Meiotic recombination is a critical process for plant breeding, as it creates novel allele combinations that can be exploited for crop improvement. In wheat, a complex allohexaploid that has a diploid-like behaviour, meiotic recombination between homoeologous or alien chromosomes is suppressed through the action of several loci. Here, we report positional cloning of Pairing homoeologous 2 (Ph2) and functional validation of the wheat DNA mismatch repair protein MSH7-3D as a key inhibitor of homoeologous recombination, thus solving a half-century-old question. Similar to ph2 mutant phenotype, we show that mutating MSH7-3D induces a substantial increase in homoeologous recombination (up to 5.5 fold) in wheat-wild relative hybrids, which is also associated with a reduction in homologous recombination. These data reveal a role for MSH7-3D in meiotic stabilisation of allopolyploidy and provides an opportunity to improve wheat's genetic diversity through alien gene introgression, a major bottleneck facing crop improvement.

• MeSH
• alely MeSH
• chiméra MeSH
• chromozomy rostlin chemie   MeSH
• DNA rostlinná genetika   metabolismus   MeSH
• fyzikální mapování chromozomů MeSH
• homologní rekombinace * MeSH
• meióza MeSH
• mutace MeSH
• oprava chybného párování bází DNA MeSH
• ploidie MeSH
• pšenice genetika   metabolismus   MeSH
• regulace genové exprese u rostlin * MeSH
• rostlinné proteiny genetika   metabolismus   MeSH
• šlechtění rostlin metody   MeSH
• žito genetika   metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Characterization of protein-protein and protein-DNA interactions is critical to understand mechanisms governing the biology of cells. Here we describe optimized methods and their mutual combinations for this purpose: bimolecular fluorescence complementation (BiFC), co-immunoprecipitation (Co-IP), yeast two-hybrid systems (Y2H), and chromatin immunoprecipitation (ChIP). These improved protocols detect trimeric complexes in which two proteins of interest interact indirectly via a protein sandwiched between them. They also allow isolation of low-abundance chromatin proteins and confirmation that proteins of interest are associated with specific DNA sequences, for example telomeric tracts. Here we describe these methods and their application to map interactions of several telomere- and telomerase-associated proteins and to purify a sufficient amount of chromatin from Arabidopsis thaliana for further investigations (e.g., next-generation sequencing, hybridization).

• MeSH
• Arabidopsis genetika   metabolismus   MeSH
• buněčné jádro metabolismus   MeSH
• chromatin metabolismus   MeSH
• chromatinová imunoprecipitace metody   MeSH
• DNA rostlinná metabolismus   MeSH
• DNA vazebné proteiny izolace a purifikace   metabolismus   MeSH
• imunoprecipitace metody   MeSH
• mapování interakce mezi proteiny metody   MeSH
• optické zobrazování metody   MeSH
• proteiny huseníčku genetika   metabolismus   MeSH
• techniky dvojhybridového systému MeSH
• telomerasa metabolismus   MeSH
• telomery metabolismus   MeSH
• vazba proteinů MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Sugarcane (Saccharum spp.) is a globally important crop for sugar and bioenergy production. Its highly polyploid, complex genome has hindered progress in understanding its molecular structure. Flow cytometric sorting and analysis has been used in other important crops with large genomes to dissect the genome into component chromosomes. Here we present for the first time a method to prepare suspensions of intact sugarcane chromosomes for flow cytometric analysis and sorting. Flow karyotypes were generated for two S. officinarum and three hybrid cultivars. Five main peaks were identified and each genotype had a distinct flow karyotype profile. The flow karyotypes of S. officinarum were sharper and with more discrete peaks than the hybrids, this difference is probably due to the double genome structure of the hybrids. Simple Sequence Repeat (SSR) markers were used to determine that at least one allelic copy of each of the 10 basic chromosomes could be found in each peak for every genotype, except R570, suggesting that the peaks may represent ancestral Saccharum sub genomes. The ability to flow sort Saccharum chromosomes will allow us to isolate and analyse chromosomes of interest and further examine the structure and evolution of the sugarcane genome.

• MeSH
• alely MeSH
• buněčný cyklus účinky léků   genetika   MeSH
• chromozomy rostlin genetika   MeSH
• DNA rostlinná metabolismus   MeSH
• fluorescence MeSH
• genom rostlinný * MeSH
• hydroxymočovina farmakologie   MeSH
• karyotyp MeSH
• kinetika MeSH
• kořeny rostlin účinky léků   MeSH
• polyploidie * MeSH
• průtoková cytometrie metody   MeSH
• Saccharum účinky léků   genetika   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

The carnivorous plant genus Utricularia L. (bladderwort) comprises about 240 species distributed worldwide and is traditionally classified into two subgenera (Polypompholyx and Utricularia) and 35 sections, based mainly on general and trap morphology. It is one out of the largest carnivorous genera, representing ca. 30% of all carnivorous plant species, and is also the most widely distributed. According to previous phylogenetic studies, most infrageneric sections are monophyletic, but there are several incongruences considering their relationships and also the dissenting position of some species as a result of a too few (mostly one or two) molecular markers analyzed. Thus, here we present a multilocus phylogeny for Utricularia species with a wide taxonomic sampling (78 species and 115 accessions) based on six plastid (rbcL, matK, rpl20-rps12, rps16, trnL-F) and nuclear DNA (ITS region) sequences. The aim is to reconstruct a well-resolved tree to propose evolutionary and biogeographic hypotheses for the radiation of lineages with inferences about the divergence times of clades using a molecular clock approach.

• MeSH
• Bayesova věta MeSH
• biologická evoluce MeSH
• buněčné jádro genetika   MeSH
• DNA rostlinná chemie   izolace a purifikace   metabolismus   MeSH
• fylogeneze MeSH
• hluchavkotvaré klasifikace   genetika   MeSH
• plastidy genetika   MeSH
• ribulosa-1,5-bisfosfát-karboxylasa klasifikace   genetika   metabolismus   MeSH
• rostlinné proteiny klasifikace   genetika   metabolismus   MeSH
• sekvence nukleotidů MeSH
• sekvenční analýza DNA MeSH
• sekvenční seřazení MeSH
• Publikační typ
• časopisecké články MeSH

Satellite DNA, a class of repetitive sequences forming long arrays of tandemly repeated units, represents substantial portions of many plant genomes yet remains poorly characterized due to various methodological obstacles. Here we show that the genome of the field bean (Vicia faba, 2n = 12), a long-established model for cytogenetic studies in plants, contains a diverse set of satellite repeats, most of which remained concealed until their present investigation. Using next-generation sequencing combined with novel bioinformatics tools, we reconstructed consensus sequences of 23 novel satellite repeats representing 0.008-2.700% of the genome and mapped their distribution on chromosomes. We found that in addition to typical satellites with monomers hundreds of nucleotides long, V. faba contains a large number of satellite repeats with unusually long monomers (687-2033 bp), which are predominantly localized in pericentromeric regions. Using chromatin immunoprecipitation with CenH3 antibody, we revealed an extraordinary diversity of centromeric satellites, consisting of seven repeats with chromosome-specific distribution. We also found that in spite of their different nucleotide sequences, all centromeric repeats are replicated during mid-S phase, while most other satellites are replicated in the first part of late S phase, followed by a single family of FokI repeats representing the latest replicating chromatin.

• MeSH
• anotace sekvence MeSH
• centromera metabolismus   MeSH
• chromatinová imunoprecipitace MeSH
• DNA rostlinná genetika   metabolismus   MeSH
• genom rostlinný genetika   MeSH
• mapování chromozomů metody   MeSH
• molekulární evoluce MeSH
• načasování replikace DNA genetika   MeSH
• satelitní DNA genetika   MeSH
• sekvenční analýza DNA MeSH
• Vicia faba genetika   metabolismus   MeSH
• výpočetní biologie MeSH
• vysoce účinné nukleotidové sekvenování MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Frullania subgenus Microfrullania is a clade of ca. 15 liverwort species occurring in Australasia, Malesia, and southern South America. We used combined nuclear and chloroplast sequence data from 265 ingroup accessions to test species circumscriptions and estimate the biogeographic history of the subgenus. With dense infra-specific sampling, we document an important role of long-distance dispersal in establishing phylogeographic patterns of extant species. At deeper time scales, a combination of phylogenetic analyses, divergence time estimation and ancestral range estimation were used to reject vicariance and to document the role of long-distance dispersal in explaining the evolution and biogeography of the clade across the southern Hemisphere. A backbone phylogeny for the subgenus is proposed, providing insight into evolution of morphological patterns and establishing the basis for an improved sectional classification of species within Microfrullania. Several species complexes are identified, the presence of two undescribed but genetically and morphologically distinct species is noted, and previously neglected names are discussed.

• MeSH
• biologická evoluce MeSH
• DNA rostlinná izolace a purifikace   metabolismus   MeSH
• Frullania anatomie a histologie   klasifikace   genetika   MeSH
• fylogeneze MeSH
• fylogeografie MeSH
• genetické lokusy MeSH
• sekvenční analýza DNA MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Australasie MeSH
• Jižní Amerika MeSH

The rapidly proliferating cells in plant meristems must be protected from genome damage. Here, we show that the regulatory role of the Arabidopsis RETINOBLASTOMA RELATED (RBR) in cell proliferation can be separated from a novel function in safeguarding genome integrity. Upon DNA damage, RBR and its binding partner E2FA are recruited to heterochromatic γH2AX-labelled DNA damage foci in an ATM- and ATR-dependent manner. These γH2AX-labelled DNA lesions are more dispersedly occupied by the conserved repair protein, AtBRCA1, which can also co-localise with RBR foci. RBR and AtBRCA1 physically interact in vitro and in planta Genetic interaction between the RBR-silenced amiRBR and Atbrca1 mutants suggests that RBR and AtBRCA1 may function together in maintaining genome integrity. Together with E2FA, RBR is directly involved in the transcriptional DNA damage response as well as in the cell death pathway that is independent of SOG1, the plant functional analogue of p53. Thus, plant homologs and analogues of major mammalian tumour suppressor proteins form a regulatory network that coordinates cell proliferation with cell and genome integrity.

• MeSH
• Arabidopsis genetika   MeSH
• ATM protein metabolismus   MeSH
• DNA rostlinná metabolismus   MeSH
• kontrolní body buněčného cyklu * MeSH
• oprava DNA * MeSH
• poškození DNA * MeSH
• proteiny huseníčku metabolismus   MeSH
• regulace genové exprese u rostlin * MeSH
• transkripční faktory E2F metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH

BACKGROUND AND AIMS: In ferns, apomixis is an important mode of asexual reproduction. Although the mechanisms of fern reproduction have been studied thoroughly, most previous work has focused on cases in which ferns reproduce either exclusively sexually or exclusively asexually. Reproduction of ferns with potentially mixed systems and inheritance of apomixis remains largely unknown. This study addresses reproduction of the pentaploid Dryopteris × critica, a hybrid of triploid apomictic D. borreri and tetraploid sexual D. filix-mas. METHODS: Spore size, abortion percentage and number of spores per sporangium were examined in pentaploid plants of D. × critica grown in an experimental garden. The sporangial content of leaf segments was cultivated on an agar medium, and DNA ploidy levels were estimated by DAPI flow cytometry in 259 gametophytes or sporophytes arising from the F2 generation of the pentaploid hybrid. KEY RESULTS: The hybrid is partly fertile (89-94% of aborted spores) and shows unstable sporogenesis with sexual and apomictic reproduction combined. The number of spores per sporangium varied from approx. 31 to 64. Within a single sporangium it was possible to detect formation of either only aborted spores or various mixtures of aborted and well-developed reduced spores and unreduced diplospores. The spores germinated in viable gametophytes with two ploidy levels: pentaploid (5x, from unreduced spores) and half of that (approx. 2·5x, from reduced spores). Moreover, 2-15% of gametophytes (both 2·5x and 5x) formed a viable sporophyte of the same ploidy level due to apogamy. CONCLUSIONS: This study documents the mixed reproductive mode of a hybrid between apomictic and sexual ferns. Both sexual reduced and apomictic unreduced spores can be produced by a single individual, and even within a single sporangium. Both types of spores give rise to viable F2 generation gametophytes and sporophytes.

• MeSH
• apomixie * MeSH
• délka genomu MeSH
• DNA rostlinná metabolismus   MeSH
• Dryopteris genetika   fyziologie   MeSH
• gametogeneze rostlin genetika   fyziologie   MeSH
• genom rostlinný MeSH
• haploidie * MeSH
• klíčení MeSH
• křížení genetické MeSH
• průtoková cytometrie MeSH
• spory cytologie   fyziologie   MeSH
• tetraploidie * MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Here, we present an improved amplified fragment length polymorphism (AFLP) protocol using restriction enzymes (AscI and SbfI) that recognize 8-base pair sequences to provide alternative optimization suitable for species with a genome size over 70 Gb. This cost-effective optimization massively reduces the number of amplified fragments using only +3 selective bases per primer during selective amplification. We demonstrate the effects of the number of fragments and genome size on the appearance of nonidentical comigrating fragments (size homoplasy), which has a negative impact on the informative value of AFLP genotypes. We also present various reaction conditions and their effects on reproducibility and the band intensity of the extremely large genome of Viscum album. The reproducibility of this octo-cutter protocol was calculated using several species with genome sizes ranging from 1 Gb (Carex panicea) to 76 Gb (V. album). The improved protocol also succeeded in detecting high intraspecific variability in species with large genomes (V. album, Galanthus nivalis and Pinus pumila).

• MeSH
• analýza polymorfismu délky amplifikovaných restrikčních fragmentů metody   MeSH
• DNA rostlinná genetika   metabolismus   MeSH
• genom rostlinný * MeSH
• genotypizační techniky metody   MeSH
• reprodukovatelnost výsledků MeSH
• restrikční enzymy metabolismus   MeSH
• rostliny klasifikace   genetika   MeSH
• Publikační typ
• časopisecké články MeSH
• hodnotící studie MeSH

Telomeres and genes encoding 45S ribosomal RNA (rDNA) are frequently located adjacent to each other on eukaryotic chromosomes. Although their primary roles are different, they show striking similarities with respect to their features and additional functions. Both genome domains have remarkably dynamic chromatin structures. Both are hypersensitive to dysfunctional histone chaperones, responding at the genomic and epigenomic levels. Both generate non-coding transcripts that, in addition to their epigenetic roles, may induce gross chromosomal rearrangements. Both give rise to chromosomal fragile sites, as their replication is intrinsically problematic. However, at the same time, both are essential for maintenance of genomic stability and integrity. Here we discuss the structural and functional inter-connectivity of telomeres and rDNA, with a focus on recent results obtained in plants.

• MeSH
• chromatin chemie   metabolismus   MeSH
• DNA rostlinná chemie   metabolismus   MeSH
• epigeneze genetická MeSH
• histony genetika   metabolismus   MeSH
• nestabilita genomu MeSH
• replikace DNA MeSH
• ribozomální DNA chemie   metabolismus   MeSH
• rostliny genetika   MeSH
• telomery genetika   metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH