Termínem gibberellin-regulated proteins je označována skupina alergenů zkoumaná v posledních letech v souvislosti se zkříženými pylově potravinovými alergiemi (pollen/food allergy syndrome). Gibereliny jsou skupinou fytohormonů figurující v ochraně rostlin, mají baktericidní, virucidní a fungicidní účinky. Fungují jako růstové hormony a vylučují se při zrání, ale i při stresu rostlin. Jedná se o antimikrobiální peptidy o molekulové hmotnosti 7–8 kDa bohaté na cystein, jejichž struktura je obdobná v celé řadě vyšších rostlin. Díky vysokému obsahu cysteinu jsou termostabilní a acidorezistentní, proto jsou považovány za rizikové potravinové alergeny, schopné vyvolat závažné alergické reakce. Klinické projevy potravinové alergie na gibberellin-regulated proteiny jsou poměrně charakteristické, jsou jimi otok obličeje (zvláště očních víček) a laryngeální otok. Alergické reakce bývají se závažnějším průběhem zvláště tehdy, pokud jsou přítomny další faktory (tělesná náma- ha, léčba nesteroidními antiflogistiky, inhibitory proteinové pumpy, vliv alkoholu, infekce, menstruace apod.). Dosud bylo identifikováno 9 těchto alergenních proteinů různých rostlinných zdrojů pylových Cry j 7, Cup s 7, Jun a 7, potravinových Pru p 7, Pru m 7, Pun g 7, Cit s 7, Pru av 7, Cap a 7. Byly popsány i dvě nealergenní molekuly – applemaclein, snakin-1. K primární senzibilizaci dochází nejspíše prostřednictvím inhalační alergie na pyl cypřišovitých.
Gibberellin-regulated proteins are a group of allergens investigated in recent years in relation with pollen/food allergy syndrome. Gibberellins are a group of phytohormones, which play role in plant protection, have bactericidal, virucidal and fungicidal effects, function as growth hormones and are secreted during ripening process, but also during plant stress. These proteins are antimicrobial peptides with a molecular weight of 7–8 kDa, rich in cysteine, which stucture is very conserved across a wide number of higher plants. Due to their high cysteine content, they are thermostable and acidoresistant, which is why they are considered as a risky food allergens capable of causing serious allergic reactions. Clinical symptoms of gibberellin-regulated proteins allergy are quite characteristic, including facial swelling (especially eyelid oedema) a laryngeal tightness. Allergic reactions to GRPs tend to be more severe, especially if co-factors are present (exercise, nonsteroid – antiinflammatory drugs or proton pump inhibitors therapy, alcohol, infection, menstruation and others). So far 9 allergenic gibberellin-regulated proteins have been identified from different plant sources pollen Cry j 7, Cup s 7, Jun a 7 and food Pru p 7, Pru m 7, Pun g 7, Cit s 7, Pru av 7, Cap a 7 and 2 non-allergenic applemaclein, snakin-1. Most probably primary sensitization occurs through inha- lation allergy to cypress pollen.
Studies of vitality/mortality of cortex cells, as well as of the concentrations of ethylene (ETH), gibberellins (GAs), indolic compounds/auxins (ICs/AUXs) and cytokinins (CKs), were undertaken to explain the hormonal background of kinetin (Kin)-regulated cell death (RCD), which is induced in the cortex of the apical parts of roots of faba bean (Vicia faba ssp. minor) seedlings. Quantification was carried out with fluorescence microscopy, ETH sensors, spectrophotometry and ultrahigh-performance liquid chromatography tandem mass spectrometry (UHPLC‒MS/MS). The results indicated that Kin was metabolized to the transport form, i.e., kinetin-9-glucoside (Kin9G) and kinetin riboside (KinR). KinR was then converted to cis-zeatin (cZ) in apical parts of roots with meristems, to cis-zeatin riboside (cZR) in apical parts of roots without meristems and finally to cis-zeatin riboside 5'-monophosphate (cZR5'MP), which is indicated to be a ligand of cytokinin-dependent receptors inducing CD. The process may be enhanced by an increase in the amount of dihydrozeatin riboside (DHZR) as a byproduct of the pathway of zeatin metabolism. It seems that crosstalk of ETH, ICs/AUXs, GAs and CKs with the cZR5'MP, the cis-zeatin-dependent pathway, but not the trans-zeatin-dependent pathway, is responsible for Kin-RCD, indicating that the process is very specific and offers a useful model for studies of CD hallmarks in plants.
The NGATHA (NGA) transcription factor (TF) belongs to the ABI3/VP1 (RAV) transcriptional subfamily, a subgroup of the B3 superfamily, which is relatively well-studied in Arabidopsis. However, limited data are available on the contributions of NGA TF in other plant species. In this study, 207 NGA gene family members were identified from a genome-wide search against Arabidopsis thaliana in the genome data of 18 dicots and seven monocots. The phylogenetic and sequence alignment analyses divided NGA genes into different clusters and revealed that the numbers of genes varied depending on the species. The phylogeny was followed by the characterization of the Solanaceae (tomato, potato, capsicum, tobacco) and Poaceae (Brachypodium distachyon, Oryza sativa L. japonica, and Sorghum bicolor) family members in comparison with A. thaliana. The gene and protein structures revealed a similar pattern for NGA and NGA-like sequences, suggesting that both are conserved during evolution. Promoter cis-element analysis showed that phytohormones such as abscisic acid, auxin, and gibberellins play a crucial role in regulating the NGA gene family. Gene ontology analysis revealed that the NGA gene family participates in diverse biological processes such as flower development, leaf morphogenesis, and the regulation of transcription. The gene duplication analysis indicates that most of the genes are evolved due to segmental duplications and have undergone purifying selection pressure. Finally, the gene expression analysis implicated that the NGA genes are abundantly expressed in lateral organs and flowers. This analysis has presented a detailed and comprehensive study of the NGA gene family, providing basic knowledge of the gene, protein structure, function, and evolution. These results will lay the foundation for further understanding of the role of the NGA gene family in various plant developmental processes.
- MeSH
- Arabidopsis * genetics metabolism MeSH
- Brachypodium * genetics MeSH
- Phylogeny MeSH
- Genome, Plant MeSH
- Multigene Family MeSH
- Gene Expression Regulation, Plant MeSH
- Plant Proteins genetics metabolism MeSH
- Oryza * genetics metabolism MeSH
- Transcription Factors genetics metabolism MeSH
- Publication type
- Journal Article MeSH
Improving yield, nutritional value and tolerance to abiotic stress are major targets of current breeding and biotechnological approaches that aim at increasing crop production and ensuring food security. Metabolic engineering of carotenoids, the precursor of vitamin-A and plant hormones that regulate plant growth and response to adverse growth conditions, has been mainly focusing on provitamin A biofortification or the production of high-value carotenoids. Here, we show that the introduction of a single gene of the carotenoid biosynthetic pathway in different tomato cultivars induced profound metabolic alterations in carotenoid, apocarotenoid and phytohormones pathways. Alterations in isoprenoid- (abscisic acid, gibberellins, cytokinins) and non-isoprenoid (auxin and jasmonic acid) derived hormones together with enhanced xanthophyll content influenced biomass partitioning and abiotic stress tolerance (high light, salt, and drought), and it caused an up to 77% fruit yield increase and enhanced fruit's provitamin A content. In addition, metabolic and hormonal changes led to accumulation of key primary metabolites (e.g. osmoprotectants and antiaging agents) contributing with enhanced abiotic stress tolerance and fruit shelf life. Our findings pave the way for developing a new generation of crops that combine high productivity and increased nutritional value with the capability to cope with climate change-related environmental challenges.
The plant-specific receptor-like cytoplasmic kinases (RLCKs) form a large, poorly characterized family. Members of the RLCK VI_A class of dicots have a unique characteristic: their activity is regulated by Rho-of-plants (ROP) GTPases. The biological function of one of these kinases was investigated using a T-DNA insertion mutant and RNA interference. Loss of RLCK VI_A2 function resulted in restricted cell expansion and seedling growth. Although these phenotypes could be rescued by exogenous gibberellin, the mutant did not exhibit lower levels of active gibberellins nor decreased gibberellin sensitivity. Transcriptome analysis confirmed that gibberellin is not the direct target of the kinase; its absence rather affected the metabolism and signalling of other hormones such as auxin. It is hypothesized that gibberellins and the RLCK VI_A2 kinase act in parallel to regulate cell expansion and plant growth. Gene expression studies also indicated that the kinase might have an overlapping role with the transcription factor circuit (PIF4-BZR1-ARF6) controlling skotomorphogenesis-related hypocotyl/cotyledon elongation. Furthermore, the transcriptomic changes revealed that the loss of RLCK VI_A2 function alters cellular processes that are associated with cell membranes, take place at the cell periphery or in the apoplast, and are related to cellular transport and/or cell wall reorganisation.
- MeSH
- Arabidopsis drug effects enzymology genetics growth & development MeSH
- DNA, Bacterial genetics metabolism MeSH
- DNA-Binding Proteins genetics metabolism MeSH
- Plants, Genetically Modified MeSH
- Gibberellins metabolism pharmacology MeSH
- Hypocotyl drug effects enzymology genetics growth & development MeSH
- Mutagenesis, Insertional MeSH
- Cotyledon drug effects enzymology genetics growth & development MeSH
- Indoleacetic Acids metabolism pharmacology MeSH
- Protein Serine-Threonine Kinases genetics metabolism MeSH
- Arabidopsis Proteins genetics metabolism MeSH
- Gene Expression Regulation, Plant * MeSH
- Plant Growth Regulators pharmacology MeSH
- Seedlings drug effects enzymology genetics growth & development MeSH
- Gene Expression Profiling MeSH
- Basic Helix-Loop-Helix Transcription Factors genetics metabolism MeSH
- Transcription Factors genetics metabolism MeSH
- Transcriptome MeSH
- Gene Expression Regulation, Developmental MeSH
- Publication type
- Journal Article MeSH
DELLA transcriptional regulators are central components in the control of plant growth responses to the environment. This control is considered to be mediated by changes in the metabolism of the hormones gibberellins (GAs), which promote the degradation of DELLAs. However, here we show that warm temperature or shade reduced the stability of a GA-insensitive DELLA allele in Arabidopsis thaliana Furthermore, the degradation of DELLA induced by the warmth preceded changes in GA levels and depended on the E3 ubiquitin ligase CONSTITUTIVELY PHOTOMORPHOGENIC1 (COP1). COP1 enhanced the degradation of normal and GA-insensitive DELLA alleles when coexpressed in Nicotiana benthamiana. DELLA proteins physically interacted with COP1 in yeast, mammalian, and plant cells. This interaction was enhanced by the COP1 complex partner SUPRESSOR OF phyA-105 1 (SPA1). The level of ubiquitination of DELLA was enhanced by COP1 and COP1 ubiquitinated DELLA proteins in vitro. We propose that DELLAs are destabilized not only by the canonical GA-dependent pathway but also by COP1 and that this control is relevant for growth responses to shade and warm temperature.
- MeSH
- Arabidopsis chemistry enzymology genetics metabolism MeSH
- Gibberellins metabolism MeSH
- Arabidopsis Proteins genetics metabolism MeSH
- Proteolysis MeSH
- Gene Expression Regulation, Plant MeSH
- Plant Growth Regulators metabolism MeSH
- Repressor Proteins genetics metabolism MeSH
- Protein Stability MeSH
- Ubiquitination MeSH
- Ubiquitin-Protein Ligases genetics metabolism MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Research Support, N.I.H., Extramural MeSH
Salicylic acid (SA) is a very simple phenolic compound (a C7H6O3 compound composed of an aromatic ring, one carboxylic and a hydroxyl group) and this simplicity contrasts with its high versatility and the involvement of SA in several plant processes either in optimal conditions or in plants facing environmental cues, including heavy metal (HM) stress. Nowadays, a huge body of evidence has unveiled that SA plays a pivotal role as plant growth regulator and influences intra- and inter-plant communication attributable to its methyl ester form, methyl salicylate, which is highly volatile. Under stress, including HM stress, SA interacts with other plant hormones (e.g., auxins, abscisic acid, gibberellin) and promotes the stimulation of antioxidant compounds and enzymes thereby alerting HM-treated plants and helping in counteracting HM stress. The present literature survey reviews recent literature concerning the roles of SA in plants suffering from HM stress with the aim of providing a comprehensive picture about SA and HM, in order to orientate the direction of future research on this topic.
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- Antioxidants metabolism MeSH
- Stress, Physiological MeSH
- Salicylic Acid chemistry metabolism MeSH
- Metabolic Networks and Pathways MeSH
- Molecular Structure MeSH
- Oxidative Stress MeSH
- Reactive Oxygen Species metabolism MeSH
- Plants drug effects metabolism MeSH
- Metals, Heavy adverse effects chemistry metabolism MeSH
- Environmental Exposure * adverse effects MeSH
- Publication type
- Journal Article MeSH
- Review MeSH
We have recently discovered that brassinosteroids (BRs) can inhibit the growth of etiolated pea seedlings dose-dependently in a similar manner to the 'triple response' induced by ethylene. We demonstrate here that the growth inhibition of etiolated pea shoots strongly correlates with increases in ethylene production, which also responds dose-dependently to applied BRs. We assessed the biological activities of two natural BRs on pea seedlings, which are excellent material as they grow rapidly, and respond both linearly and uni-phasically to applied BRs. We then compared the BRs' inhibitory effects on growth, and induction of ethylene and ACC (1-aminocyclopropane-1-carboxylic acid) production, to those of representatives of other phytohormone classes (cytokinins, auxins, and gibberellins). Auxin induced ca. 50-fold weaker responses in etiolated pea seedlings than brassinolide, and the other phytohormones induced much weaker (or opposite) responses. Following the optimization of conditions for determining ethylene production after BR treatment, we found a positive correlation between BR bioactivity and ethylene production. Finally, we optimized conditions for pea growth responses and developed a new, highly sensitive, and convenient bioassay for BR activity.
- MeSH
- Amino Acids, Cyclic metabolism MeSH
- Biological Assay methods MeSH
- Brassinosteroids pharmacology MeSH
- Ethylenes metabolism MeSH
- Pisum sativum drug effects growth & development metabolism MeSH
- Growth Inhibitors pharmacology MeSH
- Indoleacetic Acids pharmacology MeSH
- Plant Growth Regulators pharmacokinetics pharmacology MeSH
- Seedlings drug effects growth & development metabolism MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
The fine tuning of hormone (e.g., auxin and gibberellin) levels and hormone signaling is required for maintaining normal embryogenesis. Embryo polarity, for example, is ensured by the directional movement of auxin that is controlled by various types of auxin transporters. Here, we present pieces of evidence for the auxin-gibberellic acid (GA) hormonal crosstalk during embryo development and the regulatory role of the Arabidopsis thaliana Calcium-Dependent Protein Kinase-Related Kinase 5 (AtCRK5) in this regard. It is pointed out that the embryogenesis of the Atcrk5-1 mutant is delayed in comparison to the wild type. This delay is accompanied with a decrease in the levels of GA and auxin, as well as the abundance of the polar auxin transport (PAT) proteins PIN1, PIN4, and PIN7 in the mutant embryos. We have previously showed that AtCRK5 can regulate the PIN2 and PIN3 proteins either directly by phosphorylation or indirectly affecting the GA level during the root gravitropic and hypocotyl hook bending responses. In this manuscript, we provide evidence that the AtCRK5 protein kinase can in vitro phosphorylate the hydrophilic loops of additional PIN proteins that are important for embryogenesis. We propose that AtCRK5 can govern embryo development in Arabidopsis through the fine tuning of auxin-GA level and the accumulation of certain polar auxin transport proteins.
- MeSH
- Arabidopsis growth & development metabolism MeSH
- Enzyme-Linked Immunosorbent Assay MeSH
- Gibberellins analysis metabolism MeSH
- Germination * MeSH
- Indoleacetic Acids metabolism MeSH
- Membrane Transport Proteins genetics metabolism MeSH
- Protein Serine-Threonine Kinases metabolism MeSH
- Arabidopsis Proteins genetics metabolism MeSH
- Receptors, Cell Surface metabolism MeSH
- Gene Expression Regulation, Plant MeSH
- Seeds anatomy & histology growth & development metabolism MeSH
- Publication type
- Journal Article MeSH
The apical hook is a transiently formed structure that plays a protective role when the germinating seedling penetrates through the soil towards the surface. Crucial for proper bending is the local auxin maxima, which defines the concave (inner) side of the hook curvature. As no sign of asymmetric auxin distribution has been reported in embryonic hypocotyls prior to hook formation, the question of how auxin asymmetry is established in the early phases of seedling germination remains largely unanswered. Here, we analyzed the auxin distribution and expression of PIN auxin efflux carriers from early phases of germination, and show that bending of the root in response to gravity is the crucial initial cue that governs the hypocotyl bending required for apical hook formation. Importantly, polar auxin transport machinery is established gradually after germination starts as a result of tight root-hypocotyl interaction and a proper balance between abscisic acid and gibberellins.This article has an associated 'The people behind the papers' interview.
- MeSH
- Arabidopsis MeSH
- Plants, Genetically Modified MeSH
- Gibberellins metabolism MeSH
- Hypocotyl growth & development MeSH
- Germination physiology MeSH
- Plant Roots growth & development MeSH
- Abscisic Acid metabolism MeSH
- Indoleacetic Acids metabolism MeSH
- Meristem growth & development MeSH
- Gravity Sensing physiology MeSH
- Arabidopsis Proteins metabolism MeSH
- Gene Expression Regulation, Plant MeSH
- Plant Growth Regulators metabolism MeSH
- Seedlings growth & development MeSH
- Gene Expression Regulation, Developmental MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
