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MAIN CONCLUSION: Isoprenoid and aromatic cytokinins occur in poplar as free compounds and constituents of tRNA, poplar isopentenyltransferases are involved in the production of isoprenoid cytokinins, while biosynthesis of their aromatic counterparts remains unsolved. Cytokinins are phytohormones with a fundamental role in the regulation of plant growth and development. They occur naturally either as isoprenoid or aromatic derivatives, but the latter are quite rare and less studied. Here, the spatial expression of all nine isopentenyl transferase genes of Populus × canadensis cv. Robusta (PcIPTs) as analyzed by RT-qPCR revealed a tissue preference and strong differences in expression levels for the different adenylate and tRNA PcIPTs. Together with their phylogeny, this result suggests a functional diversification for the different PcIPT proteins. Additionally, the majority of PcIPT genes were cloned and expressed in Arabidopsis thaliana under an inducible promoter. The cytokinin levels measured in the Arabidopsis-overexpressing lines as well as their phenotype indicate that the studied adenylate and tRNA PcIPT proteins are functional in vivo and thus will contribute to the cytokinin pool in poplar. We screened the cytokinin content in leaves of 12 Populus species by ultra-high performance-tandem mass spectrometry (UHPLC-MS/MS) and discovered that the capacity to produce not only isoprenoid, but also aromatic cytokinins is widespread amongst the Populus accessions studied. Important for future studies is that the levels of aromatic cytokinins transiently increase after daybreak and are much higher in older plants.
- MeSH
- alkyltransferasy a aryltransferasy genetika metabolismus MeSH
- Arabidopsis genetika metabolismus MeSH
- cytokininy biosyntéza MeSH
- fylogeneze MeSH
- geneticky modifikované rostliny MeSH
- listy rostlin genetika metabolismus MeSH
- Populus genetika metabolismus MeSH
- regulátory růstu rostlin metabolismus MeSH
- rostlinné proteiny genetika metabolismus MeSH
- tandemová hmotnostní spektrometrie MeSH
- Publikační typ
- časopisecké články MeSH
To characterize the phytoextraction efficiency of two clones of willow trees (Salix x smithiana Willd., Salix rubens) and two clones of poplar trees (Populus nigra x maximowiczii, Populus nigra Wolterson) were planted in contaminated soil (0.4-2.0 mg Cd.kg(-1), 78-313 mg Zn.kg(-1), 21.3-118 mg Cu.kg(-1)). Field experiment was carried out in Czech Republic. The study investigated their ability to accumulate heavy metals (Cd, Zn, and Cu) in harvestable plant parts. The poplars produced higher amount of biomass than willows. Both Salix clones accumulated higher amount of Cd, Zn and Cu in their biomass (maximum 6.8 mg Cd.kg(-1), 909 mg Zn.kg(-1), and 17.7 mg Cu.kg(-1)) compared to Populus clones (maximum 2.06 mg Cd.kg(-1), 463 mg Zn.kg(-1), and 11.8 mg Cu.kg(-1)). There were no significant differences between clones of individual species. BCs for Cd and Zn were greater than 1 (the highest in willow leaves). BCs values of Cu were very low. These results indicate that Salix is more suitable plant for phytoextraction of Cd and Zn than Populus. The Cu phytoextraction potential of Salix and Populus trees was not confirmed in this experiment due to low soil availability of this element.
- MeSH
- biodegradace MeSH
- kadmium analýza metabolismus MeSH
- látky znečišťující půdu analýza metabolismus MeSH
- měď analýza metabolismus MeSH
- Populus chemie metabolismus MeSH
- regenerace a remediace životního prostředí přístrojové vybavení metody MeSH
- Salix chemie metabolismus MeSH
- stromy chemie metabolismus MeSH
- zinek analýza metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
- hodnotící studie MeSH
- práce podpořená grantem MeSH
We investigated feasibility of the Full-length complementary DNA OvereXpression (FOX) system as a mutagenesis approach in poplar, using developing xylem tissue. The main goal was to assess the overall mutation rate and if the system will increase instances of mutants affected in traits linked to the xylem tissue. Indeed, we found a high mutation rate of 17.7%, whereas 80% of all mutants were significantly affected in cellulose, lignin and/or hemicellulose. Cell wall biosynthesis is a major process occurring during xylem development. Enrichment of mutants affected in cell wall composition suggests that the tissue source for the FOX library influenced the occurrence of mutants affected in a trait linked to this tissue. Additionally, we found that FLcDNAs from mutants affected in cell wall composition were homologous to genes known to be involved in cell wall biosynthesis and most recovered FLcDNAs corresponded to genes whose native expression was highest in xylem. We characterized in detail a mutant line with increased diameter. The phenotype was caused by a poplar homolog of LONELY GUY 1 (LOG1), which encodes an enzyme in cytokinin biosynthesis and significantly increased xylem proliferation. The causative role of LOG1 in the observed phenotype was further reaffirmed by elevated cytokinin concentration in the mutant and recapitulation overexpression experiment wherein multiple independent lines phenocopied the original FOX mutant. Our experiments show that the FOX approach can be efficiently used for gene discovery and molecular interrogation of traits specific to woody perennial growth and development.
- MeSH
- buněčná stěna genetika metabolismus MeSH
- dřevo * genetika metabolismus MeSH
- genová knihovna MeSH
- lignin metabolismus MeSH
- mutační rychlost MeSH
- Populus * genetika metabolismus MeSH
- regulace genové exprese u rostlin genetika MeSH
- rostlinné proteiny genetika metabolismus MeSH
- xylém genetika metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Research Support, U.S. Gov't, Non-P.H.S. MeSH
Chelant-enhanced phytoextraction of heavy metals is an emerging technological approach for a non-destructive remediation of contaminated soils. The main objectives of this study were (i) to assess the extraction efficiency of two different synthetic chelating agents (ethylenediaminetetraacetic acid (EDTA) and ethylenediaminedisuccinic acid (EDDS)) for desorbing Pb from two contaminated agricultural soils originating from a mining and smelting district and (ii) to assess the phytoextraction efficiency of maize (Zea mays) and poplar (Populus sp.) after EDTA application. EDTA was more efficient than EDDS in desorbing and complexing Pb from both soils, removing as much as 60% of Pb. Maize exhibited better results than poplar when extracting Pb from the more acidic (pH approximately 4) and more contaminated (up to 1360 mg Pb kg(-1)) agricultural soil originating from the smelting area. On the other hand, poplars proved to be more efficient when grown on the near-neutral (pH approximately 6) and less contaminated (up to 200 mg Pb kg(-1)) agricultural soil originating from the mining area. Furthermore, the addition of EDTA led to a significant increase of Pb content especially in poplar leaves, proving a strong translocation rate within the poplar plants.
- MeSH
- biodegradace MeSH
- biomasa MeSH
- chelátory chemie MeSH
- EDTA chemie MeSH
- ethylendiaminy chemie MeSH
- financování organizované MeSH
- hornictví MeSH
- kukuřice setá chemie metabolismus MeSH
- látky znečišťující půdu izolace a purifikace MeSH
- olovo izolace a purifikace metabolismus MeSH
- Populus chemie metabolismus MeSH
- průmyslový odpad škodlivé účinky MeSH
- půda analýza MeSH
- sukcináty chemie MeSH
- zemědělství MeSH
Occurrence of stomata on both leaf surfaces (amphistomaty) promotes higher stomatal conductance and photosynthesis while simultaneously increasing exposure to potential disease agents in black cottonwood (Populus trichocarpa). A genome-wide association study (GWAS) with 2.2M single nucleotide polymorphisms generated through whole-genome sequencing found 280 loci associated with variation in adaxial stomatal traits, implicating genes regulating stomatal development and behavior. Strikingly, numerous loci regulating plant growth and response to biotic and abiotic stresses were also identified. The most significant locus was a poplar homologue of SPEECHLESS (PtSPCH1). Individuals possessing PtSPCH1 alleles associated with greater adaxial stomatal density originated primarily from environments with shorter growing seasons (e.g. northern latitudes, high elevations) or with less precipitation. PtSPCH1 was expressed in developing leaves but not developing stem xylem. In developing leaves, RNA sequencing showed patterns of coordinated expression between PtSPCH1 and other GWAS-identified genes. The breadth of our GWAS results suggests that the evolution of amphistomaty is part of a larger, complex response in plants. Suites of genes underpin this response, retrieved through genetic association to adaxial stomata, and show coordinated expression during development. We propose that the occurrence of amphistomaty in P. trichocarpa involves PtSPCH1 and reflects selection for supporting rapid growth over investment in immunity.
- MeSH
- alely MeSH
- celogenomová asociační studie MeSH
- druhová specificita MeSH
- fenotyp MeSH
- genotyp MeSH
- imunita rostlin genetika MeSH
- jednonukleotidový polymorfismus genetika MeSH
- kvantitativní znak dědičný MeSH
- podnebí MeSH
- Populus genetika růst a vývoj imunologie fyziologie MeSH
- průduchy rostlin genetika fyziologie MeSH
- regulace genové exprese u rostlin MeSH
- rostlinné geny MeSH
- rostlinné proteiny genetika metabolismus MeSH
- rozvržení tělního plánu * MeSH
- vývoj rostlin MeSH
- zeměpis MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
In the context of climate changes, clarifying the causes underlying tree phenotypic plasticity and adaptation is crucial. Studies suggest a role of epigenetic mechanisms in response to external stimuli, raising the question whether such processes can promote acclimation of trees exposed to adverse climate conditions. Recently, we revealed an environmental epigenetic footprint in the shoot apical meristem (SAM) which could partially be transmitted mitotically, for several months, up until the winter-dormant bud in field conditions. Here, we extended our previous analysis to the leaves of the same P. deltoides×P. nigra clones. We aimed at estimating the range of developmentally, genetically, and environmentally induced variations on DNA methylation. We showed that only the first leaves emerging from the SAM displayed variations of DNA methylation under changing water conditions. We also found that these variations are genotype- and pedoclimatic site-dependent. Altogether, our data raised questions and perspectives on the direct acquisition, the maintenance of environmentally induced DNA methylation changes, and their mitotic transmission from the SAM to the first emerging leaves.
Numerous studies demonstrated that endophytic microbes can promote plant growth and increase plant stress resistance. We aimed at isolating poplar endophytes able to increase their hosts' fitness both in nutrient-limited and polluted environments. To achieve this goal, endophytic bacteria and fungi were isolated from roots and leaves of hybrid poplars (Populus nigra × P. maximowiczii clone Max-4) on an unpolluted and a risk element-polluted site in the Czech Republic and subsequently screened by a number of in vitro tests. Bacterial communities at the unpolluted site were dominated by Gammaproteobacteria with Pseudomonas sp. as the prominent member of the class, followed by Bacilli with prevailing Bacillus sp., whereas Alphaproteobacteria, mostly Rhizobium sp., prevailed at the polluted site. The fungal endophytic community was dominated by Ascomycetes and highly distinct on both sites. Dothideomycetes, mostly Cladosporium, prevailed at the non-polluted site while unclassified Sordariomycetous fungi dominated at the polluted site. Species diversity of endophytes was higher at the unpolluted site. Many tested endophytic strains solubilized phosphate and produced siderophores, phytohormones, and antioxidants. Some strains also exhibited ACC-deaminase activity. Selected bacteria showed high tolerance and the ability to accumulate risk elements, making them promising candidates for use in inocula promoting biomass production and phytoremediation. Graphical Abstract ᅟ.
- MeSH
- antioxidancia metabolismus MeSH
- Bacteria klasifikace účinky léků izolace a purifikace metabolismus MeSH
- biodegradace MeSH
- biodiverzita MeSH
- biomasa MeSH
- endofyty klasifikace účinky léků izolace a purifikace metabolismus MeSH
- fosfáty metabolismus MeSH
- fylogeneze MeSH
- houby klasifikace účinky léků izolace a purifikace metabolismus MeSH
- kořeny rostlin mikrobiologie MeSH
- látky znečišťující životní prostředí toxicita MeSH
- listy rostlin mikrobiologie MeSH
- lyasy štěpící vazby C-C metabolismus MeSH
- mikrobiota účinky léků fyziologie MeSH
- Populus mikrobiologie MeSH
- půda chemie MeSH
- půdní mikrobiologie * MeSH
- regulátory růstu rostlin metabolismus MeSH
- siderofory metabolismus MeSH
- techniky in vitro MeSH
- tolerance léku MeSH
- vývoj rostlin * MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Česká republika MeSH
Phytomanagement of trace element-contaminated soils can reduce soil toxicity and restore soil ecological functions, including the soil gas exchange with the atmosphere. We studied the emission rate of the greenhouse gases (GHGs) CO2, CH4, and N2O; the potential CH4 oxidation; denitrification enzyme activity (DEA), and glucose mineralization of a Cu-contaminated soil amended with dolomitic limestone and compost, alone or in combination, after a 2-year phytomanagement with a mixed stand of Populus nigra, Salix viminalis, S. caprea, and Amorpha fruticosa. Soil microbial biomass and microbial community composition after analysis of the phospholipid fatty acids (PLFA) profile were determined. Phytomanagement significantly reduced Cu availability and soil toxicity, increased soil microbial biomass and glucose mineralization capacity, changed the composition of soil microbial communities, and increased the CO2 and N2O emission rates and DEA. Despite such increases, microbial communities were evolving toward less GHG emission per unit of microbial biomass than in untreated soils. Overall, the aided phytostabilization option would allow methanotrophic populations to establish in the remediated soils due to decreased soil toxicity and increased nutrient availability.
