Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 79
Filtrar
1.
Plant Cell ; 33(8): 2850-2868, 2021 08 31.
Artigo em Inglês | MEDLINE | ID: mdl-34125207

RESUMO

Pollen wall assembly is crucial for pollen development and plant fertility. The durable biopolymer sporopollenin and the constituents of the tryphine coat are delivered to developing pollen grains by the highly coordinated secretory activity of the surrounding tapetal cells. The role of membrane trafficking in this process, however, is largely unknown. In this study, we used Arabidopsis thaliana to characterize the role of two late-acting endosomal sorting complex required for transport (ESCRT) components, ISTL1 and LIP5, in tapetal function. Plants lacking ISTL1 and LIP5 form pollen with aberrant exine patterns, leading to partial pollen lethality. We found that ISTL1 and LIP5 are required for exocytosis of plasma membrane and secreted proteins in the tapetal cells at the free microspore stage, contributing to pollen wall development and tryphine deposition. Whereas the ESCRT machinery is well known for its role in endosomal trafficking, the function of ISTL1 and LIP5 in exocytosis is not a typical ESCRT function. The istl1 lip5 double mutants also show reduced intralumenal vesicle concatenation in multivesicular endosomes in both tapetal cells and developing pollen grains as well as morphological defects in early endosomes/trans-Golgi networks, suggesting that late ESCRT components function in the early endosomal pathway and exocytosis.


Assuntos
Proteínas de Arabidopsis/genética , Arabidopsis/metabolismo , Complexos Endossomais de Distribuição Requeridos para Transporte/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/genética , Proteínas Nucleares/genética , Pólen/metabolismo , Subfamília G de Transportadores de Cassetes de Ligação de ATP/genética , Subfamília G de Transportadores de Cassetes de Ligação de ATP/metabolismo , Arabidopsis/fisiologia , Proteínas de Arabidopsis/metabolismo , Complexos Endossomais de Distribuição Requeridos para Transporte/genética , Regulação da Expressão Gênica de Plantas , Células Germinativas Vegetais/crescimento & desenvolvimento , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Lipídeos , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Proteínas Nucleares/metabolismo , Raízes de Plantas/citologia , Raízes de Plantas/genética , Plantas Geneticamente Modificadas , Pólen/fisiologia , Sementes/genética , Sementes/crescimento & desenvolvimento , Ceras/química , Ceras/metabolismo
2.
New Phytol ; 238(4): 1461-1478, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-36829299

RESUMO

Seeds slowly accumulate damage during storage, which ultimately results in germination failure. The seed coat protects the embryo from the external environment, and its composition is critical for seed longevity. Flavonols accumulate in the outer integument. The link between flavonol composition and outer integument development has not been explored. Genetic, molecular and ultrastructural assays on loss-of-function mutants of the flavonoid biosynthesis pathway were used to study the effect of altered flavonoid composition on seed coat development and seed longevity. Controlled deterioration assays indicate that loss of function of the flavonoid 3' hydroxylase gene TT7 dramatically affects seed longevity and seed coat development. Outer integument differentiation is compromised from 9 d after pollination in tt7 developing seeds, resulting in a defective suberin layer and incomplete degradation of seed coat starch. These distinctive phenotypes are not shared by other mutants showing abnormal flavonoid composition. Genetic analysis indicates that overaccumulation of kaempferol-3-rhamnoside is mainly responsible for the observed phenotypes. Expression profiling suggests that multiple cellular processes are altered in the tt7 mutant. Overaccumulation of kaempferol-3-rhamnoside in the seed coat compromises normal seed coat development. This observation positions TRANSPARENT TESTA 7 and the UGT78D1 glycosyltransferase, catalysing flavonol 3-O-rhamnosylation, as essential players in the modulation of seed longevity.


Assuntos
Arabidopsis , Arabidopsis/genética , Longevidade , Sementes/metabolismo , Flavonoides/metabolismo , Flavonóis/metabolismo
3.
Plant Physiol ; 189(4): 2144-2158, 2022 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-35512195

RESUMO

The cuticle, a hydrophobic layer of cutin and waxes synthesized by plant epidermal cells, is the major barrier to water loss when stomata are closed. Dissecting the genetic architecture of natural variation for maize (Zea mays L.) leaf cuticular conductance (gc) is important for identifying genes relevant to improving crop productivity in drought-prone environments. To this end, we performed an integrated genome- and transcriptome-wide association studies (GWAS and TWAS) to identify candidate genes putatively regulating variation in leaf gc. Of the 22 plausible candidate genes identified, 4 were predicted to be involved in cuticle precursor biosynthesis and export, 2 in cell wall modification, 9 in intracellular membrane trafficking, and 7 in the regulation of cuticle development. A gene encoding an INCREASED SALT TOLERANCE1-LIKE1 (ISTL1) protein putatively involved in intracellular protein and membrane trafficking was identified in GWAS and TWAS as the strongest candidate causal gene. A set of maize nested near-isogenic lines that harbor the ISTL1 genomic region from eight donor parents were evaluated for gc, confirming the association between gc and ISTL1 in a haplotype-based association analysis. The findings of this study provide insights into the role of regulatory variation in the development of the maize leaf cuticle and will ultimately assist breeders to develop drought-tolerant maize for target environments.


Assuntos
Estudo de Associação Genômica Ampla , Zea mays , Folhas de Planta/metabolismo , Transcriptoma , Ceras/metabolismo , Zea mays/metabolismo
4.
Proc Natl Acad Sci U S A ; 117(22): 12464-12471, 2020 06 02.
Artigo em Inglês | MEDLINE | ID: mdl-32424100

RESUMO

Plant cuticles are composed of wax and cutin and evolved in the land plants as a hydrophobic boundary that reduces water loss from the plant epidermis. The expanding maize adult leaf displays a dynamic, proximodistal gradient of cuticle development, from the leaf base to the tip. Laser microdissection RNA Sequencing (LM-RNAseq) was performed along this proximodistal gradient, and complementary network analyses identified potential regulators of cuticle biosynthesis and deposition. A weighted gene coexpression network (WGCN) analysis suggested a previously undescribed function for PHYTOCHROME-mediated light signaling during the regulation of cuticular wax deposition. Genetic analyses reveal that phyB1 phyB2 double mutants of maize exhibit abnormal cuticle composition, supporting the predictions of our coexpression analysis. Reverse genetic analyses also show that phy mutants of the moss Physcomitrella patens exhibit abnormal cuticle composition, suggesting an ancestral role for PHYTOCHROME-mediated, light-stimulated regulation of cuticle development during plant evolution.


Assuntos
Folhas de Planta/crescimento & desenvolvimento , Transcriptoma , Zea mays/genética , Bryopsida/genética , Bryopsida/metabolismo , Bryopsida/efeitos da radiação , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas/efeitos da radiação , Luz , Folhas de Planta/genética , Folhas de Planta/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Transcriptoma/efeitos da radiação , Zea mays/crescimento & desenvolvimento , Zea mays/metabolismo , Zea mays/efeitos da radiação
5.
J Appl Dev Psychol ; 86: 101547, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37153355

RESUMO

Considering the health outcomes of loneliness, it is important to understand the effects of the COVID-19 pandemic for older adults to facilitate detection and intervention. The aim of this study was to examine loneliness among Spanish older adults during the first wave lockdown and associated factors, in comparison to younger adults. An online survey was completed by 3508 adults (401 aged 60 or above). Older adults felt higher social loneliness than younger adults, but lower emotional loneliness. Living alone, poor mental health, and poor healthy habits were related to higher loneliness for both age groups. The results suggest that loneliness should be an important factor in primary care, and prevention efforts should be taken, e.g., by generating open and safe community spaces and contexts for social interaction and promoting the access and ability to use technologies that maintain social connections.

6.
J Gerontol Soc Work ; 66(7): 960-980, 2023 10.
Artigo em Inglês | MEDLINE | ID: mdl-37070848

RESUMO

Neurodegenerative diseases (NDs) are a major cause of dependency among elderly and affect the entire family unit. However, the literature has paid little attention to Family Quality of Life (FQOL) and focused on the patient and the main caregiver. The aim was to analyze the FQOL of people with NDs from a systemic perspective and to identify associated factors. A sample of 300 family caregivers from the cross-border region of Spain-Portugal completed the FQOLS - ND, which collected FQOL global and domain-level scores in terms of attainment and satisfaction. The highest rates of FQOL were obtained for the domain Family relations and the lowest for Support from services. The level of perceived barriers to social-health services emerged as the strongest predictor of global FQOL in all models. It is essential to reduce the obstacles to access social-health services and provide the family with resources according to their needs, especially in rural areas.


Assuntos
Doenças Neurodegenerativas , Qualidade de Vida , Humanos , Idoso , Inquéritos e Questionários , Apoio Social , Cuidadores , Família
7.
Plant Physiol ; 186(3): 1606-1615, 2021 07 06.
Artigo em Inglês | MEDLINE | ID: mdl-33779764

RESUMO

Physical dormancy in seeds exists widely in seed plants and plays a vital role in maintaining natural seed banks. The outermost cuticle of the seed coat forms a water-impermeable layer, which is critical for establishing seed physical dormancy. We previously set up the legume plant Medicago truncatula as an excellent model for studying seed physical dormancy, and our studies revealed that a class II KNOTTED-like homeobox, KNOX4, is a transcription factor critical for controlling hardseededness. Here we report the function of a seed coat ß-ketoacyl-CoA synthase, KCS12. The expression level of KCS12 is significantly downregulated in the knox4 mutant. The KCS12 gene is predominantly expressed in the seed coat, and seed development in the M. truncatula kcs12 mutant is altered. Further investigation demonstrated that kcs12 mutant seeds lost physical dormancy and were able to absorb water without scarification treatment. Chemical analysis revealed that concentrations of C24:0 lipid polyester monomers are significantly decreased in mutant seeds, indicating that KCS12 is an enzyme that controls the production of very long chain lipid species in the seed coat. A chromatin immunoprecipitation assay demonstrated that the expression of KCS12 in the seed coat is directly regulated by the KNOX4 transcription factor. These findings define a molecular mechanism by which KNOX4 and KCS12 control formation of the seed coat and seed physical dormancy.


Assuntos
3-Oxoacil-(Proteína de Transporte de Acila) Sintase/metabolismo , Germinação/genética , Medicago truncatula/crescimento & desenvolvimento , Medicago truncatula/genética , Medicago truncatula/metabolismo , Dormência de Plantas/genética , Sementes/genética , 3-Oxoacil-(Proteína de Transporte de Acila) Sintase/genética , Regulação da Expressão Gênica de Plantas , Genes Homeobox , Genes de Plantas , Variação Genética , Genótipo , Germinação/fisiologia , Dormência de Plantas/fisiologia , Sementes/crescimento & desenvolvimento , Sementes/metabolismo
8.
Health Qual Life Outcomes ; 20(1): 76, 2022 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-35525943

RESUMO

BACKGROUND: The diagnosis of a neurodegenerative disease (ND) produces profound changes in the quality of life of the affected families. Despite the vital importance of these processes, the scientific literature has addressed this topic almost exclusively relating to the main caregiver or using limited approaches. Thus, the main objective of this research is to achieve a deeper understanding of the quality of family life of people with a neurodegenerative disease, following a mixed-method approach that combines quantitative and qualitative methodology. METHODS: The quantitative instrument was the Spanish version of the Family Quality of Life Survey-Neurodegenerative Disease (FQOLS-ND), which was completed by 300 participating families. The qualitative methodology was used in two focus groups with family caregivers, with a total of 21 participants. RESULTS: On the one hand, confirmation of the dimensional structure of the scale in the focus groups was obtained and, on the other hand, the results of family quality of life in attainment and satisfaction were shown to be high for Family Relations and Careers and Planning for Careers and low for Support from Services and Leisure and Recreation. CONCLUSIONS: The results of this study, through the combination of quantitative and qualitative information, helps to identify key issues to optimize services that respond to the priority needs of families.


Assuntos
Doenças Neurodegenerativas , Qualidade de Vida , Cuidadores , Família , Humanos
9.
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
10.
New Phytol ; 231(2): 679-694, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-33864680

RESUMO

Cutin and suberin are lipid polyesters deposited in specific apoplastic compartments. Their fundamental roles in plant biology include controlling the movement of gases, water and solutes, and conferring pathogen resistance. Both cutin and suberin have been shown to be present in the Arabidopsis seed coat where they regulate seed dormancy and longevity. In this study, we use accelerated and natural ageing seed assays, glutathione redox potential measures, optical and transmission electron microscopy and gas chromatography-mass spectrometry to demonstrate that increasing the accumulation of lipid polyesters in the seed coat is the mechanism by which the AtHB25 transcription factor regulates seed permeability and longevity. Chromatin immunoprecipitation during seed maturation revealed that the lipid polyester biosynthetic gene long-chain acyl-CoA synthetase 2 (LACS2) is a direct AtHB25 binding target. Gene transfer of this transcription factor to wheat and tomato demonstrated the importance of apoplastic lipid polyesters for the maintenance of seed viability. Our work establishes AtHB25 as a trans-species regulator of seed longevity and has identified the deposition of apoplastic lipid barriers as a key parameter to improve seed longevity in multiple plant species.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Arabidopsis/genética , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Regulação da Expressão Gênica de Plantas , Genes Homeobox , Sementes/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
11.
Health Qual Life Outcomes ; 19(1): 172, 2021 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-34193154

RESUMO

BACKGROUND: Neurodegenerative diseases (NDs) are one of the main causes of disability and dependence that have a great impact both on the quality of life of people with disabilities and their families. A majority of people with NDs receive care and support from the family, but there is no tool in Spain with which to measure whole-family QOL. The aim of this study was the translation, cultural adaptation, and validation of the FQOLS-Dementia into Spanish to assess FQOL among family members of individuals with NDs who live in the Spain-Portugal cross-border area. METHOD: The Spanish version was translated and adapted following the international guidelines for cross-cultural adaptation tests. A sample of 300 family caregivers was interviewed, applying an adapted version of the Family Quality Survey (FQOLS-Dementia). Confirmatory factor analysis was performed to validate the factor structure, and convergent validity was examined with Pearson's correlation coefficients of the global FQOL with the domains. Internal consistency reliability was determined using Cronbach's alpha. RESULTS: The domain structure of the FQOLS-ND showed a good fit. In the convergent validity, it was found that the total score and the subscale domain scores were associated with the global FQOL score, except for the Values domain. Internal consistency of nine domain subscales was strong (α = 0.80 to 0.91), and excellent for the total FQOL (α = 0.85) and the global FQOL (α = 0.87). CONCLUSION: The FQOLS-ND presented good validity and reliability in caregiver families with individuals with ND, so its application shows its usefulness in detecting areas of improvement and intervention strategies for FQOL in the Spain-Portugal cross-border area.


Assuntos
Cuidadores/psicologia , Família/psicologia , Doenças Neurodegenerativas/terapia , Qualidade de Vida , Inquéritos e Questionários/normas , Adulto , Análise Fatorial , Humanos , Masculino , Pessoa de Meia-Idade , Psicometria/instrumentação , Reprodutibilidade dos Testes , Espanha , Traduções
12.
Plant Cell Environ ; 43(2): 315-326, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31600827

RESUMO

Permeability is a crucial trait that affects seed longevity and is regulated by different polymers including proanthocyanidins, suberin, cutin and lignin located in the seed coat. By testing mutants in suberin transport and biosynthesis, we demonstrate the importance of this biopolymer to cope with seed deterioration. Transcriptomic analysis of cog1-2D, a gain-of-function mutant with increased seed longevity, revealed the upregulation of several peroxidase genes. Reverse genetics analysing seed longevity uncovered redundancy within the seed coat peroxidase gene family; however, after controlled deterioration treatment, seeds from the prx2 prx25 double and prx2 prx25 prx71 triple mutant plants presented lower germination than wild-type plants. Transmission electron microscopy analysis of the seed coat of these mutants showed a thinner palisade layer, but no changes were observed in proanthocyanidin accumulation or in the cuticle layer. Spectrophotometric quantification of acetyl bromide-soluble lignin components indicated changes in the amount of total polyphenolics derived from suberin and/or lignin in the mutant seeds. Finally, the increased seed coat permeability to tetrazolium salts observed in the prx2 prx25 and prx2 prx25 prx71 mutant lines suggested that the lower permeability of the seed coats caused by altered polyphenolics is likely to be the main reason explaining their reduced seed longevity.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Peroxidases/metabolismo , Sementes/metabolismo , Fatores de Transcrição/metabolismo , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Parede Celular/metabolismo , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Germinação/genética , Germinação/fisiologia , Lignina , Metabolismo dos Lipídeos , Lipídeos , Lipídeos de Membrana , Mutação , Peroxidases/genética , Proantocianidinas , Sementes/genética
13.
Ann Bot ; 125(1): 79-91, 2020 01 08.
Artigo em Inglês | MEDLINE | ID: mdl-31504131

RESUMO

BACKGROUND AND AIMS: Prior work has examined cuticle function, composition and ultrastructure in many plant species, but much remains to be learned about how these features are related. This study aims to elucidate relationships between these features via analysis of cuticle development in adult maize (Zea mays L.) leaves, while also providing the most comprehensive investigation to date of the composition and ultrastructure of adult leaf cuticles in this important crop plant. METHODS: We examined water permeability, wax and cutin composition via gas chromatography, and ultrastructure via transmission electron microscopy, along the developmental gradient of partially expanded adult maize leaves, and analysed the relationships between these features. KEY RESULTS: The water barrier property of the adult maize leaf cuticle is acquired at the cessation of cell expansion. Wax types and chain lengths accumulate asynchronously over the course of development, while overall wax load does not vary. Cutin begins to accumulate prior to establishment of the water barrier and continues thereafter. Ultrastructurally, pavement cell cuticles consist of an epicuticular layer, and a thin cuticle proper that acquires an inner, osmiophilic layer during development. CONCLUSIONS: Cuticular waxes of the adult maize leaf are dominated by alkanes and alkyl esters. Unexpectedly, these are localized mainly in the epicuticular layer. Establishment of the water barrier during development coincides with a switch from alkanes to esters as the major wax type, and the emergence of an osmiophilic (likely cutin-rich) layer of the cuticle proper. Thus, alkyl esters and the deposition of the cutin polyester are implicated as key components of the water barrier property of adult maize leaf cuticles.


Assuntos
Água , Zea mays , Epiderme Vegetal , Folhas de Planta , Ceras
14.
Plant Cell Physiol ; 60(5): 1041-1054, 2019 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-30715495

RESUMO

Long-chain acyl-CoA synthetases (LACSs) play diverse and essential roles in lipid metabolism. The genomes of model eukaryotic organisms encode multiple LACS genes, and the substrate specificities of LACS homologs often overlap substantially. Homologous LACSs tend to differ in their expression patterns, localizations, and, by extension, the metabolic pathways to which they contribute. The Arabidopsis genome encodes a family of nine LACS genes, which have been characterized largely by reverse genetic analysis of mutant phenotypes. Because of redundancy, distinguishing the contributions of some Arabidopsis LACS genes has been challenging. Here, we have attempted to clarify the functions of LACSs that functionally overlap by synopsizing the results of previous work, isolating a suite of higher-order mutants that were previously lacking, and analyzing oil, wax, cutin, cuticle permeability, fertility and growth phenotypes. LACS1, LACS2, LACS4, LACS8 and LACS9 all affect cuticular lipid metabolism, but have different precise roles. Seed set, seed weight and storage oil amounts of higher-order lacs1, lacs2, lacs4, lacs8 and lacs9 mutants vary greatly, with these traits subject to different effects of fertility and oil synthesis defects. LACS4, LACS8 and LACS9 have partially redundant roles in development, as lacs4 lacs8 and lacs4 lacs9 double mutants are dwarf. lacs4 lacs8 lacs9 triple mutants were not recovered, and are assumed to be non-viable. Together, these results sketch a complex network of functions and functional interactions within the Arabidopsis LACS gene family.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Coenzima A Ligases/metabolismo , Arabidopsis/fisiologia , Proteínas de Arabidopsis/genética , Coenzima A Ligases/genética , Regulação da Expressão Gênica de Plantas , Metabolismo dos Lipídeos/genética , Metabolismo dos Lipídeos/fisiologia , Óleos de Plantas/metabolismo , Sementes/genética , Sementes/metabolismo
15.
Proc Natl Acad Sci U S A ; 113(25): 6997-7002, 2016 06 21.
Artigo em Inglês | MEDLINE | ID: mdl-27274062

RESUMO

Physical dormancy of seed is an adaptive trait that widely exists in higher plants. This kind of dormancy is caused by a water-impermeable layer that blocks water and oxygen from the surrounding environment and keeps embryos in a viable status for a long time. Most of the work on hardseededness has focused on morphological structure and phenolic content of seed coat. The molecular mechanism underlying physical dormancy remains largely elusive. By screening a large number of Tnt1 retrotransposon-tagged Medicago truncatula lines, we identified nondormant seed mutants from this model legume species. Unlike wild-type hard seeds exhibiting physical dormancy, the mature mutant seeds imbibed water quickly and germinated easily, without the need for scarification. Microscopic observations of cross sections showed that the mutant phenotype was caused by a dysfunctional palisade cuticle layer in the seed coat. Chemical analysis found differences in lipid monomer composition between the wild-type and mutant seed coats. Genetic and molecular analyses revealed that a class II KNOTTED-like homeobox (KNOXII) gene, KNOX4, was responsible for the loss of physical dormancy in the seeds of the mutants. Microarray and chromatin immunoprecipitation analyses identified CYP86A, a gene associated with cutin biosynthesis, as one of the downstream target genes of KNOX4 This study elucidated a novel molecular mechanism of physical dormancy and revealed a new role of class II KNOX genes. Furthermore, KNOX4-like genes exist widely in seed plants but are lacking in nonseed species, indicating that KNOX4 may have diverged from the other KNOXII genes during the evolution of seed plants.


Assuntos
Genes Homeobox , Genes de Plantas , Medicago/genética , Dormência de Plantas/genética , Sementes , Regulação da Expressão Gênica de Plantas , Medicago/embriologia , Mutação
16.
Plant Cell ; 26(9): 3569-88, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25217507

RESUMO

Effective regulation of water balance in plants requires localized extracellular barriers that control water and solute movement. We describe a clade of five Arabidopsis thaliana ABCG half-transporters that are required for synthesis of an effective suberin barrier in roots and seed coats (ABCG2, ABCG6, and ABCG20) and for synthesis of an intact pollen wall (ABCG1 and ABCG16). Seed coats of abcg2 abcg6 abcg20 triple mutant plants had increased permeability to tetrazolium red and decreased suberin content. The root system of triple mutant plants was more permeable to water and salts in a zone complementary to that affected by the Casparian strip. Suberin of mutant roots and seed coats had distorted lamellar structure and reduced proportions of aliphatic components. Root wax from the mutant was deficient in alkylhydroxycinnamate esters. These mutant plants also had few lateral roots and precocious secondary growth in primary roots. abcg1 abcg16 double mutants defective in the other two members of the clade had pollen with defects in the nexine layer of the tapetum-derived exine pollen wall and in the pollen-derived intine layer. Mutant pollen collapsed at the time of anther desiccation. These mutants reveal transport requirements for barrier synthesis as well as physiological and developmental consequences of barrier deficiency.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Parede Celular/metabolismo , Espaço Extracelular/metabolismo , Lipídeos/biossíntese , Pólen/citologia , Pólen/metabolismo , Arabidopsis/genética , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/ultraestrutura , Proteínas de Arabidopsis/genética , Vias Biossintéticas/genética , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Glucuronidase/metabolismo , Proteínas de Membrana Transportadoras/genética , Proteínas de Membrana Transportadoras/metabolismo , Mutação/genética , Permeabilidade , Fenótipo , Raízes de Plantas/metabolismo , Pólen/ultraestrutura , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Sementes/metabolismo , Ceras/metabolismo
17.
Development ; 140(10): 2181-9, 2013 May.
Artigo em Inglês | MEDLINE | ID: mdl-23633512

RESUMO

A number of transcription factors that are expressed within most, if not all, embryonic neuroblast (NB) lineages participate in neural subtype specification. Some have been extensively studied in several NB lineages (e.g. components of the temporal gene cascade) whereas others only within specific NB lineages. To what extent they function in other lineages remains unknown. Klumpfuss (Klu), the Drosophila ortholog of the mammalian Wilms tumor 1 (WT1) protein, is one such transcription factor. Studies in the NB4-2 lineage have suggested that Klu functions to ensure that the two ganglion mother cells (GMCs) in this embryonic NB lineage acquire different fates. Owing to limited lineage marker availability, these observations were made only for the NB4-2 lineage. Recent findings reveal that Klu is necessary for larval neuroblast growth and self-renewal. We have extended the study of Klu to the well-known embryonic NB5-6T lineage and describe a novel role for Klu in the Drosophila embryonic CNS. Our results demonstrate that Klu is expressed specifically in the postmitotic Ap4/FMRFa neuron, promoting its differentiation through the initiation of BMP signaling. Our findings indicate a pleiotropic function of Klu in Ap cluster specification in general and particularly in Ap4 neuron differentiation, indicating that Klu is a multitasking transcription factor. Finally, our studies indicate that a transitory downregulation of klu is crucial for the specification of the Ap4/FMRFa neuron. Similar to WT1, klu seems to have either self-renewal or differentiation-promoting functions, depending on the developmental context.


Assuntos
Proteínas Morfogenéticas Ósseas/metabolismo , Proteínas de Ligação a DNA/metabolismo , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/metabolismo , FMRFamida/metabolismo , Regulação da Expressão Gênica , Fatores de Transcrição/metabolismo , Fator de Crescimento Transformador beta/metabolismo , Animais , Diferenciação Celular , Linhagem da Célula , Análise por Conglomerados , Regulação para Baixo , Regulação da Expressão Gênica no Desenvolvimento , Proteínas de Fluorescência Verde/metabolismo , Imuno-Histoquímica , Microscopia Confocal , Neurônios/metabolismo , Transdução de Sinais
18.
Plant J ; 80(2): 216-29, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25060192

RESUMO

Suberin is a lipid and phenolic cell wall heteropolymer found in the roots and other organs of all vascular plants. Suberin plays a critical role in plant water relations and in protecting plants from biotic and abiotic stresses. Here we describe a transcription factor, AtMYB41 (At4g28110), that can activate the steps necessary for aliphatic suberin synthesis and deposition of cell wall-associated suberin-like lamellae in both Arabidopsis thaliana and Nicotiana benthamiana. Overexpression of AtMYB41 increased the abundance of suberin biosynthetic gene transcripts by orders of magnitude and resulted in the accumulation of up to 22 times more suberin-type than cutin-type aliphatic monomers in leaves. Overexpression of AtMYB41 also resulted in elevated amounts of monolignols in leaves and an increase in the accumulation of phenylpropanoid and lignin biosynthetic gene transcripts. Surprisingly, ultrastructural data indicated that overexpression led to the formation of suberin-like lamellae in both epidermal and mesophyll cells of leaves. We further implicate AtMYB41 in the production of aliphatic suberin under abiotic stress conditions. These results provide insight into the molecular-genetic mechanisms of the biosynthesis and deposition of a ubiquitous cell wall-associated plant structure and will serve as a basis for discovering the transcriptional network behind one of the most abundant lipid-based polymers in nature.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Lipídeos/biossíntese , Fatores de Transcrição/metabolismo , Arabidopsis/genética , Proteínas de Arabidopsis/genética , RNA Mensageiro/genética , Nicotiana/metabolismo , Fatores de Transcrição/genética
19.
Plant Cell Rep ; 34(4): 587-601, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25510356

RESUMO

Terrestrial plants have evolved specific adaptations to preserve water and protect themselves from their environment. Such adaptations range from secondary metabolites and specialized structures that conduct water and nutrients, to cell wall modifications (i.e., cuticle and suberin) that prevent dehydration and provide a physical barrier to pathogens. Both the plant cuticle and suberized cell walls contain a lipid polymer framework embedded with waxes, and constitute a promising target for controlled genetic modification to improve desirable agronomic traits. Recent advances in genomic and molecular techniques coupled with the development of robust analytical methods have accelerated progress in comprehending these intractable lipid polymers. Gene products characterized in the wax, cutin and suberin pathways include a subset of HXXXD/BAHD family enzymes that catalyze acyl transfer reactions between CoA-activated hydroxycinnamic acid derivatives and hydroxylated aliphatics. This review highlights our current understanding of HXXXD/BAHD acyltransferases in extracellular lipid biosynthesis and discusses the chemical, ultrastructural and physiological ramifications of impairing the expression of BAHD acyltransferase-encoding genes related to cutin and suberin synthesis.


Assuntos
Aciltransferases/química , Aciltransferases/metabolismo , Espaço Extracelular/metabolismo , Lipídeos/biossíntese , Motivos de Aminoácidos , Transporte Biológico , Lipídeos/química , Mutação/genética
20.
Cult Health Sex ; 17(6): 682-99, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25567318

RESUMO

Data are presented on young people's sexual victimisation and perpetration from 10 European countries (Austria, Belgium, Cyprus, Greece, Lithuania, the Netherlands, Poland, Portugal, Slovakia and Spain) using a shared measurement tool (N = 3480 participants, aged between 18 and 27 years). Between 19.7 and 52.2% of female and between 10.1 and 55.8% of male respondents reported having experienced at least one incident of sexual victimisation since the age of consent. In two countries, victimisation rates were significantly higher for men than for women. Between 5.5 and 48.7% of male and 2.6 and 14.8% of female participants reported having engaged in a least one act of sexual aggression perpetration, with higher rates for men than for women in all countries. Victimisation rates correlated negatively with sexual assertiveness and positively with alcohol use in sexual encounters. Perpetration rates correlated positively with attitudes condoning physical dating violence and with alcohol use in men, and negatively with sexual assertiveness in women. At the country level, lower gender equality in economic power and in the work domain was related to higher male perpetration rates. Lower gender equality in political power and higher sexual assertiveness in women relative to men were linked to higher male victimisation rates.


Assuntos
Consumo de Bebidas Alcoólicas/epidemiologia , Atitude , Vítimas de Crime/estatística & dados numéricos , Criminosos/estatística & dados numéricos , Violência por Parceiro Íntimo/estatística & dados numéricos , Delitos Sexuais/estatística & dados numéricos , Adolescente , Adulto , Agressão , Áustria/epidemiologia , Bélgica/epidemiologia , Chipre/epidemiologia , Economia , Feminino , Grécia/epidemiologia , Humanos , Lituânia/epidemiologia , Masculino , Análise Multinível , Países Baixos/epidemiologia , Polônia/epidemiologia , Política , Portugal/epidemiologia , Prevalência , Fatores de Risco , Sexismo , Eslováquia/epidemiologia , Espanha/epidemiologia , Inquéritos e Questionários , Adulto Jovem
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA