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Results for “PLANT HORMONES”

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At least 253 records · Page 14Linked to original sources
PubMed1991

Putative receptor for the plant growth hormone auxin identified and characterized by anti-idiotypic antibodies.

The molecular mechanism of action of auxins, which are an important class of plant growth regulators, is not known. While they are thought to influence cellular processes such as gene expression and membrane hyperpolarization by binding to specific receptors, no receptor mediating these processes has been unambiguously identified. We describe the identification of a putative auxin receptor by using anti-idiotypic antibodies. We have demonstrated that a 65-kilodalton protein found in a wide range of plants specifically binds auxins. Furthermore, since it is localized to the nucleus, it is a candidate for an auxin receptor that mediates some nuclear process.

Journal Article↗
PubMed2003

Genetic approaches to understanding sugar-response pathways.

Plants as photoautotrophic organisms are able to produce the carbohydrates they require and have developed mechanisms to co-ordinate carbohydrate production and its metabolism. Carbohydrate-derived signals regulate the expression of genes involved in both photosynthesis and metabolism, and control carbohydrate partitioning. A number of genetic approaches have been initiated to understand sugar-response pathways in plants and identify the components involved. Screening strategies to date have been based on the effects of high sugar media on early seedling development or on changes in the enzyme activity or expression of sugar-responsive genes. These screens have established roles for plant hormones in sugar-response pathways, in particular for abscisic acid. The present emphasis on the role of plant hormones in sugar responses is due to the fact that mutants could be readily identified as belonging to these established pathways, but also results from the nature of the mutant screens in use. Progress is being made on the identification of mutants and genes that may be specific to sugar-signalling pathways. It is also expected that the modification of existing screens may target sugar-signalling pathways more directly. Genetic approaches may be especially useful in identifying components of novel signalling pathways unique to plants, and their combination with genomic and molecular approaches will guide future research.

Abscisic Acid↗
PubMed2001

Plant peptide hormones: The long and the short of it.

A polypeptide from tobacco has been found to be processed into multiple functional peptides, each with independent hormone-like activities. This adds to a growing set of small peptides known to function as signal molecules in plants.

Animals↗
PubMed2026

Systematic identification pepper CaE2F transcription factor reveals the role of CaDPb in drought stress response.

The EARLY 2 FACTOR (E2F) transcription factor (TF) family plays a pivotal role in regulating plant development and adaptations to environmental stresses. However, the physiological function of E2Fs in pepper (Capsicum annuum L.) are not well elucidated. In this work, we conduct a comprehensive genome-wide annotation of the E2F family within the Zunla-1 pepper genome and further explore the biological roles of CaDPb in response to drought stress. Through systematic bioinformatics analysis, we identify a total of nine CaE2F genes within the Zunla-1 genome, categorizing them into three distinct subgroups. Additionally, we discover multiple cis-regulatory elements in the CaE2F promoter regions associated with responses to plant hormones and drought stress. Public RNA-seq datasets reveal distinct expression profiles of CaE2F genes across various pepper tissues and their responses to environmental stimuli and plant hormones. Subsequently, the CaDPb gene is further functionally verified in drought response. Our findings indicate that TRV2:CaDPb silenced pepper plants are more sensitivity to drought. Furthermore, we show that CaDPb participates in the regulation of reactive oxygen species (ROS) production, the expression of drought-responsive genes, and the modulation of stomatal aperture. Taken together, our findings provide a comprehensive characterization of E2F genes in pepper and offer insights into the biological function of CaDPb in pepper drought stress response.

Capsicum↗
PubMed2004

Auxin regulation of cytokinin biosynthesis in Arabidopsis thaliana: a factor of potential importance for auxin-cytokinin-regulated development.

One of the most long-lived models in plant science is the belief that the long-distance transport and ratio of two plant hormones, auxin and cytokinin, at the site of action control major developmental events such as apical dominance. We have used in vivo deuterium labeling and mass spectrometry to investigate the dynamics of homeostatic cross talk between the two plant hormones. Interestingly, auxin mediates a very rapid negative control of the cytokinin pool by mainly suppressing the biosynthesis via the isopentenyladenosine-5'-monophosphate-independent pathway. In contrast, the effect of cytokinin overproduction on the entire auxin pool in the plant was slower, indicating that this most likely is mediated through altered development. In addition, we were able to confirm that the lateral root meristems are likely to be the main sites of isopentenyladenosine-5'-monophosphate-dependent cytokinin synthesis, and that the aerial tissue of the plant surprisingly also was a significant source of cytokinin biosynthesis. Our demonstration of shoot-localized synthesis, together with data demonstrating that auxin imposes a very rapid regulation of cytokinin biosynthesis, illustrates that the two hormones can interact also on the metabolic level in controlling plant development, and that the aerial part of the plant has the capacity to synthesize its own cytokinin independent of long-range transport from the root system.

Adenosine Monophosphate↗
PubMed1997

Jasmonic acid-dependent and -independent signaling pathways control wound-induced gene activation in Arabidopsis thaliana.

Plant response to mechanical injury includes gene activation both at the wound site and systemically in nondamaged tissues. The model developed for the wound-induced activation of the proteinase inhibitor II (Pin2) gene in potato (Solanum tuberosum) and tomato (Lycopersicon esculentum) establishes the involvement of the plant hormones abscisic acid and jasmonic acid (JA) as key components of the wound signal transduction pathway. To assess in Arabidopsis thaliana the role of these plant hormones in regulating wound-induced gene expression, we isolated wound- and JA-inducible genes by the differential mRNA display technique. Their patterns of expression upon mechanical wounding and hormonal treatments revealed differences in the spatial distribution of the transcripts and in the responsiveness of the analyzed genes to abscisic acid and JA. A correlation can be established between sensitivity to JA and the accumulation of the transcripts in systemic tissues upon wounding. A comparative study of the wound response in wild-type and JA-insensitive coi1 mutant plants indicated that in A. thaliana wound signals are transmitted via at least two different pathways. One of them does not involve JA as a mediator and is preferentially responsible for gene activation in the vicinity of the wound site, whereas the other requires JA perception and activates gene expression throughout the aerial part of the plant.

Arabidopsis↗
PubMed2001

Isolation and properties of arginase from a shade plant, ginseng (Panax ginseng C.A. Meyer) roots.

Arginase (EC 3.5.3.1) was purified to homogeneity from root tissues of three-year-old ginseng (Panax ginseng C.A. Meyer), shade plant, and was found to be an extraordinarily large molecule relatively stable to heat. The enzyme was decameric having a molecular mass of 352,000 Da, with an optimal temperature and pH of 60 degrees C and 9.5, respectively. Analogues of arginine could not replace it as substrate, and a cysteine residue is at or near the active site. Maximum activity was obtained with Mn(2+) and Co(2+) also activated the proteins, whereas, both agmatine and 5'-deoxy-methylthioadenosine were inhibitors. Specific activities of the enzyme in sliced ginseng roots were increased by plant hormones such as GA(3), IAA, kinetin and putrescine, whereas the activities of the purified enzyme were unaffected by putrescine. Increases in arginase activities by these plant hormones could affect metabolism of polyamine intracellularly.

Agmatine↗
PubMed1983

Plant steroid hormones.

After a brief survey of the literature on the recently discovered brassinolide, some of our results with corticosteroids are given. A number of structural requirements of corticosteroids were deduced in a bioassay involving elongation growth and lateral root formation. To explain the activity of glucocorticoids, the involvement of a receptor protein is suggested as well as an enhanced RNA synthesis. However, the structural requirements found are not applicable to experiments on adventitious root formation, implying a different mode of action of corticosteroids in this test system.

Adrenal Cortex Hormones↗
PubMed2005

Induction of heat shock protein 72 in C6 glioma cells by methyl jasmonate through ROS-dependent heat shock factor 1 activation.

Salicylate and jasmonates are two different types of plant hormone that play critical roles in plant defense responses against insect herbivores and microbial pathogens, through activating defense genes. These two natural products have been shown to have similar activities in animal cells: the compounds are able to induce cell cycle arrest or apoptosis in a variety of human cancer cells including those of colon, prostate, breast, and leukemia, suggesting the chemicals may potentially be a novel class of anti-cancer drugs. Since sodium salicylate can induce the heat shock response in animals, we examined the effects of jasmonates on the heat shock response in C6 glioma cells. Here, we show that brief exposure to methyl jasmonate (MeJA), but not to jasmonic acid, induces heat shock protein 72 (HSP72), but not HSP73 and HSP90, via heat shock factor I (HSF1) activation in C6 glioma cells without affecting cell viability. Intracellular H2O2 and O2-, and mitochondrial ROS were prominently increased in response to 5 mM MeJA in C6 cells. MeJA-induced HSP72 expression, HSF1 DNA binding, and human HSP70 promoter-driven CAT activity were prevented by N-acetyl-L-cysteine (a general antioxidant), catalase (a specific antioxidant for H2O2), and sodium formate (an inhibitor of OH.), but not by Rac1 dominant negative mutant Rac1N17 and diphenyleneiodonium (a NADPH oxidase inhibitor), indicating that MeJA induces HSP72 expression though HSF1 that is activated via Rac1-NADPH oxidase-independent ROS production pathway. These results suggest that the plant stress hormones share the ability to induce heat shock response in animal cells.

Acetates↗
PubMed2005

G protein signaling in the regulation of Arabidopsis seed germination.

Seed germination and early seedling growth are regulated by an intricate network of hormonal signaling pathways. The plant hormones gibberellic acid (GA) and brassinosteroids (BRs) are important positive regulators of these processes, whereas the hormone abscisic acid (ABA) is a potent negative regulator. In Arabidopsis, analysis of mutant plants has implicated heterotrimeric guanine nucleotide-binding protein (G protein) components in regulation of seed germination by all three of these hormones.

Abscisic Acid↗
PubMed2000

Promoter analysis of pyk20, a gene from Arabidopsis thaliana.

The gene pyk20 which has been isolated from Arabidopsis thaliana encodes a protein with a glutamine-rich domain in the C-terminal region. The transcription of this gene was shown to be induced in feeding sites of root-parasitic nematodes (Heterodera schachtii), in roots infected by a fungus-like organism (Plasmodiophora brassicae), by plant hormone treatment, and by wounding. In order to identify functional promoter regions seven different 5' and 3' pyk20 promoter (ppyk20) deletion fragments were fused to the uidA gene (gus) and transformed into A. thaliana plants. Histochemical analysis of plants containing the different ppyk20::uidA reporter constructs was performed during plant development in different plant tissues. Comparison of the promoter deletion constructs showed that the region between -277 and -1 bp is necessary to enhance the level of the GUS expression in nematode feeding sites and by plant hormone treatment. The region between -1912 and -278 is essential to provide specificity of GUS expression. Conserved regulatory elements were identified in the ppyk20 by sequence analysis. The activation pattern of ppyk20 makes it well suited to engineer resistance against nematodes and other pathogens.

Journal Article↗