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1.
Plant J ; 2024 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-39093617

RESUMO

Being a bona fide actin bundler, Arabidopsis villin5 (VLN5) plays a crucial role in regulating actin stability and organization within pollen tubes. Despite its significance, the precise mechanism through which VLN5 bundles actin filaments has remained elusive. Through meticulous deletion analysis, we have unveiled that the link between gelsolin repeat 6 (G6) and the headpiece domain (VHP), rather than VHP itself, is indispensable for VLN5-mediated actin bundling. Further refinement of this region has pinpointed a critical sequence spanning from Val763 to Ser823, essential for VLN5's actin-bundling activity. Notably, the absence of Val763-Ser823 in VLN5 results in decreased filamentous decoration within pollen tubes and a diminished ability to rescue actin bundling defects in vln2vln5 mutant pollen tubes compared to intact VLN5. Moreover, our findings highlight that the Val763-Ser823 sequence harbors a binding site for F-actin, suggesting that this linker-based F-actin binding site, in conjunction with the F-actin binding site localized in G1-G6, enables a single VLN5 to concurrently bind to two adjacent actin filaments. Therefore, our study unveils a novel mechanism by which VLN5 bundles actin filaments.

2.
Int J Mol Sci ; 25(15)2024 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-39125592

RESUMO

The ethylene-regulated hypocotyl elongation of Arabidopsis thaliana involves many transcription factors. The specific role of MYC transcription factors in ethylene signal transduction is not completely understood. The results here revealed that two MYCs, MYC2 and MYC3, act as negative regulators in ethylene-suppressed hypocotyl elongation. Etiolated seedlings of the loss-of-function mutant of MYC2 or MYC3 were significantly longer than wild-type seedlings. Single- or double-null mutants of MYC2 and MYC3 displayed remarkably enhanced response to ACC(1-aminocyclopropane-1-carboxylate), the ethylene precursor, compared to wild-type seedlings. MYC2 and MYC3 directly bind to the promoter zone of ERF1, strongly suppressing its expression. Additionally, EIN3, a key component in ethylene signaling, interacts with MYC2 or MYC3 and significantly suppresses their binding to ERF1's promoter. MYC2 and MYC3 play crucial roles in the ethylene-regulated expression of functional genes. The results revealed the novel role and functional mechanism of these transcription factors in ethylene signal transduction. The findings provide valuable information for deepening our understanding of their role in regulating plant growth and responding to stress.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Etilenos , Regulação da Expressão Gênica de Plantas , Hipocótilo , Regiões Promotoras Genéticas , Fatores de Transcrição , Arabidopsis/genética , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Etilenos/metabolismo , Hipocótilo/crescimento & desenvolvimento , Hipocótilo/genética , Hipocótilo/metabolismo , Fatores de Transcrição/metabolismo , Fatores de Transcrição/genética , Proteínas de Ligação a DNA/metabolismo , Proteínas de Ligação a DNA/genética , Fatores de Transcrição de Zíper de Leucina e Hélice-Alça-Hélix Básicos/metabolismo , Fatores de Transcrição de Zíper de Leucina e Hélice-Alça-Hélix Básicos/genética , Plântula/crescimento & desenvolvimento , Plântula/genética , Plântula/metabolismo , Transdução de Sinais , Fatores de Transcrição de Zíper de Leucina Básica/metabolismo , Fatores de Transcrição de Zíper de Leucina Básica/genética , Fatores de Terminação de Peptídeos , Transativadores
3.
Int J Mol Sci ; 23(9)2022 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-35563188

RESUMO

Red-skinned pears are favored by people for their attractive appearance and abundance of anthocyanins. However, the molecular basis of anthocyanin biosynthesis in red pears remains elusive. Here, a comprehensive transcriptome analysis was conducted to explore the potential regulatory mechanism of anthocyanin biosynthesis in 'Red Zaosu' pear (Pyrus pyrifolia × Pyrus communis). Gene co-expression analysis and transcription factor mining identified 263 transcription factors, which accounted for 6.59% of the total number of transcription factors in the pear genome in two gene modules that are highly correlated with anthocyanin biosynthesis. Clustering, gene network modeling with STRING-DB, and local motif enrichment analysis (CentriMo) analysis suggested that PpPIF8 may play a role in anthocyanin biosynthesis. Furthermore, eight PIFs were identified in the pear genome, of which only PpPIF8 was rapidly induced by light. Functional studies showed that PpPIF8 localizes in the nucleus and is preferentially expressed in the tissue of higher levels of anthocyanin. The overexpression of PpPIF8 in pear peel and pear calli promotes anthocyanin biosynthesis and upregulates the expression of anthocyanin biosynthesis genes. Yeast-one hybrid and transgenic analyses indicated that PpPIF8 binds to the PpCHS promoter to induce PpCHS expression. The positive effect of PpPIF8 on anthocyanin biosynthesis is different from previously identified negative regulators of PyPIF5 and MdPIF7 in pear and apple. Taken together, our data not only provide a comprehensive view of transcription events during the coloration of pear peel, but also resolved the regulatory role of PpPIF8 in the anthocyanin biosynthesis pathway.


Assuntos
Pyrus , Antocianinas/metabolismo , Frutas/metabolismo , Regulação da Expressão Gênica de Plantas , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Pyrus/metabolismo , RNA-Seq , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
4.
Plant Cell Physiol ; 61(4): 685-698, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-32049334

RESUMO

Extracellular adenosine triphosphate (eATP) is an apoplastic signaling molecule that plays an essential role in the growth and development of plants. Arabidopsis seedlings have been reported to respond to eATP; however, the downstream signaling components are still not well understood. In this study, we report that an ethylene-responsive factor, Redox-Responsive Transcription Factor 1 (RRTF1), is involved in eATP-regulated Arabidopsis thaliana seedling growth. Exogenous adenosine triphosphate inhibited green seedling root growth and induced hypocotyl bending of etiolated seedlings. RRTF1 loss-of-function mutant (rrtf1) seedlings showed decreased responses to eATP, while its complementation or overexpression led to recovered or increased eATP responsiveness. RRTF1 was expressed rapidly after eATP stimulation and then migrated into the nuclei of root tip cells. eATP-induced auxin accumulation in root tip or hypocotyl cells was impaired in rrtf1. Chromatin immunoprecipitation and high-throughput sequencing results indicated that eATP induced some genes related to cell growth and development in wild type but not in rrtf1 cells. These results suggest that RRTF1 may be involved in eATP signaling by regulating functional gene expression and cell metabolism in Arabidopsis seedlings.


Assuntos
Trifosfato de Adenosina/metabolismo , Proteínas de Arabidopsis/metabolismo , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/metabolismo , Fatores de Transcrição/metabolismo , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Etilenos/metabolismo , Regulação da Expressão Gênica de Plantas , Hipocótilo/metabolismo , Ácidos Indolacéticos/metabolismo , Raízes de Plantas/metabolismo , Plântula/crescimento & desenvolvimento , Transdução de Sinais , Fatores de Transcrição/genética
5.
J Exp Bot ; 71(1): 90-104, 2020 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-31587070

RESUMO

An increased concentration of cytosolic Ca2+ is an early response of plant cells to heat shock. Arabidopsis cyclic nucleotide-gated ion channel 6 (CNGC6) mediates heat-induced Ca2+ influx and is activated by cAMP. However, it remains unclear how the Ca2+ conductivity of CNGC6 is negatively regulated under the elevated cytosolic Ca2+ concentration. In this study, Arabidopsis calmodulin isoforms CaM1/4, CaM2/3/5, CaM6, and CaM7 were found to bind to CNGC6 to varying degrees, and this binding was dependent on the presence of Ca2+ and IQ6, an atypical isoleucine-glutamine motif in CNGC6. Knockout of CaM2, CaM3, CaM5, and CaM7 genes led to a marked increase in plasma membrane inward Ca2+ current under heat shock conditions; however, knockout of CaM1, CaM4, and CaM6 genes had no significant effect on plasma membrane Ca2+ current. Moreover, the deletion of IQ6 from CNGC6 led to a marked increase in plasma membrane Ca2+ current under heat shock conditions. Taken together, the data suggest that CNGC6-mediated Ca2+ influx is likely to be negatively regulated by CaM2/3/5 and CaM7 isoforms under heat shock conditions, and that IQ6 plays an important role in CaM binding and the feedback regulation of the channel.


Assuntos
Proteínas de Arabidopsis/genética , Arabidopsis/fisiologia , Calmodulina/metabolismo , Canais de Cátion Regulados por Nucleotídeos Cíclicos/genética , Regulação da Expressão Gênica de Plantas/genética , Resposta ao Choque Térmico/genética , Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Canais de Cátion Regulados por Nucleotídeos Cíclicos/metabolismo , Isoformas de Proteínas/metabolismo
6.
PLoS Genet ; 11(9): e1005471, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26393916

RESUMO

Cell water permeability and cell wall properties are critical to survival of plant cells during freezing, however the underlying molecular mechanisms remain elusive. Here, we report that a specifically cold-induced nuclear protein, Tolerant to Chilling and Freezing 1 (TCF1), interacts with histones H3 and H4 and associates with chromatin containing a target gene, blue-copper-binding protein (BCB), encoding a glycosylphosphatidylinositol-anchored protein that regulates lignin biosynthesis. Loss of TCF1 function leads to reduced BCB transcription through affecting H3K4me2 and H3K27me3 levels within the BCB gene, resulting in reduced lignin content and enhanced freezing tolerance. Furthermore, plants with knocked-down BCB expression (amiRNA-BCB) under cold acclimation had reduced lignin accumulation and increased freezing tolerance. The pal1pal2 double mutant (lignin content reduced by 30% compared with WT) also showed the freezing tolerant phenotype, and TCF1 and BCB act upstream of PALs to regulate lignin content. In addition, TCF1 acts independently of the CBF (C-repeat binding factor) pathway. Our findings delineate a novel molecular pathway linking the TCF1-mediated cold-specific transcriptional program to lignin biosynthesis, thus achieving cell wall remodeling with increased freezing tolerance.


Assuntos
Aclimatação/genética , Proteínas de Arabidopsis/genética , Arabidopsis/genética , Proteínas de Transporte/genética , Lignina/genética , Proteínas Nucleares/genética , Arabidopsis/fisiologia , Proteínas de Arabidopsis/biossíntese , Proteínas de Transporte/biossíntese , Temperatura Baixa , Regulação da Expressão Gênica de Plantas , Técnicas de Silenciamento de Genes , Histonas/genética , Lignina/biossíntese
7.
J Exp Bot ; 66(19): 5853-66, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26085678

RESUMO

OsANN1 is a member of the annexin protein family in rice. The function of this protein and the mechanisms of its involvement in stress responses and stress tolerance are largely unknown. Here it is reported that OsANN1 confers abiotic stress tolerance by modulating antioxidant accumulation under abiotic stress. OsANN1-knockdown [RNA interference (RNAi)] plants were more sensitive to heat and drought stresses, whereas OsANN1-overexpression (OE) lines showed improved growth with higher expression of OsANN1 under abiotic stress. Overexpression of OsANN1 promoted SOD (superoxide dismutase) and CAT (catalase) activities, which regulate H2O2 content and redox homeostasis, suggesting the existence of a feedback mechanism between OsANN1 and H2O2 production under abiotic stress. Higher expression of OsANN1 can provide overall cellular protection against abiotic stress-induced damage, and a significant accumulation of OsANN1-green fluorescent protein (GFP) signals was found in the cytosol after heat shock treatment. OsANN1 also has calcium-binding and ATPase activities in vitro, indicating that OsANN1 has multiple functions in rice growth. Furthermore, yeast two-hybrid and bimolecular fluorescence complementation (BiFC) assays demonstrated that OsANN1 interacts with OsCDPK24. This cross-talk may provide additional layers of regulation in the abiotic stress response.


Assuntos
Anexinas/genética , Antioxidantes/metabolismo , Regulação da Expressão Gênica de Plantas , Oryza/genética , Proteínas de Plantas/genética , Anexinas/metabolismo , Secas , Temperatura Alta , Oryza/metabolismo , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/metabolismo , Interferência de RNA , Estresse Fisiológico
8.
Plant Cell ; 24(4): 1522-33, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22523205

RESUMO

Plant cell growth and stress signaling require Ca²âº influx through plasma membrane transport proteins that are regulated by reactive oxygen species. In root cell growth, adaptation to salinity stress, and stomatal closure, such proteins operate downstream of the plasma membrane NADPH oxidases that produce extracellular superoxide anion, a reactive oxygen species that is readily converted to extracellular hydrogen peroxide and hydroxyl radicals, OH•. In root cells, extracellular OH• activates a plasma membrane Ca²âº-permeable conductance that permits Ca²âº influx. In Arabidopsis thaliana, distribution of this conductance resembles that of annexin1 (ANN1). Annexins are membrane binding proteins that can form Ca²âº-permeable conductances in vitro. Here, the Arabidopsis loss-of-function mutant for annexin1 (Atann1) was found to lack the root hair and epidermal OH•-activated Ca²âº- and K⁺-permeable conductance. This manifests in both impaired root cell growth and ability to elevate root cell cytosolic free Ca²âº in response to OH•. An OH•-activated Ca²âº conductance is reconstituted by recombinant ANN1 in planar lipid bilayers. ANN1 therefore presents as a novel Ca²âº-permeable transporter providing a molecular link between reactive oxygen species and cytosolic Ca²âº in plants.


Assuntos
Anexina A1/metabolismo , Proteínas de Arabidopsis/metabolismo , Arabidopsis/fisiologia , Permeabilidade da Membrana Celular/efeitos dos fármacos , Membrana Celular/metabolismo , Radical Hidroxila/farmacologia , Ativação do Canal Iônico/efeitos dos fármacos , Raízes de Plantas/citologia , Arabidopsis/citologia , Arabidopsis/efeitos dos fármacos , Cálcio/metabolismo , Canais de Cálcio/metabolismo , Membrana Celular/efeitos dos fármacos , Difusão/efeitos dos fármacos , Bicamadas Lipídicas/metabolismo , Células Vegetais/efeitos dos fármacos , Células Vegetais/metabolismo , Epiderme Vegetal/efeitos dos fármacos , Epiderme Vegetal/metabolismo , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/fisiologia , Potássio/metabolismo , Protoplastos/efeitos dos fármacos , Protoplastos/metabolismo , Proteínas Recombinantes/isolamento & purificação , Superfamília Shaker de Canais de Potássio/metabolismo
9.
Plant Physiol ; 163(1): 253-62, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23886625

RESUMO

Salinity (NaCl) stress impairs plant growth and inflicts severe crop losses. In roots, increasing extracellular NaCl causes Ca²âº influx to elevate cytosolic free Ca²âº ([Ca²âº](cyt)) as a second messenger for adaptive signaling. Amplification of the signal involves plasma membrane reduced nicotinamide adenine dinucleotide phosphate oxidase activation, with the resultant reactive oxygen species triggering Ca²âº influx. The genetic identities of the Ca²âº-permeable channels involved in generating the [Ca²âº](cyt) signal are unknown. Potential candidates in the model plant Arabidopsis (Arabidopsis thaliana) include annexin1 (AtANN1). Here, luminescent detection of [Ca²âº](cyt) showed that AtANN1 responds to high extracellular NaCl by mediating reactive oxygen species-activated Ca²âº influx across the plasma membrane of root epidermal protoplasts. Electrophysiological analysis revealed that root epidermal plasma membrane Ca²âº influx currents activated by NaCl are absent from the Atann1 loss-of-function mutant. Both adaptive signaling and salt-responsive production of secondary roots are impaired in the loss-of-function mutant, thus identifying AtANN1 as a key component of root cell adaptation to salinity.


Assuntos
Anexinas/fisiologia , Proteínas de Arabidopsis/fisiologia , Arabidopsis/metabolismo , Sinalização do Cálcio/genética , Adaptação Fisiológica/genética , Anexinas/genética , Anexinas/metabolismo , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Membrana Celular/metabolismo , Raízes de Plantas/genética , Raízes de Plantas/metabolismo , Raízes de Plantas/fisiologia , Tolerância ao Sal/genética , Cloreto de Sódio/metabolismo , Estresse Fisiológico
10.
Plant Cell Environ ; 37(9): 2201-10, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-24506786

RESUMO

Controversies regarding the function of guard cell chloroplasts and the contribution of mesophyll in stomatal movements have persisted for several decades. Here, by comparing the stomatal opening of guard cells with (crl-ch) or without chloroplasts (crl-no ch) in one epidermis of crl (crumpled leaf) mutant in Arabidopsis, we showed that stomatal apertures of crl-no ch were approximately 65-70% those of crl-ch and approximately 50-60% those of wild type. The weakened stomatal opening in crl-no ch could be partially restored by imposing lower extracellular pH. Correspondingly, the external pH changes and K(+) accumulations following fusicoccin (FC) treatment were greatly reduced in the guard cells of crl-no ch compared with crl-ch and wild type. Determination of the relative ATP levels in individual cells showed that crl-no ch guard cells contained considerably lower levels of ATP than did crl-ch and wild type after 2 h of white light illumination. In addition, guard cell ATP levels were lower in the epidermis than in leaves, which is consistent with the observed weaker stomatal opening response to white light in the epidermis than in leaves. These results provide evidence that both guard cell chloroplasts and mesophyll contribute to the ATP source for H(+) extrusion by guard cells.


Assuntos
Trifosfato de Adenosina/metabolismo , Proteínas de Arabidopsis/genética , Arabidopsis/fisiologia , Cloroplastos/metabolismo , Células do Mesofilo/metabolismo , Estômatos de Plantas/citologia , Estômatos de Plantas/fisiologia , Arabidopsis/efeitos dos fármacos , Arabidopsis/efeitos da radiação , Proteínas de Arabidopsis/metabolismo , Cloroplastos/efeitos dos fármacos , Cloroplastos/efeitos da radiação , Ritmo Circadiano/efeitos dos fármacos , Ritmo Circadiano/fisiologia , Espaço Extracelular/metabolismo , Glicosídeos/farmacologia , Concentração de Íons de Hidrogênio , Luz , Células do Mesofilo/efeitos dos fármacos , Células do Mesofilo/efeitos da radiação , Estômatos de Plantas/efeitos dos fármacos , Estômatos de Plantas/efeitos da radiação , Potássio/metabolismo
11.
Plants (Basel) ; 13(9)2024 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-38732492

RESUMO

Tomato yellow leaf curl virus (TYLCV) is a prominent viral pathogen that adversely affects tomato plants. Effective strategies for mitigating the impact of TYLCV include isolating tomato plants from the whitefly, which is the vector of the virus, and utilizing transgenic lines that are resistant to the virus. In our preliminary investigations, we observed that the use of growth retardants increased the rate of TYLCV infection and intensified the damage to the tomato plants, suggesting a potential involvement of gibberellic acid (GA) in the conferring of resistance to TYLCV. In this study, we employed an infectious clone of TYLCV to inoculate tomato plants, which resulted in leaf curling and growth inhibition. Remarkably, this inoculation also led to the accumulation of GA3 and several other phytohormones. Subsequent treatment with GA3 effectively alleviated the TYLCV-induced leaf curling and growth inhibition, reduced TYLCV abundance in the leaves, enhanced the activity of antioxidant enzymes, and lowered the reactive oxygen species (ROS) levels in the leaves. Conversely, the treatment with PP333 exacerbated TYLCV-induced leaf curling and growth suppression, increased TYLCV abundance, decreased antioxidant enzyme activity, and elevated ROS levels in the leaves. The analysis of the gene expression profiles revealed that GA3 up-regulated the genes associated with disease resistance, such as WRKYs, NACs, MYBs, Cyt P450s, and ERFs, while it down-regulated the DELLA protein, a key agent in GA signaling. In contrast, PP333 induced gene expression changes that were the opposite of those caused by the GA3 treatment. These findings suggest that GA plays an essential role in the tomato's defense response against TYLCV and acts as a positive regulator of ROS scavenging and the expression of resistance-related genes.

12.
Plant J ; 70(6): 1056-69, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22372427

RESUMO

An increased concentration of cytosolic calcium ions (Ca²âº) is an early response by plant cells to heat shock. However, the molecular mechanism underlying the heat-induced initial Ca²âº response in plants is unclear. In this study, we identified and characterized a heat-activated Ca²âº-permeable channel in the plasma membrane of Arabidopsis thaliana root protoplasts using reverse genetic analysis and the whole-cell patch-clamp technique. The results indicated that A. thaliana cyclic nucleotide-gated ion channel 6 (CNGC6) mediates heat-induced Ca²âº influx and facilitates expression of heat shock protein (HSP) genes and the acquisition of thermotolerance. GUS and GFP reporter assays showed that CNGC6 expression is ubiquitous in A. thaliana, and the protein is localized to the plasma membrane of cells. Furthermore, it was found that the level of cytosolic cAMP was increased by a mild heat shock, that CNGC6 was activated by cytosolic cAMP, and that exogenous cAMP promoted the expression of HSP genes. The results reveal the role of cAMP in transduction of heat shock signals in plants. The correlation of an increased level of cytosolic cAMP in a heat-shocked plant with activation of the Ca²âº channels and downstream expression of HSP genes sheds some light on how plants transduce a heat stimulus into a signal cascade that leads to a heat shock response.


Assuntos
Proteínas de Arabidopsis/fisiologia , Arabidopsis/genética , AMP Cíclico/metabolismo , Canais de Cátion Regulados por Nucleotídeos Cíclicos/fisiologia , Resposta ao Choque Térmico , Arabidopsis/fisiologia , Proteínas de Arabidopsis/genética , Cálcio/metabolismo , Canais de Cátion Regulados por Nucleotídeos Cíclicos/genética , Citosol/metabolismo , Regulação da Expressão Gênica de Plantas , Proteínas de Choque Térmico/fisiologia , Mutagênese Insercional , Técnicas de Patch-Clamp , Transdução de Sinais
13.
Plant J ; 69(4): 689-700, 2012 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-22007900

RESUMO

Intracellular calcium (Ca(2+)) increases rapidly after heat shock (HS) in the Ca(2+)/calmodulin (Ca(2+)/CaM) HS signal transduction pathway: a hypothesis proposed based on our previous findings. However, evidence for the increase in Ca(2+) after HS was obtained only through physiological and pharmacological experiments; thus, direct molecular genetic evidence is needed. The role of phosphoinositide-specific phospholipase C (PI-PLC) is poorly understood in the plant response to HS. In this work, atplc9 mutant plants displayed a serious thermosensitive phenotype compared with wild-type (WT) plants after HS. Complementation of atplc9 with AtPLC9 rescued both the basal and acquired thermotolerance phenotype of the WT plants. In addition, thermotolerance was even improved in overexpressed lines. The GUS staining of AtPLC9 promoter:GUS transgenic seedlings showed that AtPLC9 expression was ubiquitous. The fluorescence distribution of the fusion protein AtPLC9 promoter:AtPLC9:GFP revealed that the subcellular localization of AtPLC9 was restricted to the plasma membrane. The results of a PLC activity assay showed a reduction in the accumulation of inositol-1,4,5-trisphosphate (IP(3)) in atplc9 during HS and improved IP(3) generation in the overexpressed lines. Furthermore, the heat-induced increase in intracellular Ca(2+) was decreased in atplc9. Accumulation of the small HS proteins HSP18.2 and HSP25.3 was downregulated in atplc9 and upregulated in the overexpressed lines after HS. Together, these results provide molecular genetic evidence showing that AtPLC9 plays a role in thermotolerance in Arabidopsis.


Assuntos
Aclimatação/fisiologia , Arabidopsis/enzimologia , Cálcio/metabolismo , Resposta ao Choque Térmico/fisiologia , Fosfolipases/metabolismo , Arabidopsis/genética , Arabidopsis/fisiologia , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Cálcio/análise , Membrana Celular/enzimologia , Expressão Gênica/genética , Regulação da Expressão Gênica de Plantas/genética , Proteínas de Choque Térmico/metabolismo , Temperatura Alta , Inositol 1,4,5-Trifosfato/metabolismo , Mutagênese Insercional , Fenótipo , Fosfatidilinositóis/metabolismo , Fosfolipases/genética , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/metabolismo , Regiões Promotoras Genéticas/genética , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Plântula/genética , Plântula/metabolismo , Plântula/fisiologia , Transdução de Sinais , Análise de Sobrevida
14.
Plants (Basel) ; 12(2)2023 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-36679043

RESUMO

Extracellular ATP (eATP) plays multiple roles in plant growth and development, and stress responses. It has been revealed that eATP suppresses growth and alters the growth orientation of the root and hypocotyl of Arabidopsis thaliana by affecting auxin transport and localization in these organs. However, the mechanism of the eATP-stimulated auxin distribution remains elusive. Annexins are involved in multiple aspects of plant cellular metabolism, while their role in response to apoplastic signals remains unclear. Here, by using the loss-of-function mutations, we investigated the role of AtANN3 in the eATP-regulated root and hypocotyl growth. Firstly, the inhibitory effects of eATP on root and hypocotyl elongation were weakened or impaired in the AtANN3 null mutants (atann3-1 and atann3-2). Meanwhile, the distribution of DR5-GUS and DR5-GFP indicated that the eATP-induced asymmetric distribution of auxin in the root tips or hypocotyl cells occurred in wild-type control plants, while in atann3-1 mutant seedlings, it was not observed. Further, the eATP-induced asymmetric distribution of PIN2-GFP in root-tip cells or that of PIN3-GFP in hypocotyl cells was reduced in atann3-1 seedlings. Finally, the eATP-induced asymmetric distribution of cytoplasmic vesicles in root-tip cells was impaired in atann3-1 seedlings. Based on these results, we suggest that AtANN3 may be involved in eATP-regulated seedling growth by regulating the distribution of auxin and auxin transporters in vegetative organs.

15.
Plant Physiol ; 156(3): 1375-85, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21562328

RESUMO

Extracellular purine nucleotides are implicated in the control of plant development and stress responses. While extracellular ATP is known to activate transcriptional pathways via plasma membrane (PM) NADPH oxidase and calcium channel activation, very little is known about signal transduction by extracellular ADP. Here, extracellular ADP was found to activate net Ca(2+) influx in roots of Arabidopsis (Arabidopsis thaliana) and transiently elevate cytosolic free Ca(2+) in root epidermal protoplasts. An inward Ca(2+)-permeable conductance in root epidermal PM was activated within 1 s of ADP application and repeated application evoked a smaller current. Such response speed and densitization are consistent with operation of equivalents to animal ionotropic purine receptors, although to date no equivalent genes for such receptors have been identified in higher plants. In contrast to ATP, extracellular ADP did not evoke accumulation of intracellular reactive oxygen species. While high concentrations of ATP caused net Ca(2+) efflux from roots, equivalent concentrations of ADP caused net influx. Overall the results point to a discrete ADP signaling pathway, reliant on receptor-like activity at the PM.


Assuntos
Difosfato de Adenosina/farmacologia , Arabidopsis/metabolismo , Membrana Celular/metabolismo , Espaço Extracelular/metabolismo , Epiderme Vegetal/metabolismo , Raízes de Plantas/metabolismo , Receptores de Superfície Celular/metabolismo , Trifosfato de Adenosina/farmacologia , Arabidopsis/efeitos dos fármacos , Cálcio/metabolismo , Membrana Celular/efeitos dos fármacos , Espaço Extracelular/efeitos dos fármacos , Espaço Intracelular/efeitos dos fármacos , Espaço Intracelular/metabolismo , Ativação do Canal Iônico/efeitos dos fármacos , Epiderme Vegetal/efeitos dos fármacos , Raízes de Plantas/efeitos dos fármacos , Potássio/metabolismo , Protoplastos/efeitos dos fármacos , Protoplastos/metabolismo , Espécies Reativas de Oxigênio/metabolismo
16.
PeerJ ; 10: e14328, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36340202

RESUMO

The surface wax of fruit has a significant effect on abiotic stress and fruit quality. In this study, the composition of the waxes found on fruit surfaces and the related gene expression of three different pear cultivars (Xuehua, Yali, and Yuluxiang) were investigated during cold storage. The results showed that 35 wax compositions were found on the surfaces of the three pear cultivars, mainly including C29 alkane, three fatty acids, two esters, three aldehydes, three fatty alcohols, and three triterpenoids. The largest amount of C29 alkane, three fatty acids and two esters were found in Yuluxiang (YLX) on day 90, while aldehydes with carbons of C30 and C32 were the highest in Yali (YL). Xuehua (XH) showed the largest amount of C22 fatty alcohol on day 180 compared to YLX and YL. Larger amounts of triterpenoids were found in XH and YL when compared to YLX. The expression levels of fifteen wax related genes (LACS1, KCS2, KCS6, FDH, KCS20, GL8, CER10, CER60, LTPG1, LTP4, ABCG12, CER1L, CAC3, CAC3L, and DGAT1L) reached their peak at day 45 in YLX, compared to XH and YL, their expression levels in YLX were higher to different degrees. These results suggest that the different expression patterns of wax-related genes may be closely related to the difference in wax compositions of the surface wax of three pear cultivars.


Assuntos
Pyrus , Triterpenos , Humanos , Frutas/genética , Pyrus/genética , População do Leste Asiático , Ceras/metabolismo , Ácidos Graxos/metabolismo , Aldeídos/metabolismo , Triterpenos/metabolismo , Álcoois Graxos/metabolismo , Alcanos/metabolismo , Ésteres/metabolismo , Expressão Gênica
17.
AoB Plants ; 14(1): plab075, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-35079328

RESUMO

Phototropism is an essential response in some plant organs and features several signalling molecules involved in either photo-sensing or post-sensing responses. Annexins are involved in regulating plant growth and its responses to various stimuli. Here, we provide novel data showing that two members of the Annexin family in Arabidopsis thaliana, AtANN1 and AtANN2, may be involved in the phototropism of etiolated hypocotyls. In wild type, unilateral blue light (BL) induced a strong phototropic response, while red light (RL) only induced a weak response. The responses of single- or double-null mutants of the two annexins, including atann1, atann2 and atann1/atann2, were significantly weaker than those observed in wild type, indicating the involvement of AtANN1 and AtANN2 in BL-induced phototropism. Unilateral BL induced asymmetric distribution of DR5-GFP and PIN3-GFP fluorescence in hypocotyls; notably, fluorescent intensity on the shaded side was markedly stronger than that on the illuminated side. In etiolated atann1, atann2 or atann1/atann2 hypocotyls, unilateral BL-induced asymmetric distributions of DR5-GFP and PIN3-GFP were weakened or impaired. Herein, we suggest that during hypocotyls phototropic response, AtANN1 and AtANN2 may be involved in BL-stimulated signalling by regulating PIN3-charged auxin transport.

18.
Plant J ; 63(6): 1042-53, 2010 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-20626657

RESUMO

Spermidine (Spd) has been correlated with various physiological and developmental processes in plants, including pollen tube growth. In this work, we show that Spd induces an increase in the cytosolic Ca(2+) concentration that accompanies pollen tube growth. Using the whole-cell patch clamp and outside-out single-channel patch clamp configurations, we show that exogenous Spd induces a hyperpolarization-activated Ca(2+) current: the addition of Spd cannot induce the channel open probability increase in excised outside-out patches, indicating that the effect of Spd in the induction of Ca(2+) currents is exerted via a second messenger. This messenger is hydrogen peroxide (H2O2), and is generated during Spd oxidation, a reaction mediated by polyamine oxidase (PAO). These reactive oxygen species trigger the opening of the hyperpolarization-activated Ca(2+) -permeable channels in pollen. To provide further evidence that PAO is in fact responsible for the effect of Spd on the Ca(2+) -permeable channels, two Arabidopsis mutants lacking expression of the peroxisomal-encoding AtPAO3 gene, were isolated and characterized. Pollen from these mutants was unable to induce the opening of the Ca(2+) -permeable channels in the presence of Spd, resulting in reduced pollen tube growth and seed number. However, a high Spd concentration triggers a Ca(2+) influx beyond the optimal, which has a deleterious effect. These findings strongly suggest that the Spd-derived H2O2 signals Ca(2+) influx, thereby regulating pollen tube growth.


Assuntos
Canais de Cálcio/metabolismo , Membrana Celular/metabolismo , Canais de Cátion Regulados por Nucleotídeos Cíclicos/metabolismo , Peróxido de Hidrogênio/metabolismo , Oxirredutases atuantes sobre Doadores de Grupo CH-NH/metabolismo , Tubo Polínico/metabolismo , Pólen/metabolismo , Canais de Potássio/metabolismo , Canais Disparados por Nucleotídeos Cíclicos Ativados por Hiperpolarização , Microscopia de Fluorescência , Oxirredutases atuantes sobre Doadores de Grupo CH-NH/genética , Técnicas de Patch-Clamp , Tubo Polínico/crescimento & desenvolvimento , Espermidina/metabolismo , Poliamina Oxidase
19.
New Phytol ; 189(4): 1060-1068, 2011 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-21133925

RESUMO

• The regulation of plant potassium (K+) channels has been extensively studied in various systems. However, the mechanism of their regulation in the pollen tube is unclear. • In this study, the effects of heme and carbon monoxide (CO) on the outward K+ (K+(out)) channel in pear (Pyrus pyrifolia) pollen tube protoplasts were characterized using a patch-clamp technique. • Heme (1 µM) decreased the probability of K+(out) channel opening without affecting the unitary conductance, but this inhibition disappeared when heme was co-applied with 10 µM intracellular free Ca²+. Conversely, exposure to heme in the presence of NADPH increased channel activity. However, with tin protoporphyrin IX treatment, which inhibits hemeoxygenase activity, the inhibition of the K+(out) channel by heme occurred even in the presence of NADPH. CO, a product of heme catabolism by hemeoxygenase, activates the K+(out) channel in pollen tube protoplasts in a dose-dependent manner. The current induced by CO was inhibited by the K+ channel inhibitor tetraethylammonium. • These data indicate a role of heme and CO in reciprocal regulation of the K+(out) channel in pear pollen tubes.


Assuntos
Monóxido de Carbono/farmacologia , Heme/farmacologia , Ativação do Canal Iônico/efeitos dos fármacos , Pólen/metabolismo , Canais de Potássio Cálcio-Ativados/metabolismo , Pyrus/metabolismo , Germinação/efeitos dos fármacos , NADP/farmacologia , Pólen/efeitos dos fármacos , Tubo Polínico/efeitos dos fármacos , Tubo Polínico/crescimento & desenvolvimento , Protoplastos/efeitos dos fármacos , Protoplastos/metabolismo , Pyrus/efeitos dos fármacos
20.
Plant Signal Behav ; 16(11): 1976561, 2021 11 02.
Artigo em Inglês | MEDLINE | ID: mdl-34523390

RESUMO

Plants have evolved many leucine-rich repeat receptor-like kinases (LRR-RLKs) that control all aspects of plant life in a kinase-dependent or -independent manner. DROOPY LEAF1 (DPY1), which is a subfamily II LRR-RLK authentic kinase, controls leaf droopiness by negatively regulating early brassinosteroid (BR) signaling in foxtail millet. In this study, we proved that overexpressing kinase-inactive DPY1 does not rescue the droopy leaf phenotype of dpy1 plants because the mutated DPY1 cannot repress BR signaling, suggesting that kinase activity is required for DPY1 to control BR signaling. Moreover, seven DPY1 sites potentially transphosphorylated by SiBAK1 were identified as crucial for DPY1 activation. These findings highlight the importance of kinase activity for the functionality of DPY1.


Assuntos
Brassinosteroides/metabolismo , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/metabolismo , Proteínas Quinases/metabolismo , Setaria (Planta)/crescimento & desenvolvimento , Setaria (Planta)/genética , Setaria (Planta)/metabolismo , Produtos Agrícolas/genética , Produtos Agrícolas/crescimento & desenvolvimento , Produtos Agrícolas/metabolismo , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Variação Genética , Genótipo , Folhas de Planta/genética , Proteínas Quinases/genética
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