Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 46
Filtrar
1.
BMJ Open ; 14(7): e086797, 2024 Jul 04.
Artículo en Inglés | MEDLINE | ID: mdl-38964790

RESUMEN

INTRODUCTION: Quality sleep is essential to our health and well-being. Summertime temperatures in the bedrooms of homes in temperate climates are increasing, especially in city apartments. There is very little empirical evidence of the effect of temperature on sleep when people are sleeping in their own bedroom. The Homes Heat Health project seeks to develop a measurable definition of temperature-related sleep disturbance and the effects on health, and so produce a credible criterion for identifying overheating in new and existing homes. METHODS AND ANALYSIS: A cohort of at least 95 people that live in London apartments and who are free of significant personal and health factors that could affect sleep are being recruited for an ongoing observational cohort study. A baseline questionnaire determines their customary sleep patterns and health. The geometrical form and thermal characteristics of their apartments is being recorded along with temperature, relative humidity and in some apartments CO2 levels, throughout one summer. Actigraphy records nightly sleep disturbance and every morning an app-based diary captures perceived sleep quality. Questionnaires following spells of hot weather capture changes in sleep pattern, sleep quality, and consequential health and well-being. ETHICS AND DISSEMINATION: The study protocol was approved by the Loughborough University ethics committee. The participants will receive both verbal and written information explaining the purpose of the study, what is expected of them, the incentives for participating and the feedback that will be provided. The results will be reported bi-annually to a project advisory board. Presentations will be made at conferences and the methods, intermediary and final results, in academic journals. Informing government bodies, professional organisations, construction industry representatives and housing providers is of particular importance.


Asunto(s)
Calor , Vivienda , Estaciones del Año , Calidad del Sueño , Humanos , Calor/efectos adversos , Londres , Encuestas y Cuestionarios , Estudios de Cohortes , Actigrafía , Femenino , Masculino , Trastornos del Sueño-Vigilia/epidemiología , Proyectos de Investigación , Humedad
2.
Plant Biotechnol J ; 22(5): 1372-1386, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38263872

RESUMEN

Fertile pollen is critical for the survival, fitness, and dispersal of flowering plants, and directly contributes to crop productivity. Extensive mutational screening studies have been carried out to dissect the genetic regulatory network determining pollen fertility, but we still lack fundamental knowledge about whether and how pollen fertility is controlled in natural populations. We used a genome-wide association study (GWAS) to show that ZmGEN1A and ZmMSH7, two DNA repair-related genes, confer natural variation in maize pollen fertility. Mutants defective in these genes exhibited abnormalities in meiotic or post-meiotic DNA repair, leading to reduced pollen fertility. More importantly, ZmMSH7 showed evidence of selection during maize domestication, and its disruption resulted in a substantial increase in grain yield for both inbred and hybrid. Overall, our study describes the first systematic examination of natural genetic effects on pollen fertility in plants, providing valuable genetic resources for optimizing male fertility. In addition, we find that ZmMSH7 represents a candidate for improvement of grain yield.


Asunto(s)
Estudio de Asociación del Genoma Completo , Zea mays , Zea mays/genética , Redes Reguladoras de Genes , Polen/genética , Fertilidad/genética , Grano Comestible/genética
3.
Plant Biotechnol J ; 22(1): 200-215, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-37752705

RESUMEN

Grain size is one of the important traits in wheat breeding programs aimed at improving yield, and cytokinins, mainly involved in cell division, have a positive impact on grain size. Here, we identified a novel wheat gene TaMADS-GS encoding type I MADS-box transcription factor, which regulates the cytokinins signalling pathway during early stages of grain development to modulate grain size and weight in wheat. TaMADS-GS is exclusively expressed in grains at early stage of seed development and its knockout leads to delayed endosperm cellularization, smaller grain size and lower grain weight. TaMADS-GS protein interacts with the Polycomb Repressive Complex 2 (PRC2) and leads to repression of genes encoding cytokinin oxidase/dehydrogenases (CKXs) stimulating cytokinins inactivation by mediating accumulation of the histone H3 trimethylation at lysine 27 (H3K27me3). Through the screening of a large wheat germplasm collection, an elite allele of the TaMADS-GS exhibits higher ability to repress expression of genes inactivating cytokinins and a positive correlation with grain size and weight, thus representing a novel marker for breeding programs in wheat. Overall, these findings support the relevance of TaMADS-GS as a key regulator of wheat grain size and weight.


Asunto(s)
Endospermo , Factores de Transcripción , Factores de Transcripción/genética , Endospermo/metabolismo , Triticum/metabolismo , Fitomejoramiento , Grano Comestible , Citocininas/metabolismo , Regulación de la Expresión Génica de las Plantas/genética
4.
J Integr Plant Biol ; 65(12): 2587-2603, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-37846823

RESUMEN

Interploidy hybridization between hexaploid and tetraploid genotypes occurred repeatedly during genomic introgression events throughout wheat evolution, and is commonly employed in wheat breeding programs. Hexaploid wheat usually serves as maternal parent because the reciprocal cross generates progeny with severe defects and poor seed germination, but the underlying mechanism is poorly understood. Here, we performed detailed analysis of phenotypic variation in endosperm between two interploidy reciprocal crosses arising from tetraploid (Triticum durum, AABB) and hexaploid wheat (Triticum aestivum, AABBDD). In the paternal- versus the maternal-excess cross, the timing of endosperm cellularization was delayed and starch granule accumulation in the endosperm was repressed, causing reduced germination percentage. The expression profiles of genes involved in nutrient metabolism differed strongly between these endosperm types. Furthermore, expression patterns of parental alleles were dramatically disturbed in interploidy versus intraploidy crosses, leading to increased number of imprinted genes. The endosperm-specific TaLFL2 showed a paternally imprinted expression pattern in interploidy crosses partially due to allele-specific DNA methylation. Paternal TaLFL2 binds to and represses a nutrient accumulation regulator TaNAC019, leading to reduced storage protein and starch accumulation during endosperm development in paternal-excess cross, as confirmed by interploidy crosses between tetraploid wild-type and clustered regularly interspaced palindromic repeats (CRISPR) - CRISPR-associated protein 9 generated hexaploid mutants. These findings reveal a contribution of genomic imprinting to paternal-excess interploidy hybridization barriers during wheat evolution history and explains why experienced breeders preferentially exploit maternal-excess interploidy crosses in wheat breeding programs.


Asunto(s)
Factores de Transcripción , Triticum , Factores de Transcripción/metabolismo , Triticum/genética , Semillas/genética , Tetraploidía , Fitomejoramiento , Aislamiento Reproductivo , Cruzamientos Genéticos , Endospermo/genética , Almidón/metabolismo
5.
New Phytol ; 239(1): 87-101, 2023 07.
Artículo en Inglés | MEDLINE | ID: mdl-36617723

RESUMEN

Gluten is composed of glutenins and gliadins and determines the viscoelastic properties of dough and end-use quality in wheat (Triticum aestivum L.). Gliadins are important for wheat end-use traits, but the contribution of individual gliadin genes is unclear, since gliadins are encoded by a complex, multigenic family, including many pseudogenes. We used CRISPR/Cas9-mediated gene editing and map-based cloning to investigate the contribution of the γ-gliadin genes annotated in the wheat cultivar 'Fielder', showing that Gli-γ1-1D and Gli-γ2-1B account for most of the γ-gliadin accumulation. The impaired activity of only two γ-gliadin genes in knockout mutants improved end-use quality and reduced gluten epitopes associated with celiac disease (CD). Furthermore, we identified an elite haplotype of Gli-γ1-1D linked to higher end-use quality in a wheat germplasm collection and developed a molecular marker for this allele for marker-assisted selection. Our findings provide information and tools for biotechnology-based and classical breeding programs aimed at improving wheat end-use quality.


Asunto(s)
Gliadina , Triticum , Gliadina/genética , Triticum/genética , Alelos , Fitomejoramiento , Glútenes/genética
6.
New Phytol ; 237(2): 585-600, 2023 01.
Artículo en Inglés | MEDLINE | ID: mdl-36266961

RESUMEN

Extensive mutational screening studies have documented genes regulating anther and pollen development. Knowledge concerning how formation of male germinal cell is arithmetically controlled in natural populations, under different environmental conditions, is lacking. We counted pollen number within a single anther and a maize-teosinte BC2 S3 recombinant inbred line population to identify ZmCCT10 as a major determinant of pollen number variation. ZmCCT10 was originally identified as a photoperiod-sensitive negative regulator of flowering. ZmCCT10 inactivation, after transposon insertion within its promoter, is proposed to have accelerated maize spread toward higher latitudes, thus allowing temperate maize to flower under long-day conditions. We showed that the active ZmCCT10 allele decreased pollen formation. As different active and inactive ZmCCT10 alleles have been found in natural maize populations, this represents the first report of a gene controlling pollen number in a crop natural population. These findings suggest that higher pollen number, which provides a competitive advantage in open-pollinated populations, may have been one of the major driving forces for the selection of an inactive ZmCCT10 allele during tropical maize domestication. We provide evidence that ZmCCT10 has opposite effects on cell proliferation of archesporial and tapetum cells and it modulates expression of key regulators during early anther development.


Asunto(s)
Fotoperiodo , Zea mays , Zea mays/genética , Flores/fisiología
7.
8.
New Phytol ; 236(1): 146-164, 2022 10.
Artículo en Inglés | MEDLINE | ID: mdl-35714031

RESUMEN

Along with increasing demands for high yield, elite processing quality and improved nutrient value in wheat, concerns have emerged around the effects of gluten in wheat-based foods on human health. However, knowledge of the mechanisms regulating gluten accumulation remains largely unexplored. Here we report the identification and characterization of a wheat low gluten protein 1 (lgp1) mutant that shows extremely low levels of gliadins and glutenins. The lgp1 mutation in a single γ-gliadin gene causes defective signal peptide cleavage, resulting in the accumulation of an excessive amount of unprocessed γ-gliadin and a reduced level of gluten, which alters the endoplasmic reticulum (ER) structure, forms the autophagosome-like structures, leads to the delivery of seed storage proteins to the extracellular space and causes a reduction in starch biosynthesis. Physiologically, these effects trigger ER stress and cell death. This study unravels a unique mechanism that unprocessed γ-gliadin reduces gluten accumulation associated with ER stress and elevated cell death in wheat. Moreover, the reduced gluten level in the lgp1 mutant makes it a good candidate for specific diets for patients with diabetes or kidney diease.


Asunto(s)
Gliadina , Triticum , Muerte Celular , Estrés del Retículo Endoplásmico , Gliadina/química , Gliadina/genética , Gliadina/metabolismo , Glútenes/química , Glútenes/genética , Humanos , Triticum/metabolismo
9.
Genome ; : 1-12, 2021 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-34597524

RESUMEN

Small RNAs (sRNAs) are epigenetic regulators of eukaryotic genes and transposable elements (TEs). Diverse sRNA expression patterns exist within a species, but how this diversity arises is not well understood. To provide a window into the dynamics of maize sRNA patterning, sRNA and mRNA transcriptomes were examined in two related Zea mays recombinant inbred lines (RILs) and their inbred parents. Analysis of these RILs revealed that most clusters of sRNA expression retained the parental sRNA expression level. However, expression states that differ from the parental allele were also observed, predominantly reflecting decreases in sRNA expression. When RIL sRNA expression differed from the parental allele, the new state was frequently similar between the two RILs, and similar to the expression state found at the allele in the other parent. Novel sRNA expression patterns, distinct from those of either parent, were rare. Additionally, examination of sRNA expression over TEs revealed one TE family, Gyma, which showed consistent enrichment for RIL sRNA expression differences compared to those found in parental alleles. These findings provide insights into how sRNA silencing might evolve over generations and suggest that further investigation into the molecular nature of sRNA trans regulators is warranted.

10.
Clin Chim Acta ; 521: 1-8, 2021 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-34111419

RESUMEN

BACKGROUND: The iPTH upper reference limit (URL) reported by our laboratory provider (Abbott Laboratories) at Tor Vergata University Hospital was evaluated by internal verification procedures as not representative of our population and resulting as underestimated. In this study, a new reference interval has been investigated and established by comparing a direct and an indirect method based on a statistical reduction from results stored in the laboratory database. METHODS: For reference interval calculation from the healthy population, we analyzed a cohort of 100 blood donors (84% males and 16% females) screened with no bone-related and malabsorption diseases. We analyzed a cohort of 495 patients retrieved from more than 800 iPTH results by excluding subjects with pathological measurement for calcium, phosphorus, and creatinine for the reference interval evaluation. Patients with vitamin D results were included in the analysis. Vitamin D sufficiency status during the period from January to September 2020 was also evaluated by investigating 3,050 patients. RESULTS: The iPTH reference interval of a healthy blood donor population was measured as 25.2-109.1 pg/mL (2.7-11.6 pmol/L) at 2.5 and 97.5 distribution percentile. The iPTH reference interval from data stored in the laboratory database was 19.3-112.5 pg/mL (2.0-11.9 pmol/L). Furthermore, 60% of the whole population had prevalently insufficient vitamin D concentration (<30 ng/dL; <75 nmol/L). The impact of vitamin D concentration on the iPTH reference interval was measured for insufficient vitamin D (<30 ng/dL; <75 nmol/L) as 15.2-127.7 pg/mL (1.6-13.5 pmol/L), desirable vitamin D (30-40 ng/ml; 75-100 nmol/L) as 25.6-105 pg/mL (2.7-10.7 pmol/L) and optimal vitamin D (>40 ng/ml; >100 nmol/L) as 26.2-89.2 pg/mL (2.8-9.4 pmol/L), respectively. CONCLUSIONS: The URL reported in manufacturer datasheets likely refers to a normal population with non-pathological vitamin D levels. On the contrary, the considered population was mostly vitamin D insufficient, resulting in a URL shift. On this basis, we suggest describing in medical reports the iPTH range for vitamin D deficiency for diagnosis of primary hyperparathyroidism even when a specific vitamin D request is lacking. On the other hand, reporting optimal vitamin D-based iPTH reference interval could be clinically relevant in supplemented patients as a marker of treatment efficacy.


Asunto(s)
Deficiencia de Vitamina D , Vitamina D , Calcio , Femenino , Humanos , Masculino , Hormona Paratiroidea , Prevalencia
11.
Genome ; 64(12): 1091-1098, 2021 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-34192470

RESUMEN

Near-isogenic lines (NILs) are classical genetic tools used to dissect the actions of an allele when placed in a uniform genetic background. Although the goal of NIL creation is to examine the effects of a single allele in isolation, DNA linked to the allele is invariably retained and can confound any allele-specific effects. In addition to genetic variation, highly polymorphic species such as Zea mays will contain introgressed polymorphisms encompassing transposable elements (TEs) and the cis-acting small RNA (sRNA) that represses them. Through transcriptomics, we described the differences in sRNA and TE transcriptional expression between a W22-derived introgression and its homologous B73 region. As anticipated, many differences in sRNA expression were observed. Unexpectedly, however, 24nt sRNA expression over the introgressed region was low overall compared to both the homologous B73 region and the rest of the genome. Across the introgression, low sRNA expression was accompanied by increased TE transcription. Possible explanations for the observed trends in sRNA and TE expression across the introgression region are discussed. These findings support the notion that any introgressed allele is in an epigenetic environment distinct from that found at the allele from the recurrent parent. Additionally, these results suggest that further study of sRNA expression levels during the introgression process is warranted.


Asunto(s)
Elementos Transponibles de ADN , ARN de Planta/genética , Zea mays , Alelos , Elementos Transponibles de ADN/genética , Zea mays/genética
12.
Plant Cell ; 33(3): 603-622, 2021 05 05.
Artículo en Inglés | MEDLINE | ID: mdl-33955492

RESUMEN

In wheat (Triticum aestivum L.), breeding efforts have focused intensively on improving grain yield and quality. For quality, the content and composition of seed storage proteins (SSPs) determine the elasticity of wheat dough and flour processing quality. Moreover, starch levels in seeds are associated with yield. However, little is known about the mechanisms that coordinate SSP and starch accumulation in wheat. In this study, we explored the role of the endosperm-specific NAC transcription factor TaNAC019 in coordinating SSP and starch accumulation. TaNAC019 binds to the promoters of TaGlu-1 loci, encoding high molecular weight glutenin (HMW-GS), and of starch metabolism genes. Triple knock-out mutants of all three TaNAC019 homoeologs exhibited reduced transcript levels for all SSP types and genes involved in starch metabolism, leading to lower gluten and starch contents, and in flour processing quality parameters. TaNAC019 directly activated the expression of HMW-GS genes by binding to a specific motif in their promoters and interacting with the TaGlu-1 regulator TaGAMyb. TaNAC019 also indirectly regulated the expression of TaSPA, an ortholog of maize Opaque2 that activates SSP accumulation. Therefore, TaNAC019 regulation of starch- and SSP-related genes has key roles in wheat grain quality. Finally, we identified an elite allele (TaNAC019-BI) associated with flour processing quality, providing a candidate gene for breeding wheat with improved quality.


Asunto(s)
Endospermo/metabolismo , Proteínas de Plantas/metabolismo , Almidón/metabolismo , Factores de Transcripción/metabolismo , Alelos , Endospermo/genética , Glútenes/genética , Glútenes/metabolismo , Proteínas de Plantas/genética , Almidón/genética , Factores de Transcripción/genética , Triticum/genética , Triticum/metabolismo
13.
Lancet Respir Med ; 9(2): 159-166, 2021 02.
Artículo en Inglés | MEDLINE | ID: mdl-32687801

RESUMEN

BACKGROUND: The importance of lung recruitment before surfactant administration has been shown in animal studies. Well designed trials in preterm infants are absent. We aimed to examine whether the application of a recruitment manoeuvre just before surfactant administration, followed by rapid extubation (intubate-recruit-surfactant-extubate [IN-REC-SUR-E]), decreased the need for mechanical ventilation during the first 72 h of life compared with no recruitment manoeuvre (ie, intubate-surfactant-extubate [IN-SUR-E]). METHODS: We did a randomised, unblinded, controlled trial in 35 tertiary neonatal intensive care units in Italy. Spontaneously breathing extremely preterm neonates (24 + 0 to 27 + 6 weeks' gestation) reaching failure criteria for continuous positive airway pressure within the first 24 h of life were randomly assigned (1:1) with a minimisation algorithm to IN-REC-SUR-E or IN-SUR-E using an interactive web-based electronic system, stratified by clinical site and gestational age. The primary outcome was the need for mechanical ventilation in the first 72 h of life. Analyses were done in intention-to-treat and per-protocol populations, with a log-binomial regression model correcting for stratification factors to estimate adjusted relative risk (RR). This study is registered with ClinicalTrials.gov, NCT02482766. FINDINGS: Of 556 infants assessed for eligibility, 218 infants were recruited from Nov 12, 2015, to Sept 23, 2018, and included in the intention-to-treat analysis. The requirement for mechanical ventilation during the first 72 h of life was reduced in the IN-REC-SUR-E group (43 [40%] of 107) compared with the IN-SUR-E group (60 [54%] of 111; adjusted RR 0·75, 95% CI 0·57-0·98; p=0·037), with a number needed to treat of 7·2 (95% CI 3·7-135·0). The addition of the recruitment manoeuvre did not adversely affect the safety outcomes of in-hospital mortality (19 [19%] of 101 in the IN-REC-SUR-E group vs 37 [33%] of 111 in the IN-SUR-E group), pneumothorax (four [4%] of 101 vs seven [6%] of 111), or grade 3 or worse intraventricular haemorrhage (12 [12%] of 101 vs 17 [15%] of 111). INTERPRETATION: A lung recruitment manoeuvre just before surfactant administration improved the efficacy of surfactant treatment in extremely preterm neonates compared with the standard IN-SUR-E technique, without increasing the risk of adverse neonatal outcomes. The reduced need for mechanical ventilation during the first 72 h of life might facilitate implementation of a non-invasive respiratory support strategy. FUNDING: None.


Asunto(s)
Extubación Traqueal/métodos , Cuidados Críticos/métodos , Intubación Intratraqueal/métodos , Surfactantes Pulmonares/uso terapéutico , Síndrome de Dificultad Respiratoria del Recién Nacido/terapia , Femenino , Humanos , Recien Nacido Extremadamente Prematuro , Recién Nacido , Unidades de Cuidado Intensivo Neonatal , Italia , Pulmón/fisiopatología , Masculino , Respiración Artificial/estadística & datos numéricos , Resultado del Tratamiento
15.
Plant Cell Environ ; 43(1): 55-75, 2020 01.
Artículo en Inglés | MEDLINE | ID: mdl-31677283

RESUMEN

During their lifespan, plants respond to a multitude of stressful factors. Dynamic changes in chromatin and concomitant transcriptional variations control stress response and adaptation, with epigenetic memory mechanisms integrating environmental conditions and appropriate developmental programs over the time. Here we analyzed transcriptome and genome-wide histone modifications of maize plants subjected to a mild and prolonged drought stress just before the flowering transition. Stress was followed by a complete recovery period to evaluate drought memory mechanisms. Three categories of stress-memory genes were identified: i) "transcriptional memory" genes, with stable transcriptional changes persisting after the recovery; ii) "epigenetic memory candidate" genes in which stress-induced chromatin changes persist longer than the stimulus, in absence of transcriptional changes; iii) "delayed memory" genes, not immediately affected by the stress, but perceiving and storing stress signal for a delayed response. This last memory mechanism is described for the first time in drought response. In addition, applied drought stress altered floral patterning, possibly by affecting expression and chromatin of flowering regulatory genes. Altogether, we provided a genome-wide map of the coordination between genes and chromatin marks utilized by plants to adapt to a stressful environment, describing how this serves as a backbone for setting stress memory.


Asunto(s)
Aclimatación , Adaptación Fisiológica/genética , Epigénesis Genética , Flores/fisiología , Estrés Fisiológico/genética , Zea mays/fisiología , Cromatina/metabolismo , Mapeo Cromosómico , Cromosomas de las Plantas/fisiología , Sequías , Epigenómica , Perfilación de la Expresión Génica , Regulación de la Expresión Génica de las Plantas , Ontología de Genes , Código de Histonas , Histonas/genética , Histonas/metabolismo , Inmunoprecipitación , Desarrollo de la Planta/genética , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Análisis de Componente Principal , Análisis de Secuencia de ARN , Transcriptoma
16.
Plant Physiol ; 181(1): 179-194, 2019 09.
Artículo en Inglés | MEDLINE | ID: mdl-31209125

RESUMEN

In grass crops, leaf angle is determined by development of the lamina joint, the tissue connecting the leaf blade and sheath, and is closely related to crop architecture and yield. In this study, we identified a mutant generated by fast neutron radiation that exhibited an erect leaf phenotype caused by defects in lamina joint development. Map-based cloning revealed that the gene TaSPL8, encoding a SQUAMOSA PROMOTER BINDING-LIKE (SPL) protein, is deleted in this mutant. TaSPL8 knock-out mutants exhibit erect leaves due to loss of the lamina joint, compact architecture, and increased spike number especially in high planting density, suggesting similarity with its LIGULESS1 homologs in maize (Zea mays) and rice (Oryza sativa). Hence, LG1 could be a robust target for plant architecture improvement in grass species. Common wheat (Triticum aestivum, 2n = 6× = 42; BBAADD) is an allohexaploid containing A, B, and D subgenomes and the homeologous gene of TaSPL8 from the D subgenome contributes to the length of the lamina joint to a greater extent than that from the A and B subgenomes. Comparison of the transcriptome between the Taspl8 mutant and the wild type revealed that TaSPL8 is involved in the activation of genes related to auxin and brassinosteroid pathways and cell elongation. TaSPL8 binds to the promoters of the AUXIN RESPONSE FACTOR gene and of the brassinosteroid biogenesis gene CYP90D2 and activates their expression. These results indicate that TaSPL8 might regulate lamina joint development through auxin signaling and the brassinosteroid biosynthesis pathway.


Asunto(s)
Brasinoesteroides/metabolismo , Ácidos Indolacéticos/metabolismo , Reguladores del Crecimiento de las Plantas/metabolismo , Proteínas de Plantas/metabolismo , Transcriptoma , Triticum/genética , Regulación de la Expresión Génica de las Plantas , Fenotipo , Hojas de la Planta/genética , Hojas de la Planta/crecimiento & desarrollo , Hojas de la Planta/fisiología , Proteínas de Plantas/genética , Regiones Promotoras Genéticas/genética , Transducción de Señal , Triticum/crecimiento & desarrollo , Triticum/fisiología
17.
J Exp Bot ; 69(12): 2937-2952, 2018 05 25.
Artículo en Inglés | MEDLINE | ID: mdl-29688423

RESUMEN

Temperate maize was domesticated from its tropical ancestor, teosinte. Whereas temperate maize is an autonomous day-neutral plant, teosinte is an obligate short-day plant that requires uninterrupted long nights to induce flowering. Leaf-derived florigenic signals trigger reproductive growth in both teosinte and temperate maize. To study the genetic mechanisms underlying floral inductive pathways in maize and teosinte, mRNA and small RNA genome-wide expression analyses were conducted on leaf tissue from plants that were induced or not induced to flower. Transcriptome profiles reveal common differentially expressed genes during floral induction, but a comparison of candidate flowering time genes indicates that photoperiod and autonomous pathways act independently. Expression differences in teosinte are consistent with the current paradigm for photoperiod-induced flowering, where changes in circadian clock output trigger florigen production. Conversely, differentially expressed genes in temperate maize link carbon partitioning and flowering, but also show altered expression of circadian clock genes that are distinct from those altered upon photoperiodic induction in teosinte. Altered miRNA399 levels in both teosinte and maize suggest a novel common connection between flowering and phosphorus perception. These findings provide insights into the molecular mechanisms underlying a strengthened autonomous pathway that enabled maize growth throughout temperate regions.


Asunto(s)
Flores/crecimiento & desarrollo , Redes Reguladoras de Genes , Fotoperiodo , Proteínas de Plantas/genética , ARN de Planta/genética , Zea mays/genética , Domesticación , Flores/genética , Hojas de la Planta/genética , Hojas de la Planta/crecimiento & desarrollo , Proteínas de Plantas/metabolismo , ARN Mensajero/genética , ARN Mensajero/metabolismo , ARN de Planta/metabolismo , Zea mays/crecimiento & desarrollo
18.
Plant Cell ; 30(4): 796-814, 2018 04.
Artículo en Inglés | MEDLINE | ID: mdl-29567662

RESUMEN

Seed germination is important for grain yield and quality and rapid, near-simultaneous germination helps in cultivation; however, cultivars that germinate too readily can undergo preharvest sprouting (PHS), which causes substantial losses in areas that tend to get rain around harvest time. Moreover, our knowledge of mechanisms regulating seed germination in wheat (Triticum aestivum) remains limited. In this study, we analyzed function of a wheat-specific microRNA 9678 (miR9678), which is specifically expressed in the scutellum of developing and germinating seeds. Overexpression of miR9678 delayed germination and improved resistance to PHS in wheat through reducing bioactive gibberellin (GA) levels; miR9678 silencing enhanced germination rates. We provide evidence that miR9678 targets a long noncoding RNA (WSGAR) and triggers the generation of phased small interfering RNAs that play a role in the delay of seed germination. Finally, we found that abscisic acid (ABA) signaling proteins bind the promoter of miR9678 precursor and activate its expression, indicating that miR9678 affects germination by modulating the GA/ABA signaling.


Asunto(s)
Ácido Abscísico/metabolismo , Giberelinas/metabolismo , MicroARNs/genética , ARN Interferente Pequeño/genética , Transducción de Señal/genética , Triticum/genética , Germinación , Triticum/fisiología
19.
Plant Cell ; 28(3): 629-45, 2016 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-26908760

RESUMEN

Histone deacetylases (HDACs) regulate histone acetylation levels by removing the acetyl group from lysine residues. The maize (Zea mays) HDACHDA101 influences several aspects of development, including kernel size; however, the molecular mechanism by which HDA101 affects kernel development remains unknown. In this study, we find that HDA101 regulates the expression of transfer cell-specific genes, suggesting that their misregulation may be associated with the defects in differentiation of endosperm transfer cells and smaller kernels observed in hda101 mutants. To investigate HDA101 function during the early stages of seed development, we performed genome-wide mapping of HDA101 binding sites. We observed that, like mammalian HDACs, HDA101 mainly targets highly and intermediately expressed genes. Although loss of HDA101 can induce histone hyperacetylation of its direct targets, this often does not involve variation in transcript levels. A small subset of inactive genes that must be negatively regulated during kernel development is also targeted by HDA101 and its loss leads to hyperacetylation and increased expression of these inactive genes. Finally, we report that HDA101 interacts with members of different chromatin remodeling complexes, such as NFC103/MSI1 and SNL1/SIN3-like protein corepressors. Taken together, our results reveal a complex genetic network regulated by HDA101 during seed development and provide insight into the different mechanisms of HDA101-mediated regulation of transcriptionally active and inactive genes.


Asunto(s)
Redes Reguladoras de Genes/efectos de los fármacos , Inhibidores de Histona Desacetilasas/farmacología , Histona Desacetilasas/genética , Histonas/efectos de los fármacos , Semillas/enzimología , Zea mays/enzimología , Mapeo Cromosómico , Regulación de la Expresión Génica de las Plantas/efectos de los fármacos , Histona Desacetilasas/metabolismo , Histonas/genética , Histonas/metabolismo , Proteínas de Plantas/antagonistas & inhibidores , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Semillas/efectos de los fármacos , Semillas/genética , Semillas/crecimiento & desarrollo , Análisis de Secuencia de ARN , Técnicas del Sistema de Dos Híbridos , Zea mays/efectos de los fármacos , Zea mays/genética , Zea mays/crecimiento & desarrollo
20.
Mediterr J Hematol Infect Dis ; 7(1): e2015041, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26075048

RESUMEN

BACKGROUND AND OBJECTIVES: Acute lymphoblastic leukaemia (ALL) carrying t(9;22) or t(4;11) genetic abnormalities represents a very high risk subtype of disease (VHR-ALL). Hematopoietic stem cell transplantation (HSCT) remains the best curative option not only for t(4;11) ALL, but also for t(9;22) ALL in the tyrosin-kinase inhibitors era. In the last years, low molecular level of minimal residual disease (MRD) before HSCT was reported as one of the best favourable indexes for survival in ALL. Here we observed that even these patients can show a favourable outcome if submitted to HSCT with very low MRD. METHODS: We considered 18 consecutive VHR-ALL patients eligible to HSCT. 16 of them were transplanted in first remission, as soon as possible, employing myelo-ablative conditioning regimens. Molecular MRD has been evaluated before and after HSCT. RESULTS: Immediately before HSCT, MRD revealed: complete molecular remission (MRD(neg)) for five patients, and a level <1×10(-3) for seven patients. 100 days after HSCT we had: MRD(neg) for seven patients and a decrease for all the others after HSCT. After the tapering of immunosuppressive drugs, 13 patients reached the MRD(neg) in a median time of 8 months (range 3-16). In the intention to treat analysis, 14/18 patients are alive and disease free at the date of analysis. Overall survival and event free survival is of 78% and 66% respectively, with an average follow-up of 45 months (range 6-84) since HSCT. CONCLUSION: Early transplantation with low MRD level seems to be correlated with a favourable outcome also in VHR-ALL.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...