ABSTRACT
This study explores the impact of juglone on cucumber (Cucumis sativus cv. Beith Alpha), scrutinizing its effects on seed germination, growth, and the polyphenol oxidase (PPO) enzyme's activity and gene expression. Employing concentrations ranging from 0.01 to 0.5 mM, we found juglone's effects to be concentration-dependent. At lower concentrations (0.01 and 0.1 mM), juglone promoted root and shoot growth along with germination, whereas higher concentrations (0.25 and 0.5 mM) exerted inhibitory effects, delineating a threshold for its allelopathic influence. Notably, PPO activity surged, especially at 0.5 mM in roots, hinting at oxidative stress involvement. Real-time PCR unveiled that juglone modulates PPO gene expression in cotyledons, peaking at 0.1 mM and diminishing at elevated levels. Correlation analyses elucidated a positive link between juglone-induced root growth and cotyledon PPO gene expression but a negative correlation with heightened root enzyme activity. Additionally, germination percentage inversely correlated with root PPO activity, while PPO activities positively associated with dopa and catechol substrates in both roots and cotyledons. Molecular docking studies revealed juglone's selective interactions with PPO's B chain, suggesting regulatory impacts. Protein interaction assessments highlighted juglone's influence on amino acid metabolism, and molecular dynamics indicated juglone's stronger, more stable binding to PPO, inferring potential alterations in enzyme function and stability. Conclusively, our findings elucidate juglone's dose-dependent physiological and biochemical shifts in cucumber plants, offering insights into its role in plant growth, stress response, and metabolic modulation.
Subject(s)
Catechol Oxidase , Cucumis sativus , Germination , Molecular Docking Simulation , Naphthoquinones , Plant Roots , Catechol Oxidase/metabolism , Catechol Oxidase/genetics , Cucumis sativus/genetics , Cucumis sativus/enzymology , Cucumis sativus/drug effects , Naphthoquinones/pharmacology , Naphthoquinones/metabolism , Germination/drug effects , Plant Roots/drug effects , Plant Roots/growth & development , Plant Roots/genetics , Plant Roots/enzymology , Gene Expression Regulation, Plant/drug effects , Plant Proteins/metabolism , Plant Proteins/genetics , Cotyledon/genetics , Cotyledon/drug effects , Cotyledon/enzymologyABSTRACT
Brassinosteroids (BRs) are phytohormones that regulate stomatal development. In this study, we report that BR represses stomatal development in etiolated Arabidopsis (Arabidopsis thaliana) cotyledons via transcription factors BRASSINAZOLE RESISTANT 1 (BZR1) and bri1-EMS SUPPRESSOR1 (BES1), which directly target MITOGEN-ACTIVATED PROTEIN KINASE KINASE 9 (MKK9) and FAMA, 2 important genes for stomatal development. BZR1/BES1 bind MKK9 and FAMA promoters in vitro and in vivo, and mutation of the BZR1/BES1 binding motif in MKK9/FAMA promoters abolishes their transcription regulation by BZR1/BES1 in plants. Expression of a constitutively active MKK9 (MKK9DD) suppressed overproduction of stomata induced by BR deficiency, while expression of a constitutively inactive MKK9 (MKK9KR) induced high-density stomata in bzr1-1D. In addition, bzr-h, a sextuple mutant of the BZR1 family of proteins, produced overabundant stomata, and the dominant bzr1-1D and bes1-D mutants effectively suppressed the stomata-overproducing phenotype of brassinosteroid insensitive 1-116 (bri1-116) and brassinosteroid insensitive 2-1 (bin2-1). In conclusion, our results revealed important roles of BZR1/BES1 in stomatal development, and their transcriptional regulation of MKK9 and FAMA expression may contribute to BR-regulated stomatal development in etiolated Arabidopsis cotyledons.
Subject(s)
Arabidopsis Proteins , Arabidopsis , Brassinosteroids , Cotyledon , DNA-Binding Proteins , Gene Expression Regulation, Plant , Nuclear Proteins , Plant Stomata , Arabidopsis/genetics , Arabidopsis/growth & development , Arabidopsis/metabolism , Arabidopsis Proteins/metabolism , Arabidopsis Proteins/genetics , Brassinosteroids/metabolism , Plant Stomata/growth & development , Plant Stomata/genetics , Plant Stomata/drug effects , Cotyledon/genetics , Cotyledon/growth & development , Cotyledon/metabolism , Cotyledon/drug effects , Gene Expression Regulation, Plant/drug effects , DNA-Binding Proteins/metabolism , DNA-Binding Proteins/genetics , Nuclear Proteins/metabolism , Nuclear Proteins/genetics , Mutation/genetics , Promoter Regions, Genetic/genetics , Etiolation , Transcription Factors/metabolism , Transcription Factors/genetics , Protein Binding/drug effects , Mitogen-Activated Protein Kinase Kinases/metabolism , Mitogen-Activated Protein Kinase Kinases/geneticsABSTRACT
Somatic embryogenesis is an effective tool for the production of forest tree seedlings with desirable characteristics; however, the low initiation frequency and productivity of high-quality mature somatic embryos are still limiting factors for Larix kaempferi (Japanese larch). Here, we analyzed the expression pattern of L. kaempferi cyclin-dependent kinase B 1;2 (LaCDKB1;2) during somatic embryogenesis in L. kaempferi and its relationship with the cell proliferation rate. We also analyzed the effect of LaCDKB1;2 over-expression on somatic embryo quality. The results revealed a positive correlation between LaCDKB1;2 expression and the cell proliferation rate during the proliferation stage. After LaCDKB1;2 over-expression, the proliferation rate of cultures increased, and the number of somatic embryos in transgenic cultures was 2.69 times that in non-transformed cultures. Notably, the number of normal cotyledonary embryos in transgenic cultures was 3 times that in non-transformed cultures, indicating that LaCDKB1;2 not only increases the proliferation of cultures and the number of somatic embryos but also improves the quality of somatic embryos. These results provide insight into the regulatory mechanisms of somatic embryogenesis as well as new Larix breeding material.
Subject(s)
Cotyledon/growth & development , Larix/genetics , Plant Proteins/genetics , Plant Somatic Embryogenesis Techniques/methods , Abscisic Acid/pharmacology , Cell Proliferation , Cotyledon/drug effects , Cotyledon/genetics , Cyclin-Dependent Kinases/genetics , Gene Expression Regulation, Plant/drug effects , Larix/cytology , Phylogeny , Plant Breeding/methods , Plant Cells , Plant Proteins/metabolism , Plants, Genetically Modified , Promoter Regions, GeneticABSTRACT
In plants, the effective mobilization of seed nutrient reserves is crucial during germination and for seedling establishment. The Arabidopsis H+-PPase-loss-of-function fugu5 mutants exhibit a reduced number of cells in the cotyledons. This leads to enhanced post-mitotic cell expansion, also known as compensated cell enlargement (CCE). While decreased cell numbers have been ascribed to reduced gluconeogenesis from triacylglycerol, the molecular mechanisms underlying CCE remain ill-known. Given the role of indole 3-butyric acid (IBA) in cotyledon development, and because CCE in fugu5 is specifically and completely cancelled by ech2, which shows defective IBA-to-indoleacetic acid (IAA) conversion, IBA has emerged as a potential regulator of CCE. Here, to further illuminate the regulatory role of IBA in CCE, we used a series of high-order mutants that harbored a specific defect in IBA-to-IAA conversion, IBA efflux, IAA signaling, or vacuolar type H+-ATPase (V-ATPase) activity and analyzed the genetic interaction with fugu5-1. We found that while CCE in fugu5 was promoted by IBA, defects in IBA-to-IAA conversion, IAA response, or the V-ATPase activity alone cancelled CCE. Consistently, endogenous IAA in fugu5 reached a level 2.2-fold higher than the WT in 1-week-old seedlings. Finally, the above findings were validated in icl-2, mls-2, pck1-2 and ibr10 mutants, in which CCE was triggered by low sugar contents. This provides a scenario in which following seed germination, the low-sugar-state triggers IAA synthesis, leading to CCE through the activation of the V-ATPase. These findings illustrate how fine-tuning cell and organ size regulation depend on interplays between metabolism and IAA levels in plants.
Subject(s)
Arabidopsis/physiology , Indoleacetic Acids/metabolism , Indoles/pharmacology , Inorganic Pyrophosphatase/genetics , Vacuolar Proton-Translocating ATPases/genetics , Arabidopsis/drug effects , Arabidopsis/genetics , Arabidopsis Proteins/drug effects , Arabidopsis Proteins/genetics , Cell Enlargement/drug effects , Cotyledon/drug effects , Cotyledon/genetics , Cotyledon/physiology , Enoyl-CoA Hydratase/genetics , Germination , Loss of Function Mutation , Organ Size , Signal Transduction/drug effects , Sugars/metabolismABSTRACT
The fungal toxin fusicoccin (FC) induces rapid cell elongation, proton extrusion and plasma membrane hyperpolarization in maize coleoptile cells. Here, these three parameters were simultaneously measured using non-abraded and non-peeled segments with the incubation medium having access to their lumen. The dose-response curve for the FC-induced growth was sigmoidal shaped with the maximum at 10-6 M over 10 h. The amplitudes of the rapid growth and proton extrusion were significantly higher for FC than those for indole-3-acetic acid (IAA). The differences between the membrane potential changes that were observed in the presence of FC and IAA relate to the permanent membrane hyperpolarization for FC and transient hyperpolarization for IAA. It was also found that the lag times of the rapid growth, proton extrusion and membrane hyperpolarization were shorter for FC compared to IAA. At 30 °C, the biphasic kinetics of the IAA-induced growth rate could be changed into a monophasic (parabolic) one, which is characteristic for FC-induced rapid growth. It has been suggested that the rates of the initial phase of the FC- and IAA-induced growth involve two common mechanisms that consist of the proton pumps and potassium channels whose contribution to the action of both effectors on the rapid growth is different.
Subject(s)
Cotyledon/drug effects , Cotyledon/physiology , Glycosides/pharmacology , Membrane Potentials/drug effects , Plant Development/drug effects , Protons , Zea mays/drug effects , Zea mays/physiology , Hydrogen-Ion Concentration , Kinetics , Plant Growth Regulators/metabolism , TemperatureABSTRACT
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.
Subject(s)
Arabidopsis Proteins/genetics , Arabidopsis/growth & development , Etiolation/drug effects , Plant Growth Regulators/pharmacology , Arabidopsis/drug effects , Arabidopsis/genetics , Cotyledon/drug effects , Cotyledon/genetics , Cotyledon/growth & development , Gene Expression Regulation, Developmental/drug effects , Gene Expression Regulation, Plant/drug effects , Hypocotyl/drug effects , Hypocotyl/genetics , Hypocotyl/growth & development , TemperatureABSTRACT
After germination, plants determine their morphogenesis, such as hypocotyl elongation and cotyledon opening, by responding to various wavelengths of light (photomorphogenesis). Cryptochrome is a blue-light photoreceptor that controls de-etiolation, stomatal opening and closing, flowering time, and shade avoidance. Successful incorporation of these phenotypes as indicators into a chemical screening system results in faster selection of candidate compounds. Here, we describe phenotypic screening for the blue-light response of Arabidopsis thaliana seedling and the resulting process that clarifies that the compound obtained in the screening is an inhibitor of cryptochromes.
Subject(s)
Arabidopsis/metabolism , Cryptochromes/antagonists & inhibitors , Small Molecule Libraries/analysis , Arabidopsis/growth & development , Arabidopsis/radiation effects , Cell-Free System , Cotyledon/anatomy & histology , Cotyledon/drug effects , Cotyledon/radiation effects , Cryptochromes/metabolism , Cryptochromes/radiation effects , Culture Media , Hypocotyl/anatomy & histology , Hypocotyl/drug effects , Hypocotyl/radiation effects , Image Processing, Computer-Assisted , Light , Phenotype , Protein Biosynthesis/drug effects , Protein Biosynthesis/radiation effects , Recombinant Proteins/biosynthesis , Seedlings/drug effects , Seedlings/radiation effects , Small Molecule Libraries/pharmacologyABSTRACT
Histone acetylation plays an important role in plant growth and development. Here, we investigated the effect of sodium butyrate (NaB), a histone deacetylase inhibitor, on adventitious shoot formation from protoplast-derived calli and cotyledon explants of tobacco (Nicotiana benthamiana) and tomato (Solanum lycopersicum). The frequency of adventitious shoot formation from protoplast-derived calli was higher in shoot induction medium (SIM) containing NaB than in the control. However, the frequency of adventitious shoot formation from cotyledon explants of tobacco under the 0.1 mM NaB treatment was similar to that in the control, but it decreased with increasing NaB concentration. Unlike in tobacco, NaB decreased adventitious shoot formation in tomato explants in a concentration-dependent manner, but it did not have any effect on adventitious shoot formation in calli. NaB inhibited or delayed the expression of D-type cyclin (CYCD3-1) and shoot-regeneration regulatory gene WUSCHEL (WUS) in cotyledon explants of tobacco and tomato. However, compared to that in control SIM, the expression of WUS was promoted more rapidly in tobacco calli cultured in NaB-containing SIM, but the expression of CYCD3-1 was inhibited. In conclusion, the effect of NaB on adventitious shoot formation and expression of CYCD3-1 and WUS genes depended on the plant species and whether the effects were tested on explants or protoplast-derived calli.
Subject(s)
Butyric Acid/pharmacology , Nicotiana/drug effects , Nicotiana/growth & development , Solanum lycopersicum/drug effects , Solanum lycopersicum/growth & development , Cotyledon/drug effects , Cotyledon/genetics , Cotyledon/growth & development , Cyclin D/genetics , Gene Expression Regulation, Plant/drug effects , Genes, Plant/drug effects , Histone Deacetylase Inhibitors/pharmacology , Solanum lycopersicum/genetics , Plant Proteins/genetics , Plant Shoots/drug effects , Plant Shoots/genetics , Plant Shoots/growth & development , Species Specificity , Nicotiana/geneticsABSTRACT
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.
Subject(s)
Arabidopsis/genetics , Cotyledon/genetics , Gene Expression Regulation, Plant , Hypocotyl/genetics , Protein Serine-Threonine Kinases/genetics , Seedlings/genetics , Arabidopsis/drug effects , Arabidopsis/enzymology , Arabidopsis/growth & development , Arabidopsis Proteins/genetics , Arabidopsis Proteins/metabolism , Basic Helix-Loop-Helix Transcription Factors/genetics , Basic Helix-Loop-Helix Transcription Factors/metabolism , Cotyledon/drug effects , Cotyledon/enzymology , Cotyledon/growth & development , DNA, Bacterial/genetics , DNA, Bacterial/metabolism , DNA-Binding Proteins/genetics , DNA-Binding Proteins/metabolism , Gene Expression Profiling , Gene Expression Regulation, Developmental , Gibberellins/metabolism , Gibberellins/pharmacology , Hypocotyl/drug effects , Hypocotyl/enzymology , Hypocotyl/growth & development , Indoleacetic Acids/metabolism , Indoleacetic Acids/pharmacology , Mutagenesis, Insertional , Plant Growth Regulators/pharmacology , Plants, Genetically Modified , Protein Serine-Threonine Kinases/metabolism , Seedlings/drug effects , Seedlings/enzymology , Seedlings/growth & development , Transcription Factors/genetics , Transcription Factors/metabolism , TranscriptomeABSTRACT
Nicotinamide adenine dinucleotide (NAD) plays a central role in redox metabolism in all domains of life. Additional roles in regulating posttranslational protein modifications and cell signaling implicate NAD as a potential integrator of central metabolism and programs regulating stress responses and development. Here we found that NAD negatively impacts stomatal development in cotyledons of Arabidopsis thaliana. Plants with reduced capacity for NAD+ transport from the cytosol into the mitochondria or the peroxisomes exhibited reduced numbers of stomatal lineage cells and reduced stomatal density. Cotyledons of plants with reduced NAD+ breakdown capacity and NAD+ -treated cotyledons also presented reduced stomatal number. Expression of stomatal lineage-related genes was repressed in plants with reduced expression of NAD+ transporters as well as in plants treated with NAD+ . Impaired NAD+ transport was further associated with an induction of abscisic acid (ABA)-responsive genes. Inhibition of ABA synthesis rescued the stomatal phenotype in mutants deficient in intracellular NAD+ transport, whereas exogenous NAD+ feeding of aba-2 and ost1 seedlings, impaired in ABA synthesis and ABA signaling, respectively, did not impact stomatal number, placing NAD upstream of ABA. Additionally, in vivo measurement of ABA dynamics in seedlings of an ABA-specific optogenetic reporter - ABAleon2.1 - treated with NAD+ showed increases in ABA content suggesting that NAD+ impacts on stomatal development through ABA synthesis and signaling. Our results demonstrate that intracellular NAD+ homeostasis as set by synthesis, breakdown and transport is essential for normal stomatal development, and provide a link between central metabolism, hormone signaling and developmental plasticity.
Subject(s)
Abscisic Acid/metabolism , Arabidopsis/metabolism , NAD/metabolism , Plant Stomata/growth & development , Arabidopsis/drug effects , Arabidopsis/genetics , Arabidopsis/growth & development , Arabidopsis Proteins/genetics , Arabidopsis Proteins/metabolism , Cotyledon/drug effects , Cotyledon/metabolism , Gene Expression Regulation, Plant , Mitochondria/metabolism , Mutation , NAD/pharmacology , Plant Stomata/metabolismABSTRACT
In this works, a simple, efficient and repeatable protocol was developed for in vitro regeneration via callus-mediated organogenesis of Neolamarkia Cadamba using cotyledonary petioles and hypocotyls. Effects of basal medium, plant growth regulators, the types and age of explant on the formation of adventitious buds/shoots were studied. Meanwhile, histological analysis for early ontogenic stages and genetic stability assessment by flow cytometry were investigated. Our investigation demonstrated that, compared with 6-benzyladenine (BA), N6-(2-isopentenyl) adenine (2-ip), Thidiazuron (TDZ) was the optimal cytokinin for buds/shoots induction on cotyledon and hypocotyl explants. Douglas-fir and sugar pine medium (DCR) supplemented with 22.7 µM TDZ and 0.27 µM α-naphthalene acetic acid (NAA) was most effective on bud induction, with the highest bud-induction rate and numbers of buds on cotyledon and hypocotyl explants. The available shoot per explant hit 35.2 when the induced callus sub-cultured to a medium without TDZ. It was found that TDZ could promote induction of the callus and the buds, however, continuous exposure beyond 4 weeks of supplemented high concentration (exceed 11.35 µM), TDZ was harmful to the proliferation and growth of buds/shoots. DCR appeared more efficiency than Murashige and Skoog medium (MS), Woody Plant medium (WPM), anther culture of cereal crops medium (N6) on bud induction. Age of cotyledon and hypocotyl explants in 20-day to 25-day was most beneficial to adventitious buds/shoots formation. Histological investigation confirmed that the buds originated from the wounded incisions of cotyledonary petiole and hypocotyl fragments, with callus formation. The regeneration plantlets were successfully acclimatized in greenhouse, yielded above 95% survival rate in field, exhibited normal morphology and growth characteristics. The analysis of flow cytometry on N. cadamba indicated no variation in the ploidy levels between the regenerated plantlets and the donor trees. The developed procedure can be used for mass production, germplasm exchange and transgenic studies to improve the resistance of the species via Agrobacterium-mediated.
Subject(s)
Cell Culture Techniques/methods , Cinchona/growth & development , Cotyledon/cytology , Culture Media/chemistry , Hypocotyl/cytology , Benzyl Compounds/pharmacology , Cinchona/cytology , Cinchona/genetics , Cotyledon/drug effects , Cotyledon/genetics , Cytokinins/pharmacology , Flow Cytometry , Hypocotyl/drug effects , Hypocotyl/genetics , Naphthaleneacetic Acids/chemistry , Organogenesis, Plant , Phenylurea Compounds/pharmacology , Plant Growth Regulators/pharmacology , Ploidies , Purines/pharmacology , Thiadiazoles/pharmacology , Tropical ClimateABSTRACT
Hormesis, which describes the stimulatory effect of low doses of toxic substances on growth, is a well-known phenomenon in the plant and animal kingdoms. However, the mechanisms that are involved in this phenomenon are still poorly understood. We performed preliminary studies on corn coleoptile sections, which showed a positive correlation between the stimulation of growth by Cd or Pb and an increase in the auxin and H2O2 content in the coleoptile sections. Subsequently, we grew corn seedlings in hydroponic culture and tested a wide range of Cd or Pb concentrations in order to determine hormetic growth stimulation. In these seedlings the gas exchange and the chlorophyll a fluorescence, as well as the content of chlorophyll, flavonol, auxin and hydrogen peroxide, were measured. We found that during the hormetic stimulation of growth, the response of the photosynthetic apparatus to Cd and Pb differed significantly. While the application of Cd mostly caused a decrease in various photosynthetic parameters, the application of Pb stimulated some of them. Nevertheless, we discovered that the common features of the hormetic stimulation of shoot growth by heavy metals are an increase in the auxin and flavonol content and the maintenance of hydrogen peroxide at the same level as the control plants.
Subject(s)
Cadmium/pharmacology , Hormesis/drug effects , Indoleacetic Acids/pharmacology , Lead/pharmacology , Oxidative Stress/physiology , Photosynthesis/drug effects , Zea mays/drug effects , Chlorophyll/metabolism , Cotyledon/drug effects , Cotyledon/physiology , Hormesis/physiology , Hydrogen Peroxide/pharmacology , Hydroponics/methods , Oxidants/pharmacology , Photosynthesis/physiology , Plant Growth Regulators/pharmacology , Plant Roots/drug effects , Plant Roots/physiology , Seedlings/drug effects , Seedlings/physiology , Zea mays/physiologyABSTRACT
Adventitious roots form only at the proximal cut surface (PCS) but not at the distal cut surface (DCS) of mango cotyledon segments. In this study, mango embryos treated with indole-3-butyric acid (IBA) showed significantly increased adventitious root formation, while those treated with 2, 3, 5-triiodobenzoic acid (TIBA) demonstrated complete inhibition of adventitious rooting. Mango embryos treated with auxin influx inhibitors demonstrated lower inhibition of adventitious roots than those treated with TIBA. The endogenous indol-3-acetic acid (IAA) content on the PCS and DCS was similar at 0 h, then increased on both surfaces after 6 h, and IAA content on the PCS were always higher than those on the DCS. We cloned three genes encoding auxin efflux carriers (i.e., MiPIN2-4) and examined their temporal and spatial expression patterns under different treatments. Relative expression of all MiPINs studied was very low at 0 h but significantly increased on both PCS and DCS from 1 d to 10 d, to varying degrees. We overexpressed MiPIN1-4 in Arabidopsis plants and found a significant increase in adventitious root quantity in MiPIN1 and MiPIN3 transgenic lines. Immunofluorescence results showed that MiPIN1 and MiPIN3 are primarily localized in the vascular tissues and the cells adjacent to abaxial surface. In conclusion, we propose that in mango cotyledon segments, wounding stimulates IAA biosynthesis, the transcription levels of PIN genes were significantly increased in different magnitudes on the PCS and DCS, resulting in polar IAA transport from the DCS to PCS via the vascular tissues, thereby triggering adventitious root formation.
Subject(s)
Cotyledon , Indoleacetic Acids , Mangifera , Membrane Transport Proteins , Plant Roots , Arabidopsis/genetics , Cotyledon/drug effects , Cotyledon/growth & development , Indoleacetic Acids/pharmacology , Mangifera/growth & development , Mangifera/metabolism , Membrane Transport Proteins/genetics , Membrane Transport Proteins/metabolism , Plant Growth Regulators/pharmacology , Plant Proteins/genetics , Plant Proteins/metabolism , Plant Roots/drug effects , Plants, Genetically Modified/drug effects , Plants, Genetically Modified/genetics , Triiodobenzoic Acids/pharmacologyABSTRACT
Cultivating rice in wet or water direct seeding systems is simple and time and labor efficient. Rice (Oryza sativa) seeds are a unique cereal that can germinate not only when submerged, but also in anoxic conditions. Many complicated hormone signals interact in submerged seed germination. Ethylene is involved in rice coleoptile elongation, but little is known regarding the role of auxin signaling under submergence. This study demonstrated that the coleoptile is shorter and curlier when submerged with 2,3,5-triiodobenzoic acid (TIBA). In transcriptomic analysis, 3448 of the 31,860 genes were upregulated, and 4360 genes were downregulated with submergence and TIBA treatment. The Gene Ontology function classification results demonstrated that upregulated differentially expressed genes (DEGs) were mainly involved in redox, stress, and signal transduction, whereas the down-regulated DEGs were mainly involved in RNA transcription, stress, and development. Furthermore, auxin signaling involved in the carbohydrate metabolism pathway was demonstrated while using transcriptomic analysis and confirmed in a quantitative real-time polymerase chain reaction. In addition, the transcript levels of development-related genes and mitochondria-electron- transport-related genes were regulated by auxin signaling under submergence. Auxin signaling was not only involved in regulating rice coleoptile elongation and development, but also regulated secondary metabolism, carbohydrate metabolism, and mitochondria electron transport under submergence. Our results presented that auxin signaling plays an important role during rice coleoptile elongation upon the submergence condition and improving the advance of research of direct rice seeding system.
Subject(s)
Gene Expression Profiling/methods , Indoleacetic Acids/metabolism , Oryza/genetics , Carbohydrate Metabolism/genetics , Cotyledon/drug effects , Cotyledon/growth & development , Cotyledon/metabolism , Down-Regulation/drug effects , Electron Transport/genetics , Mitochondria/genetics , Mitochondria/metabolism , Oryza/growth & development , Oryza/metabolism , Plant Proteins/genetics , Plant Proteins/metabolism , Signal Transduction/drug effects , Triiodobenzoic Acids/pharmacology , Up-Regulation/drug effectsABSTRACT
BACKGROUND: Efficient organogenesis induction in eggplant (Solanum melongena L.) is required for multiple in vitro culture applications. In this work, we aimed at developing a universal protocol for efficient in vitro regeneration of eggplant mainly based on the use of zeatin riboside (ZR). We evaluated the effect of seven combinations of ZR with indoleacetic acid (IAA) for organogenic regeneration in five genetically diverse S. melongena and one S. insanum L. accessions using two photoperiod conditions. In addition, the effect of six different concentrations of indolebutyric acid (IBA) in order to promote rooting was assessed to facilitate subsequent acclimatization of plants. The ploidy level of regenerated plants was studied. RESULTS: In a first experiment with accessions MEL1 and MEL3, significant (p < 0.05) differences were observed for the four factors evaluated for organogenesis from cotyledon, hypocotyl and leaf explants, with the best results obtained (9 and 11 shoots for MEL1 and MEL3, respectively) using cotyledon tissue, 16 h light / 8 h dark photoperiod conditions, and medium E6 (2 mg/L of ZR and 0 mg/L of IAA). The best combination of conditions was tested in the other four accessions and confirmed its high regeneration efficiency per explant when using both cotyledon and hypocotyl tissues. The best rooting media was R2 (1 mg/L IBA). The analysis of ploidy level revealed that between 25 and 50% of the regenerated plantlets were tetraploid. CONCLUSIONS: An efficient protocol for organogenesis of both cultivated and wild accessions of eggplant, based on the use of ZR, is proposed. The universal protocol developed may be useful for fostering in vitro culture applications in eggplant requiring regeneration of plants and, in addition, allows developing tetraploid plants without the need of antimitotic chemicals.
Subject(s)
Isopentenyladenosine/analogs & derivatives , Organogenesis, Plant/physiology , Solanum melongena/growth & development , Cotyledon/drug effects , Cotyledon/growth & development , Hypocotyl/drug effects , Hypocotyl/growth & development , In Vitro Techniques , Indoleacetic Acids/pharmacology , Isopentenyladenosine/pharmacology , Organogenesis, Plant/drug effects , Plant Growth Regulators/pharmacology , Plant Leaves/drug effects , Plant Leaves/growth & development , Plant Shoots/drug effects , Plant Shoots/growth & development , Ploidies , Regeneration/drug effects , Solanum melongena/metabolismABSTRACT
Seedling establishment consists of the former stage (i.e. skotomorphogenesis) and the latter stage (i.e. photomorphogenesis). Due to specific developmental processes in plants, the two stages may have different sensitivities to antibiotics. Tetracycline (TC), for example, is a major-use antibiotic. Radicle length, the relatively sensitive endpoint in plant skotomorphogenesis, is less sensitive than all of the indices of cotyledon colour and pigments in plant photomorphogenesis to TC stress. In conclusion, we suggest that plant photomorphogenesis may be more sensitive than plant skotomorphogenesis to stresses of antibiotics, but which needs further studies.
Subject(s)
Anti-Bacterial Agents/toxicity , Brassica rapa/drug effects , Plant Development/drug effects , Seedlings/drug effects , Soil Pollutants/toxicity , Tetracycline/toxicity , Arabidopsis Proteins/genetics , Brassica rapa/growth & development , Brassica rapa/radiation effects , Cotyledon/drug effects , Cotyledon/growth & development , Gene Expression Regulation, Plant , Light , Pigments, Biological/biosynthesis , Seedlings/growth & development , Seedlings/radiation effectsABSTRACT
KEY MESSAGE: Several members of WOX and KNOX gene families and several plant growth regulators, basically cytokinins and auxins, play a key role during adventitious caulogenesis in the conifer Pinus pinea. Similar to Arabidopsis thaliana, Pinus pinea shoot organogenesis is a multistep process. However, there are key differences between both species, which may alter the underlying physiological and genetic programs. It is unknown if the genic expression models during angiosperm development may be applicable to conifers. In this work, an analysis of the endogenous content of different plant growth regulators and the expression of genes putatively involved in adventitious caulogenesis in P. pinea cotyledons was conducted. A multivariate analysis of both datasets was also realized through partial least squares regression and principal component analysis to obtain an integral vision of the mechanisms involved in caulogenesis in P. pinea. Analyses show that cotyledons cultured in the presence of benzyladenine during long times (2-6 days) cluster separately from the rest of the samples, suggesting that the benzyladenine increase observed during the first hours of culture is sufficient to trigger the caulogenic response through the activation of specific developmental programs. In particular, the most relevant factors involved in this process are the cytokinins trans-zeatin, dihydrozeatin, trans-zeatin riboside and isopentenyl adenosine; the auxin indoleacetic acid; and the genes PpWUS, PpWOX5, PpKN2, PpKN3 and PipiRR1. WUS is functional in pines and has an important role in caulogenesis. Interestingly, WOX5 also seems to participate in the process, although its specific role has not been determined.
Subject(s)
Cotyledon/chemistry , Cotyledon/metabolism , Meristem/metabolism , Pinus/metabolism , Plant Growth Regulators/metabolism , Plant Proteins/metabolism , Aminobutyrates/pharmacology , Cells, Cultured , Chromatography, High Pressure Liquid , Cotyledon/drug effects , Cotyledon/genetics , Cytokinins/metabolism , Gene Expression Regulation, Plant/drug effects , Gene Expression Regulation, Plant/genetics , Homeodomain Proteins/genetics , Homeodomain Proteins/metabolism , Indoleacetic Acids/metabolism , Meristem/chemistry , Meristem/genetics , Pinus/chemistry , Pinus/genetics , Plant Proteins/genetics , Plant Shoots/metabolism , Seeds/drug effects , Seeds/growth & development , Seeds/metabolism , Tandem Mass SpectrometryABSTRACT
Free polyamine (PA) titers in plants may be regulated through reversible conjugate formation and/or through modulation of their synthesis, transport and degradation. PA signaling involves the well-acknowledged signaling molecule, nitric oxide (NO), which functions in diverse biological processes. Present investigations demonstrate the influence of salt stress (120 mM NaCl) and exogenous NO donor (250 µM Diethylenetriamine, DETA) on PA homeostasis of 2 d old, etiolated sunflower (Helianthus annuus L.) seedling cotyledons as a long-distance signaling response. Significantly enhanced intracellular spermine (Spm) accumulation was observed in seedling cotyledons under salt stress and in response to NO donor, the increase being more pronounced in seedlings treated with NO, evidently as a result of upregulation of the PA biosynthetic enzymes - arginine decarboxylase (ADC) and S-adenosylmethionine decarboxylase (SAMDC) - as revealed by Western blot and confocal imaging (CLSM). Moreover, salt stress induced the activity of polyamine oxidase (PAO), a PA catabolic enzyme, while NO lowered its activity in salt-stressed seedling cotyledons. NO, thus, appears to assist the seedlings in adapting to salt stress by positively regulating PA homeostasis through regulation of PA distribution between free, conjugated and bound forms, increased accumulation of PA biosynthetic enzymes and lowering the rate of PA catabolism.
Subject(s)
Cotyledon/metabolism , Helianthus/metabolism , Nitric Oxide/metabolism , Polyamines/metabolism , Seedlings/metabolism , Adenosylmethionine Decarboxylase/metabolism , Carboxy-Lyases/metabolism , Cotyledon/drug effects , Helianthus/drug effects , Salt Stress , Seedlings/drug effects , Sodium Chloride/pharmacologyABSTRACT
Seedling establishment is a critical step in environment colonisation by higher plants that frequently occurs under adverse conditions. Thus, we carried out an integrated analysis of seedling growth, water status, ion accumulation, reserve mobilisation, metabolite partitioning and hydrolase activity during seedling establishment of the native Caatinga species Piptadenia moniliformis (Benth.) Luckow & R.W. Jobson under salinity. Two-day-old seedlings were cultivated in vitro for 4 days in water agar (control) or supplemented with 50 or 100 mm NaCl. Biochemical determinations were performed according to standard spectrophotometric protocols. We found that 100 mm NaCl stimulated starch degradation, amylase activity and soluble sugar accumulation, but limited storage protein hydrolysis in the cotyledons of P. moniliformis seedlings. Although Na+ accumulation in the seedling affected K+ partitioning between different organs, it was not possible to associate the salt-induced changes in reserve mobilisation with Na+ toxicity, or water status, in the cotyledons. Remarkably, we found that starch content increased in the roots of P. moniliformis seedlings under 100 mm NaCl, probably in response to the toxic effects of Na+ . The mobilisation of carbon and nitrogen reserves is independently regulated in P. moniliformis seedlings under salt stress. The salt-induced delay in seedling establishment and the resulting changes in the source-sink relationship may lead to storage protein retention in the cotyledons. Possibly, the intensification of starch mobilisation in the cotyledons supported starch accumulation in the root as a potential mechanism to mitigate Na+ toxicity.
Subject(s)
Carbon/metabolism , Moniliformis/metabolism , Nitrogen/metabolism , Seedlings/metabolism , Animals , Cotyledon/drug effects , Cotyledon/metabolism , Moniliformis/drug effects , Salinity , Seedlings/drug effects , Sodium/metabolism , Sodium Chloride/pharmacologyABSTRACT
Naphthoquinones, plants secondary metabolites are known for their antibacterial, antifungal, anti-inflammatory, anti-cancer and anti-parasitic properties. The biological activity of naphthoquinones is connected with their ability to generate reactive oxygen species and to modify biological molecules at their nucleophilic sites. In our research, the effect of naphthazarin (DHNQ) combined with 2-hydroxy-1,4-naphthoquinone (NQ-2-OH) or 1,4-naphthoquinone (1,4-NQ) on the elongation growth, pH changes of the incubation medium, oxidative stress and redox activity of maize coleoptile cells were investigated. This paper describes experiments performed with maize (Zea mays L.) coleoptile segments, which is a classical model system to study plant cell elongation growth. The data presented clearly demonstrate that lawsone and 1,4-naphthoquinone combined with naphthazarin, at low concentrations (1 and 10 nM), reduced the endogenous and IAA-induced (Indole-3-Acetic Acid) elongation growth of maize coleoptile segments. Those changes in growth correlated with the proton concentration in the incubation medium, which suggests that the changes in the growth of maize coleoptile segments observed in the presence of naphthoquinones are mediated through the activity of PM Hâº-ATPase. The presence of naphthoquinones induced oxidative stress in the maize coleoptile tissue by producing hydrogen peroxide and causing changes in the redox activity. Moreover, the incubation of maize segments with both naphthoquinones combined with naphthazarin resulted in lipid peroxidation and membrane damage. The regulation of PM Hâº-ATPase activity, especially its inhibition, may result from two major types of reaction: first, a direct interaction between an enzyme and naphthoquinone, which leads to the covalent modification of the protein thiols and the generation of thioethers, which have been found to alter the activity of the PM Hâº-ATPases; second, naphthoquinones induce reactive oxygen species (ROS) production, which inhibits PM Hâº-ATPases by increasing cytosolic Ca2+. This harmful effect was stronger when naphthazarin and 1,4-naphthoquinone were added together. Taking these results into account, it can be suggested that by combining naphthoquinones in small quantities, an alternative to synthetic pesticides could be developed.