Adaxial Dotaz Zobrazit nápovědu
The development of above-ground lateral organs is initiated at the peripheral zone of the shoot apical meristem (SAM). The coordination of cell fate determination and the maintenance of stem cells are achieved through a complex regulatory network comprised of transcription factors. Two AP2/ERF transcription factor family genes, ESR1/DRN and ESR2/DRNL/SOB/BOL, regulate cotyledon and flower formation and de novo organogenesis in tissue culture. However, their roles in post-embryonic lateral organ development remain elusive. In this study, we analyzed the genetic interactions among SAM-related genes, WUS and STM, two ESR genes, and one of the HD-ZIP III members, REV, whose protein product interacts with ESR1 in planta. We found that esr1 mutations substantially enhanced the wus and stm phenotypes, which bear a striking resemblance to those of the wus rev and stm rev double mutants, respectively. Aberrant adaxial-abaxial polarity is observed in wus esr1 at relatively low penetrance. On the contrary, the esr2 mutation partially suppressed stm phenotypes in the later vegetative phase. Such complex genetic interactions appear to be attributed to the distinct expression pattern of two ESR genes because the ESR1 promoter-driving ESR2 is capable of rescuing phenotypes caused by the esr1 mutation. Our results pose the unique genetic relevance of ESR1 and the SAM-related gene interactions in the development of rosette leaves.
- Klíčová slova
- Arabidopsis thaliana, ENHANCER OF SHOOT REGENERATION 1, REVOLTA, SHOOTMERISTEMLESS, WUSCHEL, adaxial–abaxial polarity, lateral organ, shoot apical meristem,
- MeSH
- Arabidopsis genetika růst a vývoj MeSH
- fenotyp MeSH
- homeodoménové proteiny genetika MeSH
- listy rostlin genetika růst a vývoj MeSH
- meristém genetika růst a vývoj MeSH
- mutace MeSH
- organogeneze rostlin genetika MeSH
- proteiny huseníčku genetika MeSH
- regulace genové exprese u rostlin * MeSH
- rostlinné geny * MeSH
- transkripční faktory genetika MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- ESR1 protein, Arabidopsis MeSH Prohlížeč
- homeodoménové proteiny MeSH
- proteiny huseníčku MeSH
- transkripční faktory MeSH
- WUSCHEL protein, Arabidopsis MeSH Prohlížeč
Adaxial, abaxial phylloplane (leaf), and spermoplane (seed) are proximal yet contrasting habitats for a microbiota that needs to be adequately explored. Here, we proposed novel methods to decipher the adaxial/abaxial-phylloplane and spermoplane-microbiomes. Comparison of 22 meta barcoded-NGS datasets (size of total data set-1980.48 Mb) enabled us to fine-map the microbiome of the rice foliar niche, which encompasses the lower, middle, top leaf as well panicle. Here, the total- and the cultivable-microbiome profiling revealed 157 genera representing ten phyla and 87 genera from 4 bacterial phyla, respectively, with a predominance of Proteobacteria and Actinobacteria. Interestingly, more bacterial communities (124-genera) preferred the abaxial than the adaxial phylloplane (104-genera) and spermoplane (67-genera) for colonization. The microbiome profiles were nearly identical on the aromatic (125-genera) and non-aromatic rice (116-genera) with high representation of Pantoea, Methylobacterium, Curtobacterium, Sphingopyxis, and Microbacterium. The culturomics investigation confirmed the abundance of Pantoea, Chryseobacterium, Pseudomonas, Acinetobacter, Sphingobacterium, and Exiguobacterium. One hundred bacterial isolates characterized and identified by polyphasic-taxonomic tools revealed the dominance of Acinetobacter, Chryseobacterium, Enterobacter, Massilia, Pantoea, Pseudomonas, and Stenotrophomonas on adaxial/abaxial-phylloplane and spermoplane. The study culminated in identifying hitherto unexplored bacterial communities on the adaxial/abaxial phylloplane and spermoplane of rice that can be harnessed for microbiome-assisted rice cultivation in the future.
- Klíčová slova
- Abaxial, Adaxial, Metabarcoding, Microbiome, Phylloplane, Rice, Spermoplane,
- MeSH
- genotyp MeSH
- listy rostlin mikrobiologie MeSH
- mikrobiota * MeSH
- rýže (rod) * MeSH
- Sphingomonadaceae * MeSH
- Publikační typ
- časopisecké články MeSH
BACKGROUND AND AIMS: The benefits and costs of amphistomy (AS) vs. hypostomy (HS) are not fully understood. Here, we quantify benefits of access of CO2 through stomata on the upper (adaxial) leaf surface, using 13C abundance in the adaxial and abaxial epicuticular wax. Additionally, a relationship between the distribution of stomata and epicuticular wax on the opposite leaf sides is studied. METHODS: We suggest that the 13C content of long-chain aliphatic compounds of cuticular wax records the leaf internal CO2 concentration in chloroplasts adjacent to the adaxial and abaxial epidermes. This unique property stems from: (1) wax synthesis being located exclusively in epidermal cells; and (2) ongoing wax renewal over the whole leaf lifespan. Compound-specific and bulk wax 13C abundance (δ) was related to amphistomy level (ASL; as a fraction of adaxial in all stomata) of four AS and five HS species grown under various levels of irradiance. The isotopic polarity of epicuticular wax, i.e. the difference in abaxial and adaxial δ (δab - δad), was used to calculate the leaf dorsiventral CO2 gradient. Leaf-side-specific epicuticular wax deposition (amphiwaxy level) was estimated and related to ASL. KEY RESULTS: In HS species, the CO2 concentration in the adaxial epidermis was lower than in the abaxial one, independently of light conditions. In AS leaves grown in high-light and low-light conditions, the isotopic polarity and CO2 gradient varied in parallel with ASL. The AS leaves grown in high-light conditions increased ASL compared with low light, and δab - δad approached near-zero values. Changes in ASL occurred concomitantly with changes in amphiwaxy level. CONCLUSIONS: Leaf wax isotopic polarity is a newly identified leaf trait, distinguishing between hypo- and amphistomatous species and indicating that increased ASL in sun-exposed AS leaves reduces the CO2 gradient across the leaf mesophyll. Stomata and epicuticular wax deposition follow similar leaf-side patterning.
- Klíčová slova
- Brassica oleracea, Capsicum annuum, Amphistomy, abaxial, adaxial, carbon isotope, cuticle, epicuticular wax, leaf internal CO2 concentration, light, photosynthesis, stomata,
- MeSH
- epidermis rostlin * metabolismus MeSH
- fotosyntéza MeSH
- izotopy uhlíku * analýza MeSH
- listy rostlin * metabolismus MeSH
- oxid uhličitý * metabolismus MeSH
- průduchy rostlin * fyziologie MeSH
- vosky * metabolismus chemie MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- Carbon-13 MeSH Prohlížeč
- izotopy uhlíku * MeSH
- oxid uhličitý * MeSH
- vosky * MeSH
Element content and expression of genes of interest on single cell types, such as stomata, provide valuable insights into their specific physiology, improving our understanding of leaf gas exchange regulation. We investigated how far differences in stomatal conductance (gs ) can be ascribed to changes in guard cells functioning in amphistomateous leaves. gs was measured during the day on both leaf sides, on well-watered and drought-stressed trees (two Populus euramericana Moench and two Populus nigra L. genotypes). In parallel, guard cells were dissected for element content and gene expressions analyses. Both were strongly arranged according to genotype, and drought had the lowest impact overall. Normalizing the data by genotype highlighted a structure on the basis of leaf sides and time of day both for element content and gene expression. Guard cells magnesium, phosphorus, and chlorine were the most abundant on the abaxial side in the morning, where gs was at the highest. In contrast, genes encoding H+ -ATPase and aquaporins were usually more abundant in the afternoon, whereas genes encoding Ca2+ -vacuolar antiporters, K+ channels, and ABA-related genes were in general more abundant on the adaxial side. Our work highlights the unique physiology of each leaf side and their analogous rhythmicity through the day.
- Klíčová slova
- Populus, abaxial and adaxial surfaces, droughts, elements, gene expression, plant stomata, stomatal conductance,
- MeSH
- genotyp MeSH
- komplementární DNA genetika izolace a purifikace MeSH
- listy rostlin genetika metabolismus MeSH
- mikroanalýza elektronovou sondou MeSH
- období sucha MeSH
- Populus klasifikace genetika metabolismus MeSH
- protonové ATPasy genetika metabolismus MeSH
- průduchy rostlin genetika metabolismus MeSH
- regulace genové exprese u rostlin MeSH
- RNA rostlin genetika izolace a purifikace MeSH
- rostlinné proteiny genetika metabolismus MeSH
- stromy genetika metabolismus MeSH
- transpirace rostlin fyziologie MeSH
- voda fyziologie MeSH
- vývoj rostlin MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- komplementární DNA MeSH
- protonové ATPasy MeSH
- RNA rostlin MeSH
- rostlinné proteiny MeSH
- voda MeSH
Cuticular water permeabilities of adaxial and abaxial leaf surfaces and their dependence on relative air humidity (RH) applied in long-term and short-term regimes have been analysed for Hedera helix, native in a temperate climate, and Zamioculcas zamiifolia, native in subtropical regions. The water permeability of cuticular membranes (CM) isolated from the adaxial (astomatous) and abaxial (stomatous) leaf sides was measured using a method which allowed the separation of water diffusion through the remnants of the original stomatal pores from water diffusion through the solid cuticle. The long-term effects of low (20-40%) or high (60-80%) RH applied during plant growth and leaf ontogeny ('growth RH') and the short-term effects of applying 2% or 100% RH while measuring permeability ('measurement RH') were investigated. With both species, water permeability of the solid stomatous CM was significantly higher than the permeability of the astomatous CM. Adaxial cuticles of plants grown in humid air were more permeable to water than those from dry air. The adaxial CM of the drought-tolerant H. helix was more permeable and more sensitive to growth RH than the adaxial CM of Z. zamiifolia, a species avoiding water stress. However, permeability of the solid abaxial CM was similar in both species and independent of growth RH. The lack of a humidity response in the abaxial CM is attributed to a higher degree of cuticular hydration resulting from stomatal transpiration. The ecophysiological significance of higher permeability of the solid stomatous CM compared to the astomatous CM is discussed.
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.
- Klíčová slova
- GWAS, Populus trichocarpa, amphistomaty, association genetics, immunity, stomata, trait trade-offs,
- 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
- Názvy látek
- rostlinné proteiny MeSH
In July 2021, leaves and shoot tops of the common hazel (Corylus avellana L.), with a whitish coating, were found in the Czech Republic (southern Moravia region). The infected hazel bushes were found along a road in a deciduous forest and in an urban garden. In most European countries, Phyllactinia guttata is found on the abaxial surface of the leaves in the form of a continuous whitish to light grey mycelium, possibly with large black chasmothecia. In our case, the mycelium was present on both sides of the leaves, but the symptoms and the incidence were much stronger on the adaxial side. The first symptoms usually appeared on the adaxial side of the leaves as small white radially expanding patches of mycelium. In the final stage, the spots merged and covered a substantial part of the leaf blade (50-85 % on the adaxial side, 5-25 % on the abaxial side). When the abaxial side of the leaves was infected, chlorotic spots were evident on the adaxial side. The spots of powdery mildew were small (3-15 mm), whitish, rounded to irregular, effuse eventually becoming confluent, and occurred primarily on the adaxial side of the leaves. Conidiophores (30-53×4-6 µm) grew on the amphigenic mycelium, were erect, consisted of 1-3 cells, i.e. cylindrical foot cell and followed 1-2 cells, from which hyaline ellipsoid to doliform-limoniform conidia (17-34 ×15-21) (n = 50) were individually detached. Single or in groups dark brown chasmothecia (77-116 µm in diameter) had up to hyaline 8-15 aseptate straight appendages (50-102 µm) with multiple (3-5×) dichotomously branched apexes and recurved tips. Chasmothecia contained 3-6 asci (42-62 × 34-55 µm) with 4-8 obovoid to broadly ellipsoidal hyaline ascospores (14-22 × 75 µm). Based on morphological characters, the powdery mildew was identified as Erysiphe corylacearum (2). Morphological identification was confirmed by molecular analysis of samples. DNA was extracted from symptomatic leaves tissue using the DNeasy Plant Mini Kit, (Quiagen, Hilden, Germany) and the rDNA internal transcribed spacer region of 2 isolates was amplified using primers PMITS1 and PMITS2 (Cunnington et al. 2003) and sequenced. BLAST analysis of our 720bp fragments (both identical and represented by GenBank accession no. OR432526) showed 100% sequence identity to ITS rDNA sequences of E. corylacearum other countries of Central Europe for example from Austria (MW031866), Italy (MW045428), Hungary (OQ411007), Germany (OP554268) or Slovakia (MT176105). Pathogenicity was verified on two-year-old plants of Corylus avellana. Healthy leaves were artificially infected by dusting conidia from infected leaves. Inoculated plants were incubated under controlled conditions (21-23 °C, 70-80 % relative humidity). Characteristic symptoms of powdery mildew appeared on the adaxial side of the leaves 9-12 days after inoculation. Control plants treated with distilled water remained symptomless. Powdery mildew isolated from inoculated leaves was morphologically identical to isolates from naturally infected leaves. The first record of E. corylacearum in Europe on cultivated hazelnut species was reported by Sezer et al. (2017) in Turkey in 2013. Within a few years, the E. corylacearum spread and was recorded on various species of Corylus in other European countries (for example Mezzalama et al., 2020; Rosati et al., 2021; Beenken et al., 2022; Boneva et al., 2023), East Asia (Arzanlou et al., 2018) and the USA (Meparishvili 2019). To our knowledge, this is the first report of Erysiphe corylacearum in the Czech Republic.
- Klíčová slova
- Corylus avellana, Czech Republic, Erysiphe corylacearum, hazelnut powdery mildew,
- Publikační typ
- časopisecké články MeSH
Natural SiO2 nanoparticles (SiO2-NPs) are widely distributed in the environment, and at the same time, synthetic SiO2-NP may be applied in agriculture. Evaluations of physiological responses to SiO2-NPs treatment of plants are controversial. They are often performed at adaxial leaf sides whereas NPs permeate leaf tissues through stomata located at the abaxial leaf side in the majority of bifacial plants. We measured coefficients of the functional dorsoventral asymmetry of NPs-stressed Chelidonium majus leaves, S, by values of the CO2 assimilation rate (SP N), dark respiration (SR), maximal and operating quantum yields of photosystem II (SFv/Fm, SFv'/Fm'; using PAM-fluorometry), and oxygen coefficients of photosynthesis (SΨO2; using photoacoustics). The results indicated that SP N and SΨO2 were significantly influenced by SiO2-NPs treatment, since P N and ΨO2 were declining more markedly when the light was directed to the abaxial side of leaves compared to the adaxial side. Overall, SiO2-NPs-induced stress increased 'anoxygenity' of photosynthesis.
- Klíčová slova
- CO2 assimilation kinetics, cyclic electron transport around PSII, energy storage, photobaric signal, photothermal signal, transpiration kinetics,
- Publikační typ
- časopisecké články MeSH
BACKGROUND: The southern African Oxalis radiation is extremely morphologically variable. Despite recent progress in the phylogenetics of the genus, there are few morphological synapomorphies supporting DNA-based clades. Leaflet anatomy can provide an understudied and potentially valuable source of information on the evolutionary history and systematics of this lineage. Fifty-nine leaflet anatomical traits of 109 southern African Oxalis species were assessed in search of phylogenetically significant characters that delineate clades. RESULTS: A combination of 6 leaflet anatomical traits (stomatal position, adaxial epidermal cells, abaxial epidermal cells, mesophyll, sheath around vascular tissue, degree of leaflet conduplication) clearly support various clades defined by previous DNA-based phylogenetic work. Other, mostly continuous leaflet anatomical traits were highly variable and showed less phylogenetic pattern. CONCLUSIONS: Major and unexpected findings include the transition from ancestral hypostomatic leaflets to adaxially-located stomata in the vast majority of southern African Oxalis, the loss of semi-swollen AB epidermal cells and the gain of swollen adaxial and abaxial epidermal cells in selected clades, and multiple changes from ancestral bifacial mesophyll to isobilateral or homogenous mesophyll types. The information gathered in this study will aid in the taxonomic revision of this speciose member of the Greater Cape Floristic Region and provide a basis for future hypotheses regarding its radiation.
- Klíčová slova
- Ancestral state reconstruction, Epistomaty, Leaf anatomy, Oxalis, Phylogenetics, Stomatal position,
- MeSH
- biologická evoluce MeSH
- cévní svazky rostlin cytologie MeSH
- duplikace genu MeSH
- fenotyp MeSH
- fylogeneze * MeSH
- kvantitativní znak dědičný MeSH
- listy rostlin anatomie a histologie cytologie genetika MeSH
- mezofylové buňky cytologie MeSH
- Oxalidaceae anatomie a histologie genetika MeSH
- průduchy rostlin cytologie MeSH
- trichomy cytologie MeSH
- Publikační typ
- časopisecké články MeSH
We suggest a new technique for estimating the relative drawdown of CO2 concentration (c) in the intercellular air space (IAS) across hypostomatous leaves (expressed as the ratio cd/cb, where the indexes d and b denote the adaxial and abaxial edges, respectively, of IAS), based on the carbon isotope composition (δ13C) of leaf cuticular membranes (CMs), cuticular waxes (WXs) or epicuticular waxes (EWXs) isolated from opposite leaf sides. The relative drawdown in the intracellular liquid phase (i.e., the ratio cc/cbd, where cc and cbd stand for mean CO2 concentrations in chloroplasts and in the IAS), the fraction of intercellular resistance in the total mesophyll resistance (rIAS/rm), leaf thickness, and leaf mass per area (LMA) were also assessed. We show in a conceptual model that the upper (adaxial) side of a hypostomatous leaf should be enriched in 13C compared to the lower (abaxial) side. CM, WX, and/or EWX isolated from 40 hypostomatous C3 species were 13C depleted relative to bulk leaf tissue by 2.01-2.85‰. The difference in δ13C between the abaxial and adaxial leaf sides (δ13CAB - 13CAD, Δb-d), ranged from - 2.22 to + 0.71‰ (- 0.09 ± 0.54‰, mean ± SD) in CM and from - 7.95 to 0.89‰ (- 1.17 ± 1.40‰) in WX. In contrast, two tested amphistomatous species showed no significant Δb-d difference in WX. Δb-d correlated negatively with LMA and leaf thickness of hypostomatous leaves, which indicates that the mesophyll air space imposes a non-negligible resistance to CO2 diffusion. δ13C of EWX and 30-C aldehyde in WX reveal a stronger CO2 drawdown than bulk WX or CM. Mean values of cd/cb and cc/cbd were 0.90 ± 0.12 and 0.66 ± 0.11, respectively, across 14 investigated species in which wax was isolated and analyzed. The diffusion resistance of IAS contributed 20 ± 14% to total mesophyll resistance and reflects species-specific and environmentally-induced differences in leaf functional anatomy.
- Klíčová slova
- CO2 diffusion, Carbon isotope discrimination, Cuticle, Leaf mesophyll, Leaf traits, Mesophyll conductance, Waxes,
- MeSH
- biologické modely MeSH
- extracelulární prostor metabolismus MeSH
- izotopy uhlíku metabolismus MeSH
- listy rostlin anatomie a histologie růst a vývoj metabolismus MeSH
- mezofylové buňky metabolismus MeSH
- nadmořská výška MeSH
- oxid uhličitý metabolismus MeSH
- vosky metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- izotopy uhlíku MeSH
- oxid uhličitý MeSH
- vosky MeSH
