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1.
Nat Commun ; 10(1): 1744, 2019 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-30988311

RESUMO

SCM, a leucine-rich repeat receptor-like kinase, is required for root epidermal cells to appropriately interpret their location and generate the proper cell-type pattern during Arabidopsis root development. Here, via a screen for scm-like mutants we describe a new allele of the QKY gene. We find that QKY is required for the appropriate spatial expression of several epidermal cell fate regulators in a similar manner as SCM in roots, and that QKY and SCM are necessary for the efficient movement of CPC between epidermal cells. We also show that turnover of SCM is mediated by a vacuolar degradation pathway triggered by ubiquitination, and that QKY prevents this SCM ubiquitination through their physical interaction. These results suggest that QKY stabilizes SCM through interaction, and this complex facilitates CPC movement between the epidermal cells to help establish the cell-type pattern in the Arabidopsis root epidermis.


Assuntos
Proteínas de Arabidopsis/fisiologia , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/citologia , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Morfogênese , Epiderme Vegetal/citologia , Epiderme Vegetal/metabolismo , Raízes de Plantas/citologia , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/metabolismo , Proteínas Proto-Oncogênicas c-myb/metabolismo , Receptores Proteína Tirosina Quinases/genética , Receptores Proteína Tirosina Quinases/metabolismo , Transdução de Sinais
2.
Microsc Res Tech ; 82(6): 764-774, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30762920

RESUMO

Iris L. is one of the important genus of family Iridaceae, consist of 56 taxa naturally occurred in Turkey. The similarities and variations in the subgenus overlapping the taxonomic positions of the species in the subgenera and needs anatomical assessment especially by microscopic techniques. In this study, the taxonomic significance of leaf anatomical characters of 10 Iris subgenus Scorpiris taxa were studied in detail and the relationship among these taxa were evaluated using microscopy techniques. Fresh leaf samples of species were fixed in 70% alcohol solution for anatomical observation under microscope. Eleven different micromorphological features were statistically analyzed to delimit the species in subgenus. Based on morphological and anatomical similarities, we studied relationships among; (1) ssp. turcica, ssp. caucasica, I. nezahatiae and I. pseudocaucasica; (2) correlation between ssp. turcica and ssp. caucasica; (3) association of I. galatica, I. persica, ssp. margaretiae and ssp. stenophylla with each other; (4) relationship between ssp. stenophylla and ssp. margaretiae; and (5) relevance between I. aucheri and I. peshmeniana. Moreover, the taxonomy of subgenus Scorpiris has been discussed in detail with novel and diagnostic features based on micromorphological physiognomies. We found that four species in this study are endemic to Turkey, while seven are critically endangered geophytes in the country. The leaf anatomical characteristics of 10 taxa were divided into three groups. Main aim of this research was to study the taxonomy of the complex subgenus Scorpiris through microscopic techniques.


Assuntos
Iridaceae/anatomia & histologia , Iridaceae/classificação , Epiderme Vegetal/citologia , Folhas de Planta/anatomia & histologia , Microscopia , Turquia
3.
Microsc Res Tech ; 82(6): 786-802, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30801847

RESUMO

Foliar and stem epidermal anatomical features of the tribe Cynoglosseae have been studied in detail for the taxonomic identification using light microscopy (LM) and scanning electron microscopic (SEM) techniques. A comparative study was conducted on different plant parts (leaf and stem epidermal anatomy) of 25 species belonging to eight genera of the tribe Cynoglosseae (Boraginaceae) collected from different phytogeographical regions of Iran for the first time. Different qualitative and quantitative characteristics were observed in detail using LM and SEM. Results showed that although generally the stem and leaf anatomical traits were similar, but some diagnostic features were examined for distinguishing the closely related genera in the tribe. The ratio of cortex/diameter of stem and phloem/xylem, the average row number of collenchyma, palisade and spongy cells, structure of trichomes, type of indumentum and palisade arrangement were found taxonomically important. The anatomical characters were statistically analyzed using cluster analysis and principal component analysis. The study found that stem and leaf eccentrics are variable in the genus but constant within species of the same genus. Most species had typical isobilateral leaves, but some showed an incipient dorsoventrally symmetry with a layer of abaxial palisade tissue. Eglandular trichomes were observed found in all the studied species, which were recognized based on structure and function. In present study some novel characters have been observed which are of great interest to the taxonomist for the correct identification some genera delimitations. The characters studied here are of less taxonomic value and delimitating at species level.


Assuntos
Boraginaceae/anatomia & histologia , Epiderme Vegetal/citologia , Folhas de Planta/anatomia & histologia , Caules de Planta/anatomia & histologia , Biometria , Irã (Geográfico) , Microscopia , Microscopia Eletrônica de Varredura
4.
PLoS One ; 14(1): e0210141, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30682033

RESUMO

Plant leaves occur in diverse shapes. Divarication patterns that develop during early growths are one of key factors that determine leaf shapes. We utilized leaves of Microsorum pteropus, a semi-aquatic fern, and closely related varieties to analyze a variation in the divarication patterns. The leaves exhibited three major types of divarication: no lobes, bifurcation, and trifurcation (i.e., monopodial branching). Our investigation of their developmental processes, using time-lapse imaging, revealed localized growths and dissections of blades near each leaf apex. Restricted cell divisions responsible for the apical growths were confirmed using a pulse-chase strategy for EdU labeling assays.


Assuntos
Epiderme Vegetal/citologia , Folhas de Planta/crescimento & desenvolvimento , Polypodiaceae/crescimento & desenvolvimento , Divisão Celular/fisiologia , Folhas de Planta/citologia
5.
Microsc Res Tech ; 82(3): 206-223, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30633436

RESUMO

Foliar epidermal features were based on the micromorphology of trichomes types, epidermal cells and stomatal complex. Even though each feature has its own limited taxonomic value but collectively these characteristics may be systematically important especially for the discrimination and identification of complex and problematic taxa. The systematics significance of nonglandular (NGTs) and glandular trichomes (GTs), stomatal complex and epidermal cells of Lamiaceous flora were analyzed by using the light microscopy (LM) and scanning electron microscopy (SEM). Variations on the observed epidermal appendages were divided into two basic types: glandular and nonglandular. GTs can be divided into subtypes: sessile capitate, subsessile capitate, and barrel and sunken. NGTs were also divided into subtypes: dendritic, stellate, conical, falcate, simple and 1-6 cells long having granulate and smooth surface ornamentation. NGTs were the most dominant features of both adaxial and abaxial surfaces of all observed taxa. Vitex negundo, Isodon rugosus, Colebrookea oppositifolia, and Marrubium vulgare could be demarked because of their twisted like appearance of NGTs at the abaxial surface. The Lamiaceae had both hypostomatic and amphistomatic leaf. Stomata were observed as diacytic, anisocytic, and anomocytic. Epidermal cells were found to be irregular, isodiametric, and rectangular. Based on these characters a taxonomic key was developed to delimit the closely related taxa. Distribution and morphology of the foliar epidermal trichomes through SEM highlight an important taxonomic tool used by the taxonomists as an aid to the correct identification of problematic Lamiaceae taxa.


Assuntos
Lamiaceae/anatomia & histologia , Epiderme Vegetal/citologia , Folhas de Planta/citologia , Estômatos de Plantas/anatomia & histologia , Tricomas/anatomia & histologia , Lamiaceae/classificação , Microscopia Eletrônica de Varredura , Paquistão
6.
Soft Matter ; 15(2): 237-242, 2019 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-30543253

RESUMO

The mechanical behavior of cellular matter in two dimensions can be inferred from geometric information near its energetic ground state. Here it is shown that the much larger set of all metastable state energies is universally described by a systematic expansion in moments of the joint probability distribution of size (area) and topology (number of neighbors). The approach captures bounds to the entire range of metastable state energies and quantitatively identifies any such state. The resulting energy landscape is invariant across different classes of energy functionals, across simulation techniques, and across system polydispersities. The theory also finds a threshold in tissue adhesion beyond which no metastable states are possible. Mechanical properties of cellular matter in biological and technological applications can thus be identified by visual information only.


Assuntos
Cucumis/citologia , Drosophila/citologia , Termodinâmica , Algoritmos , Animais , Fenômenos Biomecânicos , Simulação por Computador , Células Epiteliais/citologia , Modelos Biológicos , Epiderme Vegetal/citologia , Probabilidade
7.
Microsc Res Tech ; 82(3): 317-332, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30582243

RESUMO

The present study is insights into foliar epidermal anatomy for characterizing clades, and their utility in taxonomic segregation of certain species of Pteridaceae from Northern Pakistan. The leaf epidermal anatomy of 10 species of Pteridaceae representing four genera were examined using light and scanning electron microscope. A micromorphological matrix was constructed for eight qualitative and 12 quantitative characters. unweighted pair group method with arithmetic means and principal components analysis statistical analysis were performed to test the validity of foliar epidermal anatomical features as method of separating species and genera, and phylogenetic clusters among species are constructed using qualitative and quantitative traits. The qualitative characters described here are shape of epidermal cells, stomata, guard cell and subsidiary cells, anticlinal wall pattern, and trichomes types which is helpful in defining groups within Pteridaceae. In addition, the size of stomata, guard cells, subsidiary cells, stomatal pore epidermal cells, and trichomes are quantitatively analyzed. All species have hypostomatic leaves. Two types of stomata were observed in studied species, anomocytic and polocytic. Anomocytic stomata were observed in three genera namely: Adiantum, Onychium, and Chielanthes whereas Pteris can be discriminated from other genera by its polocytic stomata. On the basis of multivariate analysis present study does provides sufficient information on the taxonomic importance of foliar anatomy which validate its efficacy in species and genera discrimination. From result obtained here it is further possible to use leaf micromorphologic data in ferns phylogeny and providing basis for future taxonomic delimitation in other taxa.


Assuntos
Folhas de Planta/anatomia & histologia , Estômatos de Plantas/anatomia & histologia , Pteridaceae/anatomia & histologia , Pteridaceae/classificação , Tricomas/anatomia & histologia , Microscopia Eletrônica de Varredura , Paquistão , Epiderme Vegetal/anatomia & histologia , Epiderme Vegetal/citologia , Análise de Componente Principal
8.
Plant Cell Rep ; 37(12): 1681-1692, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30229287

RESUMO

KEY MESSAGE: SmbHLH148 activated the whole biosynthetic pathways of phenolic acids and tanshinones, thus upregulated the production of both the two groups of pharmaceutical ingredients in Salvia miltiorrhiza. Phenolic acids and tanshinones are the two important groups of pharmaceutical ingredients presented in Salvia miltiorrhiza Bunge. The bHLH transcription factors could regulate secondary metabolism efficiently in plants. However, there are only some MYCs have been studied on regulation of either phenolic acids or tanshinones biosynthesis. In this study, a bHLH TF named SmbHLH148, which is homologous to AtbHLH148, AtbHLH147 and CubHLH1, was isolated and functionally characterized from S. miltiorrhiza. Transcription of SmbHLH148 could be intensely induced by ABA and also be moderately induced by MeJA and GA. SmbHLH148 is present in all the six tissues and mostly expressed in fibrous root and flowers. Subcellular localization analysis found that SmbHLH148 was localized in the nucleus. Overexpression of SmbHLH148 significantly increased not only three phenolic acids components accumulation but also three tanshinones content. Content of caffeic acid, rosmarinic acid and salvianolic acid B were reached to 2.87-, 4.00- and 5.99-fold of the control in the ObHLH148-3, respectively. Content of dihydrotanshinone I, cryptotanshinone, and tanshinone I were also present highest in ObHLH148-3, reached 2.5-, 5.04- and 3.97-fold of the control, respectively. Expression analysis of pathway genes of phenolic acids and tanshinones in transgenic lines showed that most of them were obviously upregulated. Moreover, transcription of AREB and JAZs were also induced in SmbHLH148 overexpression lines. These results suggested that SmbHLH148 might be taken part in ABA and MeJA signaling and activated almost the whole biosynthetic pathways of phenolic acids and tanshinones, thus the production of phenolic acids and tanshinones were upregulated.


Assuntos
Diterpenos de Abietano/biossíntese , Hidroxibenzoatos/metabolismo , Proteínas de Plantas/metabolismo , Raízes de Plantas/metabolismo , Salvia miltiorrhiza/metabolismo , Sequência de Aminoácidos , Vias Biossintéticas/genética , Núcleo Celular/metabolismo , Biologia Computacional , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Especificidade de Órgãos/genética , Filogenia , Epiderme Vegetal/citologia , Plantas Geneticamente Modificadas , Transporte Proteico , Salvia miltiorrhiza/genética , Regulação para Cima/genética
9.
Development ; 145(14)2018 07 23.
Artigo em Inglês | MEDLINE | ID: mdl-29950390

RESUMO

The haustorium in parasitic plants is an organ specialized for invasion and nutrient uptake from host plant tissues. Despite its importance, the developmental processes of haustoria are mostly unknown. To understand the dynamics of cell fate change and cellular lineage during haustorium development, we performed live imaging-based marker expression analysis and cell-lineage tracing during haustorium formation in the model facultative root parasite Phtheirospermum japonicum Our live-imaging analysis revealed that haustorium formation was associated with induction of simultaneous cell division in multiple cellular layers, such as epidermis, cortex and endodermis. In addition, we found that procambium-like cells, monitored by cell type-specific markers, emerged within the central region of the haustorium before xylem connection to the host plant. Our clonal analysis of cell lineages showed that cells in multiple cellular layers differentiated into procambium-like cells, whereas epidermal cells eventually transitioned into specialized cells interfacing with the host plant. Thus, our data provide a cell fate transition map during de novo haustorium organogenesis in parasitic plants.


Assuntos
Câmbio , Modelos Biológicos , Orobanchaceae , Epiderme Vegetal , Xilema , Câmbio/citologia , Câmbio/embriologia , Orobanchaceae/citologia , Orobanchaceae/embriologia , Epiderme Vegetal/citologia , Epiderme Vegetal/embriologia , Xilema/citologia , Xilema/embriologia
10.
Protoplasma ; 255(6): 1811-1825, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-29948365

RESUMO

The analysis of flowers collected at different stages of anthesis provides strong evidence to conclude that the shell-shaped hypochile and the knobs of epichile form a nectary. The scent comes from the aromatic constituents of nectar and the epichile tissue and the apices of all tepals (osmophores). The comparison between pollinated and unpollinated flowers revealed that the anthesis of unpollinated flowers lasted up to the 16th day. The nectariferous secretory cells formed single-layered epidermis and several layers of underlying parenchyma built by small, isodiametric cells with thin walls and dense cytoplasm, relatively large nuclei, supplied by collateral vascular bundles. During the floral lifespan, the residues of secreted material were higher on the hypochile cells. The lipoid-carbohydrate material and lipid globules in the cell walls and in the cytoplasm were localised. The abundance of starch grains was observed at the beginning of anthesis and their gradual reduction during the flower lifespan. At the end of anthesis in unpollinated flowers, the lipoid-carbohydrate-phenolic materials have been demonstrated. The phenolic material was the same as in plastoglobuli. The features such as irregular plasmalemma, the secretory vesicles that fuse with it, fully developed dictyosomes, numerous profiles of ER indicate vesicle-mediated process of secretion. The substances could be transported by vesicles to the periplasmic space via granulocrine secretion and then to the external surface. Both micro-channels and slightly developed periplasmic space were visible in the hypochile epidermis. This is the first time for anatomical survey of secretory tissue in pollinated and unpollinated flowers of E. helleborine.


Assuntos
Flores/anatomia & histologia , Orchidaceae/anatomia & histologia , Néctar de Plantas/fisiologia , Flores/citologia , Flores/ultraestrutura , Orchidaceae/citologia , Orchidaceae/ultraestrutura , Epiderme Vegetal/citologia , Epiderme Vegetal/ultraestrutura , Polinização/fisiologia
11.
Biomed Res Int ; 2018: 9328671, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29662905

RESUMO

Plant virus-based nanoparticles can be produced in plants on a large scale and are easily modified to introduce new functions, making them suitable for applications such as vaccination and drug delivery, tissue engineering, and in vivo imaging. The latter is often achieved using green fluorescent protein and its derivatives, but the monovalent fluorescent protein iLOV is smaller and more robust. Here, we fused the iLOV polypeptide to the N-terminus of the Potato virus X (PVX) coat protein, directly or via the Foot-and-mouth disease virus 2A sequence, for expression in Nicotiana benthamiana. Direct fusion of the iLOV polypeptide did not prevent the assembly or systemic spread of the virus and we verified the presence of fusion proteins and iLOV hybrid virus particles in leaf extracts. Compared to wild-type PVX virions, the PVX particles displaying the iLOV peptide showed an atypical, intertwined morphology. Our results confirm that a direct fusion of the iLOV fluorescent protein to filamentous PVX nanoparticles offers a promising tool for imaging applications.


Assuntos
Proteínas do Capsídeo/metabolismo , Nanopartículas/química , Peptídeos/metabolismo , Potexvirus/fisiologia , Proteínas Recombinantes de Fusão/metabolismo , Tabaco/virologia , Fluorescência , Vetores Genéticos/metabolismo , Nanopartículas/ultraestrutura , Células Vegetais/metabolismo , Doenças das Plantas/virologia , Epiderme Vegetal/citologia , Epiderme Vegetal/metabolismo , RNA de Plantas/metabolismo , Recombinação Genética/genética , Tabaco/ultraestrutura , Vírion/metabolismo
12.
Protoplasma ; 255(6): 1635-1647, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-29704049

RESUMO

Considering the importance of extrafloral nectaries (EFNs) in Fabaceae, the objectives of this research were to analyze (1) the anatomical and histochemical characteristics of the EFNs of Chamaecrista ramosa var. ramosa, C. ramosa var. curvifoliola, C. ramosa var. parvifoliola, and C. ramosa var. lucida and (2) the ultrastructure of the EFNs of C. ramosa var. ramosa. Standard techniques in plant anatomy and transmission electron microscopy were used. The anatomical analyses confirmed the characteristics described for extrafloral nectaries, evidencing three well-defined regions: epidermis, nectariferous, and subnectariferous parenchymas. Carbohydrates, proteins, pectins/mucilages, and lipids were detected by histochemical analyzes in all varieties. The ultrastructure of the EFNs of C. ramosa var. ramosa allowed the observation of microchannels at the external periclinal cell walls of the epidermis covering the secretory region. The nectariferous and subnectariferous parenchyma cells have periplasmic spaces, large plastids containing starch grains and plastoglobules, mitochondria, developed endoplasmic reticulum, large vacuoles with electron-dense contents, and membrane residues may be associated with the vacuole, suggesting the occurrence of autophagic processes. The anatomical, histochemical, and ultrastructural patterns revealed characteristics that confirm the glands of C. ramosa as extrafloral nectaries and suggest the eccrine mechanism of secretion.


Assuntos
Chamaecrista/anatomia & histologia , Néctar de Plantas/química , Néctar de Plantas/metabolismo , Chamaecrista/citologia , Chamaecrista/ultraestrutura , Epiderme Vegetal/citologia , Epiderme Vegetal/ultraestrutura
13.
Development ; 145(10)2018 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-29695610

RESUMO

The epidermis is hypothesized to play a signalling role during plant development. One class of mutants showing defects in signal transduction and radial patterning are those in sterol biosynthesis. The expectation is that living cells require sterols, but it is not clear that all cell types express sterol biosynthesis genes. The HYDRA1 (HYD1) gene of Arabidopsis encodes sterol Δ8-Δ7 isomerase, and although hyd1 seedlings are defective in radial patterning across several tissues, we show that the HYD1 gene is expressed most strongly in the root epidermis. Transgenic activation of HYD1 transcription in the epidermis of hyd1 null mutants reveals a major role in root patterning and growth. HYD1 expression in the vascular tissues and root meristem, though not endodermis or pericycle, also leads to some phenotypic rescue. Phenotypic rescue is associated with rescued patterning of the PIN1 and PIN2 auxin efflux carriers. The importance of the epidermis in controlling root growth and development is proposed to be, in part, due to its role as a site for sterol biosynthesis, and auxin is a candidate for the non-cell-autonomous signal.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/crescimento & desenvolvimento , Meristema/crescimento & desenvolvimento , Raízes de Plantas/crescimento & desenvolvimento , Esteroide Isomerases/metabolismo , Esteróis/metabolismo , Arabidopsis/embriologia , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Regulação da Expressão Gênica de Plantas/genética , Ácidos Indolacéticos/metabolismo , Proteínas de Membrana Transportadoras/metabolismo , Meristema/embriologia , Epiderme Vegetal/citologia , Epiderme Vegetal/genética , Epiderme Vegetal/metabolismo , Plântula/embriologia , Plântula/genética , Transdução de Sinais/genética , Esteroide Isomerases/genética , Ativação Transcricional/genética
14.
Microsc Res Tech ; 81(5): 474-485, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-29484766

RESUMO

Palynological features as well as comparative foliar epidermal using light and scanning electron microscope (SEM) of 17 species (10genera) of Amaranthaceae have been studied for its taxonomic significance. Different foliar and palynological micro-morphological characters were examined to explain their value in resolving the difficulty in identification. All species were amphistomatic but stomata on abaxial surface were more abundant. Taxonomically significant epidermal character including stomata type, trichomes (unicellular, multicellular, and capitate) and epidermal cells shapes (polygonal and irregular) were also observed. Pollens of this family are Polypantoporate, pores large, spheroidal, mesoporous region is sparsely to scabrate, densely psilate, and spinulose. All these characters can be active at species level for identification purpose. This study indicates that at different taxonomic levels, LM and SEM pollen and epidermal morphology is explanatory and significant to identify species and genera.


Assuntos
Amaranthaceae/ultraestrutura , Microscopia Eletrônica de Varredura/métodos , Microscopia/métodos , Epiderme Vegetal/ultraestrutura , Amaranthaceae/citologia , Epiderme Vegetal/citologia
15.
Microsc Res Tech ; 81(5): 469-473, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-29384230

RESUMO

Common mulberry weed (Fatoua villosa (Thunb.) Nakai) and creeping amaranth (Amaranthus crassipes Schlecht) are reported for the first time in Pakistan's flora as these were not listed in any other literature nor identified before in Pakistan. Plants were found as a result of taxonomic studies performed in 2013 in Peshawar, Pakistan. Detail study was performed for the exact identification. Morphological results were compared with Flora of China and Flora of North America. Plant distribution along with its habitat and adjacent species was also recorded. Scanning electron and light microscopy was performed for the confirmation of epidermal appendages on leaf epidermis and palyno-morphological characters.


Assuntos
Amaranthus/ultraestrutura , Epiderme Vegetal/ultraestrutura , Amaranthus/citologia , Ecossistema , Microscopia , Microscopia Eletrônica de Varredura , Epiderme Vegetal/citologia , Folhas de Planta/citologia , Folhas de Planta/ultraestrutura
16.
Development ; 145(6)2018 03 21.
Artigo em Inglês | MEDLINE | ID: mdl-29467245

RESUMO

Plants, with cells fixed in place by rigid walls, often utilize spatial and temporally distinct cell division programs to organize and maintain organs. This leads to the question of how developmental regulators interact with the cell cycle machinery to link cell division events with particular developmental trajectories. In Arabidopsis leaves, the development of stomata, two-celled epidermal valves that mediate plant-atmosphere gas exchange, relies on a series of oriented stem cell-like asymmetric divisions followed by a single symmetric division. The stomatal lineage is embedded in a tissue in which other cells transition from proliferation to postmitotic differentiation earlier, necessitating stomatal lineage-specific factors to prolong competence to divide. We show that the D-type cyclin, CYCD7;1, is specifically expressed just prior to the symmetric guard cell-forming division, and that it is limiting for this division. Further, we find that CYCD7;1 is capable of promoting divisions in multiple contexts, likely through RBR1-dependent promotion of the G1/S transition, but that CYCD7;1 is regulated at the transcriptional level by cell type-specific transcription factors that confine its expression to the appropriate developmental window.


Assuntos
Arabidopsis/metabolismo , Divisão Celular/genética , Ciclina D/metabolismo , Estômatos de Plantas/citologia , Arabidopsis/citologia , Arabidopsis/fisiologia , Proteínas de Arabidopsis/metabolismo , Ciclo Celular/genética , Linhagem da Célula/genética , Regulação da Expressão Gênica de Plantas/genética , Epiderme Vegetal/citologia , Folhas de Planta/citologia , Folhas de Planta/metabolismo , Estômatos de Plantas/metabolismo , Reação em Cadeia da Polimerase em Tempo Real
17.
Dev Biol ; 435(1): 1-5, 2018 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-29337129

RESUMO

An R3-type MYB transcription factor, CAPRICE (CPC), is known to promote root hair cell differentiation in Arabidopsis root epidermis. The CPC protein moves from non-hair cells to the neighboring cells, and acts as an inducer of root hair formation. In contrast, we previously showed that the CPC homolog, ENHANCER OF TRY AND CPC1 (ETC1), does not move between the root epidermal cells. To clarify the critical difference in the cell-to-cell movement ability of CPC and ETC1 proteins, we generated five different chimeras of CPC and ETC1. As expected, four of the five chimeric proteins with substitution of CPC amino acids with those of ETC1 induced many root hair and no-trichome phenotype, like CPC. These chimeric proteins essentially maintained the cell-to-cell movement ability of CPC. However, one chimeric protein in which ETC1 was sandwiched between the CPC-specific movement motifs of S1 and S2 did not induce ectopic root hair formation. This chimeric protein did not move between the cells. These results indicate that the maintenance of not only the S1 and S2 motifs but also the precise structure of CPC protein might be necessary for the cell-to-cell movement of CPC. Our results should help in further unraveling of the roles of these MYB transcription factors in root hair formation.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Movimento Celular/fisiologia , Mutação de Sentido Incorreto , Epiderme Vegetal/metabolismo , Raízes de Plantas/metabolismo , Proteínas Proto-Oncogênicas c-myb/metabolismo , Motivos de Aminoácidos , Substituição de Aminoácidos , Arabidopsis/citologia , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Epiderme Vegetal/citologia , Epiderme Vegetal/genética , Raízes de Plantas/citologia , Raízes de Plantas/genética , Proteínas Proto-Oncogênicas c-myb/genética
18.
Plant Physiol ; 176(1): 432-449, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-29192026

RESUMO

The leaf epidermis is a biomechanical shell that influences the size and shape of the organ. Its morphogenesis is a multiscale process in which nanometer-scale cytoskeletal protein complexes, individual cells, and groups of cells pattern growth and define macroscopic leaf traits. Interdigitated growth of neighboring cells is an evolutionarily conserved developmental strategy. Understanding how signaling pathways and cytoskeletal proteins pattern cell walls during this form of tissue morphogenesis is an important research challenge. The cellular and molecular control of a lobed cell morphology is currently thought to involve PIN-FORMED (PIN)-type plasma membrane efflux carriers that generate subcellular auxin gradients. Auxin gradients were proposed to function across cell boundaries to encode stable offset patterns of cortical microtubules and actin filaments between adjacent cells. Many models suggest that long-lived microtubules along the anticlinal cell wall generate local cell wall heterogeneities that restrict local growth and specify the timing and location of lobe formation. Here, we used Arabidopsis (Arabidopsis thaliana) reverse genetics and multivariate long-term time-lapse imaging to test current cell shape control models. We found that neither PIN proteins nor long-lived microtubules along the anticlinal wall predict the patterns of lobe formation. In fields of lobing cells, anticlinal microtubules are not correlated with cell shape and are unstable at the time scales of cell expansion. Our analyses indicate that anticlinal microtubules have multiple functions in pavement cells and that lobe initiation is likely controlled by complex interactions among cell geometry, cell wall stress patterns, and transient microtubule networks that span the anticlinal and periclinal walls.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/citologia , Arabidopsis/metabolismo , Microtúbulos/metabolismo , Morfogênese , Folhas de Planta/citologia , Folhas de Planta/metabolismo , Membrana Celular/metabolismo , Forma Celular , Parede Celular/metabolismo , Processamento de Imagem Assistida por Computador , Mutação/genética , Epiderme Vegetal/citologia , Transporte Proteico , Transdução de Sinais , Fatores de Tempo
19.
Plant Physiol ; 176(1): 378-391, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-29084900

RESUMO

Polar nuclear migration is crucial during the development of diverse eukaryotes. In plants, root hair growth requires polar nuclear migration into the outgrowing hair. However, knowledge about the dynamics and the regulatory mechanisms underlying nuclear movements in root epidermal cells remains limited. Here, we show that both auxin and Rho-of-Plant (ROP) signaling modulate polar nuclear position at the inner epidermal plasma membrane domain oriented to the cortical cells during cell elongation as well as subsequent polar nuclear movement to the outer domain into the emerging hair bulge in Arabidopsis (Arabidopsis thaliana). Auxin signaling via the nuclear AUXIN RESPONSE FACTOR7 (ARF7)/ARF19 and INDOLE ACETIC ACID7 pathway ensures correct nuclear placement toward the inner membrane domain. Moreover, precise inner nuclear placement relies on SPIKE1 Rho-GEF, SUPERCENTIPEDE1 Rho-GDI, and ACTIN7 (ACT7) function and to a lesser extent on VTI11 vacuolar SNARE activity. Strikingly, the directionality and/or velocity of outer polar nuclear migration into the hair outgrowth along actin strands also are ACT7 dependent, auxin sensitive, and regulated by ROP signaling. Thus, our findings provide a founding framework revealing auxin and ROP signaling of inner polar nuclear position with some contribution by vacuolar morphology and of actin-dependent outer polar nuclear migration in root epidermal hair cells.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/enzimologia , Núcleo Celular/metabolismo , Polaridade Celular , Proteínas de Ligação ao GTP/metabolismo , Ácidos Indolacéticos/metabolismo , Epiderme Vegetal/citologia , Raízes de Plantas/citologia , Transdução de Sinais , Arabidopsis/citologia , Etilenos/metabolismo , Movimento , Mutação/genética , Vacúolos/metabolismo
20.
Plant Physiol ; 176(1): 392-405, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-29122988

RESUMO

Both endogenous plant proteins and viral movement proteins associate with microtubules to promote their movement through plasmodesmata. The association of viral movement proteins with microtubules facilitates the formation of virus-associated replication complexes, which are required for the amplification and subsequent spread of the virus. However, the role of microtubules in the intercellular movement of plant proteins is less clear. Here we show that the SHORT-ROOT (SHR) protein, which moves between cells in the root to regulate root radial patterning, interacts with a type-14 kinesin, KINESIN G (KinG). KinG is a calponin homology domain kinesin that directly interacts with the SHR-binding protein SIEL (SHR-INTERACING EMBRYONIC LETHAL) and localizes to both microtubules and actin. Since SIEL and SHR associate with endosomes, we suggest that KinG serves as a linker between SIEL, SHR, and the plant cytoskeleton. Loss of KinG function results in a decrease in the intercellular movement of SHR and an increase in the sensitivity of SHR movement to treatment with oryzalin. Examination of SHR and KinG localization and dynamics in live cells suggests that KinG is a nonmotile kinesin that promotes the pausing of SHR-associated endosomes. We suggest a model in which interaction of KinG with SHR allows for the formation of stable movement complexes that facilitate the cell-to-cell transport of SHR.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Espaço Extracelular/metabolismo , Espaço Intracelular/metabolismo , Cinesina/metabolismo , Fatores de Transcrição/metabolismo , Actinas/metabolismo , Proteínas de Arabidopsis/química , Compostos Bicíclicos Heterocíclicos com Pontes/farmacologia , Dinitrobenzenos/farmacologia , Endossomos/metabolismo , Cinesina/química , Meristema/metabolismo , Microtúbulos/metabolismo , Modelos Biológicos , Mutação/genética , Epiderme Vegetal/citologia , Folhas de Planta/citologia , Raízes de Plantas/metabolismo , Domínios Proteicos , Transporte Proteico , Especificidade da Espécie , Frações Subcelulares/metabolismo , Sulfanilamidas/farmacologia , Tiazolidinas/farmacologia , Tabaco/citologia
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