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1.
Nat Commun ; 12(1): 5042, 2021 08 19.
Artigo em Inglês | MEDLINE | ID: mdl-34413297

RESUMO

Food production must increase significantly to sustain a growing global population. Reducing plant water loss may help achieve this goal and is especially relevant in a time of climate change. The plant cuticle defends leaves against drought, and so understanding water movement through the cuticle could help future proof our crops and better understand native ecology. Here, via mathematical modelling, we identify mechanistic properties of water movement in cuticles. We model water sorption in astomatous isolated cuticles, utilising three separate pathways of cellulose, aqueous pores and lipophilic. The model compares well to data both over time and humidity gradients. Sensitivity analysis shows that the grouping of parameters influencing plant species variations has the largest effect on sorption, those influencing cellulose are very influential, and aqueous pores less so but still relevant. Cellulose plays a significant role in diffusion and adsorption in the cuticle and the cuticle surfaces.


Assuntos
Celulose/metabolismo , Plantas/metabolismo , Água/metabolismo , Adsorção , Transporte Biológico , Difusão , Secas , Umidade , Modelos Biológicos , Permeabilidade , Epiderme Vegetal/metabolismo , Folhas de Planta/metabolismo
2.
Biochemistry (Mosc) ; 86(7): 878-886, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34284711

RESUMO

The effects of superoxide dismutase (SOD) inhibitors, diethyldithiocarbamate (DDC), triethylenetetramine (trien), and their combination with glucose on cells of the epidermis from pea leaves of different age (rapidly growing young leaves and slowly growing old leaves) was investigated. DDC and trien caused death of the guard cells as determined by destruction of their nuclei. Glucose did not affect destruction of the nuclei induced by SOD inhibitors in the cells from old leaves, but intensified it in the cells from young leaves. 2-Deoxyglucose, an inhibitor of glycolysis, and propyl gallate, SOD-mimic and antioxidant, suppressed destruction of the nuclei that was caused by SOD inhibitors and glucose in cells of the epidermis from the young, but not from the old leaves. Glucose and trien stimulated, and propyl gallate reduced generation of reactive oxygen species (ROS) in the pea epidermis as determined by the fluorescence of 2',7'-dichlorofluorescein (DCF). Carbonyl cyanide m-chlorophenylhydrazone (CCCP), a protonophoric uncoupler of oxidative and photosynthetic phosphorylation, suppressed the DCF fluorescence in the guard cells. Treatment of the cells with CCCP followed by its removal with washing increased destruction of the nuclei caused by SOD inhibitors and glucose. In young leaves, CCCP was less effective than in old ones. The findings demonstrate the effects of SOD inhibitors and glucose on the cell death and generation of ROS and could indicate glycolysis-dependent ROS production.


Assuntos
Ditiocarb/farmacologia , Glucose/metabolismo , Ervilhas/efeitos dos fármacos , Epiderme Vegetal/efeitos dos fármacos , Espécies Reativas de Oxigênio , Superóxido Dismutase/antagonistas & inibidores , Trientina/farmacologia , Morte Celular , Quelantes/farmacologia , Inibidores Enzimáticos/farmacologia , Glucose/farmacologia , Ervilhas/enzimologia , Ervilhas/metabolismo , Ervilhas/fisiologia , Epiderme Vegetal/enzimologia , Epiderme Vegetal/metabolismo , Epiderme Vegetal/fisiologia , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/enzimologia , Folhas de Planta/metabolismo , Folhas de Planta/fisiologia
3.
Nat Commun ; 12(1): 3403, 2021 06 07.
Artigo em Inglês | MEDLINE | ID: mdl-34099707

RESUMO

Developmental outcomes are shaped by the interplay between intrinsic and external factors. The production of stomata-essential pores for gas exchange in plants-is extremely plastic and offers an excellent system to study this interplay at the cell lineage level. For plants, light is a key external cue, and it promotes stomatal development and the accumulation of the master stomatal regulator SPEECHLESS (SPCH). However, how light signals are relayed to influence SPCH remains unknown. Here, we show that the light-regulated transcription factor ELONGATED HYPOCOTYL 5 (HY5), a critical regulator for photomorphogenic growth, is present in inner mesophyll cells and directly binds and activates STOMAGEN. STOMAGEN, the mesophyll-derived secreted peptide, in turn stabilizes SPCH in the epidermis, leading to enhanced stomatal production. Our work identifies a molecular link between light signaling and stomatal development that spans two tissue layers and highlights how an environmental signaling factor may coordinate growth across tissue types.


Assuntos
Arabidopsis/crescimento & desenvolvimento , Regulação da Expressão Gênica de Plantas/efeitos da radiação , Luz , Desenvolvimento Vegetal/genética , Estômatos de Plantas/crescimento & desenvolvimento , Arabidopsis/genética , Arabidopsis/efeitos da radiação , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Fatores de Transcrição de Zíper de Leucina Básica/metabolismo , Hipocótilo/metabolismo , Células do Mesofilo/metabolismo , Comunicação Parácrina/genética , Comunicação Parácrina/efeitos da radiação , Desenvolvimento Vegetal/efeitos da radiação , Epiderme Vegetal/metabolismo , Estômatos de Plantas/efeitos da radiação , Plantas Geneticamente Modificadas , Estabilidade Proteica/efeitos da radiação
4.
J Plant Physiol ; 262: 153448, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34058643

RESUMO

The halophyte ice plant (Mesembryanthemum crystallinum) converts its mode of photosynthesis from C3 to crassulacean acid metabolism (CAM) during severe water stress. During the transition to CAM, the plant induces CAM-related genes and changes its diurnal stomatal behavior to take up CO2 efficiently at night. However, limited information concerning this signaling exists. Here, we investigated the changes in the diurnal stomatal behavior of M. crystallinum during its shift in photosynthesis using a detached epidermis. M. crystallinum plants grown under C3 conditions opened their stomata during the day and closed them at night. However, CAM-induced plants closed their stomata during the day and opened them at night. Quantitative analysis of endogenous phytohormones revealed that trans-zeatin levels were high in CAM-induced plants. In contrast, the levels of jasmonic acid (JA) and JA-isoleucine were severely reduced in CAM-induced plants, specifically at night. CAM induction did not alter the levels of abscisic acid; however, inhibitors of abscisic acid synthesis suppressed CAM-induced stomatal closure. These results indicate that M. crystallinum regulates the diurnal balance of cytokinin and JA during CAM transition to alter stomatal behavior.


Assuntos
Metabolismo Ácido das Crassuláceas , Mesembryanthemum/metabolismo , Reguladores de Crescimento de Plantas/fisiologia , Estômatos de Plantas/fisiologia , Plantas Tolerantes a Sal/metabolismo , Ácido Abscísico/metabolismo , Ritmo Circadiano , Metabolismo Ácido das Crassuláceas/fisiologia , Ciclopentanos/metabolismo , Citocininas/metabolismo , Citocininas/fisiologia , Regulação da Expressão Gênica de Plantas , Mesembryanthemum/fisiologia , Oxilipinas/metabolismo , Epiderme Vegetal/metabolismo , Folhas de Planta/metabolismo , Estômatos de Plantas/metabolismo , Reação em Cadeia da Polimerase em Tempo Real , Plantas Tolerantes a Sal/fisiologia
5.
Nat Commun ; 12(1): 2739, 2021 05 20.
Artigo em Inglês | MEDLINE | ID: mdl-34016974

RESUMO

In addition to conspicuous large mesophyll chloroplasts, where most photosynthesis occurs, small epidermal chloroplasts have also been observed in plant leaves. However, the functional significance of this small organelle remains unclear. Here, we present evidence that Arabidopsis epidermal chloroplasts control the entry of fungal pathogens. In entry trials, specialized fungal cells called appressoria triggered dynamic movement of epidermal chloroplasts. This movement is controlled by common regulators of mesophyll chloroplast photorelocation movement, designated as the epidermal chloroplast response (ECR). The ECR occurs when the PEN2 myrosinase-related higher-layer antifungal system becomes ineffective, and blockage of the distinct steps of the ECR commonly decreases preinvasive nonhost resistance against fungi. Furthermore, immune components were preferentially localized to epidermal chloroplasts, contributing to antifungal nonhost resistance in the pen2 background. Our findings reveal that atypical small chloroplasts act as defense-related motile organelles by specifically positioning immune components in the plant epidermis, which is the first site of contact between the plant and pathogens. Thus, this work deepens our understanding of the functions of epidermal chloroplasts.


Assuntos
Arabidopsis/imunologia , Cloroplastos/imunologia , Resistência à Doença/imunologia , Doenças das Plantas/imunologia , Epiderme Vegetal/imunologia , Arabidopsis/genética , Arabidopsis/metabolismo , Arabidopsis/microbiologia , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Auxilinas/genética , Auxilinas/metabolismo , Proteínas de Cloroplastos/genética , Proteínas de Cloroplastos/metabolismo , Cloroplastos/metabolismo , Colletotrichum/imunologia , Colletotrichum/patogenicidade , Interações Hospedeiro-Patógeno/imunologia , Magnaporthe/imunologia , Magnaporthe/patogenicidade , Proteínas dos Microfilamentos/genética , Proteínas dos Microfilamentos/metabolismo , Mutação , N-Glicosil Hidrolases/genética , N-Glicosil Hidrolases/metabolismo , Doenças das Plantas/microbiologia , Epiderme Vegetal/citologia , Epiderme Vegetal/metabolismo , Epiderme Vegetal/microbiologia , Folhas de Planta/citologia , Folhas de Planta/imunologia , Folhas de Planta/metabolismo , Folhas de Planta/microbiologia , Plantas Geneticamente Modificadas , Pseudomonas syringae/imunologia , Pseudomonas syringae/patogenicidade
6.
Int J Mol Sci ; 22(8)2021 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-33923850

RESUMO

This review is devoted to the structure, assembly and function of cuticle. The topics are discussed from the mechanical perspective and whenever the data are available a special attention is paid to the cuticle of perianth organs, i.e., sepals, petals or tepals. The cuticle covering these organs is special in both its structure and function and some of these peculiarities are related to the cuticle mechanics. In particular, strengthening of the perianth surface is often provided by a folded cuticle that functionally resembles profiled plates, while on the surface of the petal epidermis of some plants, the cuticle is the only integral continuous layer. The perianth cuticle is distinguished also by those aspects of its mechanics and development that need further studies. In particular, more investigations are needed to explain the formation and maintenance of cuticle folding, which is typical for the perianth epidermis, and also to elucidate the mechanical properties and behavior of the perianth cuticle in situ. Gaps in our knowledge are partly due to technical problems caused by very small thicknesses of the perianth cuticle but modern tools may help to overcome these obstacles.


Assuntos
Epiderme Vegetal/ultraestrutura , Fenômenos Mecânicos , Lipídeos de Membrana/química , Lipídeos de Membrana/metabolismo , Epiderme Vegetal/metabolismo
7.
Biosci Biotechnol Biochem ; 85(5): 1114-1120, 2021 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-33765114

RESUMO

TRIPTYCHON (TRY) is one of the R3-MYB transcription factors. Its extended C-terminal 19 amino-acid region (CTRY) is considered to affect the ability of root hair differentiation in Arabidopsis. Here, to further understand the function of CTRY, it, together with GFP, was artificially fused with TRY homologs, CPC and ETC1, which do not contain such extended regions and induce root hair differentiation. Arabidopsis transgenic plants carrying the fusion proteins, CPC-CTRY-GFP and ETC1-CTRY-GFP, induced root hair differentiation as observed in those carrying the original proteins without CTRY. The expression levels of the fusion proteins in the transgenic plants were essentially the same as those of the original proteins, although their subcellular localization to nuclei of root epidermal cells was slightly changed by CTRY. Therefore, CTRY does not affect the ability of CPC and ETC1 to induce root hair differentiation when artificially fused, and its function may be restricted in TRY.


Assuntos
Proteínas de Arabidopsis/genética , Arabidopsis/genética , Proteínas de Ligação a DNA/genética , Epiderme Vegetal/genética , Raízes de Plantas/genética , Proteínas Proto-Oncogênicas c-myb/genética , Fatores de Transcrição/genética , Sequência de Aminoácidos , Arabidopsis/citologia , Arabidopsis/metabolismo , Proteínas de Arabidopsis/metabolismo , Diferenciação Celular , Proteínas de Ligação a DNA/metabolismo , Regulação da Expressão Gênica de Plantas , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Células Vegetais/metabolismo , Epiderme Vegetal/citologia , Epiderme Vegetal/metabolismo , Raízes de Plantas/citologia , Raízes de Plantas/metabolismo , Plantas Geneticamente Modificadas , Proteínas Proto-Oncogênicas c-myb/metabolismo , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos , Fatores de Transcrição/metabolismo
8.
Plant Cell ; 33(2): 381-403, 2021 04 17.
Artigo em Inglês | MEDLINE | ID: mdl-33709105

RESUMO

Homogalacturonan (HG), a component of pectin, is synthesized in the Golgi apparatus in its fully methylesterified form. It is then secreted into the apoplast where it is typically de-methylesterified by pectin methylesterases (PME). Secretion and de-esterification are critical for normal pectin function, yet the underlying transcriptional regulation mechanisms remain largely unknown. Here, we uncovered a mechanism that fine-tunes the degree of HG de-methylesterification (DM) in the mucilage that surrounds Arabidopsis thaliana seeds. We demonstrate that the APETALA2/ETHYLENE RESPONSE FACTOR (AP2/ERF) transcription factor (TF) ERF4 is a transcriptional repressor that positively regulates HG DM. ERF4 expression is confined to epidermal cells in the early stages of seed coat development. The adhesiveness of the erf4 mutant mucilage was decreased as a result of an increased DM caused by a decrease in PME activity. Molecular and genetic analyses revealed that ERF4 positively regulates HG DM by suppressing the expression of three PME INHIBITOR genes (PMEIs) and SUBTILISIN-LIKE SERINE PROTEASE 1.7 (SBT1.7). ERF4 shares common targets with the TF MYB52, which also regulates pectin DM. Nevertheless, the erf4-2 myb52 double mutant seeds have a wild-type mucilage phenotype. We provide evidence that ERF4 and MYB52 regulate downstream gene expression in an opposite manner by antagonizing each other's DNA-binding ability through a physical interaction. Together, our findings reveal that pectin DM in the seed coat is fine-tuned by an ERF4-MYB52 transcriptional complex.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Proteínas de Membrana/metabolismo , Pectinas/metabolismo , Mucilagem Vegetal/metabolismo , Proteínas Repressoras/metabolismo , Sementes/metabolismo , Fatores Genéricos de Transcrição/metabolismo , Adesividade , Arabidopsis/embriologia , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Cálcio/metabolismo , Hidrolases de Éster Carboxílico/metabolismo , Reagentes para Ligações Cruzadas/química , Esterificação , Genes de Plantas , Mutação/genética , Motivos de Nucleotídeos/genética , Fenótipo , Epiderme Vegetal/citologia , Epiderme Vegetal/metabolismo , Ligação Proteica , Proteínas Repressoras/genética
9.
Int J Mol Sci ; 22(3)2021 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-33540857

RESUMO

Yellow peel will adversely affect the appearance quality of cucumber fruit, but the metabolites and the molecular mechanism of pigment accumulation in cucumber peel remain unclear. Flavonoid metabolome and transcriptome analyses were carried out on the young peel and old peel of the color mutant L19 and the near-isogenic line L14. The results showed that there were 165 differential flavonoid metabolites in the old peel between L14 and L19. The total content of representative flavonoid metabolites in the old peel of L14 was 95 times that of L19, and 35 times that of young peel of L14, respectively. This might explain the difference of pigment accumulation in yellow peel. Furthermore, transcriptome analysis showed that there were 3396 and 1115 differentially expressed genes in the yellow color difference group (Young L14 vs. Old L14 and Old L14 vs. Old L19), respectively. These differentially expressed genes were significantly enriched in the MAPK signaling pathway-plant, plant-pathogen interaction, flavonoid biosynthesis and cutin, suberine and wax biosynthesis pathways. By analyzing the correlation between differential metabolites and differentially expressed genes, six candidate genes related to the synthesis of glycitein, kaempferol and homoeriodictyol are potentially important. In addition, four key transcription factors that belong to R2R3-MYB, bHLH51 and WRKY23 might be the major drivers of transcriptional changes in the peel between L14 and L19. Then, the expression patterns of these important genes were confirmed by qRT-PCR. These results suggested that the biosynthesis pathway of homoeriodictyol was a novel way to affect the yellowing of cucumber peel. Together, the results of this study provide a research basis for the biosynthesis and regulation of flavonoids in cucumber peel and form a significant step towards identifying the molecular mechanism of cucumber peel yellowing.


Assuntos
Cucumis sativus/metabolismo , Frutas/metabolismo , Genes de Plantas , Metaboloma , Pigmentos Biológicos/metabolismo , Epiderme Vegetal/metabolismo , Transcriptoma , Carotenoides/metabolismo , Cucumis sativus/genética , DNA de Plantas/genética , Flavonas/metabolismo , Flavonoides/metabolismo , Regulação da Expressão Gênica de Plantas , Ontologia Genética , Sistema de Sinalização das MAP Quinases , Pigmentação , Melhoramento Vegetal , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , RNA de Plantas/genética , RNA de Plantas/metabolismo , Fatores de Transcrição/metabolismo
10.
Plant Sci ; 304: 110747, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33568292

RESUMO

Anthocyanin provides a red color for apple and health benefit for human. To better understand the molecular mechanisms of regulating apple color formation, we analyzed 27 transcriptomes of fruit skin from three cultivars 'Huashuo' (red-skinned), 'Hongcuibao' (red-skinned), and 'Golden Delicious' (yellow-skinned) at 0, 2, and 6 days after bag removal. Using pairwise comparisons and weighted gene co-expression network analyses (WGCNA), we constructed 17 co-expression modules. Among them, a specific module was negatively correlated to anthocyanin accumulation. The genes in the module are enriched in flavonoid biosynthesis pathways. These pathway genes were used to construct gene co-expression network of anthocyanin accumulation. Finally, a R2R3-MYB repressor designated MdMYB28 was identified as a key hub gene in the anthocyanin metabolism network. During the anthocyanin accumulation of apple fruit skin reaching a peak, MdMYB28 expression level was negatively correlated with the anthocyanin content. MdMYB28 was shown to directly bind to the promoter of MdMYB10 in yeast one-hybrid analyses. Over-expression of MdMYB28 decreased the anthocyanin biosynthesis in tobacco flower petals, suggesting that MdMYB28 acts as a negatively regulator of anthocyanin biosynthesis.


Assuntos
Flavonoides/metabolismo , Frutas/metabolismo , Genes de Plantas/genética , Malus/genética , Epiderme Vegetal/metabolismo , Antocianinas/metabolismo , Regulação da Expressão Gênica de Plantas , Malus/metabolismo , Filogenia , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Proteínas de Plantas/fisiologia , Plantas Geneticamente Modificadas , Reação em Cadeia da Polimerase em Tempo Real , Análise de Sequência de DNA , Tabaco , Transcriptoma , Técnicas do Sistema de Duplo-Híbrido
11.
Nat Commun ; 12(1): 1267, 2021 02 24.
Artigo em Inglês | MEDLINE | ID: mdl-33627645

RESUMO

Most of the aerial organs of vascular plants are covered by a protective layer known as the cuticle, the main purpose of which is to limit transpirational water loss. Cuticles consist of an amphiphilic polyester matrix, polar polysaccharides that extend from the underlying epidermal cell wall and become less prominent towards the exterior, and hydrophobic waxes that dominate the surface. Here we report that the polarity gradient caused by this architecture renders the transport of water through astomatous olive and ivy leaf cuticles directional and that the permeation is regulated by the hydration level of the cutin-rich outer cuticular layer. We further report artificial nanocomposite membranes that are inspired by the cuticles' compositionally graded architecture and consist of hydrophilic cellulose nanocrystals and a hydrophobic polymer. The structure and composition of these cuticle-inspired membranes can easily be varied and this enables a systematic investigation of the water transport mechanism.


Assuntos
Folhas de Planta/metabolismo , Água/metabolismo , Transporte Biológico/genética , Transporte Biológico/fisiologia , Lipídeos de Membrana/metabolismo , Nanocompostos/química , Nanopartículas/química , Epiderme Vegetal/metabolismo , Ceras/metabolismo
12.
Plant J ; 105(1): 271-282, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33098198

RESUMO

RNA transport and localization represent important post-transcriptional mechanisms to determine the subcellular localization of protein synthesis. Plants have the capacity to transport messenger (m)RNA molecules beyond the cell boundaries through plasmodesmata and over long distances in the phloem. RNA viruses exploit these transport pathways to disseminate their infections and represent important model systems to investigate RNA transport in plants. Here, we present an in vivo plant RNA-labeling system based on the Escherichia coli RNA-binding protein BglG. Using the detection of RNA in mobile RNA particles formed by viral movement protein (MP) as a model, we demonstrate the efficiency and specificity of mRNA detection by the BglG system as compared with MS2 and λN systems. Our observations show that MP mRNA is specifically associated with MP in mobile MP particles but hardly with MP localized at plasmodesmata. MP mRNA is clearly absent from MP accumulating along microtubules. We show that the in vivo BglG labeling of the MP particles depends on the presence of the BglG-binding stem-loop aptamers within the MP mRNA and that the aptamers enhance the coprecipitation of BglG by MP, thus demonstrating the presence of an MP:MP mRNA complex. The BglG system also allowed us to monitor the cell-to-cell transport of the MP mRNA, thus linking the observation of mobile MP mRNA granules with intercellular MP mRNA transport. Given its specificity demonstrated here, the BglG system may be widely applicable for studying mRNA transport and localization in plants.


Assuntos
Proteínas de Bactérias , RNA Mensageiro/ultraestrutura , RNA de Plantas/ultraestrutura , Proteínas de Ligação a RNA , Escherichia coli , Proteínas de Escherichia coli , Proteínas de Fluorescência Verde , Imunoprecipitação , Microscopia de Fluorescência , Epiderme Vegetal/metabolismo , RNA Mensageiro/metabolismo , RNA de Plantas/metabolismo , Tabaco/genética
13.
Plant J ; 105(4): 870-883, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33219553

RESUMO

The absorption of water and solutes by plant leaves has been recognised since more than two centuries. Given the polar nature of water and solutes, the mechanisms of foliar uptake have been proposed to be similar for water and electrolytes, including nutrient solutions. Research efforts since the 19th century focussed on characterising the properties of cuticles and applying foliar sprays to crop plants as a tool for improving crop nutrition. This was accompanied by the development of hundreds of studies aimed at characterising the chemical and structural nature of plant cuticles from different species and the mechanisms of cuticular and, to a lower extent, stomatal penetration of water and solutes. The processes involved are complex and will be affected by multiple environmental, physico-chemical and physiological factors which are only partially clear to date. During the last decades, the body of evidence that water transport across leaf surfaces of native species may contribute to water balances (absorption and loss) at an ecosystem level has grown. Given the potential importance of foliar water absorption for many plant species and ecosystems as shown in recent studies, the aim of this review is to first integrate current knowledge on plant surface composition, structure, wettability and physico-chemical interactions with surface-deposited matter. The different mechanisms of foliar absorption of water and electrolytes and experimental procedures for tracing the uptake process are discussed before posing several outstanding questions which should be tackled in future studies.


Assuntos
Folhas de Planta/metabolismo , Água/metabolismo , Produção Agrícola , Eletrólitos/metabolismo , Permeabilidade , Epiderme Vegetal/metabolismo , Folhas de Planta/fisiologia , Estômatos de Plantas/metabolismo , Plantas/metabolismo
14.
New Phytol ; 229(1): 388-402, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-32738820

RESUMO

All aerial epidermal cells in land plants are covered by the cuticle, an extracellular hydrophobic layer that provides protection against abiotic and biotic stresses and prevents organ fusion during development. Genetic and morphological analysis of the classic maize adherent1 (ad1) mutant was combined with genome-wide binding analysis of the maize MYB transcription factor FUSED LEAVES1 (FDL1), coupled with transcriptional profiling of fdl1 mutants. We show that AD1 encodes an epidermally-expressed 3-KETOACYL-CoA SYNTHASE (KCS) belonging to a functionally uncharacterized clade of KCS enzymes involved in cuticular wax biosynthesis. Wax analysis in ad1 mutants indicates that AD1 functions in the formation of very-long-chain wax components. We demonstrate that FDL1 directly binds to CCAACC core motifs present in AD1 regulatory regions to activate its expression. Over 2000 additional target genes of FDL1, including many involved in cuticle formation, drought response and cell wall organization, were also identified. Our results identify a regulatory module of cuticle biosynthesis in maize that is conserved across monocots and eudicots, and highlight previously undescribed factors in lipid metabolism, transport and signaling that coordinate organ development and cuticle formation.


Assuntos
Regulação da Expressão Gênica de Plantas , Zea mays , Epiderme Vegetal/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Ceras , Zea mays/genética , Zea mays/metabolismo
15.
Int J Mol Sci ; 22(1)2020 Dec 28.
Artigo em Inglês | MEDLINE | ID: mdl-33379335

RESUMO

γ-Aminobutyric acid (GABA) is a widely distributed non-protein amino acid mediated the regulation of nitrate uptake and Al3+ tolerance in plants. However, there are few reports about the involvement of GABA in the regulation of iron (Fe) acquisition and translocation. Here, we show that GABA regulates Fe homeostasis in rice seedlings. Exogenous GABA decreased the chlorophyll concentration in leaves, with or without Fe supply. Over-expression of glutamate decarboxylase (GAD) gene, coding a crucial enzyme of GABA production, elevated endogenous GABA content and caused more leaf chlorosis than wild type (Nipponbare). GABA inhibited Fe transportation from roots to shoots and GABA application elevated the expression levels of Fe deficiency (FD)-related genes under conditions of Fe-sufficiency (FS), suggesting that GABA is a regulator of Fe translocation. Using Perls' blue staining, we found that more ferric iron (Fe3+) was deposited in the epidermal cells of roots treated with GABA compared with control roots. Anatomic section analysis showed that GABA treatment induced more aerenchyma formation compared with the control. Aerenchyma facilitated the oxidization of soluble ferrous iron (Fe2+) into insoluble Fe3+, resulted in Fe precipitation in the epidermis, and inhibited the transportation of Fe from roots to shoots.


Assuntos
Ferro/metabolismo , Oryza/metabolismo , Raízes de Plantas/metabolismo , Brotos de Planta/metabolismo , Plântula/metabolismo , Ácido gama-Aminobutírico/farmacologia , Transporte Biológico/efeitos dos fármacos , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Genes de Plantas , Homeostase/efeitos dos fármacos , Ferro/deficiência , Modelos Biológicos , Oryza/efeitos dos fármacos , Oryza/genética , Epiderme Vegetal/efeitos dos fármacos , Epiderme Vegetal/metabolismo , Folhas de Planta/anatomia & histologia , Folhas de Planta/efeitos dos fármacos , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Raízes de Plantas/efeitos dos fármacos , Brotos de Planta/efeitos dos fármacos , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Plântula/efeitos dos fármacos , Transcriptoma/genética
16.
BMC Plant Biol ; 20(1): 498, 2020 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-33129252

RESUMO

BACKGROUND: Cuticular wax plays important role in protecting plants from drought stress. In Arabidopsis WRI4 improves drought tolerance by regulating the biosynthesis of fatty acids and cuticular wax. Cyperus esculentus (yellow nutsedge) is a tough weed found in tropical and temperate zones as well as in cooler regions. In the current study, we report the molecular cloning of a WRI4-like gene from Cyperus esculentus and its functional characterization in Arabidopsis. RESULTS: Using RACE PCR, full-length WRI-like gene was amplified from yellow nutsedge. Phylogenetic analyses and amino acid comparison suggested it to be a WRI4-like gene. According to the tissue-specific expression data, the highest expression of WRI4-like gene was found in leaves, followed by roots and tuber. Transgenic Arabidopsis plants expressing nutsedge WRI4-like gene manifested improved drought stress tolerance. Transgenic lines showed significantly reduced stomatal conductance, transpiration rate, chlorophyll leaching, water loss and improved water use efficiency (WUE). In the absence of drought stress, expression of key genes for fatty acid biosynthesis was not significantly different between transgenic lines and WT while that of cuticular wax biosynthesis genes was significantly higher in transgenic lines than WT. The PEG-simulated drought stress significantly increased expression of key genes for fatty acid as well as wax biosynthesis in transgenic Arabidopsis lines but not in WT plants. Consistent with the gene expression data, cuticular wax load and deposition was significantly higher in stem and leaves of transgenic lines compared with WT under control as well as drought stress conditions. CONCLUSIONS: WRI4-like gene from Cyperus esculentus improves drought tolerance in Arabidopsis probably by promoting cuticular wax biosynthesis and deposition. This in turn lowers chlorophyll leaching, stomatal conductance, transpiration rate, water loss and improves water use efficiency under drought stress conditions. Therefore, CeWRI4-like gene could be a good candidate for improving drought tolerance in crops.


Assuntos
Arabidopsis/fisiologia , Cyperus/genética , Genes de Plantas/genética , Epiderme Vegetal/metabolismo , Proteínas de Plantas/genética , Ceras/metabolismo , Arabidopsis/genética , Arabidopsis/metabolismo , Clorofila/metabolismo , Cyperus/fisiologia , Desidratação , Ácidos Graxos/metabolismo , Genes de Plantas/fisiologia , Filogenia , Epiderme Vegetal/genética , Folhas de Planta/metabolismo , Proteínas de Plantas/fisiologia , Transpiração Vegetal , Plantas Geneticamente Modificadas , Reação em Cadeia da Polimerase em Tempo Real
17.
Plant Sci ; 300: 110593, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-33180718

RESUMO

CBP20 (Cap-Binding Protein 20) encodes a small subunit of nuclear Cap-Binding Complex (nCBC) that together with CBP80 binds mRNA cap. We previously described barley hvcbp20.ab mutant that demonstrated higher leaf water content and faster stomatal closure than the WT after drought stress. Hence, we presumed that the better water-saving mechanism in hvcbp20.ab may result from the lower permeability of epidermis that together with stomata action limit the water evaporation under drought stress. We asked whether hvcbp20.ab exhibited any differences in wax load on the leaf surface when subjected to drought in comparison to WT cv. 'Sebastian'. To address this question, we investigated epicuticular wax structure and chemical composition under drought stress in hvcbp20.ab mutant and its WT. We showed that hvcbp20.ab mutant exhibited the increased deposition of cuticular wax. Moreover, our gene expression results suggested a role of HvCBP20 as a negative regulator of both, the biosynthesis of waxes at the level of alkane-forming, and waxes transportation. Interestingly, we also observed increased wax deposition in Arabidopsis cbp20 mutant exposed to drought, which allowed us to describe the CBP20-regulated epicuticular wax accumulation under drought stress in a wider evolutionarily context.


Assuntos
Desidratação/fisiopatologia , Hordeum/genética , Hordeum/metabolismo , Epiderme Vegetal/metabolismo , Proteínas de Plantas/metabolismo , Proteínas de Ligação ao Cap de RNA/metabolismo , Água/metabolismo , Desidratação/genética , Regulação da Expressão Gênica de Plantas , Mutação , Epiderme Vegetal/genética , Proteínas de Plantas/genética , Proteínas de Ligação a RNA/metabolismo , Estresse Fisiológico/genética , Fatores de Transcrição/metabolismo
18.
BMC Plant Biol ; 20(1): 458, 2020 Oct 06.
Artigo em Inglês | MEDLINE | ID: mdl-33023503

RESUMO

BACKGROUND: Brassica napus L. is one of the most important oil crops in the world. However, climate-change-induced environmental stresses negatively impact on its yield and quality. Cuticular waxes are known to protect plants from various abiotic/biotic stresses. Dissecting the genetic and biochemical basis underlying cuticular waxes is important to breed cultivars with improved stress tolerance. RESULTS: Here a genome-wide association study (GWAS) of 192 B. napus cultivars and inbred lines was used to identify single-nucleotide polymorphisms (SNPs) associated with leaf waxes. A total of 202 SNPs was found to be significantly associated with 31 wax traits including total wax coverage and the amounts of wax classes and wax compounds. Next, epidermal peels from leaves of both high-wax load (HW) and low-wax load (LW) lines were isolated and used to analyze transcript profiles of all GWAS-identified genes. Consequently, 147 SNPs were revealed to have differential expressions between HW and LW lines, among which 344 SNP corresponding genes exhibited up-regulated while 448 exhibited down-regulated expressions in LW when compared to those in HW. According to the gene annotation information, some differentially expressed genes were classified into plant acyl lipid metabolism, including fatty acid-related pathways, wax and cutin biosynthesis pathway and wax secretion. Some genes involved in cell wall formation and stress responses have also been identified. CONCLUSIONS: Combination of GWAS with transcriptomic analysis revealed a number of directly or indirectly wax-related genes and their associated SNPs. These results could provide clues for further validation of SNPs for marker-assisted breeding and provide new insights into the genetic control of wax biosynthesis and improving stress tolerance of B. napus.


Assuntos
Brassica napus/genética , Genes de Plantas , Epiderme Vegetal/genética , Folhas de Planta/genética , Ceras/metabolismo , Brassica napus/metabolismo , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Estudo de Associação Genômica Ampla , Fenótipo , Epiderme Vegetal/metabolismo , Folhas de Planta/metabolismo , Polimorfismo de Nucleotídeo Único , RNA de Plantas , RNA-Seq
19.
PLoS One ; 15(8): e0237173, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32845897

RESUMO

Gentian is an important ornamental flower in Japan. The corolla of the majority of cultivated Japanese gentians have green spots, which are rarely encountered in flowers of other angiosperms. Little information is available on the functional traits of the green spots. In this study, we characterized the green spots in the Japanese gentian corolla using a number of microscopic techniques. Opto-digital microscopy revealed that a single visible green spot is composed of approximately 100 epidermal cells. The epidermal cells of a green spot formed a dome-like structure and the cell lumen contained many green structures that were granular and approximately 5 µm in diameter. The green structures emitted red autofluorescence when irradiated with 488 nm excitation light. Transmission electron microscopy revealed that the green structures contained typical thylakoids and grana, thus indicating they are chloroplasts. No grana were observed and the thylakoids had collapsed in the plastids of epidermal cells surrounding green spots. To estimate the rate of photosynthetic electron transfer of the green spots, we measured chlorophyll fluorescence using the MICROSCOPY version of an Imaging-PAM (pulse-amplitude-modulated) fluorometer. Under actinic light of 449 µmol m-2 s-1, substantial electron flow through photosystem II was observed. Observation of green spot formation during corolla development revealed that immature green spots formed at an early bud stage and developed to maturity associated with chloroplast degradation in the surrounding epidermal cells. These results confirmed that the Japanese gentian corolla contains functional chloroplasts in restricted areas of epidermal cells and indicated that a sophisticated program for differential regulation of chloroplast formation and degradation is operative in the epidermis.


Assuntos
Flores/citologia , Flores/metabolismo , Gentiana/anatomia & histologia , Tilacoides/metabolismo , Clorofila/metabolismo , Transporte de Elétrons , Japão , Microscopia Eletrônica de Transmissão , Microscopia de Fluorescência , Fotossíntese , Complexo de Proteína do Fotossistema I/metabolismo , Complexo de Proteína do Fotossistema II/metabolismo , Epiderme Vegetal/citologia , Epiderme Vegetal/metabolismo , Folhas de Planta/metabolismo
20.
J Integr Plant Biol ; 62(12): 1853-1867, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32725947

RESUMO

The shape of comparable tissues and organs is consistent among individuals of a given species, but how this consistency or robustness is achieved remains an open question. The interaction between morphogenetic factors determines organ formation and subsequent shaping, which is ultimately a mechanical process. Using a computational approach, we show that the epidermal layer is essential for the robustness of organ geometry control. Specifically, proper epidermal restriction allows organ asymmetry maintenance, and the tensile epidermal layer is sufficient to suppress local variability in growth, leading to shape robustness. The model explains the enhanced organ shape variations in epidermal mutant plants. In addition, differences in the patterns of epidermal restriction may underlie the initial establishment of organ asymmetry. Our results show that epidermal restriction can answer the longstanding question of how cellular growth noise is averaged to produce precise organ shapes, and the findings also shed light on organ asymmetry establishment.


Assuntos
Arabidopsis/citologia , Arabidopsis/metabolismo , Epiderme Vegetal/citologia , Epiderme Vegetal/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo
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