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1.
J Agric Food Chem ; 67(35): 9697-9704, 2019 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-31403787

RESUMO

In higher plants, seed size is an important parameter and agricultural trait in many aspects of evolutionary fitness. The loss of water-deficiency-induced crop yield is the largest among all natural hazards. Under water-deficient stress, the most prevalent response to terminal stress is to accelerate the early arrest of floral development and, thereby, to accelerate fruit/seed production, which consequently reduces seed size. This phenomenon is well-known, but its molecular mechanism is not well-reviewed and characterized. However, increasing evidence have indicated that water-deficient stress is always coordinated with three genetic signals (i.e., seed size regulators, initial seed size, and fruit number) that decide the final seed size. Here, our review presents new insights into the mechanism underlying cross-talk water-deficient stress signaling with three genetic signals controlling final seed size. These new insights may aid in preliminary screening, identifying novel genetic factors and future design strategies, or breeding to increase crop yield.


Assuntos
Sementes/citologia , Água/metabolismo , Secas , Regulação da Expressão Gênica de Plantas , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Sementes/genética , Sementes/crescimento & desenvolvimento , Sementes/metabolismo , Estresse Fisiológico , Água/análise
2.
Plant Cell Rep ; 38(3): 345-359, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30649573

RESUMO

KEY MESSAGE: FLO15encodes a plastidic glyoxalase I protein, OsGLYI7, which affects compound starch granule formation and starch synthesis in rice endosperm. Starch synthesis in rice (Oryza sativa) endosperm is a sophisticated process, and its underlying molecular machinery still remains to be elucidated. Here, we identified and characterized two allelic rice floury endosperm 15 (flo15) mutants, both with a white-core endosperm. The flo15 grains were characterized by defects in compound starch granule development, along with decreased starch content. Map-based cloning of the flo15 mutants identified mutations in OsGLYI7, which encodes a glyoxalase I (GLYI) involved in methylglyoxal (MG) detoxification. The mutations of FLO15/OsGLYI7 resulted in increased MG content in flo15 developing endosperms. FLO15/OsGLYI7 localizes to the plastids, and the in vitro GLYI activity derived from flo15 was significantly decreased relative to the wild type. Moreover, the expression of starch synthesis-related genes was obviously altered in the flo15 mutants. These findings suggest that FLO15 plays an important role in compound starch granule formation and starch synthesis in rice endosperm.


Assuntos
Endosperma/enzimologia , Regulação da Expressão Gênica de Plantas , Lactoilglutationa Liase/metabolismo , Oryza/enzimologia , Amido/metabolismo , Grânulos Citoplasmáticos/metabolismo , Endosperma/citologia , Endosperma/genética , Genes Reporter , Lactoilglutationa Liase/genética , Mutação , Oryza/citologia , Oryza/genética , Fenótipo , Filogenia , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plastídeos/enzimologia , Sementes/citologia , Sementes/enzimologia , Sementes/genética , Técnicas do Sistema de Duplo-Híbrido
3.
Plant Reprod ; 32(1): 105-111, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30547251

RESUMO

Plant zygotes usually undergo asymmetrical cell division, giving rise to the formation of two daughter cells with distinct developmental cell fate. The small apical cell will develop into the major part of embryo proper, whereas the larger basal cell will divide to form a transient suspensor. Thus, the apical and basal cell lineages are an excellent model to study cell fate determination in relation to zygote polarity. However, the molecular mechanism underlying the differentiation of two distinct cell lineages is not yet understood, possibly due to the technique limitations. Previously, we have established a protocol for isolating apical cell and basal cell for cDNA library construction in tobacco. However, the method for isolating tiny Arabidopsis embryos has long been considered much more difficult. Here, we present a detailed protocol for isolating early Arabidopsis proembryos and separating apical and basal cell lineages of proembryos, which allow us to establish cell lineage-specific transcriptomes of early proembryos.


Assuntos
Arabidopsis/citologia , Linhagem da Célula , Separação Celular/métodos , Células Vegetais , Sementes/citologia , Sementes/genética , Arabidopsis/embriologia , Arabidopsis/genética , Perfilação da Expressão Gênica , RNA de Plantas
4.
Int J Mol Sci ; 19(12)2018 Dec 12.
Artigo em Inglês | MEDLINE | ID: mdl-30545080

RESUMO

Somatic embryos (SE) have potential to rapidly form a whole plant. Generally, SE is thought to be derived from embryogenic calli (EC). However, in maize, not only embryogenic calli (EC, can generate SE) but also nonembryogenic calli (NEC, can't generate SE) can be induced from immature embryos. In order to understand the differences between EC and NEC and the mechanism of EC, which can easily form SE in maize, differential abundance protein species (DAPS) of EC and NEC from the maize inbred line Y423 were identified by using the isobaric tags for relative and absolute quantification (iTRAQ) proteomic technology. We identified 632 DAPS in EC compared with NEC. The results of bioinformatics analysis showed that EC development might be related to accumulation of pyruvate caused by the DAPS detected in some pathways, such as starch and sucrose metabolism, glycolysis/gluconeogenesis, tricarboxylic acid (TCA) cycle, fatty acid metabolism and phenylpropanoid biosynthesis. Based on the differentially accumulated proteins in EC and NEC, a series of DAPS related with pyruvate biosynthesis and suppression of acetyl-CoA might be responsible for the differences between EC and NEC cells. Furthermore, we speculate that the decreased abundance of enzymes/proteins involved in phenylpropanoid biosynthesis pathway in the EC cells results in reducing of lignin substances, which might affect the maize callus morphology.


Assuntos
Endogamia , Marcação por Isótopo/métodos , Proteômica/métodos , Zea mays/embriologia , Zea mays/metabolismo , Biologia Computacional , Regulação da Expressão Gênica de Plantas , Ontologia Genética , Genes de Plantas , Modelos Biológicos , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Sementes/citologia , Transcrição Genética
5.
Protoplasma ; 255(6): 1839-1854, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-29948368

RESUMO

Lycium barbarum L. fruits, referred to as functional food, have long been used in traditional and folk herbal medicine due to their therapeutic properties. The fruit microstructure was analysed using light, scanning and transmission electron microscopes. The distribution of bioactive compounds in drupe tissues was assessed with histochemical and fluorescence assays. The analysis of the microstructure has shown that the fruit is covered by a skin with an amorphous cuticle and a layer of amorphous epicuticular waxes on the surface. The skin is composed of a single-layered epidermis with thickened walls and one layer of hypodermis with slightly thickened periclinal walls. The pericarp cells contain different types of chromoplasts, which most often contained exhibited reticulotubules/fibrils of carotenoid pigments and phytoferritine deposits. The results of the histochemical assays demonstrated that the secondary metabolites with high phytotherapeutic importance were located in all layers of the pericarp and seeds and, specifically, in the drupe exocarp and endocarp. The phytochemicals were represented by polysaccharides (LBP), lipid compounds (carotenoids, essential oils, sesquiterpenes, steroids), polyphenols (tannins and flavonoids), and alkaloids. This study, which is the first report of the microstructure and localisation of bioactive compounds in wolfberries, is a valuable complement of phytochemical analyses and can be helpful for enhancement of the therapeutic effect of the fruit as well as preliminary assessment of the medicinal potential in the search for new pharmaceuticals. Detailed anatomical studies are crucial for exploration of determinants of fruit quality and useful for identification of diagnostic taxonomic traits.


Assuntos
Frutas/citologia , Alimento Funcional , Medicina Herbária , Lycium/citologia , Fluorescência , Frutas/ultraestrutura , Lycium/ultraestrutura , Metabolismo Secundário , Sementes/citologia , Sementes/ultraestrutura
6.
Planta ; 248(2): 369-379, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29737417

RESUMO

MAIN CONCLUSION: In soybean, occurrence of, or tolerance to, seed cracking under low temperatures may be related to the presence or absence, respectively, of proanthocyanidin accumulation in the seed coat dorsal region. Soybean seeds sometimes undergo cracking during low temperatures in summer. In this study, we focused on the occurrence and tolerance mechanisms of low-temperature-induced seed cracking in the sensitive yellow soybean cultivar Yukihomare and the tolerant yellow soybean breeding line Toiku 248. Yukihomare exhibited seed cracking when subjected to a 21-day low-temperature treatment from 10 days after flowering. In yellow soybeans, seed coat pigmentation is inhibited, leading to low proanthocyanidin levels in the seed coat. Proanthocyanidins accumulated on the dorsal side of the seed coat in Yukihomare under the 21-day low-temperature treatment. In addition, a straight seed coat split occurred on the dorsal side at the full-sized seed stage, resulting in seed cracking in this cultivar. Conversely, proanthocyanidin accumulation was suppressed throughout the seed coat in low-temperature-treated Toiku 248. We propose the following mechanism of seed cracking: proanthocyanidin accumulation and subsequent lignin deposition under low temperatures affects the physical properties of the seed coat, making it more prone to splitting. Further analyses uncovered differences in the physical properties of the seed coat between Yukihomare and Toiku 248. In particular, seed coat hardness decreased in Yukihomare, but not in Toiku 248, under the low-temperature treatment. Seed coat flexibility was higher in Toiku 248 than in Yukihomare under the low-temperature treatment, suggesting that the seed coat of low-temperature-treated Toiku 248 is more flexible than that of low-temperature-treated Yukihomare. These physical properties of the Toiku 248 seed coat observed under low-temperature conditions may contribute to its seed-cracking tolerance.


Assuntos
Lignina/metabolismo , Proantocianidinas/metabolismo , Sementes/fisiologia , Soja/fisiologia , Parede Celular/metabolismo , Temperatura Baixa , Pigmentação , Sementes/citologia , Soja/citologia
7.
Cryo Letters ; 39(1): 60-66, 2018 Jan/Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29734416

RESUMO

  BACKGROUND: A cryopreservation protocol has been established for oil palm somatic embryos (SEs), the efficiency of which must be evaluated, both in terms of regeneration and of long-term storage capacity, before its large-scale routine use. OBJECTIVE: To test the survival and recovery of 29 clones of oil palm somatic embryos cryostored for 20 years. MATERIALS AND METHODS: Clumps of SEs were pregrown for 7 days on medium containing 0.75 M sucrose, dehydrated in air-tight containers containing silica gel to moisture contents between 19-35% fresh weight, and then immersed directly in liquid nitrogen and stored in cryotanks for 20 years. RESULTS: Survival of SEs cryopreserved and rewarmed immediately displayed an average value of 19.1% for the 29 clones tested while survival of SEs rewarmed after 20 years of cryostorage was significantly higher, with an average of 33.2% for the 28 surviving clones. Out of these 28 surviving clones, three were lost due to contamination or regrowth decline, six produced only shoots and the rest proliferated. CONCLUSION: It is possible to cryostore oil palm SEs for extended periods and to regenerate proliferating cultures and plantlets from the cryopreserved material. The cryopreservation protocol established can thus be efficiently used to store oil palm germplasm and to manage large-scale production in industrial laboratories.


Assuntos
Arecaceae/embriologia , Criopreservação/métodos , Óleo de Palmeira/química , Arecaceae/citologia , Arecaceae/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Regeneração/efeitos dos fármacos , Sementes/citologia , Sementes/efeitos dos fármacos , Sementes/embriologia , Sacarose/farmacologia
8.
PLoS One ; 13(3): e0192945, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29499063

RESUMO

The terminal differentiation and elimination of the embryo-suspensor is the earliest manifestation of programmed cell death (PCD) during plant ontogenesis. Molecular regulation of suspensor PCD remains poorly understood. Norway spruce (Picea abies) embryos provide a powerful model for studying embryo development because of their large size, sequenced genome, and the possibility to obtain a large number of embryos at a specific developmental stage through somatic embryogenesis. Here, we have carried out global gene expression analysis of the Norway spruce embryo-suspensor versus embryonal mass (a gymnosperm analogue of embryo proper) using RNA sequencing. We have identified that suspensors have enhanced expression of the NAC domain-containing transcription factors, XND1 and ANAC075, previously shown to be involved in the initiation of developmental PCD in Arabidiopsis. The analysis has also revealed enhanced expression of Norway spruce homologues of the known executioners of both developmental and stress-induced cell deaths, such as metacaspase 9 (MC9), cysteine endopeptidase-1 (CEP1) and ribonuclease 3 (RNS3). Interestingly, a spruce homologue of bax inhibitor-1 (PaBI-1, for Picea abies BI-1), an evolutionarily conserved cell death suppressor, was likewise up-regulated in the embryo-suspensor. Since Arabidopsis BI-1 so far has been implicated only in the endoplasmic reticulum (ER)-stress induced cell death, we investigated its role in embryogenesis and suspensor PCD using RNA interference (RNAi). We have found that PaBI-1-deficient lines formed a large number of abnormal embryos with suppressed suspensor elongation and disturbed polarity. Cytochemical staining of suspensor cells has revealed that PaBI-1 deficiency suppresses vacuolar cell death and induces necrotic type of cell death previously shown to compromise embryo development. This study demonstrates that a large number of cell-death components are conserved between angiosperms and gymnosperms and establishes a new role for BI-1 in the progression of vacuolar cell death.


Assuntos
Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Modelos Biológicos , Picea , Proteínas de Plantas , Sementes , Fatores de Transcrição , Morte Celular/fisiologia , Estresse do Retículo Endoplasmático/fisiologia , Picea/citologia , Picea/genética , Picea/metabolismo , Proteínas de Plantas/biossíntese , Proteínas de Plantas/genética , Sementes/citologia , Sementes/genética , Sementes/metabolismo , Fatores de Transcrição/biossíntese , Fatores de Transcrição/genética
9.
Plant Mol Biol ; 96(6): 627-640, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29574557

RESUMO

KEY MESSAGE: miR171a controls HAM1 functions within the protodermal cells of the embryo, and these controls are essential for normal embryogenesis in Arabidopsis. Arabidopsis thaliana miR171a is known to bind to and cleave mRNAs of three HAIRY MERISTEM (HAM) genes that encode members of the GRAS family transcriptional regulators. The molecular functions of the HAM genes are still being elucidated in Arabidopsis. However, detailed expression patterns of miR171a and the effects of the failure of miR171a to suppress HAM genes were unknown till now. Here, we show the detailed expression patterns of miR171a and HAM1 using green fluorescent protein and confocal scanning microscopy. Our observations revealed that miR171a was expressed in the surface cell layer of the embryo and shoot apical meristem, and it controlled HAM1 functions. To determine the impact of the failure of miR171a to suppress of HAM1, we introduced seven synonymous mutations into the miR171a target site of the HAM1 gene (modified HAM1, mHAM1) and generated transgenic plants that had mHAM1 driven by HAM1 native promoter. The mHAM1 transgenic plants showed organogenic defects. These results indicate that the control of HAM1 functions at the single-cell-layer level by miR171a is essential for proper organ formation in Arabidopsis.


Assuntos
Proteínas de Arabidopsis/genética , Arabidopsis/genética , Regulação da Expressão Gênica no Desenvolvimento , Regulação da Expressão Gênica de Plantas , MicroRNAs/genética , Sementes/genética , Arabidopsis/citologia , Arabidopsis/embriologia , Sequência de Bases , Sítios de Ligação/genética , Meristema/genética , Mutação , Brotos de Planta/genética , Brotos de Planta/crescimento & desenvolvimento , Plantas Geneticamente Modificadas , Sementes/citologia , Sementes/embriologia , Homologia de Sequência do Ácido Nucleico
10.
Sci China Life Sci ; 61(2): 214-224, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-29372509

RESUMO

Post-transcriptional modifications, including histone modifications and DNA methylation, alter the chromatin landscape to regulate gene expression, thus control various cellular processes in plants. EARLY FLOWERING IN SHORT DAYS (EFS) is the major contributor for H3K36 methylation in Arabidopsis and is important for plant development. Here, we find that EFS is expressed in different stages of embryo morphogenesis, and the efs mutant produces larger embryo that results in enlarged seeds. Further analysis reveals that an imprinted gene MOP9.5 is hypomethylated at the promoter region and its expression is derepressed in efs mutant. MOP9.5 promoter is marked by various epigenetic modifications, and we find that following the increase of H3K36me3, H3K27me3 and H3K9me2 levels are reduced in efs mutant. This data indicates an antagonistic regulation between H3K36me3 and DNA methylation, and/or H3K27me3 at MOP9.5. Our results further show that both maternal and paternal EFS alleles are responsible for the seed size regulation, which unraveled a novel function of EFS in plant development.


Assuntos
Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Arabidopsis/genética , Regulação da Expressão Gênica de Plantas , Histona-Lisina N-Metiltransferase/genética , Histona-Lisina N-Metiltransferase/metabolismo , Desenvolvimento Vegetal/genética , Sementes/genética , Arabidopsis/crescimento & desenvolvimento , Metilação de DNA , Epigênese Genética , Genes de Plantas/genética , Histonas/metabolismo , Plantas Geneticamente Modificadas , Regiões Promotoras Genéticas , Sementes/citologia , Sementes/embriologia
11.
Nat Prod Res ; 32(15): 1809-1816, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29172707

RESUMO

The present investigation reports the growth kinetics and diosgenin accumulation in callus cultures of Costus speciosus. Effect of explants, media and plant growth regulators was evaluated with respect to callus induction and growth. Out of the two explants viz pseudostem and seed, pseudostem showed maximum callus induction frequency of 90% on MS medium. The fresh weight of callus was maximum (9-folds) on 28th day on 1.0 mg/L picloram containing medium. The callus obtained was white compact hard (WCH). For growth kinetics study pseudostem derived callus was transferred on different media supplemented with 1.0 mg/L picloram. All phases of growth were seen in callus inoculated on all the three media except the absence of stationary phase on MS and SH media. MS medium proved to be the best for maximum biomass accumulation (9-fold) on 28th day of culture and callus in post-exponential phase showed maximum diosgenin accumulation (33 ppm).


Assuntos
Costus/citologia , Costus/crescimento & desenvolvimento , Diosgenina/metabolismo , Técnicas de Cultura de Células , Costus/metabolismo , Meios de Cultura , Cinética , Reguladores de Crescimento de Planta/farmacologia , Sementes/citologia
12.
J Inorg Biochem ; 181: 177-182, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-28867596

RESUMO

Toxicity by aluminum is a growth-limiting factor in plants cultivated in acidic soils. This metal also promotes signal transduction pathways leading to the biosynthesis of defense compounds, including secondary metabolites. In this study, we observed that Coffea arabica L. cells that were kept in the dark did not produce detectable levels of caffeine. However, irradiation with light and supplementation of the culture medium with theobromine were the best conditions for cell maintenance to investigate the role of aluminum in caffeine biosynthesis. The addition of theobromine to the cells did not cause any changes to cell growth and was useful for the bioconversion of theobromine to caffeine. During a short-term AlCl3-treatment (500µM) of C. arabica cells kept under light irradiation, increases in the caffeine levels in samples that were recovered from both the cells and culture media were evident. This augmentation coincided with increases in the enzyme activity of caffeine synthase (CS) and the transcript level of the gene encoding this enzyme (CS). Together, these results suggest that actions by Al and theobromine on the same pathway lead to the induction of caffeine biosynthesis.


Assuntos
Alumínio/toxicidade , Cafeína/metabolismo , Coffea/efeitos dos fármacos , Células do Mesofilo/efeitos dos fármacos , Raízes de Plantas/efeitos dos fármacos , Sementes/efeitos dos fármacos , Poluentes do Solo/toxicidade , Processos de Crescimento Celular/efeitos dos fármacos , Processos de Crescimento Celular/efeitos da radiação , Linhagem Celular , Células Cultivadas , Coffea/citologia , Coffea/metabolismo , Coffea/efeitos da radiação , Meios de Cultivo Condicionados/química , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Regulação da Expressão Gênica de Plantas/efeitos da radiação , Luz , Células do Mesofilo/citologia , Células do Mesofilo/metabolismo , Células do Mesofilo/efeitos da radiação , Metiltransferases/química , Metiltransferases/genética , Metiltransferases/metabolismo , Proteínas de Plantas/agonistas , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Raízes de Plantas/citologia , Raízes de Plantas/metabolismo , Raízes de Plantas/efeitos da radiação , RNA Mensageiro/metabolismo , RNA de Plantas/metabolismo , Sementes/citologia , Sementes/metabolismo , Sementes/efeitos da radiação , Teobromina/metabolismo , Regulação para Cima/efeitos dos fármacos , Regulação para Cima/efeitos da radiação
13.
PLoS One ; 12(11): e0188148, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29141031

RESUMO

The seed, the reproductive unit of angiosperms, is generally protected by the seed coat. The seed coat is made of one or two integuments, each comprising two epidermal cells layers and, in some cases, extra sub-epidermal cell layers. The thickness of the seed-coat affects several aspects of seed biology such as dormancy, germination and mortality. In Arabidopsis, the inner integument displays one or two sub-epidermal cell layers that originate from periclinal cell divisions of the innermost epidermal cell layer. By contrast, the outer integument was considered to be two-cell layered. Here, we show that sub-epidermal chalazal cells grow in between the epidermal outer integument cell layers to create an incomplete three-cell layered outer integument. We found that the MADS box transcription factor TRANSPARENT TESTA 16 represses growth of the chalaza and formation of sub-epidermal outer integument cells. Finally, we demonstrate that sub-epidermal cells of the outer and inner integument respond differently to the repressive mechanism mediated by FERTILIZATION INDEPENDENT SEED Polycomb group proteins and to fertilization signals. Our data suggest that integument cell origin rather than sub-epidermal cell position underlies different responses to fertilization.


Assuntos
Arabidopsis/embriologia , Sementes/citologia , Arabidopsis/metabolismo , Proteínas de Arabidopsis/metabolismo , Plantas Geneticamente Modificadas , Sementes/crescimento & desenvolvimento
14.
Cell Mol Biol (Noisy-le-grand) ; 63(10): 11-19, 2017 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-29096740

RESUMO

This study was carried out to investigate the response of 42 Iranian and European barley (Hordeum vulgare L.) cultivars to induced dedifferentiation of embryonic cells via immature embryo culture and understand the relationship between embryo culture characters and agronomic traits. The cultivars were evaluated for dedifferentiation of embryonic cells or callus induction from immature embryo culture based on a completely randomized design with unequal replication. Immature embryos were placed scutellum down on cell dedifferentiation medium based on MS and supplemented with 2.5 mg/l 2,4-D. The developed calli were transferred to MS regeneration medium with different concentrations and combinations of plant growth regulators. The results of group comparisons showed that Iranian cultivars were greater than European cultivars regarding callus growth rate, callus primary diameter and total regenerated plantlets. The path correlation analysis revealed that grain width and kernel filling period had the highest positive and negative direct effects on embryo culture traits, respectively. Clustering cultivars based on the embryo culture characters and agronomic traits divided the cultivars into three groups. The third group consisted of the cultivars which all of them were with the highest mean for flag leaf length, days to anthesis, grain yield, callus growth rate and callus primary diameter. Mantel test revealed a negative (-0.101) and significant correlation (P<0.01) between embryo culture characters and agronomic traits. The significant relationships between few numbers of embryo culture characters and agronomic traits confirm that these characteristics could be genetically dependent and also tissue culture characters can be estimated from agronomic data.


Assuntos
Desdiferenciação Celular/fisiologia , Células Germinativas Vegetais/fisiologia , Hordeum/embriologia , Sementes/crescimento & desenvolvimento , Meios de Cultura , Hordeum/efeitos dos fármacos , Reguladores de Crescimento de Planta/farmacologia , Distribuição Aleatória , Regeneração/fisiologia , Sementes/citologia , Estatística como Assunto , Técnicas de Cultura de Tecidos
15.
Proc Natl Acad Sci U S A ; 114(45): E9730-E9739, 2017 11 07.
Artigo em Inglês | MEDLINE | ID: mdl-29078418

RESUMO

We profiled soybean and Arabidopsis methylomes from the globular stage through dormancy and germination to understand the role of methylation in seed formation. CHH methylation increases significantly during development throughout the entire seed, targets primarily transposable elements (TEs), is maintained during endoreduplication, and drops precipitously within the germinating seedling. By contrast, no significant global changes in CG- and CHG-context methylation occur during the same developmental period. An Arabidopsis ddcc mutant lacking CHH and CHG methylation does not affect seed development, germination, or major patterns of gene expression, implying that CHH and CHG methylation does not play a significant role in seed development or in regulating seed gene activity. By contrast, over 100 TEs are transcriptionally de-repressed in ddcc seeds, suggesting that the increase in CHH-context methylation may be a failsafe mechanism to reinforce transposon silencing. Many genes encoding important classes of seed proteins, such as storage proteins, oil biosynthesis enzymes, and transcription factors, reside in genomic regions devoid of methylation at any stage of seed development. Many other genes in these classes have similar methylation patterns, whether the genes are active or repressed. Our results suggest that methylation does not play a significant role in regulating large numbers of genes important for programming seed development in both soybean and Arabidopsis. We conclude that understanding the mechanisms controlling seed development will require determining how cis-regulatory elements and their cognate transcription factors are organized in genetic regulatory networks.


Assuntos
Arabidopsis/genética , Metilação de DNA/fisiologia , DNA de Plantas/metabolismo , Sementes/crescimento & desenvolvimento , Sementes/genética , Soja/genética , Sequência de Bases , Metilação de DNA/genética , Elementos de DNA Transponíveis/genética , Elementos de DNA Transponíveis/fisiologia , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas/genética , Redes Reguladoras de Genes , Inativação Gênica , Genes de Plantas/genética , Genoma de Planta/genética , Germinação/genética , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , RNA de Plantas/genética , RNA de Plantas/metabolismo , Plântula/genética , Plântula/metabolismo , Sementes/citologia
16.
Plant Physiol ; 175(3): 1484-1496, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28972079

RESUMO

Recent discoveries have shown that epigenetic regulation is an integral part of phytohormone-mediated processes. The phytohormone gibberellin (GA) triggers a series of events in cereal aleurone cells that lead to programmed cell death (PCD), but the signaling cascade mediating GA-induced PCD in cereal aleurone layers remains largely unknown. Here, we showed that histone deacetylase (HDAC) activity gradually increased relative to histone acetyltransferase (HAT) activity, leading to a global decrease in histone H3 and H4 acetylation levels during PCD of maize (Zea mays) embryoless aleurone layers after 3 d of treatment with GA. HDAC inhibition prevented GA-induced PCD in embryoless aleurone cells, whereas HAT inhibition resulted in PCD even in the absence of GA. Hydrogen peroxide concentrations increased in GA- or HAT inhibitor-treated aleurone cells due to reduced levels of reactive oxygen species scavengers. Hydrogen peroxide-treated aleurone cells showed no changes in the activity or expression of HATs and HDACs. We show that it is possible to predict whether epigenetic modification enzymes serve as a regulator of the GA-triggered PCD signaling pathway in maize aleurone layers. Taken together, these findings reveal that HDAC activity is required for GA-induced PCD in maize aleurone layers and regulates PCD via the reactive oxygen species-mediated signal transduction pathway.


Assuntos
Apoptose/efeitos dos fármacos , Giberelinas/farmacologia , Histona Desacetilases/metabolismo , Sementes/citologia , Sementes/enzimologia , Zea mays/citologia , Zea mays/enzimologia , Acetilação , Regulação da Expressão Gênica de Plantas , Histonas/metabolismo , Modelos Biológicos , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Sementes/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , Fatores de Tempo
17.
Toxicol Ind Health ; 33(11): 843-854, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28950791

RESUMO

The increasing use of pesticides such as malathion and dithane in agriculture causes environmental mutagenicity. However, their genotoxicity in edible crops is seldom assessed. In this study, the genotoxic potential of malathion and dithane was evaluated in the roots of Vicia faba L. All three concentrations (0.05, 0.1, and 0.2%) of malathion and dithane tested resulted in a significant decrease in root length and inhibited seed germination. Cytological observations showed that the mitotic frequency in the root meristematic cells decreased parallel to the increase in concentrations, and the increase in chromosome aberrations and micronuclei frequency was concentration dependent. Alkaline comet assay revealed significant onset of DNA damage at all tested concentrations. For the randomly amplified polymorphic (RAPD)-polymerase chain reaction (PCR) analyses, 10 random RAPD primers were found to produce 116 unique polymorphic RAPD band fragments of 223-3139 bp. Each primer generated 3-15 RAPD bands on an average. The percentage of polymorphic DNA fragments was higher in malathion-exposed plants than dithane ones. The changes in RAPD profiles included disappearance and/or appearance of DNA bands in malathion and dithane treatment. Hence, DNA damage observed by the cytogenetic endpoints and comet assay corroborated with RAPD-PCR analysis. A total of 15 new protein bands of molecular weight ranging 11.894-226.669 kDa were observed in roots of Vicia plants that were exposed to the pesticides. The number of new protein bands was higher in malathion-treated DNA samples than in dithane-treated ones. Based on the results, we conclude that the pesticides can alter genomic template stability and change protein profiles. Malathion was more genotoxic than dithane. Therefore, RAPD assays can be useful in determining genotoxicity of pesticides in V. faba and other crops along with other quantitative parameters.


Assuntos
Fungicidas Industriais/toxicidade , Inseticidas/toxicidade , Malation/toxicidade , Maneb/toxicidade , Raízes de Plantas/efeitos dos fármacos , Sementes/efeitos dos fármacos , Vicia faba/efeitos dos fármacos , Zineb/toxicidade , Aberrações Cromossômicas/induzido quimicamente , Ensaio Cometa , Produtos Agrícolas/efeitos dos fármacos , Produtos Agrícolas/crescimento & desenvolvimento , Dano ao DNA , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Instabilidade Genômica/efeitos dos fármacos , Germinação/efeitos dos fármacos , Micronúcleos com Defeito Cromossômico/induzido quimicamente , Testes para Micronúcleos , Testes de Mutagenicidade , Mutagênicos/toxicidade , Concentração Osmolar , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Raízes de Plantas/citologia , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/metabolismo , Técnica de Amplificação ao Acaso de DNA Polimórfico , Sementes/citologia , Sementes/crescimento & desenvolvimento , Sementes/metabolismo , Vicia faba/citologia , Vicia faba/crescimento & desenvolvimento , Vicia faba/metabolismo
18.
Cryo Letters ; 38(3): 202-209, 2017 May/Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28767743

RESUMO

BACKGROUND: Pinus radiata is an economically important conifer, and somatic embryogenesis is being currently used for its propagation. But the embryogenic competence of cultures decreases with culture age. To cope with this, cryopreservation protocols have been developed lately for different Pinus species. Although cryopreservation reduces the costs associated with embryogenic cultures maintenance, the initial investment and the maintenance of cryotanks are expensive when dealing with somatic embryogenesis basic research issues. OBJECTIVE: To study the feasibility of storing embryogenic cell lines at -80 degree C for over a year. MATERIALS AND METHODS: The feasibility of the conservation method was assessed in terms of recovery, maturation and germination rates. RESULTS: The recovery rates were up to 77 percnt;, and maturation and germination rates were 86 percnt; and 83 percnt;, respectively. CONCLUSION: The work described here is a simple and low-cost protocol that enables successful conservation of embryogenic cell lines for over a year.


Assuntos
Criopreservação/métodos , Pinus/embriologia , Sementes , Linhagem Celular , Germinação/fisiologia , Sementes/citologia , Sementes/embriologia , Fatores de Tempo
19.
Plant Physiol ; 175(2): 758-773, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28811333

RESUMO

In flowering plants, the female gametophyte controls pollen tube reception immediately before fertilization and regulates seed development immediately after fertilization, although the controlling mechanisms remain poorly understood. Previously, we showed that LORELEI (LRE), which encodes a putative glycosylphosphatidylinositol-anchored membrane protein, is critical for pollen tube reception by the female gametophyte before fertilization and the initiation of seed development after fertilization. Here, we show that LRE is expressed in the synergid, egg, and central cells of the female gametophyte and in the zygote and proliferating endosperm of the Arabidopsis (Arabidopsis thaliana) seed. Interestingly, LRE expression in the developing seeds was primarily from the matrigenic LRE allele, indicating that LRE expression is imprinted. However, LRE was biallelically expressed in 8-d-old seedlings, indicating that the patrigenic allele does not remain silenced throughout the sporophytic generation. Regulation of imprinted LRE expression is likely novel, as LRE was not expressed in pollen or pollen tubes of mutants defective for MET1, DDM1, RNA-dependent DNA methylation, or MSI-dependent histone methylation. Additionally, the patrigenic LRE allele inherited from these mutants was not expressed in seeds. Surprisingly, and contrary to the predictions of the parental conflict hypothesis, LRE promotes growth in seeds, as loss of the matrigenic but not the patrigenic LRE allele caused delayed initiation of seed development. Our results showed that LRE is a rare imprinted gene that functions immediately after double fertilization and supported the model that a passage through the female gametophyte establishes monoalleleic expression of LRE in seeds and controls early seed development.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/genética , Glicoproteínas de Membrana/metabolismo , Arabidopsis/citologia , Arabidopsis/crescimento & desenvolvimento , Proteínas de Arabidopsis/genética , Endosperma/citologia , Endosperma/genética , Endosperma/crescimento & desenvolvimento , Fertilização , Glicoproteínas de Membrana/genética , Mutação , Especificidade de Órgãos , Óvulo Vegetal/citologia , Óvulo Vegetal/genética , Óvulo Vegetal/crescimento & desenvolvimento , Pólen/citologia , Pólen/genética , Pólen/crescimento & desenvolvimento , Tubo Polínico/citologia , Tubo Polínico/genética , Tubo Polínico/crescimento & desenvolvimento , Polinização , Plântula/citologia , Plântula/genética , Plântula/crescimento & desenvolvimento , Sementes/citologia , Sementes/genética , Sementes/crescimento & desenvolvimento , Zigoto
20.
Plant Cell ; 29(9): 2106-2125, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28814645

RESUMO

The formation of a zygote via the fusion of an egg and sperm cell and its subsequent asymmetric division herald the start of the plant's life cycle. Zygotic genome activation (ZGA) is thought to occur gradually, with the initial steps of zygote and embryo development being primarily maternally controlled, and subsequent steps being governed by the zygotic genome. Here, using maize (Zea mays) as a model plant system, we determined the timing of zygote development and generated RNA-seq transcriptome profiles of gametes, zygotes, and apical and basal daughter cells. ZGA occurs shortly after fertilization and involves ∼10% of the genome being activated in a highly dynamic pattern. In particular, genes encoding transcriptional regulators of various families are activated shortly after fertilization. Further analyses suggested that chromatin assembly is strongly modified after fertilization, that the egg cell is primed to activate the translational machinery, and that hormones likely play a minor role in the initial steps of early embryo development in maize. Our findings provide important insights into gamete and zygote activity in plants, and our RNA-seq transcriptome profiles represent a comprehensive, unique RNA-seq data set that can be used by the research community.


Assuntos
Fertilização/genética , Regulação da Expressão Gênica de Plantas , Genoma de Planta , Zea mays/genética , Zigoto/metabolismo , Padronização Corporal/genética , Ciclo Celular/genética , Separação Celular , Cromatina/metabolismo , Genes de Plantas , Células Germinativas Vegetais/metabolismo , Histonas/metabolismo , Ácidos Indolacéticos/metabolismo , Oryza/genética , Reprodutibilidade dos Testes , Sementes/citologia , Sementes/genética , Análise de Sequência de RNA , Transdução de Sinais/genética , Fatores de Tempo , Fatores de Transcrição/metabolismo , Transcriptoma/genética
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