An endophytic fungus designated as EIT4T (MCC 9756T) was isolated from the asymptomatic stem tissue of Ephedra gerardiana collected from the Kargil district of Ladakh Union territory, India. Phylogenetic analysis based on concatenated nuclear ribosomal ITS (internal transcribed spacer) and LSU (large ribosomal subunit) sequence datasets revealed its placement within the genus Astragalicola. However, it formed a separate clade exhibiting strong bootstrap support value (80%). The highest nrITS sequence similarity between EIT4T and species of Astragalicola was 95.19% (A. vasilyevae) and 94.26% (A. amorpha), while nrLSU sequence similarity was 99.27% (A. amorpha). Morphologically, EIT4T differs from the other species of Astragalicola in having larger sub-globose to pyriform conidiomata, smaller and mostly unbranched conidiophores, and polymorphic translucent conidia with two terminal guttules. Based on combined cultural, micromorphological, molecular, and phylogenetic analyses, EIT4T represents a novel species in the genus Astragalicola proposed here as Astragalicola ephedrae sp. nov. Detailed description and illustrations of the novel species are provided. The type strain is EIT4T (= MCC 9756 T = MN29T).
- MeSH
- Ascomycota * MeSH
- DNA bakterií MeSH
- Ephedra * MeSH
- fylogeneze MeSH
- mastné kyseliny analýza MeSH
- RNA ribozomální 16S MeSH
- sekvenční analýza DNA MeSH
- techniky typizace bakterií MeSH
- zastoupení bazí MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Indie MeSH
INTRODUCTION: Gnetophytes, comprising the genera Ephedra, Gnetum and Welwitschia, are an understudied, enigmatic lineage of gymnosperms with a controversial phylogenetic relationship to other seed plants. Here we examined the organization of ribosomal DNA (rDNA) across representative species. METHODS: We applied high-throughput sequencing approaches to isolate and reconstruct rDNA units and to determine their intragenomic homogeneity. In addition, fluorescent in situ hybridization and Southern blot hybridization techniques were used to reveal the chromosome and genomic organization of rDNA. KEY RESULTS: The 5S and 35S rRNA genes were separate (S-type) in Gnetum montanum, Gnetum gnemon and Welwitschia mirabilis and linked (L-type) in Ephedra altissima. There was considerable variability in 5S rDNA abundance, ranging from as few as ~4000 (W. mirabilis) to >100 000 (G. montanum) copies. A similar large variation was also observed in 5S rDNA locus numbers (two to 16 sites per diploid cell). 5S rRNA pseudogenes were interspersed between functional genes forming a single unit in E. altissima and G. montanum. Their copy number was comparable or even higher than that of functional 5S rRNA genes. In E. altissima internal transcribed spacers of 35S rDNA were long and intrinsically repetitive while in G. montanum and W. mirabilis they were short without the subrepeats. CONCLUSIONS: Gnetophytes are distinct from other gymnosperms and angiosperms as they display surprisingly large variability in rDNA organization and rDNA copy and locus numbers between genera, with no relationship between copy numbers and genome sizes apparent. Concerted evolution of 5S rDNA units seems to have led to the amplification of 5S pseudogenes in both G. montanum and E. altissima. Evolutionary patterns of rDNA show both gymnosperm and angiosperm features underlining the diversity of the group.
Photo-reduction of O2to water mediated by flavodiiron proteins (FDPs) represents a safety valve for the photosynthetic electron transport chain in fluctuating light. So far, the FDP-mediated O2photo-reduction has been evidenced only in cyanobacteria and the moss Physcomitrella; however, a recent phylogenetic analysis of transcriptomes of photosynthetic organisms has also revealed the presence of FDP genes in several nonflowering plant groups. What remains to be clarified is whether the FDP-dependent O2photo-reduction is actually operational in these organisms. We have established a simple method for the monitoring of FDP-mediated O2photo-reduction, based on the measurement of redox kinetics of P700 (the electron donor of photosystem I) upon dark-to-light transition. The O2photo-reduction is manifested as a fast re-oxidation of P700. The validity of the method was verified by experiments with transgenic organisms, namely FDP knock-out mutants of Synechocystis and Physcomitrella and transgenic Arabidopsis plants expressing FDPs from Physcomitrella. We observed the fast P700 re-oxidation in representatives of all green plant groups excluding angiosperms. Our results provide strong evidence that the FDP-mediated O2photo-reduction is functional in all nonflowering green plant groups. This finding suggests a major change in the strategy of photosynthetic regulation during the evolution of angiosperms.
In all eukaryotes, the highly repeated 35S ribosomal DNA (rDNA) sequences encoding 18S-5.8S-26S ribosomal RNA (rRNA) typically show high levels of intragenomic uniformity due to homogenisation processes, leading to concerted evolution of 35S rDNA repeats. Here, we compared 35S rDNA divergence in several seed plants using next generation sequencing and a range of molecular and cytogenetic approaches. Most species showed similar 35S rDNA homogeneity indicating concerted evolution. However, Cycas revoluta exhibits an extraordinary diversity of rDNA repeats (nucleotide sequence divergence of different copies averaging 12 %), influencing both the coding and non-coding rDNA regions nearly equally. In contrast, its rRNA transcriptome was highly homogeneous suggesting that only a minority of genes (<20 %) encode functional rRNA. The most common SNPs were C > T substitutions located in symmetrical CG and CHG contexts which were also highly methylated. Both functional genes and pseudogenes appear to cluster on chromosomes. The extraordinary high levels of 35S rDNA diversity in C. revoluta, and probably other species of cycads, indicate that the frequency of repeat homogenisation has been much lower in this lineage, compared with all other land plant lineages studied. This has led to the accumulation of methylation-driven mutations and pseudogenisation. Potentially, the reduced homology between paralogs prevented their elimination by homologous recombination, resulting in long-term retention of rDNA pseudogenes in the genome.
- MeSH
- Cycas genetika MeSH
- DNA rostlinná genetika MeSH
- genetická transkripce genetika MeSH
- hybridizace in situ fluorescenční MeSH
- jednonukleotidový polymorfismus genetika MeSH
- mezerníky ribozomální DNA genetika MeSH
- ribozomální DNA genetika MeSH
- RNA ribozomální 18S genetika MeSH
- RNA ribozomální 5.8S genetika MeSH
- RNA ribozomální genetika MeSH
- sekvence nukleotidů MeSH
- sekvenční analýza DNA MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The RNA-directed DNA methylation (RdDM) pathway can be divided into three phases: 1) small interfering RNA biogenesis, 2) de novo methylation, and 3) chromatin modification. To determine the degree of conservation of this pathway we searched for key genes among land plants. We used OrthoMCL and the OrthoMCL Viridiplantae database to analyze proteomes of species in bryophytes, lycophytes, monilophytes, gymnosperms, and angiosperms. We also analyzed small RNA size categories and, in two gymnosperms, cytosine methylation in ribosomal DNA. Six proteins were restricted to angiosperms, these being NRPD4/NRPE4, RDM1, DMS3 (defective in meristem silencing 3), SHH1 (SAWADEE homeodomain homolog 1), KTF1, and SUVR2, although we failed to find the latter three proteins in Fritillaria persica, a species with a giant genome. Small RNAs of 24 nt in length were abundant only in angiosperms. Phylogenetic analyses of Dicer-like (DCL) proteins showed that DCL2 was restricted to seed plants, although it was absent in Gnetum gnemon and Welwitschia mirabilis. The data suggest that phases (1) and (2) of the RdDM pathway, described for model angiosperms, evolved with angiosperms. The absence of some features of RdDM in F. persica may be associated with its large genome. Phase (3) is probably the most conserved part of the pathway across land plants. DCL2, involved in virus defense and interaction with the canonical RdDM pathway to facilitate methylation of CHH, is absent outside seed plants. Its absence in G. gnemon, and W. mirabilis coupled with distinctive patterns of CHH methylation, suggest a secondary loss of DCL2 following the divergence of Gnetales.
- MeSH
- Arabidopsis genetika MeSH
- chromatin metabolismus MeSH
- cykasy genetika metabolismus MeSH
- cytosin metabolismus MeSH
- DNA řízené RNA-polymerasy metabolismus MeSH
- epigeneze genetická MeSH
- fylogeneze MeSH
- genom rostlinný MeSH
- Magnoliopsida enzymologie genetika metabolismus MeSH
- malá interferující RNA metabolismus MeSH
- malá nekódující RNA chemie MeSH
- metylace DNA * MeSH
- metylace MeSH
- ribonukleasa III klasifikace genetika MeSH
- RNA rostlin chemie metabolismus MeSH
- rostlinné geny * MeSH
- rostlinné proteiny klasifikace genetika MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
One of the ways to assess the impacts of climate change on plants is analysing their long-term phenological data. We studied phenological records of 18 common tree species and their 8 phenological phases, spanning 65 years (1946-2010) and covering the area of the Czech Republic. For each species and phenophase, we assessed the changes in its annual means (for detecting shifts in the timing of the event) and standard deviations (for detecting changes in duration of the phenophases). The prevailing pattern across tree species was that since around the year 1976, there has been a consistent advancement of the onset of spring phenophases (leaf unfolding and flowering) and subsequent acceleration of fruit ripening, and a delay of autumn phenophases (leaf colouring and leaf falling). The most considerable shifts in the timing of spring phenophases were displayed by early-successional short-lived tree species. The most pronounced temporal shifts were found for the beginning of seed ripening in conifers with an advancement in this phenophase of up to 2.2 days year⁻¹ in Scots Pine (Pinus sylvestris). With regards to the change in duration of the phenophases, no consistent patterns were revealed. The growing season has extended on average by 23.8 days during the last 35 years. The most considerable prolongation was found in Pedunculate Oak (Quercus robur): 31.6 days (1976-2010). Extended growing season lengths do have the potential to increase growth and seed productivity, but unequal shifts among species might alter competitive relationships within ecosystems.
- MeSH
- cykasy růst a vývoj MeSH
- ekosystém MeSH
- fyziologie rostlin MeSH
- klimatické změny * MeSH
- květy růst a vývoj MeSH
- listy rostlin růst a vývoj MeSH
- Magnoliopsida růst a vývoj MeSH
- ovoce růst a vývoj MeSH
- roční období MeSH
- stromy růst a vývoj MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Česká republika MeSH
Several electrical methods have been introduced as non-invasive techniques to overcome the limited accessibility to root systems. Among them, the earth impedance method (EIM) represents the most recent development. Applying an electrical field between a cormus and the rooted soil, the EIM measures the absorptive root surface area (ARSA) from grounding resistance patterns. Allometric relationships suggested that this method was a valuable tool. Crucial assumptions for the applicability of the EIM, however, have not been tested experimentally. Focusing on tree root systems, the present study assesses the applicability of the EIM. Six hypotheses, deduced from the EIM approach, were tested in several experiments and the results were compared with conventional methods. None of the hypotheses could be verified and the results allow two major conclusions. First, in terms of an analogue electrical circuit, a tree-root-soil continuum appears as a serial circuit with xylem and soil resistance being the dominant components. Allometric variation in contact resistance, with the latter being the proxy for root surface area, are thus overruled by the spatial and seasonal variation of soil and xylem resistances. Second, in a tree-root-soil continuum, distal roots conduct only a negligible portion of the electric charge. Most of charge carriers leave the root system in the proximal parts of the root-soil interface.
- MeSH
- algoritmy MeSH
- biometrie MeSH
- cykasy MeSH
- elektrická impedance MeSH
- kořeny rostlin anatomie a histologie fyziologie MeSH
- Magnoliopsida MeSH
- průmyslová hnojiva MeSH
- půda MeSH
- roční období MeSH
- stromy anatomie a histologie fyziologie MeSH
- xylém fyziologie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Vyd. 1. 258 s. : il., tab. ; 24 cm
V publikaci jsou shrnuty informace o více než 1200 rostlinných druzích představujících současné, potenciální i perspektivní surovinové zdroje farmaceutických látek.
- MeSH
- cykasy chemie MeSH
- farmaceutická chemie MeSH
- farmacie trendy MeSH
- farmakognozie MeSH
- léčivé rostliny chemie MeSH
- Magnoliopsida chemie MeSH
- Konspekt
- Botanika
- Učební osnovy. Vyučovací předměty. Učebnice
- NLK Obory
- botanika
- farmacie a farmakologie
- pedagogika
- NLK Publikační typ
- učebnice vysokých škol
Comparative analyses of lipids from fossil plants and from their extant counterparts were undertaken in order to test the taxonomic significance of lipids in palaeobotany. The comparison between lipids from a fossil Ginkgoaceae, Eretmophyllum andegavense, and its extant counterpart, Ginkgo biloba, revealed the presence of original molecules, dimethoxyalkylcoumarins, in lipids from both plants. Such compounds confirm, on chemical grounds the relationship between these extant and fossil Ginkgoaceaes. Moreover, differences in n-alkane distribution between E. andegavense and E. obtusum which are very similar morphologically, confirm that these fossil plants do not belong to the same species. Furthermore, comparative analyses of a fossil Cheirolepidiaceae, Frenelopsis alata, and its extant counterpart, the Cupressaceae Tetraclinis articulata, revealed some similarities between these two species although they do not belong to the same family. Otherwise, comparative analyses of fungi-infected and uninfected samples of F. alata demonstrated that these micro-organisms can significantly affect the chemical composition of fossil plant lipids. In conclusion, even if chemical analyses alone are not sufficient to determine the genus or species of a given fossil plant, they can precise the taxonomy of some specimens that have been previously studied by palaeobotanists.
- MeSH
- cykasy chemie MeSH
- druhová specificita MeSH
- fylogeneze MeSH
- Ginkgo biloba chemie MeSH
- houby chemie MeSH
- léčivé rostliny MeSH
- lipidy klasifikace izolace a purifikace MeSH
- listy rostlin chemie MeSH
- molekulární evoluce * MeSH
- molekulární struktura MeSH
- plynová chromatografie s hmotnostně spektrometrickou detekcí MeSH
- rostliny chemie klasifikace genetika mikrobiologie MeSH
- stonky rostlin chemie MeSH
- zkameněliny * MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- srovnávací studie MeSH
- Geografické názvy
- Česká republika MeSH
- Francie MeSH
