Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 1.313
Filtrar
1.
Nat Commun ; 11(1): 4285, 2020 08 27.
Artigo em Inglês | MEDLINE | ID: mdl-32855390

RESUMO

Plant hormone cytokinins are perceived by a subfamily of sensor histidine kinases (HKs), which via a two-component phosphorelay cascade activate transcriptional responses in the nucleus. Subcellular localization of the receptors proposed the endoplasmic reticulum (ER) membrane as a principal cytokinin perception site, while study of cytokinin transport pointed to the plasma membrane (PM)-mediated cytokinin signalling. Here, by detailed monitoring of subcellular localizations of the fluorescently labelled natural cytokinin probe and the receptor ARABIDOPSIS HISTIDINE KINASE 4 (CRE1/AHK4) fused to GFP reporter, we show that pools of the ER-located cytokinin receptors can enter the secretory pathway and reach the PM in cells of the root apical meristem, and the cell plate of dividing meristematic cells. Brefeldin A (BFA) experiments revealed vesicular recycling of the receptor and its accumulation in BFA compartments. We provide a revised view on cytokinin signalling and the possibility of multiple sites of perception at PM and ER.


Assuntos
Proteínas de Arabidopsis/metabolismo , Membrana Celular/metabolismo , Citocininas/metabolismo , Retículo Endoplasmático/metabolismo , Corantes Fluorescentes/química , Proteínas Quinases/metabolismo , Receptores de Superfície Celular/metabolismo , Arabidopsis/citologia , Arabidopsis/genética , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Brefeldina A/farmacologia , Citocininas/química , Corantes Fluorescentes/metabolismo , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Meristema/citologia , Meristema/metabolismo , Plantas Geneticamente Modificadas , Proteínas Quinases/genética , Receptores de Superfície Celular/genética , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Transdução de Sinais/efeitos dos fármacos
2.
Nat Commun ; 11(1): 4284, 2020 08 27.
Artigo em Inglês | MEDLINE | ID: mdl-32855409

RESUMO

Cytokinins are mobile multifunctional plant hormones with roles in development and stress resilience. Although their Histidine Kinase receptors are substantially localised to the endoplasmic reticulum, cellular sites of cytokinin perception and importance of spatially heterogeneous cytokinin distribution continue to be debated. Here we show that cytokinin perception by plasma membrane receptors is an effective additional path for cytokinin response. Readout from a Two Component Signalling cytokinin-specific reporter (TCSn::GFP) closely matches intracellular cytokinin content in roots, yet we also find cytokinins in extracellular fluid, potentially enabling action at the cell surface. Cytokinins covalently linked to beads that could not pass the plasma membrane increased expression of both TCSn::GFP and Cytokinin Response Factors. Super-resolution microscopy of GFP-labelled receptors and diminished TCSn::GFP response to immobilised cytokinins in cytokinin receptor mutants, further indicate that receptors can function at the cell surface. We argue that dual intracellular and surface locations may augment flexibility of cytokinin responses.


Assuntos
Arabidopsis/metabolismo , Citocininas/metabolismo , Proteínas Recombinantes/metabolismo , Adenina/análogos & derivados , Adenina/farmacologia , Arabidopsis/citologia , Arabidopsis/efeitos dos fármacos , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Líquido Extracelular/metabolismo , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Histidina Quinase/genética , Histidina Quinase/metabolismo , Mutação , Plantas Geneticamente Modificadas , Proteínas Recombinantes/genética , Transdução de Sinais
3.
PLoS One ; 15(7): e0236530, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32706831

RESUMO

Apple trees grafted on different rootstock types, including vigorous rootstock (VR), dwarfing interstock (DIR), and dwarfing self-rootstock (DSR), are widely planted in production, but the molecular determinants of tree branch architecture growth regulation induced by rootstocks are still not well known. In this study, the branch growth phenotypes of three combinations of 'Fuji' apple trees grafted on different rootstocks (VR: Malus baccata; DIR: Malus baccata/T337; DSR: T337) were investigated. The VR trees presented the biggest branch architecture. The results showed that the sugar content, sugar metabolism-related enzyme activities, and hormone content all presented obvious differences in the tender leaves and buds of apple trees grafted on these rootstocks. Transcriptomic profiles of the tender leaves adjacent to the top buds allowed us to identify genes that were potentially involved in signaling pathways that mediate the regulatory mechanisms underlying growth differences. In total, 3610 differentially expressed genes (DEGs) were identified through pairwise comparisons. The screened data suggested that sugar metabolism-related genes and complex hormone regulatory networks involved the auxin (IAA), cytokinin (CK), abscisic acid (ABA) and gibberellic acid (GA) pathways, as well as several transcription factors, participated in the complicated growth induction process. Overall, this study provides a framework for analysis of the molecular mechanisms underlying differential tree branch growth of apple trees grafted on different rootstocks.


Assuntos
Regulação da Expressão Gênica de Plantas , Malus/genética , Transdução de Sinais/genética , Açúcares/metabolismo , Ácido Abscísico/análise , Ácido Abscísico/metabolismo , Cromatografia Líquida de Alta Pressão , Citocininas/análise , Citocininas/metabolismo , Flores/genética , Flores/metabolismo , Giberelinas/análise , Giberelinas/metabolismo , Ácidos Indolacéticos/análise , Ácidos Indolacéticos/metabolismo , Malus/crescimento & desenvolvimento , Fenótipo , Folhas de Planta/genética , Folhas de Planta/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Raízes de Plantas/metabolismo , Caules de Planta/genética , Caules de Planta/fisiologia , RNA de Plantas/genética , RNA de Plantas/metabolismo , Açúcares/análise , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , alfa-Glucosidases/genética , alfa-Glucosidases/metabolismo
4.
Nat Commun ; 11(1): 3167, 2020 06 23.
Artigo em Inglês | MEDLINE | ID: mdl-32576831

RESUMO

Legumes tightly regulate nodule number to balance the cost of supporting symbiotic rhizobia with the benefits of nitrogen fixation. C-terminally Encoded Peptides (CEPs) and CLAVATA3-like (CLE) peptides positively and negatively regulate nodulation, respectively, through independent systemic pathways, but how these regulations are coordinated remains unknown. Here, we show that rhizobia, Nod Factors, and cytokinins induce a symbiosis-specific CEP gene, MtCEP7, which positively regulates rhizobial infection. Via grafting and split root studies, we reveal that MtCEP7 increases nodule number systemically through the MtCRA2 receptor. MtCEP7 and MtCLE13 expression in rhizobia-inoculated roots rely on the MtCRE1 cytokinin receptor and on the MtNIN transcription factor. MtNIN binds and transactivates MtCEP7 and MtCLE13, and a NIN Binding Site (NBS) identified within the proximal MtCEP7 promoter is required for its symbiotic activation. Overall, these results demonstrate that a cytokinin-MtCRE1-MtNIN regulatory module coordinates the expression of two antagonistic, symbiosis-related, peptide hormones from different families to fine-tune nodule number.


Assuntos
Peptídeos/química , Nodulação/fisiologia , Rhizobium/metabolismo , Fatores de Transcrição/metabolismo , Citocininas/metabolismo , Epiderme , Regulação da Expressão Gênica de Plantas , Lotus/metabolismo , Medicago truncatula , Peptídeos/genética , Proteínas de Plantas , Nodulação/genética , Raízes de Plantas/metabolismo , Regiões Promotoras Genéticas , Proteínas Quinases , Sinais Direcionadores de Proteínas/genética , Nódulos Radiculares de Plantas , Sinorhizobium meliloti/metabolismo , Simbiose
5.
PLoS One ; 15(5): e0233055, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32413087

RESUMO

Given the close relationship between cytokinins (CKs), photosynthesis and nitrogen metabolism, this study assessed the effect of arsenic (As) contamination on these metabolic components in the As-hyperaccumulators Pteris cretica L. var. Albo-lineata (Pc-A) and var. Parkerii (Pc-P) as well as the As-non-hyperaccumulator Pteris straminea Mett. ex Baker (Ps). The ferns were cultivated in a pot experiment for 23 weeks in soil spiked with As at the levels 20 and 100 mg·kg-1. For the purpose of this study, the CKs were placed into five functionally different groups according to their structure and physiological roles: bioactive forms (bCKs; CK free bases); inactive or weakly active forms (dCKs; CK N-glucosides); transport forms (tCKs; CK ribosides); storage forms (sCKs; O-glucosides); and primary products of CK biosynthesis (ppbCKs; CK nucleotides). An important finding was higher CKs total content, accumulation of sCKs and reduction of dCKs in As-hyperaccumulators in contrast to non-hyperaccumulator ferns. A significant depletion of C resources was confirmed in ferns, especially Ps, which was determined by measuring the photosynthetic rate and chlorophyll fluorescence. A fluorescence decrease signified a reduction in the C/N ratio, inducing an increase of bioactive CKs forms in Pc-P and Ps. The impact of As on N utilization was significant in As-hyperaccumulators. The glutamic acid/glutamine ratio, an indicator of primary N assimilation, diminished in all ferns with increased As level in the soil. In conclusion, the results indicate a large phenotypic diversity of Pteris species to As and suggest that the CKs composition and the glutamic acid/glutamine ratio can be used as a tool to diagnose As stress in plants.


Assuntos
Arsênico/toxicidade , Citocininas/metabolismo , Nitrogênio/metabolismo , Pteris/efeitos dos fármacos , Pteris/metabolismo , Aminoácidos/metabolismo , Biomassa , Fotossíntese/efeitos dos fármacos , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/metabolismo , Pteris/crescimento & desenvolvimento , Poluentes do Solo/toxicidade
6.
PLoS One ; 15(5): e0232762, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32379789

RESUMO

Cytokinin is an indispensable phytohormone responsible for physiological processes ranging from root development to leaf senescence. The term "cytokinin" refers to several dozen adenine-derived compounds occurring naturally in plants. Cytokinins (CKs) can be divided into various classes and forms; base forms are generally considered to be active while highly abundant cytokinin-N-glucosides (CKNGs), composed of a CK base irreversibly conjugated to a glucose molecule, are considered inactive. However, results from early CK studies suggest CKNGs do not always lack activity despite the perpetuation over several decades in the literature that they are inactive. Here we show that exogenous application of trans-Zeatin-N-glucosides (tZNGs, a specific class of CKNGs) to Arabidopsis results in CK response comparable to the application of an active CK base. These results are most apparent in senescence assays where both a CK base (tZ) and tZNGs (tZ7G, tZ9G) delay senescence in cotyledons. Further experiments involving root growth and shoot regeneration revealed tZNGs do not always have the same effects as tZ, and have largely distinct effects on the transcriptome and proteome. These data are in contrast to previous reports of CKNGs being inactive and raise questions about the function of these compounds as well as their mechanism of action.


Assuntos
Arabidopsis/crescimento & desenvolvimento , Citocininas/metabolismo , Glucosídeos/metabolismo , Raízes de Plantas/crescimento & desenvolvimento , Zeatina/metabolismo , Arabidopsis/metabolismo , Reguladores de Crescimento de Planta , Raízes de Plantas/metabolismo
7.
Artigo em Inglês | MEDLINE | ID: mdl-32460212

RESUMO

Cytokinins are important hormones involved in many aspects of plant growth and development. However, there remain many knowledge gaps with regard to their metabolism and transport mechanisms. Here, we characterise a half-size ATP binding cassette G (ABCG) transporter gene, also called white-brown complex transporter, VviABCG14, from grapevine (Vitis vinifera L. cv. Pinot noir). Quantitative real-time PCR analysis shows the expression of VviABCG14 gene is significantly increased after grape berries are treated with exogenous N-(2-chloro-4-pyridyl)-N'-phenylurea (CPPU) and trans-zeatin (tZ). Significant differences in phenotype were observed between overexpressing VviABCG14 transgenic and wild-type Arabidopsis lines grown for 12 days. The fresh weight of transgenic Arabidopsis was greater than of wild-type plants, and root lengths were greater. After growing in soil for 26 days, the vegetative growth of transgenic lines significantly greater than the wild-type and the bolting rate was lower. Hormone content analysis indicates the levels of tZ in the shoots of overexpressing transgenes are higher than in wild-types. Using the split-ubiquitin yeast membrane system and bimolecular fluorescence complementation assay we show VviABCG14 and VviABCG7 transporter can form a heterodimer. Meanwhile, VviABCG7 is also significantly induced by exogenous CPPU and tZ in grape berries. Altogether, our results suggest VviABCG14 may affect the phenotype of Arabidopsis by transporting cytokinins and VviABCG14 interacts with VviABCG7 to form a heterodimer.


Assuntos
Subfamília G de Transportadores de Cassetes de Ligação de ATP/genética , Citocininas/metabolismo , Proteínas de Plantas/genética , Vitis/genética , Arabidopsis/crescimento & desenvolvimento , Regulação da Expressão Gênica de Plantas , Plantas Geneticamente Modificadas/crescimento & desenvolvimento
8.
Nat Commun ; 11(1): 2170, 2020 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-32358503

RESUMO

Plants as non-mobile organisms constantly integrate varying environmental signals to flexibly adapt their growth and development. Local fluctuations in water and nutrient availability, sudden changes in temperature or other abiotic and biotic stresses can trigger changes in the growth of plant organs. Multiple mutually interconnected hormonal signaling cascades act as essential endogenous translators of these exogenous signals in the adaptive responses of plants. Although the molecular backbones of hormone transduction pathways have been identified, the mechanisms underlying their interactions are largely unknown. Here, using genome wide transcriptome profiling we identify an auxin and cytokinin cross-talk component; SYNERGISTIC ON AUXIN AND CYTOKININ 1 (SYAC1), whose expression in roots is strictly dependent on both of these hormonal pathways. We show that SYAC1 is a regulator of secretory pathway, whose enhanced activity interferes with deposition of cell wall components and can fine-tune organ growth and sensitivity to soil pathogens.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Citocininas/metabolismo , Resistência à Doença/genética , Ácidos Indolacéticos/metabolismo , Proteínas de Membrana/metabolismo , Reguladores de Crescimento de Planta/metabolismo , Raízes de Plantas/metabolismo , Transcriptoma/genética , Arabidopsis/genética , Arabidopsis/crescimento & desenvolvimento , Proteínas de Arabidopsis/genética , Parede Celular/química , Parede Celular/metabolismo , Endossomos/metabolismo , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas/genética , Complexo de Golgi/metabolismo , Proteínas de Membrana/genética , Raízes de Plantas/microbiologia , Plantas Geneticamente Modificadas/metabolismo , Plasmodioforídeos/patogenicidade , Via Secretória/genética , Solo , Proteínas de Transporte Vesicular/metabolismo
9.
Chemosphere ; 252: 126486, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32234629

RESUMO

Hydrogen peroxide (H2O2) acts as a significant regulatory component interrelated with signal transduction in plants. The positive role of H2O2 in plants subjected to myriad of abiotic factors has led us to comprehend that it is not only a free radical, generated as a product of oxidative stress, but also helpful in the maintenance of cellular homeostasis in crop plants. Studies over the last two centuries has indicated that H2O2 is a key molecule which regulate photosynthesis, stomatal movement, pollen growth, fruit and flower development and leaf senescence. Exogenously-sourced H2O2 at nanomolar levels functions as a signalling molecule, facilitates seed germination, chlorophyll content, stomatal opening, and delays senescence, while at elevated levels, it triggers oxidative burst to organic molecules, which could lead to cell death. Furthermore, H2O2 is also known to interplay synergistically or antagonistically with other plant growth regulators such as auxins, gibberellins, cytokinins, abscisic acid, jasmonic acid, ethylene and salicylic acid, nitric oxide and Ca2+ (as signalling molecules), and brassinosteroids (steroidal PGRs) under myriad of environmental stresses and thus, mediate plant growth and development and reactions to abiotic factors. The purpose of this review is to specify accessible knowledge on the role and dynamic mechanisms of H2O2 in mediating growth responses and plant resilience to HM stresses, and its crosstalk with other significant PGRs in controlling various processes. More recently, signal transduction by mitogen activated protein kinases and other transcription factors which attenuate HM stresses in plants have also been dissected.


Assuntos
Metais Pesados/toxicidade , Desenvolvimento Vegetal/efeitos dos fármacos , Estresse Fisiológico/fisiologia , Ácido Abscísico/metabolismo , Morte Celular , Clorofila/metabolismo , Citocininas/metabolismo , Homeostase , Peróxido de Hidrogênio/metabolismo , Ácidos Indolacéticos/metabolismo , Metais Pesados/metabolismo , Óxido Nítrico/metabolismo , Fotossíntese , Reguladores de Crescimento de Planta/metabolismo , Plantas/metabolismo , Transdução de Sinais
10.
PLoS Genet ; 16(4): e1008661, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32294082

RESUMO

In the Arabidopsis thaliana shoot apical meristem (SAM) the expression domains of Class III Homeodomain Leucine Zipper (HD-ZIPIII) and KANADI (KAN) genes are separated by a narrow boundary region from which new organs are initiated. Disruption of this boundary through either loss of function or ectopic expression of HD-ZIPIII and KAN causes ectopic or suppression of organ formation respectively, raising the question of how these transcription factors regulate organogenesis at a molecular level. In this study we develop a multi-channel FACS/RNA-seq approach to characterize global patterns of gene expression across the HD-ZIPIII-KAN1 SAM boundary. We then combine FACS, RNA-seq and perturbations of HD-ZIPIII and KAN expression to identify genes that are both responsive to REV and KAN1 and normally expressed in patterns that correlate with REV and KAN1. Our data reveal that a significant number of genes responsive to REV are regulated in opposite ways depending on time after induction, with genes associated with auxin response and synthesis upregulated initially, but later repressed. We also characterize the cell type specific expression patterns of auxin responsive genes and identify a set of genes involved in organogenesis repressed by both REV and KAN1.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/citologia , Arabidopsis/genética , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Proteínas de Homeodomínio/metabolismo , Meristema/citologia , Meristema/metabolismo , Fatores de Transcrição/metabolismo , Análise por Conglomerados , Citocininas/metabolismo , Citometria de Fluxo , Ontologia Genética , Genes de Plantas , Ácidos Indolacéticos/metabolismo , Inflorescência , Reguladores de Crescimento de Planta/metabolismo , RNA-Seq , Transdução de Sinais , Transcriptoma
11.
Int J Mol Sci ; 21(2)2020 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-32284503

RESUMO

Allotriploid poplar has a prominent vegetative growth advantage that impacts dramatically on lumber yield. The growth regulation is complex which involves abundant genes, metabolic and signaling pathways, while the information about the functional control process is very little. We used high-throughput sequencing and physiological index measurement to obtain a global overview of differences between allotriploid and diploid Populus. The genes related to plant growth advantage show a higher expression compared to diploid, and most of them are revolved around hormones, photosynthesis and product accumulation. Thus, allotriploid Populus showed more efficient photosynthesis, carbon fixation, sucrose and starch synthesis, and metabolism as well as augmented biosynthesis of auxin, cytokinin, and gibberellin. These data enable the connection of metabolic processes, signaling pathways, and specific gene activity, which will underpin the development of network models to elucidate the process of triploid Populus advantage growth.


Assuntos
Fotossíntese/genética , Reguladores de Crescimento de Planta/metabolismo , Populus/genética , Transdução de Sinais , Ciclo do Carbono/genética , Citocininas/metabolismo , Perfilação da Expressão Gênica , Heterozigoto , Sequenciamento de Nucleotídeos em Larga Escala , Ácidos Indolacéticos/metabolismo , Folhas de Planta , Populus/crescimento & desenvolvimento , Populus/fisiologia , Populus/ultraestrutura , Amido/metabolismo , Sacarose/metabolismo , Triploidia
12.
PLoS One ; 15(3): e0230110, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32163460

RESUMO

In sweet cherry trees, flowering is commercially important because the flowers, after fertilization, will generate the fruits. In P. avium, the flowering induction and flower organogensis are the first developmental steps towards flower formation and they occur within specialized organs known as floral buds during the summer, nine months before blooming. During this period the number of floral buds per tree and the bud fruitfulness (number of flowers per bud) are stablished affecting the potential yield of orchards and the plant architecture. The floral bud development is sensitive to any type of stress and the hotter and drier summers will interfere with this process and are calling for new adapted cultivars. A better understanding of the underlying molecular and hormonal mechanisms would be of help, but unlike the model plant Arabidopsis, very little is known about floral induction in sweet cherry. To explore the molecular mechanism of floral bud differentiation, high-throughput RNA sequencing was used to detect differences in the gene expression of P. avium floral buds at five differentiation stages. We found 2,982 differentially expressed genes during floral bud development. We identified genes associated with floral initiation or floral organ identity that appear to be useful biomarkers of floral development and several transcription factor families (ERF, MYB, bHLH, MADS-box and NAC gene family) with novel potential roles during floral transition in this species. We analyzed in deep the MADS-box gene family and we shed light about their key role during floral bud and organs development in P. avium. Furthermore, the hormonal-related signatures in the gene regulatory networks and the dynamic changes of absicic acid, zeatin and indolacetic acid contents in buds suggest an important role for these hormones during floral bud differentiation in sweet cherry. These data provide a rich source of novel informacion for functional and evolutionary studies about floral bud development in sweet cherry and new tools for biotechnology and breeding.


Assuntos
Perfilação da Expressão Gênica/métodos , Proteínas de Plantas/metabolismo , Prunus avium/genética , Fatores de Transcrição/metabolismo , Ácido Abscísico/metabolismo , Citocininas/metabolismo , Flores/genética , Flores/crescimento & desenvolvimento , Flores/metabolismo , Regulação da Expressão Gênica de Plantas , Biblioteca Gênica , Redes Reguladoras de Genes , Ácidos Indolacéticos/metabolismo , Filogenia , Folhas de Planta/genética , Folhas de Planta/metabolismo , Proteínas de Plantas/classificação , Proteínas de Plantas/genética , Análise de Componente Principal , Prunus avium/crescimento & desenvolvimento , Prunus avium/metabolismo , RNA-Seq , Fatores de Transcrição/classificação , Fatores de Transcrição/genética
13.
Plant Cell Rep ; 39(4): 473-487, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32016506

RESUMO

KEY MESSAGE: The non-intrinsic ABC proteins ABCI20 and ABCI21 are induced by light under HY5 regulation, localize to the ER, and ameliorate cytokinin-driven growth inhibition in young Arabidopsis thaliana seedlings. The plant ATP-binding cassette (ABC) I subfamily (ABCIs) comprises heterogeneous proteins containing any of the domains found in other ABC proteins. Some ABCIs are known to function in basic metabolism and stress responses, but many remain functionally uncharacterized. ABCI19, ABCI20, and ABCI21 of Arabidopsis thaliana cluster together in a phylogenetic tree, and are suggested to be targets of the transcription factor ELONGATED HYPOCOTYL 5 (HY5). Here, we reveal that these three ABCIs are involved in modulating cytokinin responses during early seedling development. The ABCI19, ABCI20 and ABCI21 promoters harbor HY5-binding motifs, and ABCI20 and ABCI21 expression was induced by light in a HY5-dependent manner. abci19 abci20 abci21 triple and abci20 abci21 double knockout mutants were hypersensitive to cytokinin in seedling growth retardation assays, but did not show phenotypic differences from the wild type in either control medium or auxin-, ABA-, GA-, ACC- or BR-containing media. ABCI19, ABCI20, and ABCI21 were expressed in young seedlings and the three proteins interacted with each other, forming a large protein complex at the endoplasmic reticulum (ER) membrane. These results suggest that ABCI19, ABCI20, and ABCI21 fine-tune the cytokinin response at the ER under the control of HY5 at the young seedling stage.


Assuntos
Transportadores de Cassetes de Ligação de ATP/metabolismo , Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Fatores de Transcrição de Zíper de Leucina Básica/metabolismo , Citocininas/metabolismo , Retículo Endoplasmático/metabolismo , Transportadores de Cassetes de Ligação de ATP/genética , Motivos de Aminoácidos , Arabidopsis/genética , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/efeitos da radiação , Proteínas de Arabidopsis/genética , Fatores de Transcrição de Zíper de Leucina Básica/genética , Citocininas/genética , Retículo Endoplasmático/efeitos da radiação , Regulação da Expressão Gênica de Plantas/genética , Regulação da Expressão Gênica de Plantas/efeitos da radiação , Técnicas de Inativação de Genes , Luz , Filogenia , Plantas Geneticamente Modificadas , Regiões Promotoras Genéticas , Ligação Proteica , Plântula/genética , Plântula/crescimento & desenvolvimento , Plântula/metabolismo , Plântula/efeitos da radiação
14.
Plant Reprod ; 33(1): 21-34, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31907610

RESUMO

KEY MESSAGE: Cytokinin might be an important factor to regulate floral sex at the very early stage of flower development in sacha inchi. Sacha inchi (Plukenetia volubilis, Euphorbiaceae) is characterized by having female and male flowers in a thyrse with particular differences. The mechanisms involved in the development of unisexual flowers are very poorly understood. In this study, the inflorescence and flower development of P. volubilis were investigated using light microscopy and scanning electron microscopy. We also investigated the effects of cytokinin on flower sex determination by exogenous application of 6-benzyladenine (BA) in P. volubilis. The floral development of P. volubilis was divided into eight stages, and the first morphological divergence between the male and female flowers was found to occur at stage 3. Both female and male flowers can be structurally distinguished by differences in the shape and size of the flower apex after sepal primordia initiation. There are no traces of gynoecia in male flowers or of androecia in female flowers. Exogenous application of BA effectively induced gynoecium primordia initiation and female flower development, especially at the early flower developmental stages. We propose that flower sex is determined earlier and probably occurs before flower initiation, either prior to or at inflorescence development due to the difference in the position of the female and male primordia in the inflorescence and in the time of the female and male primordia being initiated. The influence of cytokinin on female primordia during flower development in P. volubilis strongly suggests a feminization role for cytokinin in sex determination. These results indicate that cytokinin could modify the fate of the apical meristem of male flower and promote the formation of carpel primordia in P. volubilis.


Assuntos
Euphorbiaceae , Flores , Compostos de Benzil/farmacologia , Citocininas/metabolismo , Euphorbiaceae/efeitos dos fármacos , Flores/classificação , Flores/fisiologia , Flores/ultraestrutura , Regulação da Expressão Gênica de Plantas , Inflorescência/ultraestrutura , Reguladores de Crescimento de Planta/farmacologia , Purinas/farmacologia , Processos de Determinação Sexual/efeitos dos fármacos
15.
Int J Mol Sci ; 21(1)2020 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-31906415

RESUMO

To date, extensive studies have identified many classes of hormones in plants and revealed the specific, nonredundant signaling pathways for each hormone. However, plant hormone functions largely overlap in many aspects of plant development and environmental responses, suggesting that studying the crosstalk among plant hormones is key to understanding hormonal responses in plants. The phytohormone jasmonic acid (JA) is deeply involved in the regulation of plant responses to biotic and abiotic stresses. In addition, a growing number of studies suggest that JA plays an essential role in the modulation of plant growth and development under stress conditions, and crosstalk between JA and other phytohormones involved in growth and development, such as gibberellic acid (GA), cytokinin, and auxin modulate various developmental processes. This review summarizes recent findings of JA crosstalk in the modulation of plant growth and development, focusing on JA-GA, JA-cytokinin, and JA-auxin crosstalk. The molecular mechanisms underlying this crosstalk are also discussed.


Assuntos
Ciclopentanos/metabolismo , Oxilipinas/metabolismo , Desenvolvimento Vegetal/genética , Reguladores de Crescimento de Planta/metabolismo , Plantas/metabolismo , Transdução de Sinais/genética , Citocininas/genética , Citocininas/metabolismo , Regulação da Expressão Gênica de Plantas/genética , Giberelinas/metabolismo , Ácidos Indolacéticos/metabolismo , Desenvolvimento Vegetal/fisiologia , Plantas/enzimologia , Plantas/genética , Transdução de Sinais/fisiologia , Estresse Fisiológico
16.
Biomolecules ; 10(2)2020 01 25.
Artigo em Inglês | MEDLINE | ID: mdl-31991754

RESUMO

Although it has long been known that bacteria detect and react to plant chemicals to establish an interaction, the cellular signaling mechanisms involved in these perception processes have hitherto remained obscure. Some exciting recent advances in the field have described, for the first time, how some phytopathogenic bacteria sense the host plant hormones, cytokinins. These discoveries not only advance the understanding of cell signaling circuitries engaged in cytokinin sensing in non-plant organisms, but also increase our knowledge of the broad role of these ancient molecules in regulating intra- and interspecific communications.


Assuntos
Bactérias/genética , Fenômenos Fisiológicos Bacterianos/genética , Citocininas/química , Reguladores de Crescimento de Planta/química , Citocininas/metabolismo , Regulação da Expressão Gênica de Plantas , Plantas/química , Plantas/microbiologia , Transdução de Sinais/genética
17.
Plant Cell Rep ; 39(4): 431-444, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31984435

RESUMO

KEY MESSAGE: This review summarizes recent knowledge on functions of WUS and WUS-related homeobox (WOX) transcription factors in diverse signaling pathways governing shoot meristem biology and several other aspects of plant dynamics. Transcription factors (TFs) are master regulators involved in controlling different cellular and biological functions as well as diverse signaling pathways in plant growth and development. WUSCHEL (WUS) is a homeodomain transcription factor necessary for the maintenance of the stem cell niche in the shoot apical meristem, the differentiation of lateral primordia, plant cell totipotency and other diverse cellular processes. Recent research about WUS has uncovered several unique features including the complex signaling pathways that further improve the understanding of vital network for meristem biology and crop productivity. In addition, several reports bridge the gap between WUS expression and plant signaling pathway by identifying different WUS and WUS-related homeobox (WOX) genes during the formation of shoot (apical and axillary) meristems, vegetative-to-embryo transition, genetic transformation, and other aspects of plant growth and development. In this respect, the WOX family of TFs comprises multiple members involved in diverse signaling pathways, but how these pathways are regulated remains to be elucidated. Here, we review the current status and recent discoveries on the functions of WUS and newly identified WOX family members in the regulatory network of various aspects of plant dynamics.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Flores/metabolismo , Proteínas de Homeodomínio/metabolismo , Meristema/metabolismo , Brotos de Planta/metabolismo , Arabidopsis/embriologia , Arabidopsis/genética , Arabidopsis/crescimento & desenvolvimento , Proteínas de Arabidopsis/genética , Diferenciação Celular/genética , Citocininas/metabolismo , Epigênese Genética , Flores/embriologia , Flores/genética , Flores/crescimento & desenvolvimento , Proteínas de Homeodomínio/genética , Meristema/genética , Meristema/crescimento & desenvolvimento , Brotos de Planta/genética , Brotos de Planta/crescimento & desenvolvimento , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/crescimento & desenvolvimento , Plantas Geneticamente Modificadas/metabolismo , Regeneração/genética , Transdução de Sinais , Nicho de Células-Tronco , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
18.
Plant Cell Rep ; 39(4): 527-541, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31993729

RESUMO

KEY MESSAGE: Several members of WOX and KNOX gene families and several plant growth regulators, basically cytokinins and auxins, play a key role during adventitious caulogenesis in the conifer Pinus pinea. Similar to Arabidopsis thaliana, Pinus pinea shoot organogenesis is a multistep process. However, there are key differences between both species, which may alter the underlying physiological and genetic programs. It is unknown if the genic expression models during angiosperm development may be applicable to conifers. In this work, an analysis of the endogenous content of different plant growth regulators and the expression of genes putatively involved in adventitious caulogenesis in P. pinea cotyledons was conducted. A multivariate analysis of both datasets was also realized through partial least squares regression and principal component analysis to obtain an integral vision of the mechanisms involved in caulogenesis in P. pinea. Analyses show that cotyledons cultured in the presence of benzyladenine during long times (2-6 days) cluster separately from the rest of the samples, suggesting that the benzyladenine increase observed during the first hours of culture is sufficient to trigger the caulogenic response through the activation of specific developmental programs. In particular, the most relevant factors involved in this process are the cytokinins trans-zeatin, dihydrozeatin, trans-zeatin riboside and isopentenyl adenosine; the auxin indoleacetic acid; and the genes PpWUS, PpWOX5, PpKN2, PpKN3 and PipiRR1. WUS is functional in pines and has an important role in caulogenesis. Interestingly, WOX5 also seems to participate in the process, although its specific role has not been determined.


Assuntos
Cotilédone/química , Cotilédone/metabolismo , Meristema/metabolismo , Pinus/metabolismo , Reguladores de Crescimento de Planta/metabolismo , Proteínas de Plantas/metabolismo , Aminobutiratos/farmacologia , Células Cultivadas , Cromatografia Líquida de Alta Pressão , Cotilédone/efeitos dos fármacos , Cotilédone/genética , Citocininas/metabolismo , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Regulação da Expressão Gênica de Plantas/genética , Proteínas de Homeodomínio/genética , Proteínas de Homeodomínio/metabolismo , Ácidos Indolacéticos/metabolismo , Meristema/química , Meristema/genética , Pinus/química , Pinus/genética , Proteínas de Plantas/genética , Brotos de Planta/metabolismo , Sementes/efeitos dos fármacos , Sementes/crescimento & desenvolvimento , Sementes/metabolismo , Espectrometria de Massas em Tandem
19.
Int J Mol Sci ; 21(2)2020 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-31963715

RESUMO

Jatropha curcas L. is monoecious with a low female-to-male ratio, which is one of the factors restricting its seed yield. Because the phytohormone cytokinins play an essential role in flower development, particularly pistil development, in this study, we elevated the cytokinin levels in J. curcas flowers through transgenic expression of a cytokinin biosynthetic gene (AtIPT4) from Arabidopsis under the control of a J. curcas orthologue of TOMATO MADS BOX GENE 6 (JcTM6) promoter that is predominantly active in flowers. As expected, the levels of six cytokinin species in the inflorescences were elevated, and flower development was modified without any alterations in vegetative growth. In the transgenic J. curcas plants, the flower number per inflorescence was significantly increased, and most flowers were pistil-predominantly bisexual, i.e., the flowers had a huge pistil surrounded with small stamens. Unfortunately, both the male and the bisexual flowers of transgenic J. curcas were infertile, which might have resulted from the continuously high expression of the transgene during flower development. However, the number and position of floral organs in the transgenic flowers were well defined, which suggested that the determinacy of the floral meristem was not affected. These results suggest that fine-tuning the endogenous cytokinins can increase the flower number and the female-to-male ratio in J. curcas.


Assuntos
Proteínas de Arabidopsis/genética , Arabidopsis/metabolismo , Citocininas/metabolismo , Jatropha/genética , Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Vias Biossintéticas , Citocininas/genética , Flores/genética , Flores/fisiologia , Perfilação da Expressão Gênica , Regulação da Expressão Gênica no Desenvolvimento , Regulação da Expressão Gênica de Plantas , Inflorescência , Jatropha/fisiologia , Plantas Geneticamente Modificadas/fisiologia , Regiões Promotoras Genéticas , Reprodução Assexuada
20.
Ecotoxicol Environ Saf ; 189: 109989, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31784105

RESUMO

Despite of its essentiality, nickel (Ni) in excess is toxic for plants partly due to the overproduction of reactive oxygen species (ROS) and the consequent increase in oxidative stress signalling. However, in Ni-stressed plants little is known about the signal transduction of reactive nitrogen species (RNS) and protein tyrosine nitration as the protein-level consequence of increased RNS formation. Our experiments compared the nickel accumulation and tolerance, the redox signalling and the protein nitration in the agar-grown Arabidopsis thaliana and Brassica juncea exposed to Ni (50 µM nickel chloride). Studying GUS-tagged Arabidopsis lines (ARR5::GUS, ACS8::GUS and DR5::GUS) revealed that Ni-increased lateral root (LR) emergence, and concomitantly reduced LR initiation were accompanied by elevated levels of auxin, cytokinin, and ethylene in the LRs or in upper root parts, whereas Ni-induced primary root shortening is related to decreased auxin, and increased cytokinin and ethylene levels. These suggest the Ni-induced disturbance of hormonal balance in the root system. Results of the comparative study showed that weaker Ni tolerance of A. thaliana was coupled with a Ni-induced increase in RNS, ROS, and hydrogen sulfide levels, as well as with an increase in redox signalling and consequent increment of protein nitration. However, in relative Ni tolerant B. juncea, redox signalling (except for peroxynitrite) was not modified, and Ni-induced intensification of protein tyrosine nitration was less pronounced. Data collectively show that the better Ni tolerance of Brassica juncea may be related to the capability of preventing the induction of redox signalling and consequently to the slighter increase in protein nitration.


Assuntos
Arabidopsis/metabolismo , Mostardeira/metabolismo , Níquel/metabolismo , Oxirredução , Citocininas/metabolismo , Etilenos/metabolismo , Ácidos Indolacéticos/metabolismo , Estresse Oxidativo , Raízes de Plantas/metabolismo , Espécies Reativas de Nitrogênio/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA