The centromere has a conserved function across eukaryotes; however, the associated DNA sequences exhibit remarkable diversity in both size and structure. In plants, some species possess well-defined centromeres dominated by tandem satellite repeats and centromeric retrotransposons, while others have centromeric regions composed almost entirely of retrotransposons. Using a combination of bioinformatic, molecular, and cytogenetic approaches, we analyzed the centromeric landscape of Humulus lupulus. We identified novel centromeric repeats and characterized two types of centromeric organization. Cytogenetic localization on metaphase chromosomes confirmed the genomic distribution of the major repeats and revealed unique centromeric organization specifically on chromosomes 2, 8, and Y. Two centromeric types are composed of the major repeats SaazCEN and SaazCRM1 (Ty3/Gypsy) which are further accompanied by chromosome-specific centromeric satellites, Saaz40, Saaz293, Saaz85, and HuluTR120. Chromosome 2 displays unbalanced segregation during mitosis and meiosis, implicating an important role for its centromere structure in segregation patterns. Moreover, chromosome 2-specific centromeric repeat Saaz293 is a new marker for studying aneuploidy in hops. Our findings provide new insights into chromosome segregation in hops and highlight the diversity and complexity of the centromere organization in H. lupulus.

• Klíčová slova
• Cannabaceae, asymmetric cell division, centromere, retrotransposons, sex chromosomes,
• MeSH
• centromera * genetika   MeSH
• chromozomy rostlin genetika   MeSH
• Humulus * genetika   MeSH
• meióza genetika   MeSH
• repetitivní sekvence nukleových kyselin * genetika   MeSH
• retroelementy * genetika   MeSH
• segregace chromozomů genetika   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• retroelementy * MeSH

The genomes of many plants, animals, and fungi frequently comprise dispensable B chromosomes that rely upon various chromosomal drive mechanisms to counteract the tendency of non-essential genetic elements to be purged over time. The B chromosome of rye - a model system for nearly a century - undergoes targeted nondisjunction during first pollen mitosis, favouring segregation into the generative nucleus, thus increasing their numbers over generations. However, the genetic mechanisms underlying this process are poorly understood. Here, using a newly-assembled, ~430 Mb-long rye B chromosome pseudomolecule, we identify five candidate genes whose role as trans-acting moderators of the chromosomal drive is supported by karyotyping, chromosome drive analysis and comparative RNA-seq. Among them, we identify DCR28, coding a microtubule-associated protein related to cell division, and detect this gene also in the B chromosome of Aegilops speltoides. The DCR28 gene family is neo-functionalised and serially-duplicated with 15 B chromosome-located copies that are uniquely highly expressed in the first pollen mitosis of rye.

• MeSH
• Aegilops genetika   metabolismus   MeSH
• chromozomy rostlin * genetika   MeSH
• karyotypizace MeSH
• mitóza * genetika   MeSH
• nondisjunkce genetická MeSH
• pyl genetika   MeSH
• regulace genové exprese u rostlin MeSH
• rostlinné geny MeSH
• rostlinné proteiny genetika   metabolismus   MeSH
• žito * genetika   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• rostlinné proteiny MeSH

Grasspea (Lathyrus sativus L.) is an underutilised but promising legume crop with tolerance to a wide range of abiotic and biotic stress factors, and potential for climate-resilient agriculture. Despite a long history and wide geographical distribution of cultivation, only limited breeding resources are available. This paper reports a 5.96 Gbp genome assembly of grasspea genotype LS007, of which 5.03 Gbp is scaffolded into 7 pseudo-chromosomes. The assembly has a BUSCO completeness score of 99.1% and is annotated with 31719 gene models and repeat elements. This represents the most contiguous and accurate assembly of the grasspea genome to date.

• MeSH
• chromozomy rostlin * genetika   MeSH
• genom rostlinný * MeSH
• Lathyrus * genetika   MeSH
• Publikační typ
• časopisecké články MeSH
• dataset MeSH

Long terminal repeat (LTR) retrotransposons constitute a predominant class of repetitive DNA elements in most plant genomes. With the increasing number of sequenced plant genomes, there is an ongoing demand for computational tools facilitating efficient annotation and classification of LTR retrotransposons in plant genome assemblies. Herein, we introduce DANTE, a computational pipeline for Domain-based ANnotation of Transposable Elements, designed for sensitive detection of these elements via their conserved protein domain sequences. The identified protein domains are subsequently inputted into the DANTE_LTR pipeline to annotate complete element sequences by detecting their structural features, such as LTRs, in adjacent genomic regions. Leveraging domain sequences allows for precise classification of elements into phylogenetic lineages, offering a more granular annotation compared with coarser conventional superfamily-based classification methods. The efficiency and accuracy of this approach were evidenced via annotation of LTR retrotransposons in 93 plant genomes. Results were benchmarked against several established pipelines, showing that DANTE_LTR is capable of identifying significantly more intact LTR retrotransposons. DANTE and DANTE_LTR are provided as user-friendly Galaxy tools accessible via a public server (https://repeatexplorer-elixir.cerit-sc.cz), installable on local Galaxy instances from the Galaxy tool shed or executable from the command line.

• Publikační typ
• časopisecké články MeSH

Centromere is the chromosomal site of kinetochore assembly and microtubule attachment for chromosome segregation. Given its importance, markers that allow specific labeling of centromeric chromatin throughout the cell cycle and across all chromosome types are sought for facilitating various centromere studies. Antibodies against the N-terminal region of CENH3 are commonly used for this purpose, since CENH3 is the near-universal marker of functional centromeres. However, because the N-terminal region of CENH3 is highly variable among plant species, antibodies directed against this region usually function only in a small group of closely related species. As a more versatile alternative, we present here antibodies targeted to the conserved domains of two outer kinetochore proteins, KNL1 and NDC80. Sequence comparison of these domains across more than 350 plant species revealed a high degree of conservation, particularly within a six amino acid motif, FFGPVS in KNL1, suggesting that both antibodies would function in a wide range of plant species. This assumption was confirmed by immunolabeling experiments in angiosperm (monocot and dicot) and gymnosperm species, including those with mono-, holo-, and meta-polycentric chromosomes. In addition to centromere labeling on condensed chromosomes during cell division, both antibodies detected the corresponding regions in the interphase nuclei of most species tested. These results demonstrated that KNL1 and NDC80 are better suited for immunolabeling centromeres than CENH3, because antibodies against these proteins offer incomparably greater versatility across different plant species which is particularly convenient for studying the organization and function of the centromere in non-model species.

• Klíčová slova
• CENH3, Centromere, KNL1, NDC80, immunolabeling, kinetochore,
• MeSH
• centromera * MeSH
• chromatin MeSH
• kinetochory * MeSH
• rostlinné proteiny * genetika   MeSH
• segregace chromozomů MeSH
• sekvence aminokyselin MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• chromatin MeSH
• rostlinné proteiny * MeSH