Genomic DNA base composition (GC content) is predicted to significantly affect genome functioning and species ecology. Although several hypotheses have been put forward to address the biological impact of GC content variation in microbial and vertebrate organisms, the biological significance of GC content diversity in plants remains unclear because of a lack of sufficiently robust genomic data. Using flow cytometry, we report genomic GC contents for 239 species representing 70 of 78 monocot families and compare them with genomic characters, a suite of life history traits and climatic niche data using phylogeny-based statistics. GC content of monocots varied between 33.6% and 48.9%, with several groups exceeding the GC content known for any other vascular plant group, highlighting their unusual genome architecture and organization. GC content showed a quadratic relationship with genome size, with the decreases in GC content in larger genomes possibly being a consequence of the higher biochemical costs of GC base synthesis. Dramatic decreases in GC content were observed in species with holocentric chromosomes, whereas increased GC content was documented in species able to grow in seasonally cold and/or dry climates, possibly indicating an advantage of GC-rich DNA during cell freezing and desiccation. We also show that genomic adaptations associated with changing GC content might have played a significant role in the evolution of the Earth's contemporary biota, such as the rise of grass-dominated biomes during the mid-Tertiary. One of the major selective advantages of GC-rich DNA is hypothesized to be facilitating more complex gene regulation.

• Klíčová slova
• Poaceae, genome size evolution, geographical stratification, phylogenetic regression, plant genome,
• MeSH
• aklimatizace genetika   MeSH
• chromozomy rostlin genetika   MeSH
• DNA rostlinná chemie   genetika   MeSH
• ekosystém MeSH
• fylogeneze MeSH
• genetická variace MeSH
• genom rostlinný MeSH
• lipnicovité chemie   klasifikace   genetika   MeSH
• Magnoliopsida chemie   klasifikace   genetika   MeSH
• molekulární evoluce * MeSH
• zastoupení bazí MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• DNA rostlinná MeSH

The plant hormones cytokinins are a convenient target of genetic manipulations that bring benefits in biotechnological applications. The present work demonstrates the importance of the subcellular compartmentalization of cytokinins on the model dicot plant Arabidopsis thaliana and monocot crop Hordeum vulgare. The method of protoplast and vacuole isolation combined with precise cytokinin analysis and recovery assay of a vacuolar marker protein were used to quantify the contents of individual cytokinin forms in the leaf extracellular space, cell interior and vacuole. The data obtained for wild type plants and in each case a specific mutant line allow comparing the effect of genetic manipulations on the hormone distribution and homeostatic balance of cytokinins in the modified plants.

• MeSH
• Arabidopsis genetika   metabolismus   MeSH
• biotechnologie MeSH
• cytokininy metabolismus   MeSH
• extracelulární prostor metabolismus   MeSH
• geneticky modifikované rostliny MeSH
• intracelulární prostor metabolismus   MeSH
• ječmen (rod) růst a vývoj   metabolismus   MeSH
• kompartmentace buňky MeSH
• listy rostlin metabolismus   MeSH
• membránové transportní proteiny genetika   metabolismus   MeSH
• mutace MeSH
• proteiny huseníčku genetika   metabolismus   MeSH
• protoplasty metabolismus   MeSH
• regulátory růstu rostlin metabolismus   MeSH
• vakuoly metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• cytokininy MeSH
• membránové transportní proteiny MeSH
• proteiny huseníčku MeSH
• regulátory růstu rostlin MeSH
• Wat1 protein, Arabidopsis MeSH Prohlížeč

Members of the genus Heliconia L. (Heliconiaceae) have evolved complex interactions with both insect herbivores and hummingbird pollinators in tropical forests and secondary growth where they are abundant and diverse. Many of these same species have also been cultivated as ornamentals around the world for hundreds of years because of their extraordinary colors and forms. Because of the large size, fleshy nature, and tropical distribution, and despite a long taxonomic history, the classification and phylogenetic relationships of species of Heliconia have not received sufficient attention to date. No complete classification has been published for the entire genus, although some preliminary attempts have been offered. In this paper we used tissue sampled from field and herbarium collections of 136 species for genomic sequencing to determine the phylogenetic patterns within Heliconia, which then served as the basis for a new evolutionary classification of the genus. This new classification, which is based on extensive field work and the phylogenomic insights provided here, includes 187 currently recognized species. The new classification of Heliconia is composed of 17 sections in five subgenera with all groups well-supported in the phylogenomic analysis. Four subgenera are each composed of two sections and one subgenus includes nine sections. One subgenus and 10 sections are described as new.

• Klíčová slova
• Classification, Zingiberales bait set, phylogenomics, target enrichment, tropical,
• Publikační typ
• časopisecké články MeSH

Plant variation in nutrient concentrations encompasses two major axes. The first is connected to nitrogen (N) and phosphorus (P), reflects growth rate and has been designated as the leaf economics spectrum (LES) while the second follows the gradient in calcium (Ca) and magnesium (Mg) and mirrors cell structural differences. Here, we tested in grasslands whether the sum Ca + Mg concentrations is a better indicator of digestibility than LES constituents. Structural equation modelling revealed that the total effect size of N (0.30) on digestibility was much lower than that of Ca + Mg (0.58). The N effect originated predominantly from sampling date (biomass ageing), while the Ca + Mg effect largely from phylogenetic composition (proportion of monocots). Thus, plant variation in partially substitutable divalent cations seems to play a significant role in biomass digestion by ruminants. This finding contests, together with litter decomposition studies, the prominent role of the LES for understanding both fundamental ecological processes.

• Klíčová slova
• asterids, biomass, dicots, leaf dry matter content, leaf economics spectrum, monocots, nitrogen, phosphorus, rosids, rumen liquor,
• MeSH
• dusík MeSH
• fosfor MeSH
• fylogeneze MeSH
• fyziologie rostlin MeSH
• hořčík * MeSH
• listy rostlin MeSH
• rostliny MeSH
• vápník * MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• dusík MeSH
• fosfor MeSH
• hořčík * MeSH
• vápník * MeSH

Heterologous synthesis of proteins or peptides in plant-based systems, referred to as plant molecular farming, is a practical and safe approach for the large-scale and cost-effective production of therapeutic biomolecules. In this context, monocotyledonous plants, and especially cereals, have been considered attractive vehicles for producing high-value recombinant proteins. The endosperm, as the largest grain storage compartment, offers an appropriate environment for long-lasting protein accumulation. During the last decades, fascinating progress has been achieved in the gene transfer technology and genetic manipulation of the monocot crops using either Agrobacterium tumefaciens or direct gene transfer by biolistic methods. Our group has recently expressed biologically active recombinant human peptide cathelicidin in barley grains using endosperm-specific promoter and brought such engineered lines to field cultivation under current EU regulations for genetically modified organisms. This article reviews the most recent advances and strategies for the production of biopharmaceutical proteins in transgenic monocots, highlighting various aspects involved in recombinant protein accumulation in grains, and discussing current bottlenecks and perspectives for the biosynthesis of therapeutic molecules using different monocot plant platforms.

• Klíčová slova
• Agrobacterium-mediated transformation, Cereals, Endosperm-specific promoters, Molecular farming, Post-translational modifications,
• MeSH
• Agrobacterium tumefaciens genetika   MeSH
• geneticky modifikované rostliny genetika   metabolismus   MeSH
• ječmen (rod) * genetika   metabolismus   MeSH
• jedlá semena genetika   MeSH
• lidé MeSH
• molekulární farmaření * MeSH
• rekombinantní proteiny genetika   metabolismus   MeSH
• zemědělské plodiny genetika   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Názvy látek
• rekombinantní proteiny MeSH

Genome size variation is a crucial aspect of plant evolution, influenced by a complex interplay of factors. Repetitive elements, which are fundamental components of genomic architecture, often play a role in genome expansion by selectively amplifying specific repeat motifs. This study focuses on Amomum, a genus in the ginger family (Zingiberaceae), known for its 4.4-fold variation in genome size. Using a robust methodology involving PhyloNet reconstruction, RepeatExplorer clustering, and repeat similarity-based phylogenetic network construction, we investigated the repeatome composition, analyzed repeat dynamics, and identified potential hybridization events within the genus. Our analysis confirmed the presence of four major infrageneric clades (A-D) within Amomum, with clades A-C exclusively comprising diploid species (2n = 48) and clade D encompassing both diploid and tetraploid species (2n = 48 and 96). We observed an increase in the repeat content within the genus, ranging from 84% to 89%, compared to outgroup species with 75% of the repeatome. The SIRE lineage of the Ty1-Copia repeat superfamily was prevalent in most analyzed ingroup genomes. We identified significant difference in repeatome structure between the basal Amomum clades (A, B, C) and the most diverged clade D. Our investigation revealed evidence of ancient hybridization events within Amomum, coinciding with a substantial proliferation of multiple repeat groups. This finding supports the hypothesis that ancient hybridization is a driving force in the genomic evolution of Amomum. Furthermore, we contextualize our findings within the broader context of genome size variations and repeatome dynamics observed across major monocot lineages. This study enhances our understanding of evolutionary processes within monocots by highlighting the crucial roles of repetitive elements in shaping genome size and suggesting the mechanisms that drive these changes.

• Klíčová slova
• 5S rDNA, Zingiberaceae, genome evolution, genome size, interspecific hybridization, phylogeny, repeatome, repetitive DNA,
• Publikační typ
• časopisecké články MeSH

In a recent addendum, Oren Tzfadia and Gad Galili (PSB 2014; 9:e26732) showed that several Arabidopsis exocyst subunits possess consensus Atg8-interacting motifs (AIMs), which may mediate their interaction with the autophagy-associated Atg8 protein, providing thus a mechanistic base for participation of exocyst (sub)complexes in autophagy. However, the bioinformatically identified AIMs are short peptide motifs that may occur by chance. We thus performed an exhaustive search in a large collection of plant exocyst-derived sequences from our previous bioinformatic study and found that AIMs are over-represented among exocyst subunits of all lineages examined, including moss and club moss, compared with a representative sample of the Arabidopsis proteome. This is consistent with the proposed exocyst AIMs being biologically meaningful and evolutionarily ancient. Moreover, among the numerous EXO70 paralogs, the monocot-specific EXO70F clade appears to be exempt from the general AIM enrichment, suggesting a modification of the autophagy connection in a subset of exocyst variants.

• Klíčová slova
• Atg8, EXO70, Physcomitrella, Selaginella, autophagy, dicots, evolution, exocyst, monocots, protein sequence patterns,
• MeSH
• aminokyselinové motivy MeSH
• Arabidopsis cytologie   metabolismus   MeSH
• autofagie * MeSH
• fylogeneze MeSH
• podjednotky proteinů chemie   metabolismus   MeSH
• rostlinné proteiny chemie   metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• podjednotky proteinů MeSH
• rostlinné proteiny MeSH

During our initial phylogenetic study of the monocot genus Erythronium (Liliaceae), we observed peculiar eudicot-type internal transcribed spacer (ITS) sequences in a dataset derived from genomic DNA of Erythronium dens-canis. This raised the possibility of horizontal transfer of a eudicot alien ribosomal DNA (rDNA) into the Erythronium genome. In this work we aimed to support this hypothesis by carrying out genomic, molecular, and cytogenetic analyses. Genome skimming coupled by PacBio HiFi sequencing of a bacterial artificial chromosome clone derived from flow-sorted nuclei was used to characterise the alien 45S rDNA. Integration of alien rDNA in the recipient genome was further proved by Southern blotting and fluorescence in situ hybridization using specific probes. Alien rDNA, nested among Potentilla species in phylogenetic analysis, likely entered the Erythronium lineage in the common ancestor of E. dens-canis and E. caucasicum. Transferred eudicot-type rDNA preserved its tandemly arrayed feature on a single chromosome and was found to be transcribed in the monocot host, albeit much less efficiently than the native counterpart. This study adds a new example to the rarely documented nuclear-to-nuclear jumps of DNA between eudicots and monocots while holding the scientific community continually in suspense about the mode of DNA transfer.

• Klíčová slova
• Erythronium, Potentilla, horizontal gene transfer, internal transcribed spacer, lateral gene transfer, rDNA, ribosomal RNA genes,
• MeSH
• fylogeneze MeSH
• hybridizace in situ fluorescenční MeSH
• liliovité * MeSH
• mezerníky ribozomální DNA genetika   MeSH
• Potentilla * genetika   MeSH
• ribozomální DNA genetika   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• mezerníky ribozomální DNA MeSH
• ribozomální DNA MeSH

Efficient water management is essential for the survival of vascular plants under drought stress. While interrelations among drought stress, plant anatomy and physiological functions have been described in woody dicots, similar research is very limited for non-palm arborescent and shrubby monocots despite their generally high drought tolerance. In this study, potted transplants of Dracaena marginata Lam. in primary growth stage were exposed to several short- and long-term drought periods. Continuous measurements of sap flow and stem diameter, the evaluation of capacitance and leaf conductance, the quantification of non-structural carbohydrates (NSC), and organ-specific anatomical analyses were performed to reveal the mechanisms promoting plant resistance to limited soil moisture. The plants showed sensitive stomata regulation in the face of drying soil, but only intermediate resistance to water loss through cuticular transpiration. The water losses were compensated by water release from stem characterized by densely interconnected, parenchyma-rich ground tissue and considerable hydraulic capacitance. Our results suggest that the high concentration of osmotically active NSC in aboveground organs combined with the production of root pressures supported water uptake and the restoration of depleted reserves after watering. The described anatomical features and physiological mechanisms impart D. marginata with high resistance to irregular watering and long-term water scarcity. These findings should help to improve predictions with respect to the impacts of droughts on this plant group.

• Klíčová slova
• hydraulic capacitance, non-structural carbohydrates, sap flow, stomatal conductance, water potential, xylem,
• MeSH
• Dracaena fyziologie   MeSH
• listy rostlin fyziologie   MeSH
• období sucha * MeSH
• průduchy rostlin fyziologie   MeSH
• stonky rostlin fyziologie   MeSH
• transpirace rostlin MeSH
• voda fyziologie   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• voda MeSH

Inducible systems for transgene expression activated by a chemical inducer or an inducer of non-plant origin are desirable tools for both basic plant research and biotechnology. Although, the technology has been widely exploited in dicotyledonous model plants such as Arabidopsis, it has not been optimised for use with the monocotyledonous model species, namely rice. We have adapted the dexamethasone-inducible pOp6/LhGR system for rice and the results indicated that it is fast, sensitive and tightly regulated, with high levels of induction that remain stable over several generations. Most importantly, we have shown that the system does not cause negative growth defects in vitro or in soil grown plants. Interestingly in the process of testing, we found that another steroid, triamcinolone acetonide, is a more potent inducer in rice than dexamethasone. We present serious considerations for the construct design to avoid undesirable effects caused by the system in plants, leakiness and possible silencing, as well as simple steps to maximize translation efficiency of a gene of interest. Finally, we compare the performance of the pOp6/LhGR system with other chemically inducible systems tested in rice in terms of the properties of an ideal inducible system.

• Klíčová slova
• Chemically inducible gene expression, Dexamethasone, GVG, Glucocorticoid, Monocots, Promotor, XVE,
• MeSH
• dexamethason metabolismus   MeSH
• regulace genové exprese u rostlin účinky léků   MeSH
• rostlinné geny MeSH
• rýže (rod) genetika   růst a vývoj   metabolismus   MeSH
• transgeny MeSH
• vývoj rostlin účinky léků   genetika   MeSH
• zemědělské plodiny genetika   růst a vývoj   metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• dexamethason MeSH