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A study was conducted to further develop our understanding of antimony (Sb) uptake in plants. Unlike other metal(loid)s, such as silicon (Si), the mechanisms of Sb uptake are not well understood. However, SbIII is thought to enter the cell via aquaglyceroporins. We investigated if the channel protein Lsi1, which aids in Si uptake, also plays a role in Sb uptake. Seedlings of WT sorghum, with normal silicon accumulation, and its mutant (sblsi1), with low silicon accumulation, were grown in Hoagland solution for 22 days in the growth chamber under controlled conditions. Control, Sb (10 mg Sb L-1), Si (1mM) and Sb + Si (10 mg Sb L-1 + 1 mM Si) were the treatments. After 22 days, root and shoot biomass, the concentration of elements in root and shoot tissues, lipid peroxidation and ascorbate levels, and relative expression of Lsi1 were determined. When mutant plants were exposed to Sb, they showed almost no toxicity symptoms compared to WT plants, indicating that Sb was not toxic to mutant plants. On the other hand, WT plants had decreased root and shoot biomass, increased MDA content and increased Sb uptake compared to mutant plants. In the presence of Sb, we also found that SbLsi1 was downregulated in the roots of WT plants. The results of this experiment support the role of Lsi1 in Sb uptake in sorghum plants.
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Calpains are modulatory proteases that modify diverse cellular substrates and play essential roles in eukaryots. The best studied are animal cytosolic calpains. Here, we focus on enigmatic membrane-anchored calpains, their structural and functional features as well as phylogenetic distribution. Based on domain composition, we identified four types of membrane-anchored calpains. Type 1 and 2 show broad phylogenetic distribution among unicellular protists and streptophytes suggesting their ancient evolutionary origin. Type 3 and 4 diversified early and are present in brown algae and oomycetes. The plant DEK1 protein is the only representative of membrane-anchored calpains that has been functionally studied. Here, we present up to date knowledge about its structural features, putative regulation, posttranslational modifications, and biological role. Finally, we discuss potential model organisms and available tools for functional studies of membrane-anchored calpains with yet unknown biological role. Mechanistic understanding of membrane-anchored calpains may provide important insights into fundamental principles of cell polarization, cell fate control, and morphogenesis beyond plants.
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General volatile anaesthetics (GVA) inhibit electrical signal propagation in animal neurons. Although plants do not have neurons, they generate and propagate electrical signals systemically from a local damaged leaf to neighbouring leaves. This systemic electrical signal propagation is mediated by ligand-gated glutamate receptor-like (GLR) channels. Here, we investigated the effect of GVA diethyl ether on the systemic electrical and further downstream responses in Arabidopsis thaliana. We monitored electrical signals, cytoplasmic Ca2+ level ([Ca2+]cyt), ultra-weak photon emission, amino acid contents, phytohormone response as well as gene expression in response to heat wounding during diethyl ether anaesthesia. We found complete suppression of electrical and [Ca2+]cyt signal propagation from damaged leaf to neighbouring systemic leaves upon diethyl ether treatment. Concomitantly, jasmonates (JAs) did not accumulate and expression of JA-responsive genes (AOS, OPR3, JAZ10) was not detected in systemic leaves. However local damaged leaves still showed increased [Ca2+]cyt and accumulated high level of JAs and JA-inducible transcripts. An exogenously added GLR ligand, L-glutamate, was not able to trigger Ca2+ wave in etherized plants indicating that GLRs are targeted by diethyl ether, but not specifically. The fact that GVA inhibit electrical signal propagation not only in animals but also in plants is intriguing. However, the cellular response is completely blocked only in systemic leaves; the local damaged leaf still senses damaging stimuli.
Sujet(s)
Anesthésiques , Protéines d'Arabidopsis , Arabidopsis , Animaux , Arabidopsis/génétique , Arabidopsis/métabolisme , Protéines d'Arabidopsis/génétique , Protéines d'Arabidopsis/métabolisme , Cyclopentanes/pharmacologie , Oxyde de diéthyle , Régulation de l'expression des gènes végétaux , Oxylipines/pharmacologie , Feuilles de plante/métabolismeRÉSUMÉ
In the last decades, the concentration of atmospheric CO2 and the average temperature have been increasing, and this trend is expected to become more severe in the near future. Additionally, environmental stresses including drought, salinity, UV-radiation, heavy metals, and toxic elements exposure represent a threat for ecosystems and agriculture. Climate and environmental changes negatively affect plant growth, biomass and yield production, and also enhance plant susceptibility to pests and diseases. Silicon (Si), as a beneficial element for plants, is involved in plant tolerance and/or resistance to various abiotic and biotic stresses. The beneficial role of Si has been shown in various plant species and its accumulation relies on the root's uptake capacity. However, Si uptake in plants depends on many biogeochemical factors that may be substantially altered in the future, affecting its functional role in plant protection. At present, it is not clear whether Si accumulation in plants will be positively or negatively affected by changing climate and environmental conditions. In this review, we focused on Si interaction with the most important factors of global change and environmental hazards in plants, discussing the potential role of its application as an alleviation strategy for climate and environmental hazards based on current knowledge.
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Métalloïdes , Silicium , Changement climatique , Écosystème , PlantesRÉSUMÉ
Zea mays L. is one of the most produced crops, and there are still parts of the world where maize is the basic staple food. To improve agriculture, mankind always looks for new, better methods of growing crops, especially in the current changing climatic conditions. Cold atmospheric pressure plasma (CAPP) has already showed its potential to enhance the culturing of crops, but it still needs more research for safe implementation into agriculture. In this work, it was shown that short CAPP treatment of maize grains had a positive effect on the vitality of grains and young seedlings, which may be connected to stimulation of antioxidant and lytic enzyme activities by short CAPP treatment. However, the prolonged treatment had a negative impact on the germination, growth, and production indexes. CAPP treatment caused the increased expression of genes for heat shock proteins HSP101 and HSP70 in the first two days after sowing. Using comet assay it was observed that shorter treatment times (30-120 s) did not cause DNA damage. Surface diagnostics of plasma-treated grains showed that plasma increases the hydrophilicity of the surface but does not damage the chemical bonds on the surface.
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Grains comestibles/croissance et développement , Protéines du choc thermique HSP70/métabolisme , Peptide hydrolases/métabolisme , Protéines végétales/métabolisme , Gaz plasmas/pharmacologie , Facteurs de transcription/métabolisme , Zea mays/croissance et développement , Pression atmosphériqueRÉSUMÉ
To evaluate the multiplicity of reactions to toxic metalloid arsenic (As) with specific emphasis on the role of plant peroxidases, a model plant Nicotiana benthamiana was cultivated in in vitro conditions at various doses of As (applied as As5+ up to 80 µM). After 28-day cultivation, several physiological characteristics such as plant growth, photosynthetic pigment concentration, As concentration, peroxidase (POX) expression levels, and POX activity were evaluated. A newly sequenced gene for POX has been identified, that belongs to the Class III plant extracellular peroxidases, and its relationship to the genus Solanum as the most relative species has been confirmed. In the control and selected As treatments (20As, 50As, and 80As), newly identified POX expression and POX activity were continuously detected during the whole cultivation period. The plant reactions to As stress were distinguished into three groups: low As, moderate As, and high As. A tight relationship was found between the photosynthetic pigments and POX expression. Accumulation of As in roots and shoots showed correlations with POX activities. The results showed that the diversity of reactions depends on As dose and time exposure and indicate an interface of peroxidase functional role with other physiological processes in plants suffering from As toxicity.
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Arsenic , Myeloperoxidase , Arsenic/toxicité , Catalase/métabolisme , Stress oxydatif , Myeloperoxidase/génétique , Myeloperoxidase/métabolisme , Peroxidases/génétique , Peroxidases/métabolisme , Racines de plante/métabolisme , Nicotiana/métabolismeSujet(s)
Bryopsida/métabolisme , Noyau de la cellule/métabolisme , DEAD-box RNA helicases/métabolisme , Cellules germinales de plante/métabolisme , Bryopsida/génétique , DEAD-box RNA helicases/génétique , Régulation de l'expression des gènes végétaux , Protéines végétales/génétique , Protéines végétales/métabolisme , RNA helicases , Amidon/métabolismeRÉSUMÉ
The carnivorous pitcher plants of the genus Nepenthes usually attract, capture and digest arthropod prey to obtain mineral nutrients. But few members of the genus have evolved specialized nutrient sequestration strategies to acquire nitrogen from the faeces and urine of mutualistic mammals, which they attract. Because the plants obtain significant amounts of nitrogen in a more available form, we hypothesized that they have relaxed the production of digestive enzymes. If so, species that digest mammal faeces should show fewer digestive enzymes than closely related species that rely on arthropods. We tested this hypothesis by comparing digestive enzymes in 1) Nepenthes hemsleyana, whose pitchers serve as roosts for the mutualistic woolly bat Kerivoula hardwickii, which also defecate inside the pitchers, and 2) the close relative Nepenthes rafflesiana, a typical arthropod capturing species. To investigate the dynamics of aspartic proteases (nepenthesin I and II) and type III and IV chitinases in both species, we conducted qPCR, western blotting, mass spectrometry, and enzyme activity measurements. We found that mRNA in pitcher tissue and enzyme abundance in the digestive fluid is upregulated in both species in response to faeces and insect feeding. Contrary to our initial hypothesis, the final nepenthesin proteolytic activity in the digestive fluid is higher in response to faeces addition than to insect prey irrespective of Nepenthes species. This indicates that faeces can mimic arthropod prey triggering the production of digestive enzymes and N. hemsleyana retained capacity for production of them.
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Plante carnivore , Magnoliopsida , Animaux , Azote , Nutriments , Composés chimiques organiques , SymbioseRÉSUMÉ
MAIN CONCLUSION: Silicon inhibits the growth of Alternaria alternata into sorghum root cells by maintaining their integrity through stimulating biochemical defense reactions rather than by silica-based physical barrier creation. Although the ameliorating effect of silicon (Si) on plant resistance against fungal pathogens has been proven, the mechanism of its action needs to be better understood on a cellular level. The present study explores the effect of Si application in sorghum roots infected with fungus Alternaria alternata under controlled in vitro conditions. Detailed anatomical and cytological observations by both fluorescent and electron microscopy revealed that Si supplementation results in the inhibition of fungal hyphae growth into the protoplast of root cells. An approach of environmental scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy enabling spatial detection of Si even at low concentrations showed that there is no continual solid layer of silica in the root cell walls of the rhizodermis, mesodermis and exodermis physically blocking the fungal growth into the protoplasts. Additionally, biochemical evidence suggests that Si speeds up the onset of activities of phenylpropanoid pathway enzymes phenylalanine ammonia lyase, peroxidases and polyphenol oxidases involved in phenolic compounds production and deposition to plant cell walls. In conclusion, Si alleviates the negative impact of A. alternata infection by limiting hyphae penetration through sorghum root cell walls into protoplasts, thus maintaining their structural and functional integrity. This might occur by triggering plant biochemical defense responses rather than by creating compact Si layer deposits.
Sujet(s)
Alternaria , Racines de plante , Silicium , Sorghum , Alternaria/effets des médicaments et des substances chimiques , Phenylalanine ammonia-lyase , Maladies des plantes/microbiologie , Racines de plante/effets des médicaments et des substances chimiques , Racines de plante/enzymologie , Racines de plante/microbiologie , Silicium/pharmacologie , Sorghum/effets des médicaments et des substances chimiques , Sorghum/enzymologie , Sorghum/microbiologieRÉSUMÉ
INTRODUCTION: In contrast to obesity, little is known about the human lean phenotype associated with gut microbiota composition. OBJECTIVE: We aimed to investigate whether the bacterial composition of lean athletes with a positive energy balance differs from the equal-calorie food group. METHODS: Twenty-four male participants were included in this cross-sectional study: lean athletes with a positive energy balance (LA, n 12) and control group athletes (CTRLs, n 12). Nutritional data, resting and total energy expenditure, and body composition were determined. DNA was extracted from stool samples and subjected to 16S rRNA gene analysis. RESULTS: We found 7 differentially abundant bacterial taxa between the LA and CTRL groups. Of those, 5 were significantly less abundant and 2 were enriched in the LA group. The following categories significantly associated with the community structure were identified: body fat parameters, BMI, energy intake and expenditure, oxygen consumption, and respiratory exchange ratio. CONCLUSIONS: Although we are far from a detailed interpretation of lean human body maintenance, the primary findings of our study suggest that gut microbial composition may be a factor influencing the regulation of weight gain in lean athletes with a positive energy balance.
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Métabolisme énergétique/physiologie , Microbiome gastro-intestinal/physiologie , Poids idéal/physiologie , Sports/physiologie , Maigreur/microbiologie , Adulte , Athlètes , Composition corporelle , Indice de masse corporelle , Études transversales , Enquêtes sur le régime alimentaire , Fèces/microbiologie , Microbiome gastro-intestinal/génétique , Humains , Mâle , ARN ribosomique 16S/analyse , Repos/physiologie , Maigreur/métabolisme , Jeune adulteRÉSUMÉ
Silicon (Si), although not considered as an essential element for plants in general, can ameliorate the phytotoxicity induced by excess metal(loid)s whether non-essential (e.g. Cd, Pb, Cr, Al, As, and Sb) or essential (e.g. Cu, Ni, and Zn). The Si-enhanced resistance allowing plants to cope with this type of abiotic stress has been developed at multiple levels in plants. Restriction of root uptake and immobilization of metal(loid)s in the rhizosphere by Si is probably one of the first defence mechanism. Further, retention of elements in the root apoplasm might enhance the resistance and vigour of plants. At the cellular level, the formation of insoluble complexes between Si and metal(loid)s and their storage within cell walls help plants to decrease available element concentration and restrict symplasmic uptake. Moreover, Si influences the oxidative status of plants by modifying the activity of various antioxidants, improves membrane stability, and acts on gene expression, although its exact role in these processes is still not well understood. This review focuses on all currently known plant-based mechanisms related to Si supply and involved in amelioration of stress caused by excess metal(loid)s.
Sujet(s)
Silicium , Polluants du sol , Transport biologique , Métaux , Plantes , RhizosphèreRÉSUMÉ
Cucumber mosaic virus (CMV), with extremely broad host range including both monocots and dicots around the world, belongs to most important viral crop threats. Either natural or genetically constructed sources of resistance are being intensively investigated; for this purpose, exhaustive knowledge of molecular virus-host interaction during compatible and incompatible infection is required. New technologies and computer-based "omics" on various levels contribute markedly to this topic. In this work, two cucumber cultivars with different response to CMV challenge were tested, i.e., sensitive cv. Vanda and resistant cv. Heliana. The transcriptomes were prepared from both cultivars at 18 days after CMV or mock inoculation. Subsequently, four independent comparative analyses of obtained data were performed, viz. mock- and CMV-inoculated samples within each cultivar, samples from mock-inoculated cultivars to each other and samples from virus-inoculated cultivars to each other. A detailed picture of CMV-influenced genes, as well as constitutive differences in cultivar-specific gene expression was obtained. The compatible CMV infection of cv. Vanda caused downregulation of genes involved in photosynthesis, and induction of genes connected with protein production and modification, as well as components of signaling pathways. CMV challenge caused practically no change in the transcription profile of the cv. Heliana. The main differences between constitutive transcription activity of the two cultivars relied in the expression of genes responsible for methylation, phosphorylation, cell wall organization and carbohydrate metabolism (prevailing in cv. Heliana), or chromosome condensation and glucan biosynthesis (prevailing in cv. Vanda). Involvement of several genes in the resistant cucumber phenotype was predicted; this can be after biological confirmation potentially applied in breeding programs for virus-resistant crops.
RÉSUMÉ
Silicon (Si) is not considered an essential element, however, its tissue concentration can exceed that of many essential elements in several evolutionary distant plant species. Roots take up Si using Si transporters and then translocate it to aboveground organs. In some plant species, root tissues are also places where a high accumulation of Si can be found. Three basic modes of Si deposition in roots have been identified so far: (1) impregnation of endodermal cell walls (e.g., in cereals, such as Triticum (wheat)); (2) formation of Si-aggregates associated with endodermal cell walls (in the Andropogoneae family, which includes Sorghum and Saccharum (sugarcane)); (3) formation of Si aggregates in "stegmata" cells, which form a sheath around sclerenchyma fibers e.g., in some palm species (Phoenix (date palm)). In addition to these three major and most studied modes of Si deposition in roots, there are also less-known locations, such as deposits in xylem cells and intercellular deposits. In our research, the ontogenesis of individual root cells that accumulate Si is discussed. The documented and expected roles of Si deposition in the root is outlined mostly as a reaction of plants to abiotic and biotic stresses.
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BACKGROUND AND AIMS: General anaesthetics are compounds that induce loss of responsiveness to environmental stimuli in animals and humans. The primary site of action of general anaesthetics is the nervous system, where anaesthetics inhibit neuronal transmission. Although plants do not have neurons, they generate electrical signals in response to biotic and abiotic stresses. Here, we investigated the effect of the general volatile anaesthetic diethyl ether on the ability to sense potential prey or herbivore attacks in the carnivorous plant Venus flytrap (Dionaea muscipula). METHODS: We monitored trap movement, electrical signalling, phytohormone accumulation and gene expression in response to the mechanical stimulation of trigger hairs and wounding under diethyl ether treatment. KEY RESULTS: Diethyl ether completely inhibited the generation of action potentials and trap closing reactions, which were easily and rapidly restored when the anaesthetic was removed. Diethyl ether also inhibited the later response: jasmonic acid (JA) accumulation and expression of JA-responsive genes (cysteine protease dionain and type I chitinase). However, external application of JA bypassed the inhibited action potentials and restored gene expression under diethyl ether anaesthesia, indicating that downstream reactions from JA are not inhibited. CONCLUSIONS: The Venus flytrap cannot sense prey or a herbivore attack under diethyl ether treatment caused by inhibited action potentials, and the JA signalling pathway as a consequence.
Sujet(s)
Anesthésie , Droseraceae , Animaux , Cyclopentanes , Oxyde de diéthyle , OxylipinesRÉSUMÉ
Hunting cycle of the carnivorous plant Venus flytrap (Dionaea muscipula Ellis) is comprised of mechanism for rapid trap closure followed by slow hermetical sealing and activation of gene expression responsible for digestion of prey and nutrient uptake. In the present study, we focus on the late phase of Venus's flytrap hunting cycle when mechanical stimulation of the prey ceases and is replaced by chemical cues. We used two nitrogen-rich compounds (chitin and protein) in addition to mechanostimulation to investigate the electrical and jasmonate signalling responsible for induction of enzyme activities. Chemical stimulation by BSA protein and chitin did not induce any additional spontaneous action potentials (APs). However, chemical stimulation by protein induced the highest levels of jasmonic acid (JA) and its isoleucine conjugate (JA-Ile) as well as the expression of studied gene encoding a cysteine protease (dionain). Although chitin is probably the first chemical agent which is in direct contact with digestive glands, presence of protein in the secured trap mimics the presence of insect prey best.
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Droseraceae , Animaux , Cyclopentanes , OxylipinesRÉSUMÉ
Date palm (Phoenix dactylifera) can accumulate as much as 1% silicon (Si), but not much is known about the mechanisms inherent to this process. Here, we investigated in detail the uptake, accumulation and distribution of Si in date palms, and the phylogeny of Si transporter genes in plants. We characterized the PdNIP2 transporter following heterologous expression in Xenopus oocytes and used qPCR to determine the relative expression of Si transporter genes. Silicon accumulation and distribution was investigated by light microscopy, scanning electron microscopy coupled with X-ray microanalysis and Raman microspectroscopy. We proved that PdNIP2-1 codes for a functional Si-permeable protein and demonstrated that PdNIP2 transporter genes were constitutively expressed in date palm. Silicon aggregates/phytoliths were found in specific stegmata cells present in roots, stems and leaves and their surfaces were composed of pure silica. Stegmata were organized on the outer surface of the sclerenchyma bundles or associated with the sclerenchyma of the vascular bundles. Phylogenetic analysis clustered NIP2 transporters of the Arecaceae in a sister position to those of the Poaceae. It is suggested, that Si uptake in date palm is mediated by a constitutively expressed Si influx transporter and accumulated as Si aggregates in stegmata cells abundant in the outer surface of the sclerenchyma bundles (fibers).
RÉSUMÉ
MAIN CONCLUSION: Nepenthes regulates enzyme activities by sensing stimuli from the insect prey. Protein is the best inductor mimicking the presence of an insect prey. Carnivorous plants of the genus Nepenthes have evolved passive pitcher traps for prey capture. In this study, we investigated the ability of chemical signals from a prey (chitin, protein, and ammonium) to induce transcription and synthesis of digestive enzymes in Nepenthes × Mixta. We used real-time PCR and specific antibodies generated against the aspartic proteases nepenthesins, and type III and type IV chitinases to investigate the induction of digestive enzyme synthesis in response to different chemical stimuli from the prey. Transcription of nepenthesins was strongly induced by ammonium, protein and live prey; chitin induced transcription only very slightly. This is in accordance with the amount of released enzyme and proteolytic activity in the digestive fluid. Although transcription of type III chitinase was induced by all investigated stimuli, a significant accumulation of the enzyme in the digestive fluid was found mainly after protein and live prey addition. Protein and live prey were also the best inducers for accumulation of type IV chitinase in the digestive fluid. Although ammonium strongly induced transcription of all investigated genes probably through membrane depolarization, strong acidification of the digestive fluid affected stability and abundance of both chitinases in the digestive fluid. The study showed that the proteins are universal inductors of enzyme activities in carnivorous pitcher plants best mimicking the presence of insect prey. This is not surprising, because proteins are a much valuable source of nitrogen, superior to chitin. Extensive vesicular activity was observed in prey-activated glands.
Sujet(s)
Caryophyllales/enzymologie , Enzymes/métabolisme , Régulation de l'expression des gènes végétaux , Protéines végétales/métabolisme , Chlorure d'ammonium/pharmacologie , Carnivorisme , Caryophyllales/physiologie , Caryophyllales/ultrastructure , Chitine/métabolisme , Enzymes/génétique , Concentration en ions d'hydrogène , Potentiels de membrane , Protéines végétales/génétique , Sérumalbumine bovine/métabolismeRÉSUMÉ
The mineral composition of cells, tissues, and organs is decisive for the functioning of the organisms, and is at the same time an indicator for understanding of physiological processes. We measured the composition of the ionome in the different tissues of maize kernels by element microanalysis, with special emphasis on silicon (Si). We therefore also measured the expression levels of the Si transporter genes ZmLsi1, ZmLsi2 and ZmLsi6, responsible for Si uptake and accumulation. Two weeks after pollination ZmLsi1 and ZmLsi6 genes were expressed, and expression continued until the final developmental stage of the kernels, while ZmLsi2 was not expressed. These results suggest that exclusively ZmLsi1 and ZmLsi6 are responsible for Si transport in various stages of kernel development. Expression level of ZmLsi genes was consistent with Si accumulation within kernel tissues. Silicon was mainly accumulated in pericarp and embryo proper and the lowest Si content was detected in soft endosperm and the scutellum. Correlation linkages between the distribution of Si and some other elements (macroelements Mg, P, S, N, P, and Ca and microelements Cl, Zn, and Fe) were found. The relation of Si with Mg was detected in all kernel tissues. The Si linkage with other elements was rather specific and found only in certain kernel tissues of maize. These relations may have effect on nutrient uptake and accumulation.
RÉSUMÉ
By using the photoconvertible fluorescence protein Dendra2 as a tag we demonstrated that neither the naturally occurring auxins indole-3-acetic acid and indole-3-butyric acid, nor the synthetic auxin analogs 1-naphthaleneacetic acid and 2,4-dichlorophenoxyacetic acid nor compounds inhibiting polar auxin transport such as 2,3,5-triiodobenzoic acid and 1-N-naphthylphthalamic acid, were able to inhibit endocytosis of the putative auxin transporter PIN-FORMED2 (PIN2) in Arabidopsis (Arabidopsis thaliana) root epidermis cells. All compounds, except Indole-3-butyric acid, repressed the recovery of the PIN2-Dendra2 plasma membrane pool after photoconversion when they were used in high concentrations. The synthetic auxin analogs 1-naphthaleneacetic acid and 2,4-dichlorophenoxyacetic acid showed the strongest inhibition. Auxins and auxin transport inhibitors suppressed also the accumulation of both newly synthesized and endocytotic PIN2 pools in Brefeldin A compartments (BFACs). Furthermore, we demonstrated that all compounds are also interfering with BFAC formation. The synthetic auxin analogs caused the highest reduction in the number and size of BFACs. We concluded that auxins and inhibitors of auxin transport do affect PIN2 turnover in the cells, but it is through the synthetic rather than the endocytotic pathway. The study also confirmed inappropriateness of the BFA-based approach to study PIN2 endocytosis because the majority of PIN2 accumulating in BFACs is newly synthesized and not derived from the plasma membrane.
Sujet(s)
Protéines d'Arabidopsis/métabolisme , Arabidopsis/métabolisme , Endocytose/effets des médicaments et des substances chimiques , Acides indolacétiques/pharmacologie , Arabidopsis/cytologie , Arabidopsis/génétique , Protéines d'Arabidopsis/génétique , Membrane cellulaire/métabolisme , Régulation de l'expression des gènes végétaux , Indoles/pharmacologie , Protéines luminescentes/génétique , Protéines luminescentes/métabolisme , Microscopie confocale , Épiderme végétal/cytologie , Épiderme végétal/génétique , Épiderme végétal/métabolisme , Facteur de croissance végétal/pharmacologie , Racines de plante/cytologie , Racines de plante/génétique , Racines de plante/métabolisme , Végétaux génétiquement modifiés , Transport des protéines/effets des médicaments et des substances chimiques , RT-PCR , Plant/cytologie , Plant/génétique , Plant/métabolisme , Imagerie accélérée/méthodesRÉSUMÉ
Zinc (Zn) is an essential microelement involved in various plant physiological processes. However, in excess, Zn becomes toxic and represents serious problem for plants resulting in Zn toxicity symptoms and decreasing biomass production. The effect of high Zn and its combination with silicon (Si) on ionome and expression level of ZmLsi genes was investigated in maize (Zea mays, L; hybrid Novania). Plants were cultivated hydroponically in different treatments: control (C), Zn (800 µM ZnSO4 · 7H2O), Si5 (5 mM of sodium silicate solution), and Si5 + Zn (combination of Zn and Si treatments). Growth of plants cultivated for 10 days was significantly inhibited in the presence of high Zn concentration and also by Zn and Si interaction in plants. Based on principal component analysis (PCA) and mineral element concentration in tissues, root ionome was significantly altered in both Zn and Si5 + Zn treatments in comparison to control. Mineral elements Mn, Fe, Ca, P, Mg, Ni, Co, and K significantly decreased, and Se increased in Zn and Si5 + Zn treatments. Shoot ionome was less affected than root ionome. Concentration of shoot Cu, Mn, and P decreased, and Mo increased in Zn and Si5 + Zn treatments. The PCA also revealed that the responsibility for ionome changes is mainly due to Zn exposure and also, but less, by Si application to Zn stressed plants. Expression level of Lsi1 and Lsi2 genes for the Si influx and efflux transporters was downregulated in roots after Si supply and even more downregulated by Zinc alone and also by Zn and Si interaction. Expression level of shoot Lsi6 gene was differently regulated in the first and second leaf. These results indicate negative effect of high Zn alone and also in interaction with Si on Lsi gene expression level and together with ionomic data, it was shown that homeostatic network of mineral elements was disrupted and caused negative alterations in mineral nutrition of young maize plants.