Results Both ITS and AFLP analyses provided congruent results in inferred relationships, and revealed two main lineages. While the C. amara group, consisting of C. wiedemanniana and four subspecies of C. amara, was resolved as a well‐supported monophyletic group, taxa from the C. pratensis and C. tenera groups (the latter representing diploid taxa of the complex of C. raphanifolia) all appeared together in a single clade/cluster with no support for the recognition of either of the groups. Intra‐individual polymorphisms and patterns of nucleotide variation in the ITS region in C. uliginosa and C. tenera, together with the distribution of AFLP bands, indicate ancient hybridization and introgression among these Caucasian diploids.• Conclusions The lack of supported hierarchical structure suggests that extensive reticulate evolution between these groups, even at the diploid level, has occurred (although an alternative explanation, namely ancestral polymorphism in ITS data, cannot be completely excluded). Several implications for the investigation of the polyploid complexes of concern are drawn. When tracing origins of polyploid taxa, a much more complex scenario should be expected, taking into account all relatives as potential parents, irrespective of the group in which they are classified. [ABSTRACT FROM AUTHOR]

Focuses on the study of tetrapoid Cardamine amara by botanists in the Mediterranean Region. Examination of the species through morphometric and amplified fragment length polymorphism; Variation in the morphology of C. amara throughout its distribution in the European continent; Resolution on the taxonomic position of Central Italian populations usually placed within C. amara.

Investigates representative Cardamine pratensis from the Iberian Peninsula using karyological, morphometric and molecular analyses. Description of species C. castellana; Variation of chromosome numbers; Re-evaluation of populations.