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1.
Nat Commun ; 12(1): 4194, 2021 07 07.
Artigo em Inglês | MEDLINE | ID: mdl-34234144

RESUMO

Photomorphogenesis, light-mediated development, is an essential feature of all terrestrial plants. While chloroplast development and brassinosteroid (BR) signaling are known players in photomorphogenesis, proteins that regulate both pathways have yet to be identified. Here we report that DE-ETIOLATION IN THE DARK AND YELLOWING IN THE LIGHT (DAY), a membrane protein containing DnaJ-like domain, plays a dual-role in photomorphogenesis by stabilizing the BR receptor, BRI1, as well as a key enzyme in chlorophyll biosynthesis, POR. DAY localizes to both the endomembrane and chloroplasts via its first transmembrane domain and chloroplast transit peptide, respectively, and interacts with BRI1 and POR in their respective subcellular compartments. Using genetic analysis, we show that DAY acts independently on BR signaling and chlorophyll biogenesis. Collectively, this work uncovers DAY as a factor that simultaneously regulates BR signaling and chloroplast development, revealing a key regulator of photomorphogenesis that acts across cell compartments.


Assuntos
Proteínas de Arabidopsis/metabolismo , Proteínas de Choque Térmico HSP40/metabolismo , Proteínas de Membrana/metabolismo , Morfogênese/fisiologia , Proteínas Quinases/metabolismo , Arabidopsis/genética , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Brassinosteroides/metabolismo , Clorofila/biossíntese , Cloroplastos/metabolismo , Estiolamento/fisiologia , Regulação da Expressão Gênica de Plantas/fisiologia , Técnicas de Silenciamento de Genes , Proteínas de Choque Térmico HSP40/genética , Proteínas de Choque Térmico HSP40/isolamento & purificação , Luz , Proteínas de Membrana/genética , Proteínas de Membrana/isolamento & purificação , Proteínas Associadas aos Microtúbulos/genética , Proteínas Associadas aos Microtúbulos/metabolismo , Morfogênese/efeitos da radiação , Mutação , Plantas Geneticamente Modificadas , Proteínas Quinases/genética , RNA-Seq , Proteínas Recombinantes/genética , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo , Plântula/crescimento & desenvolvimento , Transdução de Sinais/fisiologia
2.
Int J Mol Sci ; 22(7)2021 Mar 24.
Artigo em Inglês | MEDLINE | ID: mdl-33804852

RESUMO

Light is the primary regulator of various biological processes during the plant life cycle. Although plants utilize photosynthetically active radiation to generate chemical energy, they possess several photoreceptors that perceive light of specific wavelengths and then induce wavelength-specific responses. Light is also one of the key determinants of the initiation of leaf senescence, the last stage of leaf development. As the leaf photosynthetic activity decreases during the senescence phase, chloroplasts generate a variety of light-mediated retrograde signals to alter the expression of nuclear genes. On the other hand, phytochrome B (phyB)-mediated red-light signaling inhibits the initiation of leaf senescence by repressing the phytochrome interacting factor (PIF)-mediated transcriptional regulatory network involved in leaf senescence. In recent years, significant progress has been made in the field of leaf senescence to elucidate the role of light in the regulation of nuclear gene expression at the molecular level during the senescence phase. This review presents a summary of the current knowledge of the molecular mechanisms underlying light-mediated regulation of leaf senescence.


Assuntos
Folhas de Planta/crescimento & desenvolvimento , Luz Solar , Estiolamento , Fotossíntese , Folhas de Planta/metabolismo , Folhas de Planta/efeitos da radiação , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais
3.
New Phytol ; 231(3): 1023-1039, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-33666236

RESUMO

Arabidopsis histone H3 lysine 4 (H3K4) demethylases play crucial roles in several developmental processes, but their involvement in seedling establishment remain unexplored. Here, we show that Arabidopsis JUMONJI DOMAIN-CONTAINING PROTEIN17 (JMJ17), an H3K4me3 demethylase, is involved in cotyledon greening during seedling establishment. Dark-grown seedlings of jmj17 accumulated a high concentration of protochlorophyllide, an intermediate metabolite in the tetrapyrrole biosynthesis (TPB) pathway that generates chlorophyll (Chl) during photomorphogenesis. Upon light irradiation, jmj17 mutants displayed decreased cotyledon greening and reduced Chl level compared with the wild-type; overexpression of JMJ17 completely rescued the jmj17-5 phenotype. Transcriptomics analysis uncovered that several genes encoding key enzymes involved in TPB were upregulated in etiolated jmj17 seedlings. Consistently, chromatin immunoprecipitation-quantitative PCR revealed elevated H3K4me3 level at the promoters of target genes. Chromatin association of JMJ17 was diminished upon light exposure. Furthermore, JMJ17 interacted with PHYTOCHROME INTERACTING FACTOR1 in the yeast two-hybrid assay. JMJ17 binds directly to gene promoters to demethylate H3K4me3 to suppress PROTOCHLOROPHYLLIDE OXIDOREDUCTASE C expression and TPB in the dark. Light results in de-repression of gene expression to modulate seedling greening during de-etiolation. Our study reveals a new role for histone demethylase JMJ17 in controlling cotyledon greening in etiolated seedlings during the dark-to-light transition.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Arabidopsis/genética , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Clorofila , Cotilédone/genética , Cotilédone/metabolismo , Estiolamento , Regulação da Expressão Gênica de Plantas , Luz , Plântula/genética , Plântula/metabolismo
4.
J Plant Physiol ; 260: 153409, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33774509

RESUMO

Sugar accumulation in maize (Zea mays) coleoptile and mesocotyl cells was suppressed when etiolated seedlings were subjected to white light irradiation. Regulation mechanisms of sugar accumulation by light in cells of both organs were studied. Sucrose exudation from the endosperm was suppressed in light-treated seedlings. In addition, the activities and transcript levels of sucrose-phosphate synthase (SPS) in scutella were decreased following light irradiation. These results suggest that sucrose exudation from the endosperm is decreased by the suppression of SPS activities via downregulation of its gene expression. In coleoptiles and mesocotyls, light irradiation also decreased the activities and transcript levels of cell wall-bound invertase, suggesting that phloem unloading processes were suppressed. Thus, inhibition of both sucrose loading from the endosperm and sucrose unloading in coleoptiles and mesocotyls may be involved in the suppression of sugar accumulation in coleoptiles and mesocotyls irradiated with white light.


Assuntos
Cotilédone/metabolismo , Estiolamento , Luz , Sacarose/metabolismo , Zea mays/metabolismo , Plântula/metabolismo , Plântula/efeitos da radiação , Zea mays/efeitos da radiação
5.
Methods Mol Biol ; 2297: 49-60, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33656669

RESUMO

Seedlings grown in darkness exhibit distinct morphologies comparing with light-grown seedlings. Elongated hypocotyls, closed yellow cotyledons, and the formation of apical hooks are typical characteristics for etiolated seedlings, which are collectively named skotomorphogenesis. Various plant hormones and environmental factors are essential for maintaining skotomorphogenesis. Due to the diverse morphological outcomes in etiolated seedlings grown under different treatments, studies on skotomorphogenesis are of particular importance to reveal the molecular mechanisms underlying plant response to environmental cues. Here, we detailed experimental procedures to facilitate researchers who are investigating etiolation growth-related studies.


Assuntos
Proteínas de Arabidopsis/genética , Arabidopsis/crescimento & desenvolvimento , Estiolamento/efeitos dos fármacos , Reguladores de Crescimento de Plantas/farmacologia , Arabidopsis/efeitos dos fármacos , Arabidopsis/genética , Cotilédone/efeitos dos fármacos , Cotilédone/genética , Cotilédone/crescimento & desenvolvimento , Regulação da Expressão Gênica no Desenvolvimento/efeitos dos fármacos , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Hipocótilo/efeitos dos fármacos , Hipocótilo/genética , Hipocótilo/crescimento & desenvolvimento , Temperatura
6.
Methods Mol Biol ; 2297: 95-103, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33656673

RESUMO

Seedling deetiolation is a hallmark of the photomorphogenic response, and successful conversion of protochlorophyllide (Pchlide) into chlorophyllide during initial light exposure is critical for plant survival and growth. Here we describe the seedling deetiolation process of two typical mutants pif3 and flu by analysis of the cotyledons greening, Pchlide content, and reactive oxygen species (ROS) production and summarize a set of general methods for the research of seedling greening.


Assuntos
Proteínas de Arabidopsis/genética , Arabidopsis/crescimento & desenvolvimento , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Protoclorifilida/metabolismo , Arabidopsis/química , Arabidopsis/genética , Clorofilídeos/metabolismo , Estiolamento , Regulação da Expressão Gênica de Plantas , Mutação , Espécies Reativas de Oxigênio/metabolismo , Plântula/química , Plântula/genética , Plântula/crescimento & desenvolvimento
7.
Chemosphere ; 267: 128918, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33218729

RESUMO

Antibiotic pollution has become an important global issue, and ofloxacin (OFL) is widely used worldwide. However, little is known about the potential adverse effects of OFL on plants. We assessed the toxic effects of OFL on Welsh onion and explored its toxicity mechanism. The leaf pigment content increased in 0.1 mg/L of OFL but decreased in a dose-dependent manner (0.5-2 mg/L OFL) until leaf etiolation. The ultrastructure of leaves showed that the treatment of 2 mg/L OFL produced significant toxicity. Furthermore, photosynthetic and fluorescence parameters were negatively affected by OFL treatment. The photosynthetic electron transport chain was significantly inhibited by OFL treatment, especially between QA and QB. The hydrogen peroxide and malondialdehyde content also increased with OFL concentration, indicating that antioxidant enzymes' role in antibiotic response is limited. In conclusion, OFL can damage chloroplasts by promoting ROS accumulation, which results in the etiolation of Welsh onion leaves.


Assuntos
Ofloxacino , Cebolas , Antibacterianos/toxicidade , Estiolamento , Ofloxacino/toxicidade , Fotossíntese , Folhas de Planta
8.
Plant Cell ; 32(12): 3792-3811, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33093148

RESUMO

Following germination in the dark, Arabidopsis (Arabidopsis thaliana) seedlings undergo etiolation and develop apical hooks, closed cotyledons, and rapidly elongating hypocotyls. Upon light perception, the seedlings de-etiolate, which includes the opening of apical hooks and cotyledons. Here, we identify Arabidopsis Small Auxin Up RNA17 (SAUR17) as a downstream effector of etiolation, which serves to bring about apical hook formation and closed cotyledons. SAUR17 is highly expressed in apical hooks and cotyledons and is repressed by light. The apical organs also express a group of light-inducing SAURs, as represented by SAUR50, which promote hook and cotyledon opening. The development of etiolated or de-etiolated apical structures requires asymmetric differential cell growth. We present evidence that the opposing actions of SAUR17 and SAUR50 on apical development largely result from their antagonistic regulation of Protein Phosphatase 2C D-clade 1 (PP2C-D1), a phosphatase that suppresses cell expansion and promotes apical hook development in the dark. SAUR50 inhibits PP2C-D1, whereas SAUR17 has a higher affinity for PP2C-D1 without inhibiting its activity. PP2C-D1 predominantly associates with SAUR17 in etiolated seedlings, which shields it from inhibitory SAURs such as SAUR50. Light signals turn off SAUR17 and upregulate a subgroup of SAURs including SAUR50 at the inner side of the hook and cotyledon cells, leading to cell expansion and unfolding of the hook and cotyledons.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/genética , Regulação da Expressão Gênica de Plantas , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Transdução de Sinal Luminoso , Reguladores de Crescimento de Plantas/metabolismo , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/fisiologia , Arabidopsis/efeitos da radiação , Proteínas de Arabidopsis/genética , Cotilédone/genética , Cotilédone/crescimento & desenvolvimento , Cotilédone/fisiologia , Etilenos/metabolismo , Estiolamento , Genes Reporter , Ácidos Indolacéticos/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/genética , Luz , Proteína Fosfatase 2C/genética , Proteína Fosfatase 2C/metabolismo , Plântula/genética , Plântula/crescimento & desenvolvimento , Plântula/fisiologia , Regulação para Cima
9.
Plant Physiol ; 184(2): 570-571, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-33020326

Assuntos
Estiolamento , Luz
10.
Planta ; 252(5): 74, 2020 Oct 06.
Artigo em Inglês | MEDLINE | ID: mdl-33025156

RESUMO

MAIN CONCLUSION: In general, genes promoting IAA, CTK GA and ethylene biosynthesis were upregulated, while genes participating in ABA, chlorophyll and starch biosynthesis pathways performed opposite tendency during etiolation. Etiolation as a method for rejuvenation plays an important role in the vegetative propagation of woody plants. However, the molecular mechanism of etiolated shoot development remains unclear. In this study, we investigated changes at different etiolation stages of Juglans regia. The histology and transcriptome of J. regia were analysed using etiolated stems, which were treated in darkness for 30, 60, 90 days. The results showed that the ratios of pith (Pi) diameter/stem diameter (D), cortex (Co) width/D, and phloem (Ph) width/D increased, while the ratio of xylem (Xy) width/D decreased after etiolation, and the difference in these ratios between etiolated stems and the control was more significant at 60 days than 90 days. Differentially expressed genes (DEGs) were significantly enriched in pathways such as plant hormone biosynthesis and signal transduction, chlorophyll biosynthesis and degradation, and starch and sucrose metabolism. The difference in the contents of indole-3-acetic acid (IAA), abscisic acid (ABA), sugar and chlorophyll between etiolated stems and the control increased with increasing treatment duration; in contrast, the concentrations of gibberellin (GA), zeatin (ZT), and starch, as well as the difference between the etiolated stems and control were lowest at 60 days among the three stages. On the whole, the positive effect of etiolation on the rejuvenation of walnut stems changed as the treatment period increased. The present investigation lays a foundation for future studies on the effect of etiolation on rejuvenation and for promoting the efficiency of vegetative propagation.


Assuntos
Juglans , Brotos de Planta , Transcriptoma , Estiolamento , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Juglans/genética , Juglans/crescimento & desenvolvimento , Reguladores de Crescimento de Plantas/metabolismo , Brotos de Planta/crescimento & desenvolvimento , Transcriptoma/genética
11.
Int J Mol Sci ; 21(21)2020 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-33126662

RESUMO

Vanilla orchid, which is well-known for its flavor and fragrance, is cultivated in tropical and subtropical regions. This shade-loving plant is very sensitive to high irradiance. In this study, we show that vanilla chloroplasts started to have avoidance movement when blue light (BL) was higher than 20 µmol m-2s-1 and significant avoidance movement was observed under BL irradiation at 100 µmol m-2s-1 (BL100). The light response curve indicated that when vanilla was exposed to 1000 µmol m-2s-1, the electron transport rate (ETR) and photochemical quenching of fluorescence (qP) were significantly reduced to a negligible amount. We found that if a vanilla orchid was irradiated with BL100 for 12 days, it acquired BL-acclimation. Chloroplasts moved to the side of cells in order to reduce light-harvesting antenna size, and chloroplast photodamage was eliminated. Therefore, BL-acclimation enhanced vanilla orchid growth and tolerance to moderate (500 µmol m-2s-1) and high light (1000 µmol m-2s-1) stress conditions. It was found that under high irradiation, BL-acclimatized vanilla maintained higher ETR and qP capacity than the control without BL-acclimation. BL-acclimation induced antioxidant enzyme activities, reduced ROS accumulation, and accumulated more carbohydrates. Moreover, BL-acclimatized orchids upregulated photosystem-II-associated marker genes (D1 and PetC), Rubisco and PEPC transcripts and sustained expression levels thereof, and also maximized the photosynthesis rate. Consequently, BL-acclimatized orchids had higher biomass. In short, this study found that acclimating vanilla orchid with BL before transplantation to the field might eliminate photoinhibition and enhance vanilla growth and production.


Assuntos
Clorofila/metabolismo , Cloroplastos/metabolismo , Estiolamento , Luz , Fotossíntese , Vanilla/crescimento & desenvolvimento , Cloroplastos/efeitos da radiação , Fluorescência , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/metabolismo , Folhas de Planta/efeitos da radiação , Vanilla/metabolismo , Vanilla/efeitos da radiação
12.
Planta ; 252(4): 60, 2020 Sep 22.
Artigo em Inglês | MEDLINE | ID: mdl-32964359

RESUMO

MAIN CONCLUSION: AS events affect genes encoding protein domain composition and make the single gene produce more proteins with a certain number of genes to satisfy the establishment of photosynthesis during de-etiolation. The drastic switch from skotomorphogenic to photomorphogenic development is an excellent system to elucidate rapid developmental responses to environmental stimuli in plants. To decipher the effects of different light wavelengths on de-etiolation, we illuminated etiolated maize seedlings with blue, red, blue-red mixed and white light, respectively. We found that blue light alone has the strongest effect on photomorphogenesis and that this effect can be attributed to the higher number and expression levels of photosynthesis and chlorosynthesis proteins. Deep sequencing-based transcriptome analysis revealed gene expression changes under different light treatments and a genome-wide alteration in alternative splicing (AS) profiles. We discovered 41,188 novel transcript isoforms for annotated genes, which increases the percentage of multi-exon genes with AS to 63% in maize. We provide peptide support for all defined types of AS, especially retained introns. Further in silico prediction revealed that 58.2% of retained introns have changes in domains compared with their most similar annotated protein isoform. This suggests that AS acts as a protein function switch allowing rapid light response through the addition or removal of functional domains. The richness of novel transcripts and protein isoforms also demonstrates the potential and importance of integrating proteomics into genome annotation in maize.


Assuntos
Processamento Alternativo , Plântula , Transcriptoma , Zea mays , Processamento Alternativo/genética , Estiolamento/genética , Regulação da Expressão Gênica de Plantas , Luz , Proteoma , Plântula/genética , Zea mays/genética
13.
Life Sci Space Res (Amst) ; 26: 55-61, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32718687

RESUMO

This paper introduces the use of microarray data technology with Medicago (Medicago truncatula) microarrays to characterize global changes in the transcript abundance of etiolated Alaska pea (Pisum sativum L.) seedlings grown under microgravity (µg) conditions in comparison with those under artificial 1 g conditions on the International Space Station. Of the 44,000 genes of the Medicago microarray platform, more than 25,000 transcripts of pea seedlings were hybridized, suggesting that the microarray platform for Medicago could be useful in the study of gene expression of etiolated pea seedlings grown under µg conditions in space. Gene array data were analyzed according to stringent criteria that restricted the scored genes for specific hybridization values at least twofold. Expression of 1362 and 1558 genes in proximal side (the proximal side) and distal side of the epicotyl to the cotyledons (the distal side), respectively, were highly affected by µg conditions in space. Of the genes analyzed, 407 of 1362 transcripts in the proximal side and 740 of 1558 transcripts in the distal side were expressed at ratios at least twofold. However, in the presence of the auxin transport inhibitor TIBA, 212 of 399 transcripts and 255 of 477 transcripts were expressed at ratios at least twofold as high in the proximal and the distal sides of epicotyls in the seedlings grown under µg conditions, respectively. Based on Venn diagram analysis, 31 transcripts and 24 transcripts were found to commonly increase and decrease, respectively, under µg conditions in space. Venn analysis revealed six auxin-related genes and three water channel AQUAPORIN genes that were responsive to gravity. Among 6 auxin-related genes, the accumulation of transcripts of Auxin-induced protein 5NG4 and Indole-3-acetic acid-amido synthetase GH3.3 tended to increase, and that of Auxin-induced protein, Auxin response factor, SAUR-like auxin-responsive family protein and Auxin response factor tended to decrease under µg conditions, whereas there were no statistic differences between under µg and artificial 1 g conditions. Similarly there were no statistic differences between under µg conditions and artificial 1 g, but the accumulation of NIP3-1 and Plasma membrane intrinsic protein11, and AQUAPORIN1/Tonoplast intrinsic protein tended to increase and decrease, respectively. A possible role of auxin-related genes and AQUAPORIN genes in regulating growth of etiolated pea seedlings grown under µg conditions in space is discussed.


Assuntos
Expressão Gênica , Ervilhas/genética , Proteínas de Plantas/genética , Voo Espacial , Ausência de Peso , Estiolamento , Ervilhas/crescimento & desenvolvimento , Ervilhas/metabolismo , Proteínas de Plantas/metabolismo , Análise Serial de Proteínas , Plântula/genética , Plântula/crescimento & desenvolvimento , Plântula/metabolismo
14.
Dokl Biochem Biophys ; 492(1): 124-129, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32632588

RESUMO

HY5 (ELONGATED HYPOCOTYL5), a bZIP transcription factor, is one of the main regulators of light and hormonal signaling. Among the targets of this gene, the genes for the transcriptional complex of chloroplasts whose coordinated expression ensures the initial stages of photomorphogenesis are particularly significant. In this study, we showed that, during de-etiolation, HY5 functions as a positive CK-dependent regulator of the expression of genes encoding proteins associated with plastid RNA polymerase (PAP), which functions below the primary chain of sensing the cytokinin signal. The absence of blocking effect of mutations of the CRY1, CRY2, PHYA, and PHYB photoreceptor genes on the CK-dependent content of PAP gene transcripts indicates the parallel action of the hormone and light in their regulation.


Assuntos
Proteínas de Arabidopsis/genética , Arabidopsis/metabolismo , Bactérias/enzimologia , Fatores de Transcrição de Zíper de Leucina Básica/genética , Citocininas/metabolismo , RNA Polimerases Dirigidas por DNA/genética , Estiolamento , Plastídeos/enzimologia , Arabidopsis/genética , Arabidopsis/crescimento & desenvolvimento , Proteínas de Arabidopsis/metabolismo , Fatores de Transcrição de Zíper de Leucina Básica/metabolismo , Cloroplastos/metabolismo , Citocininas/genética , Regulação da Expressão Gênica de Plantas , Transdução de Sinais
15.
Plant Cell ; 32(8): 2525-2542, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32487564

RESUMO

The switch from dark- to light-mediated development is critical for the survival and growth of seedlings, but the underlying regulatory mechanisms are incomplete. Here, we show that the steroids phytohormone brassinosteroids play crucial roles during this developmental transition by regulating chlorophyll biosynthesis to promote greening of etiolated seedlings upon light exposure. Etiolated seedlings of the brassinosteroids-deficient det2-1 (de-etiolated2) mutant accumulated excess protochlorophyllide, resulting in photo-oxidative damage upon exposure to light. Conversely, the gain-of-function mutant bzr1-1D (brassinazole-resistant 1-1D) suppressed the protochlorophyllide accumulation of det2-1, thereby promoting greening of etiolated seedlings. Genetic analysis indicated that phytochrome-interacting factors (PIFs) were required for BZR1-mediated seedling greening. Furthermore, we reveal that GROWTH REGULATING FACTOR 7 (GRF7) and GRF8 are induced by BZR1 and PIF4 to repress chlorophyll biosynthesis and promote seedling greening. Suppression of GRFs function by overexpressing microRNA396a caused an accumulation of protochlorophyllide in the dark and severe photobleaching upon light exposure. Additionally, BZR1, PIF4, and GRF7 interact with each other and precisely regulate the expression of chlorophyll biosynthetic genes. Our findings reveal an essential role for BRs in promoting seedling development and survival during the initial emergence of seedlings from subterranean darkness into sunlight.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/efeitos da radiação , Brassinosteroides/farmacologia , Estiolamento/genética , Luz , MicroRNAs/metabolismo , Estresse Oxidativo/efeitos da radiação , Plântula/genética , Arabidopsis/efeitos dos fármacos , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Clorofila/biossíntese , Estiolamento/efeitos dos fármacos , Estiolamento/efeitos da radiação , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Regulação da Expressão Gênica de Plantas/efeitos da radiação , MicroRNAs/genética , Estresse Oxidativo/efeitos dos fármacos , Estresse Oxidativo/genética , Ligação Proteica/efeitos dos fármacos , Ligação Proteica/efeitos da radiação , Plântula/efeitos dos fármacos , Plântula/efeitos da radiação
16.
Philos Trans R Soc Lond B Biol Sci ; 375(1801): 20190402, 2020 06 22.
Artigo em Inglês | MEDLINE | ID: mdl-32362254

RESUMO

Chloroplast-to-nucleus retrograde signalling (RS) is known to impact plant growth and development. In Arabidopsis, we and others have shown that RS affects seedling establishment by inhibiting deetiolation. In the presence of lincomycin, a chloroplast protein synthesis inhibitor that triggers RS, Arabidopsis light-grown seedlings display partial skotomorphogenesis with undeveloped plastids and closed cotyledons. By contrast, RS in monocotyledonous has been much less studied. Here, we show that emerging rice seedlings exposed to lincomycin do not accumulate chlorophyll but otherwise remain remarkably unaffected. However, by using high red (R) and blue (B) monochromatic lights in combination with lincomycin, we have uncovered a RS inhibition of length and a reduction in the B light-induced declination of the second leaf. Furthermore, we present data showing that seedlings grown in high B and R light display different non-photochemical quenching capacity. Our findings support the view that excess B and R light impact seedling photomorphogenesis differently to photoprotect and optimize the response to high-light stress. This article is part of the theme issue 'Retrograde signalling from endosymbiotic organelles'.


Assuntos
Clorofila/metabolismo , Proteínas de Cloroplastos/metabolismo , Estiolamento/efeitos da radiação , Luz , Lincomicina/farmacologia , Oryza/efeitos da radiação , Inibidores da Síntese de Proteínas/farmacologia , Transdução de Sinais/efeitos da radiação , Oryza/fisiologia , Plântula/fisiologia , Plântula/efeitos da radiação
17.
Plant Physiol ; 183(3): 1281-1294, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32414897

RESUMO

The greening of etiolated seedlings is crucial for the growth and survival of plants. After reaching the soil surface and sunlight, etiolated seedlings integrate numerous environmental signals and internal cues to control the initiation and rate of greening thus to improve their survival and adaption. However, the underlying regulatory mechanisms by which light and phytohormones, such as abscisic acid (ABA), coordinately regulate greening of the etiolated seedlings is still unknown. In this study, we showed that Arabidopsis (Arabidopsis thaliana) DE-ETIOLATED1 (DET1), a key negative regulator of photomorphogenesis, positively regulated light-induced greening by repressing ABA responses. Upon irradiating etiolated seedlings with light, DET1 physically interacts with FAR-RED ELONGATED HYPOCOTYL3 (FHY3) and subsequently associates to the promoter region of the FHY3 direct downstream target ABA INSENSITIVE5 (ABI5). Further, DET1 recruits HISTONE DEACETYLASE6 to the locus of the ABI5 promoter and reduces the enrichments of H3K27ac and H3K4me3 modification, thus subsequently repressing ABI5 expression and promoting the greening of etiolated seedlings. This study reveals the physiological and molecular function of DET1 and FHY3 in the greening of seedlings and provides insights into the regulatory mechanism by which plants integrate light and ABA signals to fine-tune early seedling establishment.


Assuntos
Ácido Abscísico/farmacologia , Arabidopsis/fisiologia , Luz , Plântula/fisiologia , Acetilação , Arabidopsis/efeitos dos fármacos , Arabidopsis/genética , Arabidopsis/efeitos da radiação , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Escuridão , Estiolamento/efeitos dos fármacos , Estiolamento/efeitos da radiação , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Regulação da Expressão Gênica de Plantas/efeitos da radiação , Histona Desacetilases/genética , Histona Desacetilases/metabolismo , Histonas/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Metilação , Fitocromo/genética , Fitocromo/metabolismo , Ligação Proteica/efeitos dos fármacos , Ligação Proteica/efeitos da radiação , Plântula/efeitos dos fármacos , Plântula/efeitos da radiação , Transcrição Genética/efeitos dos fármacos , Transcrição Genética/efeitos da radiação
18.
Plant Cell Physiol ; 61(6): 1191-1203, 2020 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-32333782

RESUMO

Growth of etiolated Arabidopsis hypocotyls is biphasic. During the first phase, cells elongate slowly and synchronously. At 48 h after imbibition, cells at the hypocotyl base accelerate their growth. Subsequently, this rapid elongation propagates through the hypocotyl from base to top. It is largely unclear what regulates the switch from slow to fast elongation. Reverse genetics-based screening for hypocotyl phenotypes identified three independent mutant lines of At1g70990, a short extensin (EXT) family protein that we named EXT33, with shorter etiolated hypocotyls during the slow elongation phase. However, at 72 h after imbibition, these dark-grown mutant hypocotyls start to elongate faster than the wild type (WT). As a result, fully mature 8-day-old dark-grown hypocotyls were significantly longer than WTs. Mutant roots showed no growth phenotype. In line with these results, analysis of native promoter-driven transcriptional fusion lines revealed that, in dark-grown hypocotyls, expression occurred in the epidermis and cortex and that it was strongest in the growing part. Confocal and spinning disk microscopy on C-terminal protein-GFP fusion lines localized the EXT33-protein to the ER and cell wall. Fourier-transform infrared microspectroscopy identified subtle changes in cell wall composition between WT and the mutant, reflecting altered cell wall biomechanics measured by constant load extensometry. Our results indicate that the EXT33 short EXT family protein is required during the first phase of dark-grown hypocotyl elongation and that it regulates the moment and extent of the growth acceleration by modulating cell wall extensibility.


Assuntos
Proteínas de Arabidopsis/fisiologia , Arabidopsis/crescimento & desenvolvimento , Hipocótilo/crescimento & desenvolvimento , Proteínas de Membrana/fisiologia , Alelos , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Parede Celular/metabolismo , Cotilédone/metabolismo , Estiolamento , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas/genética , Hipocótilo/metabolismo , Proteínas de Membrana/genética , Filogenia , Raízes de Plantas/metabolismo , Alinhamento de Sequência , Espectroscopia de Infravermelho com Transformada de Fourier
19.
J Plant Physiol ; 248: 153158, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32240968

RESUMO

Lysine acetylation is one of the most important post-translational modifications and is involved in multiple cellular processes in plants. There is evidence that acetylation may play an important role in light-induced de-etiolation, a key developmental switch from skotomorphogenesis to photomorphogenesis. During this transition, establishment of photosynthesis is of great significance. However, studies on acetylome dynamics during de-etiolation are limited. Here, we performed the first global lysine acetylome analysis for Zea mays seedlings undergoing de-etiolation, using nano liquid chromatography coupled to tandem mass spectrometry, and identified 814 lysine-acetylated sites on 462 proteins. Bioinformatics analysis of this acetylome showed that most of the lysine-acetylated proteins are predicted to be located in the cytoplasm, nucleus, chloroplast, and mitochondria. In addition, we detected ten lysine acetylation motifs and found that the accumulation of 482 lysine-acetylated peptides corresponding to 289 proteins changed significantly during de-etiolation. These proteins include transcription factors, histones, and proteins involved in chlorophyll synthesis, photosynthesis light reaction, carbon assimilation, glycolysis, the TCA cycle, amino acid metabolism, lipid metabolism, and nucleotide metabolism. Our study provides an in-depth dataset that extends our knowledge of in vivo acetylome dynamics during de-etiolation in monocots. This dataset promotes our understanding of the functional consequences of lysine acetylation in diverse cellular metabolic regulatory processes, and will be a useful toolkit for further investigations of the lysine acetylome and de-etiolation in plants.


Assuntos
Estiolamento , Lisina/metabolismo , Metaboloma , Proteínas de Plantas/metabolismo , Luz Solar , Zea mays/fisiologia , Acetilação , Zea mays/efeitos da radiação
20.
BMC Plant Biol ; 20(1): 68, 2020 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-32041529

RESUMO

BACKGROUND: Leaf color is a major agronomic trait, which has a strong influence on crop yields. Isolating leaf color mutants can represent valuable materials for research in chlorophyll (Chl) biosynthesis and metabolism regulation. RESULTS: In this study, we identified a stably inherited yellow leaf mutant derived from 'Huaguan' pakchoi variety via isolated microspore culture and designated as pylm. This mutant displayed yellow leaves after germination. Its etiolated phenotype was nonlethal and stable during the whole growth period. Its growth was weak and its hypocotyls were markedly elongated. Genetic analysis revealed that two recessive nuclear genes, named py1 and py2, are responsible for the etiolation phenotype. Bulked segregant RNA sequencing (BSR-Seq) showed that py1 and py2 were mapped on chromosomes A09 and A07, respectively. The genes were single Mendelian factors in F3:4 populations based on a 3:1 phenotypic segregation ratio. The py1 was localized to a 258.3-kb interval on a 34-gene genome. The differentially expressed gene BraA09004189 was detected in the py1 mapping region and regulated heme catabolism. One single-nucleotide polymorphism (SNP) of BraA09004189 occurred in pylm. A candidate gene-specific SNP marker in 1520 F3:4 yellow-colored individuals co-segregated with py1. For py2, 1860 recessive homozygous F3:4 individuals were investigated and localized py2 to a 4.4-kb interval. Of the five genes in this region, BraA07001774 was predicted as a candidate for py2. It encoded an embryo defective 1187 and a phosphotransferase related to chlorophyll deficiency and hypocotyl elongation. One SNP of BraA07001774 occurred in pylm. It caused a single amino acid mutation from Asp to Asn. According to quantitative real-time polymerase chain reaction (qRT-PCR), BraA07001774 was downregulated in pylm. CONCLUSIONS: Our study identified a Chl deficiency mutant pylm in pakchoi. Two recessive nuclear genes named py1 and py2 had a significant effect on etiolation. Candidate genes regulating etiolation were identified as BraA09004189 and BraA07001774, respectively. These findings will elucidate chlorophyll metabolism and the molecular mechanisms of the gene interactions controlling pakchoi etiolation.


Assuntos
Brassica rapa/genética , Estiolamento/genética , Genes de Plantas , Genes Recessivos , Proteínas de Plantas/genética , Sequência de Aminoácidos , Sequência de Bases , Brassica rapa/crescimento & desenvolvimento , Clorofila/metabolismo , Folhas de Planta , Proteínas de Plantas/química , Proteínas de Plantas/metabolismo , Alinhamento de Sequência
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