共查询到20条相似文献,搜索用时 8 毫秒
1.
The ATPases associated with various cellular activities (AAA) proteins are widespread in living organisms. Some of the AAA-type
ATPases possess metalloprotease activities. Other members constitute the 26S proteasome complexes. In recent years, a few
AAA members have been implicated in vesicle-mediated secretion, membrane fusion, cellular organelle biogenesis, and hypersensitive
responses (HR) in plants. However, the physiological roles and biochemical activities of plant AAA proteins have not yet been
defined at the molecular level, and regulatory mechanisms underlying their functions are largely unknown. In this study, we
showed that overexpression of an Arabidopsis gene encoding a mitochondrial AAA protein, ATPase-in-Seed-Development (ASD), induces morphological and anatomical defects
in seed maturation. The ASD gene is expressed at a high level during the seed maturation process and in mature seeds but is repressed rapidly in germinating
seeds. Transgenic plants overexpressing the ASD gene are morphologically normal. However, seed formation is severely disrupted in the transgenic plants. The ASD gene is
induced by abiotic stresses, such as low temperatures and high salinity, in an abscisic acid (ABA)-dependent manner. The ASD
protein possesses ATPase activity and is localized into the mitochondria. Our observations suggest that ASD may play a role
in seed maturation by influencing mitochondrial function under abiotic stress. 相似文献
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To ensure that the initiation of flowering occurs at the correct time of year, plants need to integrate a diverse range of
external and internal signals. In Arabidopsis, the photoperiodic flowering pathway is controlled by a set of regulators that include CONSTANS (CO). In addition, Arabidopsis plants also have a family of genes with homologies to CO known as CO-LIKE (COL) about which relatively little is known. In this paper, we describe the regulation and interactions of a novel member of
the family, COL5. The expression of COL5 is under circadian and diurnal regulation, but COL5 itself does not appear to affect circadian rhythms. COL5, like CO, is regulated by GIGANTEA. Furthermore, COL5 is expressed in the vascular tissue. Using COL5 over-expressing lines we show that, under short days, constitutive expression of COL5 affects flowering time and the expression of the floral integrator genes, FLOWERING LOCUS T and SUPPRESSOR OF OVEREXPRESSION OF CO 1. Constitutive expression of COL5 partially suppresses the late flowering phenotype of the co-mutant plants. However, plants with loss of COL5 function do not show altered flowering. Taken together, our results suggest that COL5 has COL activity, but may either not
have a role in regulating flowering in wild-type plants or may act redundantly with other flowering regulators.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
4.
T. Zhang 《In vitro cellular & developmental biology. Plant》2007,43(2):91-94
This study investigated the factors affecting in vitro flowering of Perilla frutescens. The shoots regenerated from cotyledonary and hypocotyl explants cultured on Murashige and Skoog (MS) medium supplemented
with benzyladenine (BA) and indole-3-acetic acid, each at 0.5 mg l−1, were excised and transferred to MS medium containing 30 g l−1 of sucrose, 8.25 g l−1 of ammonium nitrate, and 1.0 mg l−1 of BA. After 40 d of culture, 86.2% of shoots flowered and most of which self-fertilized in vitro and produced mature fruits with viable seeds. These seeds were germinated and plants were grown to maturity and flowered
in soil under greenhouse conditions. The in vitro flowering system reported in this study may facilitate rapid breeding of P. frutescens and offers a model system for studying the physiological mechanism of flowering. 相似文献
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Ubiquitination is a unique protein degradation system utilized by eukaryotes to efficiently degrade detrimental cellular proteins
and control the entire pool of regulatory components. In plants, adaptation in response to various abiotic stresses can be
achieved through ubiquitination and the resulting degradation of components specific to these stress signalings. Arabidopsis has more than 1,400 E3 enzymes, indicating E3 ligase acts as a main determinant of substrate specificity. However, as only
a minority of E3 ligases related to abiotic stress signaling have been studied in Arabidopsis, the further elucidation of the biological roles and related substrates of newly identified E3 ligases is essential in order
to clarify the functional relationship between abiotic stress and E3 ligases. Here, we review the current knowledge and future
prospects of the regulatory mechanism and role of several E3 ligases involved in abiotic stress signal transduction in Arabidopsis. As another potential approach to understand how ubiquitination is involved in such signaling, we also briefly introduce
factors that regulate the activity of cullin in multisubunit E3 ligase complexes. 相似文献
8.
The miR166/165 group and its target genes regulate diverse aspects of plant development, including apical and lateral meristem
formation, leaf polarity, and vascular development. We demonstrate here that MIR166/165 genes are dynamically controlled in regulating shoot apical meristem (SAM) and floral development in parallel to the WUSCHEL (WUS)-CLAVATA (CLV) pathway. Although miR166 and miR165 cleave same target mRNAs, individual MIR166/165 genes exhibit distinct expression domains in different plant tissues. The MIR166/165 expression is also temporarily regulated. Consistent with the dynamic expression patterns, an array of alterations in SAM
activities and floral architectures was observed in the miR166/165-overproducing plants. In addition, when a MIR166a-overexpressing mutant was genetically crossed with mutants defective in the WUS-CLV pathway, the resultant crosses exhibited additive phenotypic effects, suggesting that the miR166/165-mediated signal exerts
its role via a distinct signaling pathway. 相似文献
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HrpN, a protein produced by the plant pathogenic bacterium Erwinia amylovora, has been shown to stimulate plant growth and resistance to pathogens and insects. Here we report that HrpN activates abscisic acid (ABA) signalling to induce drought tolerance (DT) in Arabidopsis thaliana L. plants grown with water stress. Spraying wild-type plants with HrpN-promoted stomatal closure decreased leaf transpiration rate, increased moisture and proline levels in leaves, and alleviated extents of damage to cell membranes and plant drought symptoms caused by water deficiency. In plants treated with HrpN, ABA levels increased; expression of several ABA-signalling regulatory genes and the important effector gene rd29B was induced or enhanced. Induced expression of rd29B, promotion of stomatal closure, and reduction in drought severity were observed in the abi1-1 mutant, which has a defect in the phosphatase ABI1, after HrpN was applied. In contrast, HrpN failed to induce these responses in the abi2-1 mutant, which is impaired in the phosphatase ABI2. Inhibiting wild-type plants to synthesize ABA eliminated the role of HrpN in promoting stomatal closure and reducing drought severity. Moreover, resistance to Pseudomonas syringae developed in abi2-1 as in wild-type plants following treatment with HrpN. Thus, an ABI2-dependent ABA signalling pathway is responsible for the induction of DT but does not affect pathogen defence under the circumstances of this study.Hong-Ping Dong and Haiqin Yu contributed equally to this study and are regarded as joint first authors. 相似文献
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Matthew A. Jones 《Journal of Plant Biology》2009,52(3):202-209
The rising and setting of the sun marks a transition between starkly contrasting environmental conditions for vegetative life.
Given these differing diurnal and nocturnal environmental factors and the inherent regularity of the transition between the
two, it is perhaps unsurprising that plants have developed an internal timing mechanism (known as a circadian clock) to allow
modulation of gene expression and metabolism in response to external cues. Entrainment of the circadian clock, primarily via
the detection of changes in light and temperature, maintains synchronization between the surrounding environment and the endogenous
clock mechanism. In this review, recent advances in our understanding of the molecular workings of the plant circadian clock
are discussed as are the input pathways necessary for entrainment of the clock machinery. 相似文献
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Complex signal transduction pathways underlie the myriad plant responses to attack by pathogens. Ca2+ is a universal second messenger in eukaryotes that modulates various signal transduction pathways through stimulus-specific
changes in its intracellular concentration. Ca2+-binding proteins such as calmodulin (CaM) detect Ca2+ signals and regulate downstream targets as part of a coordinated cellular response to a given stimulus. Here we report the
characterization of a tomato gene (APR134) encoding a CaM-related protein that is induced in disease-resistant leaves in response to attack by Pseudomonas syringae pv. tomato. We show that suppression of APR134 gene expression in tomato (Solanum lycopersicum), using virus-induced gene silencing (VIGS), compromises the plant’s immune response. We isolated APR134-like genes from Arabidopsis, termed CML42 and CML43, to investigate whether they serve a functionally similar role. Gene expression analysis revealed that CML43 is rapidly induced in disease-resistant Arabidopsis leaves following inoculation with Pseudomonas syringae pv. tomato. Overexpression of CML43 in Arabidopsis accelerated the hypersensitive response. Recombinant APR134, CML42, and CML43 proteins all bind Ca2+ in vitro. Collectively, our data support a role for CML43, and APR134 as important mediators of Ca2+-dependent signals during the plant immune response to bacterial pathogens.
This work was supported by a research grant (WAS) and postgraduate scholarships (DC, SLD) from the Natural Science and Engineering
Research Council of Canada, the National Science Foundation (IBN-0109633; GBM), and the Swedish Research Council (SKE). 相似文献
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The FT/TFL1 gene family encodes proteins with similarity to phosphatidylethanolamine binding proteins which function as flowering promoters
and repressors. We show here that the FT/TFL1 gene family in Vitis vinifera is composed of at least five genes. Sequence comparisons with homologous genes identified in other dicot species group them
in three major clades, the FT, MFT and TFL1 subfamilies, the latter including three of the Vitis sequences. Gene expression patterns are in agreement with a role of VvFT and VvMFT as flowering promoters; while VvTFL1A, VvTFL1B and VvTFL1C could be associated with vegetative development and maintenance of meristem indetermination. Overexpression of VvFT in transgenic Arabidopsis plants generates early flowering phenotypes similar to those produced by FT supporting a role for this gene in flowering promotion. Overexpression of VvTFL1A does not affect flowering time but the determination of flower meristems, strongly altering inflorescence structure, which
is consistent with the biological roles assigned to similar genes in other species. 相似文献
18.
Kexue Li Youning Wang Chunyu Han Wensheng Zhang Huizhen Jia Xia Li 《Plant Growth Regulation》2007,53(3):195-206
Flowering timing is very important for the reproductive success of higher plants. However, effects of salt on plant flowering
and the underlying molecular mechanisms are largely unknown. Here, we show that salt stress delays flowering in Arabidopsis in a dose-dependent manner. Mild salt stress (≤50 mM NaCl) promoted and prolonged the vegetative growth, whereas high salinity
(≥100 mM NaCl) largely delayed or inhibited the transition from vegetative growth to reproductive development. The gibberellin
(GA)-pathway plays an important role in this phenotype, and application of exogenous GA could restore late flowering induced
by salt. In addition, the CONSTANS (CO)/FLOWERING LOCUS T (FT) module may also play a critical role in mediating the effects of salt on flowering. The mRNA abundance of CO was significantly reduced by salt stress in a dose-dependent manner. The constans (co-2) mutants did not respond to moderate salt stress, whereas over-expressing CO manifested no delay in flowering time in response to salinity. Expression of FT, SOC1 and LFY in the downstream of the pathways was also reduced by salt according to dose. Moreover, salt-sensitive mutant salt overly sensitive3 (sos3) exhibited greater sensitivity in flowering, further suggesting that ion disequilibrium mediates salt-induced late flowering.
Kexue Li and Youning Wang contributed equally to this report. 相似文献
19.
Two cDNAs isolated from Cymodocea nodosa, CnSOS1A, and CnSOS1B encode proteins with high-sequence similarities to SOS1 plant transporters. CnSOS1A expressed in a yeast Na+-efflux mutant under the control of a constitutive expression promoter mimicked AtSOS1 from Arabidopsis; the wild type cDNA did not improve the growth of the recipient strain in the presence of Na+, but a cDNA mutant that expresses a truncated protein suppressed the defect of the yeast mutant. In similar experiments,
CnSOS1B was not effective. Conditional expression, under the control of an arabinose responsive promoter, of the CnSOS1A and CnSOS1B cDNAs in an Escherichia coli mutant defective in Na+ efflux was toxic, and functional analyses were inconclusive. The same constructs transformed into an E. coli K+-uptake mutant revealed that CnSOS1A was also toxic, but that it slightly suppressed defective growth at low K+. Truncation in the C-terminal hydrophilic tail of CnSOS1A relieved the toxicity and proved that CnSOS1A was an excellent
low-affinity K+ and Rb+ transporter. CnSOS1B mediated a transient, extremely rapid K+ or Rb+ influx. Similar tests with AtSOS1 revealed that it was not toxic and that the whole protein exhibited excellent K+ and Rb+ uptake characteristics in bacteria. 相似文献
20.
Using a cDNA-array we identified expressed sequence tag 163B24T7 as rapidly up-regulated in Arabidopsis thaliana (L.) Heynh. after pathogen exposure. Detailed expression analysis revealed that the corresponding gene is up-regulated not only after exposure to avirulent Pseudomonas syringae pv. tomato but also to virulent strains. This up-regulation is dependent on functional salicylic acid defence-signalling pathways. Moreover, we found the gene was circadian-regulated, showing peaks of expression at the end of the day. Using plants overexpressing the clock component CCA1, we showed that the PCC1 gene is regulated by the inner clock of Arabidopsis. Accordingly, we named the gene PCC1, for pathogen and circadian controlled. PCC1 is a member of a novel family of six small polypeptides in Arabidopsis. A functional role for PCC1 in plant defence was demonstrated since plants overexpressing PCC1 are resistant against normally virulent oomycetes. Thus, PCC1 demonstrates a potential interrelationship between pathogen and circadian signalling pathways.Abbreviations
cfu
Colony-forming units
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EST
Expressed sequence tag
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Pst
Pseudomonas syringae pv. tomato
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TAIR
The Arabidopsis information resource 相似文献