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Sample records for abscisic acid-mediated callose

  1. An Arabidopsis callose synthase

    Ostergaard, Lars; Petersen, Morten; Mattsson, Ole;

    2002-01-01

    unclear whether callose synthases can also produce cellulose and whether plant cellulose synthases may also produce beta-1,3-glucans. We describe here an Arabidopsis gene, AtGsl5, encoding a plasma membrane-localized protein homologous to yeast beta-1,3-glucan synthase whose expression partially......Beta-1,3-glucan polymers are major structural components of fungal cell walls, while cellulosic beta-1,4-glucan is the predominant polysaccharide in plant cell walls. Plant beta-1,3-glucan, called callose, is produced in pollen and in response to pathogen attack and wounding, but it has been...

  2. Arabidopsis CALCIUM-DEPENDENT PROTEIN KINASE8 and CATALASE3 Function in Abscisic Acid-Mediated Signaling and H2O2 Homeostasis in Stomatal Guard Cells under Drought Stress.

    Zou, Jun-Jie; Li, Xi-Dong; Ratnasekera, Disna; Wang, Cun; Liu, Wen-Xin; Song, Lian-Fen; Zhang, Wen-Zheng; Wu, Wei-Hua

    2015-05-01

    Drought is a major threat to plant growth and crop productivity. Calcium-dependent protein kinases (CDPKs, CPKs) are believed to play important roles in plant responses to drought stress. Here, we report that Arabidopsis thaliana CPK8 functions in abscisic acid (ABA)- and Ca(2+)-mediated plant responses to drought stress. The cpk8 mutant was more sensitive to drought stress than wild-type plants, while the transgenic plants overexpressing CPK8 showed enhanced tolerance to drought stress compared with wild-type plants. ABA-, H2O2-, and Ca(2+)-induced stomatal closing were impaired in cpk8 mutants. Arabidopsis CATALASE3 (CAT3) was identified as a CPK8-interacting protein, confirmed by yeast two-hybrid, coimmunoprecipitation, and bimolecular fluorescence complementation assays. CPK8 can phosphorylate CAT3 at Ser-261 and regulate its activity. Both cpk8 and cat3 plants showed lower catalase activity and higher accumulation of H2O2 compared with wild-type plants. The cat3 mutant displayed a similar drought stress-sensitive phenotype as cpk8 mutant. Moreover, ABA and Ca(2+) inhibition of inward K(+) currents were diminished in guard cells of cpk8 and cat3 mutants. Together, these results demonstrated that CPK8 functions in ABA-mediated stomatal regulation in responses to drought stress through regulation of CAT3 activity. PMID:25966761

  3. Isolated complete corpus callosal agenesis

    Jaiganesh S, Venkateshwaran A, Naresh Kumar C, Rajasekhar KV

    2014-11-01

    Full Text Available Isolated complete corpus callosal agenesis is a rare entity. Usually this condition will be an associated finding in other syndromes. 3 month old male child came with complaints of deformed foot on both sides, not having a social smile and neck holding. Patient referred to the Radiology department for MRI brain which showed complete absence of corpus callosum, widely separated and parallely placed lateral ventricles, colpocephaly, high riding of 3rd ventricle and absence of cingulate gyrus and radial arrangement of gyri along the interhemispheric fissure. Hence it was reported as isolated complete corpus callosal agenesis and this article describes the Embryogenesis, anatomy, developmental anomalies and its clinical manifestations & prognosis.

  4. Callosal alterations in pyridoxine-dependent epilepsy

    Friedman, S.D.; Ishak, G.E.; Poliachik, S.L.; Poliakov, A.V.; Otto, R.K.; Shaw, D.W.; Willemsen, M.A.A.P.; Bok, L.A.; Gospe, S.M., Jr.

    2014-01-01

    AIM: While there have been isolated reports of callosal morphology differences in pyridoxine-dependent epilepsy (PDE), a rare autosomal disorder caused by ALDH7A1 gene mutations, no study has systematically evaluated callosal features in a large sample of patients. This study sought to overcome this

  5. Conflict of intentions due to callosal disconnection

    Nishikawa, T.; Okuda, J; MIZUTA, I; Ohno, K.; Jamshidi, J; Tokunaga, H.; Ikejiri, Y; Nakagawa, Y.; Yoshimine, T.; Tanabe, H; Takeda, M.

    2001-01-01

    OBJECTIVES—Three patients with callosal syndrome manifested a peculiar symptom in that they were unable to perform intended whole body actions because another intention emerged in competition with the original one. Attempts were made to clarify the symptomatology of this manifestation and its possible mechanism is discussed.
METHODS—The three patients are described and previous reports on patients with callosal damage were reviewed. Four additional patients with similar s...

  6. Callosal Disconnection Syndrome Associated with Relapsing Polychondritis.

    Baba, Toru; Kanno, Shigenori; Shijo, Tomomi; Nishio, Yoshiyuki; Iizuka, Osamu; Kamimura, Naoto; Ishii, Tomonori; Mori, Etsuro

    2016-01-01

    Relapsing polychondritis (RP) is a rare inflammatory disorder of the cartilagenous structures, and it sometimes involves the central nervous system. Encephalitis associated with RP causes a wide variety of symptoms according to the affected sites. We herein report the first case of 72-year-old right-handed man who developed acute meningoencephalitis associated with RP involving the corpus callous. After immunosuppressive therapy, his symptoms dramatically improved, but difficulty in performing bimanual movements with occasional diagonistic dyspraxia in his right hand remained. Because callosal signs are easily missed, especially in acute settings, it would be useful to know that RP can sometimes cause callosal disconnection syndrome. PMID:27150878

  7. Dynamics of callose deposition and B-1,3-glucanase expression during reproductive events in sexual and apomictic Hieracium

    Tucker, M.R.; Paech, N.A.; Willemse, M.T.M.; Koltunow, A.M.G.

    2001-01-01

    Callose accumulates in the walls of cells undergoing megasporogenesis during embryo sac formation in angiosperm ovules. Deficiencies in callose deposition have been observed in apomictic plants and causal linkages between altered callose deposition and apomictic initiation proposed. In apomictic Hie

  8. Selective serotonergic excitation of callosal projection neurons

    Daniel eAvesar

    2012-03-01

    Full Text Available Serotonin (5-HT acting as a neurotransmitter in the cerebral cortex is critical for cognitive function, yet how 5-HT regulates information processing in cortical circuits is not well understood. We tested the serotonergic responsiveness of layer 5 pyramidal neurons (L5PNs of the mouse medial prefrontal cortex (mPFC, and found 3 distinct response types: long-lasting 5-HT1A (1A receptor-dependent inhibitory responses (84% of L5PNs, 5-HT2A (2A receptor-dependent excitatory responses (9%, and biphasic responses in which 2A-dependent excitation followed brief inhibition (5%. Relative to 5-HT-inhibited neurons, those excited by 5-HT had physiological properties characteristic of callosal/commissural (COM neurons that project to the contralateral cortex. We tested whether serotonergic responses in cortical pyramidal neurons are correlated with their axonal projection pattern using retrograde fluorescent labeling of COM and corticopontine-projecting (CPn neurons. 5-HT generated excitatory or biphasic responses in all 5-HT-responsive layer 5 COM neurons. Conversely, CPn neurons were universally inhibited by 5-HT. Serotonergic excitation of COM neurons was blocked by the 2A antagonist MDL 11939, while serotonergic inhibition of CPn neurons was blocked by the 1A antagonist WAY 100635, confirming a role for these two receptor subtypes in regulating pyramidal neuron activity. Selective serotonergic excitation of COM neurons was not layer-specific, as COM neurons in layer 2/3 were also selectively excited by 5-HT relative to their non-labeled pyramidal neuron neighbors. Because neocortical 2A receptors are implicated in the etiology and pathophysiology of schizophrenia, we propose that COM neurons may represent a novel cellular target for intervention in psychiatric disease.

  9. Abscisic Acid Signaling in Plants

    Vaňková, Radomíra

    NEW YORK : Springer, 2012 - (Ahmad, P.; Prasad, M.), s. 359-368 ISBN 978-1-4614-0633-4 R&D Projects: GA ČR GA522/09/2058 Institutional research plan: CEZ:AV0Z50380511 Keywords : PP2C * PYR/PYL/RCAR proteins * Abscisic acid Subject RIV: ED - Physiology

  10. Electrophysiological Correlates of Morphological Neuroplasticity in Human Callosal Dysgenesis

    Lazarev, Vladimir V.; de Carvalho Monteiro, Myriam; Vianna-Barbosa, Rodrigo; deAzevedo, Leonardo C.; Lent, Roberto; Tovar-Moll, Fernanda

    2016-01-01

    In search for the functional counterpart of the alternative Probst and sigmoid bundles, considered as morphological evidence of neuroplasticity in callosal dysgenesis, electroencephalographic (EEG) coherence analysis was combined with high resolution and diffusion tensor magnetic resonance imaging. Data of two patients with callosal agenesis, plus two with typical partial dysgenesis with a remnant genu, and one atypical patient with a substantially reduced genu were compared to those of fifteen neurotypic controls. The interhemispheric EEG coherence between homologous nontemporal brain regions corresponded to absence or partial presence of callosal connections. A generalized coherence reduction was observed in complete acallosal patients, as well as coherence preservation in the anterior areas of the two patients with a remnant genu. jThe sigmoid bundles found in three patients with partial dysgenesis correlated with augmented EEG coherence between anterior regions of one hemisphere and posterior regions of the other. These heterologous (crossed) interhemispheric connections were asymmetric in both imaging and EEG patterns, with predominance of the right-anterior-to-left-posterior connections over the mirror ones. The Probst bundles correlated with higher intrahemispheric long-distance coherence in all patients. The significant correlations observed for the delta, theta and alpha bands indicate that these alternative pathways are functional, although the neuropsychological nature of this function is still unknown. PMID:27055255

  11. Comparative Studies on Callose Formation in Powdery Mildew Compatible and Incompatible Barley

    Skou, Jens-Peder; Jørgensen, Jørgen Helms; Lilholt, Ulla

    1984-01-01

    Callose formation in barley mutants, lines and varieties with different genes for resistance to powdery mildew in seven different loci was compared. Only barley with resistance genes in the ml-o locus showed so early a callose formation passing off at such a high rate that it prevented fungal pen...

  12. Diffusion Weighted Callosal Integrity Reflects Interhemispheric Communication Efficiency in Multiple Sclerosis

    Warlop, Nele P.; Achten, Eric; Debruyne, Jan; Vingerhoets, Guy

    2008-01-01

    We aimed to investigate the relation between damage in the corpus callosum and the performance on an interhemispheric communication task in patients with multiple sclerosis (MS). Relative callosal lesion load defined as the ratio between callosal area and the total lesion load in the total corpus callosum, and the diffusion tensor imaging (DTI)…

  13. Callosal lesions and behavior: history and modern concepts.

    Devinsky, Orrin; Laff, Rachel

    2003-12-01

    Callosotomy has played a unique role in the treatment of epilepsy and in the understanding of human brain function. The pioneering work of Dejerine and Liepmann presenting the first findings of callosal lesion pathology at the turn of the 20th century was accepted but then quickly forgotten. Two schools resurrected the phoenix of callosal syndromes: Roger Sperry and Michael Gazzaniga leading in experimental neuroscience, and Norman Geschwind leading in clinical neurology. Callosotomy remains an effective technique to treat atonic, tonic, and tonic-clonic seizures, especially in patients with symptomatic generalized epilepsies such as Lennox-Gastaut syndrome. Neurologic, cognitive, and behavioral complications limit its use given that precise characterization of these complications as well as their frequency is difficult. The high frequencies of developmental delays, severe seizures, head injuries, antiepileptic drug burden, and other factors limit the ability to attribute a specific change to surgical intervention, since surgery can change multiple factors. For example, subtle behavioral changes in executive function and personality are difficult to delineate in a population with preexisting neurologic and psychiatric disorders. Despite this, a clearer picture of the effects of callosotomy, as defined by clinical neurology and neuropsychology as well as cognitive neuroscience, is emerging. PMID:14698693

  14. Motor callosal disconnection in early relapsing-remitting multiple sclerosis.

    Wahl, Mathias; Hübers, Annemarie; Lauterbach-Soon, Birgit; Hattingen, Elke; Jung, Patrick; Cohen, Leonardo G; Ziemann, Ulf

    2011-06-01

    In relapsing-remitting multiple sclerosis (RRMS) the corpus callosum (CC) is often and early affected by macroscopic lesions when investigated by conventional MRI. We sought to determine to which extent microstructural and effective disconnection of the CC are already present in RRMS patients at the earliest stages of the disease prior to evidence of macroscopic CC lesion. We compared 16 very early RRMS patients (median expanded disability status scale (EDSS), 1.5; range, 0-2.0) to an age-matched group of healthy controls and focused analysis to the motor CC, i.e. that part of the CC relaying interhemispheric motor information. A combined functional magnetic resonance imaging/diffusion tensor imaging fiber-tracking procedure was applied to identify the callosal motor fibers (CMFs) connecting the hand areas of the primary motor cortices of the two hemispheres. Fractional anisotropy (FA) within the motor CC (FA-CC) assessed the CMF microstructural integrity. Bifocal paired transcranial magnetic stimulation (TMS) tested short-interval interhemispheric inhibition (S-IHI), an established measure of CMF effective connectivity. FA-CC and S-IHI were significantly reduced in early RRMS compared to healthy controls. Furthermore, a significant linear correlation between microstructure (FA-CC) and function (S-IHI) in the controls was broken down in the patients. These abnormalities were obtained in the absence of macroscopic CMF lesion in conventional MRI, and whilst motor hand/arm function in the nine-hole-peg test and corticospinal conduction time were normal. Findings suggest that reductions in FA and S-IHI may serve as surrogate markers of motor callosal disconnection at the earliest stages of RRMS prior to development of macroscopic lesion. PMID:21495114

  15. Why Size Matters: Differences in Brain Volume Account for Apparent Sex Differences in Callosal Anatomy

    Luders, Eileen; Toga, Arthur W.; Thompson, Paul M.

    2013-01-01

    Numerous studies have demonstrated a sexual dimorphism of the human corpus callosum. However, the question remains if sex differences in brain size, which typically is larger in men than in women, or biological sex per se account for the apparent sex differences in callosal morphology. Comparing callosal dimensions between men and women matched for overall brain size may clarify the true contribution of biological sex, as any observed group difference should indicate pure sex effects. We thus...

  16. Callose deposition during gravitropism of Zea mays and Pisum sativum and its inhibition by 2-deoxy-D-glucose

    Jaffe, M. J.; Leopold, A. C.

    1984-01-01

    In etiolated corn (Zea mays L.) and etiolated pea (Pisum sativum L.) seedlings, a gravitropic stimulation induces the deposition of callose. In the corn coleoptiles this occurs within 5 min of gravity stimulation, and prior to the beginning of curvature. Both gravitropic curvature and callose deposition reach their maxima by 12 h. Within the first 2 h more callose is deposited on the upper (concave) side, but after 2-3 h, this deposition pattern is reversed. An inhibitor of protein glycosylation, 2-deoxy-D-glucose (DDG), inhibits callose production and considerably retards gravitropic bending in both species of plants. Mannose can relieve the inhibition of gravitropic bending by DDG. The pea mutant "Ageotropum", which does not respond to gravity when etiolated, also fails to produce callose in response to a gravitic stimulus. These correlations indicate that callose deposition may be a biochemical component of gravitropism in plant shoots.

  17. Tannic acid-mediated green synthesis of antibacterial silver nanoparticles.

    Kim, Tae Yoon; Cha, Song-Hyun; Cho, Seonho; Park, Youmie

    2016-04-01

    The search for novel antibacterial agents is necessary to combat microbial resistance to current antibiotics. Silver nanoparticles (AgNPs) have been reported to be effective antibacterial agents. Tannic acid is a polyphenol compound from plants with antioxidant and antibacterial activities. In this report, AgNPs were prepared from silver ions by tannic acid-mediated green synthesis (TA-AgNPs). The reaction process was facile and involved mixing both silver ions and tannic acid. The absorbance at 423 nm in the UV-Visible spectra demonstrated that tannic acid underwent a reduction reaction to produce TA-AgNPs from silver ions. The synthetic yield of TA-AgNPs was 90.5 % based on inductively coupled plasma mass spectrometry analysis. High-resolution transmission electron microscopy and atomic force microscopy images indicated that spherical-shaped TA-AgNPs with a mean particle size of 27.7-46.7 nm were obtained. Powder high-resolution X-ray diffraction analysis indicated that the TA-AgNP structure was face-centered cubic with a zeta potential of -27.56 mV. The hydroxyl functional groups of tannic acid contributed to the synthesis of TA-AgNPs, which was confirmed by Fourier transform infrared spectroscopy. The in vitro antibacterial activity was measured using the minimum inhibitory concentration (MIC) method. The TA-AgNPs were more effective against Gram-negative bacteria than Gram-positive bacteria. The MIC for the TA-AgNPs in all of the tested strains was in a silver concentration range of 6.74-13.48 μg/mL. The tannic acid-mediated synthesis of AgNPs afforded biocompatible nanocomposites for antibacterial applications. PMID:26895244

  18. Persistent activation of microglia is associated with neuronal dysfunction of callosal projecting pathways and multiple sclerosis-like lesions in relapsing--remitting experimental autoimmune encephalomyelitis

    Rasmussen, Stine; Wang, Yue; Kivisäkk, Pia;

    2007-01-01

    Cortical pathology, callosal atrophy and axonal loss are substrates of progression in multiple sclerosis (MS). Here we describe cortical, periventricular subcortical lesions and callosal demyelination in relapsing-remitting experimental autoimmune encephalomyelitis in SJL mice that are similar to...

  19. The enhanced callose deposition in barley with ml-o powdery mildew resistance genes

    Skou, Jens-Peder

    1985-01-01

    Carborundum treatment of barley leaves induced a callose deposition which was detected as diffuse blotches in the epidermal cells of susceptible barleys and as deeply stained tracks along the scratches in barleys with the ml-o powdery mildew resistance gene. Subsequent inoculation with powdery...... mildew resulted in appositions that enlarged inversely to their size in the respective varieties when inoculated without carborundum treatment. Aphids sucking the leaves resulted in rows of callose containing spots along the anticlinal cell walls. The spots were larger in the ml-o mutant than...... in the mother variety. Callose was deposited in connection with the pleiotropic necrotic spotting in barleys with the ml-o gene. Modification of the necrotic spotting by crossing the ml-o gene into other gene backgrounds did not result in any change in the size of appositions upon inoculation with powdery...

  20. Role of callose synthases in transfer cell wall development in tocopherol deficient Arabidopsis mutants

    Hiroshi eMaeda

    2014-02-01

    Full Text Available Tocopherols (vitamin E are lipid-soluble antioxidants produced by all plants and algae, and many cyanobacteria, yet their functions in these photosynthetic organisms are still not fully understood. We have previously reported that the vitamin E deficient 2 (vte2 mutant of Arabidopsis thaliana is sensitive to low temperature (LT due to impaired transfer cell wall (TCW development and photoassimilate export, associated with massive callose deposition in transfer cells of the phloem. To further understand the role of tocopherols in LT induced TCW development we compared global transcript profiles of vte2 and wild type leaves during LT treatment. Tocopherol deficiency had no impact on global gene expression in permissive conditions, but affected expression of 77 genes after 48 hours of LT treatment. In vte2 relative to wild type, genes related with solute transport were repressed, while those involved in various pathogen responses and cell wall modifications, such as GLUCAN SYNTHASE LIKE genes (GSL4 and GSL11, were induced. However, introduction of gsl4 or gsl11 mutations into the vte2 background did not suppress callose deposition or the overall LT-induced phenotypes of vte2. Intriguingly, introduction of a mutation of GSL5, the major GSL responsible for pathogen-induced callose deposition, into vte2 substantially reduced vascular callose deposition at LT, but again had no effect on the photoassimilate export phenotype of LT-treated vte2. These results suggest that GSL5 plays a major role in TCW callose deposition in LT-treated vte2 but that this GSL5-dependent callose deposition is not the primary cause of the impaired photoassimilate export phenotype.

  1. Distribution of callose synthase, cellulose synthase, and sucrose synthase in tobacco pollen tube is controlled in dissimilar ways by actin filaments and microtubules

    Cai, G.; Faleri, C.; Casino, C.; Emons, A.M.C.; Cresti, M.

    2011-01-01

    Callose and cellulose are fundamental components of the cell wall of pollen tubes and are probably synthesized by distinct enzymes, callose synthase and cellulose synthase, respectively. We examined the distribution of callose synthase and cellulose synthase in tobacco (Nicotiana tabacum) pollen tub

  2. Cetalox and analogues: synthesis via acid-mediated polyene cyclizations.

    Snowden, Roger L

    2008-06-01

    Using a novel, acid-mediated cyclization methodology, a direct access to Cetalox ((+/-)-1; a commercially important ambergris-type odorant) and various structurally related didehydro (i.e., 19, 26, and 30) and tetradehydro (i.e., 28 and 37/38) analogues is described. Treatment of either (E,E)-14 or (E)-15 with an excess of FSO(3)H in 2-nitropropane at -90 degrees stereospecifically afforded (+/-)-1 in 40 and 42% yield, respectively. Under similar conditions, cyclization of (E)-18 or 20 furnished 19 in 60 and 64% yield, respectively. Analogously, using an excess of ClSO(3)H in CH(2)Cl(2) at -80 degrees, 26 is formed with high stereoselectivity by cyclization of either (E)-24 or (Z)-25 (52 and 31% yield, resp.); in the same manner, 28 was prepared from 27 (22% yield). The same principle was applied to the synthesis of racemic Superambrox (30), via cyclization of 35, but only with poor selectivity (22%) and low yield (7%). Another approach via cyclization of (E)-40 under solvolysis conditions (excess TFA in CH(2)Cl(2) at -10 degrees) gave a higher yield (15%) with improved selectivity (43%). Finally, cyclization of 34 (1:1 diastereoisomer mixture) afforded 37/38 (10:1) in 27% yield. The qualitative organoleptic properties of 19, 26, 28, 30, and 37/38 (10:1) are briefly discussed. PMID:18618391

  3. Ex vitro transfer and abscisic acid

    Pospíšilová, Jana; Synková, Helena; Haisel, Daniel; Vágner, Martin; Baťková, Petra

    Faro, 2007. s. 33-33. [International Symposium on Acclimatization and Establishment of Micropropagated Plants /3./. 12.09.2007-15.09.2007, University of Algarve] R&D Projects: GA ČR GA522/07/0227 Institutional research plan: CEZ:AV0Z50380511 Source of funding: V - iné verejné zdroje Keywords : abscisic acid * antioxidants * ex vitro transfer * in vitro growth * stomata * photoinhibition * xanthophyll cycl Subject RIV: ED - Physiology

  4. Iron-dependent callose deposition adjusts root meristem maintenance to phosphate availability.

    Müller, Jens; Toev, Theresa; Heisters, Marcus; Teller, Janine; Moore, Katie L; Hause, Gerd; Dinesh, Dhurvas Chandrasekaran; Bürstenbinder, Katharina; Abel, Steffen

    2015-04-20

    Plant root development is informed by numerous edaphic cues. Phosphate (Pi) availability impacts the root system architecture by adjusting meristem activity. However, the sensory mechanisms monitoring external Pi status are elusive. Two functionally interacting Arabidopsis genes, LPR1 (ferroxidase) and PDR2 (P5-type ATPase), are key players in root Pi sensing, which is modified by iron (Fe) availability. We show that the LPR1-PDR2 module facilitates, upon Pi limitation, cell-specific apoplastic Fe and callose deposition in the meristem and elongation zone of primary roots. Expression of cell-wall-targeted LPR1 determines the sites of Fe accumulation as well as callose production, which interferes with symplastic communication in the stem cell niche, as demonstrated by impaired SHORT-ROOT movement. Antagonistic interactions of Pi and Fe availability control primary root growth via meristem-specific callose formation, likely triggered by LPR1-dependent redox signaling. Our results link callose-regulated cell-to-cell signaling in root meristems to the perception of an abiotic cue. PMID:25898169

  5. The enhanced callose deposition in barley with ml-o powdery mildew resistance genes

    Skou, Jens-Peder

    1985-01-01

    Carborundum treatment of barley leaves induced a callose deposition which was detected as diffuse blotches in the epidermal cells of susceptible barleys and as deeply stained tracks along the scratches in barleys with the ml-o powdery mildew resistance gene. Subsequent inoculation with powdery...

  6. Altered callose deposition during embryo sac formation of multi-pistil mutant (mp1) in Medicago sativa.

    Zhou, H C; Jin, L; Li, J; Wang, X J

    2016-01-01

    Whether callose deposition is the cause or result of ovule sterility in Medicago sativa remains controversial, because it is unclear when and where changes in callose deposition and dissolution occur during fertile and sterile embryo sac formation. Here, alfalfa spontaneous multi-pistil mutant (mp1) and wild-type plants were used to compare the dynamics of callose deposition during embryo sac formation using microscopy. The results showed that both mutant and wild-type plants experienced megasporogenesis and megagametogenesis, and there was no significant difference during megasporogenesis. In contrast to the wild-type plants, in which the mature embryo sac was observed after three continuous cycles of mitosis, functional megaspores of mutant plants developed abnormally after the second round of mitosis, leading to degeneration of synergid, central, and antipodal cells. Callose deposition in both mutant and wild-type plants was first observed in the walls of megasporocytes, and then in the megaspore tetrad walls. After meiosis, the callose wall began to degrade as the functional megaspore underwent mitosis, and almost no callose was observed in the mature embryo sac in wild-type plants. However, callose deposition was observed in mp1 plants around the synergid, and increased with the development of the embryo sac, and was mainly deposited at the micropylar end. Our results indicate that synergid, central, and antipodal cells, which are surrounded by callose, may degrade owing to lack of nutrition. Callose accumulation around the synergid and at the micropylar end may hinder signals required for the pollen tube to enter the embryo sac, leading to abortion. PMID:27323128

  7. Presence of abscisic acid, a phytohormone, in the mammalian brain

    This paper reports the presence of abscisic acid, one of the most important phytohormones, in the central nervous system of pigs and rats. The identification of this hormone in brain was made after extensive purification by using a radioimmunoassay that is very specific for (+)-cis-abscisic acid. The final product of purification from mammalian brain has the same properties as authentic abscisic acid: it crossreacts in the radioimmunoassay for the phytohormone and it has the same retention properties and the same gas chromatography/mass spectrometry characteristics. Moreover, like (+)-cis-abscisic acid itself, the brain factor inhibits stomatal apertures of abaxial epidermis strips of Setcreasea purpurea Boom (Commelinaceae). The presence of abscisic acid conjugates that are present in plants has also been identified in brain

  8. Presence of abscisic acid, a phytohormone, in the mammalian brain

    Le Page-Degivry, M.T.; Bidard, J.N.; Rouvier, E.; Bulard, C.; Lazdunski, M.

    1986-02-01

    This paper reports the presence of abscisic acid, one of the most important phytohormones, in the central nervous system of pigs and rats. The identification of this hormone in brain was made after extensive purification by using a radioimmunoassay that is very specific for (+)-cis-abscisic acid. The final product of purification from mammalian brain has the same properties as authentic abscisic acid: it crossreacts in the radioimmunoassay for the phytohormone and it has the same retention properties and the same gas chromatography/mass spectrometry characteristics. Moreover, like (+)-cis-abscisic acid itself, the brain factor inhibits stomatal apertures of abaxial epidermis strips of Setcreasea purpurea Boom (Commelinaceae). The presence of abscisic acid conjugates that are present in plants has also been identified in brain.

  9. Perinatal testosterone exposure and cerebral lateralisation in adult males: evidence for the callosal hypothesis.

    Hollier, Lauren P; Maybery, Murray T; Keelan, Jeffrey A; Hickey, Martha; Whitehouse, Andrew J O

    2014-12-01

    Two competing theories address the influence of foetal testosterone on cerebral laterality: one proposing exposure to high foetal testosterone concentrations is related to atypical lateralisation (Geschwind-Galaburda hypothesis), the other that high foetal testosterone concentrations exaggerate typical lateralisation (callosal hypothesis). The current study examined the relationship between cord testosterone concentrations and cerebral laterality for language and spatial memory in adulthood. Male participants with high (>0.15nmol) and low (lateralisation of language was more common in the high-testosterone group than in the low-testosterone group, χ(2)=4.50, df=1, p=034. Spatial memory laterality was unrelated to cord testosterone level. Our findings indicate that foetal testosterone exposure is related to language laterality in a direction that supports the callosal hypothesis. PMID:25148786

  10. Relation of callosal structure to cognitive abilities in temporal lobe epilepsy

    Christine eSchneider

    2014-02-01

    Full Text Available The main objective of this paper is to analyse the influence of mesial temporal lobe epilepsy (TLE on the morphology of the corpus callosum (CC and its relation to cognitive abilities. More specifically, we investigated correlations between intellectual abilities and callosal morphology, while additionally exploring the modulating impact of (a side of seizure onset (b age of disease onset.For this reason a large representative sample of patients with hippocampal sclerosis (n=79; 35 males; 44 females; age: 18-63 years with disease onset ranging from 0 to 50 years of age, and consisting of 46 left and 33 right TLE patients was recruited. Intelligence was measured using the Wechsler Adult Intelligence Scale Revised (WAIS-R.To get localizations of correlations with high anatomic precision, callosal morphology was examined using computational mesh-based modeling methods, applied to anatomical brain MRI scans.Intellectual performance was positively associated with callosal thickness in anterior and midcallosal callosal regions, with anterior parts being slightly more affected by age of disease onset and side of seizure onset than posterior parts. Earlier age at onset of epilepsy was associated with lower thickness in anterior and midcallosal regions. In addition, laterality of seizure onset had a significant influence on anterior CC morphology, with left hemispheric origin having stronger effects.We found that in TLE, anterior and midcallosal CC morphology are related to cognitive performance. The findings support recent findings of detrimental effects of early onset mTLE on anterior brain regions and of a distinct effect particularly of left TLE on frontal lobe functioning and structure. The causal nature of the relationship remains an open question, i.e., whether CC morphology impacts IQ development or whether IQ development impacts CC morphology, or both.

  11. Roles of Abscisic Acid in Fruit Ripening

    Sutthiwal SETHA

    2012-12-01

    Full Text Available Abscisic acid (ABA is a plant growth regulator, and it plays a variety of important roles throughout a plant’s life cycle. These roles include seed development and dormancy, plant response to environmental stresses, and fruit ripening. ABA concentration is very low in unripe fruit, but it increases as a fruit ripens, so it is therefore believed that ABA plays an important role in regulating the rate of fruit ripening. This article reviews the effect of ABA on ripening and quality of climacteric and non-climacteric fruits. The effects of ABA application on fruit ripening are subsequently discussed. Moreover, it is found that during fruit ripening, ABA also contributes to other functions, such as ethylene and respiratory metabolism, pigment and color changes, phenolic metabolism and nutritional contents, cell wall metabolism and fruit softening, and sugar and acid metabolism. These processes are all discussed as part of the relationship between ABA and fruit ripening, and the possibilities for its commercial application and use are highlighted.

  12. GENETIC ANALYSIS OF ABSCISIC ACID BIOSYNTHESIS

    MCCARTY D R

    2012-01-10

    The carotenoid cleavage dioxygenases (CCD) catalyze synthesis of a variety of apo-carotenoid secondary metabolites in plants, animals and bacteria. In plants, the reaction catalyzed by the 11, 12, 9-cis-epoxy carotenoid dioxygenase (NCED) is the first committed and key regulated step in synthesis of the plant hormone, abscisic acid (ABA). ABA is a key regulator of plant stress responses and has critical functions in normal root and seed development. The molecular mechanisms responsible for developmental control of ABA synthesis in plant tissues are poorly understood. Five of the nine CCD genes present in the Arabidopsis genome encode NCED's involved in control of ABA synthesis in the plant. This project is focused on functional analysis of these five AtNCED genes as a key to understanding developmental regulation of ABA synthesis and dissecting the role of ABA in plant development. For this purpose, the project developed a comprehensive set of gene knockouts in the AtNCED genes that facilitate genetic dissection of ABA synthesis. These mutants were used in combination with key molecular tools to address the following specific objectives: (1) the role of ABA synthesis in root development; (2) developmental control of ABA synthesis in seeds; (3) analysis of ATNCED over-expressers; (4) preliminary crystallography of the maize VP14 protein.

  13. Developmental evolution of flowering plant pollen tube cell walls: callose synthase (CalS gene expression patterns

    Abercrombie Jason M

    2011-07-01

    Full Text Available Abstract Background A number of innovations underlie the origin of rapid reproductive cycles in angiosperms. A critical early step involved the modification of an ancestrally short and slow-growing pollen tube for faster and longer distance transport of sperm to egg. Associated with this shift are the predominantly callose (1,3-β-glucan walls and septae (callose plugs of angiosperm pollen tubes. Callose synthesis is mediated by callose synthase (CalS. Of 12 CalS gene family members in Arabidopsis, only one (CalS5 has been directly linked to pollen tube callose. CalS5 orthologues are present in several monocot and eudicot genomes, but little is known about the evolutionary origin of CalS5 or what its ancestral function may have been. Results We investigated expression of CalS in pollen and pollen tubes of selected non-flowering seed plants (gymnosperms and angiosperms within lineages that diverged below the monocot/eudicot node. First, we determined the nearly full length coding sequence of a CalS5 orthologue from Cabomba caroliniana (CcCalS5 (Nymphaeales. Semi-quantitative RT-PCR demonstrated low CcCalS5 expression within several vegetative tissues, but strong expression in mature pollen. CalS transcripts were detected in pollen tubes of several species within Nymphaeales and Austrobaileyales, and comparative analyses with a phylogenetically diverse group of sequenced genomes indicated homology to CalS5. We also report in silico evidence of a putative CalS5 orthologue from Amborella. Among gymnosperms, CalS5 transcripts were recovered from germinating pollen of Gnetum and Ginkgo, but a novel CalS paralog was instead amplified from germinating pollen of Pinus taeda. Conclusion The finding that CalS5 is the predominant callose synthase in pollen tubes of both early-diverging and model system angiosperms is an indicator of the homology of their novel callosic pollen tube walls and callose plugs. The data suggest that CalS5 had transient expression

  14. Plasmodesmata without callose and calreticulin in higher plants - open channels for fast symplastic transport?

    Kirill N. Demchenko

    2014-03-01

    Full Text Available Plasmodesmata (PD represent membrane-lined channels that link adjacent plant cells across the cell wall. PD of higher plants contain a central tube of endoplasmic reticulum called desmotubule. Membrane and lumen proteins seem to be able to move through the desmotubule, but most transport processes through PD occur through the cytoplasmic annulus (Brunkard et al., 2013. Calreticulin (CRT, a highly conserved Ca2+-binding protein found in all multi-cellular eukaryotes, predominantly located in the ER, was shown to localize to PD, though not all PD accumulate CRT. In nitrogen fixing actinorhizal root nodules of the Australian tree Casuarina glauca, the primary walls of infected cells containing the microsymbiont become lignified upon infection. TEM analysis of these nodules showed that during the differentiation of infected cells, PD connecting infected cells, and connecting infected and adjacent uninfected cells, were reduced in number as well as diameter (Schubert et al., 2013. In contrast with PD connecting young infected cells, and most PD connecting mature infected and adjacent uninfected cells, PD connecting mature infected cells did not accumulate CRT. Furthermore, as shown here, these PD were not associated with callose, and based on their diameter, they probably had lost their desmotubules. We speculate that either this is a slow path to PD degradation, or that the loss of callose accumulation and presumably also desmotubules leads to the PD becoming open channels and improves metabolite exchange between cells.

  15. Callose Synthase Family Genes Involved in the Grapevine Defense Response to Downy Mildew Disease.

    Yu, Ying; Jiao, Li; Fu, Shufang; Yin, Ling; Zhang, Yali; Lu, Jiang

    2016-01-01

    The deposition of callose is a common plant defense response to intruding pathogens and part of the plant's innate immunity. In this study, eight grapevine callose synthase (CalS) genes were identified and characterized. To investigate biological function of CalS in grapevine against the infection of Plasmopara viticola, expression patterns of grapevine CalS family genes were analyzed among resistant/susceptible cultivars. After P. viticola infection, expression of CalS1, 3, 7, 8, 9, 10, and 11 were significantly modified among the grapevine cultivars. For example, the expression of CalS1 and CalS10 were greatly increased in downy mildew (DM)-immune Muscadinia rotundifolia 'Carlos' and 'Noble'. Transient expression assay with promoters of the CalS1 and CalS10 genes confirmed that they were regulated by the oomycete pathogen P. viticola. CalS1 promoter activity was also significantly up-regulated by ABA in DM-immune M. rotundifolia 'Noble', but down-regulated in DM-susceptible Vitis vinifera 'Chardonnay'. The CalS1 promoter, however, was also down-regulated by GA in 'Chardonnay', but not affected in 'Noble'. The promoter activity of CalS10 was significantly up-regulated by GA in 'Chardonnay', but not regulated by ABA at all. It is proposed that CalS1 and CalS10 were involved in grapevine defense against DM disease. PMID:26474330

  16. Characterization and partial purification of beta-1,3-D-glucan (callose) synthase from barley (Hordeum vulgare) leaves

    Pedersen, L.H.; Jacobsen, S.; Hejgaard, J.;

    1993-01-01

    was inhibited by UDP and uridine 5' triphosphate (UTP). Glucanase digestion of the in vitro product showed that it was a beta-1,3-linked polysaccharide. Two different procedures were used for further enrichment of polypeptides involved in callose synthase activity. Sucrose gradient centrifugation with...

  17. A new sign of callosal disconnection syndrome: agonistic dyspraxia. A case study.

    Lavados, Manuel; Carrasco, Ximena; Peña, Marcela; Zaidel, Eran; Zaidel, Dahlia; Aboitiz, Francisco

    2002-01-01

    We report a patient with callosal haemorrhage and no extracallosal involvement who developed a unique form of intermanual conflict. In the acute phase the patient showed a mild speech disturbance and right hemiparesis, and in her right hand, a grasp reflex and compulsive manipulation of tools, all attributable to transient frontal involvement. In the chronic phase there was intermanual conflict occasionally associated with the sensation of a second left hand. The patient also presented a sign consisting of compulsive, automatic execution of orders by one hand (the left or the right) when the patient was specifically asked to perform the movement with the other hand (the right or the left, respectively). There was no left-right confusion in this patient. We call this condition agonistic dyspraxia. In contrast with diagonistic dyspraxia, this consists of the agonistic behaviour of the other hand under conditions in which the hand that has been instructed to respond cannot execute the request. PMID:12529456

  18. Incorporation of oxygen into abscisic acid and phaseic acid for molecular oxygen

    Abscisic acid accumulates in detached, wilted leaves of Xanthium strumariu. When these leaves are subsequently rehydrated, phaseic acid, a catabolite of abscisic acid, accumulates. Analysis by gas chromatography-mass spectrometry of phaseic acid isolated from stressed and subsequently rehydrated leaves placed in an atmosphere containing 20% 18O2 and 80% N2 indicates that one atom of 18O is incorporated in the 6'-hydroxymethyl group of phaseic acid. This suggests that the enzyme that converts abscisic acid to phaseic acid is an oxygenase. Analysis by gas chromatography-mass spectrometry of abscisic acid isolated from stressed leaves kept in an atmosphere containing 18O2 indicates that one atom of 18O is presented in the carboxyl group of abscisic acid. Thus, when abscisic acid accumulates in water-streesed leaves, only one of the four oxygens present in the abscisic acid molecule is derived from molecular oxygen. This suggest that either (a) the oxygen present in the 1'-, 4'-, and one of the two oxygens at the 1-position of abscisic acid arise from water, or (b) there exists a stored precursor with oxygen atoms already present in the 1'- and 4'-positions of abscisic acid which is converted to abscisic acid under conditions of water stress. 17 references, 2 figures, 1 tables

  19. Reactive amyloidosis associated with ischial callosititis: a report with histology of ischial callosities in rhesus macaques (Macaca mulatta)

    Liu, David X.; Gilbert, Margaret H; Wang, Xiaolei; Didier, Peter J.; Veazey, Ronald S.

    2012-01-01

    Ischial callosities have received little attention in veterinary medicine even though they are distinguishing anatomic organs. The organs are characterized by a pair of hairless pads of thickened epidermis, located bilaterally in the gluteal region, which overlay the tuberosities of the ischia of all Old World monkeys, gibbons, and siamangs. The current report describes a case of reactive amyloidosis associated with ischial callosititis in a rhesus macaque (Macaca mulatta). Amyloid A (AA) pro...

  20. Deafferentation-Induced Plasticity of Visual Callosal Connections: Predicting Critical Periods and Analyzing Cortical Abnormalities Using Diffusion Tensor Imaging

    Jaime F. Olavarria

    2012-01-01

    Full Text Available Callosal connections form elaborate patterns that bear close association with striate and extrastriate visual areas. Although it is known that retinal input is required for normal callosal development, there is little information regarding the period during which the retina is critically needed and whether this period correlates with the same developmental stage across species. Here we review the timing of this critical period, identified in rodents and ferrets by the effects that timed enucleations have on mature callosal connections, and compare it to other developmental milestones in these species. Subsequently, we compare these events to diffusion tensor imaging (DTI measurements of water diffusion anisotropy within developing cerebral cortex. We observed that the relationship between the timing of the critical period and the DTI-characterized developmental trajectory is strikingly similar in rodents and ferrets, which opens the possibility of using cortical DTI trajectories for predicting the critical period in species, such as humans, in which this period likely occurs prenatally. Last, we discuss the potential of utilizing DTI to distinguish normal from abnormal cerebral cortical development, both within the context of aberrant connectivity induced by early retinal deafferentation, and more generally as a potential tool for detecting abnormalities associated with neurodevelopmental disorders.

  1. Age Differences in Interhemispheric Interactions: Callosal Structure, Physiological Function, and Behavior

    Brett W Fling

    2011-03-01

    Full Text Available There is a fundamental gap in understanding how brain structural and functional network connectivity are interrelated, how they change with age, and how such changes contribute to older adults’ sensorimotor deficits. Recent neuroimaging approaches including resting state functional connectivity MRI (fcMRI and diffusion tensor imaging (DTI have been used to assess brain functional (fcMRI and structural (DTI network connectivity, allowing for more integrative assessments of distributed neural systems than in the past. Declines in corpus callosum size and microstructure with advancing age have been well documented, but their contributions to age deficits in unimanual and bimanual function are not well defined. Our recent work implicates age-related declines in callosal size and integrity as a key contributor to unimanual and bimanual control deficits. Moreover, our data provide evidence for a fundamental shift in the balance of excitatory and inhibitory interhemispheric processes that occurs with age, resulting in age differences in the relationship between functional and structural network connectivity. Training studies suggest that the balance of interhemispheric interactions can be shifted with experience, making this a viable target for future interventions.

  2. Distinct roles of neuropilin 1 signaling for radial and tangential extension of callosal axons.

    Hatanaka, Yumiko; Matsumoto, Tomoko; Yanagawa, Yuchio; Fujisawa, Hajime; Murakami, Fujio; Masu, Masayuki

    2009-05-20

    Cortical excitatory neurons migrate from their origin in the ventricular zone (VZ) toward the pial surface. During migration, these neurons exhibit a stellate shape in the intermediate zone (IZ), transform into bipolar cells, and then initiate radial migration, extending a trailing process, which may lead to an axon. Here we examined the role of neuropilin 1 (NRP1) in these developmental events. Both NRP1 mRNA and protein were highly expressed in the IZ, where stellate-shaped cells were located. DiI labeling experiments showed that neuronal migration occurred normally in Nrp1 mutant mice up to embryonic day (E) 14.5, the latest day to which the mutant survives, with only subtle axonal defasciculation. However, interference with Nrp1 signaling at a later stage caused pathfinding errors: when a dominant negative form of Nrp1 was electroporated into the cortical VZ cells at E12.5 or E15.5 and examined perinatally, guidance errors were found in tangential axonal extension toward the midline. In contrast, no significant effect was noted on the migration of cortical excitatory neurons. These findings indicate that NRP1 plays an important role in the guidance of callosal axons originating from cortical excitatory neurons but does not support a role in their migration. Moreover, insofar as radial axonal extension within the cortical plate was unaffected, the present findings imply that molecular mechanisms for the axonal extension of excitatory neurons within the cortical plate are distinct from those in the white matter. PMID:19296474

  3. Poly(methacrylic acid)-mediated morphosynthesis of PbWO4 micro-crystals

    PbWO4 crystals with various morphologies were fabricated via a facile poly(methacrylic acid)-mediated hydrothermal route. Novel microsized PbWO4 single crystals with a needle-like shape as well as other morphologies, such as a fishbone, dendrite, sphere, spindle, ellipsoid, rod, and dumbbell with two dandelion-like heads, could be produced. The presence of PMAA, [Pb2+]/[WO42-] molar ratio (R), and aging temperature played key roles in the formation of the PbWO4 needle-like structures. Between temperatures of 60 to 150 C, the length and photoluminescence intensities of the PbWO4 micro needles significantly increased with aging temperature, while the diameter did not change remarkably. Time-dependent experiments revealed that the formation of PbWO4 microneedles involved an unusual growth process, involving nucleation, oriented assembly and controlled mesoscale restructuring of nanoparticle building blocks. (orig.)

  4. Small RNA Derived from the Virulence Modulating Region of the Potato spindle tuber viroid Silences callose synthase Genes of Tomato Plants.

    Adkar-Purushothama, Charith Raj; Brosseau, Chantal; Giguère, Tamara; Sano, Teruo; Moffett, Peter; Perreault, Jean-Pierre

    2015-08-01

    The tomato (Solanum lycopersicum) callose synthase genes CalS11-like and CalS12-like encode proteins that are essential for the formation of callose, a major component of pollen mother cell walls; these enzymes also function in callose formation during pathogen infection. This article describes the targeting of these callose synthase mRNAs by a small RNA derived from the virulence modulating region of two Potato spindle tuber viroid variants. More specifically, viroid infection of tomato plants resulted in the suppression of the target mRNAs up to 1.5-fold, depending on the viroid variant used and the gene targeted. The targeting of these mRNAs by RNA silencing was validated by artificial microRNA experiments in a transient expression system and by RNA ligase-mediated rapid amplification of cDNA ends. Viroid mutants incapable of targeting callose synthase mRNAs failed to induce typical infection phenotypes, whereas a chimeric viroid obtained by swapping the virulence modulating regions of a mild and a severe variant of Potato spindle tuber viroid greatly affected the accumulation of viroids and the severity of disease symptoms. These data provide evidence of the silencing of multiple genes by a single small RNA derived from a viroid. PMID:26290537

  5. Small RNA Derived from the Virulence Modulating Region of the Potato spindle tuber viroid Silences callose synthase Genes of Tomato Plants[OPEN

    Adkar-Purushothama, Charith Raj; Brosseau, Chantal; Giguère, Tamara; Sano, Teruo; Moffett, Peter; Perreault, Jean-Pierre

    2015-01-01

    The tomato (Solanum lycopersicum) callose synthase genes CalS11-like and CalS12-like encode proteins that are essential for the formation of callose, a major component of pollen mother cell walls; these enzymes also function in callose formation during pathogen infection. This article describes the targeting of these callose synthase mRNAs by a small RNA derived from the virulence modulating region of two Potato spindle tuber viroid variants. More specifically, viroid infection of tomato plants resulted in the suppression of the target mRNAs up to 1.5-fold, depending on the viroid variant used and the gene targeted. The targeting of these mRNAs by RNA silencing was validated by artificial microRNA experiments in a transient expression system and by RNA ligase-mediated rapid amplification of cDNA ends. Viroid mutants incapable of targeting callose synthase mRNAs failed to induce typical infection phenotypes, whereas a chimeric viroid obtained by swapping the virulence modulating regions of a mild and a severe variant of Potato spindle tuber viroid greatly affected the accumulation of viroids and the severity of disease symptoms. These data provide evidence of the silencing of multiple genes by a single small RNA derived from a viroid. PMID:26290537

  6. Action of Abscisic Acid on Auxin Transport and its Relation to Phototropism

    Naqvi, S. M.; Engvild, Kjeld Christensen

    1974-01-01

    The action of abscisic acid on the kinetics of auxin transport through Zea mays L. (cv. Goudster) coleoptiles has been investigated. Abscisic acid applied simultaneously with indoleacetic acid-2-14C in the donor block reduced the transport intensity without materially affecting the basipetal...

  7. Amelioration of Chilling Injuries in Watermelon Seedlings by Abscisic Acid

    Korkmaz, Ahmet

    2002-01-01

    A greenhouse study, designed in a randomized complete block design with five replications, was carried out at Clemson University, Clemson, SC, USA, in the spring of 1997. The objective of the study was to investigate whether abscisic acid (ABA) would mitigate chilling damages in the watermelon, a chilling-sensitive plant. 'Crimson Sweet' [Citrullus lanatus (Thumb) Matsum. & Nakai.] watermelon seedlings were grown in a greenhouse with a temperature regime of 25ºC (day) and 20ºC...

  8. Radioimmunoassay for free and bound forms of abscisic acid

    A radioimmunoassay (RIA) for the quanitation of abscisic acid (ABA) has been developed. The assay is extremely sensitive and measuring ranges extend from 10 pg to 10 ng. Although the assay was free of contaminant interference when applied to avocado material, crude extract analysis yielded a composite of free and bound forms of ABA. Equivalents of 20 mg of plant material were spotted onto silica gel plates (GF245 solvent:toluene:ethyl acetate : acetic acid 25:15:3), developed and the relative Rf zones removed and subjected to RIA. The technique was tested on avocados

  9. MRI in callosal apraxia and agraphia due to a traumatic lesion in the posterior trunk of the corpus callosum

    Yasumura, Shuichi; Ito, Naoki; Terunuma, Hiroshi; Matsuzaki, Takayuki; Iwabuchi, Reiko

    1987-08-01

    We discussed functional topography of the corpus callosum in a case with ideo-motor apraxia and agraphia of the left hand due to a traumatic callosal hematoma confirmed by MRI. The patient was a 35-year-old right-handed woman with head injury in a traffic accident. On admission she was semi-comatose with left oculomotor palsy and her left upper limb showed a decorticate rigidity by noxious stimuli, however, she became alert within 14 days. X-ray CT showed an abnormal high density area in the posterior part of the trunk of the corpus callosum on admission. MRI (inversion recovery technique) on the 60th hospital day showed a low intensity area extending for about 2 cm posteriorly from the center of the trunk. Sequential neuropsychological examinations for the callosal disconnection syndrome were performed. The patient showed ideo-motor apraxia and agraphia in her left hand only. Her response to verbal commands were all parapraxic except for correct use of a comb and a tooth brush. Her writings with her left hand were those of scrawls due to apraxia. These apraxia and agraphia of the left hand were transient and recovered completely within 80 days of onset. Transient impairement of bimanual coordination movement was also observed. Ataxie optique, callosal pseudoneglect, left hand tactile anomia, difficulty of somesthetic transfer or diagonistic dyspraxia was not observed. Based on the neuropsychological and the MRI findings we suggest that the lesion in the posterior part of the trunk of the corpus callosum is important for causing ideo-motor apraxia and agraphia of the left hand.

  10. Normal centrolineal myelination of the callosal splenium reflects the development of the cortical origin and size of its commissural fibers

    Commissural white matter fibers comprising the callosal splenium are diverse. Subsections of the splenium myelinate at different times, in a centrolineal manner. The aims of this study are to depict the normal callosal splenium myelination pattern and to distinguish the transient age-related mid splenium hypointensity from pathology. We reviewed 131 consecutive brain MRIs in patients between ages 3 and 6 months from a single academic children's hospital. Patients that were preterm, hydrocephalic, and/or had volume loss were excluded. Fifty total MR exams that included T1-weighted MR imaging (T1WI), T2-weighted MR imaging (T2WI), and diffusion tensor imaging (DTI) were reviewed. Regions of callosal splenium myelination manifested by T1 and T2 shortening were evaluated. Tractography was performed with seeds placed over the posterior, mid, and anterior splenium to define the origin, destination, and course of traversing fibers. Splenium signal varied significantly from 3 to 6 months, with distinct age-related trends. On T1WI, the splenium was hypointense at 3 months (12/13), centrally hypointense/peripherally hyperintense at 4 months (15/16), and hyperintense at 6 months (10/11). Tractography revealed three distinct white matter tract populations: medial occipital (posterior); precuneus, posterior cingulate, and medial temporal (middle); and postcentral gyri (anterior). Specific commissural fiber components of the splenium myelinate at different times. The transient developmental mid splenium hypointensity on T1WI corresponds to tracts from the associative cortex, principally the precuneus. Heterogeneous splenium signal alteration in patients ages 3-6 months is a normal developmental phenomenon that should not be confused with pathologic lesions. (orig.)

  11. Normal centrolineal myelination of the callosal splenium reflects the development of the cortical origin and size of its commissural fibers

    Whitehead, Matthew T. [University of Tennessee Health Science Center, Department of Radiology, Memphis, TN (United States); Le Bonheur Children' s Hospital, Le Bonheur Neuroscience Institute, Memphis, TN (United States); Children' s National Medical Center, Department of Radiology, Washington, DC (United States); Raju, Anand; Choudhri, Asim F. [University of Tennessee Health Science Center, Department of Radiology, Memphis, TN (United States); Le Bonheur Children' s Hospital, Le Bonheur Neuroscience Institute, Memphis, TN (United States)

    2014-04-15

    Commissural white matter fibers comprising the callosal splenium are diverse. Subsections of the splenium myelinate at different times, in a centrolineal manner. The aims of this study are to depict the normal callosal splenium myelination pattern and to distinguish the transient age-related mid splenium hypointensity from pathology. We reviewed 131 consecutive brain MRIs in patients between ages 3 and 6 months from a single academic children's hospital. Patients that were preterm, hydrocephalic, and/or had volume loss were excluded. Fifty total MR exams that included T1-weighted MR imaging (T1WI), T2-weighted MR imaging (T2WI), and diffusion tensor imaging (DTI) were reviewed. Regions of callosal splenium myelination manifested by T1 and T2 shortening were evaluated. Tractography was performed with seeds placed over the posterior, mid, and anterior splenium to define the origin, destination, and course of traversing fibers. Splenium signal varied significantly from 3 to 6 months, with distinct age-related trends. On T1WI, the splenium was hypointense at 3 months (12/13), centrally hypointense/peripherally hyperintense at 4 months (15/16), and hyperintense at 6 months (10/11). Tractography revealed three distinct white matter tract populations: medial occipital (posterior); precuneus, posterior cingulate, and medial temporal (middle); and postcentral gyri (anterior). Specific commissural fiber components of the splenium myelinate at different times. The transient developmental mid splenium hypointensity on T1WI corresponds to tracts from the associative cortex, principally the precuneus. Heterogeneous splenium signal alteration in patients ages 3-6 months is a normal developmental phenomenon that should not be confused with pathologic lesions. (orig.)

  12. MRI in callosal apraxia and agraphia due to a traumatic lesion in the posterior trunk of the corpus callosum

    We discussed functional topography of the corpus callosum in a case with ideo-motor apraxia and agraphia of the left hand due to a traumatic callosal hematoma confirmed by MRI. The patient was a 35-year-old right-handed woman with head injury in a traffic accident. On admission she was semi-comatose with left oculomotor palsy and her left upper limb showed a decorticate rigidity by noxious stimuli, however, she became alert within 14 days. X-ray CT showed an abnormal high density area in the posterior part of the trunk of the corpus callosum on admission. MRI (inversion recovery technique) on the 60th hospital day showed a low intensity area extending for about 2 cm posteriorly from the center of the trunk. Sequential neuropsychological examinations for the callosal disconnection syndrome were performed. The patient showed ideo-motor apraxia and agraphia in her left hand only. Her response to verbal commands were all parapraxic except for correct use of a comb and a tooth brush. Her writings with her left hand were those of scrawls due to apraxia. These apraxia and agraphia of the left hand were transient and recovered completely within 80 days of onset. Transient impairement of bimanual coordination movement was also observed. Ataxie optique, callosal pseudoneglect, left hand tactile anomia, difficulty of somesthetic transfer or diagonistic dyspraxia was not observed. Based on the neuropsychological and the MRI findings we suggest that the lesion in the posterior part of the trunk of the corpus callosum is important for causing ideo-motor apraxia and agraphia of the left hand. (author)

  13. Tumour–stromal interactions in acid-mediated invasion: A mathematical model

    Martin, Natasha K.

    2010-12-01

    It is well established that the tumour microenvironment can both promote and suppress tumour growth and invasion, however, most mathematical models of invasion view the normal tissue as inhibiting tumour progression via immune modulation or spatial constraint. In particular, the production of acid by tumour cells and the subsequent creation of a low extracellular pH environment has been explored in several \\'acid-mediated tumour invasion\\' models where the acidic environment facilitates normal cell death and permits tumour invasion. In this paper, we extend the acid-invasion model developed by Gatenby and Gawlinski (1996) to include both the competitive and cooperative interactions between tumour and normal cells, by incorporating the influence of extracellular matrix and protease production at the tumour-stroma interface. Our model predicts an optimal level of tumour acidity which produces both cell death and matrix degradation. Additionally, very aggressive tumours prevent protease production and matrix degradation by excessive normal cell destruction, leading to an acellular (but matrix filled) gap between the tumour and normal tissue, a feature seen in encapsulated tumours. These results suggest, counterintuitively, that increasing tumour acidity may, in some cases, prevent tumour invasion.

  14. Poly(methacrylic acid)-mediated morphosynthesis of PbWO{sub 4} micro-crystals

    Yu, J.G.; Zhao, X.F.; Liu, S.W. [Wuhan University of Technology, State Key Lab of Advanced Technology for Materials Synthesis and Processing, Wuhan (China); Li, M.; Mann, S. [University of Bristol, School of Chemistry, Bristol (United Kingdom); Ng, D.H.L. [The Chinese University of Hong Kong, Department of Physics, Hong Kong (China)

    2007-04-15

    PbWO{sub 4} crystals with various morphologies were fabricated via a facile poly(methacrylic acid)-mediated hydrothermal route. Novel microsized PbWO{sub 4} single crystals with a needle-like shape as well as other morphologies, such as a fishbone, dendrite, sphere, spindle, ellipsoid, rod, and dumbbell with two dandelion-like heads, could be produced. The presence of PMAA, [Pb{sup 2+}]/[WO{sub 4} {sup 2-}] molar ratio (R), and aging temperature played key roles in the formation of the PbWO{sub 4} needle-like structures. Between temperatures of 60 to 150 C, the length and photoluminescence intensities of the PbWO{sub 4} micro needles significantly increased with aging temperature, while the diameter did not change remarkably. Time-dependent experiments revealed that the formation of PbWO{sub 4} microneedles involved an unusual growth process, involving nucleation, oriented assembly and controlled mesoscale restructuring of nanoparticle building blocks. (orig.)

  15. A family of conserved bacterial effectors inhibits salicylic acid-mediated basal immunity and promotes disease necrosis in plants.

    DebRoy, Sruti; Thilmony, Roger; Kwack, Yong-Bum; Nomura, Kinya; He, Sheng Yang

    2004-06-29

    Salicylic acid (SA)-mediated host immunity plays a central role in combating microbial pathogens in plants. Inactivation of SA-mediated immunity, therefore, would be a critical step in the evolution of a successful plant pathogen. It is known that mutations in conserved effector loci (CEL) in the plant pathogens Pseudomonas syringae (the Delta CEL mutation), Erwinia amylovora (the dspA/E mutation), and Pantoea stewartii subsp. stewartii (the wtsE mutation) exert particularly strong negative effects on bacterial virulence in their host plants by unknown mechanisms. We found that the loss of virulence in Delta CEL and dspA/E mutants was linked to their inability to suppress cell wall-based defenses and to cause normal disease necrosis in Arabidopsis and apple host plants. The Delta CEL mutant activated SA-dependent callose deposition in wild-type Arabidopsis but failed to elicit high levels of callose-associated defense in Arabidopsis plants blocked in SA accumulation or synthesis. This mutant also multiplied more aggressively in SA-deficient plants than in wild-type plants. The hopPtoM and avrE genes in the CEL of P. syringae were found to encode suppressors of this SA-dependent basal defense. The widespread conservation of the HopPtoM and AvrE families of effectors in various bacteria suggests that suppression of SA-dependent basal immunity and promotion of host cell death are important virulence strategies for bacterial infection of plants. PMID:15210989

  16. Arabidopsis YAK1 regulates abscisic acid response and drought resistance.

    Kim, Dongjin; Ntui, Valentine Otang; Xiong, Liming

    2016-07-01

    Abscisic acid (ABA) is an important phytohormone that controls several plant processes such as seed germination, seedling growth, and abiotic stress response. Here, we report that AtYak1 plays an important role in ABA signaling and postgermination growth in Arabidopsis. AtYak1 knockout mutant plants were hyposensitive to ABA inhibition of seed germination, cotyledon greening, seedling growth, and stomatal movement. atyak1-1 mutant plants display reduced drought stress resistance, as evidenced by water loss rate and survival rate. Molecular genetic analysis revealed that AtYak1 deficiency led to elevated expression of stomatal-related gene, MYB60, and down-regulation of several stress-responsive genes. Altogether, these results indicate that AtYak1 plays a role as a positive regulator in ABA-mediated drought response in Arabidopsis. PMID:27264339

  17. Radioimmunoassay for the determination of free and conjugated abscisic acid

    The characterization and application of a radioimmunoassay specific for free and conjugated abscisic acid (ABA) is reported, The antibodies produced against a bovine serum albumin-(+-)-ABA conjugate have a high affinity for ABA (Ka= 1.3 x 109 l mol-1). Trans, trans-ABA and related compounds, such as xanthoxin, phaseic acid, dihydrophaseic acid, vomifoliol or violaxanthin do not interfere with the assay. The detection limit of this method is 0.25 x 10-12 mol ABA, the measuring range extends to 20 x 10-12 mol, and average recoveries are 103%. Because of the high specificity of this immunoassay, no extract purification steps are required prior to analysis. Several hundred plants can be analyzed per day in a semi-automatic assay performance. ABA has been detected in all higher plant families examined, but was absent in the blue-green alga, Spirulina platensis, the liverwort Marchantia polymorpha, and two species of fungi. (orig.)

  18. Characterization and Functional Analysis of Pyrabactin Resistance-Like Abscisic Acid Receptor Family in Rice

    Tian, Xiaojie; Wang, Zhenyu; Li, Xiufeng; Lv, Tianxiao; Liu, Huazhao; Wang, Lizhi; Niu, Hongbin; Bu, Qingyun

    2015-01-01

    Background Abscisic acid (ABA) plays crucial roles in regulating plant growth and development, especially in responding to abiotic stress. The pyrabactin resistance-like (PYL) abscisic acid receptor family has been identified and widely characterized in Arabidopsis. However, PYL families in rice were largely unknown. In the present study, 10 out of 13 PYL orthologs in rice (OsPYL) were isolated and investigated. Results Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) an...

  19. A Direct, Biomass-Based Synthesis of Benzoic Acid: Formic Acid-Mediated Deoxygenation of the Glucose-Derived Materials Quinic Acid and Shikimic Acid

    Arceo, Elena; Ellman, Jonathan; Bergman, Robert

    2010-05-03

    An alternative biomass-based route to benzoic acid from the renewable starting materials quinic acid and shikimic acid is described. Benzoic acid is obtained selectively using a highly efficient, one-step formic acid-mediated deoxygenation method.

  20. Abscisic Acid and Abiotic Stress Tolerance in Crop Plants

    Sah, Saroj K.; Reddy, Kambham R.; Li, Jiaxu

    2016-01-01

    Abiotic stress is a primary threat to fulfill the demand of agricultural production to feed the world in coming decades. Plants reduce growth and development process during stress conditions, which ultimately affect the yield. In stress conditions, plants develop various stress mechanism to face the magnitude of stress challenges, although that is not enough to protect them. Therefore, many strategies have been used to produce abiotic stress tolerance crop plants, among them, abscisic acid (ABA) phytohormone engineering could be one of the methods of choice. ABA is an isoprenoid phytohormone, which regulates various physiological processes ranging from stomatal opening to protein storage and provides adaptation to many stresses like drought, salt, and cold stresses. ABA is also called an important messenger that acts as the signaling mediator for regulating the adaptive response of plants to different environmental stress conditions. In this review, we will discuss the role of ABA in response to abiotic stress at the molecular level and ABA signaling. The review also deals with the effect of ABA in respect to gene expression. PMID:27200044

  1. Abscisic acid and pyrabactin improve vitamin C contents in raspberries.

    Miret, Javier A; Munné-Bosch, Sergi

    2016-07-15

    Abscisic acid (ABA) is a plant growth regulator with roles in senescence, fruit ripening and environmental stress responses. ABA and pyrabactin (a non-photosensitive ABA agonist) effects on red raspberry (Rubus idaeus L.) fruit development (including ripening) were studied, with a focus on vitamin and antioxidant composition. Application of ABA and/or pyrabactin just after fruit set did not affect the temporal pattern of fruit development and ripening; neither provitamin A (carotenoids) nor vitamin E contents were modified. In contrast, ABA and pyrabactin altered the vitamin C redox state at early stages of fruit development and more than doubled vitamin C contents at the end of fruit ripening. These were partially explained by changes in ascorbate oxidation and recycling. Therefore, ABA and pyrabactin applications may be used to increase vitamin C content of ripe fruits, increasing fruit quality and value. However, treatments containing pyrabactin-combined with ABA or alone-diminished protein content, thus partially limiting its potential applicability. PMID:26948608

  2. Compartmentation and equilibration of abscisic acid in isolated Xanthium cells

    Bray, E.A.; Zeevaart, J.A.D.

    1986-01-01

    The compartmentation of endogenous abscisic acid (ABA), applied (+/-)-(/sup 3/H)ABA, and (+/-)-trans-ABA was measured in isolated mesophyll cells of the Chicago strain of Xanthium strumarium L. The release of ABA to the medium in the presence or absence of DMSO was used to determine the equilibration of ABA in the cells. It was found that a greater percentage of the (+/-)-(/sup 3/H)ABA and the (+/-)-trans-ABA was released into the medium than of the endogenous ABA, indicating that applied ABA did not equilibrate with the endogenous material. Therefore, in further investigations only the compartmentation of endogenous ABA was studied. Endogenous ABA was released from Xanthium cells according to the pH gradients among the various cellular compartments. Thus, darkness, high external pH, KNO/sub 2/, and drought-stress all increased the efflux of ABA from the cells. Efflux of ABA from the cells in the presence of 0.6 M mannitol occurred within 30 seconds, but only 8% of the endogenous material was released during the 20 minute treatment.

  3. Effects of mechanical stress or abscisic acid on growth, water status and leaf abscisic acid content of eggplant seedlings

    Latimer, J. G.; Mitchell, C. A.

    1988-01-01

    Container-grown eggplant (Solanum melongena L. var esculentum Nees. 'Burpee's Black Beauty') seedlings were conditioned with brief, periodic mechanical stress or abscisic acid (ABA) in a greenhouse prior to outdoor exposure. Mechanical stress consisted of seismic (shaking) or thigmic (stem flexing) treatment. Exogenous ABA (10(-3) or 10(-4)M) was applied as a soil drench 3 days prior to outdoor transfer. During conditioning, only thigmic stress reduced stem elongation and only 10(-3) M ABA reduced relative growth rate (RGR). Both conditioning treatments increased leaf specific chlorophyll content, but mechanical stress did not affect leaf ABA content. Outdoor exposure of unconditioned eggplant seedlings decreased RGR and leaf-specific chlorophyll content, but tended to increase leaf ABA content relative to that of plants maintained in the greenhouse. Conditioning did not affect RGR of plants subsequently transferred outdoors, but did reduce stem growth. Seismic stress applied in the greenhouse reduced dry weight gain by plants subsequently transferred outdoors. Mechanical stress treatments increased leaf water potential by 18-25% relative to that of untreated plants.

  4. Analysis of YFP(J16)-R6/2 reporter mice and postmortem brains reveals early pathology and increased vulnerability of callosal axons in Huntington's disease.

    Gatto, Rodolfo G; Chu, Yaping; Ye, Allen Q; Price, Steven D; Tavassoli, Ehsan; Buenaventura, Andrea; Brady, Scott T; Magin, Richard L; Kordower, Jeffrey H; Morfini, Gerardo A

    2015-09-15

    Cumulative evidence indicates that the onset and severity of Huntington's disease (HD) symptoms correlate with connectivity deficits involving specific neuronal populations within cortical and basal ganglia circuits. Brain imaging studies and pathological reports further associated these deficits with alterations in cerebral white matter structure and axonal pathology. However, whether axonopathy represents an early pathogenic event or an epiphenomenon in HD remains unknown, nor is clear the identity of specific neuronal populations affected. To directly evaluate early axonal abnormalities in the context of HD in vivo, we bred transgenic YFP(J16) with R6/2 mice, a widely used HD model. Diffusion tensor imaging and fluorescence microscopy studies revealed a marked degeneration of callosal axons long before the onset of motor symptoms. Accordingly, a significant fraction of YFP-positive cortical neurons in YFP(J16) mice cortex were identified as callosal projection neurons. Callosal axon pathology progressively worsened with age and was influenced by polyglutamine tract length in mutant huntingtin (mhtt). Degenerating axons were dissociated from microscopically visible mhtt aggregates and did not result from loss of cortical neurons. Interestingly, other axonal populations were mildly or not affected, suggesting differential vulnerability to mhtt toxicity. Validating these results, increased vulnerability of callosal axons was documented in the brains of HD patients. Observations here provide a structural basis for the alterations in cerebral white matter structure widely reported in HD patients. Collectively, our data demonstrate a dying-back pattern of degeneration for cortical projection neurons affected in HD, suggesting that axons represent an early and potentially critical target for mhtt toxicity. PMID:26123489

  5. Study of endogenic abscisic acids and cytokinin content in soybean crops of variable salt sensitivity as well as the effect of exogenically applied abscisic acid on Cl/sup -/ translocation. [in German

    Roeb, G.

    1981-05-01

    A study of the phytohormones abscisic acid and cytokinin with respect to plant salt stress and its relationship to genetic control over endogen content. An analysis is made of the acid cytokinin content, and an investigation is made of the influence exerted by exogenic applied synthetic abscisic acid on Cl/sup -/ uptake and accumulation. 275 references, 14 figures, 11 tables.

  6. Analysis of the plant hormones Abscisic acid and Xanthoxin in trees of the two stands No. 79 and 109 in the Hils

    Majcherczyk, A.; Huettermann, A.

    1984-01-01

    Pilca abies of two different treations were compared. The phytohormones Abscisic acid and Xanthoxin were analysed. The role and the content of abscisic acid and Xanthoxin in trees under stress induced by acid rain were investigated.

  7. Characterization of major ripening events during softening in grape: turgor, sugar accumulation, abscisic acid metabolism, colour development, and their relationship with growth

    Castellarin, Simone D.; Gambetta, Gregory A.; Wada, Hiroshi; Krasnow, Mark N.; Cramer, Grant R.; Peterlunger, Enrico; Shackel, Kenneth A.; Matthews, Mark A.

    2015-01-01

    Highlight The earliest events in ripening are decreases in turgor, softening, and increases in abscisic acid. Later events integral to regulating colour development include growth, further increases in abscisic acid, and sugar accumulation.

  8. Transcriptional Responses to Gibberellin and Abscisic Acid in Barley Aleurone

    Kegui Chen; Yong-Qiang Charles An

    2006-01-01

    Cereal aleurone has been established as a model system to investigate giberrellin (GA) and abscisic acid (ABA) responses. Using Barley 1 GeneChip, we examined the mRNA accumulation of over 22 000 genes in de-embryonated barley aleurone treated with GA and ABA. We observed that 1328 genes had more than a threefold change in response to GA treatment, whereas 206 genes had a more than threefold change in response to ABA treatment. Interestingly, approximately 2.5-fold more genes were up-regulated than downregulated by ABA. Eighty-three genes were differentially regulated by both GA and ABA. Most of the genes were subject to antagonistic regulation by ABA and GA, particularly for genes related to seed maturation and germination, such as genes encoding late embryogenesis abundant proteins and storage mobilization enzymes. This supports the antagonistic roles of GA and ABA in seed maturation and seed germination.Interestingly, we observed that a significant percentage of the genes were coordinately regulated by both GA and ABA. Some GA-responsive genes encoded proteins involved in ethylene, jasmonate, brassinosteroid and auxin metabolic and signaling transduction pathways, suggesting their potential interaction with the GA response. We also identified a group of transcription factor genes, such as MYB and Homeobox genes, that were differentially regulated by GA. In addition, a number of GA- and/or ABA-responsive genes encoded components potentially involved in GA and ABA signal transduction pathway. Overall, the present study provides a comprehensive and global view of transcript expression accompanying the GA and ABA response in barley aleurone and identifies a group of genes with potential regulatory functions in GA- and ABA-signaling pathways for future functional validation.

  9. Abscisic acid ameliorates the systemic sclerosis fibroblast phenotype in vitro

    Bruzzone, Santina, E-mail: santina.bruzzone@unige.it [Department of Experimental Medicine, Section of Biochemistry, University of Genova, Viale Benedetto XV 1, 16132 Genova (Italy); Centre of Excellence for Biomedical Research, University of Genova, Viale Benedetto XV 9, 16132 Genova (Italy); Advanced Biotechnology Center, Largo Rosanna Benzi 10, 16132 Genova (Italy); Battaglia, Florinda [Centre of Excellence for Biomedical Research, University of Genova, Viale Benedetto XV 9, 16132 Genova (Italy); Mannino, Elena [Department of Experimental Medicine, Section of Biochemistry, University of Genova, Viale Benedetto XV 1, 16132 Genova (Italy); Parodi, Alessia [Centre of Excellence for Biomedical Research, University of Genova, Viale Benedetto XV 9, 16132 Genova (Italy); Fruscione, Floriana [Department of Experimental Medicine, Section of Biochemistry, University of Genova, Viale Benedetto XV 1, 16132 Genova (Italy); Advanced Biotechnology Center, Largo Rosanna Benzi 10, 16132 Genova (Italy); Basile, Giovanna [Department of Experimental Medicine, Section of Biochemistry, University of Genova, Viale Benedetto XV 1, 16132 Genova (Italy); Salis, Annalisa; Sturla, Laura [Department of Experimental Medicine, Section of Biochemistry, University of Genova, Viale Benedetto XV 1, 16132 Genova (Italy); Centre of Excellence for Biomedical Research, University of Genova, Viale Benedetto XV 9, 16132 Genova (Italy); Negrini, Simone; Kalli, Francesca; Stringara, Silvia [Centre of Excellence for Biomedical Research, University of Genova, Viale Benedetto XV 9, 16132 Genova (Italy); Filaci, Gilberto [Centre of Excellence for Biomedical Research, University of Genova, Viale Benedetto XV 9, 16132 Genova (Italy); Department of Internal Medicine, Viale Benedetto XV 6, 16132 Genova (Italy); and others

    2012-05-25

    Highlights: Black-Right-Pointing-Pointer ABA is an endogenous hormone in humans, regulating different cell responses. Black-Right-Pointing-Pointer ABA reverts some of the functions altered in SSc fibroblasts to a normal phenotype. Black-Right-Pointing-Pointer UV-B irradiation increases ABA content in SSc cultures. Black-Right-Pointing-Pointer SSc fibroblasts could benefit from exposure to ABA and/or to UV-B. -- Abstract: The phytohormone abscisic acid (ABA) has been recently identified as an endogenous hormone in humans, regulating different cell functions, including inflammatory processes, insulin release and glucose uptake. Systemic sclerosis (SSc) is a chronic inflammatory disease resulting in fibrosis of skin and internal organs. In this study, we investigated the effect of exogenous ABA on fibroblasts obtained from healthy subjects and from SSc patients. Migration of control fibroblasts induced by ABA was comparable to that induced by transforming growth factor-{beta} (TGF-{beta}). Conversely, migration toward ABA, but not toward TGF-{beta}, was impaired in SSc fibroblasts. In addition, ABA increased cell proliferation in fibroblasts from SSc patients, but not from healthy subjects. Most importantly, presence of ABA significantly decreased collagen deposition by SSc fibroblasts, at the same time increasing matrix metalloproteinase-1 activity and decreasing the expression level of tissue inhibitor of metalloproteinase (TIMP-1). Thus, exogenously added ABA appeared to revert some of the functions altered in SSc fibroblasts to a normal phenotype. Interestingly, ABA levels in plasma from SSc patients were found to be significantly lower than in healthy subjects. UV-B irradiation induced an almost 3-fold increase in ABA content in SSc cultures. Altogether, these results suggest that the fibrotic skin lesions in SSc patients could benefit from exposure to high(er) ABA levels.

  10. In vitro reconstitution of an abscisic acid signalling pathway

    Fujii, Hiroaki

    2009-11-18

    The phytohormone abscisic acid (ABA) regulates the expression of many genes in plants; it has critical functions in stress resistance and in growth and development. Several proteins have been reported to function as ABA receptors, and many more are known to be involved in ABA signalling. However, the identities of ABA receptors remain controversial and the mechanism of signalling from perception to downstream gene expression is unclear. Here we show that by combining the recently identified ABA receptor PYR1 with the type 2C protein phosphatase (PP2C) ABI1, the serine/threonine protein kinase SnRK2.6/OST1 and the transcription factor ABF2/AREB1, we can reconstitute ABA-triggered phosphorylation of the transcription factor in vitro. Introduction of these four components into plant protoplasts results in ABA-responsive gene expression. Protoplast and test-tube reconstitution assays were used to test the function of various members of the receptor, protein phosphatase and kinase families. Our results suggest that the default state of the SnRK2 kinases is an autophosphorylated, active state and that the SnRK2 kinases are kept inactive by the PP2Cs through physical interaction and dephosphorylation. We found that in the presence of ABA, the PYR/PYL (pyrabactin resistance 1/PYR1-like) receptor proteins can disrupt the interaction between the SnRK2s and PP2Cs, thus preventing the PP2C-mediated dephosphorylation of the SnRK2s and resulting in the activation of the SnRK2 kinases. Our results reveal new insights into ABA signalling mechanisms and define a minimal set of core components of a complete major ABA signalling pathway. © 2009 Macmillan Publishers Limited. All rights reserved.

  11. Plant water stress: Associations between ethylene and abscisic acid response

    Carolina Salazar

    2015-08-01

    Full Text Available Agriculture is severely impacted by water stress due either to excess (hypoxia/anoxia or deficit of water availability. Hypoxia/anoxia is associated with oxygen (O2 deficiency or depletion, inducing several anatomical, morphological, physiological, and molecular changes. The majority of these alterations are adaptive mechanisms to cope with low O2 availability; among them, alterations in shoot length, aerenchyma formation and adventitious roots have been described in several studies. The aim of this review was to address the association between abscisic acid (ABA and ethylene in function of water availability in plants. The major physiological responses to low O2 are associated with changes in root respiration, stomatal conductance, photosynthesis, and fermentation pathways in roots. In addition, several changes in gene expression have been associated with pathways that are not present under normal O2 supply. The expression of ethylene receptor genes is up-regulated by low O2, and ethylene seems to have a crucial role in anatomical and physiological effects during hypoxia/anoxia. During O2 depletion, ethylene accumulation down-regulates ABA by inhibiting rate-limiting enzymes in ABA biosynthesis and by activating ABA breakdown to phaseic acid. With regard to water deficit, drought is primarily sensed by the roots, inducing a signal cascade to the shoots via xylem causing physiological and morphological changes. Several genes are regulated up or down with osmotic stress; the majority of these responsive genes can be driven by either an ABA-dependent or ABA-independent pathway. Some studies suggest that ethylene shuts down leaf growth very fast after the plant senses limited water availability. Ethylene accumulation can antagonize the control of gas exchange and leaf growth upon drought and ABA accumulation.

  12. Abscisic acid ameliorates the systemic sclerosis fibroblast phenotype in vitro

    Highlights: ► ABA is an endogenous hormone in humans, regulating different cell responses. ► ABA reverts some of the functions altered in SSc fibroblasts to a normal phenotype. ► UV-B irradiation increases ABA content in SSc cultures. ► SSc fibroblasts could benefit from exposure to ABA and/or to UV-B. -- Abstract: The phytohormone abscisic acid (ABA) has been recently identified as an endogenous hormone in humans, regulating different cell functions, including inflammatory processes, insulin release and glucose uptake. Systemic sclerosis (SSc) is a chronic inflammatory disease resulting in fibrosis of skin and internal organs. In this study, we investigated the effect of exogenous ABA on fibroblasts obtained from healthy subjects and from SSc patients. Migration of control fibroblasts induced by ABA was comparable to that induced by transforming growth factor-β (TGF-β). Conversely, migration toward ABA, but not toward TGF-β, was impaired in SSc fibroblasts. In addition, ABA increased cell proliferation in fibroblasts from SSc patients, but not from healthy subjects. Most importantly, presence of ABA significantly decreased collagen deposition by SSc fibroblasts, at the same time increasing matrix metalloproteinase-1 activity and decreasing the expression level of tissue inhibitor of metalloproteinase (TIMP-1). Thus, exogenously added ABA appeared to revert some of the functions altered in SSc fibroblasts to a normal phenotype. Interestingly, ABA levels in plasma from SSc patients were found to be significantly lower than in healthy subjects. UV-B irradiation induced an almost 3-fold increase in ABA content in SSc cultures. Altogether, these results suggest that the fibrotic skin lesions in SSc patients could benefit from exposure to high(er) ABA levels.

  13. Microstructural callosal abnormalities in normal-appearing brain of children with developmental delay detected with diffusion tensor imaging

    Callosal fibres play an important role in psychomotor and cognitive functions. The purpose of this study was to investigate possible microstructural abnormalities of the corpus callosum in children with developmental delay, who have normal conventional brain MR imaging results. Seventeen pediatric patients (aged 1-9 years) with developmental delay were studied. Quantitative T2 and fractional anisotropy (FA) values were measured at the genu and splenium of the corpus callosum (CC). Fibre tracking, volumetric determination, as well as fibre density calculations of the CC were also carried out. The results were compared with those of the age-matched healthy subjects. A general elevation of T2 relaxation times (105 ms in patients vs. 95 ms in controls) and reduction of the FA values (0.66 in patients vs. 0.74 in controls) at the genu of the CC were found in patients. Reductions of the fibre numbers (5,464 in patients vs. 8,886 in controls) and volumes (3,415 ml in patients vs. 5,235 ml in controls) of the CC were found only in patients older than 5 years. The study indicates that despite their inconspicuous findings in conventional MRI microstructural brain abnormalities are evident in these pediatric patients suffering from developmental delay. (orig.)

  14. Microstructural callosal abnormalities in normal-appearing brain of children with developmental delay detected with diffusion tensor imaging

    Ding, Xiao-Qi [Hannover Medical School, Institute of Diagnostic and Interventional Neuroradiology, Hannover (Germany); University Medical Center Hamburg-Eppendorf, Department of Neuroradiology, Hamburg (Germany); Sun, Yimeng; Illies, Till; Zeumer, Hermann; Fiehler, Jens [University Medical Center Hamburg-Eppendorf, Department of Neuroradiology, Hamburg (Germany); Kruse, Bernd [University Medical Center Hamburg-Eppendorf, Department of Pediatrics, Hamburg (Germany); Lanfermann, Heinrich [Hannover Medical School, Institute of Diagnostic and Interventional Neuroradiology, Hannover (Germany)

    2009-06-15

    Callosal fibres play an important role in psychomotor and cognitive functions. The purpose of this study was to investigate possible microstructural abnormalities of the corpus callosum in children with developmental delay, who have normal conventional brain MR imaging results. Seventeen pediatric patients (aged 1-9 years) with developmental delay were studied. Quantitative T2 and fractional anisotropy (FA) values were measured at the genu and splenium of the corpus callosum (CC). Fibre tracking, volumetric determination, as well as fibre density calculations of the CC were also carried out. The results were compared with those of the age-matched healthy subjects. A general elevation of T2 relaxation times (105 ms in patients vs. 95 ms in controls) and reduction of the FA values (0.66 in patients vs. 0.74 in controls) at the genu of the CC were found in patients. Reductions of the fibre numbers (5,464 in patients vs. 8,886 in controls) and volumes (3,415 ml in patients vs. 5,235 ml in controls) of the CC were found only in patients older than 5 years. The study indicates that despite their inconspicuous findings in conventional MRI microstructural brain abnormalities are evident in these pediatric patients suffering from developmental delay. (orig.)

  15. Abscisic acid biosynthesis in leaves and roots of Xanthium strumarium

    Creelman, R.A.; Gage, D.A.; Stults, J.T.; Zeevaart, J.A.D.

    1987-11-01

    Research on the biosynthesis of abscisic acid (ABA) has focused primarily on two pathways: (a) the direct pathway from farnesyl pyrophosphate, and (b) the indirect pathway involving a carotenoid precursor. The authors have investigated which biosynthetic pathway is operating in turgid and stressed Xanthium leaves, and in stressed Xanthium roots using long-term incubations in /sup 18/O/sub 2/. It was found that in stressed leaves three atoms of /sup 18/O from /sup 18/O/sub 2/ are incorporated into the ABA molecule, and that the amount of /sup 18/O incorporated increases with time. One /sup 18/O atom is incorporated rapidly into the carboxyl group of ABA, whereas the other two atoms are very slowly incorporated into the ring oxygens. The fourth oxygen atom in the carboxyl group of ABA is derived from water. ABA from stressed roots of Xanthium incubated in /sup 18/O/sub 2/ shows a labeling pattern similar to that of ABA in stressed leaves, but with incorporation of more /sup 18/O into the tertiary hydroxyl group at C-1' after 6 and 12 hours than found in ABA from stressed leaves. It is proposed that the precursors to stress-induced ABA are xanthophylls, and that a xanthophyll lacking an oxygen function at C-6 plays a crucial role in ABA biosynthesis in Xanthium roots. In turgid Xanthium leaves, /sup 18/O is incorporated into ABA to a much lesser extent that it is in stressed leaves, whereas exogenously applied /sup 14/C-ABA is completely catabolized within 48 hours. This suggests that ABA in turgid leaves is either (a) made via a biosynthetic pathway which is different from the one in stressed leaves, or (b) has a half-life on the order of days as compared with a half-life of 15.5 hours in water-stressed Xanthium leaves. Phaseic acid showed a labeling pattern similar to that of ABA, but with an additional /sup 18/O incorporated during 8'-hydroxylation of ABA to phaseic acid.

  16. Nonlinear stability of a heterogeneous state in a PDE-ODE model for acid-mediated tumor invasion.

    Tao, Youshan; Tello, J Ignacio

    2016-02-01

    This work studies a general reaction-diffusion model for acid-mediated tumor invasion, where tumor cells produce excess acid that primarily kills healthy cells, and thereby invade the microenvironment. The acid diffuses and could be cleared by vasculature, and the healthy and tumor cells are viewed as two species following logistic growth with mutual competition. A key feature of this model is the density-limited diffusion for tumor cells, reflecting that a healthy tissue will spatially constrain a tumor unless shrunk. Under appropriate assumptions on model parameters and on initial data, it is shown that the unique heterogeneous state is nonlinearly stable, which implies a long-term coexistence of the healthy and tumor cells in certain parameter space. Our theoretical result suggests that acidity may play a significant role in heterogeneous tumor progression. PMID:26776259

  17. Interactions between abscisic acid and cytokinins during water stress and subsequent rehydration

    Pospíšilová, Jana; Vágner, Martin; Malbeck, Jiří; Trávníčková, Alena; Baťková, Petra

    2005-01-01

    Roč. 49, - (2005), s. 533-540. ISSN 0006-3134 R&D Projects: GA ČR GA522/02/1099; GA AV ČR(CZ) IAA638105 Institutional research plan: CEZ:AV0Z50380511 Keywords : abscisic acid * cytokinins * water stress Subject RIV: EF - Botanics Impact factor: 0.792, year: 2005

  18. Plant Responses to Water Stress as Affected by Abscisic Acid and Benzyladenine

    Pospíšilová, Jana; Haisel, Daniel; Schnablová, Renáta; Synková, Helena; Baťková, Petra

    Montreal : International Society of Photosynthesis , 2005 - (Van der Est, A.; Bruce, D.), s. 593-595 R&D Projects: GA ČR GA522/02/1099 Institutional research plan: CEZ:AV0Z50380511 Keywords : abscisic acid * benzyladenine * chlorophyl content Subject RIV: ED - Physiology

  19. Effects of high night temperature and abscisic acid (ABA) on rice (Oryza sativa L.) physiology

    High night temperature (HNT) is known to decrease rice yields. The impact of abscisic acid (ABA) on plants has been the subject of many studies. However, little or no work has been carried out on rice response to ABA under HNT-stress conditions. This study determined the effects of ABA on rice leaf ...

  20. Solar sterilization of abscised fruit: a cultural practice to reduce infestations of Anastrepha obliqua around orchards

    Abscised mangoes, Mangifera indica L., of several varieties were stored under varying conditions of insolation, including no sun (stored in a laboratory), shade (stored under the shade of a mango tree), full sun (stored in direct view of the sun), and covered in a black plastic bag and stored in dir...

  1. Endogenous cytokinins, auxins, and abscisic acid in red algae from Brazil

    Yokoya, N. S.; Stirk, W. A.; van Staden, J.; Novák, Ondřej; Turečková, Veronika; Pěnčík, Aleš; Strnad, Miroslav

    2010-01-01

    Roč. 46, č. 6 (2010), s. 1198-1205. ISSN 0022-3646 R&D Projects: GA ČR GA301/08/1649 Institutional research plan: CEZ:AV0Z50380511 Keywords : ENDOGENOUS * CYTOKININS * AUXINS * ABSCISIC ACID * RED * ALGAE * BRAZIL Subject RIV: EF - Botanics Impact factor: 2.239, year: 2010

  2. Diurnal variation of cytokinin, auxin and abscisic acid levels in tobacco leaves

    Nováková, Marie; Motyka, Václav; Dobrev, Petre; Malbeck, Jiří; Gaudinová, Alena

    2005-01-01

    Roč. 56, č. 421 (2005), s. 2877-2883. ISSN 0022-0957 R&D Projects: GA ČR GA206/03/0369; GA MŠk LN00A081 Institutional research plan: CEZ:AV0Z50380511 Keywords : abscisic acid * auxin * cytokinin Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 3.336, year: 2005

  3. Sr36- and Sr5-Mediated Resistance Response to Puccinia graminis f. sp. tritici Is Associated with Callose Deposition in Wheat Guard Cells.

    Wang, X; McCallum, B D; Fetch, T; Bakkeren, G; Saville, B J

    2015-06-01

    Race-specific resistance of wheat to Puccinia graminis f. sp. tritici is primarily posthaustorial and often involves the induction of a hypersensitive response (HR). The aim of this study was to investigate host defense responses induced in interactions between P. graminis f. sp. tritici races and wheat lines carrying different race-specific stem rust resistance (Sr) genes. In incompatible interactions between wheat lines carrying Sr36 in three genetic backgrounds (LMPG, Prelude, or W2691) and avirulent P. graminis f. sp. tritici races MCCFC or RCCDM, callose accumulated within 24 h in wheat guard cells contacted by a P. graminis f. sp. tritici appressorium, and P. graminis f. sp. tritici ingress was inhibited following appressorium formation. Accordingly, the expression of transcripts encoding a callose synthase increased in the incompatible interaction between LMPG-Sr36 and avirulent P. graminis f. sp. tritici race MCCFC. Furthermore, the inhibition of callose synthesis through the infiltration of 2-deoxy-D-glucose (DDG) increased the ability of P. graminis f. sp. tritici race MCCFC to infect LMPG-Sr36. A similar induction of callose deposition in wheat guard cells was also observed within 24 h after inoculation (hai) with avirulent P. graminis f. sp. tritici race HKCJC on LMPG-Sr5 plants. In contrast, this defense response was not induced in incompatible interactions involving Sr6, Sr24, or Sr30. Instead, the induction of an HR and cellular lignification were noted. The manifestation of the HR and cellular lignification was induced earlier (24 hai) and was more extensive in the resistance response mediated by Sr6 compared with those mediated by Sr24 or Sr30. These results indicate that the resistance mediated by Sr36 is similar to that mediated by Sr5 but different from those triggered by Sr6, Sr24, or Sr30. Resistance responses mediated by Sr5 and Sr36 are prehaustorial, and are a result of very rapid recognition of molecules derived from avirulent isolates of

  4. Response of cytokinin pool and cytokinin oxidase/dehydrogenase activity to abscisic acid exhibits organ specificity in peas

    Vaseva, I.; Todorova, D.; Malbeck, Jiří; Trávníčková, Alena; Macháčková, Ivana

    2008-01-01

    Roč. 30, č. 2 (2008), s. 151-155. ISSN 0137-5881 Institutional research plan: CEZ:AV0Z50380511 Keywords : Abscisic acid * Cytokinins * Cytokinin Subject RIV: EF - Botanics Impact factor: 0.807, year: 2008

  5. Acid-mediated reactions under microfluidic conditions: A new strategy for practical synthesis of biofunctional natural products

    Katsunori Tanaka

    2009-08-01

    Full Text Available Microfluidic conditions were applied to acid-mediated reactions, namely, glycosylation, reductive opening of the benzylidene acetal groups, and dehydration, which are the keys to the practical synthesis of N-glycans and the immunostimulating natural product, pristane. A distinctly different reactivity from that in conventional batch stirring was found; the vigorous micromixing of the reactants with the concentrated acids is critical especially for the “fast” reactions to be successful. Such a common feature might be due to the integration of all favorable aspects of microfluidic conditions, i.e., efficient mixing, precise temperature control, and the easy handling of the reactive intermediate by controlling the residence time. The microfluidic reactions cited in this review indicate the need to reinvestigate the traditional or imaginary reactions which have so far been performed and evaluated only in batch apparatus, and therefore they could be recognized as a new strategy in synthesizing natural products of prominent biological activity in a “practical” and a “industrial” manner.

  6. Starch and sucrose synthesis in Phaseolus vulgaris as affected by light, CO2, and abscisic acid

    Phaseolus vulgaris L. leaves were subjected to various light, CO2, and O2 levels and abscisic acid, then given a 10 minute pulse of 14CO2 followed by a 5 minute chase with unlabeled CO2. After the chase period, very little label remained in the ionic fractions except at low CO2 partial pressure. Most label was found in the neutral, alcohol soluble fraction or in the insoluble fraction digestable by amyloglucosidase. Sucrose formation was linearly related to assimilation rate. Starch formation increased linearly with assimilation rate, but did not occur if the assimilation rate was below 4 micromoles per square meter per second. Neither abscisic acid, nor high CO2 in combination with low O2 caused significant perturbations of the sucrose/starch formation ratio. These studies indicate that the pathways for starch and sucrose synthesis both are controlled by the rate of net CO2 assimilation, with sucrose the preferred product at very low assimilation rates

  7. Crucial Roles of Abscisic Acid Biogenesis in Virulence of Rice Blast Fungus Magnaporthe oryzae

    Spence, Carla A.; Lakshmanan, Venkatachalam; Donofrio, Nicole; Bais, Harsh P.

    2015-01-01

    Rice suffers dramatic yield losses due to blast pathogen Magnaporthe oryzae. Pseudomonas chlororaphis EA105, a bacterium that was isolated from the rice rhizosphere, inhibits M. oryzae. It was shown previously that pre-treatment of rice with EA105 reduced the size of blast lesions through jasmonic acid (JA)- and ethylene (ETH)-mediated ISR. Abscisic acid (ABA) acts antagonistically toward salicylic acid (SA), JA, and ETH signaling, to impede plant defense responses. EA105 may be reducing the ...

  8. Karrikins delay soybean seed germination by mediating abscisic acid and gibberellin biogenesis under shaded conditions

    Yongjie Meng; Feng Chen; Haiwei Shuai; Xiaofeng Luo; Jun Ding; Shengwen Tang; Shuanshuan Xu; Jianwei Liu; Weiguo Liu; Junbo Du; Jiang Liu; Feng Yang; Xin Sun; Taiwen Yong; Xiaochun Wang

    2016-01-01

    Karrikins (KAR) are a class of signal compounds, discovered in wildfire smoke, which affect seed germination. Currently, numerous studies have focused on the model plant Arabidopsis in the KAR research field, rather than on crops. Thus the regulatory mechanisms underlying KAR regulation of crop seed germination are largely unknown. Here, we report that KAR delayed soybean seed germination through enhancing abscisic acid (ABA) biosynthesis, while impairing gibberellin (GA) biogenesis. Interest...

  9. Quantification of Abscisic Acid, Cytokinin, and Auxin Content in Salt-Stressed Plant Tissues

    Dobrev, P.; Vaňková, R. (Radomíra)

    2012-01-01

    Plant hormones cytokinins, auxin (indole-3-acetic acid), and abscisic acid are central to regulation of plant growth and defence to abiotic stresses such as salinity. Quantification of the hormone levels and determination of their ratios can reveal different plant strategies to cope with the stress, e.g., suppression of growth or mobilization of plant metabolism. This chapter describes a procedure enabling such quantification. Due to the high variability of these hormones in plant tissues, it...

  10. Exogenous abscisic acid significantly affects proteome in tea plant (Camellia sinensis) exposed to drought stress

    Lin Zhou; Hui Xu; Sue Mischke; Meinhardt, Lyndel W.; Dapeng Zhang; Xujun Zhu; Xinghui Li; Wanping Fang

    2014-01-01

    Tea [Camellia sinensis (L.) O. Kuntze] is an important economic crop, and drought is the most important abiotic stress affecting yield and quality. Abscisic acid (ABA) is an important phytohormone responsible for activating drought resistance. Increased understanding of ABA effects on tea plant under drought stress is essential to develop drought-tolerant tea genotypes, along with crop management practices that can mitigate drought stress. The objective of the present investigation is evaluat...

  11. EFFECT OF EXOGENOUS ABSCISIC ACID ON GROWTH AND BIOCHEMICAL CHANGES IN THE HALOPHYTE SUAEDA MARITIMA

    Anbarasi G.

    2015-04-01

    Full Text Available Different types of phytohormones are being extensively used to alleviate the adverse effect of salinity stress on plant growth. Among those, Abscisic acid (ABA is a plant stress hormone and one of the most important signaling molecules in plants. Drought and salinity activate De-novo abscisic acid synthesis prevent further water loss by evaporation through stomata, mediated by changes in the guard cell turgor pressure. Under osmotic stress abscisic acid induce the accumulation of protein involved in the biosynthesis of osmolites which increasing the stress tolerance of plant. In addition, exogenous application of ABA enhances the tolerance of plants or plant cells to cold, heat, drought, anoxia and heavy metal stresses. This study was carried out to study the exogenous abscisic (ABA acid induced regulatory role on the growth, water content, protein content, chlorophyll content, osmolyte accumulation and protein profiling through SDS PAGE in a halophyte, Suaeda maritima. The osmolyte accumulation of proline and glycine betaine was found to be more in 50 µM ABA concentrations. The protein profiling through SDS PAGE revealed that ̴ 66KDa proteins was not expressed in the control plant and in 10μM ABA treated plants. Interestingly, the ABA treatment induced a new protein of 14.2KDa in 10μM concentration. The ABA treated plants with concentrations 50μM, 100μM and 150μM showed changes in the expression of protein in abundance than the control and 10μM ABA treated plants. The findings in this study indicate that among all the concentrations, 50μM ABA concentration treated plants exhibited higher growth rate.

  12. Abscisic acid, gibberellins and brassinosteroids in Kelpak (R), a commercial seaweed extract made from Ecklonia maxima

    Stirk, W. A.; Tarkowská, Danuše; Turečková, Veronika; Strnad, Miroslav; van Staden, J.

    2014-01-01

    Roč. 26, č. 1 (2014), s. 561-567. ISSN 0921-8971 R&D Projects: GA MŠk LK21306; GA ČR GA206/09/1284; GA MŠk(CZ) LO1204 Grant ostatní: GA MŠk(CZ) ED0007/01/01 Institutional support: RVO:61389030 Keywords : Abscisic acid * Agricultural biostimulant * Brassinosteroids Subject RIV: EF - Botanics Impact factor: 2.559, year: 2014

  13. Quantification of Abscisic Acid, Cytokinin, and Auxin Content in Salt-Stressed Plant Tissues

    Dobrev, Petre; Vaňková, Radomíra

    Vol. 913. New York: Humana Press, 2012 - (Shabala, S.; Cuin, T.), s. 251-261. (Methods in Molecular Biology). ISBN 978-1-61779-985-3 R&D Projects: GA MŠk(CZ) LD11073 Institutional research plan: CEZ:AV0Z50380511 Keywords : Abscisic acid * Auxin * Cytokinin Subject RIV: ED - Physiology http://home.ueb.cas.cz/publikace/2012_Dobrev.pdf

  14. Sugar and abscisic acid signaling orthologs are activated at the onset of ripening in grape

    Gambetta, Gregory A.; Matthews, Mark A.; Shaghasi, Tarana H.; McElrone, Andrew J.; Castellarin, Simone D.

    2010-01-01

    The onset of ripening involves changes in sugar metabolism, softening, and color development. Most understanding of this process arises from work in climacteric fruits where the control of ripening is predominately by ethylene. However, many fruits such as grape are nonclimacteric, where the onset of ripening results from the integration of multiple hormone signals including sugars and abscisic acid (ABA). In this study, we identified ten orthologous gene families in Vitis vinifera containing...

  15. Induction of phytic acid synthesis by abscisic acid in suspension-cultured cells of rice

    Matsuno, Koya; Fujimura, Tatsuhito

    2014-01-01

    A pathway of phytic acid (PA) synthesis in plants has been revealed via investigations of low phytic acid mutants. However, the regulation of this pathway is not well understood because it is difficult to control the environments of cells in the seeds, where PA is mainly synthesized. We modified a rice suspension culture system in order to study the regulation of PA synthesis. Rice cells cultured with abscisic acid (ABA) accumulate PA at higher levels than cells cultured without ABA, and PA a...

  16. Abscisic acid is not necessary for gravitropism in primary roots of Zea mays

    Moore, R.

    1990-01-01

    Primary roots of Zea mays L. cv. Tx 5855 treated with fluridone are strongly graviresponsive, but have undetectable levels of abscisic acid (ABA). Primary roots of the carotenoid-deficient w-3, vp-5, and vp-7 mutants of Z. mays are also graviresponsive despite having undetectable amounts of ABA. Graviresponsive roots of untreated and wild-type seedlings contain 286 to 317 ng ABA g-1 f. wt, respectively. These results indicate that ABA is not necessary for root gravicurvature.

  17. Immunoaffinity chromatography of abscisic acid combined with electrospray liquid chromatography–mass spectrometry

    Hradecká, Veronika; Novák, Ondřej; Havlíček, Libor; Strnad, Miroslav

    2007-01-01

    Roč. 847, č. 2 (2007), s. 162-173. ISSN 1570-0232 R&D Projects: GA MŠk(CZ) LC06034; GA AV ČR IBS5038351 Institutional research plan: CEZ:AV0Z50380511 Source of funding: V - iné verejné zdroje ; V - iné verejné zdroje Keywords : abscisic acid * immunoaffinity chromatography * liquid chromatography-mass spectrometry Subject RIV: ED - Physiology Impact factor: 2.935, year: 2007

  18. Effect of drought and abscisic acid application on the osmotic adjustment of four wheat cultivars

    The accumulation of osmolytes in leaf tissues and the abscisic acid-induced stomatal closure are well-recognized mechanisms associated with drought tolerance in crop plants. We determine the response in terms of osmotic potential and the contents of leaf proline, glycine betaine and soluble sugar at booting and grain filling stages of four wheat (Triticum aestivum L.) cultivars to drought and exogenously applied abscisic acid (ABA) in a pot study. Leaf sample were collected 3, 6 and 9 days after drought induction and at 48 and 72 h of re-watering (recovery). Marked decreases in osmotic potential associated with the accumulation of proline, glycine betaine and soluble sugars occurred under conditions of drought stress Accession 011320 was most sensitive to drought and showed the largest decrease in osmotic potential and least accumulation of proline, sugar and glycine betaine The inhibitory effects of drought stress were ameliorated by exogenous application of ABA. This ameliorating effect was more pronounced at the booting than at grain filling stage particularly in the sensitive accession 011320. Upon rewatering the recovery from drought stress was found to be greater in case of abscisic acid application. The leaf praline content is seen to be a suitable indicator for selecting drought-tolerant genotypes. (author)

  19. Relationships of abscised cotton fruit to boll weevil (Coleoptera: Curculionidae) feeding, oviposition, and development.

    Showler, Allan T

    2008-02-01

    Abscised cotton, Gossypium hirsutum L., fruit in field plots planted at different times were examined to assess adult boll weevil, Anthonomus grandis grandis Boheman (Coleoptera: Curculionidae), use of squares and bolls during 2002 and 2003 in the Lower Rio Grande Valley of Texas. Although boll abscission is not necessarily related to infestation, generally more bolls abscised than squares and abundances of fallen bolls were not related to the planting date treatments. During 2003, fallen squares were most abundant in the late-planted treatment. Although large squares (5.5-8-mm-diameter) on the plant are preferred for boll weevil oviposition, diameter of abscised squares is not a reliable measurement because of shrinkage resulting from desiccation and larval feeding. Fallen feeding-punctured squares and bolls were most abundant in late plantings but differences between fallen feeding-punctured squares versus fallen feeding-punctured bolls were found in only one treatment in 2003. During the same year, fallen oviposition-punctured squares were more numerous in the late-planted treatment than in the earlier treatments. Treatment effects were not found on numbers of oviposition-punctured bolls, but fallen oviposition-punctured squares were more common than bolls in the late-planted treatment compared with earlier treatments each year. Dead weevil eggs, larvae, and pupae inside fallen fruit were few and planting date treatment effects were not detected. Living third instars and pupae were more abundant in fallen squares of the late-planted treatment than in the earlier treatments and bolls of all three treatments. This study shows that fallen squares in late-planted cotton contribute more to adult boll weevil populations than bolls, or squares of earlier plantings. PMID:18330118

  20. Nitric oxide functions in both methyl jasmonate signaling and abscisic acid signaling in Arabidopsis guard cells

    Saito, Naoki; Nakamura, Yoshimasa; Mori, Izumi C.; Murata, Yoshiyuki

    2009-01-01

    Intracellular components in methyl jasmonate (MeJA) signaling remain largely unknown, to compare those in well-understood abscisic acid (ABA) signaling. We have reported that nitric oxide (NO) is a signaling component in MeJA-induced stomatal closure, as well as ABA-induced stomatal closure in the previous study. To gain further information about the role of NO in the guard cell signaling, NO production was examined in an ABA- and MeJA-insensitive Arabidopsis mutant, rcn1. Neither MeJA nor AB...

  1. ATAF1 transcription factor directly regulates abscisic acid biosynthetic gene NCED3 in Arabidopsis thaliana

    Jensen, Michael Krogh; Lindemose, Søren; De Masi, Federico;

    2013-01-01

    ATAF1, an Arabidopsis thaliana NAC transcription factor, plays important roles in plant adaptation to environmental stress and development. To search for ATAF1 target genes, we used protein binding microarrays and chromatin-immunoprecipitation (ChIP). This identified T[A,C,G]CGT[A,G] and TT...... key abscisic acid (ABA) phytohormone biosynthetic gene NCED3. ChIP-qPCR and expression analysis showed that ATAF1 binding to the NCED3 promoter correlated with increased NCED3 expression and ABA hormone levels. These results indicate that ATAF1 regulates ABA biosynthesis....

  2. Abscisic acid content and stomatal sensitivity to CO/sub 2/ in leaves of Xanthium strumarium L. after pretreatments in warm and cold growth chambers

    Raschke, K.; Pierce, M.; Popiela, C.C.

    1976-01-01

    The degree of stomatal sensitivity to CO/sub 2/ was positively correlated with the content of abscisic acid of leaves of Xanthium strumarium grown in a greenhouse and then transferred for 24 hours or more to a cold (5/10 C, night/day) or a warm growth chamber (20/23 C). This correlation did not exist in plants kept in the greenhouse continuously (high abscisic acid, no CO/sub 2/ sensitivity), nor in plants transferred from the cold to the warm chamber (low absicisic acid, high CO/sub 2/ sensitivity). The abscisic acid content of leaves was correlated with water content only within narrow limits, if at all. At equal water contents, prechilled leaves contained more abscisic acid than leaves of plants pretreated in the warm chamber. There appear to be at least two compartments for abscisic acid in the leaf.

  3. Insight into 2α-Chloro-2′(2′,6′)-(Di)Halogenopicropodophyllotoxins Reacting with Carboxylic Acids Mediated by BF3·Et2O

    Lingling Fan; Xiaoyan Zhi; Zhiping Che; Hui Xu

    2015-01-01

    Stereospecific nucleophilic substitution at the C-4α position of 2α-chloro-2′(2′,6′)-(di)halogenopicropodophyllotoxin derivatives with carboxylic acids mediated by BF3·Et2O was described. Interestingly, this stereoselective products were completely controlled by the reaction time. That is, if the reaction time was prolonged to 24.5–31 h, the resulting compounds were all transformed into the unusual C-ring aromatization products. Additionally, it demonstrated that BF3·Et2O and reaction tempera...

  4. Large-scale proteome analysis of abscisic acid and ABSCISIC ACID INSENSITIVE3-dependent proteins related to desiccation tolerance in Physcomitrella patens.

    Yotsui, Izumi; Serada, Satoshi; Naka, Tetsuji; Saruhashi, Masashi; Taji, Teruaki; Hayashi, Takahisa; Quatrano, Ralph S; Sakata, Yoichi

    2016-03-18

    Desiccation tolerance is an ancestral feature of land plants and is still retained in non-vascular plants such as bryophytes and some vascular plants. However, except for seeds and spores, this trait is absent in vegetative tissues of vascular plants. Although many studies have focused on understanding the molecular basis underlying desiccation tolerance using transcriptome and proteome approaches, the critical molecular differences between desiccation tolerant plants and non-desiccation plants are still not clear. The moss Physcomitrella patens cannot survive rapid desiccation under laboratory conditions, but if cells of the protonemata are treated by the phytohormone abscisic acid (ABA) prior to desiccation, it can survive 24 h exposure to desiccation and regrow after rehydration. The desiccation tolerance induced by ABA (AiDT) is specific to this hormone, but also depends on a plant transcription factor ABSCISIC ACID INSENSITIVE3 (ABI3). Here we report the comparative proteomic analysis of AiDT between wild type and ABI3 deleted mutant (Δabi3) of P. patens using iTRAQ (Isobaric Tags for Relative and Absolute Quantification). From a total of 1980 unique proteins that we identified, only 16 proteins are significantly altered in Δabi3 compared to wild type after desiccation following ABA treatment. Among this group, three of the four proteins that were severely affected in Δabi3 tissue were Arabidopsis orthologous genes, which were expressed in maturing seeds under the regulation of ABI3. These included a Group 1 late embryogenesis abundant (LEA) protein, a short-chain dehydrogenase, and a desiccation-related protein. Our results suggest that at least three of these proteins expressed in desiccation tolerant cells of both Arabidopsis and the moss are very likely to play important roles in acquisition of desiccation tolerance in land plants. Furthermore, our results suggest that the regulatory machinery of ABA- and ABI3-mediated gene expression for desiccation

  5. Ammonium regulates embryogenic potential in Cucurbita pepo through pH-mediated changes in endogenous auxin and abscisic acid

    Pěnčík, Aleš; Turečková, Veronika; Paulisić, S.; Rolčík, Jakub; Strnad, Miroslav; Mihaljević, S.

    2015-01-01

    Roč. 122, č. 1 (2015), s. 89-100. ISSN 0167-6857 Grant ostatní: GA MŠk(CZ) ED0007/01/01 Institutional support: RVO:61389030 Keywords : Abscisic acid * Ammonium * Indole-3-acetic acid Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.125, year: 2014

  6. The p450 monooxygenase BcABA1 is essential for abscisic acid biosynthesis in Botrytis cinerea

    Siewers, V.; Smedsgaard, Jørn; Tudzynski, P.

    2004-01-01

    The phytopathogenic ascomycete Botrytis cinerea is known to produce abscisic acid (ABA), which is thought to be involved in host-pathogen interaction. Biochemical analyses had previously shown that, in contrast to higher plants, the fungal ABA biosynthesis probably does not proceed via carotenoids...

  7. Effect of exogenous abscisic acid on stomatal characteristics during acclimation of in vitro-grown tobacco (Nicotiana tabacum L.) plants

    Tichá, I.; Pospíšilová, Jana

    2008-01-01

    Roč. 133, - (2008), P09-131. ISSN 0031-9317 R&D Projects: GA ČR GA522/07/0227 Institutional research plan: CEZ:AV0Z50380511 Keywords : fluorescence * abscisic acid * antioxidative enzymes Subject RIV: ED - Physiology Impact factor: 2.334, year: 2008

  8. The antagonistic regulation of abscisic acid-inhibited root growth by brassinosteroids is partially mediated via direct suppression of ABSCISIC ACID INSENSITIVE 5 expression by BRASSINAZOLE RESISTANT 1.

    Yang, Xiaorui; Bai, Yang; Shang, Jianxiu; Xin, Ruijiao; Tang, Wenqiang

    2016-09-01

    Brassinosteroids (BRs) and abscisic acid (ABA) are plant hormones that antagonistically regulate many aspects of plant growth and development; however, the mechanisms that regulate the crosstalk of these two hormones are still not well understood. BRs regulate plant growth and development by activating BRASSINAZOLE RESISTANT 1 (BZR1) family transcription factors. Here we show that the crosstalk between BRs and ABA signalling is partially mediated by BZR1 regulated gene expression. bzr1-1D is a dominant mutant with enhanced BR signalling; our results showed that bzr1-1D mutant is less sensitive to ABA-inhibited primary root growth. By RNA sequencing, a subset of BZR1 regulated ABA-responsive root genes were identified. Of these genes, the expression of a major ABA signalling component ABA INSENSITIVE 5 (ABI5) was found to be suppressed by BR and by BZR1. Additional evidences showed that BZR1 could bind strongly with several G-box cis-elements in the promoter of ABI5, suppress the expression of ABI5 and make plants less sensitive to ABA. Our study demonstrated that ABI5 is a direct target gene of BZR1, and modulating the expression of ABI5 by BZR1 plays important roles in regulating the crosstalk between the BR and ABA signalling pathways. PMID:27149247

  9. The Abscisic Acid Levels of Wheat (Triticum aestivum L. cv. Çakmak 79) Seeds that were Germinated under Heavy Metal(Hg++,Cd++,Cu++)Stress

    MUNZUROĞLU, Ömer; KIRBAĞ ZENGİN, Fikriye; YAHYAGİL, Zübeyde

    2010-01-01

    The purpose of this study was to investigate the level of endogenous abscisic acid of wheat seeds germinated in the presence of 60, 90 and 120 ppm of mercury, cadmium and copper salt solutions for 16 hours in order to see their effects on the germination. The levels of abscisic acid were analysed by High Performance Liquid Chromatography (HPLC). The results indicated that abscisic acid levels were affected by the kind and level of heavy metals used in the experiments. The effects of these tox...

  10. The PTI1-like kinase ZmPti1a from maize (Zea mays L. co-localizes with callose at the plasma membrane of pollen and facilitates a competitive advantage to the male gametophyte

    Wienand Udo

    2006-10-01

    Full Text Available Abstract Background The tomato kinase Pto confers resistance to bacterial speck disease caused by Pseudomonas syringae pv. tomato in a gene for gene manner. Upon recognition of specific avirulence factors the Pto kinase activates multiple signal transduction pathways culminating in induction of pathogen defense. The soluble cytoplasmic serine/threonine kinase Pti1 is one target of Pto phosphorylation and is involved in the hypersensitive response (HR reaction. However, a clear role of Pti1 in plant pathogen resistance is uncertain. So far, no Pti1 homologues from monocotyledonous species have been studied. Results Here we report the identification and molecular analysis of four Pti1-like kinases from maize (ZmPti1a, -b, -c, -d. These kinase genes showed tissue-specific expression and their corresponding proteins were targeted to different cellular compartments. Sequence similarity, expression pattern and cellular localization of ZmPti1b suggested that this gene is a putative orthologue of Pti1 from tomato. In contrast, ZmPti1a was specifically expressed in pollen and sequestered to the plasma membrane, evidently owing to N-terminal modification by myristoylation and/or S-acylation. The ZmPti1a:GFP fusion protein was not evenly distributed at the pollen plasma membrane but accumulated as an annulus-like structure which co-localized with callose (1,3-β-glucan deposition. In addition, co-localization of ZmPti1a and callose was observed during stages of pollen mitosis I and pollen tube germination. Maize plants in which ZmPti1a expression was silenced by RNA interference (RNAi produced pollen with decreased competitive ability. Hence, our data provide evidence that ZmPti1a plays an important part in a signalling pathway that accelerates pollen performance and male fitness. Conclusion ZmPti1a from maize is involved in pollen-specific processes during the progamic phase of reproduction, probably in crucial signalling processes associated with regions

  11. Subthreshold receptive fields and baseline excitability of "silent" S1 callosal neurons in awake rabbits: contributions of AMPA/kainate and NMDA receptors.

    Swadlow, H A; Hicks, T P

    1997-07-01

    The contribution of NMDA and non-NMDA receptors to excitatory subthreshold receptive fields was examined in callosal efferent neurons (CC neurons) in primary somatosensory cortex of the fully awake rabbit. Only neurons showing no traditional (suprathreshold) receptive fields were examined. Subthreshold responses were examined by monitoring the thresholds of efferent neurons to juxtasomal current pulses (JSCPs) delivered through the recording microelectrode. Changes in threshold following a peripheral conditioning stimulus signify a subthreshold response. Using this method, excitatory postsynaptic potentials and inhibitory postsynaptic potentials are manifested as decreases and increases in JSCP threshold, respectively. NMDA and non-NMDA agonists and antagonists were administered iontophoretically via a multibarrel micropipette assembly attached to the recording/stimulating microelectrode. Receptor-selective doses of both AMPA/kainate and NMDA antagonists decreased the excitability of CC neurons in the absence of any peripheral stimulation. Threshold to JSCPs rose by a mean of 20% for both classes of antagonist. Despite the similar effects of NMDA and non-NMDA antagonists on baseline excitability, these antagonists had dramatically different effects on the subthreshold excitatory response to activation of the receptive field. Whereas receptor-selective doses of AMPA/kainate antagonists either eliminated or severely attenuated the subthreshold excitatory responses to peripheral stimulation, NMDA antagonists had little or no effect on the subthreshold evoked response. PMID:9262195

  12. Severe form of radiculo - myelo - neuropathy with meningo - encephalitis secondary to Angiostrongylus cantonensis infection: unusual corpus callosal lesions and serial magnetic resonance imaging findings.

    Nalini, Atchayaram; Ramakrishna, Anil; Dekumoy, Paron; Kumar, Raju Ravi; Pakdee, Wallop; Saini, Jitender; Hegde, Vinay S

    2013-01-01

    A 43-year-old man presented with the symptoms of recurrent lower abdominal pain, malaise and loss of appetite of 3-week duration, followed by acute onset of generalized paresthesias, fever and headache which progressed over few days to quadriparesis, altered sensorium, urinary and fecal incontinence. He had consumed raw tongue, liver, gall bladder and testicles of monitor lizard (Varanus bengalensis). Blood picture showed eosinophilia and cerebrospinal fluid (CSF) analysis revealed elevated protein and eosinophilia. Serum and CSF serology was positive for angiostrongyliasis. Magnetic resonance imaging showed focal hyperintense lesions in the corpus callosum and brainstem and an enhancing lesion in the cerebellum. Post-contrast T1-weighted axial images of spine showed evidence of cervical cord hyperintense lesions and root enhancement. Susceptibility weighted images/phase images showed unusual feature of multiple hemorrhagic lesions in the posterior fossa and supratentorial areas. Diffusion showed no restriction of corpus callosal lesions. Patient was treated with the high dose parenteral steroids with albendazole and at 6-month follow-up and had a remarkable recovery. PMID:24005735

  13. [Case of callosal disconnection syndrome with a chief complaint of right-hand disability, despite presence of left-hand diagonistic dyspraxia].

    Okamoto, Yoko; Saida, Hisako; Yamamoto, Toru

    2009-04-01

    e report the case of 48-year-old right-handed male patient with an infarction affecting most part of the body and the splenium of the left half of the corpus callosum. Neuropsychological examination revealed typical signs of callosal disconnection including left-sided apraxia, diagonistic dyspraxia, left-sided agraphia, left-hand tactile anomia, left hemialexia, and right-sided constructional disability. Moreover, he complained of impairment in activities involving the right hand disability and agraphia. He could not stop behaving with his right hand when he had a vague idea. For example, he involuntarily picked up a tea bottle with his right hand when he had a desire to drink, although the action was not appropriate to that occasion. The imitation and utilization behavior did not imply this case, because his right hand behaviors were not exaggerated in response to external stimuli, such as the gestures of the examiner or the subjects in front of the patient. Unexpectedly, he complained about impairment of the activity of his right hand and was unaware of left hand apraxia or diagonistic dyspraxia; this trend continued for 6 months, at the time of this writing. We argue that the patient may have been subconsciouly aware of the symptoms of his left hand but had not verbalized them. PMID:19378819

  14. Exogenous abscisic acid application during grain filling in winter wheat improves cold tolerance of offspring's seedlings

    Li, X.; Cai, J.; Liu, Fulai;

    2014-01-01

    Low temperature seriously depresses seed germination and seedling growth in winter wheat (Triticum aestivum L.). In this study, wheat plants were sprayed with abscisic acid (ABA) and fluridone (inhibitor of ABA biosynthesis) at 19 days after anthesis (DAA) and repeated at 26 DAA. The seeds of those...... plants were harvested, and seed germination and offspring's seedling growth under low temperature were evaluated. The results showed that exogenous ABA application decreased seed weight and slightly reduced seed set and seed number per spike. Under low temperature, seeds from ABA-treated plants showed...... reduced germination rate, germination index, growth of radicle and coleoptile, amylase activity and depressed starch degradation as compared with seeds from non-ABA-treated plants; however, activities of the antioxidant enzymes in both germinating seeds and seedling were enhanced from those exposed to...

  15. Isolation and Crystal Structure of 1′,4′-Trans-diol of Abscisic Acid

    WANG Tian-Shan; ZHOU Jin-Yan; TAN Hong

    2006-01-01

    1 ′,4′-Trans-diol of abscisic acid was isolated from botrytis cinerea as a colorless crystal. The molecular and crystal structures have been determined by X-ray diffraction analysis. It crystallizes in orthorhombic system, space group P212121 with a = 6.724(3), b = 17.559(6), c =12.265(2) (A), a = β = y = 90°, V = 1448.1(8) (A)3, Z = 4, Dx = 1.222 g/cm3, F(000) = 576 and μ(MoKa) = 0.087 mm-1. The final R = 0.0628 and wR = 0.1604 for 2501 independent reflections with Rint = 0.0160 and 1679 observed reflections with I >2σ(Ⅰ). There are three intermolecular hydrogen bonds in a unit cell.

  16. Effect of abscisic acid and blue radiation on photosynthesis and growth of pea plants

    The effect of abscisic acid (ABA) on the net photosynthetic rate (PN), the ribulose 1,5-bisphosphate carboxylase (RuBPC) and the phosphoenolpyruvate carboxylase (PEPC) activities, the chlorophyll (Chl) content and growth of pea plants (Pisum sativum) grown under ''white'' (WR) or blue radiation (BR), were investigated. BR as compared to WR enhanced PN, the activities of examined enzymes, and Chl content. In spite of higher PN of the plants grown under BR, dry matter of their shoots was lower in comparison with WR. ABA-treated plants grown under both WR and BR showed reduction in PN. ABA had no effect on the activities of both RuBPC and PEPC and the Chl content. Independent on the radiation quality, ABA reduced stem elongation, but did not affect the biomass of whole shoots

  17. A central role of abscisic acid in stress-regulated carbohydrate metabolism.

    Stefan Kempa

    Full Text Available BACKGROUND: Abiotic stresses adversely affect plant growth and development. The hormone abscisic acid (ABA plays a central role in the response and adaptation to environmental constraints. However, apart from the well established role of ABA in regulating gene expression programmes, little is known about its function in plant stress metabolism. PRINCIPAL FINDINGS: Using an integrative multiparallel approach of metabolome and transcriptome analyses, we studied the dynamic response of the model glyophyte Arabidopsis thaliana to ABA and high salt conditions. Our work shows that salt stress induces complex re-adjustment of carbohydrate metabolism and that ABA triggers the initial steps of carbon mobilisation. SIGNIFICANCE: These findings open new perspectives on how high salinity and ABA impact on central carbohydrate metabolism and highlight the power of iterative combinatorial approaches of non-targeted and hypothesis-driven experiments in stress biology.

  18. Possible role for abscisic acid in regulation of photosynthetic and photorespiratory carbon metabolism in barley leaves

    The influence of abscisic acid (ABA) on carbon metabolism, rate of photorespiration, and the activity of the photorespiratory enzymes ribulose bisphosphate oxygenase and glycolate oxidase in 7-day-old barley seedlings (Hordeum vulgare L. var. Alfa) was investigated. Plants treated with ABA had enhanced incorporation of labeled carbon from 14CO2 into glycolic acid, glycine, and serine, while 14C incorporation into 3-phosphoglyceric acid and sugarphosphate esters was depressed. Parallel with this effect, treated plants showed a rise in activity of RuBP oxygenase and glycolic acid oxidase. The rate of photorespiration was increased twofold by ABA treatment at IO-6 molar while the CO2-compensation point increased 46% and stomatal resistance increased more than twofold over control plants

  19. Abscisic acid-cytokinin antagonism modulates resistance against pseudomonas syringae in Tobacco

    Grosskinsky, Dominik Kilian; van der Graaff, Eric; Roitsch, Thomas Georg

    2014-01-01

    Phytohormones are known as essential regulators of plant defenses, with ethylene, jasmonic acid, and salicylic acid as the central immunity backbone, while other phytohormones have been demonstrated to interact with this. Only recently, a function of the classic phytohormone cytokinin in plant...... immunity has been described in Arabidopsis, rice, and tobacco. Although interactions of cytokinins with salicylic acid and auxin have been indicated, the complete network of cytokinin interactions with other immunity-relevant phytohormones is not yet understood. Therefore, we studied the interaction...... of kinetin and abscisic acid as a negative regulator of plant immunity to modulate resistance in tobacco against Pseudomonas syringae. By analyzing infection symptoms, pathogen proliferation, and accumulation of the phytoalexin scopoletin as a key mediator of kinetin-induced resistance in tobacco...

  20. Involvement of Polyamine Oxidase in Abscisic Acid induced Cytosolic Antioxidant Defense in Leaves of Maize

    Beibei Xue; Aying Zhang; Mingyi Jiang

    2009-01-01

    Using pharmacological and biochemical approaches, the role of maize polyamine oxidase (MPAO) in abscisic acid (ABA)induced antioxidant defense in leaves of maize (Zea mays L.) plants was investigated. Exogenous ABA treatment enhanced the expression of the MPAO gene and the activities of apoplastic MPAO. Pretreatment with two different inhibitors for apoplastic MPAO partly reduced hydrogen peroxide (H2O2) accumulation induced by ABA and blocked the ABA-induced expression of the antioxidant genes superoxide dismutase 4 and cytosolic ascorbate peroxidase and the activities of the cytosolic antioxidant enzymes. Treatment with spermidine, the optimum substrate of MPAO, also induced the expression and the activities of the antioxidant enzymes, and the upregulation of the antioxidant enzymes was prevented by two inhibitors of MPAO and two scavengers of H2O2. These results suggest that MPAO contributes to ABA-induced cytosolic antioxidant defense through H2O2, a Spd catabolic product.

  1. Movement of abscisic acid into the apoplast in response to water stress in Xanthium strumarium L

    Cornish, K.; Zeevaart, J.A.D.

    1985-07-01

    The effect of water stress on the redistribution of abscisic acid (ABA) in mature leaves of Xanthium strumarium L. was investigated using a pressure dehydration technique. In both turgid and stressed leaves, the ABA in the xylem exudate, the apoplastic ABA, increased before bulk leaf stress-induced ABA accumulation began. In the initially turgid leaves, the ABA level remained constant in both the apoplast and the leaf as a whole until wilting symptoms appeared. Following turgor loss, sufficient quantities of ABA moved into the apoplast to stimulate stomatal closure. Thus, the initial increase of apoplastic ABA may be relevant to the rapid stomatal closure seen in stressed leaves before their bulk leaf ABA levels rise. Following recovery from water stress, elevated levels of ABA remained in the apoplast after the bulk leaf contents had returned to their prestress values. This apoplastic ABA may retard stomatal reopening during the initial recovery period. 32 references, 5 figures.

  2. Abscisic acid as a factor in regulation of photosynthetic carbon metabolism of pea seedlings

    Maria Faltynowicz

    2014-02-01

    Full Text Available The influence of abscisic acid (ABA on carbon metabolism and the activity of ribulosebisphosphate (RuBP and phosphoenolpyruvate (PEP carboxylases in 8-day-old pea seedlings was investigated. It was endeavoured to correlate the changes observed in metabolic processes with the endogenous ABA level. In plants treated with ABA incorporation of labeled carbon into sucrose, glucose, fructose and sugar phosphates was depressed, while 14C incorporation into starch, ribulose and malic acid was enhanced. The activity of RuBP carboxylase was considerably lowered, whereas that of PEP carboxylase was slightly increased. It is considered that inhibition of photosynthesis due to the action of ABA is caused to a great extent by the obstruction of the C-3 pathway and reduced activity of RuBP carboxylase, whereas (β-carboxylation was not blocked.

  3. Functional annotation of the transcriptome of Sorghum bicolor in response to osmotic stress and abscisic acid

    Kumari Sunita

    2011-10-01

    Full Text Available Abstract Background Higher plants exhibit remarkable phenotypic plasticity allowing them to adapt to an extensive range of environmental conditions. Sorghum is a cereal crop that exhibits exceptional tolerance to adverse conditions, in particular, water-limiting environments. This study utilized next generation sequencing (NGS technology to examine the transcriptome of sorghum plants challenged with osmotic stress and exogenous abscisic acid (ABA in order to elucidate genes and gene networks that contribute to sorghum's tolerance to water-limiting environments with a long-term aim of developing strategies to improve plant productivity under drought. Results RNA-Seq results revealed transcriptional activity of 28,335 unique genes from sorghum root and shoot tissues subjected to polyethylene glycol (PEG-induced osmotic stress or exogenous ABA. Differential gene expression analyses in response to osmotic stress and ABA revealed a strong interplay among various metabolic pathways including abscisic acid and 13-lipoxygenase, salicylic acid, jasmonic acid, and plant defense pathways. Transcription factor analysis indicated that groups of genes may be co-regulated by similar regulatory sequences to which the expressed transcription factors bind. We successfully exploited the data presented here in conjunction with published transcriptome analyses for rice, maize, and Arabidopsis to discover more than 50 differentially expressed, drought-responsive gene orthologs for which no function had been previously ascribed. Conclusions The present study provides an initial assemblage of sorghum genes and gene networks regulated by osmotic stress and hormonal treatment. We are providing an RNA-Seq data set and an initial collection of transcription factors, which offer a preliminary look into the cascade of global gene expression patterns that arise in a drought tolerant crop subjected to abiotic stress. These resources will allow scientists to query gene

  4. Proline and Abscisic Acid Content in Droughted Corn Plant Inoculated with Azospirillum sp. and Arbuscular Mycorrhizae Fungi

    NOVRI YOULA KANDOWANGKO

    2009-03-01

    Full Text Available Plants that undergo drought stress perform a physiological response such as accumulation of proline in the leaves and increased content abscisic acid. A research was conducted to study proline and abscisic acid (ABA content on drought-stressed corn plant with Azospirillum sp. and arbuscular mycorrhizae fungi (AMF inoculated at inceptisol soil from Bogor, West Java. The experiments were carried out in a green house from June up to September 2003, using a factorial randomized block design. In pot experiments, two factors were assigned, i.e. inoculation with Azospirillum (0, 0.50, 1.00, 1.50 ml/pot and inoculation with AMF Glomus manihotis (0, 12.50, 25.00, 37.50 g/pot. The plants were observed during tasseling up to seed filling periods. Results of experiments showed that the interaction between Azospirillum sp. and AMF was synergistically increased proline, however it decreased ABA.

  5. Effects of Abscisic Acid, Gibberellin, Ethylene and Their Interactions on Production of Phenolic Acids in Salvia miltiorrhiza Bunge Hairy Roots

    Liang, Zongsuo; Ma, Yini; Xu, Tao; Cui, Beimi; Liu, Yan; Guo, Zhixin; Yang, Dongfeng

    2013-01-01

    Salvia miltiorrhiza is one of the most important traditional Chinese medicinal plants because of its excellent performance in treating coronary heart disease. Phenolic acids mainly including caffeic acid, rosmarinic acid and salvianolic acid B are a group of active ingredients in S. miltiorrhiza. Abscisic acid (ABA), gibberellin (GA) and ethylene are three important phytohormones. In this study, effects of the three phytohormones and their interactions on phenolic production in S. miltiorrhiz...

  6. Ascorbic acid and reactive oxygen species are involved in the inhibition of seed germination by abscisic acid in rice seeds

    Ye, Nenghui; Zhu, Guohui; Liu, Yinggao; Zhang, Aying; Li, Yingxuan; Liu, Rui; Shi, Lu; Jia, Liguo; Zhang, Jianhua

    2011-01-01

    The antagonism between abscisic acid (ABA) and gibberellin (GA) plays a key role in controlling seed germination, but the mechanism of antagonism during this process is not known. The possible links among ABA, reactive oxygen species (ROS), ascorbic acid (ASC), and GA during rice seed germination were investigated. Unlike in non-seed tissues where ROS production is increased by ABA, ABA reduced ROS production in imbibed rice seeds, especially in the embryo region. Such reduced ROS also led to...

  7. Antagonism between abscisic acid and gibberellins is partially mediated by ascorbic acid during seed germination in rice

    Ye, Nenghui; Zhang, Jianhua

    2012-01-01

    The antagonism between abscisic acid (ABA) and gibberellin (GA) plays a key role in controlling seed germination,1,2 but the mechanism of antagonism during this process is not known. In the associated study,3 we investigated the relationship among ABA, reactive oxygen species (ROS), ascorbic acid (ASC) and GA during rice seed germination. ROS production is reduced by ABA, which hence results in decreasing ASC accumulation during imbibition. GA accumulation was also suppressed by a reduced ROS...

  8. Cytokinin, auxin, and abscisic acid dynamics during flower development in white and red currants infected with Blackcurrant reversion virus

    Gaudinová, Alena; Malbeck, Jiří; Dobrev, Petre; Kubelková, Darina; Špak, Josef; Vaňková, Radomíra

    2009-01-01

    Roč. 73, č. 6 (2009), s. 119-125. ISSN 0885-5765 R&D Projects: GA MŠk 1P05OC052; GA MŠk OC09084 Institutional research plan: CEZ:AV0Z50380511; CEZ:AV0Z50510513 Keywords : Full blossom disease * Cytokinin * Auxin * Abscisic acid Subject RIV: ED - Physiology Impact factor: 1.407, year: 2009

  9. Gibberellin-to-abscisic acid balances govern development and differentiation of the nucellar projection of barley grains

    Weier, D.; Thiel, J.; Kohl, S.; Tarkowská, Danuše; Strnad, Miroslav; Schaarschmidt, S.; Weschke, W.; Weber, H.; Hause, B.

    2014-01-01

    Roč. 65, č. 18 (2014), s. 5291-5304. ISSN 0022-0957 R&D Projects: GA MŠk LK21306 Grant ostatní: GA MŠk(CZ) ED0007/01/01 Institutional support: RVO:61389030 Keywords : Assimilate transfer * barley endosperm * gibberellin-to-abscisic acid balances Subject RIV: EF - Botanics Impact factor: 5.526, year: 2014

  10. Jasmonate signaling involves the abscisic acid receptor PYL4 to regulate metabolic reprogramming in Arabidopsis and tobacco

    Lackman, P.; Gonzalez-Guzman, M.; Tilleman, S.; Carqueijeiro, I.; Perez, A.C.; Moses, T.; Seo, M.; Kanno, Y; Hakkinen, S. T.; Van Montagu, M. C. E.; Thevelein, J M; Maaheimo, H.; Oksman-Caldentey, K.-M.; Rodriguez, P L; Rischer, H.

    2011-01-01

    The phytohormones jasmonates (JAs) constitute an important class of elicitors for many plant secondary metabolic pathways. However, JAs do not act independently but operate in complex networks with crosstalk to several other phytohormonal signaling pathways. Here, crosstalk was detected between the JA and abscisic acid (ABA) signaling pathways in the regulation of tobacco (Nicotiana tabacum) alkaloid biosynthesis. A tobacco gene from the PYR/PYL/RCAR family, NtPYL4, the expression of which is...

  11. Foliar abscisic acid-to-ethylene accumulation and response regulate shoot growth sensitivity to mild drought in wheat

    Valluru, Ravi; Davies, William John; Reynolds, Matthew; Dodd, Ian Charles

    2016-01-01

    Although, plant hormones play an important role in adjusting growth in response to environmental perturbation, the relative contributions of abscisic acid (ABA) and ethylene remain elusive. Using six spring wheat genotypes differing for stress tolerance, we show that young seedlings of the drought-tolerant (DT) group maintained or increased shoot dry weight (SDW) while the drought-susceptible (DS) group decreased SDW in response to mild drought. Both the DT and DS groups increased endogenous ...

  12. Foliar abscisic acid-to-ethylene accumulation and response regulate shoot growth sensitivity to mild drought in wheat

    Ravi eValluru; William J eDavies; Matthew P eReynolds; Ian C eDodd

    2016-01-01

    Although plant hormones play an important role in adjusting growth in response to environmental perturbation, the relative contributions of abscisic acid (ABA) and ethylene remain elusive. Using six spring wheat genotypes differing for stress tolerance, we show that young seedlings of the drought-tolerant (DT) group maintained or increased shoot dry weight (SDW) while the drought-susceptible (DS) group decreased SDW in response to mild drought. Both the DT and DS groups increased endogenous A...

  13. Gene Overexpression and RNA Silencing Tools for the Genetic Manipulation of the S-(+)-Abscisic Acid Producing Ascomycete Botrytis cinerea

    Zhong-Tao Ding; Zhi Zhang; Di Luo; Jin-Yan Zhou; Juan Zhong; Jie Yang; Liang Xiao; Dan Shu; Hong Tan

    2015-01-01

    The phytopathogenic ascomycete Botrytis cinerea produces several secondary metabolites that have biotechnical significance and has been particularly used for S-(+)-abscisic acid production at the industrial scale. To manipulate the expression levels of specific secondary metabolite biosynthetic genes of B. cinerea with Agrobacterium tumefaciens-mediated transformation system, two expression vectors (pCBh1 and pCBg1 with different selection markers) and one RNA silencing vector, pCBSilent1, w...

  14. Functional annotation of the transcriptome of Sorghum bicolor in response to osmotic stress and abscisic acid

    Kumari Sunita; Klein Robert R; Olsen Andrew; Monaco Marcela K; Dugas Diana V; Ware Doreen; Klein Patricia E

    2011-01-01

    Abstract Background Higher plants exhibit remarkable phenotypic plasticity allowing them to adapt to an extensive range of environmental conditions. Sorghum is a cereal crop that exhibits exceptional tolerance to adverse conditions, in particular, water-limiting environments. This study utilized next generation sequencing (NGS) technology to examine the transcriptome of sorghum plants challenged with osmotic stress and exogenous abscisic acid (ABA) in order to elucidate genes and gene network...

  15. Abscisic acid enhances tolerance of wheat seedlings to drought and regulates transcript levels of genes encoding ascorbate-glutathione biosynthesis

    Wei, Liting; Wang, Lina; Yang, Yang; Wang, Pengfei; Guo, Tiancai; Kang, Guozhang

    2015-01-01

    Glutathione (GSH) and ascorbate (ASA) are associated with the abscisic acid (ABA)-induced abiotic tolerance in higher plant, however, its molecular mechanism remains obscure. In this study, exogenous application (10 μM) of ABA significantly increased the tolerance of seedlings of common wheat (Triticum aestivum L.) suffering from 5 days of 15% polyethylene glycol (PEG)-stimulated drought stress, as demonstrated by increased shoot lengths and shoot and root dry weights, while showing decreased...

  16. Crystallization and preliminary X-ray diffraction studies of the abscisic acid receptor PYL3 and its complex with pyrabactin

    Crystals of the abscisic acid receptor PYL3 and of the PYL3–pyrabactin complex were obtained and optimized in order to obtain high-quality diffraction data. Diffraction data sets were collected and processed to 2.5 and 1.83 Å resolution, respectively. Abscisic acid (ABA) modulates many developmental processes and responses to environmental stress. Recently, a family of pyrabactin resistance-like proteins (PYLs) in Arabidopsis thaliana were identified to be abscisic acid receptors. Although the 14 PYLs members share a similar sequence identity, they exhibit different responses toward pyrabactin. Apo-PYL3 is a dimer; however, its oligomeric state changes greatly on the addition of pyrabactin. Moreover, pyrabactin binds dimeric PYL3 in a nonproductive mode which prevents receptor activation and inhibition of PP2Cs. Here, the expression, purification and crystallization of apo-PYL3 and of PYL3 complexed with pyrabactin are reported. Diffraction data were optimized to 2.5 Å resolution for apo-PYL3 and to 1.83 Å resolution for PYL3–pyrabactin. The crystals of apo-PYL3 and PYL3–pyrabactin belonged to space groups P41212 and P212121, respectively

  17. Exogenous application of abscisic acid may improve the growth and yield of sunflower hybrids under drought

    Sunflower genotypes perform differently under different water regimes. Drought stress at various growth stages drastically reduces the growth, development and yield of sunflower hybrids. However, exogenous application of abscisic acid helps in mitigating drought stress by improving growth, development and yield of sunflower. In the present study, three sunflower hybrids viz. DK-4040 (large stature), S-278 (medium stature) and SF-187 (short stature) were exposed to varied irrigation regimes and abscisic acid application schedule i.e. T1: four irrigations with schedule (25DAS, at bud, flower initiation and at achene formation) and with no ABA spray,T/sub 2/: three irrigations with schedule (25DAS, at flower initiation and at achene formation) and with no ABA spray, T/sub 3/: three irrigations with schedule (25DAS, at flower initiation and at achene formation) and with 8 mu MABA spray at bud initiation, T/sub 4/: three irrigations with schedule (25DAS, at bud initiation and at achene formation) and with no ABA spray, T/sub 5/: three irrigations with schedule (25DAS, at bud initiation and at achene formation) and with 8 mu M ABA spray at flower initiation. Experiment was laid out in Randomized Complete Design with factorial arrangement having three replications. ABA application at bud or at flower initiation under drought stress helped in mitigating the detrimental effects by improving growth and yield of sunflower hybrids. Enhancement in drought tolerance of sunflower genotypes was better when ABA was applied at bud initiation stage than that of at flower initiation stage under drought. Improvements in head diameter, achenes per head, 1000-achene weight, achene yield, oil yield, biological yield, harvest index, leaf area index and crop growth rate was recorded. Sunflower hybrid DK-4040 showed more improvement in drought tolerance byfoliar application of ABA under water deficit stress than that of the SF-187 and S-278. It is suggested that sunflower hybrid DK 4040

  18. Role of abscisic acid (aba) in modulating the responses of two apple rootstocks to drought stress

    Drought stress is considered as the main limiting factor for apple (Malus domestica L.) production in some semi-arid areas of China. In this study, we investigated the modulation role of abscisic acid (ABA) and fluridone (ABA synthesis inhibitor) on water relations and antioxidant enzyme system in 2-year-old seedlings of two apple rootstocks i.e. Malus sieversii (Ledeb.) Roem. (MS) and Malus hupehensis (Pamp.) Rehd. (MH). Drought stress induced ion leakage, accumulation of malondiadehyde (MDA) and decreases in leaf water potential and relative water content (RWC) in both rootstocks, which were significantly alleviated by exogenous ABA application. Drought stress also induced markedly increases in endogenous ABA content and activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), ascorbate peroxidase (APX), dehydroascorbate reductase (DHAR), monodehydroascorbate reductase (MDHAR), and glutathione reductase (GR), to a greater magnitude in MS as compared to MH rootstock. Concentration of 100 mol/L and 50 mol/L ABA had the most positive effects on drought-stressed rootstocks of MS and MH, respectively. Spraying optimum exogenous ABA contributed to enhancement in most of the above antioxidant enzymes activities but reduction in content of MDA and maintained the appropriate leaf water potential and RWC in both rootstocks. Pretreatment with fluridone aggravated ion leakage and the accumulation of MDA in two apple rootstocks under drought stress, which was overcome by exogenous ABA application to some extent. In conclusion, the endogenous ABA was probably involved in the regulation of two apple rootstocks in responses to drought stress. (author)

  19. Transcriptomic insights into antagonistic effects of gibberellin and abscisic acid on petal growth in Gerbera hybrida.

    Li, Lingfei; Zhang, Wenbin; Zhang, Lili; Li, Na; Peng, Jianzong; Wang, Yaqin; Zhong, Chunmei; Yang, Yuping; Sun, Shulan; Liang, Shan; Wang, Xiaojing

    2015-01-01

    Petal growth is central to floral morphogenesis, but the underlying genetic basis of petal growth regulation is yet to be elucidated. In this study, we found that the basal region of the ray floret petals of Gerbera hybrida was the most sensitive to treatment with the phytohormones gibberellin (GA) and abscisic acid (ABA), which regulate cell expansion during petal growth in an antagonistic manner. To screen for differentially expressed genes (DEGs) and key regulators with potentially important roles in petal growth regulation by GA or/and ABA, the RNA-seq technique was employed. Differences in global transcription in petals were observed in response to GA and ABA and target genes antagonistically regulated by the two hormones were identified. Moreover, we also identified the pathways associated with the regulation of petal growth after application of either GA or ABA. Genes relating to the antagonistic GA and ABA regulation of petal growth showed distinct patterns, with genes encoding transcription factors (TFs) being active during the early stage (2 h) of treatment, while genes from the "apoptosis" and "cell wall organization" categories were expressed at later stages (12 h). In summary, we present the first study of global expression patterns of hormone-regulated transcripts in G. hybrida petals; this dataset will be instrumental in revealing the genetic networks that govern petal morphogenesis and provides a new theoretical basis and novel gene resources for ornamental plant breeding. PMID:25852718

  20. A gate-latch-lock mechanism for hormone signalling by abscisic acid receptors

    Melcher, Karsten; Ng, Ley-Moy; Zhou, X Edward; Soon, Fen-Fen; Xu, Yong; Suino-Powell, Kelly M; Park, Sang-Youl; Weiner, Joshua J; Fujii, Hiroaki; Chinnusamy, Viswanathan; Kovach, Amanda; Li, Jun; Wang, Yonghong; Li, Jiayang; Peterson, Francis C; Jensen, Davin R; Yong, Eu-Leong; Volkman, Brian F; Cutler, Sean R; Zhu, Jian-Kang; Xu, H Eric; (NU Sinapore); (Van Andel); (MCW); (UCR); (Chinese Aca. Sci.)

    2010-01-12

    Abscisic acid (ABA) is a ubiquitous hormone that regulates plant growth, development and responses to environmental stresses. Its action is mediated by the PYR/PYL/RCAR family of START proteins, but it remains unclear how these receptors bind ABA and, in turn, how hormone binding leads to inhibition of the downstream type 2C protein phosphatase (PP2C) effectors. Here we report crystal structures of apo and ABA-bound receptors as well as a ternary PYL2-ABA-PP2C complex. The apo receptors contain an open ligand-binding pocket flanked by a gate that closes in response to ABA by way of conformational changes in two highly conserved β-loops that serve as a gate and latch. Moreover, ABA-induced closure of the gate creates a surface that enables the receptor to dock into and competitively inhibit the PP2C active site. A conserved tryptophan in the PP2C inserts directly between the gate and latch, which functions to further lock the receptor in a closed conformation. Together, our results identify a conserved gate-latch-lock mechanism underlying ABA signalling.

  1. Proanthocyanidins Inhibit Seed Germination by Maintaining a High Level of Abscisic Acid in Arabidopsis thaliana

    Liguo Jia; Jianhua Zhang; Qiuyu Wu; Nenghui Ye; Rui Liu; Lu Shi; Weifeng Xu; Hui Zhi; A. N. M. Rubaiyath Bin Rahman; Yiji Xia

    2012-01-01

    Proanthocyanidins (PAs) are the main products of the flavonoid biosynthetic pathway in seeds,but their biological function during seed germination is still unclear.We observed that seed germination is delayed with the increase of exogenous PA concentration in Arabidopsis.A similar inhibitory effect occurred in peeled Brassica napus seeds,which was observed by measuring radicle elongation.Using abscisic acid (ABA),a biosynthetic and metabolic inhibitor,and gene expression analysis by real-time polymerase chain reaction,we found that the inhibitory effect of PAs on seed germination is due to their promotion of ABA via de novo biogenesis,rather than by any inhibition of its degradation.Consistent with the relationship between PA content and ABA accumulation in seeds,PA-deficient mutants maintain a lower level of ABA compared with wild-types during germination.Our data suggest that PA distribution in the seed coat can act as a doorkeeper to seed germination.PA regulation of seed germination is mediated by the ABA signaling pathway.

  2. Hydrogen peroxide modulates abscisic acid signaling in root growth and development in Arabidopsis

    BAI Ling; ZHOU Yun; ZHANG XiaoRan; SONG ChunPeng; Gao MingQing

    2007-01-01

    Exogenous abscisic acid (ABA) can inhibit root growth and promote formation of more root hairs in the root tip of Arabidopsis. However, the molecular mechanisms that underlie root ABA signaling are largely unknown. We report here that hydrogen peroxide (H2O2) reduces the root growth of wild type,and the phenotype of H2O2 on the root growth is similar to ABA response. Meanwhile ABA-induced changes in the morphology of root system can be partly reversed by ascorbic acid in wild type and abolished in NADPH oxidase defective mutant atrbohF and atrbohC. Further, ABA can induce H2O2 accumulation in the root cells and enhance transcription level of OXI1, which is necessary for many more AOS-dependent processes such as root hair growth in Arabidopsis. Our results suggest that H2O2 as an important signal molecule is required for the ABA-regulated root growth and development in Arabidopsis.

  3. UV-induced cross-linking of abscisic acid to binding proteins

    Conditions for UV-induced cross-linking of abscisic acid (ABA) through its enone chromophore to binding proteins were evaluated. The effects of a UV-light band between 260 and 530 nm on both unconjugated and protein-conjugated ABA, as well as on anti-ABA antibodies as models of ABA-binding proteins were determined. UV irradiation caused both isomerization and photolysis of ABA, but increasing the lower irradiation boundary to 345 nm strongly reduced photolysis and largely prevented isomerization. When conjugated to alkaline phosphatase (AP), ABA remained stable when using either a 320 or a 345 nm filter. At these wavelengths both binding of ABA to antibodies as well as AP enzymatic activity were maintained. UV-induced cross-linking of monoclonal anti-ABA antibodies to immobilized ABA was analysed by immunoassays. Optimal cross-linking was achieved after a 5 min irradiation period at 0°, using a long pass, cut-on filter to quench wavelengths below 290 nm. This cross-linking faithfully reflected cognate binding activity. (author)

  4. K-channels inhibited by hydrogen peroxide mediate abscisic acid signaling in Vicia guard cells

    2001-01-01

    A number of studies show that environmental stress conditions increase abscisic acid (ABA) and hydrogen peroxide (H2O2) levels in plant cells. Despite this central role of ABA in altering stomatal aperture by regulating guard cell ion transport, little is known concerning the relationship between ABA and H2O2 in signal transduction leading to stomatal movement. Epidermal strip bioassay illustrated that ABA-inhibited stomatal opening and ABA-induced stomatal closure were abolished partly by externally added catalase (CAT) or diphenylene iodonium (DPI), which are a H2O2 scavenger and a NADPH oxidase inhibitor respectively. In contrast, internally added CAT or DPI nearly completely or partly reversed ABA-induced closure in half-stoma. Consistent with these results, whole-cell patch-clamp analysis showed that intracellular application of CAT or DPI partly abolished ABA-inhibited inward K+ current across the plasma membrane of guard cells. H2O2 mimicked ABA to inhibit inward K+ current, an effect which was reversed by the addition of ascorbic acid (Vc) in patch clamping micropipettes. These results suggested that H2O2 mediated ABA-induced stomatal movement by targeting inward K+ channels at plasma membrane.

  5. Relative quantification of phosphoproteomic changes in grapevine (Vitis vinifera L.) leaves in response to abscisic acid

    Rattanakan, Supakan; George, Iniga; Haynes, Paul A; Cramer, Grant R

    2016-01-01

    In a previous transcriptomic analysis, abscisic acid (ABA) was found to affect the abundance of a number of transcripts in leaves of Cabernet Sauvignon grapevines with roots that had been exposed to 10 μm ABA for 2 h. Other work has indicated that ABA affects protein abundance and protein phosphorylation as well. In this study we investigated changes in protein abundance and phosphorylation of Cabernet Sauvignon grapevine leaves. Protein abundance was assessed by both label-free and isobaric-label quantitive proteomic methods. Each identified common proteins, but also additional proteins not found with the other method. Overall, several thousand proteins were identified and several hundred were quantified. In addition, hundreds of phosphoproteins were identified. Tens of proteins were found to be affected in the leaf after the roots had been exposed to ABA for 2 h, more than half of them were phosphorylated proteins. Many phosphosites were confirmed and several new ones were identified. ABA increased the abundance of some proteins, but the majority of the proteins had their protein abundance decreased. Many of these proteins were involved in growth and plant organ development, including proteins involved in protein synthesis, photosynthesis, sugar and amino-acid metabolism. This study provides new insights into how ABA regulates plant responses and acclimation to water deficits. PMID:27366326

  6. The Dynamics of Embolism Refilling in Abscisic Acid (ABA-Deficient Tomato Plants

    Francesca Secchi

    2012-12-01

    Full Text Available Plants are in danger of embolism formation in xylem vessels when the balance between water transport capacity and transpirational demand is compromised. To maintain this delicate balance, plants must regulate the rate of transpiration and, if necessary, restore water transport in embolized vessels. Abscisic acid (ABA is the dominant long-distance signal responsible for plant response to stress, and it is possible that it plays a role in the embolism/refilling cycle. To test this idea, a temporal analysis of embolism and refilling dynamics, transpiration rate and starch content was performed on ABA-deficient mutant tomato plants. ABA-deficient mutants were more vulnerable to embolism formation than wild-type plants, and application of exogenous ABA had no effect on vulnerability. However, mutant plants treated with exogenous ABA had lower stomatal conductance and reduced starch content in the xylem parenchyma cells. The lower starch content could have an indirect effect on the plant’s refilling activity. The results confirm that plants with high starch content (moderately stressed mutant plants were more likely to recover from loss of water transport capacity than plants with low starch content (mutant plants with application of exogenous ABA or plants experiencing severe water stress. This study demonstrates that ABA most likely does not play any direct role in embolism refilling, but through the modulation of carbohydrate content, it could influence the plant’s capacity for refilling.

  7. Phenolic compounds in juice of “Isabel” grape treated with abscisic acid for color improvement

    Yamamoto Lilian Yukari

    2015-01-01

    Full Text Available Isabel grape is the main cultivar used to produce juice in Brazil, which has rusticity and high productivity, but it is deficient in anthocyanins, a pigment responsible for the color. Thus, an alternative is the application of abscisic acid (S-ABA, which is responsible to promote the synthesis of anthocyanins. The aim of this work was to evaluate the phenolic compounds composition in “Isabel” grape juice treated with S-ABA, by HPLC-DAD–ESI-MS/MS technique. The results showed the increasing in total anthocyanin concentration in juices, with S-ABA treatments, as well as the proportion of B-ring tri-substituted anthocyanidins. Regarding total flavonols, differences were only significant in juices obtained in 2012 season. S-ABA treatments did not significantly affect the hydroxycinnamic acid derivatives, flavan-3-ols, resveratrol and antioxidant capacity of juices. Juice from “Isabel” grapes treated with S-ABA provides an enhancement of total anthocyanin concentration, mainly when grapes are treated before or at the onset of véraison.

  8. An Abscisic Acid-Independent Oxylipin Pathway Controls Stomatal Closure and Immune Defense in Arabidopsis

    Mondy, Samuel; Tranchimand, Sylvain; Rumeau, Dominique; Boudsocq, Marie; Garcia, Ana Victoria; Douki, Thierry; Bigeard, Jean; Laurière, Christiane; Chevalier, Anne; Castresana, Carmen; Hirt, Heribert

    2013-01-01

    Plant stomata function in innate immunity against bacterial invasion and abscisic acid (ABA) has been suggested to regulate this process. Using genetic, biochemical, and pharmacological approaches, we demonstrate that (i) the Arabidopsis thaliana nine-specific-lipoxygenase encoding gene, LOX1, which is expressed in guard cells, is required to trigger stomatal closure in response to both bacteria and the pathogen-associated molecular pattern flagellin peptide flg22; (ii) LOX1 participates in stomatal defense; (iii) polyunsaturated fatty acids, the LOX substrates, trigger stomatal closure; (iv) the LOX products, fatty acid hydroperoxides, or reactive electrophile oxylipins induce stomatal closure; and (v) the flg22-mediated stomatal closure is conveyed by both LOX1 and the mitogen-activated protein kinases MPK3 and MPK6 and involves salicylic acid whereas the ABA-induced process depends on the protein kinases OST1, MPK9, or MPK12. Finally, we show that the oxylipin and the ABA pathways converge at the level of the anion channel SLAC1 to regulate stomatal closure. Collectively, our results demonstrate that early biotic signaling in guard cells is an ABA-independent process revealing a novel function of LOX1-dependent stomatal pathway in plant immunity. PMID:23526882

  9. Supplementation with Abscisic Acid Reduces Malaria Disease Severity and Parasite Transmission.

    Glennon, Elizabeth K K; Adams, L Garry; Hicks, Derrick R; Dehesh, Katayoon; Luckhart, Shirley

    2016-06-01

    Nearly half of the world's population is at risk for malaria. Increasing drug resistance has intensified the need for novel therapeutics, including treatments with intrinsic transmission-blocking properties. In this study, we demonstrate that the isoprenoid abscisic acid (ABA) modulates signaling in the mammalian host to reduce parasitemia and the formation of transmissible gametocytes and in the mosquito host to reduce parasite infection. Oral ABA supplementation in a mouse model of malaria was well tolerated and led to reduced pathology and enhanced gene expression in the liver and spleen consistent with infection recovery. Oral ABA supplementation also increased mouse plasma ABA to levels that can signal in the mosquito midgut upon blood ingestion. Accordingly, we showed that supplementation of a Plasmodium falciparum-infected blood meal with ABA increased expression of mosquito nitric oxide synthase and reduced infection prevalence in a nitric oxide-dependent manner. Identification of the mechanisms whereby ABA reduces parasite growth in mammals and mosquitoes could shed light on the balance of immunity and metabolism across eukaryotes and provide a strong foundation for clinical translation. PMID:27001761

  10. Microarray Analysis of Transcriptional Responses to Abscisic Acid and Salt Stress in Arabidopsis thaliana

    Yucheng Wang

    2013-05-01

    Full Text Available Abscisic acid (ABA plays a crucial role in plant responses to abiotic stress. To investigate differences in plant responses to salt and ABA stimulus, differences in gene expression in Arabidopsis in response to salt and ABA were compared using an Agilent oligo microarray. A total of 144 and 139 genes were significantly up- and downregulated, respectively, under NaCl stress, while 406 and 381 genes were significantly up- and downregulated, respectively, under ABA stress conditions. In addition, 31 genes were upregulated by both NaCl and ABA stresses, and 23 genes were downregulated by these stressors, suggesting that these genes may play similar roles in plant responses to salt and ABA stress. Gene ontology (GO analysis revealed four subgroups of genes, including genes in the GO categories “Molecular transducer activity”, “Growth”, “Biological adhesion” and “Pigmentation”, which were expressed in response to ABA stress but not NaCl stress. In addition, genes that play specific roles during salt or ABA stress were identified. Our results may help elucidate differences in the response of plants to salt and ABA stress.

  11. Production of Polyamines Is Enhanced by Endogenous Abscisic Acid in Maize Seedlings Subjected to Salt Stress

    Jun LIU; Ming-Yi JIANG; Yi-Feng ZHOU; You-Liang LIU

    2005-01-01

    It is known that salt stress and exogenously applied abscisic acid (ABA) can enhance the polyamine content in plants and that salt stress itself can lead to an increase in endogenous ABA production.In the present study, the relationships between salt-induced ABA and polyamine accumulation were investigated using ABA-deficient mutant (vp5/vp5) maize (Zea mays L.) seedlings and ABA and polyamine :biosynthesis inhibitors. The results show that reduced endogenous ABA levels, as a result of either the mutation or by using a chemical inhibitor (sodium tungstate), also reduced the accumulation of polyamines in salt-stressed leaves of maize seedlings. The polyamine synthesis inhibitors D-arginine and αdifluoromethylornithine also reduced the polyamine content of the leaves of maize seedling under salt stress. Both ABA and polyamine enhanced the dry weight accumulation of salt-stressed seedlings and also increased the activities of the two dominant tonoplast membrane enzymes, H+-ATPase and H+-PPase, when plants were under salt stress. The results suggest that salt stress induces an increase in endogenous ABA levels, which then enhances polyamine synthesis. Such responses may increase a plant's tolerance to salt.

  12. A gate-latch-lock mechanism for hormone signalling by abscisic acid receptors

    Melcher, Karsten

    2009-12-03

    Abscisic acid (ABA) is a ubiquitous hormone that regulates plant growth, development and responses to environmental stresses. Its action is mediated by the PYR/PYL/RCAR family of START proteins, but it remains unclear how these receptors bind ABA and, in turn, how hormone binding leads to inhibition of the downstream type 2C protein phosphatase (PP2C) effectors. Here we report crystal structures of apo and ABA-bound receptors as well as a ternary PYL2-ABA-PP2C complex. The apo receptors contain an open ligand-binding pocket flanked by a gate that closes in response to ABA by way of conformational changes in two highly conserved ?-loops that serve as a gate and latch. Moreover, ABA-induced closure of the gate creates a surface that enables the receptor to dock into and competitively inhibit the PP2C active site. A conserved tryptophan in the PP2C inserts directly between the gate and latch, which functions to further lock the receptor in a closed conformation. Together, our results identify a conserved gate-latch-lock mechanism underlying ABA signalling. © 2009 Macmillan Publishers Limited. All rights reserved.

  13. Salicylic acid antagonizes abscisic acid inhibition of shoot growth and cell cycle progression in rice

    Meguro, Ayano; Sato, Yutaka

    2014-04-01

    We analysed effects of abscisic acid (ABA, a negative regulatory hormone), alone and in combination with positive or neutral hormones, including salicylic acid (SA), on rice growth and expression of cell cycle-related genes. ABA significantly inhibited shoot growth and induced expression of OsKRP4, OsKRP5, and OsKRP6. A yeast two-hybrid assay showed that OsKRP4, OsKRP5, and OsKRP6 interacted with OsCDKA;1 and/or OsCDKA;2. When SA was simultaneously supplied with ABA, the antagonistic effect of SA completely blocked ABA inhibition. SA also blocked ABA inhibition of DNA replication and thymidine incorporation in the shoot apical meristem. These results suggest that ABA arrests cell cycle progression by inducing expression of OsKRP4, OsKRP5, and OsKRP6, which inhibit the G1/S transition, and that SA antagonizes ABA by blocking expression of OsKRP genes.

  14. Ubiquitin-specific protease 24 negatively regulates abscisic acid signalling in Arabidopsis thaliana.

    Zhao, Jinfeng; Zhou, Huapeng; Zhang, Ming; Gao, Yanan; Li, Long; Gao, Ying; Li, Ming; Yang, Yuhong; Guo, Yan; Li, Xueyong

    2016-02-01

    Abscisic acid (ABA) is an important plant hormone integrating environmental stress and plant growth. Protein ubiquitination and deubiquitination are reversible processes catalysed by E3 ubiquitin ligase and deubiquitinating enzyme, respectively. Lots of E3 ubiquitin ligase and transcriptional factors modified by ubiquitination were reported to modulate ABA signalling. However, no deubiquitinating enzyme has been identified that functions in ABA signalling until now. Here, we isolated an ABA overly sensitive mutant, ubp24, in which the gene encoding ubiquitin-specific protease 24 (UBP24, At4g30890) was disrupted by a T-DNA insertion. The ubp24 mutant was hypersensitive to ABA and salt stress in both post-germinative growth and seedling growth. However, stomata closure in the ubp24 mutant was less sensitive to ABA, and the ubp24 mutant showed drought sensitivity. UBP24 possessed deubiquitinating enzyme activity, and the activity was essential for UBP24 function. Additionally, UBP24 formed homodimer in vivo. UBP24 was genetically upstream of ABI2, and the phosphatase activity of protein phosphatase 2C was decreased in the ubp24 mutant compared with the wild type in the presence of ABA. These results uncover an important regulatory role for the ubiquitin-specific protease in response to ABA and salt stress in plant. PMID:26290265

  15. Reactive oxygen species, abscisic acid and ethylene interact to regulate sunflower seed germination.

    El-Maarouf-Bouteau, Hayat; Sajjad, Yasar; Bazin, Jérémie; Langlade, Nicolas; Cristescu, Simona M; Balzergue, Sandrine; Baudouin, Emmanuel; Bailly, Christophe

    2015-02-01

    Sunflower (Helianthus annuus L.) seed dormancy is regulated by reactive oxygen species (ROS) and can be alleviated by incubating dormant embryos in the presence of methylviologen (MV), a ROS-generating compound. Ethylene alleviates sunflower seed dormancy whereas abscisic acid (ABA) represses germination. The purposes of this study were to identify the molecular basis of ROS effect on seed germination and to investigate their possible relationship with hormone signalling pathways. Ethylene treatment provoked ROS generation in embryonic axis whereas ABA had no effect on their production. The beneficial effect of ethylene on germination was lowered in the presence of antioxidant compounds, and MV suppressed the inhibitory effect of ABA. MV treatment did not alter significantly ethylene nor ABA production during seed imbibition. Microarray analysis showed that MV treatment triggered differential expression of 120 probe sets (59 more abundant and 61 less abundant genes), and most of the identified transcripts were related to cell signalling components. Many transcripts less represented in MV-treated seeds were involved in ABA signalling, thus suggesting an interaction between ROS and ABA signalling pathways at the transcriptional level. Altogether, these results shed new light on the crosstalk between ROS and plant hormones in seed germination. PMID:24811898

  16. Stomatal response to abscisic Acid is a function of current plant water status.

    Tardieu, F; Davies, W J

    1992-02-01

    We investigated, under laboratory and field conditions, the possibility that increasing abscisic acid (ABA) concentrations and decreasing water potentials can interact in their effects on stomata. One experiment was carried out with epidermal pieces of Commelina communis incubated in media with a variety of ABA and polyethylene glycol concentrations. In the media without ABA, incubation in solutions with water potentials between -0.3 and -1.5 megapascals had no significant effect on stomatal aperture. Conversely, the sensitivity of stomatal aperture to ABA was trebled in solutions at -1.5 megapascals compared with sensitivity at -0.3 megapascals. The effect of the change in sensitivity was more important than the absolute effect of ABA at the highest water potential. In a field experiment, sensitivity of maize stomatal conductance to the concentration of ABA in the xylem sap varied strongly with the time of the day. We consider that the most likely explanation for this is the influence of a change in leaf or epidermal water potential that accompanies an increase in irradiance and saturation deficit as the day progresses. These observations suggest that epidermal water relations may act as a modulator of the responses of stomata to ABA. We argue that such changes must be taken into account in studies or modeling of plant responses to drought stress. PMID:16668674

  17. Abscisic Acid Control of rbcS and cab Transcription in Tomato Leaves.

    Bartholomew, D M; Bartley, G E; Scolnik, P A

    1991-05-01

    Leaves of tomato (Lycopersicon esculentum) plants grown in soil in which moisture was lowered from field capacity to levels approaching permanent wilting point show a 10-fold increase in abscisic acid (ABA) and a 60 to 70 percent decrease in rbcS and cab steady-state mRNA levels. As indicated by transcription run-on experiments, the effect occurs primarily at the transcriptional level. Similar water deficit had only a minor effect on ABA level and on rbcS and cab expression in leaves of sitiens, an ABA mutant of tomato. Expression of rbcL, the chloroplast gene coding for the large subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase, is not affected by water stress. Application of exogenous ABA results in decreased rbcS and cab expression in both wild-type and sitiens leaves. Analysis of the expression of individual members of the rbcS gene family indicates that under water-deficit conditions, expression derives primarily from only three of the five rbcS genes. Effects of dark adaptation and water deficit are additive for cab but not for rbcS expression. These results support the hypothesis that, at least under water-deficit conditions, ABA or a derivative thereof mediates a negative regulation of rbcS and cab transcription in tomato plants. PMID:16668167

  18. Exogenous Abscisic Acid and Gibberellic Acid Elicit Opposing Effects on Fusarium graminearum Infection in Wheat.

    Buhrow, Leann M; Cram, Dustin; Tulpan, Dan; Foroud, Nora A; Loewen, Michele C

    2016-09-01

    Although the roles of salicylate (SA) and jasmonic acid (JA) have been well-characterized in Fusarium head blight (FHB)-infected cereals, the roles of other phytohormones remain more ambiguous. Here, the association between an array of phytohormones and FHB pathogenesis in wheat is investigated. Comprehensive profiling of endogenous hormones demonstrated altered cytokinin, gibberellic acid (GA), and JA metabolism in a FHB-resistant cultivar, whereas challenge by Fusarium graminearum increased abscisic acid (ABA), JA, and SA in both FHB-susceptible and -resistant cultivars. Subsequent investigation of ABA or GA coapplication with fungal challenge increased and decreased FHB spread, respectively. These phytohormones-induced effects may be attributed to alteration of the F. graminearum transcriptome because ABA promoted expression of early-infection genes, including hydrolases and cytoskeletal reorganization genes, while GA suppressed nitrogen metabolic gene expression. Neither ABA nor GA elicited significant effects on F. graminearum fungal growth or sporulation in axenic conditions, nor do these phytohormones affect trichothecene gene expression, deoxynivalenol mycotoxin accumulation, or SA/JA biosynthesis in F. graminearum-challenged wheat spikes. Finally, the combined application of GA and paclobutrazol, a Fusarium fungicide, provided additive effects on reducing FHB severity, highlighting the potential for combining fungicidal agents with select phytohormone-related treatments for management of FHB infection in wheat. PMID:27135677

  19. The Arabidopsis Vacuolar Sorting Receptor1 Is Required for Osmotic Stress-Induced Abscisic Acid Biosynthesis

    Wang, Zhen-Yu

    2014-11-21

    Osmotic stress activates the biosynthesis of the phytohormone abscisic acid (ABA) through a pathway that is rate limited by the carotenoid cleavage enzyme 9-cis-epoxycarotenoid dioxygenase (NCED). To understand the signal transduction mechanism underlying the activation of ABA biosynthesis, we performed a forward genetic screen to isolate mutants defective in osmotic stress regulation of the NCED3 gene. Here, we identified the Arabidopsis (Arabidopsis thaliana) Vacuolar Sorting Receptor1 (VSR1) as a unique regulator of ABA biosynthesis. The vsr1 mutant not only shows increased sensitivity to osmotic stress, but also is defective in the feedback regulation of ABA biosynthesis by ABA. Further analysis revealed that vacuolar trafficking mediated by VSR1 is required for osmotic stress-responsive ABA biosynthesis and osmotic stress tolerance. Moreover, under osmotic stress conditions, the membrane potential, calcium flux, and vacuolar pH changes in the vsr1 mutant differ from those in the wild type. Given that manipulation of the intracellular pH is sufficient to modulate the expression of ABA biosynthesis genes, including NCED3, and ABA accumulation, we propose that intracellular pH changes caused by osmotic stress may play a signaling role in regulating ABA biosynthesis and that this regulation is dependent on functional VSR1.

  20. Postharvest Exogenous Application of Abscisic Acid Reduces Internal Browning in Pineapple.

    Zhang, Qin; Liu, Yulong; He, Congcong; Zhu, Shijiang

    2015-06-10

    Internal browning (IB) is a postharvest physiological disorder causing economic losses in pineapple, but there is no effective control measure. In this study, postharvest application of 380 μM abscisic acid (ABA) reduced IB incidence by 23.4-86.3% and maintained quality in pineapple fruit. ABA reduced phenolic contents and polyphenol oxidase and phenylalanine ammonia lyase activities; increased catalase and peroxidase activities; and decreased O2(·-), H2O2, and malondialdehyde levels. This suggests ABA could control IB through inhibiting phenolics biosynthesis and oxidation and enhancing antioxidant capability. Furthermore, the efficacy of IB control by ABA was not obviously affected by tungstate, ABA biosynthesis inhibitor, nor by diphenylene iodonium, NADPH oxidase inhibitor, nor by lanthanum chloride, calcium channel blocker, suggesting that ABA is sufficient for controlling IB. This process might not involve H2O2 generation, but could involve the Ca(2+) channels activation. These results provide potential for developing effective measures for controlling IB in pineapple. PMID:26007196

  1. Interactions between ethylene, abscisic acid and cytokinin during germination and seedling establishment in Arabidopsis

    Veeraputhiran Subbiah; Karingu Janardhan Reddy

    2010-09-01

    In order to investigate the interaction of the plant hormones ethylene, abscisic acid (ABA) and cytokinin in seed germination and early seedling development, we studied germination in ethylene-related mutants of Arabidopsis. Mutations in the genes etr1 and ein2, which reduce ethylene responses, showed increased dormancy and a delay in germination in comparison with wild type. Mutations in etr1, ein2 and ein6 also resulted in increased sensitivity to ABA with respect to inhibition of germination. Conversely, mutations in ctr1 and eto3, which lead to an increased ethylene response and overproduction of ethylene, respectively, decreased sensitivity to ABA during germination. Increased ABA sensitivity was also effected in wild type seeds by the presence during germination of AgNO3, an inhibitor of ethylene action. The addition of the cytokinin N-6 benzyl adenine (BA) reversed the increased sensitivity of ethylene-resistant mutants to ABA. The action of cytokinin in reversing increased ABA sensitivity of ethylene-resistant mutants also suggests that at least part of the action of cytokinin in promoting germination is independent of its role in stimulating ethylene production. These observations further extend the evidence in support of interaction between ethylene, ABA and cytokinin signalling in controlling seed germination and early seedling development in Arabidopsis.

  2. Growth, Gas Exchange, Abscisic Acid, and Calmodulin Response to Salt Stress in Three Poplars

    2006-01-01

    In the present study, we investigated the effects of increasing salinity on growth, gas exchange, abscisic acid(ABA), calmodulin (CAM), and the relevance to salt tolerance in seedlings of Populus euphratica Oliv. and cuttings of P. "pupularis 35-44" (P. popularis) and P. x euramericana cv. 1-214 (P. cv. Italica). The relative growth rates of shoot height (RGRH) for P. cv. Italica and P. popularis were severely reduced by increasing salt stress,whereas the growth reduction was relatively less in P. euphratica. Similarly, P. euphratica maintained higher net photosynthetic rates (Pn) and unit transpiration rates (TRN) than P. cv. Italica and P. popularis under conditions of higher salinity. Salinity caused a significant increase in leaf ABA and CaM in the three genotypes after the onset of stress, but NaCl-induced ABA and CaM accumulation was more pronounced in P. euphratica,suggesting that P. euphratica plants are more sensitive in sensing soil salinity than the other two poplars.Furthermore, P. euphratica maintained relatively higher ABA and CaM concentrations under conditions of high salinity. The higher capacity to synthesize stress signals, namely ABA and CaM, in P. euphratica and the contribution of this to the salt resistance of P. euphratica are discussed.

  3. Functional analysis of a Lemna gibba rbcS promoter regulated by abscisic acid and sugar

    Youru Wang

    2013-04-01

    Photosynthesis-associated nuclear genes (PhANGs) are able to respond to multiple environmental and developmental signals, including light, sugar and abscisic acid (ABA). PhANGs have been extensively studied at the level of transcriptional regulation, and several cis-acting elements important for light responsiveness have been identified in their promoter sequences. However, the regulatory elements involved in sugar and ABA regulation of PhANGs have not been completely characterized. A ribulose-1,5-bisphosphate carboxylase small subunit gene (rbcS) promoter (SSU5C promoter) was isolated from duckweed (Lemna gibba). A series of SSU5C promoter 5′ deletion fragments were fused to an intron–gus gene, and transgenic tobacco suspension cell lines were generated. Assay of tobacco suspension cell line harbouring the complete promoter in the fusion construct indicated that SSU5C promoter was negatively regulated by sugar and ABA under the condition of regular photoperiod. 5′ deletion analysis of SSU5C promoter in transgenic tobacco suspension cell lines confirmed that a region between positions $-310$ and $-152$ included the ABA-response region, and that sugar-response cis-acting elements might be located in the region between $-152$ and $-117$. Taken together, our results confirmed that the cis-regulatory region responsible for repression by ABA and sugar in the SSU5C promoter was located between $-310$ and $-117$.

  4. Abscisic acid - an overlooked player in plant-microbe symbioses formation?

    Stec, Natalia; Banasiak, Joanna; Jasiński, Michał

    2016-01-01

    Abscisic acid (ABA) is an ubiquitous plant hormone and one of the foremost signalling molecules, controlling plants' growth and development, as well as their response to environmental stresses. To date, the function of ABA has been extensively investigated as an abiotic stress molecule which regulates the plants' water status. However, in the context of symbiotic associations, ABA is less recognized. In contrast to well-described auxin/cytokinin and gibberellin/strigolactone involvement in symbioses, ABA has long been underestimated. Interestingly, ABA emerges as an important player in arbuscular mycorrhiza and legume-rhizobium symbiosis. The plant's use of stress hormones like ABA in regulation of those interactions directly links the efficiency of these processes to the environmental status of the plant, notably during drought stress. Here we provide an overview of ABA interplay in beneficial associations of plants with microorganisms and propose ABA as a potential factor determining whether the investment in establishing the interaction is higher than the profit coming from it. PMID:26828669

  5. Insight into 2α-Chloro-2‧(2‧,6‧)-(Di)Halogenopicropodophyllotoxins Reacting with Carboxylic Acids Mediated by BF3·Et2O

    Fan, Lingling; Zhi, Xiaoyan; Che, Zhiping; Xu, Hui

    2015-11-01

    Stereospecific nucleophilic substitution at the C-4α position of 2α-chloro-2‧(2‧,6‧)-(di)halogenopicropodophyllotoxin derivatives with carboxylic acids mediated by BF3·Et2O was described. Interestingly, this stereoselective products were completely controlled by the reaction time. That is, if the reaction time was prolonged to 24.5-31 h, the resulting compounds were all transformed into the unusual C-ring aromatization products. Additionally, it demonstrated that BF3·Et2O and reaction temperature were the important factors for C-ring aromatization, and AlCl3 could be substituted for BF3·Et2O as a lewis acid for C-ring aromatization. Halogenation of E-ring of 2β-chloropodophyllotoxins with NCS or NBS also led to the same C-ring aromatization compounds. Especially compounds 5c, 6g and 7b exhibited insecticidal activity equal to that of toosendanin.

  6. Insight into 2α-Chloro-2'(2',6')-(Di)Halogenopicropodophyllotoxins Reacting with Carboxylic Acids Mediated by BF3·Et2O.

    Fan, Lingling; Zhi, Xiaoyan; Che, Zhiping; Xu, Hui

    2015-01-01

    Stereospecific nucleophilic substitution at the C-4α position of 2α-chloro-2'(2',6')-(di)halogenopicropodophyllotoxin derivatives with carboxylic acids mediated by BF3·Et2O was described. Interestingly, this stereoselective products were completely controlled by the reaction time. That is, if the reaction time was prolonged to 24.5-31 h, the resulting compounds were all transformed into the unusual C-ring aromatization products. Additionally, it demonstrated that BF3·Et2O and reaction temperature were the important factors for C-ring aromatization, and AlCl3 could be substituted for BF3·Et2O as a lewis acid for C-ring aromatization. Halogenation of E-ring of 2β-chloropodophyllotoxins with NCS or NBS also led to the same C-ring aromatization compounds. Especially compounds 5c, 6g and 7b exhibited insecticidal activity equal to that of toosendanin. PMID:26573374

  7. Abscisic Acid Induces Rapid Reductions in Mesophyll Conductance to Carbon Dioxide.

    Giuseppe Sorrentino

    Full Text Available The rate of photosynthesis (A of plants exposed to water deficit is a function of stomatal (gs and mesophyll (gm conductance determining the availability of CO2 at the site of carboxylation within the chloroplast. Mesophyll conductance often represents the greatest impediment to photosynthetic uptake of CO2, and a crucial determinant of the photosynthetic effects of drought. Abscisic acid (ABA plays a fundamental role in signalling and co-ordination of plant responses to drought; however, the effect of ABA on gm is not well-defined. Rose, cherry, olive and poplar were exposed to exogenous ABA and their leaf gas exchange parameters recorded over a four hour period. Application with ABA induced reductions in values of A, gs and gm in all four species. Reduced gm occurred within one hour of ABA treatment in three of the four analysed species; indicating that the effect of ABA on gm occurs on a shorter timescale than previously considered. These declines in gm values associated with ABA were not the result of physical changes in leaf properties due to altered turgor affecting movement of CO2, or caused by a reduction in the sub-stomatal concentration of CO2 (Ci. Increased [ABA] likely induces biochemical changes in the properties of the interface between the sub-stomatal air-space and mesophyll layer through the actions of cooporins to regulate the transport of CO2. The results of this study provide further evidence that gm is highly responsive to fluctuations in the external environment, and stress signals such as ABA induce co-ordinated modifications of both gs and gm in the regulation of photosynthesis.

  8. An Ancestral Role for CONSTITUTIVE TRIPLE RESPONSE1 Proteins in Both Ethylene and Abscisic Acid Signaling.

    Yasumura, Yuki; Pierik, Ronald; Kelly, Steven; Sakuta, Masaaki; Voesenek, Laurentius A C J; Harberd, Nicholas P

    2015-09-01

    Land plants have evolved adaptive regulatory mechanisms enabling the survival of environmental stresses associated with terrestrial life. Here, we focus on the evolution of the regulatory CONSTITUTIVE TRIPLE RESPONSE1 (CTR1) component of the ethylene signaling pathway that modulates stress-related changes in plant growth and development. First, we compare CTR1-like proteins from a bryophyte, Physcomitrella patens (representative of early divergent land plants), with those of more recently diverged lycophyte and angiosperm species (including Arabidopsis [Arabidopsis thaliana]) and identify a monophyletic CTR1 family. The fully sequenced P. patens genome encodes only a single member of this family (PpCTR1L). Next, we compare the functions of PpCTR1L with that of related angiosperm proteins. We show that, like angiosperm CTR1 proteins (e.g. AtCTR1 of Arabidopsis), PpCTR1L modulates downstream ethylene signaling via direct interaction with ethylene receptors. These functions, therefore, likely predate the divergence of the bryophytes from the land-plant lineage. However, we also show that PpCTR1L unexpectedly has dual functions and additionally modulates abscisic acid (ABA) signaling. In contrast, while AtCTR1 lacks detectable ABA signaling functions, Arabidopsis has during evolution acquired another homolog that is functionally distinct from AtCTR1. In conclusion, the roles of CTR1-related proteins appear to have functionally diversified during land-plant evolution, and angiosperm CTR1-related proteins appear to have lost an ancestral ABA signaling function. Our study provides new insights into how molecular events such as gene duplication and functional differentiation may have contributed to the adaptive evolution of regulatory mechanisms in plants. PMID:26243614

  9. Application time and concentrations of abscisic acid on the color development of ‘Isabel’ grapes

    Renata Koyama

    2014-09-01

    Full Text Available The grape ‘Isabel’ main cultivar used for juice production in Brazil has a deficiency of coloring and an alternative is the application of abscisic acid (S-ABA, since the accumulation of anthocyanins, pigment that interferes in the color of berries, appears to be regulated by this growth regulator. The aim of this research was to evaluate the effect of different concentrations of S-ABA applied at different times in the clusters of ‘Isabel’ grapes to improve their color attributes. The vines were conducted in a vertical support structure, spaced 2 x 1 m in cordon. A randomized block design was used as a statistical model, with 4 replications and 5 treatments, as follows: control; S-ABA 200 mg L-1 applied seven days after veraison (DAV; S-ABA 400 mg L-1 7 DAV; S-ABA 200 mg L-1 7 DAV +S-ABA 200 mg L-1 10 days before harvest (DBH; S-ABA 400 mg L-1 7 DAV + 400 mg L-1 10 DBH. At harvest the following variables were evaluated: mass and diameter of the berries, mass and length of the clusters; soluble solids (SS, titratable acidity (TA and maturation index (TSS/TA. It was also evaluated the concentration of anthocyanins and total polyphenol index in wine and juice, prepared by the extraction method of the pan and color of the berries by colorimetry. The application of S-ABA did not influence the physical characteristics of the grapes, however, favored the increase of SS and SS/TA of the berries, except for the concentration of 200 mg L-1 applied seven days after veraison. The S-ABA has an effect on improving the content of anthocyanins of the berries and the juice of the ‘Isabel’ grape, mainly in the 400 mg L-1 applied 7 DAV + 10 DBH, besides enabling the improvement in the color attribute of berries.

  10. Identification of Interactions between Abscisic Acid and Ribulose-1,5-Bisphosphate Carboxylase/Oxygenase.

    Marek M Galka

    Full Text Available Abscisic acid ((+-ABA is a phytohormone involved in the modulation of developmental processes and stress responses in plants. A chemical proteomics approach using an ABA mimetic probe was combined with in vitro assays, isothermal titration calorimetry (ITC, x-ray crystallography and in silico modelling to identify putative (+-ABA binding-proteins in crude extracts of Arabidopsis thaliana. Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco was identified as a putative ABA-binding protein. Radiolabelled-binding assays yielded a Kd of 47 nM for (+-ABA binding to spinach Rubisco, which was validated by ITC, and found to be similar to reported and experimentally derived values for the native ribulose-1,5-bisphosphate (RuBP substrate. Functionally, (+-ABA caused only weak inhibition of Rubisco catalytic activity (Ki of 2.1 mM, but more potent inhibition of Rubisco activation (Ki of ~ 130 μM. Comparative structural analysis of Rubisco in the presence of (+-ABA with RuBP in the active site revealed only a putative low occupancy (+-ABA binding site on the surface of the large subunit at a location distal from the active site. However, subtle distortions in electron density in the binding pocket and in silico docking support the possibility of a higher affinity (+-ABA binding site in the RuBP binding pocket. Overall we conclude that (+-ABA interacts with Rubisco. While the low occupancy (+-ABA binding site and weak non-competitive inhibition of catalysis may not be relevant, the high affinity site may allow ABA to act as a negative effector of Rubisco activation.

  11. Abscisic acid and stress signals induce Viviparous1 expression in seed and vegetative tissues of maize.

    Cao, Xueyuan; Costa, Liliana M; Biderre-Petit, Corinne; Kbhaya, Bouchab; Dey, Nrisingha; Perez, Pascual; McCarty, Donald R; Gutierrez-Marcos, Jose F; Becraft, Philip W

    2007-02-01

    Viviparous1 (Vp1) encodes a B3 domain-containing transcription factor that is a key regulator of seed maturation in maize (Zea mays). However, the mechanisms of Vp1 regulation are not well understood. To examine physiological factors that may regulate Vp1 expression, transcript levels were monitored in maturing embryos placed in culture under different conditions. Expression of Vp1 decreased after culture in hormone-free medium, but was induced by salinity or osmotic stress. Application of exogenous abscisic acid (ABA) also induced transcript levels within 1 h in a dose-dependent manner. The Vp1 promoter fused to beta-glucuronidase or green fluorescent protein reproduced the endogenous Vp1 expression patterns in transgenic maize plants and also revealed previously unknown expression domains of Vp1. The Vp1 promoter is active in the embryo and aleurone cells of developing seeds and, upon drought stress, was also found in phloem cells of vegetative tissues, including cobs, leaves, and stems. Sequence analysis of the Vp1 promoter identified a potential ABA-responsive complex, consisting of an ACGT-containing ABA response element (ABRE) and a coupling element 1-like motif. Electrophoretic mobility shift assay confirmed that the ABRE and putative coupling element 1 components specifically bound proteins in embryo nuclear protein extracts. Treatment of embryos in hormone-free Murashige and Skoog medium blocked the ABRE-protein interaction, whereas exogenous ABA or mannitol treatment restored this interaction. Our data support a model for a VP1-dependent positive feedback mechanism regulating Vp1 expression during seed maturation. PMID:17208960

  12. LTP3 contributes to disease susceptibility in Arabidopsis by enhancing abscisic acid (ABA) biosynthesis.

    Gao, Shan; Guo, Wenya; Feng, Wen; Liu, Liang; Song, Xiaorui; Chen, Jian; Hou, Wei; Zhu, Hongxia; Tang, Saijun; Hu, Jian

    2016-04-01

    Several plant lipid transfer proteins (LTPs) act positively in plant disease resistance. Here, we show that LTP3 (At5g59320), a pathogen and abscisic acid (ABA)-induced gene, negatively regulates plant immunity in Arabidopsis. The overexpression of LTP3 (LTP3-OX) led to an enhanced susceptibility to virulent bacteria and compromised resistance to avirulent bacteria. On infection of LTP3-OX plants with Pseudomonas syringae pv. tomato, genes involved in ABA biosynthesis, NCED3 and AAO3, were highly induced, whereas salicylic acid (SA)-related genes, ICS1 and PR1, were down-regulated. Accordingly, in LTP3-OX plants, we observed increased ABA levels and decreased SA levels relative to the wild-type. We also showed that the LTP3 overexpression-mediated enhanced susceptibility was partially dependent on AAO3. Interestingly, loss of function of LTP3 (ltp3-1) did not affect ABA pathways, but resulted in PR1 gene induction and elevated SA levels, suggesting that LTP3 can negatively regulate SA in an ABA-independent manner. However, a double mutant consisting of ltp3-1 and silent LTP4 (ltp3/ltp4) showed reduced susceptibility to Pseudomonas and down-regulation of ABA biosynthesis genes, suggesting that LTP3 acts in a redundant manner with its closest homologue LTP4 by modulating the ABA pathway. Taken together, our data show that LTP3 is a novel negative regulator of plant immunity which acts through the manipulation of the ABA-SA balance. PMID:26123657

  13. NFX1-LIKE2 (NFXL2 suppresses abscisic acid accumulation and stomatal closure in Arabidopsis thaliana.

    Janina Lisso

    Full Text Available The NFX1-LIKE1 (NFXL1 and NFXL2 genes were identified as regulators of salt stress responses. The NFXL1 protein is a nuclear factor that positively affects adaptation to salt stress. The nfxl1-1 loss-of-function mutant displayed reduced survival rates under salt and high light stress. In contrast, the nfxl2-1 mutant, defective in the NFXL2 gene, and NFXL2-antisense plants exhibited enhanced survival under these conditions. We show here that the loss of NFXL2 function results in abscisic acid (ABA overaccumulation, reduced stomatal conductance, and enhanced survival under drought stress. The nfxl2-1 mutant displayed reduced stomatal aperture under all conditions tested. Fusicoccin treatment, exposition to increasing light intensities, and supply of decreasing CO(2 concentrations demonstrated full opening capacity of nfxl2-1 stomata. Reduced stomatal opening presumably is a consequence of elevated ABA levels. Furthermore, seedling growth, root growth, and stomatal closure were hypersensitive to exogenous ABA. The enhanced ABA responses may contribute to the improved drought stress resistance of the mutant. Three NFXL2 splice variants were cloned and named NFXL2-78, NFXL2-97, and NFXL2-100 according to the molecular weight of the putative proteins. Translational fusions to the green fluorescent protein suggest nuclear localisation of the NFXL2 proteins. Stable expression of the NFXL2-78 splice variant in nfxl2-1 plants largely complemented the mutant phenotype. Our data show that NFXL2 controls ABA levels and suppresses ABA responses. NFXL2 may prevent unnecessary and costly stress adaptation under favourable conditions.

  14. Influence Mechanism of Endogenous Abscisic Acid on Storage Softening Process of Hardy Kiwifruit

    Li Shuqian

    2014-01-01

    Full Text Available In order to study the relation of Abscisic Acid (ABA with other biochemistry factors during hardy kiwifruit softening process. The changing trend of ABA under the fruits storage conditions of 20 and 0C was analyzed. A conclusion is drawn as below: During storage under 20C, it shows the highest content of ABA in 4 days to 222.19 &mu g/L, which reaches the almost same content in 3 and 5 days. The value keeps inclining since 5 days and decline rate is lower in 7 and 8 days. The lowest value is reached to 20.88 &mug/L in 10 days. During storage under 0C, ABA content is at a relatively high level but shows the slow down trend. ABA content falls greatly from 9 to 11 days. After this period, ABA content still follows up-trend and declining then. The peak appears in 15 days to 90.49 &mug/L, but it is lower than that in the first nine days. Moreover, peak during storage in environment under 0C is lower than that during the storage in environment at normal temperature, accordingly delaying fruit softening. As the ABA content rises to the highest level, the fruit hardness drops drastically. When ABA content slightly changes, the hardness decreases gently. ABA content is featured that same changing trend of ethylene content, respiratory intensity, pectase content and amylase content. Moreover, ABA has the same peak appearance time as amylase but it is later than appearance of both pectase and ethylene, they basically match each other. The rule of peak appearance time is not obvious for ABA and amylase. Mutual inhibition exists between peak appearance time of ABA and respiratory intensity. Quick ABA rise is accompanied with slow amylase rise and vice versa.

  15. Effects of abscisic acid and xanthoxin on elongation and gravitropism in primary roots of Zea mays

    Lee, J. S.; Hasenstein, K. H.; Mulkey, T. J.; Yang, R. L.; Evans, M. L.

    1990-01-01

    We examined the involvement of abscisic acid (ABA) and xanthoxin (Xan) in maize root gravitropism by (1) testing the ability of ABA to allow positive gravitropism in dark-grown seedlings of the maize cultivar LG11, a cultivar known to require light for positive gravitropism of the primary root, (2) comparing curvature in roots in which half of the cap had been excised and replaced with agar containing either ABA or indole-3-acetic acid (IAA), (3) measuring gravitropism in roots of seedlings submerged in oxygenated solutions of ABA or IAA and (4) testing the effect of Xan on root elongation. Using a variety of methods of applying ABA to the root, we found that ABA did not cause horizontally-oriented primary roots of dark-grown seedlings to become positively gravitropic. Replacing half of the root cap of vertically oriented roots with an agar block containing ABA had little or no effect on curvature relative to that of controls in which the half cap was replaced by a plain agar block. Replacement of the removed half cap with IAA either canceled or reversed the curvature displayed by controls. When light-grown seedlings were submerged in ABA they responded strongly to gravistimulation while those in IAA did not. Xan (up to 0.1 mM) did not affect root elongation. The results indicate that ABA is not a likely mediator of root gravitropism and that the putative ABA precursor, Xan, lacks the appropriate growth-inhibiting properties to serve as a mediator of root gravitropism.

  16. Abscisic acid metabolism in relation to water stress and leaf age in Xanthium strumarium

    Cornish, K.; Zeevaart, J.A.D.

    1984-12-01

    Intact plants of Xanthium strumarium L. were subjected to a water stress-recovery cycle. As the stress took effect, leaf growth ceased and stomatal resistance increased. The mature leaves then wilted, followed by the half expanded ones. Water, solute, and pressure potentials fell steadily in all leaves during the rest of the stress period. After 3 days, the young leaves lost turgor and the plants were rewatered. All the leaves rapidly regained turgor and the younger ones recommenced elongation. Stomatal resistance declined, but several days elapsed before pre-stress values were attained. Abscisic aid (ABA) and phaseic acid (PA) levels rose in all the leaves after the mature ones wilted. ABA-glucose ester (ABA-GE) levels increased to a lesser extent, and the young leaves contained little of this conjugate. PA leveled off in the older leaves during the last 24 hours of stress, and ABA levels declined slightly. The young leaves accumulated ABA and PA throughout the stress period and during the 14-hour period immediately following rewatering. The ABA and PA contents, expressed per unit dry weight, were highest in the young leaves. Upon rewatering, large quantities of PA appeared in the mature leaves as ABA levels fell to the pre-stress level within 14 hours. In the half expanded and young leaves, it took several days to reach pre-stress ABA values. ABA-GE synthesis ceased in the mature leaves, once the stress was relieved, but continued in the half expanded and young leaves for 2 days. Mature leaves, when detached and stressed, accumulated an amount of ABA similar to that in leaves on the intact plant. In contrast, detached and stressed young leaves produced little ABA. Studies with radioactive (+/-)-ABA indicated that in young leaves the conversion of ABA to PA took place at a much lower rate than in mature ones. 25 references, 10 figures, 2 tables.

  17. Arabidopsis cysteine-rich receptor-like kinase 45 functions in the responses to abscisic acid and abiotic stresses

    Zhang, Xiujuan

    2013-06-01

    The phytohormone abscisic acid (ABA) regulates seed germination, plant growth and development, and response to abiotic stresses such as drought and salt stresses. Receptor-like kinases are well known signaling components that mediate plant responses to developmental and environmental stimuli. Here, we characterized the biological function of an ABA and stress-inducible cysteine-rich receptor-like protein kinase, CRK45, in ABA signaling in Arabidopsis thaliana. The crk45 mutant was less sensitive to ABA than the wild type during seed germination and early seedling development, whereas CRK45 overexpression plants were more sensitive to ABA compared to the wild type. Furthermore, overexpression of CRK45 led to hypersensitivity to salt and glucose inhibition of seed germination, whereas the crk45 mutant showed the opposite phenotypes. In addition, CRK45 overexpression plants had enhanced tolerance to drought. Gene expression analyses revealed that the expression of representative stress-responsive genes was significantly enhanced in CRK45 overexpression plants in response to salt stress. ABA biosynthetic genes such as NCED3,. 22NCED3, 9-Cis-Epoxycarotenoid Dioxygenase 3.NCED5,. 33NCED5, 9-Cis-Epoxycarotenoid Dioxygenase 5.ABA2,. 44ABA2, Abscisic Acid Deficient 2. and AAO355AAO3, Abscisic Aldehyde Oxidase 3. were also constitutively elevated in the CRK45 overexpression plants. We concluded that CRK45 plays an important role in ABA signaling that regulates Arabidopsis seeds germination, early seedling development and abiotic stresses response, by positively regulating ABA responses in these processes. © 2013 Elsevier Masson SAS.

  18. Effect of abscisic acid, Paclobutrazol and Salicylic acid on the growth and Pigment variation in Solanum Trilobatum (l

    D. Nivedithadevi

    2012-09-01

    Full Text Available Solanum trilobatum (Family: Solanaceae is one of the common Indian medicinal plants and it has been used in traditional medicine for many centuries. This plant is a thorny creeper with bluish violet flower, more commonly available in southern India has been used traditional in Siddha system of medicines to treat various diseases. The roots, leaves, berries and flowers are used for cough. The decoction of entire Solanum trilobatum plant is used to treat acute and chronic bronchitis. It has been widely used to treat respiratory disorders. This plant is commonly used to treat asthma, cough, dysonoea, chronic febrile infections and difficult parturition. The constituents of this plant include sobatum, -solamarine, solanine, solasodine, glycoalkaloid, diosogenin and tomatidine. Plant growth regulators are substance that influences physiological processes of plants at very low concentration. Abscisic acid is a many important plant growth development processed. Paclobutrazol is a triazolic group of fungicide which has plant growth regulating properties. Salicylic acid is phenolic phytohormones and is formed in plants with role of plant growth and development. The given treatments were started at 70th day followed by 80th, 90th and 100th days. The groups were treated with respect growth hormones by spraying method. After 10th day, the plants were harvested for further analysis. On over all physical assessment plants treated with paclobutrazol were found to have more whole plant fresh weight, dry weight, root length and stem length followed by abscisic acid and salicylic acid. After the physical evaluation, the leaves were collected from each group for pigment analysis. Chlorophyll, carotenoid, anthocyanin and xanthophylls pigment contents were increased in abscisic acid followed by paclobutrazol and salicylic acid.

  19. H2O2 mediates the crosstalk of brassinosteroid and abscisic acid in tomato responses to heat and oxidative stresses

    Zhou, Jie; Wang, Jian; Li, Xin; Xia, Xiao-Jian; Zhou, Yan-Hong; Shi, Kai; Chen, Zhixiang; Yu, Jing-Quan

    2014-01-01

    The production of H2O2 is critical for brassinosteroid (BR)- and abscisic acid (ABA)-induced stress tolerance in plants. In this study, the relationship between BR and ABA in the induction of H2O2 production and their roles in response to heat and paraquat (PQ) oxidative stresses were studied in tomato. Both BR and ABA induced increases in RBOH1 gene expression, NADPH oxidase activity, apoplastic H2O2 accumulation, and heat and PQ stress tolerance in wild-type plants. BR could only induced tr...

  20. Altered cytokinin metabolism affects cytokinin, auxin, and abscisic acid contents in leaves and chloroplasts, and chloroplast ultrastructure in transgenic tobacco

    Polanská, Lenka; Vičánková, Anna; Nováková, Marie; Malbeck, Jiří; Dobrev, Petre; Brzobohatý, Břetislav; Vaňková, Radomíra; Macháčková, Ivana

    2007-01-01

    Roč. 58, č. 3 (2007), s. 637-649. ISSN 0022-0957 R&D Projects: GA ČR GA206/03/0369; GA ČR GA206/06/1306; GA AV ČR IAA600040612 Institutional research plan: CEZ:AV0Z50380511; CEZ:AV0Z50040507 Source of funding: V - iné verejné zdroje ; V - iné verejné zdroje Keywords : abscisic acid * auxin * chloroplast ultrastructure Subject RIV: EF - Botanics Impact factor: 3.917, year: 2007

  1. Acid-Mediated N-H/α,β-C(sp(3))-H Trifunctionalization of Pyrrolidine: Intermolecular [3 + 2] Cycloaddition for the Construction of 2,3-Dihydro-1H-Pyrrolizine Derivatives.

    Zheng, Kai-Lu; Shu, Wen-Ming; Ma, Jun-Rui; Wu, Yan-Dong; Wu, An-Xin

    2016-08-01

    A one-pot acid-mediated reaction has been developed for the N-H/α,β-C(sp(3))-H trifunctionalization of pyrrolidine without any metallic reagents or external oxidants. This reaction involves the intermolecular [3 + 2] cycloaddition of in situ-generated azomethine ylides with acrylic esters to provide facile access to 2,3-dihydro-1H-pyrrolizine derivatives in high yields under mild conditions. PMID:27396906

  2. Abscisic acid induces biosynthesis of bisbibenzyls and tolerance to UV-C in the liverwort Marchantia polymorpha.

    Kageyama, Akito; Ishizaki, Kimitsune; Kohchi, Takayuki; Matsuura, Hideyuki; Takahashi, Kosaku

    2015-09-01

    Environmental stresses are effective triggers for the biosynthesis of various secondary metabolites in plants, and phytohormones such as jasmonic acid and abscisic acid are known to mediate such responses in flowering plants. However, the detailed mechanism underlying the regulation of secondary metabolism in bryophytes remains unclear. In this study, the induction mechanism of secondary metabolites in the model liverwort Marchantia polymorpha was investigated. Abscisic acid (ABA) and ultraviolet irradiation (UV-C) were found to induce the biosynthesis of isoriccardin C, marchantin C, and riccardin F, which are categorized as bisbibenzyls, characteristic metabolites of liverworts. UV-C led to the significant accumulation of ABA. Overexpression of MpABI1, which encodes protein phosphatase 2C (PP2C) as a negative regulator of ABA signaling, suppressed accumulation of bisbibenzyls in response to ABA and UV-C irradiation and conferred susceptibility to UV-C irradiation. These data show that ABA plays a significant role in the induction of bisbibenzyl biosynthesis, which might confer tolerance against UV-C irradiation in M. polymorpha. PMID:26055979

  3. Conclusion on the peer review of the pesticide risk assessment of the active substance S-abscisic acid

    European Food Safety Authority

    2013-08-01

    Full Text Available The conclusions of the European Food Safety Authority (EFSA following the peer review of the initial risk assessments carried out by the competent authority of the rapporteur Member State the Netherlands, for the pesticide active substance S-abscisic acid are reported. The context of the peer review was that required by Commission Regulation EU No 188/2011. The conclusions were reached on the basis of the evaluation of the representative uses of S-abscisic acid as a plant growth regulator on tomato seedlings and grapes. The reliable endpoints concluded as being appropriate for use in regulatory risk assessment, derived from the available studies and literature in the dossier peer reviewed, are presented. Missing information identified as being required by the regulatory framework is listed. Concerns are identified in the areas of residues and ecotoxicology, as the consumer risk assessment and the risk assessment for higher aquatic plants for some metabolites could not be finalised based on the data available.

  4. Alleviation of Osmotic Stress Effects by Exogenous Application of Salicylic or Abscisic Acid on Wheat Seedlings

    Katarzyna Cyganek

    2013-06-01

    Full Text Available The aim of the study was to assess the role of salicylic acid (SA and abscisic acid (ABA in osmotic stress tolerance of wheat seedlings. This was accomplished by determining the impact of the acids applied exogenously on seedlings grown under osmotic stress in hydroponics. The investigation was unique in its comprehensiveness, examining changes under osmotic stress and other conditions, and testing a number of parameters simultaneously. In both drought susceptible (SQ1 and drought resistant (CS wheat cultivars, significant physiological and biochemical changes were observed upon the addition of SA (0.05 mM or ABA (0.1 μM to solutions containing half-strength Hoagland medium and PEG 6000 (−0.75 MPa. The most noticeable result of supplementing SA or ABA to the medium (PEG + SA and PEG + ABA was a decrease in the length of leaves and roots in both cultivars. While PEG treatment reduced gas exchange parameters, chlorophyll content in CS, and osmotic potential, and conversely, increased lipid peroxidation, soluble carbohydrates in SQ1, proline content in both cultivars and total antioxidants activity in SQ1, PEG + SA or PEG + ABA did not change the values of these parameters. Furthermore, PEG caused a two-fold increase of endogenous ABA content in SQ1 and a four-fold increase in CS. PEG + ABA increased endogenous ABA only in SQ1, whereas PEG + SA caused a greater increase of ABA content in both cultivars compared to PEG. In PEG-treated plants growing until the harvest, a greater decrease of yield components was observed in SQ1 than in CS. PEG + SA, and particularly PEG + ABA, caused a greater increase of these yield parameters in CS compared to SQ1. In conclusion, SA and ABA ameliorate, particularly in the tolerant wheat cultivar, the harmful effects and after effects of osmotic stress induced by PEG in hydroponics through better osmotic adjustment achieved by an increase in proline and carbohydrate content as well as by an increase in antioxidant

  5. QTLs and candidate genes for desiccation and abscisic acid content in maize kernels

    Charcosset Alain

    2010-01-01

    Full Text Available Abstract Background Kernel moisture at harvest is an important trait since a low value is required to prevent unexpected early germination and ensure seed preservation. It is also well known that early germination occurs in viviparous mutants, which are impaired in abscisic acid (ABA biosynthesis. To provide some insight into the genetic determinism of kernel desiccation in maize, quantitative trait loci (QTLs were detected for traits related to kernel moisture and ABA content in both embryo and endosperm during kernel desiccation. In parallel, the expression and mapping of genes involved in kernel desiccation and ABA biosynthesis, were examined to detect candidate genes. Results The use of an intermated recombinant inbred line population allowed for precise QTL mapping. For 29 traits examined in an unreplicated time course trial of days after pollination, a total of 78 QTLs were detected, 43 being related to kernel desiccation, 15 to kernel weight and 20 to ABA content. Multi QTL models explained 35 to 50% of the phenotypic variation for traits related to water status, indicating a large genetic control amenable to breeding. Ten of the 20 loci controlling ABA content colocated with previously detected QTLs controlling water status and ABA content in water stressed leaves. Mapping of candidate genes associated with kernel desiccation and ABA biosynthesis revealed several colocations between genes with putative functions and QTLs. Parallel investigation via RT-PCR experiments showed that the expression patterns of the ABA-responsive Rab17 and Rab28 genes as well as the late embryogenesis abundant Emb5 and aquaporin genes were related to desiccation rate and parental allele effect. Database searches led to the identification and mapping of two zeaxanthin epoxidase (ZEP and five novel 9-cis-epoxycarotenoid dioxygenase (NCED related genes, both gene families being involved in ABA biosynthesis. The expression of these genes appeared independent in

  6. 1-Aminocyclopropane-1-carboxylic acid and abscisic acid during the germination of sugar beet (Beta vulgaris L.): a comparative study of fruits and seeds

    Hermann, K.; Meinhard, J.; Dobrev, Petre; Linkies, A.; Pešek, Bedřich; Heß, B.; Macháčková, Ivana; Fischer, U.; Leubner-Metzger, G.

    2007-01-01

    Roč. 58, č. 11 (2007), s. 3047-3060. ISSN 0022-0957 Institutional research plan: CEZ:AV0Z50380511 Keywords : abscisic acid (ABA) * ABA 8'-hydroxylase (CYP707A) * 1-aminocyclopropane-1-carboxylic acid (ACC) Subject RIV: EF - Botanics Impact factor: 3.917, year: 2007

  7. Reduced de-etiolation of hypocotyl growth in a tomato mutant is associated with hypersensitivity to, and high endogenous levels of, abscisic acid

    Fellner, Martin; Zhang, R.; Pharis, R.; Sawhney, V.

    2001-01-01

    Roč. 52, č. 357 (2001), s. 725-738. ISSN 0022-0957 R&D Projects: GA ČR GV521/96/K117 Institutional research plan: CEZ:AV0Z5038910 Keywords : Abscisic acid * elongated mutant * fluridone Subject RIV: EF - Botanics Impact factor: 2.433, year: 2001

  8. Fast and efficient separation of cytokinins from auxin and abscisic acid and their purification using mixed-mode solid-phase extraction

    Dobrev, Petre; Kamínek, Miroslav

    2002-01-01

    Roč. 950, č. 1 (2002), s. 21-29. ISSN 0021-9673 R&D Projects: GA ČR GA206/02/0967; GA ČR GA522/02/0530 Institutional research plan: CEZ:AV0Z5038910 Keywords : cytokinins * abscisic acid * extraction Subject RIV: EF - Botanics Impact factor: 3.098, year: 2002

  9. Characterization of major ripening events during softening in grape: turgor, sugar accumulation, abscisic acid metabolism, colour development, and their relationship with growth.

    Castellarin, Simone D; Gambetta, Gregory A; Wada, Hiroshi; Krasnow, Mark N; Cramer, Grant R; Peterlunger, Enrico; Shackel, Kenneth A; Matthews, Mark A

    2016-02-01

    Along with sugar accumulation and colour development, softening is an important physiological change during the onset of ripening in fruits. In this work, we investigated the relationships among major events during softening in grape (Vitis vinifera L.) by quantifying elasticity in individual berries. In addition, we delayed softening and inhibited sugar accumulation using a mechanical growth-preventing treatment in order to identify processes that are sugar and/or growth dependent. Ripening processes commenced on various days after anthesis, but always at similarly low elasticity and turgor. Much of the softening occurred in the absence of other changes in berry physiology investigated here. Several genes encoding key cell wall-modifying enzymes were not up-regulated until softening was largely completed, suggesting softening may result primarily from decreases in turgor. Similarly, there was no decrease in solute potential, increase in sugar concentration, or colour development until elasticity and turgor were near minimum values, and these processes were inhibited when berry growth was prevented. Increases in abscisic acid occurred early during softening and in the absence of significant expression of the V. vinifera 9-cis-epoxycarotenoid dioxygenases. However, these increases were coincident with decreases in the abscisic acid catabolite diphasic acid, indicating that initial increases in abscisic acid may result from decreases in catabolism and/or exogenous import. These data suggest that softening, decreases in turgor, and increases in abscisic acid represent some of the earliest events during the onset of ripening. Later, physical growth, further increases in abscisic acid, and the accumulation of sugar are integral for colour development. PMID:26590311

  10. Structural Insights into Maize Viviparous14, a Key Enzyme in the Biosynthesis of the Phytohormone Abscisic Acid W

    Messing, S.; Gabelli, S; Echeverria, I; Vogel, J; Guan, J; Tan, B; Klee, H; McCarty, D; Amzela, M

    2010-01-01

    The key regulatory step in the biosynthesis of abscisic acid (ABA), a hormone central to the regulation of several important processes in plants, is the oxidative cleavage of the 11,12 double bond of a 9-cis-epoxycarotenoid. The enzyme viviparous14 (VP14) performs this cleavage in maize (Zea mays), making it a target for the rational design of novel chemical agents and genetic modifications that improve plant behavior through the modulation of ABA levels. The structure of VP14, determined to 3.2-{angstrom} resolution, provides both insight into the determinants of regio- and stereospecificity of this enzyme and suggests a possible mechanism for oxidative cleavage. Furthermore, mutagenesis of the distantly related CCD1 of maize shows how the VP14 structure represents a template for all plant carotenoid cleavage dioxygenases (CCDs). In addition, the structure suggests how VP14 associates with the membrane as a way of gaining access to its membrane soluble substrate.

  11. Effects of Formulated Fertilizer Synergist on Abscisic Acid Accumulation, Proline Content and Photosynthetic Characteristics of Rice under Drought

    WANG Shao-xian; XIA Shi-tou; PENG Ke-qin; KUANG Feng-chun; CAO Yong; XIAO Lang-tao

    2007-01-01

    To investigate the effects of formulated fertilizer synergist on the drought tolerance in rice, pot experiment was conducted to analyze the photosynthetic characteristics and the accumulation of abscisic acid (ABA) and proline in middle-season rice variety Peiliangyou 93. The synergist could improve the net photosynthetic rate, and coordination between the water loss and the CO2 absorption as well as reduce the harmful effect on photosynthetic process under drought conditions. Under drought, the ABA accumulated massively both in roots and leaves, while the ABA content in roots was far higher than that in leaves. The results indicate that synergist could increase the ABA accumulation, but reduce the proline accumulation in rice plant under drought.

  12. Comparative effects of auxin and abscisic acid on growth, hydrogen ion efflux and gravitropism in primary roots of maize

    Evans, M. L.; Mulkey, T. J.

    1984-01-01

    In order to test the idea that auxin action on root growth may be mediated by H(+) movement, the correlation of auxin action on growth and H(+) movement in roots was examined along with changes in H(+) efflux patterns associated with the asymmetric growth which occurs during gravitropism. The effects of indoleacetic acid (IAA) and abscisic acid (AbA) on growth, H(+) secretion, and gravitropism in roots were compared. Results show a close correlation existent between H(+) efflux and growth in maize roots. In intact roots there is strong H(+) efflux from the elongation zone. Growth-promoting concentrations of IAA stimulate H(+) efflux. During gravitropism the H(+) efflux from the elongation zone becomes asymmetric; the evidence indicates that auxin redistribution contributes to the development of acid efflux asymmetry. That AbA stimulates root growth is reflected in its ability to stimulate H(+) efflux from apical root segments.

  13. Structural Insights into Maize Viviparous14, a Key Enzyme in the Biosynthesis of the Phytohormone Abscisic Acid

    Messing, Simon A.J.; Gabelli, Sandra B.; Echeverria, Ignacia; Vogel, Jonathan T.; Guan, Jiahn Chou; Tan, Bao Cai; Klee, Harry J.; McCarty, Donald R.; Amzel, L. Mario (JHU); (Florida)

    2011-09-06

    The key regulatory step in the biosynthesis of abscisic acid (ABA), a hormone central to the regulation of several important processes in plants, is the oxidative cleavage of the 11,12 double bond of a 9-cis-epoxycarotenoid. The enzyme viviparous14 (VP14) performs this cleavage in maize (Zea mays), making it a target for the rational design of novel chemical agents and genetic modifications that improve plant behavior through the modulation of ABA levels. The structure of VP14, determined to 3.2-{angstrom} resolution, provides both insight into the determinants of regio- and stereospecificity of this enzyme and suggests a possible mechanism for oxidative cleavage. Furthermore, mutagenesis of the distantly related CCD1 of maize shows how the VP14 structure represents a template for all plant carotenoid cleavage dioxygenases (CCDs). In addition, the structure suggests how VP14 associates with the membrane as a way of gaining access to its membrane soluble substrate.

  14. Up-regulation of abscisic acid signaling pathway facilitates aphid xylem absorption and osmoregulation under drought stress.

    Guo, Huijuan; Sun, Yucheng; Peng, Xinhong; Wang, Qinyang; Harris, Marvin; Ge, Feng

    2016-02-01

    The activation of the abscisic acid (ABA) signaling pathway reduces water loss from plants challenged by drought stress. The effect of drought-induced ABA signaling on the defense and nutrition allocation of plants is largely unknown. We postulated that these changes can affect herbivorous insects. We studied the effects of drought on different feeding stages of pea aphids in the wild-type A17 of Medicago truncatula and ABA signaling pathway mutant sta-1. We examined the impact of drought on plant water status, induced plant defense signaling via the abscisic acid (ABA), jasmonic acid (JA), and salicylic acid (SA) pathways, and on the host nutritional quality in terms of leaf free amino acid content. During the penetration phase of aphid feeding, drought decreased epidermis/mesophyll resistance but increased mesophyll/phloem resistance of A17 but not sta-1 plants. Quantification of transcripts associated with ABA, JA and SA signaling indicated that the drought-induced up-regulation of ABA signaling decreased the SA-dependent defense but increased the JA-dependent defense in A17 plants. During the phloem-feeding phase, drought had little effect on the amino acid concentrations and the associated aphid phloem-feeding parameters in both plant genotypes. In the xylem absorption stage, drought decreased xylem absorption time of aphids in both genotypes because of decreased water potential. Nevertheless, the activation of the ABA signaling pathway increased water-use efficiency of A17 plants by decreasing the stomatal aperture and transpiration rate. In contrast, the water potential of sta-1 plants (unable to close stomata) was too low to support xylem absorption activity of aphids; the aphids on sta-1 plants had the highest hemolymph osmolarity and lowest abundance under drought conditions. Taken together this study illustrates the significance of cross-talk between biotic-abiotic signaling pathways in plant-aphid interaction, and reveals the mechanisms leading to alter

  15. Abscisic Acid and Cytokinin-Induced Osmotic and Antioxidant Regulation in Two Drought-Tolerant and Drought-Sensitive Cultivars of Wheat During Grain Filling Under Water Deficit in Field Conditions

    Mohammad-Reza SARAFRAZ-ARDAKANI

    2014-09-01

    Full Text Available Phytohormones play critical roles in regulating plant responses to stress. The present study investigates the effect of cytokinin, abscisic acid and cytokinin/abscisic acid interaction on some osmoprotectants and antioxidant parameters induced by drought stress in two wheat cultivars (Triticum aestivum L. of ‘Pishgam’ and ‘MV-17’ as tolerant and sensitive to drought during post-anthesis phase, respectively grown in field conditions. The most considerable effect of the treatments was exhibited 21 days after anthesis. Under drought conditions, the flag leaf soluble carbohydrate content increased in both cultivars while starch content was remarkably decreased in ‘Pishgam’ as compared to ‘MV-17’. Abscisic acid increased total soluble sugar and reduced starch more than other hormonal treatments, although it decreased studied monosaccharaides in ‘Pishgam’, especially. Drought stress induced high proportion of gylycinebetain and free proline in ‘Pishgam’ cultivar. Application of abscisic acid and cytokinin/abscisic acid interaction increased gylycinebetain and proline content in both cultivars under irrigation and drought conditions. The tolerant cultivar exhibited less accumulation of hydrogen peroxide and malondialdehyde in relation to significant increase of catalase and peroxidase activities and α-tocpherol content under drought conditions. All hormonal treatments increased the named enzyme activities under both irrigation and drought conditions, while higher accumulation of α-tocopherol was only showed in case of cytokinin application. Also, abscisic acid and cytokinin/abscisic acid could decrease drought-induced hydrogen peroxide and malondialdehyde level to some extent, although abscisic acid increased both of hydrogen peroxide andmalondialdehyde content in irrigation phase, especially.

  16. Abscisic Acid and Cytokinin-Induced Osmotic and Antioxidant Regulation in Two Drought-Tolerant and Drought-Sensitive Cultivars of Wheat During Grain Filling Under Water Deficit in Field Conditions

    2014-01-01

    Phytohormones play critical roles in regulating plant responses to stress. The present study investigates the effect of cytokinin, abscisic acid and cytokinin/abscisic acid interaction on some osmoprotectants and antioxidant parameters induced by drought stress in two wheat cultivars (Triticum aestivum L.) of ‘Pishgam’ and ‘MV-17’ as tolerant and sensitive to drought during post-anthesis phase, respectively grown in field conditions. The most considerable effect of the treatments was exhibite...

  17. Major latex protein-like protein 43 (MLP43) functions as a positive regulator during abscisic acid responses and confers drought tolerance in Arabidopsis thaliana

    WANG, YANPING; Yang, Li; Chen, Xi; Ye, Tiantian; Zhong, Bao; Liu, Ruijie; Wu, Yan; Chan, Zhulong

    2015-01-01

    Drought stress is one of the disadvantageous environmental conditions for plant growth and reproduction. Given the importance of abscisic acid (ABA) to plant growth and abiotic stress responses, identification of novel components involved in ABA signalling transduction is critical. In this study, we screened numerous Arabidopsis thaliana mutants by seed germination assay and identified a mutant mlp43 (major latex protein-like 43) with decreased ABA sensitivity in seed germination. The mlp43 m...

  18. Antagonistic roles of abscisic acid and cytokinin during response to nitrogen depletion in oleaginous microalga Nannochloropsis oceanica expand the evolutionary breadth of phytohormone function

    Lu, Y.; Tarkowská, Danuše; Turečková, Veronika; Luo, T.; Xin, Y.; Li, J.; Wang, Q.; Jiao, N.; Strnad, Miroslav; Xu, J.

    2014-01-01

    Roč. 80, č. 1 (2014), s. 52-68. ISSN 0960-7412 R&D Projects: GA ČR GA206/09/1284; GA MŠk LK21306; GA MŠk(CZ) LO1204 Grant ostatní: GA MŠk(CZ) ED0007/01/01 Institutional support: RVO:61389030 Keywords : Nannochloropsis oceanica * antagonistic synergy * abscisic acid Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 5.972, year: 2014

  19. ASCORBATE PEROXIDASE6 protects Arabidopsis desiccating and germinating seeds from stress and mediates cross talk between reactive oxygen species, abscisic acid, and auxin

    Chen, Ch.; Letnik, I.; Hacham, Y.; Dobrev, Petre; Ben-Daniel, B.H.; Vaňková, Radomíra; Amir, R.; Miller, G.

    2014-01-01

    Roč. 166, č. 1 (2014), s. 370-383. ISSN 0032-0889 R&D Projects: GA ČR GA206/09/2062 Institutional support: RVO:61389030 Keywords : Arabidopsis thaliana * abscisic acid * germinating seeds Subject RIV: ED - Physiology Impact factor: 6.841, year: 2014 http://gateway.isiknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=Alerting&SrcApp=Alerting&DestApp=MEDLINE&DestLinkType=FullRecord&UT=25049361

  20. A GH3 family member, OsGH3-2, modulates auxin and abscisic acid levels and differentially affects drought and cold tolerance in rice

    Du, Hao; Wu, Nai; Fu, Jing; Wang, Shiping; Li, Xianghua; Xiao, Jinghua; Xiong, Lizhong

    2012-01-01

    Plant responses to abiotic stresses are coordinated by arrays of growth and developmental processes. Indole-3-acetic acid (IAA) and abscisic acid (ABA) play critical roles in developmental programmes and environmental responses, respectively, through complex signalling and metabolism networks. However, crosstalk between the two phytohormones in the stress responses remains largely unknown. Here, it is reported that a GH3 family gene, OsGH3-2, encoding an enzyme catalysing IAA conjugation to a...

  1. Chemical ionization mass spectrometry of indol-3yl-acetic acid and cis-abscisic acid: evaluation of negative ion detection and quantification of cis-abscisic acid in growing maize roots

    Mass spectra of the derivatives of indol-3yl-acetic acid and cis-abscisic acid were obtained in electron impact and chemical ionization positive ion and negative ion modes. The respective merits of methane, isobutane, and ammonia as reagent gases for structure determination and sensitive detection were compared using the methyl esters. From one to 10 fluorine atoms were attached to IAA to improve the electron-capturing properties of the molecule. The best qualitative information was obtained when using positive ion chemical ionization with methane. However, the most sensitive detection, with at least two ions per molecule, was achieved by electron impact on the IAA-HFB-ME derivative and by negative ion chemical ionization with NH3 on the ABA-methyl ester derivative. p ]Quantitative analyses of ABA in different parts of maize (Zea mays cv. LG 11) root tips were performed by the latter technique. It was found that the cap and apex contained less ABA than the physiologically older parts of the root such as the elongation zone and the more differentiated tissues. This technique was also used to show a relation between maize root growth and the endogenous ABA level of the elongation zone and root tip: there is more ABA in the slowly growing roots than in the rapidly growing ones. (author)

  2. Plant, cell, and molecular mechanisms of abscisic-acid regulation of stomatal apertures. In vivo phosphorylation of phosphoenolpyruvate carboxylase in guard cells of Vicia faba L. is enhanced by fusicoccin and suppressed by abscisic acid

    Du, Z.; Aghoram, K.; Outlaw, W.H. Jr.

    1996-12-31

    Plants regulate water loss and CO{sub 2} gain by modulating the aperture sizes of stomata that penetrate the epidermis. Aperture size itself is increased by osmolyte accumulation and consequent turgor increase in the pair of guard cells that flank each stoma. Guard-cell phosphoenolpyruvate carboxylase, which catalyzes the regulated step leading to malate synthesis, is crucial for charge and pH maintenance during osmolyte accumulation. Regulation of this cytosolic enzyme by effectors is well documented, but additional regulation by posttranslational modification is predicted by the alteration of PEPC kinetics during stomatal opening. In this study, the authors have investigated whether this alteration is associated with the phosphorylation status of this enzyme. Using sonicated epidermal peels (isolated guard cells) pre-loaded with {sub 32}PO{sub 4}, the authors induced stomatal opening and guard-cell malate accumulation by incubation with 5 {micro}M fusicoccin (FC). In corroboratory experiments, guard cells were incubated with 5 {micro}M fusicoccin (FC). In corroboratory experiments, guard cells were incubated with the FC antagonist, 10 {micro}M abscisic acid (ABA). The phosphorylation status of PEPC was assessed by immunoprecipitation, electrophoresis, immunoblotting, and autoradiography. PEPC was phosphorylated when stomata were stimulated to open, and phosphorylation was lessened by incubation with ABA.

  3. Función de OCP3 en la resistencia de Arabidopsis frente a hongos necrotrofos.

    García-Andrade Serrano, Javier

    2016-01-01

    [EN] ocp3 mutant plants exhibit an accelerated and intensified callose deposition in response to infection by Botrytis cinerea or Plectosphaerella cucumerina. After phenotypic analysis of a series of double mutants ocp3 we observed that both, the increase callose deposition and resistance, require PMR4 callose synthase and hormone abscisic acid (ABA). In wild plants after infection with any of these necrotrophic fungi, ABA synthesis increases, this increase is even higher in ocp3. The greater...

  4. Study on the distribution of callose and β-1,3-D-glucanase in Chenopodium quinoa by immuno-gold labeling%免疫胶体金标记定位昆诺藜中的胼胝质和胼胝质降解酶

    李云琴; 王华; 谢礼; 洪健

    2014-01-01

    运用免疫胶体金技术研究了感染蚕豆萎蔫病毒2号以及健康昆诺藜细胞中胼胝质和胼胝质降解酶的分布情况。电镜观察发现胶体金特异性标记在含有VP37小管的胞间运动通道周围,其余区域感病和健康细胞的胼胝质及胼胝质降解酶分布差别不大,胼胝质主要分布于细胞间隙的大块电子致密物质以及细胞壁结构发生较大变化的区域,胼胝质降解酶主要分布于筛板、维管束细胞紧贴细胞壁区域的大块电子致密物质上,在细胞壁结构发生较大改变的区域也有胼胝质降解酶的分布。推测胼胝质在昆诺藜细胞中的积累和降解可能与细胞壁结构成分改变有关。%The distribution of callose and β⁃1,3⁃D⁃glucanase in the Broad bean wilt virus 2 ( BBWV 2 ) infected and the healthy Chenopodium quinoa was investigated by using immuno⁃gold labeling with the antibody against callose and β⁃1, 3⁃D⁃glucanase, respectively. The results show that, except for the VP37 intercellular moving cell wall pathways, there is no obvious difference on the distribution of callose and β⁃1,3⁃D⁃glucanase between the infected and healthy cells. Callose is mainly distributed on the regions as bellow:the electron condensed material which located in the intercellular space, the structural altered region of cell wall and the cell wall broken region. Glucanase is mainly distributed on the regions as bellow:the sieve plate, the electron condensed material attached to cell wall in the vascular bundle and the structural altered region of cell wall. From these results, it can be deduced that the accumulation and degradation of callose in C. quinoa is related to the cell wall structural and component alteration.

  5. Abscisic acid regulates root growth under osmotic stress conditions via an interacting hormonal network with cytokinin, ethylene and auxin.

    Rowe, James H; Topping, Jennifer F; Liu, Junli; Lindsey, Keith

    2016-07-01

    Understanding the mechanisms regulating root development under drought conditions is an important question for plant biology and world agriculture. We examine the effect of osmotic stress on abscisic acid (ABA), cytokinin and ethylene responses and how they mediate auxin transport, distribution and root growth through effects on PIN proteins. We integrate experimental data to construct hormonal crosstalk networks to formulate a systems view of root growth regulation by multiple hormones. Experimental analysis shows: that ABA-dependent and ABA-independent stress responses increase under osmotic stress, but cytokinin responses are only slightly reduced; inhibition of root growth under osmotic stress does not require ethylene signalling, but auxin can rescue root growth and meristem size; osmotic stress modulates auxin transporter levels and localization, reducing root auxin concentrations; PIN1 levels are reduced under stress in an ABA-dependent manner, overriding ethylene effects; and the interplay among ABA, ethylene, cytokinin and auxin is tissue-specific, as evidenced by differential responses of PIN1 and PIN2 to osmotic stress. Combining experimental analysis with network construction reveals that ABA regulates root growth under osmotic stress conditions via an interacting hormonal network with cytokinin, ethylene and auxin. PMID:26889752

  6. Gene Overexpression and RNA Silencing Tools for the Genetic Manipulation of the S-(+-Abscisic Acid Producing Ascomycete Botrytis cinerea

    Zhong-Tao Ding

    2015-05-01

    Full Text Available The phytopathogenic ascomycete Botrytis cinerea produces several secondary metabolites that have biotechnical significance and has been particularly used for S-(+-abscisic acid production at the industrial scale. To manipulate the expression levels of specific secondary metabolite biosynthetic genes of B. cinerea with Agrobacterium tumefaciens-mediated transformation system, two expression vectors (pCBh1 and pCBg1 with different selection markers and one RNA silencing vector, pCBSilent1, were developed with the In-Fusion assembly method. Both expression vectors were highly effective in constitutively expressing eGFP, and pCBSilent1 effectively silenced the eGFP gene in B. cinerea. Bcaba4, a gene suggested to participate in ABA biosynthesis in B. cinerea, was then targeted for gene overexpression and RNA silencing with these reverse genetic tools. The overexpression of bcaba4 dramatically induced ABA formation in the B. cinerea wild type strain Bc-6, and the gene silencing of bcaba4 significantly reduced ABA-production in an ABA-producing B. cinerea strain.

  7. Kinetic Characterisation of a Single Chain Antibody against the Hormone Abscisic Acid: Comparison with Its Parental Monoclonal

    Badescu, George O.; Marsh, Andrew; Smith, Timothy R.; Thompson, Andrew J.; Napier, Richard M.

    2016-01-01

    A single-chain Fv fragment antibody (scFv) specific for the plant hormone abscisic acid (ABA) has been expressed in the bacterium Escherichia coli as a fusion protein. The kinetics of ABA binding have been measured using surface plasmon resonance spectrometry (BIAcore 2000) using surface and solution assays. Care was taken to calculate the concentration of active protein in each sample using initial rate measurements under conditions of partial mass transport limitation. The fusion product, parental monoclonal antibody and the free scFv all have low nanomolar affinity constants, but there is a lower dissociation rate constant for the parental monoclonal resulting in a three-fold greater affinity. Analogue specificity was tested and structure-activity binding preferences measured. The biologically-active (+)-ABA enantiomer is recognised with an affinity three orders of magnitude higher than the inactive (-)-ABA. Metabolites of ABA including phaseic acid, dihydrophaseic acid and deoxy-ABA have affinities over 100-fold lower than that for (+)-ABA. These properties of the scFv make it suitable as a sensor domain in bioreporters specific for the naturally occurring form of ABA. PMID:27023768

  8. Low irradiances affect abscisic acid, indole-3-acidic acid, and cytokinin levels of wheat (Triticum aestivum L.) tissues

    Nan, R.; Carman, J. G.; Salisbury, F. B.

    1999-01-01

    Wheat (Triticum aestivum L.) plants were grown under four irradiance levels: 1,400, 400, 200, and 100 micromol m-2 s-1. Leaves and roots were sampled before, during, and after the boot stage, and levels of abscisic acid (ABA), indole-3-acetic acid (IAA), zeatin, zeatin riboside, dihydrozeatin, dihydrozeatin riboside, isopentenyl adenine, and isopentenyl adenosine were quantified using noncompetitive indirect ELISA systems. Levels of IAA in leaves and roots of plants exposed to 100 micromol m-2 s-1 of irradiance were 0.7 and 2.9 micromol kg-1 dry mass (DM), respectively. These levels were 0.2 and 1.0 micromol kg-1 DM, respectively, when plants were exposed to 1,400 micromol m-2 s-1. Levels of ABA in leaves and roots of plants exposed to 100 micromol m-2 s-1 were 0.65 and 0.55 micromol kg-1 DM, respectively. They were 0.24 micromol kg-1 DM (both leaves and roots) when plants were exposed to 1,400 micromol m-2 s-1. Levels of isopentenyl adenosine in leaves (24.3 nmol kg-1 DM) and roots (29.9 nmol kg-1 DM) were not affected by differences in the irradiance regime. Similar values were obtained in a second experiment. Other cytokinins could not be detected (<10 nmol kg 1 DM) in either experiment with the sample sizes used (150-600 mg DM for roots and shoots, respectively).

  9. The parasitic plant Cuscuta australis is highly insensitive to abscisic acid-induced suppression of hypocotyl elongation and seed germination.

    Li, Juan; Hettenhausen, Christian; Sun, Guiling; Zhuang, Huifu; Li, Jian-Hong; Wu, Jianqiang

    2015-01-01

    Around 1% of angiosperms are parasitic plants. Their growth and development solely or partly depend on host plants from which they extract water, nutrients, and other molecules using a parasitic plant-specific organ, the haustorium. Strong depletion of nutrients can result in serious growth retardation and in some cases, death of the hosts. The genus Cuscuta (dodder) comprises about 200 holoparasitic species occurring on all continents. Their seedlings have no roots and cotyledons but are only string-like hypocotyls. When they contact suitable host plants, haustoria are formed and thereafter seedlings rapidly develop into vigorously growing branches without roots and leaves. This highly specialized lifestyle suggests that Cuscuta plants likely have unique physiology in development and stress responses. Using germination and seedling growth assays, we show that C. australis seeds and seedlings are highly insensitive to abscisic acid (ABA). Transcriptome analysis and protein sequence alignment with Arabidopsis, tomato, and rice homologs revealed that C. australis most likely consists of only four functional ABA receptors. Given that Cuscuta plants are no longer severely challenged by drought stress, we hypothesize that the ABA-mediated drought resistance pathway in Cuscuta spp. might have had degenerated over time during evolution. PMID:26258814

  10. The plant cuticle is required for osmotic stress regulation of abscisic acid biosynthesis and osmotic stress tolerance in Arabidopsis

    Wang, Zhenyu

    2011-05-01

    Osmotic stress activates the biosynthesis of abscisic acid (ABA). One major step in ABA biosynthesis is the carotenoid cleavage catalyzed by a 9-cis epoxycarotenoid dioxygenase (NCED). To understand the mechanism for osmotic stress activation of ABA biosynthesis, we screened for Arabidopsis thaliana mutants that failed to induce the NCED3 genee xpression in response to osmotic stress treatments. The ced1 (for 9-cis epoxycarotenoid dioxy genase defective 1) mutant isolated in this study showed markedly reduced expression of NCED3 in response to osmotic stress (polyethylene glycol)treatments compared with the wild type. Other ABA biosynthesis genes are also greatly reduced in ced1 under osmotic stress. ced1 mutant plants are very sensitive to even mild osmotic stress. Map-based cloning revealed unexpectedly thatCED1 encodes a putative a/b hydrolase domain-containing protein and is allelic to the BODYGUARD gene that was recently shown to be essential for cuticle biogenesis. Further studies discovered that other cut in biosynthesis mutants are also impaired in osmotic stress induction of ABA biosynthesis genes and are sensitive to osmotic stress. Our work demonstrates that the cuticle functions not merely as a physical barrier to minimize water loss but also mediates osmotic stress signaling and tolerance by regulating ABA biosynthesis and signaling. © 2011 American Society of Plant Biologists. All rights reserved.

  11. Abscisic acid and ethylene in mutants of Arabidopsis thaliana differing in their resistance to ultraviolet (UV-B) radiation stress

    The effects of ultraviolet irradiation (between 280 and 320 nm) on plant survival, ethylene evolution, and abscisic acid (ABA) content were studied in Arabidopsis thaliana (L.) Heunh. plants. Three genetic lines of Arabidopsis differing in their resistance to ultraviolet (UV-B) radiation stress were used. UV-B irradiation had detrimental effects on plant survival, enhanced ethylene evolution, and increased ABA content in the plants of all three lines. The higher ultraviolet dose was absorbed, the less was the number of surviving plants and the higher were the levels of both phytohormones. The maximum ethylene evolution occurred during the initial two to four hours after irradiation, but the ABA content peaked only after 24 h. The most resistant line showed the highest ABA content and the fastest ethylene evolution, whereas, in the susceptible line, both indices were the lowest. After UV-B treatment, the ABA-deficient Arabidopsis mutant evolved four to six times more ethylene than the plants with normal ABA content. Stress ethylene production evidently did not depend on the level of endogenous ABA as the kinetics of ethylene evolution was similar in the ABA-deficient mutant and in other studied Arabidopsis lines

  12. Genetic analyses of interactions among gibberellin, abscisic acid, and brassinosteroids in the control of flowering time in Arabidopsis thaliana.

    Malgorzata A Domagalska

    Full Text Available BACKGROUND: Genetic interactions between phytohormones in the control of flowering time in Arabidopsis thaliana have not been extensively studied. Three phytohormones have been individually connected to the floral-timing program. The inductive function of gibberellins (GAs is the most documented. Abscisic acid (ABA has been demonstrated to delay flowering. Finally, the promotive role of brassinosteroids (BRs has been established. It has been reported that for many physiological processes, hormone pathways interact to ensure an appropriate biological response. METHODOLOGY: We tested possible genetic interactions between GA-, ABA-, and BR-dependent pathways in the control of the transition to flowering. For this, single and double mutants deficient in the biosynthesis of GAs, ABA, and BRs were used to assess the effect of hormone deficiency on the timing of floral transition. Also, plants that over-express genes encoding rate-limiting enzymes in each biosynthetic pathway were generated and the flowering time of these lines was investigated. CONCLUSIONS: Loss-of-function studies revealed a complex relationship between GAs and ABA, and between ABA and BRs, and suggested a cross-regulatory relation between GAs to BRs. Gain-of-function studies revealed that GAs were clearly limiting in their sufficiency of action, whereas increases in BRs and ABA led to a more modest phenotypic effect on floral timing. We conclude from our genetic tests that the effects of GA, ABA, and BR on timing of floral induction are only in partially coordinated action.

  13. Abscisic acid-induced rearrangement of intracellular structures associated with freezing and desiccation stress tolerance in the liverwort Marchantia polymorpha.

    Akter, Khaleda; Kato, Masahiro; Sato, Yuki; Kaneko, Yasuko; Takezawa, Daisuke

    2014-09-15

    The plant growth regulator abscisic acid (ABA) is known to be involved in triggering responses to various environmental stresses such as freezing and desiccation in angiosperms, but little is known about its role in basal land plants, especially in liverworts, representing the earliest land plant lineage. We show here that survival rate after freezing and desiccation of Marchantia polymorpha gemmalings was increased by pretreatment with ABA in the presence of increasing concentrations of sucrose. ABA treatment increased accumulation of soluble sugars in gemmalings, and sugar accumulation was further increased by addition of sucrose to the culture medium. ABA treatment of gemmalings also induced accumulation of transcripts for proteins with similarity to late embryogenesis abundant (LEA) proteins, which accumulate in association with acquisition of desiccation tolerance in maturing seeds. Observation by light and electron microscopy indicated that the ABA treatment caused fragmentation of vacuoles with increased cytosolic volume, which was more prominent in the presence of a high concentration of external sucrose. ABA treatment also increased the density of chloroplast distribution and remarkably enlarged their volume. These results demonstrate that ABA induces drastic physiological changes in liverwort cells for stress tolerance, accompanied by accumulation of protectants against dehydration and rearrangement and morphological alterations of cellular organelles. PMID:25046754

  14. Epoxycarotenoid-mediated synthesis of abscisic acid in Physcomitrella patens implicating conserved mechanisms for acclimation to hyperosmosis in embryophytes.

    Takezawa, Daisuke; Watanabe, Naoki; Ghosh, Totan Kumar; Saruhashi, Masashi; Suzuki, Atsushi; Ishiyama, Kanako; Somemiya, Shinnosuke; Kobayashi, Masatomo; Sakata, Yoichi

    2015-04-01

    Plants acclimate to environmental stress signals such as cold, drought and hypersalinity, and provoke internal protective mechanisms. Abscisic acid (ABA), a carotenoid-derived phytohormone, which increases in response to the stress signals above, has been suggested to play a key role in the acclimation process in angiosperms, but the role of ABA in basal land plants such as mosses, including its biosynthetic pathways, has not been clarified. Targeted gene disruption of PpABA1, encoding zeaxanthin epoxidase in the moss Physcomitrella patens was conducted to determine the role of endogenous ABA in acclimation processes in mosses. The generated ppaba1 plants were found to accumulate only a small amount of endogenous ABA. The ppaba1 plants showed reduced osmotic acclimation capacity in correlation with reduced dehydration tolerance and accumulation of late embryogenesis abundant proteins. By contrast, cold-induced freezing tolerance was less affected in ppaba1, indicating that endogenous ABA does not play a major role in the regulation of cold acclimation in the moss. Our results suggest that the mechanisms for osmotic acclimation mediated by carotenoid-derived synthesis of ABA are conserved in embryophytes and that acquisition of the mechanisms played a crucial role in terrestrial adaptation and colonization by land plant ancestors. PMID:25545104

  15. Putrescine is involved in Arabidopsis freezing tolerance and cold acclimation by regulating abscisic acid levels in response to low temperature.

    Cuevas, Juan C; López-Cobollo, Rosa; Alcázar, Rubén; Zarza, Xavier; Koncz, Csaba; Altabella, Teresa; Salinas, Julio; Tiburcio, Antonio F; Ferrando, Alejandro

    2008-10-01

    The levels of endogenous polyamines have been shown to increase in plant cells challenged with low temperature; however, the functions of polyamines in the regulation of cold stress responses are unknown. Here, we show that the accumulation of putrescine under cold stress is essential for proper cold acclimation and survival at freezing temperatures because Arabidopsis (Arabidopsis thaliana) mutants defective in putrescine biosynthesis (adc1, adc2) display reduced freezing tolerance compared to wild-type plants. Genes ADC1 and ADC2 show different transcriptional profiles upon cold treatment; however, they show similar and redundant contributions to cold responses in terms of putrescine accumulation kinetics and freezing sensitivity. Our data also demonstrate that detrimental consequences of putrescine depletion during cold stress are due, at least in part, to alterations in the levels of abscisic acid (ABA). Reduced expression of NCED3, a key gene involved in ABA biosynthesis, and down-regulation of ABA-regulated genes are detected in both adc1 and adc2 mutant plants under cold stress. Complementation analysis of adc mutants with ABA and reciprocal complementation tests of the aba2-3 mutant with putrescine support the conclusion that putrescine controls the levels of ABA in response to low temperature by modulating ABA biosynthesis and gene expression. PMID:18701673

  16. Characterization of the 9-cis-epoxycarotenoid dioxygenase gene family and the regulation of abscisic acid biosynthesis in avocado.

    Chernys, J T; Zeevaart, J A

    2000-09-01

    Avocado (Persea americana Mill. cv Lula) is a climacteric fruit that exhibits a rise in ethylene as the fruit ripens. This rise in ethylene is followed by an increase in abscisic acid (ABA), with the highest level occurring just after the peak in ethylene production. ABA is synthesized from the cleavage of carotenoid precursors. The cleavage of carotenoid precursors produces xanthoxin, which can subsequently be converted into ABA via ABA-aldehyde. Indirect evidence indicates that the cleavage reaction, catalyzed by 9-cis-epoxycarotenoid dioxygenase (NCED), is the regulatory step in ABA synthesis. Three genes encoding NCED cleavage-like enzymes were cloned from avocado fruit. Two genes, PaNCED1 and PaNCED3, were strongly induced as the fruit ripened. The other gene, PaNCED2, was constitutively expressed during fruit ripening, as well as in leaves. This gene lacks a predicted chloroplast transit peptide. It is therefore unlikely to be involved in ABA biosynthesis. PaNCED1 was induced by water stress, but expression of PaNCED3 was not detectable in dehydrated leaves. Recombinant PaNCED1 and PaNCED3 were capable of in vitro cleavage of 9-cis-xanthophylls into xanthoxin and C(25)-apocarotenoids, but PaNCED2 was not. Taken together, the results indicate that ABA biosynthesis in avocado is regulated at the level of carotenoid cleavage. PMID:10982448

  17. Endogenous abscisic acid promotes hypocotyl growth and affects endoreduplication during dark-induced growth in tomato (Solanum lycopersicum L..

    Jan F Humplík

    Full Text Available Dark-induced growth (skotomorphogenesis is primarily characterized by rapid elongation of the hypocotyl. We have studied the role of abscisic acid (ABA during the development of young tomato (Solanum lycopersicum L. seedlings. We observed that ABA deficiency caused a reduction in hypocotyl growth at the level of cell elongation and that the growth in ABA-deficient plants could be improved by treatment with exogenous ABA, through which the plants show a concentration dependent response. In addition, ABA accumulated in dark-grown tomato seedlings that grew rapidly, whereas seedlings grown under blue light exhibited low growth rates and accumulated less ABA. We demonstrated that ABA promotes DNA endoreduplication by enhancing the expression of the genes encoding inhibitors of cyclin-dependent kinases SlKRP1 and SlKRP3 and by reducing cytokinin levels. These data were supported by the expression analysis of the genes which encode enzymes involved in ABA and CK metabolism. Our results show that ABA is essential for the process of hypocotyl elongation and that appropriate control of the endogenous level of ABA is required in order to drive the growth of etiolated seedlings.

  18. Meristem maintenance, auxin, jasmonic and abscisic acid pathways as a mechanism for phenotypic plasticity in Antirrhinum majus.

    Weiss, Julia; Alcantud-Rodriguez, Raquel; Toksöz, Tugba; Egea-Cortines, Marcos

    2016-01-01

    Plants grow under climatic changing conditions that cause modifications in vegetative and reproductive development. The degree of changes in organ development i.e. its phenotypic plasticity seems to be determined by the organ identity and the type of environmental cue. We used intraspecific competition and found that Antirrhinum majus behaves as a decoupled species for lateral organ size and number. Crowding causes decreases in leaf size and increased leaf number whereas floral size is robust and floral number is reduced. Genes involved in shoot apical meristem maintenance like ROA and HIRZ, cell cycle (CYCD3a; CYCD3b, HISTONE H4) or organ polarity (GRAM) were not significantly downregulated under crowding conditions. A transcriptomic analysis of inflorescence meristems showed Gene Ontology enriched pathways upregulated including Jasmonic and Abscisic acid synthesis and or signalling. Genes involved in auxin synthesis such as AmTAR2 and signalling AmANT were not affected by crowding. In contrast, AmJAZ1, AmMYB21, AmOPCL1 and AmABA2 were significantly upregulated. Our work provides a mechanistic working hypothesis where a robust SAM and stable auxin signalling enables a homogeneous floral size while changes in JA and ABA signalling maybe responsible for the decreased leaf size and floral number. PMID:26804132

  19. Implication of abscisic acid on ripening and quality in sweet cherries: differential effects during pre- and postharvest

    Verónica eTijero

    2016-05-01

    Full Text Available Sweet cherry, a non-climacteric fruit, is usually cold-stored during postharvest to prevent over-ripening. The aim of the study was to evaluate the role of abscisic acid (ABA on fruit growth and ripening of this fruit, considering as well its putative implication in over-ripening and effects on quality. We measured the endogenous concentrations of ABA during the ripening of sweet cherries (Prunus avium L. var. Prime Giant collected from orchard trees and in cherries exposed to 4ºC and 23ºC during 10d of postharvest. Furthermore, we examined to what extent endogenous ABA concentrations were related to quality parameters, such as fruit biomass, anthocyanin accumulation and levels of vitamins C and E. Endogenous concentrations of ABA in fruits increased progressively during fruit growth and ripening on the tree, to decrease later during postharvest at 23ºC. Cold treatment, however, increased ABA levels and led to an inhibition of over-ripening. Furthermore, ABA levels positively correlated with anthocyanin and vitamin E levels during preharvest, but not during postharvest. We conclude that ABA plays a major role in sweet cherry development, stimulating its ripening process and positively influencing quality parameters during preharvest. The possible influence of ABA preventing over-ripening in cold-stored sweet cherries is also discussed.

  20. Implication of Abscisic Acid on Ripening and Quality in Sweet Cherries: Differential Effects during Pre- and Post-harvest.

    Tijero, Verónica; Teribia, Natalia; Muñoz, Paula; Munné-Bosch, Sergi

    2016-01-01

    Sweet cherry, a non-climacteric fruit, is usually cold-stored during post-harvest to prevent over-ripening. The aim of the study was to evaluate the role of abscisic acid (ABA) on fruit growth and ripening of this fruit, considering as well its putative implication in over-ripening and effects on quality. We measured the endogenous concentrations of ABA during the ripening of sweet cherries (Prunus avium L. var. Prime Giant) collected from orchard trees and in cherries exposed to 4°C and 23°C during 10 days of post-harvest. Furthermore, we examined to what extent endogenous ABA concentrations were related to quality parameters, such as fruit biomass, anthocyanin accumulation and levels of vitamins C and E. Endogenous concentrations of ABA in fruits increased progressively during fruit growth and ripening on the tree, to decrease later during post-harvest at 23°C. Cold treatment, however, increased ABA levels and led to an inhibition of over-ripening. Furthermore, ABA levels positively correlated with anthocyanin and vitamin E levels during pre-harvest, but not during post-harvest. We conclude that ABA plays a major role in sweet cherry development, stimulating its ripening process and positively influencing quality parameters during pre-harvest. The possible influence of ABA preventing over-ripening in cold-stored sweet cherries is also discussed. PMID:27200070

  1. Abscisic acid as an internal integrator of multiple physiological processes modulates leaf senescence onset in Arabidopsis thaliana

    Yuwei eSong

    2016-02-01

    Full Text Available Many studies have shown that exogenous abscisic acid (ABA promotes leaf abscission and senescence. However, owing to a lack of genetic evidence, ABA function in plant senescence has not been clearly defined. Here, two-leaf early-senescence mutants (eas that were screened by chlorophyll fluorescence imaging and named eas1-1 and eas1-2 showed high photosynthetic capacity in the early stage of plant growth compared with the wild type. Gene mapping showed that eas1-1 and eas1-2 are two novel ABA2 allelic mutants. Under unstressed conditions, the eas1 mutations caused plant dwarf, early germination, larger stomatal apertures, and early leaf senescence compared with those of the wild type. Flow cytometry assays showed that the cell apoptosis rate in eas1 mutant leaves was higher than that of the wild type after day 30. A significant increase in the transcript levels of several senescence-associated genes, especially SAG12, was observed in eas1 mutant plants in the early stage of plant growth. More importantly, ABA-activated calcium channel activity in plasma membrane and induced the increase of cytoplasmic calcium concentration in guard cells are suppressed due to the mutation of EAS1. In contrast, the eas1 mutants lost chlorophyll and ion leakage significant faster than in the wild type under treatment with calcium channel blocker. Hence, our results indicate that endogenous ABA level is an important factor controlling the onset of leaf senescence through Ca2+ signaling.

  2. Meristem maintenance, auxin, jasmonic and abscisic acid pathways as a mechanism for phenotypic plasticity in Antirrhinum majus

    Weiss, Julia; Alcantud-Rodriguez, Raquel; Toksöz, Tugba; Egea-Cortines, Marcos

    2016-01-01

    Plants grow under climatic changing conditions that cause modifications in vegetative and reproductive development. The degree of changes in organ development i.e. its phenotypic plasticity seems to be determined by the organ identity and the type of environmental cue. We used intraspecific competition and found that Antirrhinum majus behaves as a decoupled species for lateral organ size and number. Crowding causes decreases in leaf size and increased leaf number whereas floral size is robust and floral number is reduced. Genes involved in shoot apical meristem maintenance like ROA and HIRZ, cell cycle (CYCD3a; CYCD3b, HISTONE H4) or organ polarity (GRAM) were not significantly downregulated under crowding conditions. A transcriptomic analysis of inflorescence meristems showed Gene Ontology enriched pathways upregulated including Jasmonic and Abscisic acid synthesis and or signalling. Genes involved in auxin synthesis such as AmTAR2 and signalling AmANT were not affected by crowding. In contrast, AmJAZ1, AmMYB21, AmOPCL1 and AmABA2 were significantly upregulated. Our work provides a mechanistic working hypothesis where a robust SAM and stable auxin signalling enables a homogeneous floral size while changes in JA and ABA signalling maybe responsible for the decreased leaf size and floral number. PMID:26804132

  3. Interaction between abscisic acid and nitric oxide in PB90-induced catharanthine biosynthesis of catharanthus roseus cell suspension cultures.

    Chen, Qian; Chen, Zunwei; Lu, Li; Jin, Haihong; Sun, Lina; Yu, Qin; Xu, Hongke; Yang, Fengxia; Fu, Mengna; Li, Shengchao; Wang, Huizhong; Xu, Maojun

    2013-01-01

    Elicitations are considered to be an important strategy to improve production of secondary metabolites of plant cell cultures. However, mechanisms responsible for the elicitor-induced production of secondary metabolites of plant cells have not yet been fully elucidated. Here, we report that treatment of Catharanthus roseus cell suspension cultures with PB90, a protein elicitor from Phytophthora boehmeriae, induced rapid increases of abscisic acid (ABA) and nitric oxide (NO), subsequently followed by the enhancement of catharanthine production and up-regulation of Str and Tdc, two important genes in catharanthine biosynthesis. PB90-induced catharanthine production and the gene expression were suppressed by the ABA inhibitor and NO scavenger respectively, showing that ABA and NO are essential for the elicitor-induced catharanthine biosynthesis. The relationship between ABA and NO in mediating catharanthine biosynthesis was further investigated. Treatment of the cells with ABA triggered NO accumulation and induced catharanthine production and up-regulation of Str and Tdc. ABA-induced catharanthine production and gene expressions were suppressed by the NO scavenger. Conversely, exogenous application of NO did not stimulate ABA generation and treatment with ABA inhibitor did not suppress NO-induced catharanthine production and gene expressions. Together, the results showed that both NO and ABA were involved in PB90-induced catharanthine biosynthesis of C. roseus cells. Furthermore, our data demonstrated that ABA acted upstream of NO in the signaling cascade leading to PB90-induced catharanthine biosynthesis of C. roseus cells. PMID:23554409

  4. Jasmonate signaling involves the abscisic acid receptor PYL4 to regulate metabolic reprogramming in Arabidopsis and tobacco

    Lackman, Petri; González-Guzmán, Miguel; Tilleman, Sofie; Carqueijeiro, Inês; Pérez, Amparo Cuéllar; Moses, Tessa; Seo, Mitsunori; Kanno, Yuri; Häkkinen, Suvi T.; Van Montagu, Marc C. E.; Thevelein, Johan M.; Maaheimo, Hannu; Oksman-Caldentey, Kirsi-Marja; Rodriguez, Pedro L.; Rischer, Heiko; Goossens, Alain

    2011-01-01

    The phytohormones jasmonates (JAs) constitute an important class of elicitors for many plant secondary metabolic pathways. However, JAs do not act independently but operate in complex networks with crosstalk to several other phytohormonal signaling pathways. Here, crosstalk was detected between the JA and abscisic acid (ABA) signaling pathways in the regulation of tobacco (Nicotiana tabacum) alkaloid biosynthesis. A tobacco gene from the PYR/PYL/RCAR family, NtPYL4, the expression of which is regulated by JAs, was found to encode a functional ABA receptor. NtPYL4 inhibited the type-2C protein phosphatases known to be key negative regulators of ABA signaling in an ABA-dependent manner. Overexpression of NtPYL4 in tobacco hairy roots caused a reprogramming of the cellular metabolism that resulted in a decreased alkaloid accumulation and conferred ABA sensitivity to the production of alkaloids. In contrast, the alkaloid biosynthetic pathway was not responsive to ABA in control tobacco roots. Functional analysis of the Arabidopsis (Arabidopsis thaliana) homologs of NtPYL4, PYL4 and PYL5, indicated that also in Arabidopsis altered PYL expression affected the JA response, both in terms of biomass and anthocyanin production. These findings define a connection between a component of the core ABA signaling pathway and the JA responses and contribute to the understanding of the role of JAs in balancing tradeoffs between growth and defense. PMID:21436041

  5. Influence of abscisic acid on growth, biomass and lipid yield of Scenedesmus quadricauda under nitrogen starved condition.

    Sulochana, Sujitha Balakrishnan; Arumugam, Muthu

    2016-08-01

    Scenedesmus quadricauda, accumulated more lipid but with a drastic reduction in biomass yield during nitrogen starvation. Abscisic acid (ABA) being a stress responsible hormone, its effect on growth and biomass with sustainable lipid yield during nitrogen depletion was studied. The result revealed that the ABA level shoots up at 24h (27.21pmol/L) during the onset of nitrogen starvation followed by a sharp decline. The external supplemented ABA showed a positive effect on growth pattern (38×10(6)cells/ml) at a lower concentration. The dry biomass yield is also increasing up to 2.1 fold compared to nitrogen deficient S. quadricauda. The lipid content sustains in 1 and 2μM concentration of ABA under nitrogen-deficient condition. The fatty acid composition of ABA treated S. quadricauda cultures with respect to nitrogen-starved cells showed 11.17% increment in saturated fatty acid content, the desired lipid composition for biofuel application. PMID:26949054

  6. Studies on the growth and indole-3-acetic acid and abscisic acid content of Zea mays seedlings grown in microgravity

    Schulze, A.; Jensen, P. J.; Desrosiers, M.; Buta, J. G.; Bandurski, R. S.

    1992-01-01

    Measurements were made of the fresh weight, dry weight, dry weight-fresh weight ratio, free and conjugated indole-3-acetic acid, and free and conjugated abscisic acid in seedlings of Zea mays grown in darkness in microgravity and on earth. Imbibition of the dry kernels was 17 h prior to launch. Growth was for 5 d at ambient orbiter temperature and at a chronic accelerational force of the order of 3 x 10(-5) times earth gravity. Weights and hormone content of the microgravity seedlings were, with minor exceptions, not statistically different from seedlings grown in normal gravity. The tissues of the shuttle-grown plants appeared normal and the seedlings differed only in the lack of orientation of roots and shoots. These findings, based upon 5 d of growth in microgravity, cannot be extrapolated to growth in microgravity for weeks, months, and years, as might occur on a space station. Nonetheless, it is encouraging, for prospects of bioregeneration of the atmosphere and food production in a space station, that no pronounced differences in the parameters measured were apparent during the 5 d of plant seedling growth in microgravity.

  7. Growth and graviresponsiveness of primary roots of Zea mays seedlings deficient in abscisic acid and gibberellic acid

    Moore, R.; Dickey, K.

    1985-01-01

    The objective of this research was to determine if gibberellic acid (GA) and/or abscisic acid (ABA) are necessary for graviresponsiveness by primary roots of Zea mays. To accomplish this objective we measured the growth and graviresponsiveness of primary roots of seedlings in which the synthesis of ABA and GA was inhibited collectively and individually by genetic and chemical means. Roots of seedlings treated with Fluridone (an inhibitor of ABA biosynthesis) and Ancymidol (an inhibitor of GA biosynthesis) were characterized by slower growth rates but not significantly different gravicultures as compared to untreated controls. Gravicurvatures of primary roots of d-5 mutants (having undetectable levels of GA) and vp-9 mutants (having undectable levels of ABA) were not significantly different from those of wild-type seedlings. Roots of seedlings in which the biosynthesis of ABA and GA was collectively inhibited were characterized by gravicurvatures not significantly different for those of controls. These results (1) indicate that drastic reductions in the amount of ABA and GA in Z. mays seedlings do not significantly alter root graviresponsiveness, (2) suggest that neither ABA nor GA is necessary for root gravicurvature, and (3) indicate that root gravicurvature is not necessarily proportional to root elongation.

  8. Graviresponsiveness and abscisic-acid content of roots of carotenoid-deficient mutants of Zea mays L

    Moore, R.; Smith, J. D.

    1985-01-01

    The abscisic-acid (ABA) content of roots of the carotenoid-deficient w-3, vp-5, and vp-7 mutants of Z. mays was analyzed using gas chromatography-mass spectrometry with an analysis sensitivity of 6 ng ABA g-1 fresh weight (FW). Roots of normal seedlings of the same lines were characterized by the following amounts of ABA (as ng ABA g-1 FW, +/- standard deviation): w-3, 279 +/- 43; vp-5, 237 +/- 26; vp-7, 338 +/- 61. We did not detect any ABA in roots of any of the mutants. Thus, the lack of carotenoids in these mutants correlated positively with the apparent absence of ABA. Primary roots of normal and mutant seedlings were positively gravitropic, with no significant differences in the curvatures of roots of normal as compared with mutant seedlings. These results indicate that ABA 1) is synthesized in maize roots via the carotenoid pathway, and 2) is not necessary for positive gravitropism by primary roots of Z. mays.

  9. Genetic interaction of two abscisic acid signaling regulators, HY5 and FIERY1, in mediating lateral root formation

    Chen, Hao

    2011-01-01

    Root architecture is continuously shaped in a manner that helps plants to better adapt to the environment. Gene regulation at the transcriptional or post-transcriptional levels largely controls this environmental response. Recently, RNA silencing has emerged as an important player in gene regulation and is involved in many aspects of plant development, including lateral root formation. In a recent study, we found that FIERY1, a bifunctional abiotic stress and abscisic acid (ABA) signaling regulator and an endogenous RNA silencing suppressor, mediates auxin response during lateral root formation in Arabidopsis. We proposed that FRY1 regulates lateral root development through its activity on adenosine 3,5-bisphosphate (PAP), a strong inhibitor of exoribonucleases (XRNs). Interestingly, some of the phenotypes of fry1, such as enhanced response to light in repressing hypocotyl elongation and hypersensitivity to ABA in lateral root growth, are opposite to those of another light- and ABA-signaling mutant, hy5. Here we analyzed the hy5 fry1 double mutant for root and hypocotyl growth. We found that the hy5 mutation can suppress the enhanced light sensitivity in fry1 hypocotyl elongation and restore the lateral root formation. The genetic interaction between HY5 and FRY1 indicates that HY5 and FRY1 may act in overlapping pathways that mediate light signaling and lateral root development. © 2011 Landes Bioscience.

  10. Eucalyptus ESTs involved in the production of 9-cis epoxycarotenoid dioxygenase, a regulatory enzyme of abscisic acid production

    Iraê A. Guerrini

    2005-01-01

    Full Text Available Abscisic acid (ABA regulates stress responses in plants, and genomic tools can help us to understand the mechanisms involved in that process. FAPESP, a Brazilian research foundation, in association with four private forestry companies, has established the FORESTs database (https://forests.esalq.usp.br. A search was carried out in the Eucalyptus expressed sequence tag database to find ESTs involved with 9-cis epoxycarotenoid dioxygenase (NCED, the regulatory enzyme for ABA biosynthesis, using the basic local BLAST alignment tool. We found four clusters (EGEZLV2206B11.g, EGJMWD2252H08.g, EGBFRT3107F10.g, and EGEQFB1200H10.g, which represent similar sequences of the gene that produces NCED. Data showed that the EGBFRT3107F10.g cluster was similar to the maize (Zea mays NCED enzyme, while EGEZLV2206B11.g and EGJMWD2252H08.g clusters were similar to the avocado (Persea americana NCED enzyme. All Eucalyptus clusters were expressed in several tissues, especially in flower buds, where ABA has a special participation during the floral development process.

  11. Effects of Exterior Abscisic Acid on Calcium Distribution of Mesophyll Cells and Calcium Concentration of Guard Cells in Maize Seedlings

    GUO Xiu-lin; MA Yuan-yuan; LIU Zi-hui; LIU Bin-hui

    2008-01-01

    In this study, the direct effects of exterior abscisic acid (ABA) on both calcium distribution of mesophyll cells and cytosolic calcium concentration of guard cells were examined. The distribution of Ca2+ localization were observed with calcium antimonate precipitate-electromicroscopic-cyto-chemical methods after treated with ABA and pretreated with ethylene glycol-bis-(2-aminoethylether)-N,N,N',N'-tetraacetic acid (EGTA), verapamil (Vp), and trifluoperazine (TFP). The laser scanning confocal microscopy was used to measure the cytosolic calcium concentrations of guard cells under different treatments. The results showed that the cytosolic Ca2+ concentration of mesophyll cells was induced to increase by ABA, but to decrease in both outside cell and the vacuoles within 10 min after treatments. The cytosolic calcium concentration of guard cells was increased gradually with the lag in treatment time. However, both EGTA and TFP could inverse those effects, indicating that the increase of cytosolic calcium induced by exterior ABA was mainly caused by calcium influx. The results also showed that calmodulin could influence both the calcium distribution of mesophyll cells and calcium concentration of guard cells. It shows that calmodulin participates in the process of ABA signal transduction, but the mechanism is not known as yet. The changes both calcium distribution of mesophyll cells and calcium concentration of guard cells further proved that the variations of cytosolic Ca2+ concentration induced by ABA were involved in the stomatal movements of maize seedlings.

  12. Abscisic acid content, transpiration, and stomatal conductance as related to leaf age in plants Xanthium strumarium L

    Raschke, K.; Zeevaart, J.A.D.

    1976-01-01

    Among the four uppermost leaves of greenhouse-grown plants of Xanthium strumarium L., the content of abscisic acid per unit fresh or dry weight was highest in the youngest leaf and decreased gradually with increasing age of the leaves. Expressed per leaf, the second youngest leaf was richest in ABA; the amount of ABA per leaf declined only slightly as the leaves expanded. Transpiration and stomatal conductance were negatively correlated with the ABA concentration in the leaves; the youngest leaf lost the least amount of water. This correlation was always very good if the youngest leaf was compared with the older leaves but not always good among the older leaves. Since stomatal sensitivity to exogenous (+-)-ABA was the same in leaves of all four age groups ABA may be in at least two compartments in the leaf, one of which is isolated from the guard cells. The ability to synthesize ABA in response to wilting or chilling was strongly expressed in young leaves and declined with leaf age. There was no difference between leaves in their content of the metabolites of ABA, phaseic, and dihydrophaseic acid, expressed per unit weight.

  13. Evidence for a universal pathway of abscisic acid biosynthesis in higher plants from sup 18 O incorporation patterns

    Zeevaart, J.A.D.; Heath, T.G.; Gage, D.A. (Michigan State University, East Lansing (USA))

    1989-12-01

    Previous labeling studies of abscisic acid (ABA) with {sup 18}O{sub 2} have been mainly conducted with water-stressed leaves. In this study, {sup 18}O incorporation into ABA of stressed leaves of various species was compared with {sup 18}O labeling of ABA of turgid leaves and of fruit tissue in different stages of ripening. In stressed leaves of all six species investigated, avocado (Persea americana), barley (Hordeum vulgare), bean (Phaseolus vulgaris), cocklebur (Xanthium strumarium), spinach (Spinacia oleracea), and tobacco (Nicotiana tabacum), {sup 18}O was most abundant in the carboxyl group, whereas incorporation of a second and third {sup 18}O in the oxygen atoms on the ring of ABA was much less prominent after 24 h in {sup 18}O{sub 2}. ABA from turgid bean leaves showed significant {sup 18}O incorporation, again with highest {sup 18}O enrichment in the carboxyl group. On the basis of {sup 18}O-labeling patterns observed in ABA from different tissues it is concluded that, despite variations in precusor pool sizes and intermediate turnover rates, there is a universal pathway of ABA biosynthesis in higher plants which involves cleavage of a larger precursor molecule, presumably an oxygenated carotenoid.

  14. Integrin-like Protein Is Involved in the Osmotic Stress-induced Abscisic Acid Biosynthesis in Arabidopsis thaliana

    Bing Lü; Feng Chen; Zhong-Hua Gong; Hong Xie; Jian-Sheng Liang

    2007-01-01

    We studied the perception of plant cells to osmotic stress that leads to the accumulation of abscisic acid (ABA) in stressed Arabidopsis thaliana L. cells. A significant difference was found between protoplasts and cells in terms of their responses to osmotic stress and ABA biosynthesis, implying that cell wall and/or cell wall-plasma membrane interaction are essential in identifying osmotic stress. Western blotting and immunofluorescence localization experiments, using polyclonal antibody against human integrin β1, revealed the existence of a protein similar to the integrin protein of animals in the suspension-cultured cells located in the plasma membrane fraction.Treatment with a synthetic pentapeptide, Gly-Arg-Gly-Asp-Ser (GRGDS), which contains an RGD domain and interacts specifically with integrin protein and thus blocks the cell wall-plasma membrane interaction, significantly inhibited osmotic stress-induced ABA biosynthesis in cells, but not in protoplasts. These results demonstrate that cell wall and/or cell wall-plasma membrane interaction mediated by integrin-like proteins played important roles in osmotic stress-induced ABA biosynthesis in Arabidopsis thaliana.

  15. Analysis of Global Expression Profiles of Arabidopsis Genes Under Abscisic Acid and H2O2 Applications

    Peng-Cheng Wang; Yan-Yan Du; Guo-Yong An; Yun Zhou; Chen Miao; Chun-Peng Song

    2006-01-01

    To gain insight into the coordination of gene expression profiles under abscisic acid (ABA) and H2O2 applications,global changes in gene expression in response to ABA and H2O2 in Arabidopsis seedlings were investigated using GeneChip (Santa Clara, CA, USA) arrays. Among over 24 000 genes present in the arrays, 459 transcripts were found to be significantly increased, whereas another 221 decreased following H2O2 treatment compared with control. Similar to treatment with H2O2, ABA treatment elevated the transcription of 391 genes and repressed that of 322 genes. One hundred and forty-three upregulated genes and 75 downregulated genes were shared between the two treatments and these genes were mainly involved in metabolism, signal transduction, transcription, defense, and resistance. Only two genes, which encode an APETALA2/dehydration-responsive element binding protein (AP2/DREBP) family transcriptional factor and a late embryogenesisabundant protein, were downregulated by H2O2, but upregulated by ABA. These results suggest that, similar to ABA, H2O2 plays a global role in gene transcription of Arabidopsisseedlings. The transcriptional responses induced by the application of exogenous ABA and H2O2 overlapped substantially. These two treatments regulated most of the downstream genes in a coordinated manner.

  16. Light-harvesting complexes in photosystem II regulate glutathione-induced sensitivity of Arabidopsis guard cells to abscisic acid.

    Jahan, Md Sarwar; Nozulaidi, Mohd; Khairi, Mohd; Mat, Nashriyah

    2016-05-20

    Light-harvesting complexes (LHCs) in photosystem II (PSII) regulate glutathione (GSH) functions in plants. To investigate whether LHCs control GSH biosynthesis that modifies guard cell abscisic acid (ABA) sensitivity, we evaluated GSH content, stomatal aperture, reactive oxygen species (ROS), weight loss and plant growth using a ch1-1 mutant that was defective of LHCs and compared this with wild-type (WT) Arabidopsis thaliana plants. Glutathione monoethyl ester (GSHmee) increased but 1-chloro-2,4 dinitrobenzene (CDNB) decreased the GSH content in the guard cells. The guard cells of the ch1-1 mutants accumulated significantly less GSH than the WT plants. The guard cells of the ch1-1 mutants also showed higher sensitivity to ABA than the WT plants. The CDNB treatment increased but the GSHmee treatment decreased the ABA sensitivity of the guard cells without affecting ABA-induced ROS production. Dark and light treatments altered the GSH content and stomatal aperture of the guard cells of ch1-1 and WT plants, irrespective of CDNB and GSHmee. The ch1-1 mutant contained fewer guard cells and displayed poor growth, late flowering and stumpy weight loss compared with the WT plants. This study suggests that defective LHCs reduced the GSH content in the guard cells and increased sensitivity to ABA, resulting in stomatal closure. PMID:26970687

  17. Evidence for a universal pathway of abscisic acid biosynthesis in higher plants from 18O incorporation patterns

    Previous labeling studies of abscisic acid (ABA) with 18O2 have been mainly conducted with water-stressed leaves. In this study, 18O incorporation into ABA of stressed leaves of various species was compared with 18O labeling of ABA of turgid leaves and of fruit tissue in different stages of ripening. In stressed leaves of all six species investigated, avocado (Persea americana), barley (Hordeum vulgare), bean (Phaseolus vulgaris), cocklebur (Xanthium strumarium), spinach (Spinacia oleracea), and tobacco (Nicotiana tabacum), 18O was most abundant in the carboxyl group, whereas incorporation of a second and third 18O in the oxygen atoms on the ring of ABA was much less prominent after 24 h in 18O2. ABA from turgid bean leaves showed significant 18O incorporation, again with highest 18O enrichment in the carboxyl group. On the basis of 18O-labeling patterns observed in ABA from different tissues it is concluded that, despite variations in precusor pool sizes and intermediate turnover rates, there is a universal pathway of ABA biosynthesis in higher plants which involves cleavage of a larger precursor molecule, presumably an oxygenated carotenoid

  18. Overexpression of OsWRKY72 gene interferes in the abscisic acid signal and auxin transport pathway of Arabidopsis

    Song Yu; Chen Ligang; Zhang Liping; Yu Diqiu

    2010-09-01

    Through activating specific transcriptional programmes, plants can launch resistance mechanisms to stressful environments and acquire a new equilibrium between development and defence. To screen the rice WRKY transcription factor which functions in abiotic stress tolerance and modulates the abscisic acid (ABA) response, we generated a whole array of 35S-OsWRKY transgenic Arabidopsis. In this study, we report that 35S-OsWRKY72 transgenic Arabidopsis, whose seed germination was retarded under normal conditions, emerged more sensitive to mannitol, NaCl, ABA stresses and sugar starvation than vector plants. Meanwhile, 35S-OsWRKY72 transgenic Arabidopsis displayed early flowering, reduced apical dominance, lost high temperature-induced hypocotyl elongation response, and enhanced gravitropism response, which were similar to the auxin-related gene mutants aux1, axr1 and bud1. Further, semi-quantitative RT-PCR showed that the expression patterns of three auxin-related genes AUX1, AXR1 and BUD1 were significantly altered in rosette leaves and inflorescences of 35S-OsWRKY72 plants compared with control Arabidopsis, and two ABA-related genes ABA2 and ABI4 were induced in 35S-OsWRKY72 seedlings. In addition, northern blot analysis indicated that, in rice, OsWRKY72 was inducible by polyethylene glycol (PEG), NaCl, naphthalene acetic acid (NAA), ABA and 42°C, similar to its orthologue AtWRKY75 in Arabidopsis, implying that these two WRKY genes might be required for multiple physiological processes in their plants. Together, these results suggest that OsWRKY72 interferes in the signal cross-talk between the ABA signal and auxin transport pathway in transgenic Arabidopsis.

  19. Effects of abscisic acid and high osmoticum on storage protein gene expression in microspore embryos of Brassica napus

    Storage protein gene expression, characteristic of mid- to late embryogenesis, was investigated in microspore embryos of rapeseed (Brassica napus). These embryos, derived from the immature male gametophyte, accumulate little or no detectable napin or cruciferin mRNA when cultured on hormone-free medium containing 13% sucrose. The addition of abscisic acid (ABA) to the medium results in an increase in detectable transcripts encoding both these polypeptides. Storage protein mRNA is induced at 1 micromolar ABA with maximum stimulation occurring between 5 and 50 micromolar. This hormone induction results in a level of storage protein mRNA that is comparable to that observed in zygotic embryos of an equivalent morphological stage. Effects similar to that of ABA are noted when 12.5% sorbitol is added to the microspore embryo medium (osmotic potential = 25.5 bars). Time course experiments, to study the induction of napin and cruciferin gene expression demonstrated that the ABA effect occurred much more rapidly than the high osmoticum effect, although after 48 hours, the levels of napin or cruciferin mRNA detected were similar in both treatments. This difference in the rates of induction is consistent with the idea that the osmotic effect may be mediated by ABA which is synthesized in response to the reduced water potential. Measurements of ABA (by gas chromatography-mass spectrometry using [2H6]ABA as an internal standard) present in microspore embryos during sorbitol treatment and in embryos treated with 10 micromolar ABA were performed to investigate this possibility. Within 2 hours of culture on high osmoticum the level of ABA increased substantially and significantly above control and reached a maximum concentration within 24 hours. This elevated concentration was maintained for 48 hours after culturing and represents a sixfold increase over control embryos

  20. Abscisic acid, a stress hormone helps in improving water relations and yield of sunflower (helianthus annuus l.) hybrids under drought

    Genotypic variation in water relations under drought is an important index of studying drought tolerance of crops. Abscisic acid (ABA) application helped in mitigating drought stress by improving water relations and yield. Three sunflower hybrids viz., DK-4040 (tall stature), S-278 (medium stature) and SF-187 (short stature) were subjected to different irrigation and ABA application regimes i.e., four irrigations (25 days after sowing (DAS), at bud initiation, at flower initiation and at achene formation) and with no ABA spray, three irrigations (25 days after sowing, at flower initiation and at achene formation) and with no ABA spray, three irrigations (25 days after sowing, at flower initiation and at achene formation) and with ABA spray at bud initiation, three irrigations (25 days after sowing), at bud initiation and at achene formation) and with no ABA spray, three irrigations (25 days after sowing), at bud initiation and at achene formation) and with ABA spray at flower initiation. The experiment was laid out in randomized complete block design with split plot arrangement and had three replications. Exogenous application of ABA under drought at either stage (bud or flower initiation) was helpful in ameliorating drought stress by improving water relations and yield of sunflower hybrids; however response was better when ABA was applied under drought at bud initiation than at flower initiation stage. Sunflower hybrid DK- 4040 showed better enhancement of drought tolerance by exogenous application of ABA under drought than SF-187 and S-278 because it showed more improvement in water potential, osmotic potential, turgor pressure, relative leaf water contents and achene yield. (author)

  1. Structural basis for basal activity and autoactivation of abscisic acid (ABA) signaling SnRK2 kinases

    Ng, Ley-Moy; Soon, Fen-Fen; Zhou, X. Edward; West, Graham M.; Kovach, Amanda; Suino-Powell, Kelly M.; Chalmers, Michael J.; Li, Jun; Yong, Eu-Leong; Zhu, Jian-Kang; Griffin, Patrick R.; Melcher, Karsten; Xu, H. Eric (Van Andel); (Scripps); (Purdue); (NU Singapore)

    2014-10-02

    Abscisic acid (ABA) is an essential hormone that controls plant growth, development, and responses to abiotic stresses. Central for ABA signaling is the ABA-mediated autoactivation of three monomeric Snf1-related kinases (SnRK2.2, -2.3, and -2.6). In the absence of ABA, SnRK2s are kept in an inactive state by forming physical complexes with type 2C protein phosphatases (PP2Cs). Upon relief of this inhibition, SnRK2 kinases can autoactivate through unknown mechanisms. Here, we report the crystal structures of full-length Arabidopsis thaliana SnRK2.3 and SnRK2.6 at 1.9- and 2.3-{angstrom} resolution, respectively. The structures, in combination with biochemical studies, reveal a two-step mechanism of intramolecular kinase activation that resembles the intermolecular activation of cyclin-dependent kinases. First, release of inhibition by PP2C allows the SnRK2s to become partially active because of an intramolecular stabilization of the catalytic domain by a conserved helix in the kinase regulatory domain. This stabilization enables SnRK2s to gain full activity by activation loop autophosphorylation. Autophosphorylation is more efficient in SnRK2.6, which has higher stability than SnRK2.3 and has well-structured activation loop phosphate acceptor sites that are positioned next to the catalytic site. Together, these data provide a structural framework that links ABA-mediated release of PP2C inhibition to activation of SnRK2 kinases.

  2. Foliar abscisic acid-to-ethylene accumulation and response regulate shoot growth sensitivity to mild drought in wheat

    Ravi eValluru

    2016-04-01

    Full Text Available Although plant hormones play an important role in adjusting growth in response to environmental perturbation, the relative contributions of abscisic acid (ABA and ethylene remain elusive. Using six spring wheat genotypes differing for stress tolerance, we show that young seedlings of the drought-tolerant (DT group maintained or increased shoot dry weight (SDW while the drought-susceptible (DS group decreased SDW in response to mild drought. Both the DT and DS groups increased endogenous ABA and ethylene concentrations under mild drought compared to control. The DT and DS groups exhibited different SDW response trends, whereby the DS group decreased while the DT group increased SDW, to increased concentrations of ABA and ethylene under mild drought, although both groups decreased ABA/ethylene ratio under mild drought albeit at different levels. We concluded that SDW of the DT and DS groups might be distinctly regulated by specific ABA:ethylene ratio. Further, a foliar-spray of low concentrations (0.1 μM of ABA increased shoot relative growth rate (RGR in the DS group while ACC (1-aminocyclopropane-1-carboxylic acid, ethylene precursor spray increased RGR in both groups compared to control. Furthermore, the DT group accumulated a significantly higher galactose while a significantly lower maltose in the shoot compared to the DS group. Taken all together, these results suggest an impact of ABA, ethylene and ABA:ethylene ratio on SDW of wheat seedlings that may partly underlie a genotypic variability of different shoot growth sensitivities to drought among crop species under field conditions. We propose that phenotyping based on hormone accumulation, response and hormonal ratio would be a viable, rapid, and an early–stage selection tool aiding genotype selection for stress tolerance.

  3. Arabidopsis plastid AMOS1/EGY1 integrates abscisic acid signaling to regulate global gene expression response to ammonium stress

    Li, Baohai

    2012-10-12

    Ammonium (NH4 +) is a ubiquitous intermediate of nitrogen metabolism but is notorious for its toxic effects on most organisms. Extensive studies of the underlying mechanisms of NH4 + toxicity have been reported in plants, but it is poorly understood how plants acclimate to high levels of NH4 +. Here, we identified an Arabidopsis (Arabidopsis thaliana) mutant, ammonium overly sensitive1 (amos1), that displays severe chlorosis under NH4 + stress. Map-based cloning shows amos1 to carry a mutation in EGY1 (for ethylene-dependent, gravitropism-deficient, and yellow-green-like protein1), which encodes a plastid metalloprotease. Transcriptomic analysis reveals that among the genes activated in response to NH4 +, 90% are regulated dependent on AMOS1/ EGY1. Furthermore, 63% of AMOS1/EGY1-dependent NH4 +-activated genes contain an ACGTG motif in their promoter region, a core motif of abscisic acid (ABA)-responsive elements. Consistent with this, our physiological, pharmacological, transcriptomic, and genetic data show that ABA signaling is a critical, but not the sole, downstream component of the AMOS1/EGY1-dependent pathway that regulates the expression of NH4 +-responsive genes and maintains chloroplast functionality under NH4 + stress. Importantly, abi4 mutants defective in ABA-dependent and retrograde signaling, but not ABA-deficient mutants, mimic leaf NH4 + hypersensitivity of amos1. In summary, our findings suggest that an NH4 +-responsive plastid retrograde pathway, which depends on AMOS1/EGY1 function and integrates with ABA signaling, is required for the regulation of expression of the presence of high NH4 + levels. © 2012 American Society of Plant Biologists. All Rights Reserved.

  4. Foliar Abscisic Acid-To-Ethylene Accumulation and Response Regulate Shoot Growth Sensitivity to Mild Drought in Wheat.

    Valluru, Ravi; Davies, William J; Reynolds, Matthew P; Dodd, Ian C

    2016-01-01

    Although, plant hormones play an important role in adjusting growth in response to environmental perturbation, the relative contributions of abscisic acid (ABA) and ethylene remain elusive. Using six spring wheat genotypes differing for stress tolerance, we show that young seedlings of the drought-tolerant (DT) group maintained or increased shoot dry weight (SDW) while the drought-susceptible (DS) group decreased SDW in response to mild drought. Both the DT and DS groups increased endogenous ABA and ethylene concentrations under mild drought compared to control. The DT and DS groups exhibited different SDW response trends, whereby the DS group decreased while the DT group increased SDW, to increased concentrations of ABA and ethylene under mild drought, although both groups decreased ABA/ethylene ratio under mild drought albeit at different levels. We concluded that SDW of the DT and DS groups might be distinctly regulated by specific ABA:ethylene ratio. Further, a foliar-spray of low concentrations (0.1 μM) of ABA increased shoot relative growth rate (RGR) in the DS group while ACC (1-aminocyclopropane-1-carboxylic acid, ethylene precursor) spray increased RGR in both groups compared to control. Furthermore, the DT group accumulated a significantly higher galactose while a significantly lower maltose in the shoot compared to the DS group. Taken all together, these results suggest an impact of ABA, ethylene, and ABA:ethylene ratio on SDW of wheat seedlings that may partly underlie a genotypic variability of different shoot growth sensitivities to drought among crop species under field conditions. We propose that phenotyping based on hormone accumulation, response and hormonal ratio would be a viable, rapid, and an early-stage selection tool aiding genotype selection for stress tolerance. PMID:27148292

  5. Abscisic acid activates a Ca2+-calmodulin-stimulated protein kinase involved in antioxidant defense in maize leaves

    Shucheng Xu

    2010-01-01

     The role of a calcium-dependent and calmodulin(CaM)stimulated protein kinase in abscisic acid(ABA)-induced antioxidant defense was determined in leaves of maize (Zea mays).In-gel kinase assays showed that treatments with ABA or H2O2 induced the activation of a 49-kDa protein kinase and a 52-kDa protein kinase significantly.Furthermore,we showed that the 52-kDa protein kinase has the characteristics of CaM-stimulating activity and is sensitive to calcium-CaM-dependent protein kinase Ⅱ (CaMK Ⅱ)inhibitor KN-93 or CaM antagonist W-7.Treatments with ABA or H2O2 not only induced the acti vation of the 52-kDa protein kinase,but also enhanced the total activities of the antioxidant enzymes,including catalase,ascorbate peroxidase,glutathione reductase,and superoxide dismutase.Such enhancements were blocked by pretreatment with a CaMK inhibitor and a reactive oxygen species(ROS)inhibitor or scavenger.Pretreatment with the CaMK inhibitor also substantially arrested the ABA-induced H2O2 production.Kinase activity enhancements induced by ABA were attenuated by pretreatment with an ROS inhibitor or scavenger.These results suggest that the 52-kDa CaMK is involved in ABA-induced antioxidant defense and that cross-talk between CaMK and H2O2 plays a pivotal role in ABA signaling.We infer that CaMK acts both upstream and downstream of H2O2,but mainly acts between ABA and H2O2 in ABA-induced antioxidant-defensive signaling.

  6. Genome-Wide Analysis of MicroRNA Responses to the Phytohormone Abscisic Acid in Populus euphratica.

    Duan, Hui; Lu, Xin; Lian, Conglong; An, Yi; Xia, Xinli; Yin, Weilun

    2016-01-01

    MicroRNA (miRNA) is a type of non-coding small RNA with a regulatory function at the posttranscriptional level in plant growth development and in response to abiotic stress. Previous studies have not reported on miRNAs responses to the phytohormone abscisic acid (ABA) at a genome-wide level in Populus euphratica, a model tree for studying abiotic stress responses in woody plants. Here we analyzed the miRNA response to ABA at a genome-wide level in P. euphratica utilizing high-throughput sequencing. To systematically perform a genome-wide analysis of ABA-responsive miRNAs in P. euphratica, nine sRNA libraries derived from three groups (control, treated with ABA for 1 day and treated with ABA for 4 days) were constructed. Each group included three libraries from three individual plantlets as biological replicate. In total, 151 unique mature sequences belonging to 75 conserved miRNA families were identified, and 94 unique sequences were determined to be novel miRNAs, including 56 miRNAs with miRNA(*) sequences. In all, 31 conserved miRNAs and 31 novel miRNAs response to ABA significantly differed among the groups. In addition, 4132 target genes were predicted for the conserved and novel miRNAs. Confirmed by real-time qPCR, expression changes of miRNAs were inversely correlated with the expression profiles of their putative targets. The Populus special or novel miRNA-target interactions were predicted might be involved in some biological process related stress tolerance. Our analysis provides a comprehensive view of how P. euphratica miRNA respond to ABA, and moreover, different temporal dynamics were observed in different ABA-treated libraries. PMID:27582743

  7. Ectopic expression of ABSCISIC ACID 2/GLUCOSE INSENSITIVE 1 in Arabidopsis promotes seed dormancy and stress tolerance.

    Lin, Pei-Chi; Hwang, San-Gwang; Endo, Akira; Okamoto, Masanori; Koshiba, Tomokazu; Cheng, Wan-Hsing

    2007-02-01

    Abscisic acid (ABA) is an important phytohormone that plays a critical role in seed development, dormancy, and stress tolerance. 9-cis-Epoxycarotenoid dioxygenase is the key enzyme controlling ABA biosynthesis and stress tolerance. In this study, we investigated the effect of ectopic expression of another ABA biosynthesis gene, ABA2 (or GLUCOSE INSENSITIVE 1 [GIN1]) encoding a short-chain dehydrogenase/reductase in Arabidopsis (Arabidopsis thaliana). We show that ABA2-overexpressing transgenic plants with elevated ABA levels exhibited seed germination delay and more tolerance to salinity than wild type when grown on agar plates and/or in soil. However, the germination delay was abolished in transgenic plants showing ABA levels over 2-fold higher than that of wild type grown on 250 mm NaCl. The data suggest that there are distinct mechanisms underlying ABA-mediated inhibition of seed germination under diverse stress. The ABA-deficient mutant aba2, with a shorter primary root, can be restored to normal root growth by exogenous application of ABA, whereas transgenic plants overexpressing ABA2 showed normal root growth. The data reflect that the basal levels of ABA are essential for maintaining normal primary root elongation. Furthermore, analysis of ABA2 promoter activity with ABA2::beta-glucuronidase transgenic plants revealed that the promoter activity was enhanced by multiple prolonged stresses, such as drought, salinity, cold, and flooding, but not by short-term stress treatments. Coincidently, prolonged drought stress treatment led to the up-regulation of ABA biosynthetic and sugar-related genes. Thus, the data support ABA2 as a late expression gene that might have a fine-tuning function in mediating ABA biosynthesis through primary metabolic changes in response to stress. PMID:17189333

  8. Translation initiation factor 5A in Picrorhiza is up-regulated during leaf senescence and in response to abscisic acid.

    Parkash, Jai; Vaidya, Tanmay; Kirti, Shruti; Dutt, Som

    2014-05-25

    Translation initiation, the first step of protein synthesis process is the principal regulatory step controlling translation and involves a pool of translation initiation factors. In plants, from recent studies it is becoming evident that these translation initiation factors impact various aspects of plant growth and development in addition to their role in protein synthesis. Eukaryotic translation initiation factor eIF5A is one such factor which functions in start site selection for the eIF2-GTP-tRNAi ternary complex within the ribosomal-bound preinitiation complex and also stabilizes the binding of GDP to eIF2. In the present study we have cloned and analysed a gene (eIF5a) encoding eIF5A from Picrorhiza (Picrorhiza kurrooa Royle ex Benth.) a medicinal plant of the western Himalayan region. The full length eIF5a cDNA consisted of 838 bp with an open reading frame of 480 bp, 88 bp 5' untranslated region and 270 bp 3' untranslated region. The deduced eIF5A protein contained 159 amino acids with a molecular weight of 17.359 kDa and an isoelectric point of 5.59. Secondary structure analysis revealed eIF5A having 24.53% α-helices, 8.81% β-turns, 23.27% extended strands and 43.40% random coils. pk-eIF5a transcript was found to be expressing during the active growth phase as well as during leaf senescence stage, however, highest expression was observed during leaf senescence stage. Further, its expression was up-regulated in response to exogenous application of abscisic acid. Both high intensity as well as low intensity light decreased the expression of pk-eIF5a. The findings suggest eIF5a to be an important candidate to develop genetic engineering based strategies for delaying leaf senescence. PMID:24656625

  9. ZmABA2, an interacting protein of ZmMPK5, is involved in abscisic acid biosynthesis and functions.

    Ma, Fangfang; Ni, Lan; Liu, Libo; Li, Xi; Zhang, Huan; Zhang, Aying; Tan, Mingpu; Jiang, Mingyi

    2016-02-01

    In maize (Zea mays), the mitogen-activated protein kinase ZmMPK5 has been shown to be involved in abscisic acid (ABA)-induced antioxidant defence and to enhance the tolerance of plants to drought, salt stress and oxidative stress. However, the underlying molecular mechanisms are poorly understood. Here, using ZmMPK5 as bait in yeast two-hybrid screening, a protein interacting with ZmMPK5 named ZmABA2, which belongs to a member of the short-chain dehydrogenase/reductase family, was identified. Pull-down assay and bimolecular fluorescence complementation analysis and co-immunoprecipitation test confirmed that ZmMPK5 interacts with ZmABA2 in vitro and in vivo. Phosphorylation of Ser173 in ZmABA2 by ZmMPK5 was shown to increase the activity of ZmABA2 and the protein stability. Various abiotic stimuli induced the expression of ZmABA2 in leaves of maize plants. Pharmacological, biochemical and molecular biology and genetic analyses showed that both ZmMPK5 and ZmABA2 coordinately regulate the content of ABA. Overexpression of ZmABA2 in tobacco plants was found to elevate the content of ABA, regulate seed germination and root growth under drought and salt stress and enhance the tolerance of tobacco plants to drought and salt stress. These results suggest that ZmABA2 is a direct target of ZmMPK5 and is involved in ABA biosynthesis and functions. PMID:26096642

  10. Abscisic acid refines the synthesis of chloroplast proteins in maize (Zea mays in response to drought and light.

    Xiuli Hu

    Full Text Available To better understand abscisic acid (ABA regulation of the synthesis of chloroplast proteins in maize (Zea mays L. in response to drought and light, we compared leaf proteome differences between maize ABA-deficient mutant vp5 and corresponding wild-type Vp5 green and etiolated seedlings exposed to drought stress. Proteins extracted from the leaves of Vp5 and vp5 seedlings were used for two-dimensional electrophoresis (2-DE and subsequent matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF mass spectrometry (MS. After Coomassie brilliant blue staining, approximately 450 protein spots were reproducibly detected on 2-DE gels. A total of 36 differentially expressed protein spots in response to drought and light were identified using MALDI-TOF MS and their subcellular localization was determined based on the annotation of reviewed accession in UniProt Knowledgebase and the software prediction. As a result, corresponding 13 proteins of the 24 differentially expressed protein spots were definitely localized in chloroplasts and their expression was in an ABA-dependent way, including 6 up-regulated by both drought and light, 5 up-regulated by drought but down-regulated by light, 5 up-regulated by light but down-regulated by drought; 5 proteins down-regulated by drought were mainly those involved in photosynthesis and ATP synthesis. Thus, the results in the present study supported the vital role of ABA in regulating the synthesis of drought- and/or light-induced proteins in maize chloroplasts and would facilitate the functional characterization of ABA-induced chloroplast proteins in C(4 plants.

  11. Cross-talk between calcium-calmodulin and nitric oxide in abscisic acid signaling in leaves of maize plants

    Jianrong Sang; Aying Zhang; Fan Lin; Mingpu Tan; Mingyi Jiang

    2008-01-01

    Using pharmacological and biochemical approaches,the signaling pathways between hydrogen peroxide (H2O2),calcium (Ca2+)-calmodulin (CAM),and nitric oxide (NO) in abscisic acid (ABA)-induced antioxidant defense were investigated in leaves of maize (Zea mays L.) plants.Treatments with ABA,H2O2,and CaCI2 induced increases in the generation of NO in maize mesophyll cells and the activity of nitric oxide synthase (NOS) in the cytosolic and microsomal fractions of maize leaves.However,such increases were blocked by the pretreatments with Ca2+ inhibitors and CaM antagonists.Meanwhile,pretreatments with two NOS inhibitors also suppressed the Ca2+-induced increase in the production of NO.On the other hand,treatments with ABA and the NO donor sodium nitroprusside (SNP) also led to increases in the concentration of cytosolic Ca2+ in protoplasts of mesophyll cells and in the expression of calmodulin 1 (CaMI) gene and the contents of CaM in leaves of maize plants,and the increases induced by ABA were reduced by the pretreatments with a NO scavenger and a NOS inhibitor.Moreover,SNP-induced increases in the expression of the antioxidant genes superoxide dismutase 4 (SOD4),cytosolic ascorbate peroxidase (cAPX),and glutathione reductase 1 (GRI) and the activities of the chloroplastic and cytosolic antioxidant enzymes were arrested by the pretreatments with Ca2+ inhibitors and CaM antagonists.Our results suggest that Ca2+-CaM functions both upstream and downstream of NO production,which is mainly from NOS,in ABA- and H2O2-induced antioxidant defense in leaves of maize plants.

  12. Effect of Abscisic Acid and Polyethylene Glycol on the Synchronization of Somatic Embryo Development in Date Palm (Phoenix dactylifera L.

    Abdulaziz M. Al-Bahrany

    2012-01-01

    Full Text Available Somatic embryogenesis provides the best method for commercial micropropagation of date palm (Phoenix dactylifera L.; however, a current limitation is the lack of synchronization of developing somatic embryos. The objective of this study was to evaluate the effect of Abscisic Acid (ABA and polyethylene glycol (PEG combinations on the synchronization of embryo development in date palm cell suspension. Callus maintained on MS medium containing 54 μM Naphthalene Acetic Acid (NAA and 7 μM 2-isopentenyladenine (2iP was transferred to regeneration liquid medium supplemented with ABA at 0-100 μM and PEG at 0-15%. Maximum fresh culture weight was obtained with 10% PEG in the absence of ABA. The addition of as low as 1 μM ABA to the suspensions inhibited growth. In the absence of ABA, increasing PEG concentration increased total somatic embryo numbers reaching a maximum number at 10% PEG. Various embryo sizes differing in abundance were associated with different treatments. The highest percentage of medium size embryos, 52%, was obtained at 10 μM ABA; whereas, the highest percentage of small embryos was obtained at 50-100 μM ABA. The small embryos exhibited a state of synchronization. Although, treating suspensions with ABA and PEG affected embryo size distribution, germination was influenced by embryo developmental phase, expressed in size. Germination of 43, 63, 52 and 23% was obtained from the small, medium, large and very large embryos, respectively. Retardation of somatic embryo development caused by ABA can be further exploited to optimize culture synchronization.

  13. Abscisic acid enhances tolerance of wheat seedlings to drought and regulates transcript levels of genes encoding ascorbate-glutathione biosynthesis.

    Wei, Liting; Wang, Lina; Yang, Yang; Wang, Pengfei; Guo, Tiancai; Kang, Guozhang

    2015-01-01

    Glutathione (GSH) and ascorbate (ASA) are associated with the abscisic acid (ABA)-induced abiotic tolerance in higher plant, however, its molecular mechanism remains obscure. In this study, exogenous application (10 μM) of ABA significantly increased the tolerance of seedlings of common wheat (Triticum aestivum L.) suffering from 5 days of 15% polyethylene glycol (PEG)-stimulated drought stress, as demonstrated by increased shoot lengths and shoot and root dry weights, while showing decreased content of hydrogen peroxide (H2O2) and malondialdehyde (MDA). Under drought stress conditions, ABA markedly increased content of GSH and ASA in both leaves and roots of ABA-treated plants. Temporal and spatial expression patterns of eight genes encoding ASA and GSH synthesis-related enzymes were measured using quantitative real-time reverse transcription polymerase chain reaction (qPCR). The results showed that ABA temporally regulated the transcript levels of genes encoding ASA-GSH cycle enzymes. Moreover, these genes exhibited differential expression patterns between the root and leaf organs of ABA-treated wheat seedlings during drought stress. These results implied that exogenous ABA increased the levels of GSH and ASA in drought-stressed wheat seedlings in time- and organ-specific manners. Moreover, the transcriptional profiles of ASA-GSH synthesis-related enzyme genes in the leaf tissue were compared between ABA- and salicylic acid (SA)-treated wheat seedlings under PEG-stimulated drought stress, suggesting that they increased the content of ASA and GSH by differentially regulating expression levels of ASA-GSH synthesis enzyme genes. Our results increase our understanding of the molecular mechanism of ABA-induced drought tolerance in higher plants. PMID:26175737

  14. Genetic effects in callose content in root apex of inbred resistant and susceptible corn lines to acid soils Efectos genéticos de la formación de calosa en ápices radicales de líneas de maíz resistentes y susceptibles a suelos ácidos

    Arcos Alba Lucía

    2007-12-01

    Full Text Available

    The main objective of this work was to identify genetic parameters that are related to callose accumulation using tropical inbreeds corn. Fourteen inbreed lines selected for different levels of tolerance to acid soils were chosen and a diallel among them was generated. The seeds were grown under controlled environmental conditions in a growth chamber and transferred to a nutrient solution at pH 4.3. After 12 hours of 25 µM Al (AlCl3 treatment was applied, callose contents of 1 cm root apex were determined with fluorescence spectrophotometer. Significant differences were found for parents, crosses and parents vs crosses. Average callose content varied from 0.746 to 2.035 (µg PE/cm root apex. Heterosis varied from –21.2% to 276.3%. General combining ability (GCA and specific combining ability (SCA were highly significant indicating that both, additive and non–additive gene effects were important for callose inheritance. SCA and GCA sum of squares accounted for 54% and 46%, respectively of crosses of squares sum. Correlation coefficient between callose content and corn grain yield in the field was negative but not significant (r = –0.38.

    Key words: Zea mays; callose; inheritance; diallel; heterosis; acid soils.

    El objetivo de este trabajo fue estudiar la herencia de la producción de calosa utilizando líneas endogámicas de maíz. Seleccionando 14 líneas (7 tolerantes y 7 susceptibles a suelos ácidos se formó un dialelo que fue probado en campo y en invernadero. Se determinó el contenido de calosa en los 91 cruzamientos resultantes y los 14 progenitores. Para ello se colocaron las semillas en cámara de crecimiento en condiciones controladas. Después de 4–5 días las plántulas fueron transferidas a cubetas que contenían solución nutritiva con aireación constante. Luego de 48 horas se adicionaron 25 µM de aluminio (AlCl3 a cada una de las cubetas y se mantuvieron por 12 horas. Se cortaron tres ápices radicales de

  15. Distinctive patterns of callose deposition provide an early sign of ovule abortion1 in the andromonoecious shrub Caesalpinia gilliesii Patrones distintivos de deposición de calosa proveen evidencia temprana de aborto de óvulos en el arbusto andromonoico Caesalpinia gilliesii

    A. Calviño

    2009-07-01

    Full Text Available Ovule abortion may lead to the partial or complete reduction of the number of functional ovules in the ovary and then is the primary factor that determines the sexual expression of the plant. In different species, ovule abortion was associated with the presence of callose in advanced ovules. Based on these observations, we studied the pattern of ovule development and callose deposition in both perfect and staminate flowers of the andromonoecious shrub Caesalpinia gilliesii. The obtained results showed that all ovules reached the 8-nucleate stage of embryo sac development and exhibited callose deposition at advanced stages. Nevertheless, from the 2-nucleate stage, a distinct spatial pattern of callose deposition within the ovule was observed between perfect and staminate flowers. Differences in callose deposition suggest that not callose per se but its distribution pattern in the ovule tissues is the main factor that triggers ovule isolation and abortion and leads to flowers with non-functional pistils in this species. Furthermore, previous observed differential growth rates between perfect and staminate flowers support for resource depletion as the likely underlying mechanism of ovule fate in C. gilliesii.El aborto de óvulos puede llevar a la reducción parcial o completa de óvulos fértiles en el ovario, pudiendo ser entonces un factor primario que determine la expresión sexual de toda la planta. En diferentes especies de plantas, el aborto de los óvulos ha sido asociado con la presencia de calosa en estadios avanzados del desarrollo de los óvulos. Basado en estas observaciones, se estudiaron el desarrollo de los óvulos y el patrón de deposición de calosa tanto en flores perfectas como estaminadas en el arbusto andromonoico C. gilliesii. Los resultados obtenidos muestran que los sacos embrionarios alcanzan el estadio de desarrollo 8-nucleado en todos los óvulos, y que presentan deposición de calosa en los estadios avanzados. Sin

  16. Molecular cloning and characterization of drought stress responsive abscisic acid-stress-ripening (Asr 1) gene from wild jujube, Ziziphus nummularia (Burm.f.) Wight & Arn.

    Padaria, Jasdeep Chatrath; Yadav, Radha; Tarafdar, Avijit; Lone, Showkat Ahmad; Kumar, Kanika; Sivalingam, Palaiyur Nanjappan

    2016-08-01

    Drought is a calamitous abiotic stress hampering agricultural productivity all over the world and its severity is likely to increase further. Abscisic acid-stress-ripening proteins (ASR), are a group of small hydrophilic proteins which are induced by abscisic acid, stress and ripening in many plants. In the present study, ZnAsr 1 gene was fully characterized for the first time from Ziziphus nummularia, which is one of the most low water forbearing plant. Full length ZnAsr 1 gene was characterised and in silico analysis of ZnASR1 protein was done for predicting its phylogeny and physiochemical properties. To validate transcriptional pattern of ZnAsr 1 in response to drought stress, expression profiling in polyethylene glycol (PEG) induced Z. nummularia seedlings was studied by RT-qPCR analysis and heterologous expression of the recombinant ZnAsr1 in Escherichia coli. The nucleotide sequence analysis revealed that the complete open reading frame of ZnAsr 1 is 819 bp long encoding a protein of 273 amino acid residues, consisting of a histidine rich N terminus with an abscisic acid/water deficit stress domain and a nuclear targeting signal at the C terminus. In expression studies, ZnAsr 1 gene was found to be highly upregulated under drought stress and recombinant clones of E. coli cells expressing ZnASR1 protein showed better survival in PEG containing media. ZnAsr1 was proven to enhance drought stress tolerance in the recombinant E.coli cells expressing ZnASR1. The cloned ZnAsr1 after proper validation in a plant system, can be used to develop drought tolerant transgenic crops. PMID:27209581

  17. Low Temperature-Induced 30 (LTI30) positively regulates drought stress resistance in Arabidopsis: effect on abscisic acid sensitivity and hydrogen peroxide accumulation

    Shi, Haitao; Chen, Yinhua; Qian, Yongqiang; Chan, Zhulong

    2015-01-01

    As a dehydrin belonging to group II late embryogenesis abundant protein (LEA) family, Arabidopsis Low Temperature-Induced 30 (LTI30)/XERO2 has been shown to be involved in plant freezing stress resistance. However, the other roles of AtLTI30 remain unknown. In this study, we found that the expression of AtLTI30 was largely induced by drought stress and abscisic acid (ABA) treatments. Thereafter, AtLTI30 knockout mutants and overexpressing plants were isolated to investigate the possible invol...

  18. Influence of mineral nutrition, ozone, and acid fog on abscisic acid and indole acetic acid in needles of Picea abies (L. ) Karst

    Fackler, U.; Huber, W.; Hock, B.

    1986-09-01

    The phytohormones abscisic acid and auxin (total, free, and alkali-labile IAA) were quantified in needles from spruces which had been exposed to air pollutants under different controlled climatic conditions within the MAGL pilot project. Increased concentrations of ABA were found especially in the most recent needles after ozone treatment. Noticeable changes in auxin concentrations could not be observed. These results should be backed up by further experiments with more samples in order to gain insight into the hormonal balance of plants under stress by air pollution.

  19. Calcium partitioning and allocation and blossom-end rot development in tomato plants in response to whole-plant and fruit-specific abscisic acid treatments

    Tonetto de Freitas, Sergio; McElrone, Andrew J.; Shackel, Kenneth A.; Mitcham, Elizabeth J

    2013-01-01

    The mechanisms regulating Ca2+ partitioning and allocation in plants and fruit remain poorly understood. The objectives of this study were to determine Ca2+ partitioning and allocation in tomato plants and fruit in response to whole-plant and fruit-specific abscisic acid (ABA) treatments, as well as to analyse the effect of changes in Ca2+ partitioning and allocation on fruit susceptibility to the Ca2+ deficiency disorder blossom-end rot (BER) under water stress conditions. Tomato plants of t...

  20. Onset of herbivore-induced resistance in systemic tissue primed for jasmonate-dependent defenses is activated by abscisic acid

    Irene A. Vos

    2013-12-01

    Full Text Available In Arabidopsis, the MYC2 transcription factor on the one hand and the AP2/ERF transcription factors ORA59 and ERF1 on the other hand regulate distinct branches of the jasmonic acid (JA signaling pathway in an antagonistic fashion, co-regulated by abscisic acid (ABA and ethylene, respectively. Feeding by larvae of the specialist herbivorous insect Pieris rapae (small cabbage white butterfly results in activation of the MYC-branch and concomitant suppression of the ERF-branch in insect-damaged leaves. Here we investigated differential JA signaling activation in undamaged systemic leaves of P. rapae-infested plants. We found that the MYC2 transcription factor gene was induced both in the local insect-damaged leaves and the systemic undamaged leaves of P. rapae-infested Arabidopsis plants. However, in contrast to the insect-damaged leaves, the undamaged tissue did not show activation of the MYC-branch marker gene VSP1. Comparison of the hormone signal signature revealed that the levels of JA and (+-7-iso-jasmonoyl-L-isoleucine (JA-Ile raised to similar extents in locally damaged and systemically undamaged leaves, but the production of ABA and the JA precursor 12-oxo-phytodienoic acid (OPDA was enhanced only in the local herbivore-damaged leaves, and not in the distal undamaged leaves. Challenge of undamaged leaves of pre-infested plants with either P. rapae larvae or exogenously applied ABA led to potentiated expression levels of MYC2 and VSP1, with the latter reaching extremely high expression levels. Moreover, P. rapae-induced resistance, as measured by reduction of caterpillar growth on pre-infested plants, was blocked in the ABA biosynthesis mutant aba2-1, that was also impaired in P. rapae-induced expression of VSP1. Together, these results suggest that ABA is a crucial regulator of herbivore-induced resistance by activating primed JA-regulated defense responses upon secondary herbivore attack in Arabidopsis.

  1. Analysis of ADP-glucose pyrophosphorylase expression during turion formation induced by abscisic acid in Spirodela polyrhiza (greater duckweed

    Wang Wenqin

    2012-01-01

    Full Text Available Abstract Background Aquatic plants differ in their development from terrestrial plants in their morphology and physiology, but little is known about the molecular basis of the major phases of their life cycle. Interestingly, in place of seeds of terrestrial plants their dormant phase is represented by turions, which circumvents sexual reproduction. However, like seeds turions provide energy storage for starting the next growing season. Results To begin a characterization of the transition from the growth to the dormant phase we used abscisic acid (ABA, a plant hormone, to induce controlled turion formation in Spirodela polyrhiza and investigated their differentiation from fronds, representing their growth phase, into turions with respect to morphological, ultra-structural characteristics, and starch content. Turions were rich in anthocyanin pigmentation and had a density that submerged them to the bottom of liquid medium. Transmission electron microscopy (TEM of turions showed in comparison to fronds shrunken vacuoles, smaller intercellular space, and abundant starch granules surrounded by thylakoid membranes. Turions accumulated more than 60% starch in dry mass after two weeks of ABA treatment. To further understand the mechanism of the developmental switch from fronds to turions, we cloned and sequenced the genes of three large-subunit ADP-glucose pyrophosphorylases (APLs. All three putative protein and exon sequences were conserved, but the corresponding genomic sequences were extremely variable mainly due to the invasion of miniature inverted-repeat transposable elements (MITEs into introns. A molecular three-dimensional model of the SpAPLs was consistent with their regulatory mechanism in the interaction with the substrate (ATP and allosteric activator (3-PGA to permit conformational changes of its structure. Gene expression analysis revealed that each gene was associated with distinct temporal expression during turion formation. APL2 and

  2. Regulation of the High-Affinity Nitrate Transport System in Wheat Roots by Exogenous Abscisic Acid and Glutamine

    Chao Cai; Xue-Qiang Zhao; Yong-Guan Zhu; Bin Li; Yi-Ping Tong; Zhen-Sheng Li

    2007-01-01

    Nitrate is a major nitrogen (N) source for most crops.Nitrate uptake by root cells is a key step of nitrogen metabolism and has been widely studied at the physiological and molecular levels.Understanding how nitrate uptake is regulated will help us engineer crops with improved nitrate uptake efficiency.The present study investigated the regulation of the high-affinity nitrate transport system (HATS) by exogenous abscisic acid (ABA) and glutamine (Gin) in wheat (Triticum aestivum L.) roots.Wheat seedlings grown in nutrient solution containing 2 mmollL nitrate as the only nitrogen source for 2 weeks were deprived of N for 4d and were then transferred to nutrient solution containing 50 μmol/L ABA, and 1 mmol/L Gin in the presence or absence of 2 mmol/L nitrate for 0, 0.5, 1, 2, 4, and 8 h.Treated wheat plants were then divided into two groups.One group of plants was used to investigate the mRNA levels of the HATS components NRT2 and NAR2 genes in roots through semi-quantitative RT-PCR approach, and the other set of plants were used to measure high-affinity nitrate influx rates in a nutrient solution containing 0.2 mmol/L 15 N-labeled nitrate.The results showed that exogenous ABA induced the expression of the TaNRT2.1, TaNRT2.2, TaNRT2.3, TaNAR2.1, and TaNAR2.2 genes in roots when nitrate was not present in the nutrient solution, but did not further enhance the induction of these genes by nitrate.Glutamine, which has been shown to inhibit the expression of NRT2 genes when nitrate is present in the growth media, did not inhibit this induction.When Gin was supplied to a nitrate-free nutrient solution, the expression of these five genes in roots was induced.These results imply that the inhibition by Gin of NRT2 expression occurs only when nitrate is present in the growth media.Although exogenous ABA and Gin induced HATS genes in the roots of wheat, they did not induce nitrate influx.

  3. The small ethylene response factor ERF96 is involved in the regulation of the abscisic acid response in Arabidopsis

    Xiaoping eWang

    2015-11-01

    Full Text Available Ethylene regulates many aspects of plant growth and development including seed germination, leaf senescence, and fruit ripening, and of plant responses to environmental stimuli including both biotic and abiotic stresses. Ethylene Response Factors (ERFs are plant-specific transcription factors and are a subfamily of the AP2 (APETALA2/ERF transcription factor family. The function of many members in this large gene family remains largely unknown. ERF96, a member of the Group IX ERF family transcription factors, has recently been shown to be a transcriptional activator that is involved in plant defense response in Arabidopsis. Here we provide evidence that ERF96 is a positive regulator of abscisic acid (ABA responses. Bioinformatics analysis indicated that there are a total four small ERFs in Arabidopsis including ERF95, ERF96, ERF97 and ERF98, and that ERF96 forms a cluster with ERF95 and ERF97. By using quantitative RT-PCR, we found that ERF96 is expressed in all tissues and organs examined except roots, with relatively high expression in flowers and seeds. Results from the protoplast transfection assay results indicated that the EDLL motif-containing C-terminal domain is responsible for ERF96’s transcriptional activity. Although loss-of-function mutant of ERF96 was morphologically similar to wild type plants, transgenic plants overexpressing ERF96 had smaller rosette size and were delayed in flowering time. In ABA sensitivity assays, we found that ERF96 overexpression plants were hypersensitive to ABA in terms of ABA inhibition of seed germination, early seedling development and root elongation. Consistent with these observations, elevated transcript levels of some ABA-responsive genes including RD29A, ABI5, ABF3, ABF4, P5CS and COR15A were observed in the transgenic plants in the presence of ABA. However, in the absence of ABA treatment, the transcript levels of these ABA-responsive genes remained largely unchanged. Our experiments also showed

  4. Efectos genéticos de la formación de calosa en ápices radicales de líneas de maíz resistentes y susceptibles a suelos ácidos Genetic effects in callose content in root apex of inbred resistant and susceptible corn lines to acid soils

    Alba Lucía Arcos

    2007-01-01

    Full Text Available El objetivo de este trabajo fue estudiar la herencia de la producción de calosa utilizando líneas endogámicas de maíz. Seleccionando 14 líneas (7 tolerantes y 7 susceptibles a suelos ácidos se formó un dialelo que fue probado en campo y en invernadero. Se determinó el contenido de calosa en los 91 cruzamientos resultantes y los 14 progenitores. Para ello se colocaron las semillas en cámara de crecimiento en condiciones controladas. Después de 4-5 días las plántulas fueron transferidas a cubetas que contenían solución nutritiva con aireación constante. Luego de 48 horas se adicionaron 25 µM de aluminio (AlCl3 a cada una de las cubetas y se mantuvieron por 12 horas. Se cortaron tres ápices radicales de cada genotipo y se mantuvieron en etanol 96%. Para medir el contenido de calosa se utilizó Methyl blue como colorante, este forma un complejo con la calosa llamado Siruflúor-calosa, que es medido con el espectrofotómetro de fluorescencia. Se encontraron diferencias significativas para los progenitores, los cruzamientos y los progenitores Vs cruzamientos. El contenido de calosa de los progenitores varió de 0.746 a 2.035 µg PE/cm ápice de raíz. La heterosis varió desde -21.2% a 276.3%. La Habilidad Combinatoria General (HCG y la Habilidad Combinatoria Específica (HCE fueron altamente significativas, lo que indica que tanto los efectos genéticos aditivos y no aditivos fueron importantes en la herencia de calosa. El 46% de SC entre cruzamientos correspondió a la HCG y el 54% a la HCE. El coeficiente de correlación entre el contenido de calosa y la producción de grano del maíz en el campo fue negativo aunque no significativo (r = -0.38.The main objective of this work was to identify genetic parameters that are related to callose accumulation using tropical inbreeds corn. Fourteen inbreed lines selected for different levels of tolerance to acid soils were chosen and a diallel among them was generated. The seeds were grown

  5. Changes in abundance of an abscisic acid-responsive, early cysteine-labeled metallothionein transcript during pollen embryogenesis in bread wheat (Triticum aestivum).

    Reynolds, T L; Crawford, R L

    1996-12-01

    A clone for an embryoid-abundant, early cysteine-labeled metallothionein (EcMt) gene has been isolated from a wheat pollen embryoid cDNA library. The transcript of this gene was only expressed in embryogenic microspores, pollen embryoids, and developing zygotic embryos of wheat. Accumulation of the EcMt mRNA showed a direct and positive correlation with an increase of the plant hormone, abscisic acid (ABA) in developing pollen embryoids. Treating cultures with an inhibitor of ABA biosynthesis, fluridone, suppressed not only ABA accumulation but also the appearance of the EcMt gene transcript and the ability of microspores to form embryoids. These results suggest that the EcMt gene may act as a molecular marker for pollen embryogenesis because ABA biosynthesis is accompanied by the increased expression of the EcMt transcript that coincides with the differentiation of pollen embryoids in wheat anther cultures. PMID:8980534

  6. A maize calcium-dependent protein kinase gene, ZmCPK4, positively regulated abscisic acid signaling and enhanced drought stress tolerance in transgenic Arabidopsis.

    Jiang, Shanshan; Zhang, Dan; Wang, Li; Pan, Jiaowen; Liu, Yang; Kong, Xiangpei; Zhou, Yan; Li, Dequan

    2013-10-01

    Calcium-dependent protein kinases (CDPKs) play essential roles in calcium-mediated signal transductions in plant response to abiotic stress. Several members have been identified to be regulators for plants response to abscisic acid (ABA) signaling. Here, we isolated a subgroup I CDPK gene, ZmCPK4, from maize. Quantitative real time PCR (qRT-PCR) analysis revealed that the ZmCPK4 transcripts were induced by various stresses and signal molecules. Transient and stable expression of the ZmCPK4-GFP fusion proteins revealed ZmCPK4 localized to the membrane. Moreover, overexpression of ZmCPK4 in the transgenic Arabidopsis enhanced ABA sensitivity in seed germination, seedling growth and stomatal movement. The transgenic plants also enhanced drought stress tolerance. Taken together, the results suggest that ZmCPK4 might be involved in ABA-mediated regulation of stomatal closure in response to drought stress. PMID:23911729

  7. Up-regulating the abscisic acid inactivation gene ZmABA8ox1b contributes to seed germination heterosis by promoting cell expansion.

    Li, Yangyang; Wang, Cheng; Liu, Xinye; Song, Jian; Li, Hongjian; Sui, Zhipeng; Zhang, Ming; Fang, Shuang; Chu, Jinfang; Xin, Mingming; Xie, Chaojie; Zhang, Yirong; Sun, Qixin; Ni, Zhongfu

    2016-04-01

    Heterosis has been widely used in agriculture, but the underlying molecular principles are still largely unknown. During seed germination, we observed that maize (Zea mays) hybrid B73/Mo17 was less sensitive than its parental inbred lines to exogenous abscisic acid (ABA), and endogenous ABA content in hybrid embryos decreased more rapidly than in the parental inbred lines. ZmABA8ox1b, an ABA inactivation gene, was consistently more highly up-regulated in hybrid B73/Mo17 than in its parental inbred lines at early stages of seed germination. Moreover, ectopic expression of ZmABA8ox1b obviously promoted seed germination in Arabidopsis Remarkably, microscopic observation revealed that cell expansion played a major role in the ABA-mediated maize seed germination heterosis, which could be attributed to the altered expression of cell wall-related genes. PMID:27034328

  8. In vitro Transient Expression System of Latex C-serum was used for Analysis of Hevein Promoter in Response to Abscisic Acid in Hevea brasiliensis

    Xiao-Wen Fei; Xiao-Dong Deng

    2008-01-01

    Hevein has been found to be an essential element in coagulation of rubber particles in latex of rubber trees. In a previous study, we cloned a 1 241-bp fragment of a 5' upstream region of the hevein gene by genome walking. This fragment was analyzed by a 5' end nested deletion method in the present study, fused with a uidA (gus) gene to produce a series of tested constructs, which were transferred into C-serum of latex and the Gus activities were detected. Results showed that the fragment from -749 to -292 was sufficient for expression of gus gene in latex, and the fragment from -292 to -168 was crucial in response to abscisic acid inducement. In a transient transgenic test of rubber leaf with particle bombardment, construct Hev749 conferred gus-specific expression in veins, in which the latex tubes mainly distributed. This implies that the fragment from -749 to -292 was laticiferous-specific.

  9. Abscisic (ABA)-aldehyde is a precursor to, and 1',4'-trans-ABA-diol a catabolite of, ABA in apple

    Previous 18O labeling studies of abscisic acid (ABA) have shown that apple (Malus domestica Borkh. cv Granny Smith) fruits synthesize a majority of [18O]ABA with the label incorporated in the 1'-hydroxyl position and unlabeled in the carboxyl group (JAD Zeevaart, TG Heath, DA Gage [1989] Plant Physiol 91: 1594-1601). It was proposed that exchange of 18O in the side chain with the medium occurred at an aldehyde intermediate stage of ABA biosynthesis. We have isolated ABA-aldehyde and 1'-4'-trans-ABA-diol (ABA-trans-diol) from 18O-labeled apple fruit tissue and measured the extent and position of 18O incorporation by tandem mass spectrometry. 18O-Labeling patterns of ABA-aldehyde, ABA-trans-diol, and ABA indicate that ABA-aldehyde is a precursor to, and ABA-trans-diol a catabolite of, ABA. Exchange of 18O in the carbonyl of ABA-aldehyde can be the cause of loss of 18O from the side chain of [18O]ABA. Results of feeding experiments with deuterated substrates provide further support for the precursor-product relationship of ABA-aldehyde → ABA → ABA-trans-diol. The ABA-aldehyde and ABA-trans-diol contents of fruits and leaves were low, approximately 1 and 0.02 nanograms per gram fresh weight for ABA-aldehyde and ABA-trans-diol, respectively, while ABA levels in fruits ranged from 10 to 200 nanograms per gram fresh weight. ABA biosynthesis was about 10-fold lower in fruits than in leaves. In fruits, the majority of ABA was conjugated to β-D-glucopyranosyl abscisate, whereas in leaves ABA was mainly hydroxylated to phaseic acid. Parallel pathways for ABA and trans-ABA biosynthesis and conjugation in fruits and leaves are proposed

  10. The putative E3 ubiquitin ligase ECERIFERUM9 regulates abscisic acid biosynthesis and response during seed germination and postgermination growth in arabidopsis

    Zhao, Huayan

    2014-05-08

    The ECERIFERUM9 (CER9) gene encodes a putative E3 ubiquitin ligase that functions in cuticle biosynthesis and the maintenance of plant water status. Here, we found that CER9 is also involved in abscisic acid (ABA) signaling in seeds and young seedlings of Arabidopsis (Arabidopsis thaliana). The germinated embryos of the mutants exhibited enhanced sensitivity to ABA during the transition from reversible dormancy to determinate seedling growth. Expression of the CER9 gene is closely related to ABA levels and displays a similar pattern to that of ABSCISIC ACID-INSENSITIVE5 (ABI5), which encodes a positive regulator of ABA responses in seeds. cer9 mutant seeds exhibited delayed germination that is independent of seed coat permeability. Quantitative proteomic analyses showed that cer9 seeds had a protein profile similar to that of the wild type treated with ABA. Transcriptomics analyses revealed that genes involved in ABA biosynthesis or signaling pathways were differentially regulated in cer9 seeds. Consistent with this, high levels of ABA were detected in dry seeds of cer9. Blocking ABA biosynthesis by fluridone treatment or by combining an ABA-deficient mutation with cer9 attenuated the phenotypes of cer9. Whereas introduction of the abi1-1, abi3-1, or abi4-103 mutation could completely eliminate the ABA hypersensitivity of cer9, introduction of abi5 resulted only in partial suppression. These results indicate that CER9 is a novel negative regulator of ABA biosynthesis and the ABA signaling pathway during seed germination. © 2014 American Society of Plant Biologists. All Rights Reserved.

  11. Separation of Abscisic Acid, Indole-3-Acetic Acid, Gibberellic Acid in 99 R (Vitis berlandieri x Vitis rupestris) and Rose Oil (Rosa damascena Mill.) by Reversed Phase Liquid Chromatography

    KELEN, Mustafa

    2004-01-01

    Plant hormones, specialized chemical substances produced by plants, are the main internal factors controlling growth and development. In this study the pH and polarity of the mobile phase were taken into consideration to optimize the mobile phase for the chromatographic separation of 3 important plant hormones: abscisic acid (ABA), indole-3-acetic acid (IAA) and gibberellic acid (GA3). pKa values of ABA, IAA and GA3 were determined using retention factors. These 3 hormones were extr...

  12. β-Aminobutyric acid increases abscisic acid accumulation and desiccation tolerance and decreases water use but fails to improve grain yield in two spring wheat cultivars under soil drying

    Du, Yan-Lei; Wang, Zhen-Yu; Fan, Jing-Wei; Turner, Neil C.; Wang, Tao; Li, Feng-Min

    2012-01-01

    A pot experiment was conducted to investigate the effect of the non-protein amino acid, β-aminobutyric acid (BABA), on the homeostasis between reactive oxygen species (ROS) and antioxidant defence during progressive soil drying, and its relationship with the accumulation of abscisic acid (ABA), water use, grain yield, and desiccation tolerance in two spring wheat (Triticum aestivum L.) cultivars released in different decades and with different yields under drought. Drenching the soil with 100...

  13. Nucleotide Variation in the NCED3 Region of Arabidopsis thaliana and its Association Study with Abscisic Acid Content under Drought Stress

    Gang-Ping Hao; Xiu-Hai Zhang; Yong-Qin Wang; Zhong-Yi Wu; Cong-Lin Huang

    2009-01-01

    Drought tolerance is a comprehensive quantitative trait that is being understood further at the molecular genetic level. Abscisic acid (ABA) is the main drought-induced hormone that regulates the expression of many genes related to drought responses. 9-cis-epoxycarotenoid dioxygenase (NCED3) is thought to be a key enzyme in ABA biosynthesis. In this paper, we measured the ABA content increase under drought stress, and sequenced and compared the sequence of AtNCED3 among 22 Arabidopsis thaliana accessions. The results showed that the fold of ABA content increase under drought stress was highly variable among these accessions. High density single nucleotide polymorphism (SNP) and insertion/deletion (indel) were found in the AtNCED3 region, on average one SNP per 87.4 bp and one indel per 502 bp. Nucleotide diversity was significantly lower in the coding region than that in non-coding regions. The results of an association study with ANOVA analysis suggested that the 274th site (P←→S) and the 327th site (P←→R) amino acid variations might be the cause of ABA content increase of 163av accession under drought stress.

  14. Distinct abscisic acid signaling pathways for modulation of guard cell versus mesophyll cell potassium channels revealed by expression studies in Xenopus laevis oocytes

    Sutton, F.; Paul, S. S.; Wang, X. Q.; Assmann, S. M.; Evans, M. L. (Principal Investigator)

    2000-01-01

    Regulation of guard cell ion transport by abscisic acid (ABA) and in particular ABA inhibition of a guard cell inward K(+) current (I(Kin)) is well documented. However, little is known concerning ABA effects on ion transport in other plant cell types. Here we applied patch clamp techniques to mesophyll cell protoplasts of fava bean (Vicia faba cv Long Pod) plants and demonstrated ABA inhibition of an outward K(+) current (I(Kout)). When mesophyll cell protoplast mRNA (mesophyll mRNA) was expressed in Xenopus laevis oocytes, I(Kout) was generated that displayed similar properties to I(Kout) observed from direct analysis of mesophyll cell protoplasts. I(Kout) expressed by mesophyll mRNA-injected oocytes was inhibited by ABA, indicating that the ABA signal transduction pathway observed in mesophyll cells was preserved in the frog oocytes. Co-injection of oocytes with guard cell protoplast mRNA and cRNA for KAT1, an inward K(+) channel expressed in guard cells, resulted in I(Kin) that was similarly inhibited by ABA. However, oocytes co-injected with mesophyll mRNA and KAT1 cRNA produced I(Kin) that was not inhibited by ABA. These results demonstrate that the mesophyll-encoded signaling mechanism could not substitute for the guard cell pathway. These findings indicate that mesophyll cells and guard cells use distinct and different receptor types and/or signal transduction pathways in ABA regulation of K(+) channels.

  15. Maturation in Corymbia torelliana × C. citriodora Stock Plants: Effects of Pruning Height on Shoot Production, Adventitious Rooting Capacity, Stem Anatomy, and Auxin and Abscisic Acid Concentrations

    Ivar Wendling

    2015-10-01

    Full Text Available Repeated pruning of stock plants is a common approach to delaying maturation and maintaining the propagation ability of cuttings, but little is known about the hormonal or anatomical basis for this phenomenon. We tested the effect of two different stock-plant pruning heights (15 cm and 30 cm on shoot production, rooting capacity and rooted cutting vigour of six clones of the eucalypt Corymbia torelliana × C. citriodora. We determined whether differences in rooting potential were related to indole-3-acetic (IAA and abscisic acid (ABA concentrations, or the degree of lignification or sclerification, of the cuttings. Maintaining stock plants at 15 cm height sometimes reduced the production of stem cuttings. However, it often increased the ensuing percentage of cuttings that formed roots, with mean rooting across all clones increasing from 30%–53%. Therefore, the number of rooted cuttings produced by short stock plants was similar to, or higher than, the number produced by tall stock plants. Cuttings from shorter stock plants had faster root elongation and occasionally greater root dry mass, shoot dry mass or shoot height than cuttings from tall stock plants. These differences in rooting potential were generally not related to differences in IAA or ABA concentrations of the cuttings or to differences in their stem anatomy. Pruning at the lower height was more effective in maintaining clonal juvenility, supporting previous findings that stock plant maturation is a limiting factor in clonal propagation of Corymbia torelliana × C. citriodora.

  16. AtPUB 19, a U-Box E3 Ubiquitin Ligase, Negatively Regulates Abscisic Acid and Drought Responses in Arabidopsis thaliana

    Yong-Chang Liu; Yao-Rong Wu; Xia-He Huang; Jie Sun; Qi Xie

    2011-01-01

    Ubiquitination is an important protein post-translational modification,which is involved in various cellular processes in higher plants,and U-box E3 ligases play important roles in diverse functions in eukaryotes.Here,we describe the functions of Arabidopsis thaliana PUB19 (AtPUB19),which we demonstrated in an in vitro assay to encode a U-box type E3 ubiquitin ligase.AtPUB19 was up-regulated by drought,salt,cold,and abscisic acid (ABA).Down-regulation of AtPUB19led to hypersensitivity to ABA,enhanced ABA-induced stomatal closing,and enhanced drought tolerance,while AtPUB 19overexpression resulted in the reverse phenotypes.Molecular analysis showed that the expression levels of a number of ABA and stress marker genes were altered in both AtPUB 19 overexpressing and atpub 19-1 mutant plants.In summary,our data show that AtPUB19 negatively regulates ABA and drought responses in A.thaliana.

  17. The pepper late embryogenesis abundant protein CaLEA1 acts in regulating abscisic acid signaling, drought and salt stress response.

    Lim, Chae Woo; Lim, Sohee; Baek, Woonhee; Lee, Sung Chul

    2015-08-01

    As sessile organisms, plants are constantly challenged by environmental stresses, including drought and high salinity. Among the various abiotic stresses, osmotic stress is one of the most important factors for growth and significantly reduces crop productivity in agriculture. Here, we report a function of the CaLEA1 protein in the defense responses of plants to osmotic stress. Our analyses showed that the CaLEA1 gene was strongly induced in pepper leaves exposed to drought and increased salinity. Furthermore, we determined that the CaLEA1 protein has a late embryogenesis abundant (LEA)_3 homolog domain highly conserved among other known group 5 LEA proteins and is localized in the processing body. We generated CaLEA1-silenced peppers and CaLEA1-overexpressing (OX) transgenic Arabidopsis plants to evaluate their responses to dehydration and high salinity. Virus-induced gene silencing of CaLEA1 in pepper plants conferred enhanced sensitivity to drought and salt stresses, which was accompanied by high levels of lipid peroxidation in dehydrated and NaCl-treated leaves. CaLEA1-OX plants exhibited enhanced sensitivity to abscisic acid (ABA) during seed germination and in the seedling stage; furthermore, these plants were more tolerant to drought and salt stress than the wild-type plants because of enhanced stomatal closure and increased expression of stress-responsive genes. Collectively, our data suggest that CaLEA1 positively regulates drought and salinity tolerance through ABA-mediated cell signaling. PMID:25302464

  18. Putrescine Is Involved in Arabidopsis Freezing Tolerance and Cold Acclimation by Regulating Abscisic Acid Levels in Response to Low Temperature1

    Cuevas, Juan C.; López-Cobollo, Rosa; Alcázar, Rubén; Zarza, Xavier; Koncz, Csaba; Altabella, Teresa; Salinas, Julio; Tiburcio, Antonio F.; Ferrando, Alejandro

    2008-01-01

    The levels of endogenous polyamines have been shown to increase in plant cells challenged with low temperature; however, the functions of polyamines in the regulation of cold stress responses are unknown. Here, we show that the accumulation of putrescine under cold stress is essential for proper cold acclimation and survival at freezing temperatures because Arabidopsis (Arabidopsis thaliana) mutants defective in putrescine biosynthesis (adc1, adc2) display reduced freezing tolerance compared to wild-type plants. Genes ADC1 and ADC2 show different transcriptional profiles upon cold treatment; however, they show similar and redundant contributions to cold responses in terms of putrescine accumulation kinetics and freezing sensitivity. Our data also demonstrate that detrimental consequences of putrescine depletion during cold stress are due, at least in part, to alterations in the levels of abscisic acid (ABA). Reduced expression of NCED3, a key gene involved in ABA biosynthesis, and down-regulation of ABA-regulated genes are detected in both adc1 and adc2 mutant plants under cold stress. Complementation analysis of adc mutants with ABA and reciprocal complementation tests of the aba2-3 mutant with putrescine support the conclusion that putrescine controls the levels of ABA in response to low temperature by modulating ABA biosynthesis and gene expression. PMID:18701673

  19. Mapping intercellular CO2 mole fraction (Ci) in rosa rubiginosa leaves fed with abscisic acid by using chlorophyll fluorescence imaging. Significance Of ci estimated from leaf gas exchange

    Meyer; Genty

    1998-03-01

    Imaging of photochemical yield of photosystem II (PSII) computed from leaf chlorophyll fluorescence images and gas-exchange measurements were performed on Rosa rubiginosa leaflets during abscisic acid (ABA) addition. In air ABA induced a decrease of both the net CO2 assimilation (An) and the stomatal water vapor conductance (gs). After ABA treatment, imaging in transient nonphotorespiratory conditions (0.1% O2) revealed a heterogeneous decrease of PSII photochemical yield. This decline was fully reversed by a transient high CO2 concentration (7400 mol mol-1) in the leaf atmosphere. It was concluded that ABA primarily affected An by decreasing the CO2 supply at ribulose-1,5-bisphosphate carboxylase/oxygenase. Therefore, the An versus intercellular mole fraction (Ci) relationship was assumed not to be affected by ABA, and images of Ci and gs were constructed from images of PSII photochemical yield under nonphotorespiratory conditions. The distribution of gs remained unimodal following ABA treatment. A comparison of calculations of Ci from images and gas exchange in ABA-treated leaves showed that the overestimation of Ci estimated from gas exchange was only partly due to heterogeneity. This overestimation was also attributed to the cuticular transpiration, which largely affects the calculation of the leaf conductance to CO2, when leaf conductance to water is low. PMID:9501127

  20. Induction of Protection against Paraquat-induced Oxidative Damage by Abscisic Acid in Maize Leaves is Mediated through Mitogen-activated Protein Kinase

    Hai-Dong Ding; Xiao-Hua Zhang; Shu-Cheng Xu; Li-Li Sun; Ming-Yi Jiang; A-Ying Zhang; Yin-Gen Jin

    2009-01-01

    Mitogen-activated protein kinase (MAPK) cascade has been shown to be important components In stress signal trans-duction pathway. In the present study, protection of maize seedlings (Zea mays L.) against paraquat-generated oxidative toxicity by abscisic acid (ABA), its association with MAPK and ZmMPK5, a candidate for MAPK were investigated. Treatment of maize leaves with exogenous ABA led to significant decreases in the content of malondialdehyde, the percentage of ion leakage and the level of protein oxidation (in terms of carbonyl groups) under paraquat (PQ) stress. However, such decreases were blocked by the pretreatment with two MAPK kinase inhibitors PD98059 and U0126. The damage caused by PQ was further aggravated by inhibitors. Two inhibitors also suppressed the total activities of the antioxidant enzymes superoxide dismutase (SOD, EC 1.15.1.1), catalase (CAT, EC 1.11.1.6), ascorbate peroxidase (APX, EC 1.11.1.11), and glutathione reductase (GR, EC 1.6.4.2). Besides, treatment with PQ stimulated the activation of a 46 kDa MAPK, which was identified as ZmMPK5 by in-gel kinase assay with immunoprecipitation. These results reveal that ABA-induced protection against PQ-generated oxidative damage is mediated through MAPK cascade in maize leaves, in which ZmMPK5, a candidate for MAPK, is demonstrated to be involved.

  1. Genetic Analysis of Physcomitrella patens Identifies ABSCISIC ACID NON-RESPONSIVE, a Regulator of ABA Responses Unique to Basal Land Plants and Required for Desiccation Tolerance[OPEN

    Kamisugi, Yasuko; Trinh, Chi H.; Schmutz, Jeremy; Muchero, Wellington; Melkonian, Michael; Rothfels, Carl J.; Li, Fay-Wei; Larsson, Anders; Edwards, Thomas A.

    2016-01-01

    The anatomically simple plants that first colonized land must have acquired molecular and biochemical adaptations to drought stress. Abscisic acid (ABA) coordinates responses leading to desiccation tolerance in all land plants. We identified ABA nonresponsive mutants in the model bryophyte Physcomitrella patens and genotyped a segregating population to map and identify the ABA NON-RESPONSIVE (ANR) gene encoding a modular protein kinase comprising an N-terminal PAS domain, a central EDR domain, and a C-terminal MAPKKK-like domain. anr mutants fail to accumulate dehydration tolerance-associated gene products in response to drought, ABA, or osmotic stress and do not acquire ABA-dependent desiccation tolerance. The crystal structure of the PAS domain, determined to 1.7-Å resolution, shows a conserved PAS-fold that dimerizes through a weak dimerization interface. Targeted mutagenesis of a conserved tryptophan residue within the PAS domain generates plants with ABA nonresponsive growth and strongly attenuated ABA-responsive gene expression, whereas deleting this domain retains a fully ABA-responsive phenotype. ANR orthologs are found in early-diverging land plant lineages and aquatic algae but are absent from more recently diverged vascular plants. We propose that ANR genes represent an ancestral adaptation that enabled drought stress survival of the first terrestrial colonizers but were lost during land plant evolution. PMID:27194706

  2. Effect of abscisic acid on biochemical constituents, enzymatic and non enzymatic antioxidant status of lettuce (Lactuca sativa L. under varied irrigation regimes

    Mohamed A. Al Muhairi

    2015-12-01

    Full Text Available Economically important vegetable crop lettuce (Lactuca sativa L. of family Asteraceae was selected for the present investigation. It is being cultivated in UAE due to its commercial importance. In lettuce cultivation, the major problem is the requirement of large quantities of irrigation water. The present study was aimed to reduce the water consumption of lettuce cultivation; for that, a varied irrigation regime was used with the application of abscisic acid (ABA. The parameters studied were biochemical constituents, antioxidant potential and antioxidant enzymes’ activities in lettuce plants under drought stress and its response to ABA under stress. Drought stress caused an increase in the biochemical constituents like proline and amino acid contents when compared with control and also increased under individual ABA treatments and treatments under drought stress. The non-enzymatic antioxidant molecules like ascorbate and α-tocopherol showed significant increase under drought condition in lettuce. ABA slightly reduced these contents. The antioxidant enzymes like superoxide dismutase, catalase and peroxidase showed significant increase under drought condition and ABA caused significant enhancement in these antioxidant enzymes under drought stress and also in unstressed conditions, thereby protecting the plants from the deleterious effects of drought stress. From the results of this investigation, it can be concluded that ABA in 10 mg g−1 can be used as a potential tool to minimise the drought stress effects in lettuce cultivation.

  3. Identification of quantitative trait locus for abscisic acid responsiveness on chromosome 5A and association with dehydration tolerance in common wheat seedlings.

    Iehisa, Julio C M; Matsuura, Takakazu; Mori, Izumi C; Takumi, Shigeo

    2014-01-15

    The phytohormone abscisic acid (ABA) plays important roles in response to environmental stress as well as in seed maturation and dormancy. In common wheat, quantitative trait loci (QTLs) for ABA responsiveness at the seedling stage have been reported on chromosomes 1B, 2A, 3A, 6D and 7B. In this study, we identified a novel QTL for ABA responsiveness on chromosome 5A using an F2 population derived from a cross between the common wheat cultivar Chinese Spring (CS) and a chromosome substitution line of CS with chromosome 5A of cultivar Hope (Hope5A). This QTL was found in a similar chromosomal region to previously reported QTLs for drought tolerance and seed dormancy. Physiological characterization of the QTL revealed a small effect on dehydration tolerance and seed dormancy. The rate of water loss from leaves during dehydration was lower, and transcript accumulation of the cold responsive (COR)/late embryogenesis abundant (LEA) genes Wrab18 and Wdhn13 tended to be higher under dehydration stress in F2 individuals carrying the Hope allele of the QTL, which also showed higher ABA responsiveness than the CS allele-carrying individuals. Seed dormancy of individuals carrying the Hope allele also tended to be lower than those carrying the CS allele. Our results suggest that variation in ABA responsiveness among common wheat cultivars is at least partly determined by the 5A QTL, and that this QTL contributes to development of dehydration and preharvest sprouting tolerance. PMID:24331416

  4. A new role for an old enzyme: Nitrate reductase-mediated nitric oxide generation is required for abscisic acid-induced stomatal closure in Arabidopsis thaliana

    Desikan, Radhika; Griffiths, Rachael; Hancock, John; Neill, Steven

    2002-01-01

    The plant hormone abscisic acid (ABA), synthesized in response to water-deficit stress, induces stomatal closure via activation of complex signaling cascades. Recent work has established that nitric oxide (NO) is a key signaling molecule mediating ABA-induced stomatal closure. However, the biosynthetic origin of NO in guard cells has not yet been resolved. Here, we provide pharmacological, physiological, and genetic evidence that NO synthesis in Arabidopsis guard cells is mediated by the enzyme nitrate reductase (NR). Guard cells of wild-type Arabidopsis generate NO in response to treatment with ABA and nitrite, a substrate for NR. Moreover, NR-mediated NO synthesis is required for ABA-induced stomatal closure. However, in the NR double mutant, nia1, nia2 that has diminished NR activity, guard cells do not synthesize NO nor do the stomata close in response to ABA or nitrite, although stomatal opening is still inhibited by ABA. Furthermore, by using the ABA-insensitive (ABI) abi1–1 and abi2–1 mutants, we show that the ABI1 and ABI2 protein phosphatases are downstream of NO in the ABA signal-transduction cascade. These data demonstrate a previously uncharacterized signaling role for NR, that of mediating ABA-induced NO synthesis in Arabidopsis guard cells. PMID:12446847

  5. Osabc1k8, an abc1-like kinase gene, mediates abscisic acid sensitivity and dehydration tolerance response in rice seedlings

    The activity of bc1 complex kinase (ABC1K) protein family, which widely exists in prokaryotes and eukaryotes, consists of 15 members in rice, and the role of this family in plants has not yet been studied in details. In this study, a novel function of OsABC1K8 (LOC-Os06g48770), a member of rice ABC1K family, was characterized. The transcript level of OsABC1K8 changes in response to salt, dehydration, cold, PEG, oxidative (H/sub 2/O/sub 2/) stresses, or abscisic acid (ABA) treatment. Overexpression of OsABC1K8 significantly increased sensitivity to dehydration and reduced sensitivity to ABA. In the contrast, RNAi transgenic lines displayed significantly reduced sensitivity to dehydration stress and increased sensitivity to ABA. Furthermore, the transcriptional levels of several ABA/stress-regulated responsive genes were suppressed in OsABC1K8 over-expressing plants under dehydration stress. In conclusion, our results suggested that OsABC1K8 is a negative regulator in response to dehydration stress through an ABA-dependent pathway. (author)

  6. Regulation of auxin, abscisic acid and salicylic acid levels by ascorbate application under heat stress in sensitive and tolerant maize leaves.

    Dinler, Burcu Seckin; Demir, Emel; Kompe, Yasemin Ozdener

    2014-12-01

    In the present study, the effect of ascorbic acid (5 mM) on some physiological parameters and three hormones (auxin, abscisic acid, salicylic acid) was determined under heat stress (40 °C) in maize tolerant cv. (MAY 69) and sensitive cv. SHEMAL (SH) at 0 h, 4 h and 8 h. Heat stress reduced total chlorophyll content (CHL), relative water content (RWC) and stomatal conductance (gs) in SH but did not lead to changes in MAY 69 at 4 h and 8 h. However, pretreatment with ascorbic acid increased (CHL), (RWC) and (gs) in SH under heat stress while it reduced MDA content significantly in both cv. We also observed that heat stress led to a reduction in SA level but increased ABA and IAA levels in SH, whereas it increased SA and IAA levels but did not change ABA level in MAY 69 at 4 h. Furthermore, in SH, ASC application under heat stress increased SA level and decreased IAA and ABA levels at 4 h, but it had no effect on SA and ABA at 8 h. PMID:25475985

  7. Low Temperature-Induced 30 (LTI30 positively regulates drought stress resistance in Arabidopsis: effect on abscisic acid sensitivity and hydrogen peroxide accumulation

    Haitao eShi

    2015-10-01

    Full Text Available As a dehydrin belonging to group II late embryogenesis abundant protein (LEA family, Arabidopsis Low Temperature-Induced 30 (LTI30/XERO2 has been shown to be involved in plant freezing stress resistance. However, the other roles of AtLTI30 remain unknown. In this study, we found that the expression of AtLTI30 was largely induced by drought stress and abscisic acid (ABA treatments. Thereafter, AtLTI30 knockout mutants and overexpressing plants were isolated to investigate the possible involvement of AtLTI30 in ABA and drought stress responses. AtLTI30 knockout mutants were less sensitive to ABA-mediated seed germination, while AtLTI30 overexpressing plants were more sensitive to ABA compared with wild type (WT. Consistently, the AtLTI30 knockout mutants displayed decreased drought stress resistance, while the AtLTI30 overexpressing plants showed improved drought stress resistance compared with WT, as evidenced by a higher survival rate and lower leaf water loss than WT after drought stress. Moreover, manipulation of AtLTI30 expression positively regulated the activities of catalases (CATs and endogenous proline content, as a result, negatively regulated drought stress-triggered hydrogen peroxide (H2O2 accumulation. All these results indicate that AtLTI30 is a positive regulator of plant drought stress resistance, partially through the modulation of ABA sensitivity, H2O2 and proline accumulation.

  8. The potato suberin feruloyl transferase FHT which accumulates in the phellogen is induced by wounding and regulated by abscisic and salicylic acids.

    Boher, Pau; Serra, Olga; Soler, Marçal; Molinas, Marisa; Figueras, Mercè

    2013-08-01

    The present study provides new insights on the role of the potato (Solanum tuberosum) suberin feruloyl transferase FHT in native and wound tissues, leading to conclusions about hitherto unknown properties of the phellogen. In agreement with the enzymatic role of FHT, it is shown that its transcriptional activation and protein accumulation are specific to tissues that undergo suberization such as the root boundary layers of the exodermis and the endodermis, along with the tuber periderm. Remarkably, FHT expression and protein accumulation within the periderm is restricted to the phellogen derivative cells with phellem identity. FHT levels in the periderm are at their peak near harvest during periderm maturation, with the phellogen becoming meristematically inactive and declining thereafter. However, periderm FHT levels remain high for several months after harvest, suggesting that the inactive phellogen retains the capacity to synthesize ferulate esters. Tissue wounding induces FHT expression and the protein accumulates from the first stages of the healing process onwards. FHT is up-regulated by abscisic acid and down-regulated by salicylic acid, emphasizing the complex regulation of suberin synthesis and wound healing. These findings open up new prospects important for the clarification of the suberization process and yield important information with regard to the skin quality of potatoes. PMID:23918964

  9. Transport and concentration of abscisic acid (ABA) and auxin (IAA) in deciduous and coniferous trees. Transport und Gehalt von Abscisinsaeure (ABA) und Auxin (IAA) in Laub- und Nadelblaettern

    Hartung, W.

    1988-09-01

    Abscisic acid and indoleacetic acid were chosen to examine whether intact deciduous and coniferous tissues from spruce, hemlock fir, spinage, barley and sorrel or isolated mesophyll protoplasts from barley and closing cell preparations from Valerianella locusta are affected by sulphur dioxide in terms of changes in the concentration, transportation and distribution of such plant hormones. The distribution of phytohormones like ABA and IAA over the individual cell compartments is determined by the different pH gradients of the latter. Owing to their acidity these hormones are accumulated in alkaline cell inclusion bodies like chloroplasts and cytosol. Potentially acid air pollutants like SO{sub 2} and NO{sub x} lead to acidification of previously alkaline cell compartments, due to which fact the cellular pH gradients are reduced. This, in turn, gives rise to a redistribution of phytohormones to the effect that certain target cells such as closing cells of leaves or meristem cells come under the influence of altered hormone concentrations and compositions. This is bound to affect the processes controlling the development, growth and stress behaviour of plants. (orig.) With 55 refs., 2 tabs., 16 figs.

  10. Polyphenolic responses of grapevine berries to light, temperature, oxidative stress, abscisic acid and jasmonic acid show specific developmental-dependent degrees of metabolic resilience to perturbation.

    Degu, Asfaw; Ayenew, Biruk; Cramer, Grant R; Fait, Aaron

    2016-12-01

    Grape-berries are exposed to a plethora of abiotic and biotic stimuli during their development. The developmental and temporal regulation of grape berry polyphenol metabolism in response to various cues was investigated using LC-QTOF-MS based metabolite profiling. High light (2500μmolm(-2)s(-1)), high temperature (40°C), jasmonic acid (200μM), menadione (120μM) and abscisic acid (3.026mM) treatments were applied to detached berries. Greater magnitudes of metabolite fluctuations characterize the pre-veraison berries than the veraison stage in response to the treatments. Furthermore, a tighter co-response of metabolic processes was shown at veraison, likely supporting the resilience to change in response to stress. High temperature and ABA treatments led to greater magnitudes of change during the course of the experiment. The present study demonstrates the occurrence of differential patterns of metabolic responses specific to individual cues and berry developmental stage, which in the field are commonly associated and thus hardly discernable. PMID:27374601

  11. Chloride-inducible transient apoplastic alkalinizations induce stomata closure by controlling abscisic acid distribution between leaf apoplast and guard cells in salt-stressed Vicia faba.

    Geilfus, Christoph-Martin; Mithöfer, Axel; Ludwig-Müller, Jutta; Zörb, Christian; Muehling, Karl H

    2015-11-01

    Chloride stress causes the leaf apoplast transiently to alkalize, an event that is presumed to contribute to the ability of plants to adapt to saline conditions. However, the initiation of coordinated processes downstream of the alkalinization is unknown. We hypothesize that chloride-inducible pH dynamics are a key chemical feature modulating the compartmental distribution of abscisic acid (ABA) and, as a consequence, affecting stomata aperture. Apoplastic pH and stomata aperture dynamics in intact Vicia faba leaves were monitored by microscopy-based ratio imaging and porometric measurements of stomatal conductance. ABA concentrations in leaf apoplast and guard cells were compared with pH dynamics by gas-chromatography-mass-spectrometry (GC-MS) and liquid-chromatography-tandem-mass spectrometry (LC-MS/MS). Results demonstrate that, upon chloride addition to roots, an alkalizing factor that initiates the pH dynamic propagates from root to leaf in a way similar to xylem-distributed water. In leaves, it induces a systemic transient apoplastic alkalinization that causes apoplastic ABA concentration to increase, followed by an elevation of endogenous guard cell ABA. We conclude that the transient alkalinization, which is a remote effect of chloride stress, modulates the compartmental distribution of ABA between the leaf apoplast and the guard cells and, in this way, is instrumental in inducing stomata closure during the beginning of salinity. PMID:26096890

  12. Fruit load induces changes in global gene expression and in abscisic acid (ABA) and indole acetic acid (IAA) homeostasis in citrus buds.

    Shalom, Liron; Samuels, Sivan; Zur, Naftali; Shlizerman, Lyudmila; Doron-Faigenboim, Adi; Blumwald, Eduardo; Sadka, Avi

    2014-07-01

    Many fruit trees undergo cycles of heavy fruit load (ON-Crop) in one year, followed by low fruit load (OFF-Crop) the following year, a phenomenon known as alternate bearing (AB). The mechanism by which fruit load affects flowering induction during the following year (return bloom) is still unclear. Although not proven, it is commonly accepted that the fruit or an organ which senses fruit presence generates an inhibitory signal that moves into the bud and inhibits apical meristem transition. Indeed, fruit removal from ON-Crop trees (de-fruiting) induces return bloom. Identification of regulatory or metabolic processes modified in the bud in association with altered fruit load might shed light on the nature of the AB signalling process. The bud transcriptome of de-fruited citrus trees was compared with those of ON- and OFF-Crop trees. Fruit removal resulted in relatively rapid changes in global gene expression, including induction of photosynthetic genes and proteins. Altered regulatory mechanisms included abscisic acid (ABA) metabolism and auxin polar transport. Genes of ABA biosynthesis were induced; however, hormone analyses showed that the ABA level was reduced in OFF-Crop buds and in buds shortly following fruit removal. Additionally, genes associated with Ca(2+)-dependent auxin polar transport were remarkably induced in buds of OFF-Crop and de-fruited trees. Hormone analyses showed that auxin levels were reduced in these buds as compared with ON-Crop buds. In view of the auxin transport autoinhibition theory, the possibility that auxin distribution plays a role in determining bud fate is discussed. PMID:24706719

  13. Abscisic Acid Induced Changes in Production of Primary and Secondary Metabolites, Photosynthetic Capacity, Antioxidant Capability, Antioxidant Enzymes and Lipoxygenase Inhibitory Activity of Orthosiphon stamineus Benth.

    Mohd Hafiz Ibrahim

    2013-07-01

    Full Text Available An experiment was conducted to investigate and distinguish the relationships in the production of total phenolics, total flavonoids, soluble sugars, H2O2, O2−, phenylalanine ammonia lyase (PAL activity, leaf gas exchange, antioxidant activity, antioxidant enzyme activity [ascorbate peroxidase (APX, catalase (CAT, superoxide dismutase (SOD and Lipoxygenase inhibitory activity (LOX] under four levels of foliar abscisic acid (ABA application (0, 2, 4, 6 µM for 15 weeks in Orthosiphon stamineus Benth. It was found that the production of plant secondary metabolites, soluble sugars, antioxidant activity, PAL activity and LOX inhibitory activity was influenced by foliar application of ABA. As the concentration of ABA was increased from 0 to 6 µM the production of total phenolics, flavonoids, sucrose, H2O2, O2−, PAL activity and LOX inhibitory activity was enhanced. It was also observed that the antioxidant capabilities (DPPH and ORAC were increased. This was followed by increases in production of antioxidant enzymes APX, CAT and SOD. Under high application rates of ABA the net photosynthesis and stomatal conductance was found to be reduced. The production of primary and secondary metabolites displayed a significant positive relationship with H2O2 (total phenolics, r2 = 0.877; total flavonoids, r2 = 0.812; p ≤ 0.05 and O2− (total phenolics, r2 = 0.778; total flavonoids, r2 = 0.912; p ≤ 0.05. This indicated that increased oxidative stress at high application rates of ABA, improved the production of phytochemicals.

  14. Silencing the SpMPK1, SpMPK2, and SpMPK3 Genes in Tomato Reduces Abscisic Acid—Mediated Drought Tolerance

    Yan Liang

    2013-11-01

    Full Text Available Drought is a major threat to agriculture production worldwide. Mitogen-activated protein kinases (MAPKs play a pivotal role in sensing and converting stress signals into appropriate responses so that plants can adapt and survive. To examine the function of MAPKs in the drought tolerance of tomato plants, we silenced the SpMPK1, SpMPK2, and SpMPK3 genes in wild-type plants using the virus-induced gene silencing (VIGS method. The results indicate that silencing the individual genes or co-silencing SpMPK1, SpMPK2, and SpMPK3 reduced the drought tolerance of tomato plants by varying degrees. Co-silencing SpMPK1 and SpMPK2 impaired abscisic acid (ABA-induced and hydrogen peroxide (H2O2-induced stomatal closure and enhanced ABA-induced H2O2 production. Similar results were observed when silencing SpMPK3 alone, but not when SpMPK1 and SpMPK2 were individually silenced. These data suggest that the functions of SpMPK1 and SpMPK2 are redundant, and they overlap with that of SpMPK3 in drought stress signaling pathways. In addition, we found that SpMPK3 may regulate H2O2 levels by mediating the expression of CAT1. Hence, SpMPK1, SpMPK2, and SpMPK3 may play crucial roles in enhancing tomato plants’ drought tolerance by influencing stomatal activity and H2O2 production via the ABA-H2O2 pathway.

  15. The APETALA-2-like transcription factor OsAP2-39 controls key interactions between abscisic acid and gibberellin in rice.

    Mahmoud W Yaish

    2010-09-01

    Full Text Available The interaction between phytohormones is an important mechanism which controls growth and developmental processes in plants. Deciphering these interactions is a crucial step in helping to develop crops with enhanced yield and resistance to environmental stresses. Controlling the expression level of OsAP2-39 which includes an APETALA 2 (AP2 domain leads to phenotypic changes in rice. Overexpression of OsAP2-39 leads to a reduction in yield by decreasing the biomass and the number of seeds in the transgenic rice lines. Global transcriptome analysis of the OsAP2-39 overexpression transgenic rice revealed the upregulation of a key abscisic acid (ABA biosynthetic gene OsNCED-I which codes for 9-cis-epoxycarotenoid dioxygenase and leads to an increase in the endogenous ABA level. In addition to OsNCED-1, the gene expression analysis revealed the upregulation of a gene that codes for the Elongation of Upper most Internode (EUI protein, an enzyme that catalyzes 16α, 17-epoxidation of non-13-hydroxylated GAs, which has been shown to deactivate gibberellins (GAs in rice. The exogenous application of GA restores the wild-type phenotype in the transgenic line and ABA application induces the expression of EUI and suppresses the expression of OsAP2-39 in the wild-type line. These observations clarify the antagonistic relationship between ABA and GA and illustrate a mechanism that leads to homeostasis of these hormones. In vivo and in vitro analysis showed that the expression of both OsNCED-1 and EUI are directly controlled by OsAP2-39. Together, these results reveal a novel mechanism for the control of the ABA/GA balance in rice which is regulated by OsAP2-39 that in turn regulates plant growth and seed production.

  16. Comparative Transcriptome Analysis Reveals the Influence of Abscisic Acid on the Metabolism of Pigments, Ascorbic Acid and Folic Acid during Strawberry Fruit Ripening.

    Dongdong Li

    Full Text Available A comprehensive investigation of abscisic acid (ABA biosynthesis and its influence on other important phytochemicals is critical for understanding the versatile roles that ABA plays during strawberry fruit ripening. Using RNA-seq technology, we sampled strawberry fruit in response to ABA or nordihydroguaiaretic acid (NDGA; an ABA biosynthesis blocker treatment during ripening and assessed the expression changes of genes involved in the metabolism of pigments, ascorbic acid (AsA and folic acid in the receptacles. The transcriptome analysis identified a lot of genes differentially expressed in response to ABA or NDGA treatment. In particular, genes in the anthocyanin biosynthesis pathway were actively regulated by ABA, with the exception of the gene encoding cinnamate 4-hydroxylase. Chlorophyll degradation was accelerated by ABA mainly owing to the higher expression of gene encoding pheide a oxygenase. The decrease of β-carotene content was accelerated by ABA treatment and delayed by NDGA. A high negative correlation rate was found between ABA and β-carotene content, indicating the importance of the requirement for ABA synthesis during fruit ripening. In addition, evaluation on the folate biosynthetic pathway indicate that ABA might have minor function in this nutrient's biosynthesis process, however, it might be involved in its homeostasis. Surprisingly, though AsA content accumulated during fruit ripening, expressions of genes involved in its biosynthesis in the receptacles were significantly lower in ABA-treated fruits. This transcriptome analysis expands our understanding of ABA's role in phytochemical metabolism during strawberry fruit ripening and the regulatory mechanisms of ABA on these pathways were discussed. Our study provides a wealth of genetic information in the metabolism pathways and may be helpful for molecular manipulation in the future.

  17. OsDMI3 Is a Novel Component of Abscisic Acid Signaling in the Induction of Antioxidant Defense in Leaves of Rice

    Ben Shi; Lan Ni; Aying Zhang; Jianmei Cao; Hong Zhang; Tingting Qin; Mingpu Tan; Jianhua Zhang; Mingyi Jiang

    2012-01-01

    Ca2+ and calmodulin (CaM) have been shown to play an important role in abscisic acid (ABA)-induced antioxidant defense.However,it is unknown whether Ca2+/CaM-dependent protein kinase (CCaMK) is involved in the process.In the present study,the role of rice CCaMK,OsDMI3,in ABA-induced antioxidant defense was investigated in leaves of rice (Oryza sativa) plants.Treatments with ABA,H2O2,and polyethylene glycol (PEG) induced the expression of OsDMI3 and the activity of OsDMI3,and H2O2 is required for the ABA-induced increases in the expression and the activity of OsDMI3 under water stress.Subcellular localization analysis showed that OsDMI3 is located in the nucleus,the cytoplasm,and the plasma membrane.The analysis of the transient expression of OsDMI3 in rice protoplasts and the RNA interference (RNAi) silencing of OsDMI3 in rice protoplasts showed that OsDMI3 is required for ABA-induced increases in the expression and the activities of superoxide dismutase (SOD) and catalase (CAT).Further,the oxidative damage induced by higher concentrations of PEG and H2O2 was aggravated in the mutant of OsDMI3.Moreover,the analysis of the RNAi silencing of OsDMI3 in protoplasts and the mutant of OsDMI3 showed that higher levels of H2O2 accumulation require OsDMI3 activation in ABA signaling,but the initial H2O2 production induced by ABA is not dependent on the activation of OsDMI3 in leaves of rice plants.Our data reveal that OsDMI3 is an important component in ABA-induced antioxidant defense in rice.

  18. Gene expression and metabolite profiling of developing highbush blueberry fruit indicates transcriptional regulation of flavonoid metabolism and activation of abscisic acid metabolism.

    Zifkin, Michael; Jin, Alena; Ozga, Jocelyn A; Zaharia, L Irina; Schernthaner, Johann P; Gesell, Andreas; Abrams, Suzanne R; Kennedy, James A; Constabel, C Peter

    2012-01-01

    Highbush blueberry (Vaccinium corymbosum) fruits contain substantial quantities of flavonoids, which are implicated in a wide range of health benefits. Although the flavonoid constituents of ripe blueberries are known, the molecular genetics underlying their biosynthesis, localization, and changes that occur during development have not been investigated. Two expressed sequence tag libraries from ripening blueberry fruit were constructed as a resource for gene identification and quantitative real-time reverse transcription-polymerase chain reaction primer design. Gene expression profiling by quantitative real-time reverse transcription-polymerase chain reaction showed that flavonoid biosynthetic transcript abundance followed a tightly regulated biphasic pattern, and transcript profiles were consistent with the abundance of the three major classes of flavonoids. Proanthocyanidins (PAs) and corresponding biosynthetic transcripts encoding anthocyanidin reductase and leucoanthocyanidin reductase were most concentrated in young fruit and localized predominantly to the inner fruit tissue containing the seeds and placentae. Mean PA polymer length was seven to 8.5 subunits, linked predominantly via B-type linkages, and was relatively constant throughout development. Flavonol accumulation and localization patterns were similar to those of the PAs, and the B-ring hydroxylation pattern of both was correlated with flavonoid-3'-hydroxylase transcript abundance. By contrast, anthocyanins accumulated late in maturation, which coincided with a peak in flavonoid-3-O-glycosyltransferase and flavonoid-3'5'-hydroxylase transcripts. Transcripts of VcMYBPA1, which likely encodes an R2R3-MYB transcriptional regulator of PA synthesis, were prominent in both phases of development. Furthermore, the initiation of ripening was accompanied by a substantial rise in abscisic acid, a growth regulator that may be an important component of the ripening process and contribute to the regulation of

  19. Solanum lycopersicum IAA15 functions in the 2,4-dichlorophenoxyacetic acid herbicide mechanism of action by mediating abscisic acid signalling.

    Xu, Tao; Wang, Yanling; Liu, Xin; Gao, Song; Qi, Mingfang; Li, Tianlai

    2015-07-01

    2,4-Dichlorophenoxyacetic acid (2,4-D), an important plant growth regulator, is the herbicide most commonly used worldwide to control weeds. However, broad-leaf fruits and vegetables are extremely sensitive to herbicides, which can cause damage and result in lost crops when applied in a manner inconsistent with the directions. Despite detailed knowledge of the mechanism of 2,4-D, the regulation of auxin signalling is still unclear. For example, although the major mediators of auxin signalling, including auxin/indole acetic acid (AUX/IAA) proteins and auxin response factors (ARFs), are known to mediate auxinic herbicides, the underlying mechanisms are still unclear. In this study, the effects of 2,4-D on AUX/IAA gene expression in tomato were investigated, and the two most notably up-regulated genes, SlIAA15 and SlIAA29, were selected for further study. Western blotting revealed the substantial accumulation of both SlIAA15 and SlIAA29, and the expression levels of the corresponding genes were increased following abscisic acid (ABA) and ethylene treatment. Overexpressing SlIAA15, but not SlIAA29, induced a 2,4-D herbicide damage phenotype. The 35S::SlIAA15 line exhibited a strong reduction in leaf stomatal density and altered expression of some R2R3 MYB genes that are putatively involved in the regulation of stomatal differentiation. Further study revealed that root elongation in 35S::SlIAA15 was sensitive to ABA treatment, and was most probably due to the altered expression of an ABA signal transduction gene. In addition, the altered auxin sensitivities of SlIAA15 transformants were also explored. These results suggested that SlIAA15 plays an important role in determining the effects of the herbicide 2,4-D. PMID:25948703

  20. Release of GTP Exchange Factor Mediated Down-Regulation of Abscisic Acid Signal Transduction through ABA-Induced Rapid Degradation of RopGEFs

    Waadt, Rainer; Schroeder, Julian I.

    2016-01-01

    The phytohormone abscisic acid (ABA) is critical to plant development and stress responses. Abiotic stress triggers an ABA signal transduction cascade, which is comprised of the core components PYL/RCAR ABA receptors, PP2C-type protein phosphatases, and protein kinases. Small GTPases of the ROP/RAC family act as negative regulators of ABA signal transduction. However, the mechanisms by which ABA controls the behavior of ROP/RACs have remained unclear. Here, we show that an Arabidopsis guanine nucleotide exchange factor protein RopGEF1 is rapidly sequestered to intracellular particles in response to ABA. GFP-RopGEF1 is sequestered via the endosome-prevacuolar compartment pathway and is degraded. RopGEF1 directly interacts with several clade A PP2C protein phosphatases, including ABI1. Interestingly, RopGEF1 undergoes constitutive degradation in pp2c quadruple abi1/abi2/hab1/pp2ca mutant plants, revealing that active PP2C protein phosphatases protect and stabilize RopGEF1 from ABA-mediated degradation. Interestingly, ABA-mediated degradation of RopGEF1 also plays an important role in ABA-mediated inhibition of lateral root growth. The presented findings point to a PP2C-RopGEF-ROP/RAC control loop model that is proposed to aid in shutting off ABA signal transduction, to counteract leaky ABA signal transduction caused by “monomeric” PYL/RCAR ABA receptors in the absence of stress, and facilitate signaling in response to ABA. PMID:27192441

  1. Increased abscisic acid levels in transgenic maize overexpressing AtLOS5 mediated root ion fluxes and leaf water status under salt stress.

    Zhang, Juan; Yu, Haiyue; Zhang, Yushi; Wang, Yubing; Li, Maoying; Zhang, Jiachang; Duan, Liusheng; Zhang, Mingcai; Li, Zhaohu

    2016-03-01

    Abscisic acid (ABA) is a vital cellular signal in plants, and effective ABA signalling is pivotal for stress tolerance. AtLOS5 encoding molybdenum cofactor sulphurase is a key regulator of ABA biosynthesis. Here, transgenic AtLOS5 plants were generated to explore the role of AtLOS5 in salt tolerance in maize. AtLOS5 overexpression significantly up-regulated the expression of ZmVp14-2, ZmAO, and ZmMOCO, and increased aldehyde oxidase activities, which enhanced ABA accumulation in transgenic plants under salt stress. Concurrently, AtLOS5 overexpression induced the expression of ZmNHX1, ZmCBL4, and ZmCIPK16, and enhanced the root net Na(+) efflux and H(+) influx, but decreased net K(+) efflux, which maintained a high cytosolic K(+)/Na(+) ratio in transgenic plants under salt stress. However, amiloride or sodium orthovanadate could significantly elevate K(+) effluxes and decrease Na(+) efflux and H(+) influx in salt-treated transgenic roots, but the K(+) effluxes were inhibited by TEA, suggesting that ion fluxes regulated by AtLOS5 overexpression were possibly due to activation of Na(+)/H(+) antiport and K(+) channels across the plasma membrane. Moreover, AtLOS5 overexpression could up-regulate the transcripts of ZmPIP1:1, ZmPIP1:5, and ZmPIP2:4, and enhance root hydraulic conductivity. Thus transgenic plants had higher leaf water potential and turgor, which was correlated with greater biomass accumulation under salt stress. Thus AtLOS5 overexpression induced the expression of ABA biosynthetic genes to promote ABA accumulation, which activated ion transporter and PIP aquaporin gene expression to regulate root ion fluxes and water uptake, thus maintaining high cytosolic K(+) and Na(+) homeostasis and better water status in maize exposed to salt stress. PMID:26743432

  2. Phosphorylation of serine residue modulates cotton Di19-1 and Di19-2 activities for responding to high salinity stress and abscisic acid signaling

    Qin, Li-Xia; Nie, Xiao-Ying; Hu, Rong; Li, Gang; Xu, Wen-Liang; Li, Xue-Bao

    2016-01-01

    Di19 (drought-induced protein 19) family is a novel type of Cys2/His2 zinc-finger proteins. In this study, we demonstrated that cotton Di19-1 and Di19-2 (GhDi19-1/-2) proteins could be phosphorylated in vitro by the calcium-dependent protein kinase (CDPK). Mutation of Ser to Ala in N-terminus of GhDi19-1/-2 led to the altered subcellular localization of the two proteins, but the constitutively activated form (Ser was mutated to Asp) of GhDi19-1/-2 still showed the nuclear localization. GhDi19-1/-2 overexpression transgenic Arabidopsis seedlings displayed the hypersensitivity to high salinity and abscisic acid (ABA). However, Ser site-mutated GhDi19-1(S116A) and GhDi19-2(S114A), and Ser and Thr double sites-mutated GhDi19-1(S/T-A/A) and GhDi19-2(S/T-A/A) transgenic Arabidopsis did not show the salt- and ABA-hypersensitive phenotypes. In contrast, overexpression of Thr site-mutated GhDi19-1(T114A) and GhDi19-2(T112A) in Arabidopsis still resulted in salt- and ABA-hypersensitivity phenotypes, like GhDi19-1/-2 transgenic lines. Overexpression of GhDi19-1/-2 and their constitutively activated forms in Atcpk11 background could recover the salt- and ABA-insensitive phenotype of the mutant. Thus, our results demonstrated that Ser phosphorylation (not Thr phosphorylation) is crucial for functionally activating GhDi19-1/-2 in response to salt stress and ABA signaling during early plant development, and GhDi19-1/-2 proteins may be downstream targets of CDPKs in ABA signal pathway. PMID:26829353

  3. Expression of Stipa purpurea SpCIPK26 in Arabidopsis thaliana Enhances Salt and Drought Tolerance and Regulates Abscisic Acid Signaling

    Zhou, Yanli; Sun, Xudong; Yang, Yunqiang; Li, Xiong; Cheng, Ying; Yang, Yongping

    2016-01-01

    Stipa purpurea (S. purpurea) is the dominant plant species in the alpine steppe of the Qinghai-Tibet Plateau, China. It is highly resistant to cold and drought conditions. However, the underlying mechanisms regulating the stress tolerance are unknown. In this study, a CIPK gene from S. purpurea (SpCIPK26) was isolated. The SpCIPK26 coding region consisted of 1392 bp that encoded 464 amino acids. The protein has a highly conserved catalytic structure and regulatory domain. The expression of SpCIPK26 was induced by drought and salt stress. SpCIPK26 overexpression in Arabidopsis thaliana (A. thaliana) plants provided increased tolerance to drought and salt stress in an abscisic acid (ABA)-dependent manner. Compared with wild-type A. thaliana plants, SpCIPK26-overexpressing plants had higher survival rates, water potentials, and photosynthetic efficiency (Fv/Fm), as well as lower levels of reactive oxygen species (ROS) following exposure to drought and salt stress. Gene expression analyses indicated stress-inducible genes (RD29A, RD29B, and ABF2) and a ROS-scavenger gene (CAT1) were upregulated in SpCIPK26-overexpressing plants after stress treatments. All of these marker genes are associated with ABA-responsive cis-acting elements. Additionally, the similarities in the gene expression patterns following ABA, mannitol, and NaCl treatments suggest SpCIPK26 has an important role during plant responses to drought and salt stress and in regulating ABA signaling. PMID:27338368

  4. Changes in the levels of abscisic acid and its metabolites in excised leaf blades of Xanthium strumarium during and after water stress

    Zeevaart, J.A.D.

    1980-10-01

    The time course of abscisic acid (ABA) accumulation during water stress and of degradation following rehydration was investigated by analyzing the levels of ABA and its metabolites phaseic acid (PA) and alkalihydrolyzable conjugated ABA in excised leaf blades of Xanthium strumarium. Initial purification was by reverse-phase, preparative, high performance liquid chromatography (HPLC) which did not require prior partitioning. ABA and PA were purified further by analytical HPLC with a ..mu..Bondapak-NH/sub 2/ column, and quantified by GLC with an electron capture detector. The ABA content of stressed leaves increased for 4 to 5 hours and then leveled off due to a balance between synthesis and degradation. Since PA accumulated at a constant rate throughout the wilting period, it was concluded that the rate of ABA synthesis decreased after the first 4 to 5 hours stress. Conjugated ABA increased at a low rate during stress. This is interpreted to indicate that free ABA was converted to the conjugated form, rather than the reverse. Following rehydration of wilted leaves, the ABA level immediately ceased increasing; it remained constant for 1 hour and then declined rapidly to the prestress level over a 2- to 3-hour period with a concomitant rise in the PA level. In contrast to the rapid disappearance of ABA after relief of stress, the high PA content of rehydrated leaves declined only slowly. The level of conjugated ABA did not change following rehydration, indicating that conjugation of ABA was irreversible. Detached Xanthium leaves that were subjected to a wilting-recovery-rewilting cycle in darkness responded to the second wilting period by formation of the same amount of ABA as accumulated after the first stress period.

  5. The upregulation of thiamine (vitamin B1 biosynthesis in Arabidopsis thaliana seedlings under salt and osmotic stress conditions is mediated by abscisic acid at the early stages of this stress response

    Rapala-Kozik Maria

    2012-01-01

    Full Text Available Abstract Background Recent reports suggest that vitamin B1 (thiamine participates in the processes underlying plant adaptations to certain types of abiotic and biotic stress, mainly oxidative stress. Most of the genes coding for enzymes involved in thiamine biosynthesis in Arabidopsis thaliana have been identified. In our present study, we examined the expression of thiamine biosynthetic genes, of genes encoding thiamine diphosphate-dependent enzymes and the levels of thiamine compounds during the early (sensing and late (adaptation responses of Arabidopsis seedlings to oxidative, salinity and osmotic stress. The possible roles of plant hormones in the regulation of the thiamine contribution to stress responses were also explored. Results The expression of Arabidopsis genes involved in the thiamine diphosphate biosynthesis pathway, including that of THI1, THIC, TH1 and TPK, was analyzed for 48 h in seedlings subjected to NaCl or sorbitol treatment. These genes were found to be predominantly up-regulated in the early phase (2-6 h of the stress response. The changes in these gene transcript levels were further found to correlate with increases in thiamine and its diphosphate ester content in seedlings, as well as with the enhancement of gene expression for enzymes which require thiamine diphosphate as a cofactor, mainly α-ketoglutarate dehydrogenase, pyruvate dehydrogenase and transketolase. In the case of the phytohormones including the salicylic, jasmonic and abscisic acids which are known to be involved in plant stress responses, only abscisic acid was found to significantly influence the expression of thiamine biosynthetic genes, the thiamine diphosphate levels, as well as the expression of genes coding for main thiamine diphosphate-dependent enzymes. Using Arabidopsis mutant plants defective in abscisic acid production, we demonstrate that this phytohormone is important in the regulation of THI1 and THIC gene expression during salt stress

  6. AtPP2CG1, a protein phosphatase 2C, positively regulates salt tolerance of Arabidopsis in abscisic acid-dependent manner

    Liu, Xin, E-mail: fangfei6073@126.com [Plant Bioengineering Laboratory, Northeast Agricultural University, Harbin 150030 (China); Zhu, Yanming, E-mail: ymzhu2001@neau.edu.cn [Plant Bioengineering Laboratory, Northeast Agricultural University, Harbin 150030 (China); Zhai, Hong, E-mail: Zhai.h@neigaehrb.ac.cn [Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Harbin 150040 (China); Cai, Hua, E-mail: small-big@sohu.com [Plant Bioengineering Laboratory, Northeast Agricultural University, Harbin 150030 (China); Ji, Wei, E-mail: iwei_j@hotmail.com [Plant Bioengineering Laboratory, Northeast Agricultural University, Harbin 150030 (China); Luo, Xiao, E-mail: luoxiao2010@yahoo.cn [Plant Bioengineering Laboratory, Northeast Agricultural University, Harbin 150030 (China); Li, Jing, E-mail: lijing@neau.edu.cn [Plant Secondary Metabolism Laboratory, Northeast Agricultural University, Harbin 150030 (China); Bai, Xi, E-mail: baixi@neau.edu.cn [Plant Bioengineering Laboratory, Northeast Agricultural University, Harbin 150030 (China)

    2012-06-15

    Highlights: Black-Right-Pointing-Pointer AtPP2CG1 positively regulates salt tolerance in ABA-dependent manner. Black-Right-Pointing-Pointer AtPP2CG1 up-regulates the expression of marker genes in different pathways. Black-Right-Pointing-Pointer AtPP2CG1 expresses in the vascular system and trichomes of Arabidopsis. -- Abstract: AtPP2CG1 (Arabidopsis thaliana protein phosphatase 2C G Group 1) was predicted as an abiotic stress candidate gene by bioinformatic analysis in our previous study. The gene encodes a putative protein phosphatase 2C that belongs to Group G of PP2C. There is no report of Group G genes involved in abiotic stress so far. Real-time RT-PCR analysis showed that AtPP2CG1 expression was induced by salt, drought, and abscisic acid (ABA) treatment. The expression levels of AtPP2CG1 in the ABA synthesis-deficient mutant abi2-3 were much lower than that in WT plants under salt stress suggesting that the expression of AtPP2CG1 acts in an ABA-dependent manner. Over-expression of AtPP2CG1 led to enhanced salt tolerance, whereas its loss of function caused decreased salt tolerance. These results indicate that AtPP2CG1 positively regulates salt stress in an ABA-dependent manner. Under salt treatment, AtPP2CG1 up-regulated the expression levels of stress-responsive genes, including RD29A, RD29B, DREB2A and KIN1. GUS activity was detected in roots, leaves, stems, flower, and trichomes of AtPP2CG1 promoter-GUS transgenic plants. AtPP2CG1 protein was localized in nucleus and cytoplasm via AtPP2CG1:eGFP and YFP:AtPP2CG1 fusion approaches.

  7. Language and development in FG syndrome with callosal agenesis.

    McCardle, P; Wilson, B

    1993-06-01

    The FG syndrome is characterized by unusual facies, sudden infant death, developmental delay, and abnormalities of the cardiac, gastrointestinal, and central nervous systems. No longitudinal data on development in surviving patients are currently available. Serial evaluations of a patient with FG syndrome, whose sole central nervous system anomaly was agenesis of the corpus callosum, showed a consistent pattern over time. Specific language impairments in syntactic and pragmatic-semantic areas are emerging. These findings represent the first detailed data on which expectations for children with the FG syndrome can be based. The findings also fit theoretical constructs on the function of the corpus callosum and may therefore be generalized to provide expectations for other patients with isolated agenesis of the corpus callosum. Given the information gained from this case, it is clear that language intervention/consultation should be a pivotal service for such children, and that the speech-language pathologist should play a role in the development of an integrated educational services plan. PMID:7688382

  8. Fulvic Acid Mediated Photolysis of Ibuprofen in Water.

    Photolysis of the nonsteroidal anti-inflammatory drug ibuprofen was studied in solutions of fulvic acid (FA) isolated from Pony Lake, Antarctica; Suwannee River, GA, USA; and Old Woman Creek, OH, USA. At an initial concentration of 10 µM ibuprofen degrades by direct photolysis...

  9. [Free fatty acids: mediators of insulin resistance and atherosclerosis].

    Castro Cabezas, M; Erkelens, D W; van Dijk, H

    2002-01-19

    Free fatty acids (FFAs) are involved in the transportation of energy; in the postprandial phase to the peripheral tissues and in the postabsorptive phase from the adipose tissue to the liver. In the postprandial phase, FFAs are mainly derived from hydrolysis of triglyceride-rich particles like chylomicrons and very low-density lipoproteins (VLDL). The flux of FFAs is directed to peripheral cells such as adipocytes and muscle cells. In the postabsorptive period, FFAs are transported to the liver after being released from intracellular storage in the adipocytes. Complement component 3 (C3) plays an important role in the uptake of free fatty acids by the peripheral cells and their esterification to triglycerides. Since C3 is also involved in the pathogenesis of the insulin resistance syndrome, and since a deviant FFA metabolism with an increased FFA flux to the liver may induce insulin resistance, it is hypothesized that C3 may form the missing link between FFA metabolism and insulin resistance. In addition, recent studies have increasingly indicated that atherosclerosis is in fact an inflammation-based process involving complement-dependent responses, in which FFAs seem to play a role in the complement-dependent pathway. It has recently become apparent that FFAs have a regulatory function in the transcription of DNA, in relation to lipoprotein metabolism. This is where PPAR-gamma and PPAR-alpha agonists ('glitazones' and fibrates respectively) are active (PPAR is an abbreviation for peroxisome proliferation activating receptor). Glitazons may play an important role in the treatment of insulin resistance and related disorders. Acquiring more knowledge about the relationship between complement and FFA metabolism may increase our understanding of these processes and provide openings for the development of new antiatherogenic strategies. PMID:11826668

  10. Retinoic Acid-mediated Nuclear Receptor Activation and Hepatocyte Proliferation

    Bushue, Nathan; Wan, Yu-Jui Yvonne

    2016-01-01

    Due to their well-known differentiation and apoptosis-inducing abilities, retinoic acid (RA) and its analogs have strong anti-cancer efficacy in human cancers. However, in vivo RA is a liver mitogen. While speculation has persisted that RA-mediated signaling is likely involved in hepatocyte proliferation during liver regeneration, direct evidence is still required. Findings in support of this proposition include observations that a release of retinyl palmitate (the precursor of RA) occurs in liver stellate cells following liver injury. Nevertheless, the biological action of this released vitamin A is virtually unknown. More likely is that the released vitamin A is converted to RA, the biological form, and then bound to a specific receptor (retinoid x receptor; RXRα), which is most abundantly expressed in the liver. Considering the mitogenic effects of RA, the RA-activated RXRα would likely then influence hepatocyte proliferation and liver tissue repair. At present, the mechanism by which RA stimulates hepatocyte proliferation is largely unknown. This review summarizes the activation of nuclear receptors (peroxisome proliferator activated receptor-α, pregnane x receptor, constitutive androstane receptor, and farnesoid x receptor) in an RXRα dependent manner to induce hepatocyte proliferation, providing a link between RA and its proliferative role.

  11. New insights into the acid mediated disproportionation of pentavalent uranyl

    Mougel, Victor; Biswas, Biplab; Pecaut, Jacques; Mazzanti, Marinella [Laboratoire de Reconnaissance Ionique et Chimie de Coordination, SCIB, UMR-E 3 CEA-UJF FRE 3200 CNRS, INAC, CEA-Grenoble, 17 rue des Martyrs, 38054 Grenoble Cedex 09 (France)

    2010-07-01

    The reaction of benzoic acid with the uranyl(V) complex [(UO{sub 2}Py{sub 5})(KI{sub 2}Py{sub 2})] in pyridine leads to immediate disproportionation with formation of a hexa-nuclear U(IV) benzoate cluster, a bis-benzoate complex of uranyl(VI) and water. (authors)

  12. ORA47 (octadecanoid-responsive AP2/ERF-domain transcription factor 47) regulates jasmonic acid and abscisic acid biosynthesis and signaling through binding to a novel cis-element.

    Chen, Hsing-Yu; Hsieh, En-Jung; Cheng, Mei-Chun; Chen, Chien-Yu; Hwang, Shih-Ying; Lin, Tsan-Piao

    2016-07-01

    ORA47 (octadecanoid-responsive AP2/ERF-domain transcription factor 47) of Arabidopsis thaliana is an AP2/ERF domain transcription factor that regulates jasmonate (JA) biosynthesis and is induced by methyl JA treatment. The regulatory mechanism of ORA47 remains unclear. ORA47 is shown to bind to the cis-element (NC/GT)CGNCCA, which is referred to as the O-box, in the promoter of ABI2. We proposed that ORA47 acts as a connection between ABA INSENSITIVE1 (ABI1) and ABI2 and mediates an ABI1-ORA47-ABI2 positive feedback loop. PORA47:ORA47-GFP transgenic plants were used in a chromatin immunoprecipitation (ChIP) assay to show that ORA47 participates in the biosynthesis and/or signaling pathways of nine phytohormones. Specifically, many abscisic acid (ABA) and JA biosynthesis and signaling genes were direct targets of ORA47 under stress conditions. The JA content of the P35S:ORA47-GR lines was highly induced under wounding and moderately induced under water stress relative to that of the wild-type plants. The wounding treatment moderately increased ABA accumulation in the transgenic lines, whereas the water stress treatment repressed the ABA content. ORA47 is proposed to play a role in the biosynthesis of JA and ABA and in regulating the biosynthesis and/or signaling of a suite of phytohormone genes when plants are subjected to wounding and water stress. PMID:26974851

  13. Effect of 5-aminolevulinic acid-mediated photodynamic therapy on human gastric cancer xenografts in nude mice in vivo%5-氨基乙酰丙酸介导的光动力学对裸鼠人胃癌移植瘤的治疗作用

    周广军; 黄宗海; 俞金龙; 厉周; 丁涟沭

    2008-01-01

    Objective To investigate the effect of 5-aminolevulinic acid (ALA)-mediated photodynamic therapy (PDT) on human gastric cancer xenografts in vivo and to explore its potential tumoreidal mechanism. Methods Cultured MGC-803 human gastric cancer cells were injected below the skins of the nude mice to develop the tumor model. The tumor-bearing nude mice were examined under the Leica LT-9MACIMSYSPULS to detect the fluorescence. The tumor volume of day 1, 3, 7, 14, 21 after treatment were measured, and its histological changes were also studied. The tissues of the tumors in nude mice of the control group, light group, 5-ALA group and PDT group were examined with the electron microscope and apoptosis was detected by TUNEL assay. Results The tumor model was successfully developed. The tumor in the nude mice emited the red fluorescence under the Leica LT-9MACIMSYSPULS. The tumor volumes were (0.189±0.010)cm3, (0.183±0.011)cm3, (0.185±0.019) cm3, (0.182±0.015)cm3 for the control group, light group, 5-ALA group, PDT group, respectively at day 1 after treatment, while at day 3, (0.294±0.010)cm3, (0.280±0.013)cm3, (0.278±0.016)cm3, (0.183±0.014)cm3;at day 7, (0.409±0.016)cm3, (0.411±0.009)cm3, (0.407±0.015)cm3, (0.221±0.008)cm3;at day 14, (0.970±0.055)cm3 (0.976±0.054)cm3, (0.981±0.032)cm3, (0.318±0.005)cm3;at day 21, (1.495±0.059)cm3, (1.513±0.057)cm3, ( 1.524±0.063)cm3, (0.446±0.042)cm3(F=1003.086, P=0.000). The histology demonstrated that most tumor blood vessels were congested and necrosis developed after PDT while not in the control group, light group and 5-ALA group. Necrosis and apoptosis were observed in the cells of the tumors of the PDT group examined by TUNEL and electron microscope while not in the cells of the tumors of the other groups. Conclusions 5-aminolevulinic acid-mediated photodynamic therapy (PDT) can induce injury to human gastric cancer xenografts and inhibit the tumor growth while light only and 5-ALA only can not. 5-aminolevulinic

  14. Cloning of 9-cis-epoxycarotenoid dioxygenase (NCED) gene encoding a key enzyme during abscisic acid (ABA) biosynthesis and ABA-regulated ethylene production in detached young persimmon calyx

    LENG Ping; ZHANG GuangLian; LI XiangXin; WANG LiangHe; ZHENG ZhongMing

    2009-01-01

    Unlike the typical climacteric fruits,persimmons (Diospyros kaki Thunb.) produce higher levels of ethylene when they are detached from trees at a younger stage.In order to obtain detailed information on the role of abscisic acid (ABA) in ripening,we cloned the DKNCED1,DKACS2,and DKAC01 genes from the calyx.Water loss was first noted in the calyx lobe,and DKNCED1 was highly expressed 1 d after the fruits were detached,coinciding with an increase in the ABA content.Then,the DKACS2 and DKAC01 genes were expressed after some delay.In the calyx,the ABA peak was observed 2 d after the fruits were harvested,and this peak preceded the ethylene peak observed on day 3.The fruit firmness rapidly decreased on day 4,and the fruits softened completely 6 d after they were harvested.The increases in the expressions of ABA,ethylene,and the genes in the calyxes occurred earlier than the corresponding increases in the pulp,although the 3 increases occurred on different days.Exogenous ABA treatment increased ABA concentration,induced expression of both ACS and ACO,and promoted ethylene synthesis and young-fruit softening;by contrast,treatment with NDGA inhibited the gene expressions and ethylene synthesis and delayed young-fruit softening.These results indicate that ethylene biosynthesis in the detached young persimmon fruits is initially triggered by ABA,which is induced by water loss in the calyx,through the induction of DKACS2 and DKAC01 expressions.The ethylene produced in the calyx subsequently diffuses into the pulp tissue,where it induces autocatalytic ethylene biosynthesis,resulting in an abrupt increase in ethylene production.

  15. A link between magnesium-chelatase H subunit and sucrose nonfermenting 1 (SNF1)-related protein kinase SnRK2.6/OST1 in Arabidopsis guard cell signalling in response to abscisic acid.

    Liang, Shan; Lu, Kai; Wu, Zhen; Jiang, Shang-Chuan; Yu, Yong-Tao; Bi, Chao; Xin, Qi; Wang, Xiao-Fang; Zhang, Da-Peng

    2015-10-01

    Magnesium-chelatase H subunit [CHLH/putative abscisic acid (ABA) receptor ABAR] positively regulates guard cell signalling in response to ABA, but the molecular mechanism remains largely unknown. A member of the sucrose nonfermenting 1 (SNF1)-related protein kinase 2 family, SnRK2.6/open stomata 1 (OST1)/SRK2E, which plays a critical role in ABA signalling in Arabidopsis guard cells, interacts with ABAR/CHLH. Neither mutation nor over-expression of the ABAR gene affects significantly ABA-insensitive phenotypes of stomatal movement in the OST1 knockout mutant allele srk2e. However, OST1 over-expression suppresses ABA-insensitive phenotypes of the ABAR mutant allele cch in stomatal movement. These genetic data support that OST1 functions downstream of ABAR in ABA signalling in guard cells. Consistent with this, ABAR protein is phosphorylated, but independently of the OST1 protein kinase. Two ABAR mutant alleles, cch and rtl1, show ABA insensitivity in ABA-induced reactive oxygen species and nitric oxide production, as well as in ABA-activated phosphorylation of a K(+) inward channel KAT1 in guard cells, which is consistent with that observed in the pyr1 pyl1 pyl2 pyl4 quadruple mutant of the well-characterized ABA receptor PYR/PYL/RCAR family acting upstream of OST1. These findings suggest that ABAR shares, at least in part, downstream signalling components with PYR/PYL/RCAR receptors for ABA in guard cells; though cch and rtl1 show strong ABA-insensitive phenotypes in both ABA-induced stomatal closure and inhibition of stomatal opening, while the pyr1 pyl1 pyl2 pyl4 quadruple mutant shows strong ABA insensitivity only in ABA-induced stomatal closure. These data establish a link between ABAR/CHLH and SnRK2.6/OST1 in guard cell signalling in response to ABA. PMID:26175350

  16. The nitrate transporter MtNPF6.8 (MtNRT1.3) transports abscisic acid and mediates nitrate regulation of primary root growth in Medicago truncatula.

    Pellizzaro, Anthoni; Clochard, Thibault; Cukier, Caroline; Bourdin, Céline; Juchaux, Marjorie; Montrichard, Françoise; Thany, Steeve; Raymond, Valérie; Planchet, Elisabeth; Limami, Anis M; Morère-Le Paven, Marie-Christine

    2014-12-01

    Elongation of the primary root during postgermination of Medicago truncatula seedlings is a multigenic trait that is responsive to exogenous nitrate. A quantitative genetic approach suggested the involvement of the nitrate transporter MtNPF6.8 (for Medicago truncatula NITRATE TRANSPORTER1/PEPTIDE TRANSPORTER Family6.8) in the inhibition of primary root elongation by high exogenous nitrate. In this study, the inhibitory effect of nitrate on primary root elongation, via inhibition of elongation of root cortical cells, was abolished in npf6.8 knockdown lines. Accordingly, we propose that MtNPF6.8 mediates nitrate inhibitory effects on primary root growth in M. truncatula. pMtNPF6.8:GUS promoter-reporter gene fusion in Agrobacterium rhizogenes-generated transgenic roots showed the expression of MtNPF6.8 in the pericycle region of primary roots and lateral roots, and in lateral root primordia and tips. MtNPF6.8 expression was insensitive to auxin and was stimulated by abscisic acid (ABA), which restored the inhibitory effect of nitrate in npf6.8 knockdown lines. It is then proposed that ABA acts downstream of MtNPF6.8 in this nitrate signaling pathway. Furthermore, MtNPF6.8 was shown to transport ABA in Xenopus spp. oocytes, suggesting an additional role of MtNPF6.8 in ABA root-to-shoot translocation. (15)NO3(-)-influx experiments showed that only the inducible component of the low-affinity transport system was affected in npf6.8 knockdown lines. This indicates that MtNPF6.8 is a major contributor to the inducible component of the low-affinity transport system. The short-term induction by nitrate of the expression of Nitrate Reductase1 (NR1) and NR2 (genes that encode two nitrate reductase isoforms) was greatly reduced in the npf6.8 knockdown lines, supporting a role of MtNPF6.8 in the primary nitrate response in M. truncatula. PMID:25367858

  17. TOPOISOMERASE 6B is involved in chromatin remodelling associated with control of carbon partitioning into secondary metabolites and cell walls, and epidermal morphogenesis in Arabidopsis

    Mittal, Amandeep; Balasubramanian, Rajagopal; Cao, Jin; Singh, Prabhjeet; Subramanian, Senthil; Hicks, Glenn; Eugene A Nothnagel; Abidi, Noureddine; Janda, Jaroslav; Galbraith, David W; Rock, Christopher D.

    2014-01-01

    Plant growth is continuous and modular, a combination that allows morphogenesis by cell division and elongation and serves to facilitate adaptation to changing environments. The pleiotropic phenotypes of the harlequin (hlq) mutant, isolated on the basis of ectopic expression of the abscisic acid (ABA)- and auxin-inducible proDc3:GUS reporter gene, were previously characterized. Mutants are skotomorphogenic, have deformed and collapsed epidermal cells which accumulate callose and starch, cell ...

  18. EL ÁCIDO ABSCÍSICO ACELERA EL DESARROLLO FLORAL DE SOLIDAGO EN DÍAS CORTOS ABSCISIC ACID SPEED UP FLORAL DEVELOPMENT OF SOLIDAGO UNDER SHORT DAYS

    Víctor Julio Flórez Roncancio

    2009-06-01

    Full Text Available Solidago x luteus (M. L. Greene Broulliet y Semple (= x Solidaster hybridus, x S. luteus es una planta que responde a días cortos (DC para el desarrollo floral. En este proceso se ha establecido la participación de varias fitohormonas, entre éstas, la presencia del ácido abscísico (ABA en zonas y periodos específicos durante el desarrollo de la flor lo cual sugiere su acción promotora en la velocidad de antesis floral de esta especie en DC. En este trabajo se buscaron nuevos indicios de la participación de fitohormonas presentes en la fracción ácida con el proceso de floración. En una primera etapa, extractos foliares provenientes de hojas de plantas en días largos (caracterizadas por menor velocidad de antesis floral se aplicaron en botones florales de plantas en días cortos (caracterizadas por una mayor velocidad de antesis floral. Se realizaron ocho aplicaciones con diferentes frecuencias totalizando un periodo de tratamiento de 25 días. Los resultados mostraron que las sustancias presentes en los extractos de la fracción ácida, no alteran la velocidad promedio de antesis floral en los botones florales de plantas en DC. En la segunda etapa del experimento, la cuantificación de los extractos por ELISA, permitió establecer una mayor concentración de ABA en los extractos de hojas y de botones florales de plantas en DC y de botones florales en el inicio del tratamiento. Estos resultados confirman la relación del ABA con la mayor velocidad de antesis floral en plantas de Solidago x luteus en condiciones de DC.Solidago x luteus (M.L. Greene Broulliet & Semple (= x Solidaster hybridus, x S. luteus is a plant that respond to short days (SD for flower development. In this process, there has been established the involvement of many phytohormones, between these, the presence of the abscisic acid (ABA in zones and specific periods during flower development, suggests its promoter roll on the floral anthesis period of this species under

  19. 枸杞脱落酸生物合成关键酶基因NCED的克隆及表达分析%Cloning and Characterization of 9-cis-epoxycarotenoid Dioxygenase Gene(NCED) Encoding a Key Enzyme during Abscisic Acid Biosynthesis in Lycium barbarum L.

    陆平; 田跃胜; 王名雪; 李杉; 赵静雅

    2013-01-01

    Abscisic acid(ABA) regulates the essential physiological and developmental processes of plants and plays imporant roles in plant responses to various environmental stresses. 9-cis-epoxycarotenoid dioxygenase ( NCED)is the key regulatory enzyme in the biosynthesis pathway of ABA in higher plants. In the study,a full-lengh cDNA of NCED gene( LbNCED) was fristly isolated and characterized from the leaves of L. barbarum. LbNCED was 2316 bp, containing a 1824 bp ORF and encoding 607 amino acids. Comparative and bioinformatics analysis revealed that the homology amino acid sequence of Lycopersicon esculentum and Solarium tuberosum LbNCED was 90%. At the N-terminus of the LbNCED located a 15 amino acids putative chloroplast transit peptide. Southern blot analysis revealed that it was a low-copy gene in the genome of L. barbarum. Real-time Quantitative PCR ( RT-QPCR) analysis showed that LbNCED mRNA most abundantly accumulated in leaves. The RT-QPCR analysis revealed that dehydration and salt stress signficantly enhanced LbNCED transcript expression and ABA content accumulation.%脱落酸(abscisic acid,ABA)对植物的生长发育具有独特的调控功能,并在植物适应逆境环境中发挥重要作用.9-顺式环氧类胡萝卜素双加氧酶(NCED)是高等植物中ABA生物合成途径的一个关键酶.根据GenBank中的植物NCED基因的同源序列设计简并引物,通过RT-PCR及RACE技术从枸杞叶片中克隆到1个编码NCED的基因,命名为LbNCED.其cDNA全长为2316 bp,含有1个1824 bp的开放阅读框,编码1个含607氨基酸残基,分子量为67.38 kDa、等电点(pI)为6.43的假定蛋白,其氨基酸序列与番茄(Lycopersicon esculentum)和马铃薯(Solanum tuberosum)的同源性达90%,在N-末端具有1个含15个氨基酸的叶绿体转运肽.Southern杂交结果表明,该基因在枸杞基因组中以低拷贝形式存在.盐处理和脱水处理的枸杞叶片中LbNCED基因的表达与内源ABA的积累同步变化.

  20. Cannabis use and callosal white matter structure and integrity in recent-onset schizophrenia

    N. Dekker; N. Schmitz; B.D. Peters; T.A. van Amelsvoort; D.H. Linszen; L. de Haan

    2010-01-01

    Adolescent-onset cannabis use, compared with adult-onset use, has been associated with a higher risk for developing symptoms of schizophrenia-like psychotic disorders. To test the hypothesis that onset of cannabis use in early adolescence in male schizophrenia patients is associated with abnormaliti

  1. Age Differences in Interhemispheric Interactions: Callosal Structure, Physiological Function, and Behavior

    Fling, Brett W.; Peltier, Scott J.; Bo, Jin; Welsh, Robert C.; Seidler, Rachael D.

    2011-01-01

    There is a fundamental gap in understanding how brain structural and functional network connectivity are interrelated, how they change with age, and how such changes contribute to older adults’ sensorimotor deficits. Recent neuroimaging approaches including resting state functional connectivity MRI (fcMRI) and diffusion tensor imaging (DTI) have been used to assess brain functional (fcMRI) and structural (DTI) network connectivity, allowing for more integrative assessments of distributed neur...

  2. Early phenotype expression of cortical neurons: evidence that a subclass of migrating neurons have callosal axons.

    Schwartz, M. L.; Rakic, P.; Goldman-Rakic, P. S.

    1991-01-01

    The use of [3H]thymidine labeling in combination with various axonal transport tracers has revealed that a subset of migrating neurons in the fetal monkey cerebrum issue axons to the opposite cerebral hemisphere while still migrating to their final positions in the cortical plate. Other cortical neurons with the same "birthdate" (i.e., that underwent their last round of DNA synthesis on the same day) are not retrogradely labeled by tracer injections of the opposite hemisphere. These findings ...

  3. Callose-mediated resistance to pathogenic intruders in plant defense-related papillae

    Voigt, Christian A.

    2014-01-01

    Plants are exposed to a wide range of potential pathogens, which derive from diverse phyla. Therefore, plants have developed successful defense mechanisms during co-evolution with different pathogens. Besides many specialized defense mechanisms, the plant cell wall represents a first line of defense. It is actively reinforced through the deposition of cell wall appositions, so-called papillae, at sites of interaction with intruding microbial pathogens. The papilla is a complex structure that ...

  4. [A case of diagnostic dyspraxia without ideomotor apraxia by callosal lesion].

    Tei, H; Soma, Y; Uchiyama, S; Maruyama, S

    1993-05-01

    A case of diagnostic dyspraxia was reported. A 57-year-old right handed male had been suffering from the lack of cooperation between his right and left hands for six months. Except for decreased deep tendon reflexes in all extremities, there were no abnormal findings on neurological examination. On neuropsychological examination, he was attentive, well orientated and his spontaneous speech, comprehension, naming, repetition and reading were intact. There was peculiar dissociative behavior between his right and left hands. For instance, he put a cigarette or coin in the pocket with his right hand then his left hand took out and replaced them, and he buttoned his shirts with his right hand but then unbuttoned with his left hand. These left hand oppositional behavior to his right hand were triggered by voluntary activities of his right hand. Left unilateral agraphia was also revealed but ideomotor apraxia, compulsive manipulation of tools and grasp reflex were not demonstrated. T1-weighted MRI demonstrated irregular low signal intensity areas extending from the genu to the body of the corpus callosum. No definite lesion was detected in the medial aspect of the frontal lobe. Only small numbers of diagnostic dyspraxia have been reported and such cases without ideomotor apraxia or medial frontal lesion are even rare. MRI is very useful for detecting the lesion of the corpus callosum. PMID:8365065

  5. [Left unilateral melokinetic apraxia and left dynamic apraxia following partial callosal infarction].

    Verstichel, P; Meyrignac, C

    2000-03-01

    A 69 year-old right-handed man suffered from an infarct in the left anterior cerebral territory's artery, involving the anterior and middle parts of the corpus callosum, and the cingulum. He had a right crural hemiparesis with a grasp reflex of the right hand, and ipsilaterally a melokinetic and a dynamic apraxia. Agility of the left fingers was lost: fast and nimble movements of theses fingers, and repetitive gestures of the left hand were defective. Execution of motor sequences with the left hand was disrupted by a lack of litheness in gesture series. By analogy with unilateral left ideomotor apraxia, we suggest melokinetic and dynamic apraxia could be symptomatic of an interhemispheric disconnection. Premotor cortex could have a dominance for both digital movements and programmation of gestual sequences. As a general rule, the left cortex could be preferentially activated by the nature of some tasks, particularly the execution of complex gestual series, which implie an internal speech. In theses conditions, an interhemispheric disconnection could lead some difficulties to make theses gestures with the left hand. PMID:10740099

  6. Acid-mediated Lipinski’s second rule: application to drug design and targeting in cancer

    Omran, Ziad; Rauch, Cyril

    2014-01-01

    With a predicted 382.4 per 100,000 people expected to suffer from some form of malignant neoplasm by 2015, and a current death toll of 1 out of 8 deaths worldwide, improving treatment and/or drug design is an essential focus of cancer research. Multi-drug resistance is the leading cause of chemotherapeutic failure, and delivery of anticancer drugs to the inside of cancerous cells is another major challenge. Fifteen years ago, in a completely different field in which improving drug delivery is...

  7. Effects of 5-aminolevulinic acid-mediated sonodynamic therapy on macrophages

    Cheng J

    2013-02-01

    Full Text Available Jiali Cheng,1,* Xin Sun,1,2,* Shuyuan Guo,1,* Wei Cao,1 Haibo Chen,1 Yinghua Jin,1 Bo Li,1 Qiannan Li,1 Huan Wang,1 Zhu Wang,3 Qi Zhou,3 Peng Wang,3 Zhiguo Zhang,3 Wenwu Cao,3,4 Ye Tian1,21Division of Cardiology, the First Affiliated Hospital, Cardiovascular Institute, Harbin Medical University, Harbin, People’s Republic of China; 2Division of Pathophysiology, the State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Research, Ministry of Education, Harbin, People’s Republic of China; 3Laboratory of Photo- and Sono-theranostic Technologies and Condensed Matter Science and Technology Institute, Harbin Institute of Technology, Harbin, People’s Republic of China; 4Materials Research Institute, The Pennsylvania State University, University Park, PA, USA*These authors contributed equally to this workBackground: Inflammatory cells exhibit an elevated level of protoporphyrin IX (PpIX after the administration of 5-aminolevulinic acid (ALA. Here, we investigate the sonodynamic effects of ALA-derived PpIX (ALA-PpIX on macrophages, which are the pivotal inflammatory cells in atherosclerosis.Methods and results: Cultured THP-1 macrophages were incubated with ALA. Fluorescence microscope and fluorescence spectrometer detection showed that intracellular PpIX increased with the concentration of ALA in the incubation solution in a time dependent manner; the highest level of intracellular PpIX was observed after 3-hour incubation. 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide assays demonstrated that lower concentrations (less than 2 mM of ALA have no influence on cell viability (more than 90% of cells survived, but sonodynamic therapy (SDT with a low concentration of ALA significantly decreased the survival rate of cells, and the effect was increased with both ALA concentration and ultrasound exposure time. Cell apoptosis and necrosis induced by ALA-mediated SDT (ALA-SDT were measured using Hoechst 33258 and propidium iodide assay. ALA-SDT induced both cell apoptosis and necrosis, and the maximum apoptosis/necrosis ratio was observed at 6 hours after SDT with 1 mM of ALA and 5 minutes of ultrasound exposure. Flow cytometry analysis showed that ALA-SDT significantly increased late stage apoptotic cells (about 10-fold control. Furthermore, ALA-SDT induced reactive oxygen species generation in THP-1 macrophages immediately after the treatment and a conspicuous loss of mitochondrial membrane potential (MMP at 6 hours compared with that of the control, ALA alone, and ultrasound alone groups.Conclusion: ALA-SDT exhibited synergistic apoptotic effects on THP-1 macrophages, involving excessive intracellular reactive oxygen species generation and MMP loss. Therefore, ALA-SDT is a potential treatment for atherosclerosis.Keywords: 5-aminolevulinic acid, protoporphyrin IX, sonodynamic therapy, macrophage, atherosclerosis

  8. The Salicylic Acid-Mediated Release of Plant Volatiles Affects the Host Choice of Bemisia tabaci.

    Shi, Xiaobin; Chen, Gong; Tian, Lixia; Peng, Zhengke; Xie, Wen; Wu, Qingjun; Wang, Shaoli; Zhou, Xuguo; Zhang, Youjun

    2016-01-01

    The whitefly Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) causes serious crop losses worldwide by transmitting viruses. We have previously shown that salicylic acid (SA)-related plant defenses directly affect whiteflies. In this study, we applied exogenous SA to tomato plants in order to investigate the interaction between SA-induced plant volatiles and nonviruliferous B. tabaci B and Q or B- and Q-carrying tomato yellow leaf curl virus (TYLCV). The results showed that exogenous SA caused plants to repel nonviruliferous whiteflies, but the effect was reduced when the SA concentration was low and when the whiteflies were viruliferous. Exogenous SA increased the number and quantity of plant volatiles-especially the quantity of methyl salicylate and δ-limonene. In Y-tube olfactometer assays, methyl salicylate and δ-limonene repelled the whiteflies, but the repellency was reduced for viruliferous Q. We suggest that the release of plant volatiles as mediated by SA affects the interaction between whiteflies, plants, and viruses. Further studies are needed to determine why viruliferous Q is less sensitive than nonviruliferous Q to repellent plant volatiles. PMID:27376280

  9. Electrochemical oxidation of ascorbic acid mediated by carbon nano tubes/ Li+/ carbon paste modified solid electrode

    Multi-walled carbon nano tube (MWCNT) was used to modify BPPG electrode because of its unique structure and extraordinary properties. MWCNT modified electrode exhibited obvious enhancing and electro catalyzing effects to the oxidation of ascorbic acid using cyclic voltammetry technique. MWCNT was bonded on BPPG electrode surface using carbon paste with ratio of 30 % (w/ W) carbon paste (binder): 70 % (w/ w) MWCNT. This method of modification has lowered the capacitance background current and enabled lower detection limit of ascorbic acid concentration. The electrical conductivity property of MWCNT modified electrode was further improved with the intercalation with lithium ion and resulted in current enhancement of 2 times on the oxidation current of ascorbic acid. Parameters of pH and temperature showed significant relation to the sensitivity of MWCNT modified electrode. Under the optimized parameters, the calibration curve constructed was linear up from 50 μM to 5 mM with sensitivity of 34.5 mA M-1. The practical application of MWCNT modified electrode was demonstrated with Vitamin C pill and orange juice. Good reproducibility and recovery of ascorbic acid concentration showed the feasibility of MWCNT modified electrode to be used in the detection of ascorbic acid in aqueous solution. This also proposed MWCNT modified BPPG electrode possessed advantages such as low detection limit, high stability, low cost and simplicity in fabrication. (author)

  10. Acid mediates a prolonged antinociception via substance P signaling in acid-induced chronic widespread pain

    Chen, Wei-Nan; Chen, Chih-Cheng

    2014-01-01

    Background Substance P is an important neuropeptide released from nociceptors to mediate pain signals. We recently revealed antinociceptive signaling by substance P in acid-sensing ion channel 3 (ASIC3)-expressing muscle nociceptors in a mouse model of acid-induced chronic widespread pain. However, methods to specifically trigger the substance P antinociception were still lacking. Results Here we show that acid could induce antinociceptive signaling via substance P release in muscle. We preve...

  11. Production of phosphatidylcholine containing conjugated linoleic acid mediated by phospholipase A2

    Yamamoto, Yukihiro; Hosokawa, Masashi; Miyashita, Kazuo

    2006-01-01

    Esterification of lysophosphatidylcholine (LPC) with conjugated linoleic acid (CLA) was carried out using porcine pancreatic phospholipase A2 (PLA2). PLA2 only slightly synthesized phosphatidylcholine containing CLA (CLA-PC) at 2.6% by the addition of water. Addition of formamide in place of water markedly increased the yield of CLA-PC. In addition, synthesis of CLA-PC by PLA2 was affected by the amount of substrate CLA and PLA2 in the reaction system. Under optimal reaction conditions using ...

  12. Main Group Lewis Acid-Mediated Transformations of Transition-Metal Hydride Complexes.

    Maity, Ayan; Teets, Thomas S

    2016-08-10

    This Review highlights stoichiometric reactions and elementary steps of catalytic reactions involving cooperative participation of transition-metal hydrides and main group Lewis acids. Included are reactions where the transition-metal hydride acts as a reactant as well as transformations that form the metal hydride as a product. This Review is divided by reaction type, illustrating the diverse roles that Lewis acids can play in mediating transformations involving transition-metal hydrides as either reactants or products. We begin with a discussion of reactions where metal hydrides form direct adducts with Lewis acids, elaborating the structure and dynamics of the products of these reactions. The bulk of this Review focuses on reactions where the transition metal and Lewis acid act in cooperation, and includes sections on carbonyl reduction, H2 activation, and hydride elimination reactions, all of which can be promoted by Lewis acids. Also included is a section on Lewis acid-base secondary coordination sphere interactions, which can influence the reactivity of hydrides. Work from the past 50 years is included, but the majority of this Review focuses on research from the past decade, with the intent of showcasing the rapid emergence of this field and the potential for further development into the future. PMID:27164024

  13. Thyroid hormone receptor can modulate retinoic acid-mediated axis formation in frog embryogenesis.

    Banker, D E; Eisenman, R N

    1993-01-01

    Thyroid hormone receptor acts as a hormone-dependent transcriptional transactivator and as a transcriptional repressor in the absence of thyroid hormone. Specifically, thyroid hormone receptor can repress retinoic acid-induced gene expression through interactions with retinoic acid receptor. (Retinoic acid is a potent teratogen in the frog Xenopus laevis, acting at early embryonic stages to interfere with the formation of anterior structures. Endogenous retinoic acid is thought to act in norm...

  14. Hypochlorous acid-mediated oxidation of lipid components and antioxidants present in low-density lipoproteins

    Pattison, David I; Hawkins, Clare L; Davies, Michael Jonathan

    2003-01-01

    antioxidants are relatively ineffective as direct scavengers for HOCl as compared to water soluble antioxidants (e.g., ascorbate, k ca. 10(6) M(-)(1) s(-)(1)). The reaction of HOCl with hydroquinone (a simple model for ubiquinol-10) was also investigated both in aqueous solution (k = 45 M(-)(1) s(-)(1)) and in...... models compare well with experimental data and can be used to predict the effects of HOCl-mediated oxidation on LDL composition....

  15. β-aminobutyric acid mediated drought stress alleviation in maize (Zea mays L.).

    Shaw, Arun K; Bhardwaj, Pardeep K; Ghosh, Supriya; Roy, Sankhajit; Saha, Suman; Sherpa, Ang R; Saha, Samir K; Hossain, Zahed

    2016-02-01

    The present study highlights the role of β-aminobutyric acid (BABA) in alleviating drought stress effects in maize (Zea mays L.). Chemical priming was imposed by pretreating 1-week-old plants with 600 μM BABA prior to applying drought stress. Specific activities of key antioxidant enzymes and metabolites (ascorbate and glutathione) levels of ascorbate-glutathione cycle were studied to unravel the priming-induced modulation of plant defense system. Furthermore, changes in endogenous ABA and JA concentrations as well as mRNA expressions of key genes involved in their respective biosynthesis pathways were monitored in BABA-primed (BABA+) and non-primed (BABA-) leaves of drought-challenged plants to better understand the mechanistic insights into the BABA-induced hormonal regulation of plant response to water-deficit stress. Accelerated stomatal closure, high relative water content, and less membrane damage were observed in BABA-primed leaves under water-deficit condition. Elevated APX and SOD activity in non-primed leaves found to be insufficient to scavenge all H2O2 and O2 (·-) resulting in oxidative burst as evident after histochemical staining with NBT and DAB. A higher proline accumulation in non-primed leaves also does not give much protection against drought stress. Increased GR activity supported with the enhanced mRNA and protein expressions might help the BABA-primed plants to maintain a high GSH pool essential for sustaining balanced redox status to counter drought-induced oxidative stress damages. Hormonal analysis suggests that in maize, BABA-potentiated drought tolerance is primarily mediated through JA-dependent pathway by the activation of antioxidant defense systems while ABA biosynthesis pathway also plays an important role in fine-tuning of drought stress response. PMID:26416125

  16. ON THE PECULIARITIES OF THE RING CONTRACTION REACTIONS OF HOMODRIMANES VIA ACID MEDIATED EPOXIDE REARRANGEMENT

    Veaceslav Kulciţki

    2011-06-01

    Full Text Available A selective rearrangement of a epoxy-homodrimanic substrate is described. Using fluorosulfonic acid at low temperature leads by ring contraction to a perhydrindanic structure. On the contrary, using boron trifluoride-diethyl ether at r.t. selectively brings about angular methyl migration.

  17. Precision microbiome reconstitution restores bile acid mediated resistance to Clostridium difficile

    Buffie, Charlie G.; Bucci, Vanni; Stein, Richard R.; McKenney, Peter T.; Ling, Lilan; Gobourne, Asia; No, Daniel; Liu, Hui; Kinnebrew, Melissa; Viale, Agnes; Littmann, Eric; van den Brink, Marcel R. M.; Jenq, Robert R.; Taur, Ying; Sander, Chris; Cross, Justin R.; Toussaint, Nora C.; Xavier, Joao B.; Pamer, Eric G.

    2015-01-01

    The gastrointestinal tracts of mammals are colonized by hundreds of microbial species that contribute to health, including colonization resistance against intestinal pathogens. Many antibiotics destroy intestinal microbial communities and increase susceptibility to intestinal pathogens. Among these, Clostridium difficile, a major cause of antibiotic-induced diarrhoea, greatly increases morbidity and mortality in hospitalized patients. Which intestinal bacteria provide resistance to C. difficile infection and their in vivo inhibitory mechanisms remain unclear. Here we correlate loss of specific bacterial taxa with development of infection, by treating mice with different antibiotics that result in distinct microbiota changes and lead to varied susceptibility to C. difficile. Mathematical modelling augmented by analyses of the microbiota of hospitalized patients identifies resistance-associated bacteria common to mice and humans. Using these platforms, we determine that Clostridium scindens, a bile acid 7α-dehydroxylating intestinal bacterium, is associated with resistance to C. difficile infection and, upon administration, enhances resistance to infection in a secondary bile acid dependent fashion. Using a workflow involving mouse models, clinical studies, metagenomic analyses, and mathematical modelling, we identify a probiotic candidate that corrects a clinically relevant microbiome deficiency. These findings have implications for the rational design of targeted antimicrobials as well as microbiome-based diagnostics and therapeutics for individuals at risk of C. difficile infection.

  18. Photochemical decomposition of perfluorooctanoic acid mediated by iron in strongly acidic conditions

    Highlights: • Perfluorooctanoic acid (PFOA) was decomposed based on ferric ion performance. • Complete decomposition of PFOA was confirmed in strongly acidic conditions. • Fe2+ changed to Fe3+ to restore chemical equilibrium in this condition. • Fe3+ was only produced from Fe2+ by hydroxyl radical in weakly acidic conditions. • The Fe3+ regeneration mechanisms resulted in the performance of Fe3+ for PFOA. - Abstract: The performance of a ferric ion mediated photochemical process for perfluorooctanoic acid (PFOA) decomposition in strongly acidic conditions of pH 2.0 was evaluated in comparison with those in weakly acidic conditions, pH 3.7 or pH 5.0, based on iron species composition and ferric ion regeneration. Complete decomposition of PFOA under UV irradiation was confirmed at pH 2.0, whereas perfluoroheptanoic acid (PFHpA) and other intermediates were accumulated in weakly acidic conditions. Iron states at each pH were evaluated using a chemical equilibrium model, Visual MINTEQ. The main iron species at pH 2.0 is Fe3+ ion. Although Fe3+ ion is consumed and is transformed to Fe2+ ion by photochemical decomposition of PFOA and its intermediates, the produced Fe2+ ion will change to Fe3+ ion to restore chemical equilibrium. Continuous decomposition will occur at pH 2.0. However, half of the iron cannot be dissolved at pH 3.7. The main species of dissolved iron is Fe(OH)2+. At pH 3.7 or higher pH, Fe3+ ion will only be produced from the oxidation of Fe2+ ion by hydroxyl radical produced by Fe(OH)2+ under UV irradiation. These different mechanisms of Fe3+ regeneration that prevail in strongly and weakly acidic conditions will engender different performances of the ferric ion

  19. Photochemical decomposition of perfluorooctanoic acid mediated by iron in strongly acidic conditions

    Ohno, Masaki, E-mail: mohno@hiroshima-u.ac.jp [Environmental Research and Management Center, Hiroshima University, 1-5-3 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8513 (Japan); Ito, Masataka; Ohkura, Ryouichi [Faculty of Applied Life Sciences, Niigata University of Pharmacy and Applied Life Sciences, 265-1, Higashijima, Akiha-ku, Niigata 956-8603 (Japan); Mino A, Esteban R. [Environmental Research and Management Center, Hiroshima University, 1-5-3 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8513 (Japan); Kose, Tomohiro [Faculty of Applied Life Sciences, Niigata University of Pharmacy and Applied Life Sciences, 265-1, Higashijima, Akiha-ku, Niigata 956-8603 (Japan); Okuda, Tetsuji [Environmental Research and Management Center, Hiroshima University, 1-5-3 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8513 (Japan); Nakai, Satoshi [Department of Chemical Engineering, Graduate School of Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8527 (Japan); Kawata, Kuniaki [Faculty of Applied Life Sciences, Niigata University of Pharmacy and Applied Life Sciences, 265-1, Higashijima, Akiha-ku, Niigata 956-8603 (Japan); Nishijima, Wataru [Environmental Research and Management Center, Hiroshima University, 1-5-3 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8513 (Japan)

    2014-03-01

    Highlights: • Perfluorooctanoic acid (PFOA) was decomposed based on ferric ion performance. • Complete decomposition of PFOA was confirmed in strongly acidic conditions. • Fe{sup 2+} changed to Fe{sup 3+} to restore chemical equilibrium in this condition. • Fe{sup 3+} was only produced from Fe{sup 2+} by hydroxyl radical in weakly acidic conditions. • The Fe{sup 3+} regeneration mechanisms resulted in the performance of Fe{sup 3+} for PFOA. - Abstract: The performance of a ferric ion mediated photochemical process for perfluorooctanoic acid (PFOA) decomposition in strongly acidic conditions of pH 2.0 was evaluated in comparison with those in weakly acidic conditions, pH 3.7 or pH 5.0, based on iron species composition and ferric ion regeneration. Complete decomposition of PFOA under UV irradiation was confirmed at pH 2.0, whereas perfluoroheptanoic acid (PFHpA) and other intermediates were accumulated in weakly acidic conditions. Iron states at each pH were evaluated using a chemical equilibrium model, Visual MINTEQ. The main iron species at pH 2.0 is Fe{sup 3+} ion. Although Fe{sup 3+} ion is consumed and is transformed to Fe{sup 2+} ion by photochemical decomposition of PFOA and its intermediates, the produced Fe{sup 2+} ion will change to Fe{sup 3+} ion to restore chemical equilibrium. Continuous decomposition will occur at pH 2.0. However, half of the iron cannot be dissolved at pH 3.7. The main species of dissolved iron is Fe(OH){sup 2+}. At pH 3.7 or higher pH, Fe{sup 3+} ion will only be produced from the oxidation of Fe{sup 2+} ion by hydroxyl radical produced by Fe(OH){sup 2+} under UV irradiation. These different mechanisms of Fe{sup 3+} regeneration that prevail in strongly and weakly acidic conditions will engender different performances of the ferric ion.

  20. Lysophosphatidic acid mediates myeloid differentiation within the human bone marrow microenvironment.

    Denis Evseenko

    Full Text Available Lysophosphatidic acid (LPA is a pleiotropic phospholipid present in the blood and certain tissues at high concentrations; its diverse effects are mediated through differential, tissue specific expression of LPA receptors. Our goal was to determine if LPA exerts lineage-specific effects during normal human hematopoiesis. In vitro stimulation of CD34+ human hematopoietic progenitors by LPA induced myeloid differentiation but had no effect on lymphoid differentiation. LPA receptors were expressed at significantly higher levels on Common Myeloid Progenitors (CMP than either multipotent Hematopoietic Stem/Progenitor Cells (HSPC or Common Lymphoid Progenitors (CLP suggesting that LPA acts on committed myeloid progenitors. Functional studies demonstrated that LPA enhanced migration, induced cell proliferation and reduced apoptosis of isolated CMP, but had no effect on either HSPC or CLP. Analysis of adult and fetal human bone marrow sections showed that PPAP2A, (the enzyme which degrades LPA was highly expressed in the osteoblastic niche but not in the perivascular regions, whereas Autotaxin (the enzyme that synthesizes LPA was expressed in perivascular regions of the marrow. We propose that a gradient of LPA with the highest levels in peri-sinusoidal regions and lowest near the endosteal zone, regulates the localization, proliferation and differentiation of myeloid progenitors within the bone marrow marrow.

  1. Lewis-Acid-Mediated Stereospecific Radical Polymerization of Acrylimides Bearing Chiral Oxazolidinones.

    Fujita, Takehiro; Yamago, Shigeru

    2015-12-14

    Lewis acid (MgBr2)-catalyzed radical polymerization of acrylimides bearing chiral oxazolidinones gave highly isotactic polyacrylimides with up to >99% meso tetrad (mmm) selectivity. Polymerization in the absence of Lewis acid gave atactic polymers with 80% racemo diad (r) selectivity; the selectivity was deliberately tuned from 80% r to >99% mmm by varying the polymerization conditions. The polyacrylimide was quantitatively converted to corresponding polyacrylates while preserving the stereoregularity, thus providing a general method for the synthesis of atactic to isotactic polyacrylates. PMID:26500040

  2. Mechanistic Modeling Reveals the Critical Knowledge Gaps in Bile Acid-Mediated DILI.

    Woodhead, J L; Yang, K; Brouwer, K L R; Siler, S Q; Stahl, S H; Ambroso, J L; Baker, D; Watkins, P B; Howell, B A

    2014-01-01

    Bile salt export pump (BSEP) inhibition has been proposed to be an important mechanism for drug-induced liver injury (DILI). Modeling can prioritize knowledge gaps concerning bile acid (BA) homeostasis and thus help guide experimentation. A submodel of BA homeostasis in rats and humans was constructed within DILIsym, a mechanistic model of DILI. In vivo experiments in rats with glibenclamide were conducted, and data from these experiments were used to validate the model. The behavior of DILIsym was analyzed in the presence of a simulated theoretical BSEP inhibitor. BSEP inhibition in humans is predicted to increase liver concentrations of conjugated chenodeoxycholic acid (CDCA) and sulfate-conjugated lithocholic acid (LCA) while the concentration of other liver BAs remains constant or decreases. On the basis of a sensitivity analysis, the most important unknowns are the level of BSEP expression, the amount of intestinal synthesis of LCA, and the magnitude of farnesoid-X nuclear receptor (FXR)-mediated regulation. PMID:25006780

  3. Novel redox-sensing modules : Accessory protein- and nucleic acid-mediated signaling

    Siedenburg, Gabriele; Groves, Matthew R; Ortiz de Orué Lucana, Darío

    2012-01-01

    SIGNIFICANCE: Organisms have evolved both enzymatic and nonenzymatic pathways to prevent oxidative damage to essential macromolecules, including proteins and nucleic acids. Pathways modulated by different protein-based sensory and regulatory modules ensure a rapid and appropriate response. RECENT AD

  4. Bile acid mediated effects on gut integrity and performance of early-weaned piglets

    de Diego-Cabero, Nuria; Mereu, Alessandro; Menoyo, David; Holst, Jens Juul; Ipharraguerre, Ignacio R

    2015-01-01

    study on day 35. On days 1, 7 and 14 blood samples were collected from 6 pigs per treatment to measure plasma GLP-2. On day 15, 6 pigs per treatment were euthanized to obtain intestinal tissue samples for later histological and gene expression analyses. RESULTS: Supplementing the diet with CDC tended to...

  5. Ezrin dephosphorylation/downregulation contributes to ursolic acid-mediated cell death in human leukemia cells

    Ezrin links the actin filaments with the cell membrane and has a functional role in the apoptotic process. It appears clear that ezrin is directly associated with Fas, leading to activation of caspase cascade and cell death. However, the exact role of ezrin in ursolic acid (UA)-induced apoptosis remains unclear. In this study, we show for the first time that UA induces apoptosis in both transformed and primary leukemia cells through dephosphorylation/downregulation of ezrin, association and polarized colocalization of Fas and ezrin, as well as formation of death-inducing signaling complex. These events are dependent on Rho-ROCK1 signaling pathway. Knockdown of ezrin enhanced cell death mediated by UA, whereas overexpression of ezrin attenuated UA-induced apoptosis. Our in vivo study also showed that UA-mediated inhibition of tumor growth of mouse leukemia xenograft model is in association with the dephosphorylation/downregulation of ezrin. Such findings suggest that the cytoskeletal protein ezrin may represent an attractive target for UA-mediated lethality in human leukemia cells

  6. Saturated phosphatidic acids mediate saturated fatty acid–induced vascular calcification and lipotoxicity

    Masuda, Masashi; Miyazaki-Anzai, Shinobu; Audrey L Keenan; Okamura, Kayo; Kendrick, Jessica; Chonchol, Michel; Offermanns, Stefan; James M. Ntambi; Kuro-o, Makoto; Miyazaki, Makoto

    2015-01-01

    Recent evidence indicates that saturated fatty acid–induced (SFA-induced) lipotoxicity contributes to the pathogenesis of cardiovascular and metabolic diseases; however, the molecular mechanisms that underlie SFA-induced lipotoxicity remain unclear. Here, we have shown that repression of stearoyl-CoA desaturase (SCD) enzymes, which regulate the intracellular balance of SFAs and unsaturated FAs, and the subsequent accumulation of SFAs in vascular smooth muscle cells (VSMCs), are characteristic...

  7. Amino-Functional Polybenzimidazole Blends with Enhanced Phosphoric Acid Mediated Proton Conductivity as Fuel Cell Electrolytes

    Aili, David; Javakhishvili, Irakli; Han, Junyoung;

    2016-01-01

    the phosphoric acid uptake and to obtain mechanically robust membranes, the amino-functional polybenzimidazole derivative is blended with high molecular weight poly [2,2′-(m-phenylene)-5,5′-bisbenzimidazole] at different ratios. Due to the high acid uptake, the homogenous blend membranes show enhanced proton...

  8. p-Aminophenylacetic acid-mediated synthesis of monodispersed titanium oxide hybrid microspheres in ethanol solution.

    Zhang, Hongye; Xie, Yun; Liu, Zhimin; Tao, Ranting; Sun, Zhenyu; Ding, Kunlun; An, Guimin

    2009-10-15

    Monodispersed TiO2 hybrid microspheres were prepared via the hydrolysis of titanium isopropoxide (TTIP) in ethanol solution containing p-aminophenylacetic acid (APA). The effects of the APA:TTIP molar ratio, water content, reaction time and reaction temperature on the morphology of the resultant spheres were investigated. The products were characterized by scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis, and X-ray diffraction. It was demonstrated that the diameters of the resultant TiO2 spheres could be tuned in the range of 380-800 nm by changing the APA:TTIP molar ratio (1:3 to 3:1) and water content (1-3 v/v%) in the reaction medium, and that increasing the APA:TTIP molar ratio led to larger TiO2 hybrid spheres while increasing the water content decreased their size. The loading content of APA in the hybrid spheres could reach 20 wt.% as they were prepared with the APA:TTIP ratio of 3:1. The possible formation mechanism of the hybrid spheres was also investigated. It was found that APA slowed down the hydrolysis rate of the titanium precursor so that resulted in the formation of the TiO2 spheres. In addition, the APA present in TiO2 spheres acted as a reducing agent to in situ convert HAuCl4 into metallic Au on the surface of the TiO2 spheres. The catalytic activity of the resultant Au/APA-TiO2 composite was examined using transfer hydrogenation of phenylacetone with 2-propanol, and it was indicated that the catalyst displayed high efficiency for this reaction. PMID:19616218

  9. Cullin-RING Ubiquitin Ligases in Salicylic Acid-Mediated Plant Immune Signaling

    James J. Furniss

    2015-03-01

    Full Text Available Plant immune responses against biotrophic pathogens are regulated by the signaling hormone salicylic acid (SA. SA establishes immunity by regulating a variety of cellular processes, including programmed cell death (PCD to isolate and kill invading pathogens, and development of systemic acquired resistance (SAR which provides long-lasting, broad-spectrum resistance throughout the plant. Central to these processes is post-translational modification of SA-regulated signaling proteins by ubiquitination, i.e. the covalent addition of small ubiquitin proteins. Emerging evidence indicates SA-induced protein ubiquitination is largely orchestrated by Cullin-RING ligases (CRLs, which recruit specific substrates for ubiquitination using interchangeable adaptors. Ligation of ubiquitin chains interlinked at lysine 48 leads to substrate degradation by the 26S proteasome. Here we discuss how CRL-mediated degradation of both nucleotide-binding/leucine-rich repeat domain containing (NLR immune receptors and SA-induced transcription regulators are critical for functional PCD and SAR responses, respectively. By placing these recent findings in context of knowledge gained in other eukaryotic model species, we highlight potential alternative roles for processive ubiquitination in regulating the activity of SA-mediated immune responses.

  10. Lewis acid Mediated Aza-Diels-Alder Reactions and Asymmetric Alkylations of 2H-azirines

    Risberg, Erik

    2004-01-01

    This thesis describes the use of 2H-azirines, three-membered unsaturatednitrogen-containing heterocycles, as reactive intermediates ina number of Lewis acid promoted alkylations and Diels-Alderreactions providing synthetically useful aziridines. In order to carry out this investigation a new generalprocedure for the ring closure of vinyl azides, forming theresultant 3-substituted-2H-azirines, was developed applying low boiling solventsin closed reaction vessels at elevated temperatures. The a...

  11. Salicylic acid-mediated responses of Teucrium carthaginense antioxidant capacity to heavy metals

    These thousand years of mining exploitation have led to the deterioration of vast areas of the Cartagena-La Union Mining District (South-East Spain). Natural local vegetation has been seriously affected by these activities, and some plant species are considered to be critically endangered. (Author)

  12. Citric acid mediated phyto extraction of cadmium by maize (zea mays l.)

    The aim of the investigation was to determine the potential of citric acid for accumulation and translocation of cadmium and their effect on maize growth. The plants were grown in small plastic glasses and treated with 300 mg kg/sup -1/ CdCl/sub 2/ and 0, 0.25, 0.5, 1 and 2 g kg/sup -1/ of citric acid. After 10 days, the plants were harvested, dried and root and shoot biomass weighed. To study the efficiency of maize to bioaccumulate metal, uptake of cadmium was studied in the root and shoot. The results showed that heavy metal accumulated more in roots than the shoots and application of citric acid depressed Cd uptake at all concentrations. Percent decrease in Cd uptake was 58, 35, 26, 25 and 63, 46, 44, 42 by Sahiwal-2002 and Pak-affgoee, respectively at 0.25, 0.5, 1 and 2 g kg/sup -1/ of citric acid application. Maize proved to be an effective accumulator for cadmium, however, neither concentration of citric acid showed advantages for phytoextraction of cadmium. (author)

  13. Unnatural agrochemical ligands for engineered abscisic acid receptors.

    Rodriguez, Pedro L; Lozano-Juste, Jorge

    2015-06-01

    Existing agrochemicals can be endowed with new applications through protein engineering of plant receptors. A recent study shows an engineered PYR1 ABA receptor can be activated by mandipropamid. Plants engineered with such PYR1 variant are responsive to this agrochemical, which confers protection against drought through activation of ABA signaling. PMID:25891067

  14. White Matter Compromise of Callosal and Subcortical Fiber Tracts in Children with Autism Spectrum Disorder: A Diffusion Tensor Imaging Study

    Shukla, Dinesh K.; Keehn, Brandon; Lincoln, Alan J.; Muller, Ralph-Axel

    2010-01-01

    Objective: Autism spectrum disorder (ASD) is increasingly viewed as a disorder of functional networks, highlighting the importance of investigating white matter and interregional connectivity. We used diffusion tensor imaging (DTI) to examine white matter integrity for the whole brain and for corpus callosum, internal capsule, and middle…

  15. Callosal tissue loss parallels subtle decline in psychomotor speed. A longitudinal quantitative MRI study. The LADIS Study

    Jokinen, Hanna; Frederiksen, Kristian S; Garde, Ellen;

    2012-01-01

    Cross-sectional studies have suggested that corpus callosum (CC) atrophy is related to impairment in global cognitive function, mental speed, and executive functions in the elderly. Longitudinal studies confirming these findings have been lacking. We investigated whether CC tissue loss is...

  16. Spatial Coordination of Aluminum Uptake, Production of Reactive Oxygen Species, Callose Production and Wall Rigidification in Maize Roots

    Aluminum toxicity associated with acid soils represents one of the biggest limitations to crop production worldwide. Although Al specifically inhibits the elongation of root cells, the exact mechanism by which this growth reduction occurs remains controversial. The aim of this study was to investiga...

  17. Cell Wall Maturation of Arabidopsis Trichomes Is Dependent on Exocyst Subunit EXO70H4 and Involves Callose Deposition

    Kulich, I.; Vojtíková, Z.; Glanc, M.; Ortmannová, Jitka; Rasmann, S.; Žárský, Viktor

    2015-01-01

    Roč. 168, č. 1 (2015), s. 120-131. ISSN 0032-0889 Institutional support: RVO:61389030 Keywords : PLASMA-MEMBRANE * MICRO- PIXE * PLANT Subject RIV: EA - Cell Biology Impact factor: 6.841, year: 2014

  18. Visual-callosal white matter pathways in neurofibromatosis type 1: a diffusion tensor imaging-fiber tracking study

    Santos, André Miguel Fernandes dos

    2011-01-01

    O presente estudo visa investigar a providenciar informação neuro anatómica acerca do desenvolvimento das vias dorsais e ventrais de matéria branca que começam em áreas visuais corticais de baixo nível, associado à neurofibromatose tipo 1. De maneira a se atingir este objectivo, recorreu-se ao uso de técnicas de DTI (Diffusion Tensor Imaging [Imagens de Tensor de Difusão]), FT (Fiber Tracking [Tractografia]) e fMRI (Functional Magnetic Resonance Imaging [Imagens de Ressonância Magnética Funci...

  19. Callosal connections of primary visual cortex predict the spatial spreading of binocular rivalry across the visual hemifields

    Erhan eGenc

    2011-12-01

    Full Text Available In binocular rivalry, presentation of different images to the separate eyes leads to conscious perception alternating between the two possible interpretations every few seconds. During perceptual transitions, a stimulus emerging into dominance can spread in a wave-like manner across the visual field. These traveling waves of rivalry dominance have been successfully related to the cortical magnification properties and functional activity of early visual areas, including the primary visual cortex (V1. Curiously however, these traveling waves undergo a delay when passing from one hemifield to another. In the current study, we used diffusion tensor imaging (DTI to investigate whether the strength of interhemispheric connections between the left and right visual cortex might be related to the delay of traveling waves across hemifields. We measured the delay in traveling-wave times (ΔTWT in nineteen participants and repeated this test 6 weeks later to evaluate the reliability of our behavioral measures. We found large interindividual variability but also good test-retest reliability for individual measures of ΔTWT. Using DTI in connection with fiber tractography, we identified parts of the corpus callosum connecting functionally defined visual areas V1-V3. We found that individual differences in ΔTWT was reliably predicted by the diffusion properties of transcallosal fibers connecting left and right V1, but observed no such effect for neighboring transcallosal visual fibers connecting V2 and V3. Our results demonstrate that the anatomical characteristics of topographically specific transcallosal connections predict the individual delay of interhemispheric traveling waves, providing further evidence that V1 is an important site for neural processes underlying binocular rivalry.

  20. Aminolevulinic Acid-Mediated Photodynamic Therapy of Human Meningioma: An in Vitro Study on Primary Cell Lines

    Mustafa El-Khatib

    2015-04-01

    Full Text Available Objective: Five-aminolevulinic acid (5-ALA-induced porphyrins in malignant gliomas are potent photosensitizers. Promising results of ALA-PDT (photodynamic therapy in recurrent glioblastomas have been published. Recently, 5-ALA-induced fluorescence was studied in meningioma surgery. Here, we present an experimental study of ALA-PDT in an in vitro model of primary meningioma cell lines. Methods: We processed native tumor material obtained intra-operatively within 24 h for cell culture. Epithelial membrane antigen (EMA immunohistochemistry was performed after the first passage to confirm that cells were meningioma cells. For 5-ALA-PDT treatment, about 5000 cells per well were seeded in 20 wells of a blank 96-well plate. Each block of 4 wells was inoculated with 150 µL of 0, 25, 50 and 100 µg/mL 5-ALA solutions; one block was used as negative control without 5-ALA and without PDT. Following incubation for 3 h PDT was performed using a laser (635 nm, 18.75 J/cm2. The therapeutic response was analyzed by the water soluble tetrazolium salt (WST-1 cell viability assay 90 min after PDT. Results: 5-ALA-PDT was performed in 14 primary meningioma cell lines. EMA expression was verified in 10 primary cell cultures. The remaining 4 were EMA negative and PDT was without any effect in these cultures. All 10 EMA-positive cell lines showed a significant and dose-dependent decrease in viability rate (p < 0.001. Cell survival at 5-ALA concentrations of 12.5, 25, 50 and 100 μg/mL was 96.5% ± 7.6%, 67.9% ± 29.9%, 24.0% ± 16.7% and 13.8% ± 7.5%, respectively. For the negative controls (no 5-ALA/PDT and ALA/no PDT, the viability rates were 101.72% ± 3.5% and 100.17% ± 3.6%, respectively. The LD50 for 5-ALA was estimated between 25 and 50 µg/mL. Conclusion: This study reveals dose-dependent cytotoxic effects of 5-ALA-PDT on primary cell lines of meningiomas. Either 5-ALA or PDT alone did not affect cell survival. Further efforts are necessary to study the potential therapeutic effects of 5-ALA-PDT in vivo.

  1. A family of conserved bacterial effectors inhibits salicylic acid-mediated basal immunity and promotes disease necrosis in plants

    DebRoy, Sruti; Thilmony, Roger; Kwack, Yong-Bum; Nomura, Kinya; He, Sheng Yang

    2004-01-01

    Salicylic acid (SA)-mediated host immunity plays a central role in combating microbial pathogens in plants. Inactivation of SA-mediated immunity, therefore, would be a critical step in the evolution of a successful plant pathogen. It is known that mutations in conserved effector loci (CEL) in the plant pathogens Pseudomonas syringae (the ΔCEL mutation), Erwinia amylovora (the dspA/E mutation), and Pantoea stewartii subsp. stewartii (the wtsE mutation) exert particularly strong negative effect...

  2. Isomerization of all-(E)-Retinoic Acid Mediated by Carbodiimide Activation - Synthesis of ATRA Ether Lipid Conjugates

    Christensen, Mikkel Stochkendahl; Pedersen, Palle Jacob; Andresen, Thomas Lars;

    2010-01-01

    Treatment of the lysolipid 1-O-hexadecyl-sn-phosphatidylcholine with all-(E)-retinoic acid, DCC and DMAP resulted in poor acylation and caused (Z)/(E) isomerization of the alpha-beta double bond. In the presence of a proton source, the carbodiimide-activated all-(E)-retinoic acid undergoes fast...... isomerization to give a final mixture of (13E)/(13Z) isomers in a 3:1 ratio. Similar treatment of (13Z)-retinoic acid leads to the same isomer ratio. The isomerization was circumvented successfully by using a Mitsunobu reaction, which provided an efficient synthesis of all-(E)-retinoic acid sn-2-conjugated to...

  3. A potential plant-derived antifungal acetylenic acid mediates its activity by interfering with fatty acid homeostasis

    6-Nonadecynoic acid (6-NDA), a plant-derived acetylenic acid, exhibits strong inhibitory activity against the human fungal pathogens Candida albicans, Aspergillus fumigatus, and Trichophyton mentagrophytes. In the present study, transcriptional profiling coupled with mutant and biochemical analyses...

  4. Conjugated Linoleic Acids Mediate Insulin Release through Islet G Protein-coupled Receptor FFA1/GPR40

    Schmidt, Johannes; Liebscher, Kathrin; Merten, Nicole;

    2011-01-01

    of insulin resistance and the risk of developing diabetes. However, the mechanisms accounting for the effects of CLAs on glucose homeostasis are incompletely understood. Herein we provide evidence that CLAs specifically activate the cell surface receptor FFA1, an emerging therapeutic target to treat...... type 2 diabetes. Using different recombinant cellular systems engineered to stably express FFA1 and a set of diverse functional assays including the novel, label-free non-invasive dynamic mass redistribution technology (Corning® Epic® biosensor), both CLA isomers cis-9, trans-11-CLA and trans-10, cis......-12-CLA were found to activate FFA1 in vitro at concentrations sufficient to also account for FFA1 activation in vivo. Each CLA isomer markedly increased glucose-stimulated insulin secretion in insulin-producing INS-1E cells that endogenously express FFA1 and in primary pancreatic β-cells of wild type...

  5. Phenolic Acid-Mediated Regulation of the padC Gene, Encoding the Phenolic Acid Decarboxylase of Bacillus subtilis▿ †

    Tran, Ngoc Phuong; Gury, Jerôme; Dartois, Véronique; Nguyen, Thi Kim Chi; Seraut, Hélène; Barthelmebs, Lise; Gervais, Patrick; Cavin, Jean-François

    2008-01-01

    In Bacillus subtilis, several phenolic acids specifically induce expression of padC, encoding a phenolic acid decarboxylase that converts these antimicrobial compounds into vinyl derivatives. padC forms an operon with a putative coding sequence of unknown function, yveFG, and this coding sequence does not appear to be involved in the phenolic acid stress response (PASR). To identify putative regulators involved in the PASR, random transposon mutagenesis, combined with two different screens, w...

  6. Phenazine-1-carboxylic acid mediated anti-oomycete activity of the endophytic Alcaligenes sp. EIL-2 against Phytophthora meadii.

    Abraham, Amith; Philip, Shaji; Jacob, Manoj Kurian; Narayanan, Sunilkumar Puthenpurackel; Jacob, C Kuruvilla; Kochupurackal, Jayachandran

    2015-01-01

    The oomycete pathogen, Phytophthora meadii, causes various diseases in Hevea brasiliensis at different stages of its life cycle. The study reports the structural characterization of the active principle from the culture filtrate of Alcaligenes sp. EIL-2 (GenBank ID: HQ641257) offering antagonistic activity against P. meadii. Gas Chromatography Mass Spectroscopy (GC-MS) analysis showed the similarity of the compound with phenazine derivatives. The specific representations of FT-IR spectrum such as 3200 cm(-1) (OH stretching, NH stretching and presence of aromatic ring), 1737 cm(-1) (carboxylic acid), 2200-2400 cm(-1) (conjugated dienes) and 1467 cm(-1), and 1422 cm(-1) (CN bonds) were an indicative of phenazine-1-carboxylic acid (PCA). The structure of the compound was further confirmed by (1)H NMR/(13)C NMR spectroscopy, DEPT experiments, and two-dimensional NMR spectral studies, including (1)H-(1)H COSY and (1)H-(13)C HSQC as PCA with the molecular formula of C₁₃H₈N₂O₂. P. meadii was sensitive to purified PCA extract from the endophyte and a concentration of 5 μg/ml completely inhibited the mycelia growth. PCA also showed zoosporicidal activity against P. meadii zoospores. This is the first study of this kind where PCA from an endophyte of H. brasiliensis is being confirmed to carry antagonistic activity against P. meadii. PMID:24985092

  7. Lactic acid-mediated tandem one-pot synthesis of 2-aminothiazole derivatives: A rapid, scalable, and sustainable process

    Mohan Reddy Bodireddy

    2016-12-01

    Full Text Available Environmentally benign and biodegradable lactic acid is identified as alternative solvent and catalyst for the tandem one-pot synthesis of Hantzsch 2-aminothiazole derivatives (4 from readily available aralkyl ketones (1 through in situ regioselective α-bromination using N-bromosuccinimide (2 followed by heterocyclization using thiourea (3 at 90–100°C. The major advantages of the present method include short reaction times (10–15 min, practical, simple to perform, easy work-up, good yield of products (up to 96%, productive for large-scale applications, free from apply of α-bromoketones (lachrymator as substrates, avoids column purification. Hence, the present method meets with the concepts of both Wender’s “ideal synthesis” and sustainable chemical process.

  8. Stereoselective Formation of Trisubstituted Vinyl Boronate Esters by the Acid-Mediated Elimination of α-Hydroxyboronate Esters

    Guan, Weiye; Michael, Alicia K.; McIntosh, Melissa L.; Koren-Selfridge, Liza; Scott, John P.; Clark, Timothy B.

    2014-01-01

    The copper-catalyzed diboration of ketones followed by an acid-catalyzed elimination leads to the formation of 1,1-disubstituted and trisubstituted vinyl boronate esters with moderate to good yields and selectivity. Addition of tosic acid to the crude diboration products provides the corresponding vinyl boronate esters upon elimination. The trisubstituted vinyl boronate esters are formed as the (Z)-olefin isomer, which was established by subjecting the products to a Suzuki–Miyaura coupling re...

  9. Synergistic Cytotoxic Effect of Gold Nanoparticles and 5-Aminolevulinic Acid-Mediated Photodynamic Therapy against Skin Cancer Cells

    Mahnaz Hadizadeh

    2014-09-01

    Full Text Available Background: Photodynamic therapy (PDT is a promising therapeutic modality for the treatment of cancer and other diseases. In this study, the epidermoid carcinoma cell line A431 and the normal fibroblasts were used to investigate whether gold nanoparticles (GNPs can induce an increase in cell death during PDT using 5-aminolevulinic acid (5-ALA as a photosensitizer. Methods: Human fibroblast and A431 cells were grown in 96-well plates. The effect of GNPs on the efficacy of 5-ALA-mediated PDT (5-ALA-PDT was evaluated by comparing the effect of 5-ALA with GNPs to the effect of 5-ALA alone. Cell viability was determined by the methyl- tetrazolium assay. Results: Dark toxicity experiments showed that 5-ALA at concentrations 0.5, 1 and 2 mM had no significant effect on cell viability of both cell lines. However, treatment of cells with 5-ALA (0.5 to 2 mM and light dose of 25 Jcm-2 led to 5-10% and 31-42% decrease in cell viability of fibroblast and A431 cells respectively. The data also shows that GNPs in both the absence and the presence of light, results in a dose-dependent decrease in cell viability of both cell lines. However, the sensitivity of cancer cells to GNPs at concentrations more than 24 μg/ml was approximately 2.5- to 4-fold greater than healthy cells. Furthermore, data indicates that 5-ALA in combination with GNPs results in a synergistic reduction in viability of A431 cells. Conclusion: In summary, the findings of this study suggest that concomitant treatment with 5-ALA and GNPs may be useful in enhancing the effect of 5-ALA-PDT.

  10. Suppression of Salicylic Acid-Mediated Plant Defense Responses During Initial Infection of Dyer's Woad by Puccinia thlaspeos

    Elizabeth Thomas

    2011-01-01

    Full Text Available Problem statement: Puccinia thlaspeos is a microcyclic rust pathogen that is being investigated as a potential biocontrol agent of the noxious weed, dyer’s woad (Isatis tinctoria. Although, the initial events in the colonization of dyer’s woad by the rust pathogen has been elucidated using scanning electron microscopy and PCR, little is known regarding the susceptibility response of this plant to its rust pathogen. Approach: The induction kinetics and amplitude of the Salicylic Acid (SA-responsive Pathogenesis-Related (PR genes, PR-1, â-1, 3-glucanase and ChiA in the compatible interaction between the rust pathogen Puccinia thlaspeos and dyer’s woad were examined during the first 72 h of the infection process. Furthermore SA, an inducer of plant defense response was applied to infected plants in order to reprogram the host defense response at periods that coincided with key events of the infection process. Results: PR genes were upregulated following host penetration by the pathogen. A subsequent pathogen-mediated suppression of PR genes was seen that corresponded with haustorium formation. This was followed by a second up-regulation of these genes that was, in turn, followed by a second long-term pathogen-induced suppression of the defense response that appears to allow successful infections in dyer’s woad. Exogenous application of SA to uninoculated plants led to activation of defense responses by 8 h after treatment. In treatments where inoculated plants were treated with SA, responses differed depending on the timing of SA application. Application of SA at times corresponding to the pre-haustorial and posthaustorial phases of infection triggered an up-regulation of defense genes and increased protection against the pathogen. However, the application of SA during haustorium formation could not override the pathogen-mediated suppression of defense responses and consequently, did not offer the host increased protection. Conclusion: Although pathogen-induced PR expression was observed during rust infection of dyer’s woad, it appears to be insufficient to inhibit fungal growth during the compatible interaction between dyer’s woad and the rust pathogen. Suppression of pathogeninduced host defense responses during and after haustorium formation is postulated to be vital in the establishment of biotrophy in this system.

  11. Suppression of Jasmonic Acid-Mediated Defense by Viral-Inducible MicroRNA319 Facilitates Virus Infection in Rice.

    Zhang, Chao; Ding, Zuomei; Wu, Kangcheng; Yang, Liang; Li, Yang; Yang, Zhen; Shi, Shan; Liu, Xiaojuan; Zhao, Shanshan; Yang, Zhirui; Wang, Yu; Zheng, Luping; Wei, Juan; Du, Zhenguo; Zhang, Aihong; Miao, Hongqin; Li, Yi; Wu, Zujian; Wu, Jianguo

    2016-09-01

    MicroRNAs (miRNAs) are pivotal modulators of plant development and host-virus interactions. However, the roles and action modes of specific miRNAs involved in viral infection and host susceptibility remain largely unclear. In this study, we show that Rice ragged stunt virus (RRSV) infection caused increased accumulation of miR319 but decreased expression of miR319-regulated TCP (TEOSINTE BRANCHED/CYCLOIDEA/PCF) genes, especially TCP21, in rice plants. Transgenic rice plants overexpressing miR319 or downregulating TCP21 exhibited disease-like phenotypes and showed significantly higher susceptibility to RRSV in comparison with the wild-type plants. In contrast, only mild disease symptoms were observed in RRSV-infected lines overexpressing TCP21 and especially in the transgenic plants overexpressing miR319-resistant TCP21. Both RRSV infection and overexpression of miR319 caused the decreased endogenous jasmonic acid (JA) levels along with downregulated expression of JA biosynthesis and signaling-related genes in rice. However, treatment of rice plants with methyl jasmonate alleviated disease symptoms caused by RRSV and reduced virus accumulation. Taken together, our results suggest that the induction of miR319 by RRSV infection in rice suppresses JA-mediated defense to facilitate virus infection and symptom development. PMID:27381440

  12. Release of UV-absorbing substances from maize coleoptiles during auxin-, fusicoccin- and acid-mediated elongation growth

    Isolated cell walls from maize coleoptiles prepared under conditions that preserve the ability for enzymatic hemicellulose autolysis release UV-absorbing substances into the incubation medium in a time-dependent reaction with an optimal rate at pH 6–7. The reaction can be inhibited by low temperature and protein-denaturing treatments, indicating an enzymatic process. Spectroscopic and chromatographic analyses showed that the liberated substances represent a complex mixture of free and bound (alkali-hydrolyzable) phenolic compounds with similar absorption spectra restricted to the range below 300 nm and thus excluding hydroxycinnamic acids from cell-wall esters. A spectroscopically and chromatographically similar mixture of soluble UV-absorbing substances is released if living (abraded) maize coleoptiles or coleoptile segments are incubated in water or buffer, suggesting that insoluble phenolic materials in the cell wall are metabolized also in vivo. This reaction can be promoted by anaerobic conditions and application of fusicoccin whereas auxin had a slightly inhibitory effect. No clear relationship to elongation growth could be demonstrated. We conclude from these results that polymeric phenolic constituents of the cell wall are subject to enzymatic degradation in muro similar to polysaccharide autolysis and that this process is under metabolic control

  13. Arachidonic acid mediates muscarinic inhibition and enhancement of N-type Ca2+ current in sympathetic neurons

    Liu, Liwang; Rittenhouse, Ann R.

    2002-01-01

    N-type Ca2+ channels participate in acute activity-dependent processes such as regulation of Ca2+-activated K+ channels and in more prolonged events such as gene transcription and long-term depression. A slow postsynaptic M1 muscarinic receptor-mediated modulation of N-type current in superior cervical ganglion neurons may be important in regulating these processes. This slow pathway inhibits N-type current by using a diffusible second messenger that has remained unidentified for more than a ...

  14. Mixed phenolic acids mediated proliferation of pathogens Talaromyces helicus and Kosakonia sacchari in continuously monocultured Radix pseudostellariae rhizosphere soil

    Hongmiao eWu

    2016-03-01

    Full Text Available Radix pseudostellariae L. is a common and popular Chinese medication. However, continuous monoculture has increased its susceptibility to severe diseases. We identified two pathogenic microorganisms, Talaromyces helicus M. (KU355274 and Kosakonia sacchari W. (KU324465, and their antagonistic bacterium, Bacillus pumilus Z. in rhizosphere soil of continuously monocultured R. pseudostellariae. Nine types of phenolic acids were identified both in the rhizosphere soil and in culture medium under sterile conditions. A syringic acid and phenolic acid mixture significantly promoted the growth of T. helicus and K. sacchari. T. helicus could utilize eight types of phenolic acids, whereas K. sacchari could only use four phenolic acids. K. sacchari produced protocatechuic acid when consuming vanillin. Protocatechuic acid negatively affected the growth of B. pumilus. The 3A-DON toxin produced by T. helicus promoted the growth of K. sacchari and inhibited growth of B. pumilus at low concentrations. These data help explain why phenolic exudates mediate a microflora shift and structure disorder in the rhizosphere soil of continuously monocultured R. pseudostellariae and lead to increased replanting disease incidence.

  15. Mixed Phenolic Acids Mediated Proliferation of Pathogens Talaromyces helicus and Kosakonia sacchari in Continuously Monocultured Radix pseudostellariae Rhizosphere Soil.

    Wu, Hongmiao; Wu, Linkun; Wang, Juanying; Zhu, Quan; Lin, Sheng; Xu, Jiahui; Zheng, Cailiang; Chen, Jun; Qin, Xianjin; Fang, Changxun; Zhang, Zhixing; Azeem, Saadia; Lin, Wenxiong

    2016-01-01

    Radix pseudostellariae L. is a common and popular Chinese medication. However, continuous monoculture has increased its susceptibility to severe diseases. We identified two pathogenic microorganisms, Talaromyces helicus M. (KU355274) and Kosakonia sacchari W. (KU324465), and their antagonistic bacterium, Bacillus pumilus Z. in rhizosphere soil of continuously monocultured R. pseudostellariae. Nine types of phenolic acids were identified both in the rhizosphere soil and in culture medium under sterile conditions. A syringic acid and phenolic acid mixture significantly promoted the growth of T. helicus and K. sacchari. T. helicus could utilize eight types of phenolic acids, whereas K. sacchari could only use four phenolic acids. K. sacchari produced protocatechuic acid when consuming vanillin. Protocatechuic acid negatively affected the growth of B. pumilus. The 3A-DON toxin produced by T. helicus promoted the growth of K. sacchari and inhibited growth of B. pumilus at low concentrations. These data help explain why phenolic exudates mediate a microflora shift and structure disorder in the rhizosphere soil of continuously monocultured R. pseudostellariae and lead to increased replanting disease incidence. PMID:27014250

  16. Deoxycholic acid mediates non-canonical EGFR-MAPK activation through the induction of calcium signaling in colon cancer cells.

    Centuori, Sara M; Gomes, Cecil J; Trujillo, Jesse; Borg, Jamie; Brownlee, Joshua; Putnam, Charles W; Martinez, Jesse D

    2016-07-01

    Obesity and a western diet have been linked to high levels of bile acids and the development of colon cancer. Specifically, increased levels of the bile acid deoxycholic acid (DCA), an established tumor promoter, has been shown to correlate with increased development of colorectal adenomas and progression to carcinoma. Herein we investigate the mechanism by which DCA leads to EGFR-MAPK activation, a candidate mechanism by which DCA may promote colorectal tumorigenesis. DCA treated colon cancer cells exhibited strong and prolonged activation of ERK1/2 when compared to EGF treatment alone. We also showed that DCA treatment prevents EGFR degradation as opposed to the canonical EGFR recycling observed with EGF treatment. Moreover, the combination of DCA and EGF treatment displayed synergistic activity, suggesting DCA activates MAPK signaling in a non-canonical manner. Further evaluation showed that DCA treatment increased intracellular calcium levels and CAMKII phosphorylation, and that blocking calcium with BAPTA-AM abrogated MAPK activation induced by DCA, but not by EGF. Finally we showed that DCA-induced CAMKII leads to MAPK activation through the recruitment of c-Src. Taken together, we demonstrated that DCA regulates MAPK activation through calcium signaling, an alternative mechanism not previously recognized in human colon cancer cells. Importantly, this mechanism allows for EGFR to escape degradation and thus achieve a constitutively active state, which may explain its tumor promoting effects. PMID:27086143

  17. Alpha-lipoic acid-mediated activation of muscarinic receptors improves hippocampus- and amygdala-dependent memory.

    Mahboob, Aamra; Farhat, Syeda Mehpara; Iqbal, Ghazala; Babar, Mustafeez Mujtaba; Zaidi, Najam-us-Sahar Sadaf; Nabavi, Seyed Mohammad; Ahmed, Touqeer

    2016-04-01

    Aluminum (Al) is a neurotoxic agent which readily crosses the blood-brain-barrier (BBB) and accumulates in the brain leading to neurodegenerative disorders, characterised by cognitive impairment. Alpha-lipoic acid (ALA) is an antioxidant and has a potential to improve cognitive functions. This study aimed to evaluate the neuroprotective effect of ALA in AlCl3-induced neurotoxicity mouse model. Effect of ALA (25mg/kg/day) was evaluated in the AlCl3-induced neurotoxicity (AlCl3 150 mg/kg/day) mouse model on learning and memory using behaviour tests and on the expression of muscarinic receptor genes (using RT-PCR), in hippocampus and amygdala. Following ALA treatment, the expression of muscarinic receptor genes M1, M2 and choline acetyltransferase (ChaT) were significantly improved (penhanced fear memory (pmemory was remarkably restored (penhancement thus presenting it an enviable therapeutic candidate for the treatment of neurodegenerative disorders. PMID:26912408

  18. Polysaccharide Capsule and Sialic Acid-Mediated Regulation Promote Biofilm-Like Intracellular Bacterial Communities during Cystitis ▿

    Anderson, Gregory G.; Goller, Carlos C.; Justice, Sheryl; Hultgren, Scott J.; Seed, Patrick C.

    2010-01-01

    Uropathogenic Escherichia coli (UPEC) is the leading cause of urinary tract infections (UTIs). A murine UTI model has revealed an infection cascade whereby UPEC undergoes cycles of invasion of the bladder epithelium, intracellular proliferation in polysaccharide-containing biofilm-like masses called intracellular bacterial communities (IBC), and then dispersal into the bladder lumen to initiate further rounds of epithelial colonization and invasion. We predicted that the UPEC K1 polysaccharid...

  19. Physical size of the donor locus and transmission of Haemophilus influenzae ampicillin resistance genes by deoxyribonucleic acid-mediated transformation

    The properties of donor deoxyribonucleic acid (DNA) from three clinical isolates and its ability to mediate the transformation of competent Rd strains to ampicillin resistance were examined. A quantitative technique for determining the resistance of individual Haemophilus influenzae cells to ampicillin was developed. When this technique was used, sensitive cells failed to tolerate levels of ampicillin greater than 0.1 to 0.2 μg/ml, whereas three resistant type b β-lactamase-producing strains could form colonies 1- to 3-μg/ml levels of the antibiotic. DNA extracted from the resistant strains elicited transformation of the auxotrophic genes in a multiply auxotrophic Rd strain. For two of the donors, transformation to ampicillin resistance occurred after the uptake of a single DNA molecule approximately 104-fold less frequently than transformation of auxotrophic loci and was not observed to occur at all with the third. The frequency of transformation to ampicillin resistance was two- to fivefold higher in strain BC200 (Okinaka and Barnhart, 1974), which was cured of a defective prophage. All three clinical ampicillin-resistant strains were poor recipients, but the presence of the ampicillin resistant genes in strain BC200 did not reduce its competence

  20. Bile acids-mediated overexpression of MUC4 via FAK-dependent c-Jun activation in pancreatic cancer.

    Joshi, Suhasini; Cruz, Eric; Rachagani, Satyanarayana; Guha, Sushovan; Brand, Randall E; Ponnusamy, Moorthy P; Kumar, Sushil; Batra, Surinder K

    2016-08-01

    The majority of pancreatic cancer (PC) patients are clinically presented with obstructive jaundice with elevated levels of circulatory bilirubin and alkaline phosphatases. In the current study, we examined the implications of bile acids (BA), an important component of bile, on the pathophysiology of PC and investigated their mechanistic association in tumor-promoting functions. Integration of results from PC patient samples and autochthonous mouse models showed an elevated levels of BA (p < 0.05) in serum samples compared to healthy controls. Similarly, an elevated BA levels was observed in pancreatic juice derived from PC patients (p < 0.05) than non-pancreatic non-healthy (NPNH) controls, further establishing the clinical association of BA with the pathogenesis of PC. The tumor-promoting functions of BA were established by observed transcriptional upregulation of oncogenic MUC4 expression. Luciferase reporter assay revealed distal MUC4 promoter as the primary responsive site to BA. In silico analysis recognized two c-Jun binding sites at MUC4 distal promoter, which was biochemically established using ChIP assay. Interestingly, BA treatment led to an increased transcription and activation of c-Jun in a FAK-dependent manner. Additionally, BA receptor, namely FXR, which is also upregulated at transcriptional level in PC patient samples, was demonstrated as an upstream molecule in BA-mediated FAK activation, plausibly by regulating Src activation. Altogether, these results demonstrate that elevated levels of BA increase the tumorigenic potential of PC cells by inducing FXR/FAK/c-Jun axis to upregulate MUC4 expression, which is overexpressed in pancreatic tumors and is known to be associated with progression and metastasis of PC. PMID:27185392

  1. Amino acid mediated synthesis of silver nanoparticles and preparation of antimicrobial agar/silver nanoparticles composite films.

    Shankar, Shiv; Rhim, Jong-Whan

    2015-10-01

    Silver nanoparticles (AgNPs) were synthesized using amino acids (tyrosine and tryptophan) as reducing and capping agents, and they were incorporated into the agar to prepare antimicrobial composite films. The AgNPs solutions exhibited characteristic absorption peak at 420 nm that showed a red shift to ∼434 nm after forming composite with agar. XRD data demonstrated the crystalline structure of AgNPs with dominant (111) facet. Apparent surface color and transmittance of agar films were greatly influenced by the AgNPs. The incorporation of AgNPs into agar did not exhibit any change in chemical structure, thermal stability, moisture content, and water vapor permeability. The water contact angle, tensile strength, and modulus decreased slightly, but elongation at break increased after AgNPs incorporation. The agar/AgNPs nanocomposite films possessed strong antibacterial activity against Listeria monocytogenes and Escherichia coli. The agar/AgNPs film could be applied to the active food packaging by controlling the food-borne pathogens. PMID:26076636

  2. Lipids in salicylic acid-mediated defense in plants: focusing on the roles of phosphatidic acid and phosphatidylinositol 4-phosphate

    Qiong eZhang

    2015-05-01

    Full Text Available Plants have evolved effective defense strategies to protect themselves from various pathogens. Salicylic acid (SA is an essential signaling molecule that mediates pathogen-triggered signals perceived by different immune receptors to induce downstream defense responses. While many proteins play essential roles in regulating SA signaling, increasing evidence also supports important roles for signaling phospholipids in this process. In this review, we collate the experimental evidence in support of the regulatory roles of two phospholipids, phosphatidic acid (PA and phosphatidylinositol 4-phosphate (PI4P, and their metabolizing enzymes in plant defense, and examine the possible mechanistic interaction between phospholipid signaling and SA-dependent immunity with a particular focus on the immunity-stimulated biphasic PA production that is reminiscent of and perhaps mechanistically connected to the biphasic reactive oxygen species (ROS generation and SA accumulation during defense activation.

  3. Stromal COX-2 signaling activated by deoxycholic acid mediates proliferation and invasiveness of colorectal epithelial cancer cells

    Highlights: ► Human colonic cancer associated fibroblasts are major sources of COX-2 and PGE2. ► The fibroblasts interact with human colonic epithelial cancer cells. ► Activation of COX-2 signaling in the fibroblasts affects behavior of the epithelia. ► Protein Kinase C controls the activation of COX-2 signaling. -- Abstract: COX-2 is a major regulator implicated in colonic cancer. However, how COX-2 signaling affects colonic carcinogenesis at cellular level is not clear. In this article, we investigated whether activation of COX-2 signaling by deoxycholic acid (DCA) in primary human normal and cancer associated fibroblasts play a significant role in regulation of proliferation and invasiveness of colonic epithelial cancer cells. Our results demonstrated while COX-2 signaling can be activated by DCA in both normal and cancer associated fibroblasts, the level of activation of COX-2 signaling is significantly greater in cancer associated fibroblasts than that in normal fibroblasts. In addition, we discovered that the proliferative and invasive potential of colonic epithelial cancer cells were much greater when the cells were co-cultured with cancer associated fibroblasts pre-treated with DCA than with normal fibroblasts pre-treated with DCA. Moreover, COX-2 siRNA attenuated the proliferative and invasive effect of both normal and cancer associate fibroblasts pre-treated with DCA on the colonic cancer cells. Further studies indicated that the activation of COX-2 signaling by DCA is through protein kinase C signaling. We speculate that activation of COX-2 signaling especially in cancer associated fibroblasts promotes progression of colonic cancer.

  4. Stereoselective formation of trisubstituted vinyl boronate esters by the acid-mediated elimination of α-hydroxyboronate esters.

    Guan, Weiye; Michael, Alicia K; McIntosh, Melissa L; Koren-Selfridge, Liza; Scott, John P; Clark, Timothy B

    2014-08-01

    The copper-catalyzed diboration of ketones followed by an acid-catalyzed elimination leads to the formation of 1,1-disubstituted and trisubstituted vinyl boronate esters with moderate to good yields and selectivity. Addition of tosic acid to the crude diboration products provides the corresponding vinyl boronate esters upon elimination. The trisubstituted vinyl boronate esters are formed as the (Z)-olefin isomer, which was established by subjecting the products to a Suzuki-Miyaura coupling reaction to obtain alkenes of known geometry. PMID:24915498

  5. Enhancement of the citrus immune system provides effective resistance against Alternaria brown spot disease.

    Llorens, Eugenio; Fernández-Crespo, Emma; Vicedo, Begonya; Lapeña, Leonor; García-Agustín, Pilar

    2013-01-15

    In addition to basal defense mechanisms, plants are able to develop enhanced defense mechanisms such as induced resistance (IR) upon appropriate stimulation. We recently described the means by which several carboxylic acids protect Arabidopsis and tomato plants against fungi. In this work, we demonstrate the effectiveness of hexanoic acid (Hx) in the control of Alternaria brown spot (ABS) disease via enhancement of the immune system of Fortune mandarin. The application of 1mM Hx in irrigation water to 2-year-old Fortune plants clearly reduced the incidence of the disease and led to smaller lesions. We observed that several of the most important mechanisms involved in induced resistance were affected by Hx application. Our results demonstrate enhanced callose deposition in infected plants treated with Hx, which suggests an Hx priming mechanism. Plants treated with the callose inhibitor 2-DDG were more susceptible to the fungus. Moreover, polygalacturonase-inhibiting protein (PGIP) gene expression was rapidly and significantly upregulated in treated plants. However, treatment with Hx decreased the levels of reactive oxygen species (ROS) in infected plants. Hormonal and gene analyses revealed that the jasmonic acid (JA) pathway was activated due to a greater accumulation of 12-oxo-phytodienoic acid (OPDA) and JA along with a rapid accumulation of JA-isoleucine (JA-Ile). Furthermore, we observed a more rapid accumulation of abscisic acid (ABA), which could act as a positive regulator of callose deposition. Thus, our results support the hypothesis that both enhanced physical barriers and the JA signaling pathway are involved in hexanoic acid-induced resistance (Hx-IR) to Alternaria alternata. PMID:23260526

  6. Analysis of Cytokinin Mutants and Regulation of Cytokinin Metabolic Genes Reveals Important Regulatory Roles of Cytokinins in Drought, Salt and Abscisic Acid Responses, and Abscisic Acid Biosynthesis

    Nishiyama, R.; Watanabe, Y.; Werner, T.; Vaňková, Radomíra; Schmülling, T.; Tran, L. S. P.

    2011-01-01

    Roč. 23, č. 6 (2011), s. 2169-2183. ISSN 1040-4651 Institutional research plan: CEZ:AV0Z50380511 Keywords : TRANSGENIC TOBACCO PLANTS * WATER-STRESS * LEAF SENESCENCE Subject RIV: ED - Physiology Impact factor: 8.987, year: 2011

  7. COPPER AMINE OXIDASE1 (CuA01)of Arabidopsis thaliana Contributes to Abscisic Acid-and Polyamine-Induced Nitric Oxide Biosynthesis and Abscisic Acid Signal Transduction

    Rinukshi Wimalasekera; Corina Villar; Tahmina Begum; Günther F. E. Scherer

    2011-01-01

    Polyamines (PA), polyamine oxidases, copper amine oxidases, and nitric oxide (NO)play important roles in physiology and stress responses in plants. NO biosynthesis as a result of catabolism of PA by polyamine oxidases and copper amine oxidases may explain in part PA-mediated responses. Involvement of a copper amine oxidase gene, COPPER AMINE OXIDASE1 (CuA01), of Arabidopsis was tested for its role in stress responses using the knockouts cuaol.1 and cuaol-2. PA-induced and ABA-induced NO production investigated by fluorometry and fluorescence microscopy showed that the cuaol-1 and cuaol-2 are impaired in NO production, suggesting a function of CuAO1 in PA and ABA-mediated NO production. Furthermore, we found a PA-dependent increase in protein S-nitrosylation. The addition of PA and ABA also resulted in HO increases, cuaol-1 and cuaol-2 showed less sensitivity to exogenous ABA supplementation during ger-mination, seedling establishment, and root growth inhibition as compared to wild-type. In response to ABA treatment,expression levels of the stress-responsive genes RD29A and ADH1 were significantly lower in the knockouts. These obser-vations characterize cuaol-1 and cuaol-2 as ABA-insensitive mutants. Taken together, our findings extend the ABA signal transduction network to include CuAO1 as one potential contributor to enhanced NO production by ABA.

  8. Transcription of storage protein genes in cultured Brassica napus embryos in response to exogenous abscisic acid

    Two major seed storage proteins, cruciferin and napin, accumulate during embryogeny in Brassica napus. We are determining whether the levels of storage protein mRNAs in cultured embryos are controlled at the transcriptional level in response to ABA. The nuclei were isolated from the embryos and incubated in a transcription mix with 32P-GTP, and the incorporation into specific RNAs was determined by DNA excess filter hybridization. The transcription rate of cruciferin increased about 2-fold, and the transcription rate of napin increased about 3- to 4-fold in ABA-treated embryos compared to embryos cultured on basal medium. This increase in transcription rate is consistent with the increases in RNA levels which are seen in parallel experiments. In the same experiments, the transcription rates of actin and the rRNA genes were unaffected by ABA. In reinduction experiments, embryos which were switched from basal medium to medium containing ABA at 12 or 24 h showed an increase in transcription rate of the seed storage protein genes to the same level as those which were cultured on ABA at time 0

  9. Three WRKY transcription factors additively repress abscisic acid and gibberellin signaling in aleurone cells.

    Zhang, Liyuan; Gu, Lingkun; Ringler, Patricia; Smith, Stanley; Rushton, Paul J; Shen, Qingxi J

    2015-07-01

    Members of the WRKY transcription factor superfamily are essential for the regulation of many plant pathways. Functional redundancy due to duplications of WRKY transcription factors, however, complicates genetic analysis by allowing single-mutant plants to maintain wild-type phenotypes. Our analyses indicate that three group I WRKY genes, OsWRKY24, -53, and -70, act in a partially redundant manner. All three showed characteristics of typical WRKY transcription factors: each localized to nuclei and yeast one-hybrid assays indicated that they all bind to W-boxes, including those present in their own promoters. Quantitative real time-PCR (qRT-PCR) analyses indicated that the expression levels of the three WRKY genes varied in the different tissues tested. Particle bombardment-mediated transient expression analyses indicated that all three genes repress the GA and ABA signaling in a dosage-dependent manner. Combination of all three WRKY genes showed additive antagonism of ABA and GA signaling. These results suggest that these WRKY proteins function as negative transcriptional regulators of GA and ABA signaling. However, different combinations of these WRKY genes can lead to varied strengths in suppression of their targets. PMID:26025535

  10. Abscisic acid and other plant hormones: Methods to visualize distribution and signaling

    Waadt, Rainer; Hsu, Po-Kai; Schroeder, Julian I.

    2015-01-01

    The exploration of plant behavior on a cellular scale in a minimal invasive manner is key to understanding plant adaptations to their environment. Plant hormones regulate multiple aspects of growth and development and mediate environmental responses to ensure a successful life cycle. To monitor the dynamics of plant hormone actions in intact tissue, we need qualitative and quantitative tools with high temporal and spatial resolution. Here, we describe a set of biological instruments (reporter...

  11. Effect of abscisic acid on photosynthetic parameters during ex vitro transfer of micropropagated tobacco plantlets

    Pospíšilová, Jana; Synková, Helena; Haisel, Daniel; Baťková, Petra

    2009-01-01

    Roč. 53, č. 1 (2009), s. 11-20. ISSN 0006-3134 R&D Projects: GA ČR GA522/07/0227 Institutional research plan: CEZ:AV0Z50380511 Keywords : carotenoids * chlorophyll contents * chlorophyll fluorescence Subject RIV: ED - Physiology Impact factor: 1.656, year: 2009

  12. Role of abscisic acid and proline in salinity tolerance of wheat genotypes

    Wheat genotypes were evaluated for salinity tolerance under 3 diverse environments of Yar Hussain, Baboo Dehari (District Swabi KPK Pakistan) and Khitab Koroona (District Charsadda KPK Pakistan). Eleven genotypes (Local, SR-24, SR-25, SR-7, SR-22, SR-4, SR-20, SR-19, SR-2, SR-23 and SR-40) were tested for their salinity tolerance. These locations had different salinity profile (i.e. Yar Hussain, EC. 3-3.5 dS m/sup -1/; Baboo Dehari, EC. 4-4.5 dS m/sup -1/ and Khitab Koroona, EC. 5-5.30 dSm/sup -1/). Different locations and wheat genotypes had a significant (p < 0.05) effect on endogenous shoot proline, shoot ABA (3, 6 and 9 weeks after emergence) and straw yield. Maximum endogenous shoot proline and ABA levels (3, 6 and 9 weeks after emergence) were recorded in genotype SR-40 followed by genotype SR-23. The results further indicated that minimum endogenous shoot proline and ABA concentrations (3, 6 and 9 weeks after emergence) were recorded at Yar Hussain. Maximum endogenous shoot proline and ABA concentration (3, 6 and 9 weeks after emergence) were observed at Khitab Koroona. (author)

  13. Interaction of Cytokinins and Abscisic Acid During Regulation of Stomatal Opening in Bean Leaves

    Pospíšilová, Jana

    2003-01-01

    Roč. 41, č. 1 (2003), s. 49-56. ISSN 0300-3604 R&D Projects: GA ČR GA522/02/1099 Institutional research plan: CEZ:AV0Z5038910 Keywords : benzyladenine * net photosynthetic rate * Phaseolus vulgaris Subject RIV: EF - Botanics Impact factor: 0.661, year: 2003

  14. Calcium partitioning and allocation in tomato plants and fruit in response to abscisic acid application

    Although Ca2+ is believed to move in the plant exclusively through the xylem, the mechanisms regulating Ca2+ partitioning and allocation in tomato plants and fruit remain poorly understood. The objectives of this study were to determine Ca2+ partitioning and allocation in tomato plants and fruit in ...

  15. Abscisic Acid-Cytokinin Antagonism Modulates Resistance Against Pseudomonas syringae in Tobacco

    Grosskinsky, D. K.; van der Graaff, E.; Roitsch, Thomas

    2015-01-01

    Roč. 104, č. 12 (2015), s. 1283-1288. ISSN 0031-949X Institutional support: RVO:67179843 Keywords : Nicotiana tabacum * plant-pathogen interaction Subject RIV: EH - Ecology, Behaviour Impact factor: 3.119, year: 2014

  16. CPK12: A Ca2+-dependent protein kinase balancer in abscisic acid signaling

    Zhao, Rui; Wang, Xiao-Fang; Zhang, Da-Peng

    2011-01-01

    Ca2+ is believed to be a critical second messenger in ABA signal transduction. Ca2+-dependent protein kinases (CDPKs) are the best characterized Ca2+ sensors in plants. Recently, we identified an Arabidopsis CDPK member CPK12 as a negative regulator of ABA signaling in seed germination and post-germination growth, which reveals that different members of the CDPK family may constitute a regulation loop by functioning positively and negatively in ABA signal transduction. We observed that both R...

  17. Involvement of Arabidopsis RACK1 in Protein Translation and Its Regulation by Abscisic Acid

    Guo, Jianjun [University of British Columbia, Vancouver; Wang, Shucai [University of British Columbia, Vancouver; Valerius, Oliver [Universitaet Goettingen, Goettingen, Germany; Hall, Hardy [University of British Columbia, Vancouver; Zeng, Qingning [University of British Columbia, Vancouver; Li, Jian-Feng [Harvard University; Weston, David [ORNL; Ellis, Brian [University of British Columbia, Vancouver; Chen, Jay [ORNL

    2011-01-01

    Earlier studies have shown that RACK1 functions as a negative regulator of ABA responses in Arabidopsis, but the molecular mechanism of the action of RACK1 in these processes remains elusive. Global gene expression profiling revealed that approximately 40% of the genes affected by ABA treatment were affected in a similar manner by the rack1 mutation, supporting the view that RACK1 is an important regulator of ABA responses. On the other hand, co-expression analysis revealed that >80% of the genes co-expressed with RACK1 encode ribosome proteins, implying a close relationship between RACK1 s function and the ribosome complex. These results implied that the regulatory role for RACK1 in ABA responses may be partially due to its putative function in protein translation, which is one of the major cellular processes that mammalian and yeast RACK1 is involved in. Consistently, all three Arabidopsis RACK1 homologous genes, namely RACK1A, RACK1B and RACK1C, complemented the growth defects of the S. cerevisiae cpc2/rack1 mutant. In addition, RACK1 physically interacts with Arabidopsis Eukaryotic Initiation Factor 6 (eIF6), whose mammalian homologue is a key regulator of 80S ribosome assembly. Moreover, rack1 mutants displayed hypersensitivity to anisomycin, an inhibitor of protein translation, and displayed characteristics of impaired 80S functional ribosome assembly and 60S ribosomal subunit biogenesis in a ribosome profiling assay. Gene expression analysis revealed that ABA inhibits the expression of both RACK1 and eIF6. Taken together, these results suggest that RACK1 may be required for normal production of 60S and 80S ribosomes and that its action in these processes may be regulated by ABA.

  18. Purification and Analysis of Abscisic Acid-Specifically-Inducible Proteins from Rice Callus

    2007-01-01

    Two ABA-specifically-inducible proteins from rice callus were isolated and purified by precipitation with 65-100 % saturated(NH4)2SO4, followed by the DEAE-sepharose, TSK-gel, and two-dimension electrophoresis. Iso-electric points (pl) of the proteins with the same molecular mass (24.5 kD) were 6.1 and 6.9, respectively. The Western blot analysis indicated that the proteins expressed in different tissues were obviously different. The A1 (pl 6.1) protein was only detected in calli treated with ABA and seed embryos (SE).However, the A2 (pl 6.9) protein was found not only in the calli treated with ABA and SE, but also in the white dry callus. Thus it suggested that the two proteins might play some important roles in the processes of seed embryo (or somatic embryo) formation.

  19. Sequencing and Transcriptional Analysis of the Biosynthesis Gene Cluster of Abscisic Acid-Producing Botrytis cinerea

    Tao Gong; Dan Shu; Jie Yang; Zhong-Tao Ding; Hong Tan

    2014-01-01

    Botrytis cinerea is a model species with great importance as a pathogen of plants and has become used for biotechnological production of ABA. The ABA cluster of B. cinerea is composed of an open reading frame without significant similarities (bcaba3), followed by the genes (bcaba1 and bcaba2) encoding P450 monooxygenases and a gene probably coding for a short-chain dehydrogenase/reductase (bcaba4). In B. cinerea ATCC58025, targeted inactivation of the genes in the cluster suggested at least ...

  20. Abscisic acid content of a nondormant sunflower (Helianthus annuus L.) mutant

    A sunflower (Helianthus annuus L.) mutant was observed in the progeny of a cross between the sunflower cultivar HA 89 and an amphiploid of a H. divaricatus L. x P21 cross that exhibited loss of dormancy induction in the developing embryo. Seeds of this mutant frequently germinate on the head about 4...

  1. Polyethylene glycol and abscisic acid improve maturation and regeneration of Panax ginseng somatic embryos

    Langhansová, Lenka; Konrádová, H.; Vaněk, Tomáš

    2004-01-01

    Roč. 22, - (2004), s. 725-730. ISSN 0721-7714 R&D Projects: GA ČR GP521/02/P064; GA MŠk OC 843.10; GA MŠk ME 671 Institutional research plan: CEZ:AV0Z4055905 Keywords : ABA * Panax ginseng * somatic embryogenesis Subject RIV: EI - Biotechnology ; Bionics Impact factor: 1.457, year: 2004

  2. Stomatal and non-stomatal effects of exogenous abscisic acid during plant hardening

    Pospíšilová, Jana; Synková, Helena; Haisel, Daniel; Baťková, Petra

    2008-01-01

    Roč. 133, - (2008), P09-131. ISSN 0031-9317 R&D Projects: GA ČR GA522/07/0227 Institutional research plan: CEZ:AV0Z50380511 Keywords : phytohormones * micropropagation * photosynthesis Subject RIV: ED - Physiology Impact factor: 2.334, year: 2008

  3. Increased Putamen and Callosal Motor Subregion in Treatment-Naive Boys with Tourette Syndrome Indicates Changes in the Bihemispheric Motor Network

    Roessner, Veit; Overlack, Sebastian; Schmidt-Samoa, Carsten; Baudewig, Jurgen; Dechent, Peter; Rothenberger, Aribert; Helms, Gunther

    2011-01-01

    Background: Despite an increasing number of studies, findings of structural brain alterations in patients with Tourette syndrome are still inconsistent. Several confounders (comorbid conditions, medication, gender, age, IQ) might explain these discrepancies. In the present study, these confounders were excluded to identify differences in basal…

  4. Genes encoding a callose synthase and phytochrome A are adjacent to a MAP3Ka-like gene in Beta vulgaris USH20

    MAP3Ka encodes a key conserved protein kinase responsible for orchestrating a rapid cascade of cellular events ultimately leading to localized cell death. Hypersensitive response, as it is termed, enables genetically-resistant plants to limit microbial invasion under the right environmental conditio...

  5. Enhanced expression of hepatocyte-specific microRNAs in valproic acid mediated hepatic trans-differentiation of human umbilical cord derived mesenchymal stem cells.

    Raut, Akshata; Khanna, Aparna

    2016-05-01

    MicroRNAs (miRNAs) play an important role in the control of cell fate determination during differentiation. In this study, we analyzed the expression pattern of microRNAs (miRNAs) during hepatic trans-differentiation. The protocol employed the use of histone deacetylase inhibitor (HDACI), valproic acid (VPA) to induce hepatic trans-differentiation of human umbilical cord Wharton's jelly derived mesenchymal stem cells (hUC-MSCs). The differentiated hepatocyte like cells (HLCs) from hUC-MSCs shared typical characteristics with mature hepatocytes, including morphology, expression of hepatocyte -specific genes at the molecular and cellular level. Moreover, the functionality of HLCs was confirmed through various liver function tests such as periodic acid-Schiff (PAS) stain for glycogen accumulation, enzyme-linked immunosorbent assay (ELISA) for synthesis of albumin and release of urea. The aim of the present work was to examine the effect of VPA treatment on miRNA expression during hepatic trans-differentiation. The analysis at miRNA level showed that there was a significant increase in expression of miRNAs involved in hepatic differentiation, due to VPA pre-treatment during differentiation. The study, thus demonstrated that improved expression of hepatocyte-specific miRNAs, miR-23b cluster (miR-27b-3p, miR-24-1-5p and miR-23b-3p), miR-30a-5p, miR-26a-5p, miR-148a-3p, miR-192-5p, miR-122-5p due to VPA pre-treatment contributed to a more efficient hepatic trans-differentiation from hUC-MSCs. The putative targets of these upregulated miRNAs were predicted using Bioinformatics analysis. Finally, miR-122-5p, highly upregulated miRNA during hepatic differentiation, was selected for target verification studies. Thus, this study also provides the basis for the function of miR-122-5p during hepatic differentiation of hUC-MSCs. PMID:27001466

  6. 5-aminolevulinic acid-mediated photodynamic therapy of intraepithelial neoplasia and human papillomavirus of the uterine cervix--a new experimental approach.

    Wierrani, F; Kubin, A; Jindra, R; Henry, M; Gharehbaghi, K; Grin, W; Söltz-Szötz, J; Alth, G; Grünberger, W

    1999-01-01

    The aim of this study was to treat patients for ectocervical dysplasia [cervical intraepithelial neoplasia (CIN) grades 1 and 2] and associated human papilloma virus (HPV) infections with photodynamic therapy (PDT). In 20 patients, 5-aminolevulinic acid (5-ALA, 12% w/v) was applied topically with a cervical cap 8 h prior to illumination. A thermal light source (150 W halogen lamp) emitting a broadband red light (total energy: 100 J/cm2, fluence rate: 90 mW/cm2) was used for superficial illumination of the portio. In addition, an Nd:YAG pumped dye laser (652 nm) was used to illuminate the cervical canal (total energy: 50 J/cm2, fluence rate: 300 mW/cm2). Preliminary results of follow-ups at 1, 3, 6, and 9 months posttherapy showed a cytological improvement in the grading of the PAP smears in 19 patients and the eradication of cervical HPV in 80%. These results demonstrate that ectocervical dysplasia and associated HPV infections can be treated by PDT. PMID:10403907

  7. All Trans-Retinoic Acid Mediates MED28/HMG Box-Containing Protein 1 (HBP1)/β-Catenin Signaling in Human Colorectal Cancer Cells.

    Lee, Ming-Fen; Hsieh, Nien-Tsu; Huang, Chun-Yin; Li, Chun-I

    2016-08-01

    Vitamin A is required for normal body function, including vision, epithelial integrity, growth, and differentiation. All trans-retinoic acid (ATRA), a family member of vitamin A, has been explored in treating acute promyelocytic leukemia and other types of cancer. Dysregulated Wnt/β-catenin signaling and disrupted cadherin-catenin complex often contribute to colorectal malignancy. MED28, a mammalian Mediator subunit, is found highly expressed in breast and colorectal cancers. Our laboratory has also reported that MED28 regulates cell growth, migration, and invasion in human breast cancer cells. In the current study we investigated the effect of ATRA on MED28 and Wnt/β-catenin signaling in colorectal cancer. HCT116, HT29, SW480, and SW620, four human colorectal cancer cell lines representing different stages of carcinogenesis and harboring critical genetic changes, were employed. Our data indicated that regardless of genetic variations among these cells, suppression of MED28 reduced the expression of cyclin D1, c-Myc, and nuclear β-catenin, but increased the expression of E-cadherin and HMG box-containing protein 1 (HBP1) where HBP1 has been described as a negative regulator of the Wnt/β-catenin signaling. The reporter activity of an HBP1 promoter increased upon MED28 knockdown, but decreased upon MED28 overexpression. ATRA reduced the expression of MED28 and mimicked the effect of MED28 suppression in down-regulating Wnt/β-catenin signaling. Taken together, ATRA can reverse the suppressive effect of MED28 on HBP1 and E-cadherin and inactivate the Wnt/β-catenin pathway in colorectal cancer, suggesting a protective effect of ATRA against colorectal cancer. J. Cell. Physiol. 231: 1796-1803, 2016. © 2015 Wiley Periodicals, Inc. PMID:26660958

  8. Acute and Long-Term Response of Dopamine Nigrostriatal Synapses to a Single Low Dose Episode of 3-Nitropropionic Acid-Mediated Chemical Hypoxia

    Crawford, Cynthia A.; Akopian, Garnik; Ring, Justin; Jakowec, Michael W.; Petzinger, Giselle M.; Andersen, Julie K.; Vittozzi-Wong, Philip; Wang, Kristie; Farley, Cristal M.; Charntikov, Sergios; Mitroi, Danut; Beal, M. Flint; Chow, Robert; Walsh, John P

    2010-01-01

    The goal of the present investigation was to determine the persistence of striatal dopaminergic dysfunction after a mild chemically-induced hypoxic event in Fisher 344 rats. To this end, we gave a single injection of the mitochondrial complex II inhibitor 3-nitropropionic acid (3-NP; 16.5 mg/kg, i.p.) to 2 month old male F344 rats and measured various indices of striatal dopaminergic functioning and lipid peroxidation over a 3 month span. Separate groups of rats were used to measure rod walki...

  9. Mutation of the NADH Oxidase Gene (nox) Reveals an Overlap of the Oxygen- and Acid-Mediated Stress Responses in Streptococcus mutans

    Derr, Adam M.; Faustoferri, Roberta C.; Betzenhauser, Matthew J.; Gonzalez, Kaisha; Marquis, Robert E.; Quivey, Robert G.

    2012-01-01

    NADH oxidase (Nox) is a flavin-containing enzyme used by Streptococcus mutans to reduce dissolved oxygen encountered during growth in the oral cavity. In this study, we characterized the role of the NADH oxidase in the oxidative and acid stress responses of S. mutans. A nox-defective mutant strain of S. mutans and its parental strain, the genomic type strain UA159, were exposed to various oxygen concentrations at pH values of 5 and 7 to better understand the adaptive mechanisms used by the or...

  10. ERKs and mitochondria-related pathways are essential for glycyrrhizic acid-mediated neuroprotection against glutamate-induced toxicity in differentiated PC12 cells

    The present study focuses on the neuroprotective effect of glycyrrhizic acid (GA, a major compound separated from Glycyrrhiza Radix, which is a crude Chinese traditional drug) against glutamate-induced cytotoxicity in differentiated PC12 (DPC12) cells. The results showed that GA treatment improved cell viability and ameliorated abnormal glutamate-induced alterations in mitochondria in DPC12 cells. GA reversed glutamate-suppressed B-cell lymphoma 2 levels, inhibited glutamate-enhanced expressions of Bax and cleaved caspase 3, and reduced cytochrome C (Cyto C) release. Exposure to glutamate strongly inhibited phosphorylation of AKT (protein kinase B) and extracellular signal-regulated kinases (ERKs); however, GA pretreatment enhanced activation of ERKs but not AKT. The presence of PD98059 (a mitogen-activated protein/extracellular signal-regulated kinase kinase [MEK] inhibitor) but not LY294002 (a phosphoinositide 3-kinase [PI3K] inhibitor) diminished the potency of GA for improving viability of glutamate-exposed DPC12 cells. These results indicated that ERKs and mitochondria-related pathways are essential for the neuroprotective effect of GA against glutamate-induced toxicity in DPC12 cells. The present study provides experimental evidence supporting GA as a potential therapeutic agent for use in the treatment of neurodegenerative diseases

  11. Optical Resolution of DL-Tartaric Acid Mediated by Diastereomeric Salts Crystallization: A Useful Method for Exploring and Optimizing Experimental Conditions

    2002-01-01

    A response surface modeling approach for simultaneous optimization of optical purity and yield wasapplied to the resolution of tartaric acid to study the effects of both the amount of the solvent and the amountof the resolving agent α-methylbenzyl amine on the resolution results. The direction of changing the experimen-tal conditions was determined from the initial response study, and expected high yield of the pure L(+)-tartaricacid-L(-)-α-methylbenzyl amine salt was obtained.

  12. Fasting induces IL-1 resistance and free fatty acid-mediated up-regulation of IL-1R2 and IL-1RA

    jenifer j joesting

    2014-07-01

    Full Text Available Objective: Weight loss is a near societal obsession and many diet programs use significant calorie restriction (CR including fasting/short term starvation to generate rapid effects. Fasting is also a well-recognized cause of immunosuppression especially within the innate immune system. In this study, we sought to determine if the IL-1 arm of the neuroimmune system was down-regulated by a 24 hr fast and how fasting might generate this effect. Design: Mice were allowed ad libitum access to food or had food withheld for 24 hrs. Expression of the endogenous IL-1 antagonists IL-1 receptor type 2 (IL-1R2 and IL-1 receptor antagonist (IL-1RA were determined as were sickness behaviors before and after IL-1 administration.Results: Fasting markedly increased gene expression of IL-1R2 (83-fold in adipose tissue, 9.5-fold in liver and IL-1RA (68-fold in liver. Fasted mice were protected from IL-1-induced weight loss, hypoglycemia, loss of locomotor and social anxiety. These protections were coupled to a large positive interaction of fasting and IL-1 on IL-1R2 gene expression in adipose tissue and liver (2.6-fold and 1.6-fold, respectively. Fasting not only increased IL-1RA and IL-1R2 protein 2.5-fold and 3.2-fold, respectively, in liver; but also increased IL-1R2 1.8-fold in adipose tissue. Fasting, in turn, triggered a 2.4-fold increase in plasma free-fatty acids (FFAs and a 2.1-fold increase in plasma corticosterone. Inhibition, of glucocorticoid action with mifepristone did not impact fasting-dependent IL-1R2 or IL-1RA gene expression. Administration of the FFA, palmitate, to mice increased liver IL-1R2 and IL-1RA gene expression by 14-fold and 11-fold, respectively. Conclusion: These findings indicate that fasting augments expression of endogenous IL-1 antagonists inducing IL-1 resistance. Fasting-induced increases in plasma FFAs appears to be a signal that drives immunosuppression during fasting/short term starvation.

  13. P-type ATPase TAT-2 negatively regulates monomethyl branched-chain fatty acid mediated function in post-embryonic growth and development in C. elegans.

    Emylie Seamen

    2009-08-01

    Full Text Available Monomethyl branched-chain fatty acids (mmBCFAs are essential for Caenorhabditis elegans growth and development. To identify factors acting downstream of mmBCFAs for their function in growth regulation, we conducted a genetic screen for suppressors of the L1 arrest that occurs in animals depleted of the 17-carbon mmBCFA C17ISO. Three of the suppressor mutations defined an unexpected player, the P-type ATPase TAT-2, which belongs to the flippase family of proteins that are implicated in mediating phospholipid bilayer asymmetry. We provide evidence that TAT-2, but not other TAT genes, has a specific role in antagonizing the regulatory activity of mmBCFAs in intestinal cells. Interestingly, we found that mutations in tat-2 also suppress the lethality caused by inhibition of the first step in sphingolipid biosynthesis. We further showed that the fatty acid side-chains of glycosylceramides contain 20%-30% mmBCFAs and that this fraction is greatly diminished in the absence of mmBCFA biosynthesis. These results suggest a model in which a C17ISO-containing sphingolipid may mediate the regulatory functions of mmBCFAs and is negatively regulated by TAT-2 in intestinal cells. This work indicates a novel connection between a P-type ATPase and the critical regulatory function of a specific fatty acid.

  14. ERKs and mitochondria-related pathways are essential for glycyrrhizic acid-mediated neuroprotection against glutamate-induced toxicity in differentiated PC12 cells

    Wang, D. [School of Life Sciences, Jilin University, Changchun (China); The State Engineering Laboratory of AIDS Vaccine, Jilin University, Changchun (China); Guo, T.Q. [School of Life Sciences, Jilin University, Changchun (China); Wang, Z.Y. [State Key Laboratory of Theoretical and Computational Chemistry, Jilin University, Changchun (China); Lu, J.H.; Liu, D.P.; Meng, Q.F.; Xie, J. [School of Life Sciences, Jilin University, Changchun (China); Zhang, X.L. [Faculty of ScienceNational University of Singapore (Singapore); Liu, Y. [School of Life Sciences, Jilin University, Changchun (China); Teng, L.S. [School of Life Sciences, Jilin University, Changchun (China); The State Engineering Laboratory of AIDS Vaccine, Jilin University, Changchun (China)

    2014-07-25

    The present study focuses on the neuroprotective effect of glycyrrhizic acid (GA, a major compound separated from Glycyrrhiza Radix, which is a crude Chinese traditional drug) against glutamate-induced cytotoxicity in differentiated PC12 (DPC12) cells. The results showed that GA treatment improved cell viability and ameliorated abnormal glutamate-induced alterations in mitochondria in DPC12 cells. GA reversed glutamate-suppressed B-cell lymphoma 2 levels, inhibited glutamate-enhanced expressions of Bax and cleaved caspase 3, and reduced cytochrome C (Cyto C) release. Exposure to glutamate strongly inhibited phosphorylation of AKT (protein kinase B) and extracellular signal-regulated kinases (ERKs); however, GA pretreatment enhanced activation of ERKs but not AKT. The presence of PD98059 (a mitogen-activated protein/extracellular signal-regulated kinase kinase [MEK] inhibitor) but not LY294002 (a phosphoinositide 3-kinase [PI3K] inhibitor) diminished the potency of GA for improving viability of glutamate-exposed DPC12 cells. These results indicated that ERKs and mitochondria-related pathways are essential for the neuroprotective effect of GA against glutamate-induced toxicity in DPC12 cells. The present study provides experimental evidence supporting GA as a potential therapeutic agent for use in the treatment of neurodegenerative diseases.

  15. Siderocalin/Lcn2/NGAL/24p3 does not drive apoptosis through gentisic acid mediated iron withdrawal in hematopoietic cell lines.

    Colin Correnti

    Full Text Available Siderocalin (also lipocalin 2, NGAL or 24p3 binds iron as complexes with specific siderophores, which are low molecular weight, ferric ion-specific chelators. In innate immunity, siderocalin slows the growth of infecting bacteria by sequestering bacterial ferric siderophores. Siderocalin also binds simple catechols, which can serve as siderophores in the damaged urinary tract. Siderocalin has also been proposed to alter cellular iron trafficking, for instance, driving apoptosis through iron efflux via BOCT. An endogenous siderophore composed of gentisic acid (2,5-dihydroxybenzoic acid substituents was proposed to mediate cellular efflux. However, binding studies reported herein contradict the proposal that gentisic acid forms high-affinity ternary complexes with siderocalin and iron, or that gentisic acid can serve as an endogenous siderophore at neutral pH. We also demonstrate that siderocalin does not induce cellular iron efflux or stimulate apoptosis, questioning the role siderocalin plays in modulating iron metabolism.

  16. PNA-based DNA assay with attomolar detection limit based on polygalacturonic acid mediated in-situ deposition of metallic silver on a gold electrode

    An electrochemical method is described for the ultrasensitive determination of sequence-specific DNA by using polysaccharide-mediated in-situ deposition of metallic silver on a gold electrode. Specifically, a thiolated peptide nucleic acid (PNA) is immobilized on the gold electrode via formation of a self-assembled monolayer. Following hybridization between PNA and target single-stranded DNA (ssDNA), polygalacturonic acid (PGUA) is introduced to the PNA/DNA heteroduplexes via phosphate-zirconium-carboxylate coordination interaction. Next, the vicinal hydroxy groups of the polysaccharide backbone are cleaved and oxidized into aldehyde groups. These act as reductants and convert added silver ions into metallic silver which in-situ deposits on the gold electrode, and then is stripped off electrochemically into a solution of KCl where it is accurately determined by differential pulse voltammetry. Under optimal conditions, this assay exhibits a wide linear response range in that the stripping current is related to the logarithm of the concentration of target ssDNA in the 0.1 fM to 10 pM range, with a detection limit as low as 2.5 aM. The method displays excellent specificity in clearly differentiating mismatched oligonucleotide fragments. We therefore believe that this method has a large potential in terms of genotyping of single-nucleotide polymorphism. Moreover, this kind of signal amplification possesses a very large capability with respect to ultrasensitive quantitation of low-abundant biomarkers. (author)

  17. Site-Specific Enhancement of γ-Aminobutyric Acid-Mediated Inhibition of Neural Activity by Ethanol in the Rat Medial Septal Area1

    GIVENS, BENNET S.; Breese, George R.

    1990-01-01

    Because of uncertainty concerning the interaction of ethanol with γ-aminobutyric acid (GABA) receptor-mediated events, the present work was designed to investigate the effect of ethanol on GABA transmission in the rat septal area using behavioral and electrophysiological techniques. Microinjection of the GABAA agonist muscimol into the medial septal area (MSA) enhanced, and bicuculline administration antagonized, ethanol-induced impairment of the aerial righting reflex. Microinjection of thes...

  18. Site-specific enhancement of gamma-aminobutyric acid-mediated inhibition of neural activity by ethanol in the rat medial septal area.

    Givens, B S; Breese, G R

    1990-08-01

    Because of uncertainty concerning the interaction of ethanol with gamma-aminobutyric acid (GABA) receptor-mediated events, the present work was designed to investigate the effect of ethanol on GABA transmission in the rat septal area using behavioral and electrophysiological techniques. Microinjection of the GABAA agonist muscimol into the medial septal area (MSA) enhanced, and bicuculline administration antagonized, ethanol-induced impairment of the aerial righting reflex. Microinjection of these drugs into the lateral septum (LSi) did not influence this measure of ethanol-induced sedation. Furthermore, intraseptal injections of muscimol or bicuculline in saline-treated rats had no effect on the aerial righting reflex. These data suggest that the MSA plays a critical modulatory role in the sedative actions of ethanol. To assess the effect of ethanol on muscimol responses in the MSA and LSi at the cellular level, GABA was applied by iontophoresis to rhythmically bursting neurons of the MSA and to cells in the LSi. The magnitude of the resultant inhibition by GABA on these cells was assessed before and after systemic administration of ethanol. Ethanol enhanced GABA-mediated inhibition of MSA neural activity, but did not alter GABA-mediated inhibition of cellular activity in the LSi. In contrast, the inhibition of cellular activity in the MSA, caused by a maximally effective concentration of the benzodiazepine flurazepam, was not altered by ethanol. Other work in the MSA demonstrated that electrical stimulation of the fimbria caused an inhibition of ongoing single unit activity that was reduced by concurrent application of bicuculline. The duration of this electrically elicited inhibition in the MSA was enhanced after ethanol injection and then recovered to base-line levels. In addition, ethanol (1.5 mg/kg) caused an enhancement of the inhibition induced by nipecotic acid, a GABA uptake inhibitor. These findings demonstrate that GABA-mediated neural inhibition is enhanced by ethanol in the MSA but not the LSi, indicating that the actions of ethanol on GABA-induced inhibition can be site specific. It is proposed that the cellular action of ethanol may depend upon a specific molecular composition of the GABA receptor complex which may vary at selected sites in the brain. PMID:2166794

  19. Bile-acid-mediated decrease in endoplasmic reticulum stress: a potential contributor to the metabolic benefits of ileal interposition surgery in UCD-T2DM rats

    Bethany P. Cummings

    2013-03-01

    Post-operative increases in circulating bile acids have been suggested to contribute to the metabolic benefits of bariatric surgery; however, their mechanistic contributions remain undefined. We have previously reported that ileal interposition (IT surgery delays the onset of type 2 diabetes in UCD-T2DM rats and increases circulating bile acids, independently of effects on energy intake or body weight. Therefore, we investigated potential mechanisms by which post-operative increases in circulating bile acids improve glucose homeostasis after IT surgery. IT, sham or no surgery was performed on 2-month-old weight-matched male UCD-T2DM rats. Animals underwent an oral fat tolerance test (OFTT and serial oral glucose tolerance tests (OGTT. Tissues were collected at 1.5 and 4.5 months after surgery. Cell culture models were used to investigate interactions between bile acids and ER stress. IT-operated animals exhibited marked improvements in glucose and lipid metabolism, with concurrent increases in postprandial glucagon-like peptide-1 (GLP-1 secretion during the OFTT and OGTTs, independently of food intake and body weight. Measurement of circulating bile acid profiles revealed increases in circulating total bile acids in IT-operated animals, with a preferential increase in circulating cholic acid concentrations. Gut microbial populations were assessed as potential contributors to the increases in circulating bile acid concentrations, which revealed proportional increases in Gammaproteobacteria in IT-operated animals. Furthermore, IT surgery decreased all three sub-arms of ER stress signaling in liver, adipose and pancreas tissues. Amelioration of ER stress coincided with improved insulin signaling and preservation of β-cell mass in IT-operated animals. Incubation of hepatocyte, adipocyte and β-cell lines with cholic acid decreased ER stress. These results suggest that postoperative increases in circulating cholic acid concentration contribute to improvements in glucose homeostasis after IT surgery by ameliorating ER stress.

  20. Bile-acid-mediated decrease in endoplasmic reticulum stress: a potential contributor to the metabolic benefits of ileal interposition surgery in UCD-T2DM rats

    Cummings, Bethany P.; Ahmed Bettaieb; Graham, James L.; Jaehyoung Kim; Fangrui Ma; Noreene Shibata; Stanhope, Kimber L.; Cecilia Giulivi; Frederik Hansen; Jacob Jelsing; Niels Vrang; Mark Kowala; Chouinard, Michael L.; Haj, Fawaz G.; Havel, Peter J.

    2012-01-01

    SUMMARY Post-operative increases in circulating bile acids have been suggested to contribute to the metabolic benefits of bariatric surgery; however, their mechanistic contributions remain undefined. We have previously reported that ileal interposition (IT) surgery delays the onset of type 2 diabetes in UCD-T2DM rats and increases circulating bile acids, independently of effects on energy intake or body weight. Therefore, we investigated potential mechanisms by which post-operative increas...

  1. Evidence for rapid inter- and intramolecular chlorine transfer reactions of histamine and carnosine chloramines: implications for the prevention of hypochlorous-acid-mediated damage.

    Pattison, David I; Davies, Michael J

    2006-07-01

    Hypochlorous acid (HOCl) is a powerful oxidant generated from H(2)O(2) and Cl(-) by the heme enzyme myeloperoxidase, which is released from activated leukocytes. HOCl possesses potent antibacterial properties, but excessive production can lead to host tissue damage that is implicated in a wide range of human diseases (e.g., atherosclerosis). Histamine and carnosine have been proposed as protective agents against such damage. However, as recent studies have shown that histidine-containing compounds readily form imidazole chloramines that can rapidly chlorinate other targets, it was hypothesized that similar reactions may occur with histamine and carnosine, leading to propagation, rather than prevention, of HOCl-mediated damage. In this study, the reactions of HOCl with histamine, histidine, carnosine, and other compounds containing imidazole and free amine sites were examined. In all cases, rapid formation (k, 1.6 x 10(5) M(-)(1) s(-)(1)) of imidazole chloramines was observed, followed by chlorine transfer to yield more stable, primary chloramines (R-NHCl). The rates of most of these secondary reactions are dependent upon substrate concentrations, consistent with intermolecular mechanisms (k, 10(3)-10(4) M(-)(1) s(-)(1)). However, for carnosine, the imidazole chloramine transfer rates are independent of the concentration, indicative of intramolecular processes (k, 0.6 s(-)(1)). High-performance liquid chromatography studies show that in all cases the resultant R-NHCl species can slowly chlorinate N-alpha-acetyl-Tyr. Thus, the current data indicate that the chloramines formed on the imidazole and free amine groups of these compounds can oxidize other target molecules but with limited efficiency, suggesting that histamine and particularly carnosine may be able to limit HOCl-mediated oxidation in vivo. PMID:16800640

  2. Transcriptional profiling of the Arabidopsis abscission mutant hae hsl2 by RNA-Seq

    Niederhuth Chad E

    2013-01-01

    Full Text Available Abstract Background Abscission is a mechanism by which plants shed entire organs in response to both developmental and environmental signals. Arabidopsis thaliana, in which only the floral organs abscise, has been used extensively to study the genetic, molecular and cellular processes controlling abscission. Abscission in Arabidopsis requires two genes that encode functionally redundant receptor-like protein kinases, HAESA (HAE and HAESA-LIKE 2 (HSL2. Double hae hsl2 mutant plants fail to abscise their floral organs at any stage of floral development and maturation. Results Using RNA-Seq, we compare the transcriptomes of wild-type and hae hsl2 stage 15 flowers, using the floral receptacle which is enriched for abscission zone cells. 2034 genes were differentially expressed with a False Discovery Rate adjusted p INFLORESCENCE DEFICIENT IN ABSCISSION (ida mutants shows that many of the same genes are co-regulated by IDA and HAE HSL2 and support the role of IDA in the HAE and HSL2 signaling pathway. Comparison to microarray data from stamen abscission zones show distinct patterns of expression of genes that are dependent on HAE HSL2 and reveal HAE HSL2- independent pathways. Conclusion HAE HSL2-dependent and HAE HSL2-independent changes in genes expression are required for abscission. HAE and HSL2 affect the expression of cell wall modifying and defense related genes necessary for abscission. The HAE HSL2-independent genes also appear to have roles in abscission and additionally are involved in processes such as hormonal signaling, senescence and callose deposition.

  3. Molecular and genetic analyses of the PP2C-ABA receptor interaction in the abscisic acid signaling pathway.

    Antoni Alandes, Regina

    2013-01-01

    La fitohormona ácido abscísico (ABA) juega un papel crucial en el control de la respuesta a estrés y en la regulación del crecimiento y desarrollo de la planta. La unión del ABA a los receptores intracelulares PYR/PYL/RCAR conlleva la inhibición de las PP2Cs del clado A tales como ABI1 o HAB1, causando la activación de la ruta de señalización del ABA. Para obtener más información en la señalización del ABA nos hemos centrado en la caracterización de miembros de estas dos famil...

  4. Ethylene Interacts with Abscisic Acid to Regulate Endosperm Rupture during Germination: A Comparative Approach Using Lepidium sativum and Arabidopsis thaliana

    Linkies, A.; Müller, L.; Morris, K.; Turečková, Veronika; Wenk, M.; Cadman, C. S. C.; Corbineau, F.; Strnad, Miroslav; Lynn, J. R .; Finch-Savage, W. E.; Leubner-Metzger, G.

    2009-01-01

    Roč. 21, č. 12 (2009), s. 3803-3822. ISSN 1040-4651 Institutional research plan: CEZ:AV0Z50380511 Keywords : SEED DORMANCY RELEASE * GIBBERELLIN BIOSYNTHESIS * FEEDBACK-REGULATION Subject RIV: EF - Botanics Impact factor: 9.293, year: 2009

  5. Modulation of Root Signals in Relation to Stomatal Sensitivity to Root-sourced Abscisic Acid in Drought-affected Plants

    2007-01-01

    Stomatal sensitivity to root signals induced by soil drying may vary between environments and plant species. This is likely central role in root to shoot signaling. pH and hydraulic signals may interact with ABA signals and thus, jointly regulate stomatal responses to changed soil water status. pH itself can be modified by several factors, among which the chemical compositions In the xylem stream and the live cells surrounding the vessels play crucial roles. In addition to the xylem pH,more attention should be paid to the direct modulation of leaf apoplastic pH, because many chemical compositions might strongly modify the leaf apoplastlc pH while having no significant effect on the xylem pH. The direct modulation of the ABA signal intensity may be more important for the regulation of stomatal responses to soil drying than the ABA signal per se.The ABA signal is also regulated by the ABA catabolism and the supply of precursors to the roots If a sustained root to shoot communication of soil drying operates at the whole plant level. More importantly, ABA catabolism could play crucial roles In the determination of the fate of the ABA signal and thereby control the stomatal behavior of the root-sourced ABA signal.

  6. Acclimation of plantlets to ex vitro conditions: effects of air humidity, irradiance, CO2 concentration and abscisic acid

    Pospíšilová, Jana; Synková, Helena; Haisel, Daniel; Semorádová, Šárka

    2007-01-01

    Roč. 748, - (2007), s. 29-38. ISSN 0567-7572 R&D Projects: GA ČR GA522/02/1099; GA ČR GA522/07/0227 Institutional research plan: CEZ:AV0Z50380511 Source of funding: V - iné verejné zdroje ; V - iné verejné zdroje Keywords : chlorophyll fluorescence * micropropagation * photoinhibition * photosynthesis * stomatal conductance * transpiration rate * water relations Subject RIV: ED - Physiology

  7. Genetic Analysis of Ca2+ Priming in Arabidopsis Guard Cell Stomatal Closure in Response to the Drought Hormone Abscisic Acid

    Stephan, Aaron B.

    2014-11-30

    A primary objective of modern agriculture and biofuel production is to utilize arable land to its fullest potential. However, sub-optimal growing conditions—arising from abiotic stresses such as drought, soil salinity, low humidity, cold, and heat—reduce crop yield and quality. Optimal yield under both stressed and non-stressed conditions requires the plant to activate coping mechanisms at a level commensurate with the severity of the drought stress. The osmotic sensors and associated regulatory mechanisms that initiate drought- and salt-tolerance responses in plants are largely unknown. This research aimed to identify and characterize these initial sensory components.

  8. Abscisic Acid Participates in the Control of Cell Cycle Initiation Through Heme Homeostasis in the Unicellular Red Alga Cyanidioschyzon merolae.

    Kobayashi, Yuki; Ando, Hiroyuki; Hanaoka, Mitsumasa; Tanaka, Kan

    2016-05-01

    ABA is a phytohormone that is synthesized in response to abiotic stresses and other environmental changes, inducing various physiological responses. While ABA has been found in unicellular photosynthetic organisms, such as cyanobacteria and eukaryotic algae, its function in these organisms is poorly understood. Here, we found that ABA accumulated in the unicellular red alga Cyanidioschyzon merolae under conditions of salt stress and that the cell cycle G1/S transition was inhibited when ABA was added to the culture medium. A gene encoding heme-scavenging tryptophan-rich sensory protein-related protein (CmTSPO; CMS231C) was positively regulated by ABA, as in Arabidopsis, and CmTSPO bound heme in vitro. The intracellular content of total heme was increased by addition of ABA, but unfettered heme decreased, presumably due to scavenging by CmTSPO. The inhibition of DNA replication by ABA was negated by addition of heme to the culture medium. Thus, we propose a regulatory role for ABA and heme in algal cell cycle initiation. Finally, we found that a C. merolae mutant that is defective in ABA production was more susceptible to salt stress, indicating the importance of ABA to stress resistance in red algae. PMID:27044672

  9. Elevated air movement enhances stomatal sensitivity to abscisic acid in leaves developed at high relative air humidity

    Carvalho, D.R.A.; Torre, S.; Kraniotis, D.; Almeida, D.P.F.; Heuvelink, E.; Carvalho, S.M.P.

    2015-01-01

    High relative air humidity (RH = 85%) during growth leads to stomata malfunctioning, resulting in water stress when plants are transferred to conditions of high evaporative demand. In this study, we hypothesized that an elevated air movement (MOV) 24 h per day, during the whole period of leaf develo

  10. Mesophyll conductance to CO2 transport estimated by two independent methods: effect of variable CO2 concentration and abscisic acid

    Vrábl, D.; Vašková, M.; Hronková, Marie; Flexas, J.; Šantrůček, Jiří

    2009-01-01

    Roč. 60, č. 8 (2009), s. 2315-2323. ISSN 0022-0957 R&D Projects: GA AV ČR(CZ) IAA601410505 Institutional research plan: CEZ:AV0Z50510513 Keywords : Carbon dioxide * mesophyll conductance * Helianthus annuus Subject RIV: ED - Physiology Impact factor: 4.271, year: 2009

  11. Water stress responses of tomato mutants impaired in hormone biosynthesis reveal abscisic acid, jasmonic acid and salicylic acid interactions

    Valeria eMuñoz

    2015-11-01

    Full Text Available To investigate the putative crosstalk between JA and ABA in Solanum lycopersicum plants in response to drought, suppressor of prosystemin-mediated responses2 (spr2, JA-deficient and flacca (flc, ABA-deficient mutants together with the naphthalene/salicylate hydroxylase (NahG transgenic (SA-deficient line were used. Hormone profiling and gene expression of key enzymes in ABA, JA and SA biosynthesis were analyzed during early stages of drought. ABA accumulation was comparable in spr2 and wild type (WT plants whereas expression of 9-cis-epoxycarotenoid dioxygenase 1 (NCED1 and NCED2 was different, implying a compensation mechanism between NCED genes and an organ-specific regulation of NCED1 expression. JA levels and 12-oxo-phytodienoic acid reductase 3 (OPR3 expression in flc plants suggest that ABA regulates the induction of the OPR3 gene in roots. By contrast, ABA treatment to flc plants leads to a reduction of JA and SA contents. Furthermore, different pattern of SA accumulation (and expression of isochorismate synthase and phenylalanine ammonia lyase 1 was observed between WT seedlings and mutants, suggesting that SA plays an important role on the early response of tomato plants to drought and also that JA and ABA modulate its biosynthesis. Finally, hormone profiling in spr2 and NahG plants indicate a crosstalk between JA and SA that could enhance tolerance of tomato to water stress.

  12. Water Stress Responses of Tomato Mutants Impaired in Hormone Biosynthesis Reveal Abscisic Acid, Jasmonic Acid and Salicylic Acid Interactions.

    Muñoz-Espinoza, Valeria A; López-Climent, María F; Casaretto, José A; Gómez-Cadenas, Aurelio

    2015-01-01

    To investigate the putative crosstalk between JA and ABA in Solanum lycopersicum plants in response to drought, suppressor of prosystemin-mediated responses2 (spr2, JA-deficient) and flacca (flc, ABA-deficient) mutants together with the naphthalene/salicylate hydroxylase (NahG) transgenic (SA-deficient) line were used. Hormone profiling and gene expression of key enzymes in ABA, JA and SA biosynthesis were analyzed during early stages of drought. ABA accumulation was comparable in spr2 and wild type (WT) plants whereas expression of 9-cis-epoxycarotenoid dioxygenase 1 (NCED1) and NCED2 was different, implying a compensation mechanism between NCED genes and an organ-specific regulation of NCED1 expression. JA levels and 12-oxo-phytodienoic acid reductase 3 (OPR3) expression in flc plants suggest that ABA regulates the induction of the OPR3 gene in roots. By contrast, ABA treatment to flc plants leads to a reduction of JA and SA contents. Furthermore, different pattern of SA accumulation (and expression of isochorismate synthase and phenylalanine ammonia lyase 1) was observed between WT seedlings and mutants, suggesting that SA plays an important role on the early response of tomato plants to drought and also that JA and ABA modulate its biosynthesis. Finally, hormone profiling in spr2 and NahG plants indicate a crosstalk between JA and SA that could enhance tolerance of tomato to water stress. PMID:26635826

  13. Effect of 2,4-D on content of abscisic and 3-indoleacetic acids in corn coleoptile segments

    The authors studied the influence of growth-stimulating (10-4 M), growth-inhibiting (3 x 10-3 M), lethal (7.5 x 10-3 M) concentrations of 2,4-D on content of ABA and IAA, as well as on entry and conversion of [1-14C]-2,4-D, in corn (Zea mays L.) coleoptile segments. Increase of ABA content was observed at 6 h after influence of a stimulating dose of 2,4-D, an inhibiting dose caused no changes of ABA content, and a lethal dose led to decline of its level. The content of IAA declined sharply at all of the studied 2,4-D concentrations. This effect was accompanied neither by intensification of IAA-oxidase activity nor by increase in the content of bound forms of IAA. Metabolism of 2,4-D was realized mainly via hydroxylation of the benzene ring with subsequent hydroxylation, as well as by means of glucose ester formation. These processes transpired most intensively in the case of a stimulating dose of 2,4-D and less intensively in the case of an inhibiting dose and especially in that of a lethal dose

  14. Perioxidases play important roles in abscisic acid (ABA)-simulating photosystem II (PSII) thermostabilty of apple tree rootstock leaves

    Brestic, M.; Shao, H. B.; Ferus, P.; Malbeck, Jiří

    2011-01-01

    Roč. 10, č. 71 (2011), s. 15891-15900. ISSN 1684-5315 Institutional research plan: CEZ:AV0Z50380511 Keywords : Photosystem II thermostability * antioxidant activity * phytohormones Subject RIV: EF - Botanics Impact factor: 0.573, year: 2010

  15. Meristem maintenance, auxin, jasmonic and abscisic acid pathways as a mechanism for phenotypic plasticity in Antirrhinum majus

    Julia Weiss; Raquel Alcantud-Rodriguez; Tugba Toksöz; Marcos Egea-Cortines

    2016-01-01

    Plants grow under climatic changing conditions that cause modifications in vegetative and reproductive development. The degree of changes in organ development i.e. its phenotypic plasticity seems to be determined by the organ identity and the type of environmental cue. We used intraspecific competition and found that Antirrhinum majus behaves as a decoupled species for lateral organ size and number. Crowding causes decreases in leaf size and increased leaf number whereas floral size is robust...

  16. Endogenous Abscisic Acid Promotes Hypocotyl Growth and Affects Endoreduplication during Dark-Induced Growth in Tomato (Solanum lycopersicum L.)

    Humplík, Jan; Bergougnoux, V.; Jandová, M.; Šimura, Jan; Pěnčík, Aleš; Tomanec, O.; Rolčík, Jakub; Novák, Ondřej; Fellner, Martin

    2015-01-01

    Roč. 10, č. 2 (2015). E-ISSN 1932-6203 R&D Projects: GA MŠk(CZ) LO1204 Institutional support: RVO:61389030 Keywords : DEPENDENT KINASE INHIBITOR * DEFICIENT MUTANT SITIENS * ARABIDOPSIS-THALIANA Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 3.234, year: 2014

  17. Long-term effects of abscisic acid (ABA) on the grape berry phenylpropanoid pathway: Gene expression and metabolite content.

    Villalobos-González, Luis; Peña-Neira, Alvaro; Ibáñez, Freddy; Pastenes, Claudio

    2016-08-01

    ABA has been proposed as the main signal triggering the onset of the ripening process in grapes, and modulating the secondary metabolism in grape berry skins. To determine the effect of ABA on secondary metabolism in berries, clusters of Carménère were sprayed with 0 μLL(-1) ABA; 50 μLL(-1) ABA and 100 μLL(-1) ABA during pre-véraison, and the gene expression of the transcription factors and enzymes of the phenylpropanoid pathway were assessed from véraison to 70 days after véraison (DAV). Additionally, flavonols, tannins and anthocyanins were assessed from véraison until harvest (110 DAV). ABA accelerated sugar and anthocyanin accumulation at véraison. The grape transcript abundance of VvDFR, VvANS, VvUFGT and VvMybA1, all peaking around véraison mimicked the concentration of ABA throughout the season. The highest anthocyanin concentration occurred 35 DAV for all treatments, but higher pigment concentrations were observed in ABA-treated berries at véraison and from 60 to 70 DAV to harvest. VvPAL was also increased by treatment at the higher concentration of ABA from véraison to 40 DAV. Regarding flavanol synthesis, VvLAR2 and VvMyb4A decreased from véraison until 40 DAV and then increased again until 70 DAV. Compared to the control, both ABA treatments resulted in a less-than-proportional reduction of the expression of both genes compared to the control and, after 40 DAV, in a more-than-proportional increase compared to the control, suggesting a long-term effect of the pre-véraison ABA spray on the berries. A concomitant increase in flavanols was observed in berries after 40 DAV, and this occurred at a higher extent in berries treated with the highest ABA concentration. PMID:27116369

  18. Regulation of erucic acid accumulation in oilseed rape (Brassica napus L.). Effects of temperature and abscisic acid.

    Wilmer, J.A.

    1997-01-01

    Vegetable oils are an important commodity world-wide with an annual production of about 70 million tonnes. Oilseed rape is one of the four major crops, providing about 10% of the total production. Quality of vegetable oils is determined by the fatty acid composition of the triacylglycerols (TAG) that constitute such oils. These fatty acids comprise a range of chain lengths and desaturated and oxidised residues. A small group of fatty acids dominates the edible oils which are the predominant p...

  19. Regulation of erucic acid accumulation in oilseed rape (Brassica napus L.). Effects of temperature and abscisic acid.

    Wilmer, J.A.

    1997-01-01

    Vegetable oils are an important commodity world-wide with an annual production of about 70 million tonnes. Oilseed rape is one of the four major crops, providing about 10% of the total production. Quality of vegetable oils is determined by the fatty acid composition of the triacylglycerols (TAG) tha

  20. Effects of abscisic acid or benzyladenine on pigment contents, chlorophyll fluorescence, and chloroplast ultrastructure during water stress and after rehydration

    Haisel, Daniel; Pospíšilová, Jana; Synková, Helena; Schnablová, Renáta; Baťková, Petra

    2006-01-01

    Roč. 44, č. 4 (2006), s. 606-614. ISSN 0300-3604 R&D Projects: GA ČR GA522/04/0549 Institutional research plan: CEZ:AV0Z50380511 Source of funding: V - iné verejné zdroje Keywords : Beta vulgaris * Nicotiana tabacum * Phaseolus vulgaris * starch content * Zea mays Subject RIV: ED - Physiology Impact factor: 0.782, year: 2006

  1. Highly Sprouting-Tolerant Wheat Grain Exhibits Extreme Dormancy and Cold Imbibition-Resistant Accumulation of Abscisic Acid.

    Kashiwakura, Yu-Ichi; Kobayashi, Daisuke; Jikumaru, Yusuke; Takebayashi, Yumiko; Nambara, Eiji; Seo, Mitsunori; Kamiya, Yuji; Kushiro, Tetsuo; Kawakami, Naoto

    2016-04-01

    Pre-harvest sprouting (PHS) of wheat (Triticum aestivumL.) grains induces hydrolyzing enzymes such as α-amylase, which considerably decreases wheat product quality. PHS occurs when cool and wet weather conditions before harvest break dormancy and induce grain germination. In this study, we used PHS-tolerant varieties, Gifu-komugi (Gifu) and OS38, to characterize the mechanisms of both dormancy breakage and dormancy maintenance at low temperatures. Physiologically mature Gifu grains exhibited dormancy after imbibition at 20°C, but germinated at 15°C. In contrast, OS38 grains remained dormant even at temperatures as low as 5°C. Embryo half-grains cut out from the dormant Gifu grains germinated by imbibition at 20°C, similar to conventional varieties worldwide. However, OS38 embryo half-grains were still dormant. Hormonome and pharmacological analyses suggested that ABA and gibberellin metabolism are important for temperature-dependent dormancy maintenance and breakage. Imbibition at 15°C decreased ABA levels but increased gibberellin levels in embryos of freshly harvested Gifu grains. Additionally, low temperatures induced expression of the ABA catabolism genes,TaABA8'OH1andTaABA8'OH2, and the gibberellin biosynthesis gene,TaGA3ox2, in the embryos. However, in embryos of freshly harvested OS38 grains, ABA levels were increased while gibberellin levels were suppressed at 15°C. In these dormant embryos, low temperatures induced theTaNCEDABA biosynthesis genes, but suppressedTaABA8'OH2andTaGA3ox2.These results show that the regulatory mechanism influencing the expression of ABA and gibberellin metabolism genes may be critical for dormancy maintenance and breakage at low temperatures. Our findings should help improve PHS-resistant wheat breeding programs. PMID:26971301

  2. Long-term and short-term effects of abscisic acid on plantlet acclimatization to ex vitro conditions

    Pospíšilová, Jana; Haisel, Daniel; Synková, Helena; Baťková, Petra

    Ciego de Avila : University of Ciego, 2009, s. 1-6. [Congreso International de Biotecnología Vegetal. Congreso International de Biotecnología Vegetal (ES), 05.10.2009-07.10.2009] R&D Projects: GA ČR GA522/07/0227 Institutional research plan: CEZ:AV0Z50380511 Keywords : carotenoids * chlorophyll contents * chlorophyll fluorescence Subject RIV: ED - Physiology

  3. Improvement of ex vitro transfer of tobacco plantlets by addition of abscisic acid to the last subculture

    Pospíšilová, Jana; Haisel, Daniel; Synková, Helena; Baťková, Petra

    2009-01-01

    Roč. 53, č. 4 (2009), s. 617-624. ISSN 0006-3134 R&D Projects: GA ČR GA522/07/0227 Institutional research plan: CEZ:AV0Z50380511 Keywords : carotenoids * chlorophyll contents * chlorophyll fluorescence Subject RIV: ED - Physiology Impact factor: 1.656, year: 2009

  4. Riboflavin-induced Priming for Pathogen Defense in Arabidopsis thaliana

    Shujian Zhang; Xue Yang; Maowu Sun; Feng Sun; Sheng Deng; Hansong Dong

    2009-01-01

    Riboflavin (vitamin B2) participates in a variety of redox processes that affect plant defense responses. Previously we have shown that riboflavin induces pathogen resistance in the absence of hypersensitive cell death (HCD) in plants. Herein, we report that riboflavin induces priming of defense responses in Arabidopsis thaliana toward infection by virulent Pseudomonas syringae pv. Tomato DC3000 (Pst). Induced resistance was mechanistically connected with the expression of defense response genes and cellular defense events, including H2O2 burst, HCD, and callose deposition in the plant. Riboflavin treatment and inoculation of plants with Pst were neither active but both synergized to induce defense responses. The priming process needed NPR1 (essential regulator of systemic acquired resistance) and maintenance of H2O2 burst but was independent of salicylic acid, jasmonic acid, ethylene, and abscisic acid. Our results suggest that the role of riboflavin in priming defenses is subject to a signaling process distinct from the known pathways of hormone signal transduction.

  5. Wounding in the plant tissue: the defense of a dangerous passage

    Daniel Valentin Savatin

    2014-09-01

    Full Text Available Plants are continuously exposed to agents such as herbivores and environmental mechanical stresses that cause wounding and open the way to the invasion by microbial pathogens. Wounding provides nutrients to pathogens and facilitates their entry into the tissue and subsequent infection. Plants have evolved constitutive and induced defense mechanisms to properly respond to wounding and prevent infection. The constitutive defenses are represented by physical barriers, i.e. the presence of cuticle or lignin, or by metabolites that act as toxins or deterrents for herbivores. Plants are also able to sense the injured tissue as an altered self and induce responses similar to those activated by pathogen infection. Endogenous molecules released from wounded tissue may act as Damage-Associated Molecular Patterns (DAMPs that activate the plant innate immunity. Wound-induced responses are both rapid, such as the oxidative burst and the expression of defense-related genes, and late, such as the callose deposition, the accumulation of proteinase inhibitors and of hydrolytic enzymes (i.e. chitinases and gluganases. Typical examples of DAMPs involved in the response to wounding are the peptide systemin and the oligogalacturonides, which are oligosaccharides released from the pectic component of the cell wall. Responses to wounding take place both at the site of damage (local response and systemically (systemic response and are mediated by hormones such as jasmonic acid, ethylene, salicylic acid and abscisic acid.

  6. Physiological and molecular analysis of the interaction between aluminium toxicity and drought stress in common bean (Phaseolus vulgaris).

    Yang, Zhong-Bao; Eticha, Dejene; Albacete, Alfonso; Rao, Idupulapati Madhusudana; Roitsch, Thomas; Horst, Walter Johannes

    2012-05-01

    Aluminium (Al) toxicity and drought are two major factors limiting common bean (Phaseolus vulgaris) production in the tropics. Short-term effects of Al toxicity and drought stress on root growth in acid, Al-toxic soil were studied, with special emphasis on Al-drought interaction in the root apex. Root elongation was inhibited by both Al and drought. Combined stresses resulted in a more severe inhibition of root elongation than either stress alone. This result was different from the alleviation of Al toxicity by osmotic stress (-0.60 MPa polyethylene glycol) in hydroponics. However, drought reduced the impact of Al on the root tip, as indicated by the reduction of Al-induced callose formation and MATE expression. Combined Al and drought stress enhanced up-regulation of ACCO expression and synthesis of zeatin riboside, reduced drought-enhanced abscisic acid (ABA) concentration, and expression of NCED involved in ABA biosynthesis and the transcription factors bZIP and MYB, thus affecting the regulation of ABA-dependent genes (SUS, PvLEA18, KS-DHN, and LTP) in root tips. The results provide circumstantial evidence that in soil, drought alleviates Al injury, but Al renders the root apex more drought-sensitive, particularly by impacting the gene regulatory network involved in ABA signal transduction and cross-talk with other phytohormones necessary for maintaining root growth under drought. PMID:22371077

  7. Manipulation of the Xanthophyll Cycle Increases Plant Susceptibility to Sclerotinia sclerotiorum.

    Jun Zhou

    2015-05-01

    Full Text Available The xanthophyll cycle is involved in dissipating excess light energy to protect the photosynthetic apparatus in a process commonly assessed from non-photochemical quenching (NPQ of chlorophyll fluorescence. Here, it is shown that the xanthophyll cycle is modulated by the necrotrophic pathogen Sclerotinia sclerotiorum at the early stage of infection. Incubation of Sclerotinia led to a localized increase in NPQ even at low light intensity. Further studies showed that this abnormal change in NPQ was closely correlated with a decreased pH caused by Sclerotinia-secreted oxalate, which might decrease the ATP synthase activity and lead to a deepening of thylakoid lumen acidification under continuous illumination. Furthermore, suppression (with dithiothreitol or a defect (in the npq1-2 mutant of violaxanthin de-epoxidase (VDE abolished the Sclerotinia-induced NPQ increase. HPLC analysis showed that the Sclerotinia-inoculated tissue accumulated substantial quantities of zeaxanthin at the expense of violaxanthin, with a corresponding decrease in neoxanthin content. Immunoassays revealed that the decrease in these xanthophyll precursors reduced de novo abscisic acid (ABA biosynthesis and apparently weakened tissue defense responses, including ROS induction and callose deposition, resulting in enhanced plant susceptibility to Sclerotinia. We thus propose that Sclerotinia antagonizes ABA biosynthesis to suppress host defense by manipulating the xanthophyll cycle in early pathogenesis. These findings provide a model of how photoprotective metabolites integrate into the defense responses, and expand the current knowledge of early plant-Sclerotinia interactions at infection sites.

  8. Transglutaminase-induced or citric acid-mediated cross-linking of whey proteins to tune the characteristics of subsequently desolvated sub-micron and nano-scaled particles.

    Bagheri, Leila; Yarmand, Mohammadsaeed; Madadlou, Ashkan; Mousavi, Mohammad E

    2014-01-01

    Whey proteins were inter-connected either by the enzyme transglutaminase or citric acid and then desolvated with ethanol to generate particles. Both samples comprised of sub-micron (>300 nm) and nano-scaled (~100 nm) particles based on the hydrodynamic size measurements. Enzyme-induced cross-linking of proteins yielded more monodisperse particles and decreased the mean size of the major (nano-scaled) fraction of particles. Scanning electron microscopy images revealed a spherical morphology for all samples with mean sizes of Atomic force microscopy indicated a lower height for the particles from enzymatically cross-linked proteins. The mediating role of citric acid in bridging the proteins was confirmed by Fourier transform infrared spectroscopy. Differential scanning calorimetry indicated that pre-heating of protein solution before cross-linking and desolvation denatured the proteins entirely. In vitro degradation of whey protein particles in a simulated gastric fluid demonstrated that cross-linking of whey proteins before desolvation stage enhanced significantly the digestion stability of particles. PMID:24766206

  9. Retinoic acid-mediated repression of human papillomavirus 18 transcription and different ligand regulation of the retinoic acid receptor beta gene in non-tumorigenic and tumorigenic HeLa hybrid cells.

    Bartsch, D; Boye, B; Baust, C; zur Hausen, H; Schwarz, E

    1992-01-01

    Human papillomavirus type 18 (HPV18) belongs to the group of genital papillomaviruses involved in the development of cervical carcinomas. Since retinoic acid (RA) is a key regulator of epithelial cell differentiation and a growth inhibitor in vitro of HPV18-positive HeLa cervical carcinoma cells, we have used HeLa and HeLa hybrid cells in order to analyse the effects of RA on expression of the HPV18 E6 and E7 oncogenes and of the cellular RA receptor genes RAR-beta and -gamma. We show here that RA down-regulates HPV18 mRNA levels apparently due to transcriptional repression. Transient cotransfection assays indicated that RARs negatively regulate the HPV18 upstream regulatory region and that the central enhancer can confer RA-dependent repression on a heterologous promoter. RA treatment resulted in induction of RAR-beta mRNA levels in non-tumorigenic HeLa hybrid cells, but not in tumorigenic hybrid segregants nor in HeLa cells. No alterations of the RAR-beta gene or of the HeLa RAR-beta promoter could be revealed by Southern and DNA sequence analysis, respectively. As determined by transient transfection assays, however, the RAR-beta control region was activated by RA more strongly in non-tumorigenic hybrid cells than in HeLa cells, thus indicating differences in trans-acting regulatory factors. Our data suggest that the RARs are potential negative regulators of HPV18 E6 and E7 gene expression, and that dysregulation of the RAR-beta gene either causatively contributes to or is an indicator of tumorigenicity in HeLa and HeLa hybrid cells. Images PMID:1318198

  10. Tailored-CuO-nanowire decorated with folic acid mediated coupling of the mitochondrial-ROS generation and miR425-PTEN axis in furnishing potent anti-cancer activity in human triple negative breast carcinoma cells.

    Ahir, Manisha; Bhattacharya, Saurav; Karmakar, Soumendu; Mukhopadhyay, Ayan; Mukherjee, Sudeshna; Ghosh, Swatilekha; Chattopadhyay, Sreya; Patra, Prasun; Adhikary, Arghya

    2016-01-01

    Metal oxide nanoparticles are the forthcoming anti-tumor therapeutics and provide a versatile platform in the development of therapeutic approaches for drug-resistant cancers such as triple negative breast cancer (TNBC). Copper oxide nanoparticles have been characterized as anti-cancer agents but its toxicity has been a matter of concern. Herein, we have developed a targeted CuO Nanowire fabricated with Folic acid (CuO-Nw-FA) that enables enhanced cellular uptake in TNBC cells without imparting significant toxicity in normal cellular system. In the present study, we enumerated that CuO-Nw-FA caused mitochondrial-dependent apoptosis in MDAMB-231 cells. Furthermore, CuO-Nw-FA mediated cytosolic retardation of NF-κB favoured inactivation of miR-425 and henceforth activated PTEN to induce apoptosis in TNBC cells. Simultaneously, CuO-Nw-FA also restricted the in-vitro cell migration through the miR-425/PTEN axis via pFAK. Studies extended to ex-ovo and in-vivo mice models further validated the efficacy of CuO-Nw-FA. Additionally, the accumulations of nanoparticles in tumor as well as different organs in mice were examined by in-vivo biodistribution and ex-vivo optical imaging studies. Thus our results cumulatively propose that CuO-Nw-FA cross-talks two distinct signalling pathways to induce apoptosis and retard migration in TNBC cells and raises the possibility for the use of CuO-Nw-FA as a potent anti-tumor agent. PMID:26520043

  11. Tautomerism in quinoxalines derived from the 1,4-naphthoquinone nucleus: acid mediated synthesis, X-ray molecular structure of 5-chlorobenzo[f]quinoxalin-6-ol and density functional theory calculations

    Gomez, Javier A.G.; Lage, Mateus R.; Carneiro, Jose Walkimar de M.; Resende, Jackson A.L.C.; Vargas, Maria D., E-mail: mdvargas@vm.uff.br, E-mail: walk@vm.uff.br [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil). Instituto de Quimica

    2013-02-15

    The reaction of tert-butyl 2-(3-chloro-1,4-dioxo-1,4-dihydronaphthalen-2-ylamino) ethylcarbamate with CF{sub 3}COOH/CH{sub 2}Cl{sub 2} yields 5-chloro-3,4-dihydrobenzo[f]quinoxalin-6(2H)-one which undergoes acid-promoted dehydrogenation in the presence of water to give novel 5-chlorobenzo[f]quinoxalin-6-ol. The molecular structure of 5-chlorobenzo[f]quinoxalin-6-ol in the solid state, determined by an X-ray diffraction (XRD) study, and the solution data confirm that it exists as the enol-imine tautomer, both in the solid state and in solution, differently from 5-chloro-3,4-dihydrobenzo[f]quinoxalin-6(2H)-one, which exhibits the keto-amine arrangement. Density functional theory (DFT) calculations confirmed the preference of 5-chlorobenzo[f]quinoxalin-6-ol and of the derivatives containing H and CH{sub 3} groups in place of the Cl atom for the enol-imine tautomer. It is suggested that the enol-imine structure is preferred for 5-chlorobenzo[f]quinoxalin-6-ol as a consequence of the higher aromatic character of this structure in comparison with the keto-amine form. DFT calculations carried out on the two tautomers of the benzo[a]phenazin-5(7H)-ones analogous to the benzo[f]quinoxalin-6(4H)-ones showed that the relative stabilities are dominated by solvation effects in the first case and the degree of aromaticity, in the latter. (author)

  12. TOPOISOMERASE 6B is involved in chromatin remodelling associated with control of carbon partitioning into secondary metabolites and cell walls, and epidermal morphogenesis in Arabidopsis.

    Mittal, Amandeep; Balasubramanian, Rajagopal; Cao, Jin; Singh, Prabhjeet; Subramanian, Senthil; Hicks, Glenn; Nothnagel, Eugene A; Abidi, Noureddine; Janda, Jaroslav; Galbraith, David W; Rock, Christopher D

    2014-08-01

    Plant growth is continuous and modular, a combination that allows morphogenesis by cell division and elongation and serves to facilitate adaptation to changing environments. The pleiotropic phenotypes of the harlequin (hlq) mutant, isolated on the basis of ectopic expression of the abscisic acid (ABA)- and auxin-inducible proDc3:GUS reporter gene, were previously characterized. Mutants are skotomorphogenic, have deformed and collapsed epidermal cells which accumulate callose and starch, cell walls abundant in pectins and cell wall proteins, and abnormal and reduced root hairs and leaf trichomes. hlq and two additional alleles that vary in their phenotypic severity of starch accumulation in the light and dark have been isolated, and it is shown that they are alleles of bin3/hyp6/rhl3/Topoisomerase6B. Mutants and inhibitors affecting the cell wall phenocopy several of the traits displayed in hlq. A microarray analysis was performed, and coordinated expression of physically adjacent pairs/sets of genes was observed in hlq, suggesting a direct effect on chromatin. Histones, WRKY and IAA/AUX transcription factors, aquaporins, and components of ubiquitin-E3-ligase-mediated proteolysis, and ABA or biotic stress response markers as well as proteins involved in cellular processes affecting carbon partitioning into secondary metabolites were also identified. A comparative analysis was performed of the hlq transcriptome with other previously published TopoVI mutant transcriptomes, namely bin3, bin5, and caa39 mutants, and limited concordance between data sets was found, suggesting indirect or genotype-specific effects. The results shed light on the molecular mechanisms underlying the det/cop/fus-like pleiotropic phenotypes of hlq and support a broader role for TopoVI regulation of chromatin remodelling to mediate development in response to environmental and hormonal signals. PMID:24821950

  13. Activation of Shikimate, Phenylpropanoid, Oxylipins, and Auxin Pathways in Pectobacterium carotovorum Elicitors-Treated Moss.

    Alvarez, Alfonso; Montesano, Marcos; Schmelz, Eric; Ponce de León, Inés

    2016-01-01

    Plants have developed complex defense mechanisms to cope with microbial pathogens. Pathogen-associated molecular patterns (PAMPs) and damage-associated molecular patterns (DAMPs) are perceived by pattern recognition receptors (PRRs), leading to the activation of defense. While substantial progress has been made in understanding the activation of plant defense by PAMPs and DAMPs recognition in tracheophytes, far less information exists on related processes in early divergent plants like mosses. The aim of this study was to identify genes that were induced in P. patens in response to elicitors of Pectobacterium carotovorum subsp. carotovorum, using a cDNA suppression subtractive hybridization (SSH) method. A total of 239 unigenes were identified, including genes involved in defense responses related to the shikimate, phenylpropanoid, and oxylipin pathways. The expression levels of selected genes related to these pathways were analyzed using quantitative RT-PCR, confirming their rapid induction by P.c. carotovorum derived elicitors. In addition, P. patens induced cell wall reinforcement after elicitor treatment by incorporation of phenolic compounds, callose deposition, and elevated expression of Dirigent-like encoding genes. Small molecule defense markers and phytohormones such as cinnamic acid, 12-oxo-phytodienoic acid, and auxin levels all increased in elicitor-treated moss tissues. In contrast, salicylic acid levels decreased while abscisic acid levels remained unchanged. P. patens reporter lines harboring an auxin-inducible promoter fused to β-glucuronidase revealed GUS activity in protonemal and gametophores tissues treated with elicitors of P.c. carotovorum, consistent with a localized activation of auxin signaling. These results indicate that P. patens activates the shikimate, phenylpropanoid, oxylipins, and auxin pathways upon treatment with P.c. carotovorum derived elicitors. PMID:27047509

  14. A myo-inositol-1-phosphate synthase gene, IbMIPS1, enhances salt and drought tolerance and stem nematode resistance in transgenic sweet potato.

    Zhai, Hong; Wang, Feibing; Si, Zengzhi; Huo, Jinxi; Xing, Lei; An, Yanyan; He, Shaozhen; Liu, Qingchang

    2016-02-01

    Myo-inositol-1-phosphate synthase (MIPS) is a key rate limiting enzyme in myo-inositol biosynthesis. The MIPS gene has been shown to improve tolerance to abiotic stresses in several plant species. However, its role in resistance to biotic stresses has not been reported. In this study, we found that expression of the sweet potato IbMIPS1 gene was induced by NaCl, polyethylene glycol (PEG), abscisic acid (ABA) and stem nematodes. Its overexpression significantly enhanced stem nematode resistance as well as salt and drought tolerance in transgenic sweet potato under field conditions. Transcriptome and real-time quantitative PCR analyses showed that overexpression of IbMIPS1 up-regulated the genes involved in inositol biosynthesis, phosphatidylinositol (PI) and ABA signalling pathways, stress responses, photosynthesis and ROS-scavenging system under salt, drought and stem nematode stresses. Inositol, inositol-1,4,5-trisphosphate (IP3 ), phosphatidic acid (PA), Ca(2+) , ABA, K(+) , proline and trehalose content was significantly increased, whereas malonaldehyde (MDA), Na(+) and H2 O2 content was significantly decreased in the transgenic plants under salt and drought stresses. After stem nematode infection, the significant increase of inositol, IP3 , PA, Ca(2+) , ABA, callose and lignin content and significant reduction of MDA content were found, and a rapid increase of H2 O2 levels was observed, peaked at 1 to 2 days and thereafter declined in the transgenic plants. This study indicates that the IbMIPS1 gene has the potential to be used to improve the resistance to biotic and abiotic stresses in plants. PMID:26011089

  15. Multiple Xanthomonas euvesicatoria Type III Effectors Inhibit flg22-Triggered Immunity.

    Popov, Georgy; Fraiture, Malou; Brunner, Frederic; Sessa, Guido

    2016-08-01

    Xanthomonas euvesicatoria is the causal agent of bacterial spot disease in pepper and tomato. X. euvesicatoria bacteria interfere with plant cellular processes by injecting effector proteins into host cells through the type III secretion (T3S) system. About 35 T3S effectors have been identified in X. euvesicatoria 85-10, and a few of them were implicated in suppression of pattern-triggered immunity (PTI). We used an Arabidopsis thaliana pathogen-free protoplast-based assay to identify X. euvesicatoria 85-10 effectors that interfere with PTI signaling induced by the bacterial peptide flg22. Of 33 tested effectors, 17 inhibited activation of a PTI-inducible promoter. Among them, nine effectors also interfered with activation of an abscisic acid-inducible promoter. However, effectors that inhibited flg22-induced signaling did not affect phosphorylation of mitogen-activated protein (MAP) kinases acting downstream of flg22 perception. Further investigation of selected effectors revealed that XopAJ, XopE2, and XopF2 inhibited activation of a PTI-inducible promoter by the bacterial peptide elf18 in Arabidopsis protoplasts and by flg22 in tomato protoplasts. The effectors XopF2, XopE2, XopAP, XopAE, XopH, and XopAJ inhibited flg22-induced callose deposition in planta and enhanced disease symptoms caused by attenuated Pseudomonas syringae bacteria. Finally, selected effectors were found to localize to various plant subcellular compartments. These results indicate that X. euvesicatoria bacteria utilize multiple T3S effectors to suppress flg22-induced signaling acting downstream or in parallel to MAP kinase cascades and suggest they act through different molecular mechanisms. PMID:27529660

  16. OsRACK1 Is Involved in Abscisic Acid- and H2O2-Mediated Signaling to Regulate Seed Germination in Rice (Oryza sativa, L.)

    Zhang, Dongping; Chen, Li; Li, Dahong; Lv, Bing; Chen, Yun; Chen, Jingui; XuejiaoYan,; Liang, Jiansheng

    2014-01-01

    The receptor for activated C kinase 1 (RACK1) is one member of the most important WD repeat–containing family of proteins found in all eukaryotes and is involved in multiple signaling pathways. However, compared with the progress in the area of mammalian RACK1, our understanding of the functions and molecular mechanisms of RACK1 in the regulation of plant growth and development is still in its infancy. In the present study, we investigated the roles of rice RACK1A gene (OsRACK1A) in controlli...

  17. OsRACK1 is involved in abscisic acid- and H2O2-mediated signaling to regulate seed germination in rice (Oryza sativa, L..

    Dongping Zhang

    Full Text Available The receptor for activated C kinase 1 (RACK1 is one member of the most important WD repeat-containing family of proteins found in all eukaryotes and is involved in multiple signaling pathways. However, compared with the progress in the area of mammalian RACK1, our understanding of the functions and molecular mechanisms of RACK1 in the regulation of plant growth and development is still in its infancy. In the present study, we investigated the roles of rice RACK1A gene (OsRACK1A in controlling seed germination and its molecular mechanisms by generating a series of transgenic rice lines, of which OsRACK1A was either over-expressed or under-expressed. Our results showed that OsRACK1A positively regulated seed germination and negatively regulated the responses of seed germination to both exogenous ABA and H2O2. Inhibition of ABA biosynthesis had no enhancing effect on germination, whereas inhibition of ABA catabolism significantly suppressed germination. ABA inhibition on seed germination was almost fully recovered by exogenous H2O2 treatment. Quantitative analyses showed that endogenous ABA levels were significantly higher and H2O2 levels significantly lower in OsRACK1A-down regulated transgenic lines as compared with those in wildtype or OsRACK1A-up regulated lines. Quantitative real-time PCR analyses showed that the transcript levels of OsRbohs and amylase genes, RAmy1A and RAmy3D, were significantly lower in OsRACK1A-down regulated transgenic lines. It is concluded that OsRACK1A positively regulates seed germination by controlling endogenous levels of ABA and H2O2 and their interaction.

  18. The role of abscisic acid in the defence response of tomato (Solanum lycopersicum) to the necrotrophic pathogens Botrytis cinerea and Erwinia chrysanthemi

    Asselbergh, B.

    2007-01-01

    In order to cope with the constant threat of a wide range of potentially harmful micro-organisms, plants have developed an impressive constitutive and inducible defensive machinery of enormous complexity to combat pathogen invasion. Plant hormones are not only important for controlling plant development, but are also essential to regulate plant responses to the environment. The plant hormones salicylic acid (SA), jasmonate (JA) and ethylene (ET) are classically associated with plant pathogen ...

  19. Phytohormone Involvement in the Ustilago maydis- Zea mays Pathosystem: Relationships between Abscisic Acid and Cytokinin Levels and Strain Virulence in Infected Cob Tissue.

    Erin N Morrison

    Full Text Available Ustilago maydis is the causative agent of common smut of corn. Early studies noted its ability to synthesize phytohormones and, more recently these growth promoting substances were confirmed as cytokinins (CKs. Cytokinins comprise a group of phytohormones commonly associated with actively dividing tissues. Lab analyses identified variation in virulence between U. maydis dikaryon and solopathogen infections of corn cob tissue. Samples from infected cob tissue were taken at sequential time points post infection and biochemical profiling was performed using high performance liquid chromatography-electrospray ionization tandem mass spectrometry (HPLC-ESI MS/MS. This hormone profiling revealed that there were altered levels of ABA and major CKs, with a marked reduction in CK glucosides, increases in methylthiol CKs and a particularly dramatic increase in cisZ CK forms, in U. maydis infected tissue. These changes were more pronounced in the more virulent dikaryon relative to the solopathogenic strain suggesting a role for cytokinins in moderating virulence during biotrophic infection. These findings highlight the fact that U. maydis does not simply mimic a fertilized seed but instead reprograms the host tissue. Results underscore the suitability of the Ustilago maydis- Zea mays model as a basis for investigating the control of phytohormone dynamics during biotrophic infection of plants.

  20. Phytohormone Involvement in the Ustilago maydis– Zea mays Pathosystem: Relationships between Abscisic Acid and Cytokinin Levels and Strain Virulence in Infected Cob Tissue

    Morrison, Erin N.; Emery, R. J. Neil; Saville, Barry J.

    2015-01-01

    Ustilago maydis is the causative agent of common smut of corn. Early studies noted its ability to synthesize phytohormones and, more recently these growth promoting substances were confirmed as cytokinins (CKs). Cytokinins comprise a group of phytohormones commonly associated with actively dividing tissues. Lab analyses identified variation in virulence between U. maydis dikaryon and solopathogen infections of corn cob tissue. Samples from infected cob tissue were taken at sequential time poi...

  1. Changes in water status and proline and abscisic acid concentrations in developing somatic embryos of pedunculate oak (Quercus robur) during maturation and germination

    Prewein, Ch.; Vágner, Martin; Wilhelm, E.

    2004-01-01

    Roč. 24, č. 11 (2004), s. 1251-1257. ISSN 0829-318X R&D Projects: GA MŠk OC 843.50 Institutional research plan: CEZ:AV0Z5038910 Keywords : Fagaceae * forest tree * hardwood Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.462, year: 2004

  2. Association Between Seed Dormancy and Pericarp Color Is Controlled by a Pleiotropic Gene That Regulates Abscisic Acid and Flavonoid Synthesis in Weedy Red Rice

    Gu, Xing-You; Foley, Michael E.; Horvath, David P.; Anderson, James V.; Feng, Jiuhuan; Zhang, Lihua; Mowry, Chase R.; Ye, Heng; Suttle, Jeffrey C; Kadowaki, Koh-ichi; Chen, Zongxiang

    2011-01-01

    Seed dormancy has been associated with red grain color in cereal crops for a century. The association was linked to qSD7-1/qPC7, a cluster of quantitative trait loci for seed dormancy/pericarp color in weedy red rice. This research delimited qSD7-1/qPC7 to the Os07g11020 or Rc locus encoding a basic helix-loop-helix family transcription factor by intragenic recombinants and provided unambiguous evidence that the association arises from pleiotropy. The pleiotropic gene expressed in early devel...

  3. OsRACK1 Is Involved in Abscisic Acid- and H2O2-Mediated Signaling to Regulate Seed Germination in Rice (Oryza sativa, L.)

    Dongping Zhang; Li Chen; Dahong Li; Bing Lv; Yun Chen; Jingui Chen; XuejiaoYan; Jiansheng Liang

    2014-01-01

    The receptor for activated C kinase 1 (RACK1) is one member of the most important WD repeat-containing family of proteins found in all eukaryotes and is involved in multiple signaling pathways. However, compared with the progress in the area of mammalian RACK1, our understanding of the functions and molecular mechanisms of RACK1 in the regulation of plant growth and development is still in its infancy. In the present study, we investigated the roles of rice RACK1A gene (OsRACK1A) in controlli...

  4. A transcript profiling approach reveals an abscisic acid specific glycosyltransferase (UGT73C14) induced in developing fiber of Ligon lintless-2 mutant of cotton (Gossypium hirsutum L.)

    Ligon lintless-2, a monogenic dominant cotton (Gossypium hirsutum L.) fiber mutation, causing extreme reduction in lint fiber length with no pleiotropic effects on vegetative growth, represents an excellent model system to study fiber elongation. A UDP-glycosyltransferase that was highly expressed i...

  5. Tolerance of citrus plants to the combination of high temperatures and drought is associated to the increase in transpiration modulated by a reduction in abscisic acid levels

    Zandalinas, Sara I.; Rivero, Rosa M.; Martínez, Vicente; Gómez-Cadenas, Aurelio; Arbona, Vicent

    2016-01-01

    Background In natural environments, several adverse environmental conditions occur simultaneously constituting a unique stress factor. In this work, physiological parameters and the hormonal regulation of Carrizo citrange and Cleopatra mandarin, two citrus genotypes, in response to the combined action of high temperatures and water deprivation were studied. The objective was to characterize particular responses to the stress combination. Results Experiments indicated that Carrizo citrange is ...

  6. Dynamic changes of canopy-scale mesophyll conductance to CO(2) diffusion of sunflower as affected by CO(2) concentration and abscisic acid

    Schaufele, R.; Šantrůček, Jiří; Schnyder, H.

    2011-01-01

    Roč. 34, č. 1 (2011), s. 127-136. ISSN 0140-7791 R&D Projects: GA ČR GA206/08/0787 Institutional research plan: CEZ:AV0Z50510513 Keywords : carbon isotope discrimination * water - stress * in-vivo Subject RIV: EF - Botanics Impact factor: 5.215, year: 2011

  7. Spatio-temporal appearance of α-amylase and limit dextrinase in barley aleurone layer in response to gibberellic acid, abscisic acid and salicylic acid

    Shahpiri, Azar; Talaei, Nasim; Finnie, Christine

    2015-01-01

    Release of LD was found to differ from that of amylase and was suggested to depend on programmed cell death (PCD). Despite detection of intracellular amylase in untreated aleurone layers or aleurone layers treated with ABA or SA, α-amylase was not released from these samples. Nevertheless, the re...

  8. Cloning and characterization of a novel abscisic acid (aba)-induced hva22-like protein from triticum turgidum spp. dicoccoides in response to drought stress

    Doğan, Esen; Dogan, Esen

    2010-01-01

    An HVA22-like protein was found to be differentially expressed in root tissue of wild emmer wheat (Triticum turgidum ssp. dicoccoides), under prolonged drought stress conditions. In this study we were able to clone and characterize the open reading frame of HVA22-like protein from root tissue of wild emmer wheat accession number TR39477, which was previously shown to be a drought-tolerant genotype. Sequence analysis indicated that HVA22-like protein product was a membrane protein and had four...

  9. Protein (Viridiplantae): 356525683 [PGDBj - Ortholog DB

    Full Text Available YQLLFRLIVGSIFLTFLAIFIILIAVAKMTIKDIIVCILAVMPTGWGILLIAQACKPLIKKTWFWGSVRALARGYEVIMGLLLFTPVAFLAWFPFVSEFQTRMLFNQAFSRGLQISRILGGQSNERSSNHKE ... ...LQKIFPDEWKNFVQRFDNKSEEKLRVENEEELRLWASYRGQTLTKTVRGMMYIRQALELQAFLDMAKDEELMKGYKAAELESKESTTGERSLWTQCQSLADMKFTYVV...GVSPEKSWESWWEKEHEHLRHSGKRGIATEIILSLRFFIYQYGLVYHLSITDKTQSVLVYGLSWMIIFVILGLMKGVSVGRRRLSAD...WNKIITSLREEDLIDNREMDLMLVPYSADRSLNLIQWPPFLLASKIPIAVSMAEDSLGKGQELEKRLSRDKYMKSAVEECYASFKSIINFLVLGERETMVIQNIFQRVDVHIENKAVLNELNLSAVPSLYER...46:1324 3847:1324 PREDICTED: callose synthase 1-like isoform 1 Glycine max MSYRRGSDLPPQRRILRTQTAGNLGADPILDSEVVPSSLVEIAPILRVANE

  10. Cortical involvement of marchiafava-bignami disease: a case report

    Jang, Han Won [Yeungnam University College of Medicine, Daegu (Korea, Republic of)

    2007-03-15

    Marchiafava-Bignami disease is a rare complication of chronic alcoholism and this malady typically manifests as callosal lesion. I report here on one patient with Marchiafava-bignami disease (MBD) who has symmetric restricted diffusion in both lateral-frontal cortices, in addition to the callosal lesion.

  11. The Arabidopsis lectin receptor kinase LecRK-V.5 represses stomatal immunity induced by Pseudomonas syringae pv. tomato DC3000.

    Marie Desclos-Theveniau

    2012-02-01

    Full Text Available Stomata play an important role in plant innate immunity by limiting pathogen entry into leaves but molecular mechanisms regulating stomatal closure upon pathogen perception are not well understood. Here we show that the Arabidopsis thaliana L-type lectin receptor kinase-V.5 (LecRK-V.5 negatively regulates stomatal immunity. Loss of LecRK-V.5 function increased resistance to surface inoculation with virulent bacteria Pseudomonas syringae pv tomato DC3000. Levels of resistance were not affected after infiltration-inoculation, suggesting that LecRK-V.5 functions at an early defense stage. By contrast, lines overexpressing LecRK-V.5 were more susceptible to Pst DC3000. Enhanced resistance in lecrk-V.5 mutants was correlated with constitutive stomatal closure, while increased susceptibility phenotypes in overexpression lines were associated with early stomatal reopening. Lines overexpressing LecRK-V.5 also demonstrated a defective stomatal closure after pathogen-associated molecular pattern (PAMP treatments. LecRK-V.5 is rapidly expressed in stomatal guard cells after bacterial inoculation or treatment with the bacterial PAMP flagellin. In addition, lecrk-V.5 mutants guard cells exhibited constitutive accumulation of reactive oxygen species (ROS and inhibition of ROS production opened stomata of lecrk-V.5. LecRK-V.5 is also shown to interfere with abscisic acid-mediated stomatal closure signaling upstream of ROS production. These results provide genetic evidences that LecRK-V.5 negatively regulates stomatal immunity upstream of ROS biosynthesis. Our data reveal that plants have evolved mechanisms to reverse bacteria-mediated stomatal closure to prevent long-term effect on CO(2 uptake and photosynthesis.

  12. Overexpression of AtTTP Affects ARF17 Expression and Leads to Male Sterility in Arabidopsis

    Zhi-Hao Shi; Cheng Zhang; Xiao-Feng Xu; Jun Zhu; Que Zhou; Li-Juan Ma; Jin Niu; Zhong-Nan Yang

    2015-01-01

    Callose synthesis is critical for the formation of the pollen wall pattern. CalS5 is thought to be the major synthethase for the callose wall. In the Arabidopsis anther, ARF17 regulates the expression of CalS5 and is the target of miR160. Plants expressing miR160-resistant ARF17 (35S:5mARF17 lines) with increased ARF17 mRNA levels display male sterility. Here we report a zinc finger family gene, AtTTP, which is involved in miR160 maturation and callose synthesis in Arabidopsis. AtTTP is expre...

  13. Spraying of Abscisic Acid on the Leaf Improved Drought Resistance of Plukenetia volubilis Seedling%叶面喷施脱落酸对提高星油藤幼苗耐旱性研究

    苏志龙; 罗银玲; 毕廷菊; 罗娅婷; 赵艳; 兰芹英

    2015-01-01

    为提高星油藤的抗旱性,发展其种植业,分析了2~ 50 μmol/L的脱落酸(ABA)预处理对星油藤幼苗抗旱性的影响.结果表明:ABA预处理可降低脂质过氧化程度,减缓超氧阴离子(O2)的生成速率,减少过氧化氢(H2O2)含量;提高超氧化物歧化酶(SOD)、愈创木酚过氧化物酶(GPOX)、过氧化氢酶(CAT)、抗坏血酸过氧化物酶(APX)和谷胱甘肽还原酶(GR)等抗氧化酶的活性;且ABA的最合适浓度为2 ~5 μmol/L.可见,ABA预处理可通过诱导抗氧化酶活性来提高星油藤的抗旱性.因此,外施ABA对星油藤的种植具有重要的实际应用意义.

  14. Signalling mechanisms involved in the response of two varieties of Humulus lupulus L. to soil drying: II. changes in the concentration of abscisic acid catabolites and stress-induced phytohormones

    Korovetska, H.; Novák, Ondřej; Turečková, Veronika; Hájíčková, M.; Gloser, V.

    2016-01-01

    Roč. 78, č. 1 (2016), s. 13-20. ISSN 0167-6903 R&D Projects: GA ČR GA14-34792S Keywords : ABA metabolites * ABAGE * Hop Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 1.672, year: 2014

  15. 外源ABA缓解黄瓜幼苗中低温诱导的氧化损伤%Exogenous abscisic acid alleviates low temperature-induced oxidative damage in seedlings of Cucumis sativus.L

    张颖; 蒋卫杰; 余宏军; 杨学勇

    2012-01-01

    脱落酸作为胁迫激素可提高植物对胁迫的抵抗能力,但亚适温下合理应用脱落酸提高植物抗性的研究较少.该文研究了脱落酸(ABA)预处理对亚低温环境下津研4号(低温敏感型品种)和中农27号(耐低温品种)的影响.于黄瓜三叶期分别喷施200 μmol/L ABA或清水,预处理12 h后分为2组,放入温度分别为25/18℃(昼/夜)和10/10℃(昼/夜)2个人工气候室培养7d.测定电导率、组织含水量、叶绿素含量,抗氧化酶活性以及相关酶的基因表达变化.结果表明,低温处理后,2黄瓜品种幼苗的电导率增加,组织含水量和叶绿素含量下降,过氧化物酶(POD)和超氧化物歧化酶(SOD)的活性增加,而过氧化氢酶(CAT)活性降低.与清水对照相比,ABA预处理有效的缓解了上述生理指标在低温下的变化.此外,低温处理后CAT基因表达量下调,SOD基因的表达量上调,而喷施ABA同样缓解了低温下CAT的下调表达和SOD的上调表达.说明ABA通过平衡活性氧的产生和清除来减轻低温对黄瓜幼苗的伤害,为外源ABA应用于植物抗低温生产提供理论依据.%Absicsic acid (ABA) as a kind of stress hormone has been applied to enhance a plant's resistance to various abiotic stresses,but the effect of ABA on sub-optimal temperature stress has not been clarified.The effects of ABA pretreatment on two cultivars of cucumber seedlings (chilling sensitive Jinyan 4 and chilling tolerant Zhongnong 27)under chilling stress were investigated.The cucumber seedlings were pretreated with 200 μmol/L ABA or water for 12 h,then divided into two groups and cultivated separately in two phytotrons with temperatures 25/18℃ and 10/10℃(day/night) for seven days,respectively.The level of electrolyte leakage,the tissue water content (TWC),the chlorophyll content,the antioxidant enzyme activities and the transcriptional levels of the genes encoding these enzymes were measured.The results showed that the level of electrolyte leakage was increased under chilling stress,whereas the TWC and chlorophyll content was decreased.The activities of peroxidase (POD) and superoxide dismutase (SOD) were increased,whereas the catalase (CAT) activity was decreased under chilling stress.Pretreatment with ABA alleviated the changes of physiological features in cucumber seedlings upon chilling stress.The CAT gene transcriptional level was down-regulated and the SOD gene transcriptional level was up-regulated under chilling stress.Pretreatment with ABA also mitigated the changes of gene expression.It demonstrated that ABA may play a role in alleviating the harm of chilling stress by balancing the production and scavenging of reactive oxygen species (ROS) in cucumber seedlings.The results will provide a reference for the application of ABA to enhance the resistance of cucumber to low-temperature stress.

  16. A transcript profiling approach reveals an abscisic acid-specific glycosyltransferase (UGT73C14 induced in developing fiber of Ligon lintless-2 mutant of cotton (Gossypium hirsutum L..

    Matthew K Gilbert

    Full Text Available Ligon lintless-2, a monogenic dominant cotton (Gossypium hirsutum L. fiber mutation, causing extreme reduction in lint fiber length with no pleiotropic effects on vegetative growth, represents an excellent model system to study fiber elongation. A UDP-glycosyltransferase that was highly expressed in developing fibers of the mutant Ligon lintless-2 was isolated. The predicted amino acid sequence showed ~53% similarity with Arabidopsis UGT73C sub-family members and the UDP-glycosyltransferase was designated as UGT73C14. When expressed in Escherichia coli as a recombinant protein with a maltose binding protein tag, UGT73C14 displayed enzymatic activity toward ABA and utilized UDP-glucose and UDP-galactose as the sugar donors. The recombinant UGT73C14 converted natural occurring isoform (+-cis, trans-ABA better than (+-trans, trans-ABA and (--cis, trans-ABA. Transgenic Arabidopsis plants constitutively overexpressing UGT73C14 did not show phenotypic changes under standard growth conditions. However, the increased glycosylation of ABA resulted in phenotypic changes in post-germinative growth and seedling establishment, confirming in vivo activity of UGT73C14 for ABA. This suggests that the expression level of UGT73C14 is regulated by the observed elevated levels of ABA in developing fibers of the Li 2 mutant line and may be involved in the regulation of ABA homeostasis.

  17. Transpiration, CO2 assimilation, WUE, and stomatal aperture in leaves of Viscum album (L.): Effect of abscisic acid (ABA) in the xylem sap of its host (Populus x euamericana).

    Escher, Peter; Peuke, Andreas D; Bannister, Peter; Fink, Siegfried; Hartung, Wolfram; Jiang, Fan; Rennenberg, Heinz

    2008-01-01

    Leaves of the mistletoe Viscum album (L.) show a high rate of transpiration, even when the host is under severe drought stress. The hypothesis that a strong control of ABA influx from the xylem sap of the host into the mistletoe prevents stomatal closure in mistletoe leaves was tested under the following conditions: sections of poplar twigs carrying a mistletoe were perfused with artificial xylem sap that contained different ABA concentrations and both transpiration and ABA levels were analysed in mistletoe leaves. Despite variation by a factor of 10(4), the ABA content of the host xylem did not affect ABA levels, leaf transpiration, CO(2) assimilation, WUE, or the degree of stomatal aperture in mistletoe leaves. These observations support the hypothesis of a strong control of ABA influx from the host of the xylem into the mistletoe, although degradation of ABA before it enters the mistletoe leaves cannot be excluded. This mechanism may ensure a water and nutritional status favourable for the mistletoe, even if the water status of the host is impaired. Despite the lack of short-term sensitivity of ABA levels in mistletoe leaves to even strong changes of ABA levels in the xylem sap of the host, ABA levels in mistletoe leaves were relatively high compared to ABA levels in the leaves of several tree species including poplar. Since significant transpiration of the mistletoe leaves was observed despite high ABA levels, a diminished sensitivity of the stomata of mistletoe leaves to ABA has to be concluded. The stomatal density of adaxial Viscum leaves of 89+/-23 stomata per mm is lower than those reported in a study performed at the end of the 19th century. PMID:18042393

  18. An investigation of exogenous abscisic acid on improving chilling tolerance of the seedlings of sacha inchi (Plukenetia volubilis)%外源ABA提高星油藤幼苗抗冷害能力的探讨

    罗银玲; 苏志龙; 崔现亮; 李孙洋; 兰芹英

    2014-01-01

    星油藤是热带经济作物,对冷害比较敏感.研究通过不同浓度ABA叶面喷施探讨外源ABA能否提高星油藤幼苗的抗冷害能力.在幼苗叶面喷施水或2,5,10 μmol/L和50 μmol/L的ABA溶液后,放在4℃条件下2d进行冷害处理.冷害处理导致喷施水的幼苗冷害等级提高,而2~50 μmol/L ABA溶液处理的幼苗冷害等级相对较低.冷害导致幼苗叶片中的脂质过氧化水平、超氧阴离子的生成速率及过氧化氢含量提高;而ABA处理降低了它们提高的水平.冷害导致叶片中抗氧化酶活性降低,ABA处理可增强超氧化物歧化酶、过氧化氢酶、和愈创木酚过氧化物酶、谷胱甘肽还原酶与脱氢抗坏血酸还原酶的活性;抗坏血酸过氧化物酶活性在ABA预处理后无显著变化.这些结果表明ABA可通过诱导星油藤的抗氧化酶活性来提高星油藤幼苗的冷害抗性.10μmol/L以下的ABA溶液处理能达到提高抗冷害能力的目的.

  19. Effects of pre-treatments with abscisic acid and/or benzyladenine on gas exchange of French bean, sugar beet, and maize leaves during water stress and after rehydration

    Pospíšilová, Jana; Baťková, P.

    2004-01-01

    Roč. 48, č. 3 (2004), s. 395-399. ISSN 0006-3134 R&D Projects: GA ČR GA522/02/1099 Institutional research plan: CEZ:AV0Z5038910 Keywords : Beta vulgaris * net photosynthetic rate * Phaseolus vulgaris Subject RIV: ED - Physiology Impact factor: 0.744, year: 2004

  20. 75 FR 11740 - S-Abscisic Acid, (S)-5-(1-hydroxy-2,6,6-trimethyl-4-oxo-1-cyclohex-2-enyl)-3-methyl-penta-(2Z,4E...

    2010-03-12

    ... Environmental Health Risks and Safety ] Risks (62 FR 19885, April 23, 1997). This final rule does not contain... expected in a vegetarian diet. 1. Food. Residues of ABA applied to food crops are expected to dissipate to... Findings In the Federal Register of May 6, 2009 (74 FR 20946) (FRL-8411-2), EPA issued a notice pursuant...

  1. AcEST: DK962832 [AcEST

    Full Text Available plantlets Developmental stage gametophytes with sporophytes C...ian... 51 4e-06 sp|Q9LTG5|CALS4_ARATH Callose synthase 4 OS=Arabidopsis thaliana... 47 1e-04 sp|Q5YP50|GPMA_NOCFA 2,3-bisphosph...ult : Swiss-Prot sp_hit_id Q9S9U0 Definition sp|Q9S9U0|CALSB_ARATH Callose synthase 11 OS=Arabidopsis thaliana Align length... producing significant alignments: (bits) Value sp|Q9S9U0|CALSB_ARATH Callose synthase 11 OS=Arabidopsis thal...ian... 136 7e-32 sp|Q9ZT82|CALSC_ARATH Callose synthase 12 OS=Arabidopsis thal

  2. Interhemispheric connections between primary visual areas: beyond the midline rule

    Houzel J.-C.

    2002-01-01

    Full Text Available In the last five years, a number of detailed anatomical, electrophysiological, optical imaging and simulation studies performed in a variety of non-human species have revealed that the functional organization of callosal connections between primary visual areas is more elaborate than previously thought. Callosal cell bodies and terminals are clustered in columns whose correspondence to features mapped in the visual cortex, such as orientation and ocularity, are starting to be understood. Callosal connections are not restricted to the vertical midline representation nor do they establish merely point-to-point retinotopic correspondences across the hemispheres, as traditionally believed. In addition, anatomical studies have revealed the existence of an ipsilateral component of callosal axons. The aim of this short review is to propose how these new data can be integrated into an updated scheme of the circuits responsible for assembling the primary visual field map.

  3. Facial emotion recognition in agenesis of the corpus callosum

    Bridgman, Matthew W; Brown, Warren S.; Spezio, Michael L.; Leonard, Matthew K.; Adolphs, Ralph; Paul, Lynn K

    2014-01-01

    Background: Impaired social functioning is a common symptom of individuals with developmental disruptions in callosal connectivity. Among these developmental conditions, agenesis of the corpus callosum provides the most extreme and clearly identifiable example of callosal disconnection. To date, deficits in nonliteral language comprehension, humor, theory of mind, and social reasoning have been documented in agenesis of the corpus callosum. Here, we examined a basic social ability as yet not ...

  4. The Fezf2–Ctip2 genetic pathway regulates the fate choice of subcortical projection neurons in the developing cerebral cortex

    Chen, Bin; Wang, Song S.; HATTOX, ALEXIS M.; Rayburn, Helen; Nelson, Sacha B.; McConnell, Susan K.

    2008-01-01

    Pyramidal neurons in the deep layers of the cerebral cortex can be classified into two major classes: callosal projection neurons and long-range subcortical neurons. We and others have shown that a gene expressed specifically by subcortical projection neurons, Fezf2, is required for the formation of axonal projections to the spinal cord, tectum, and pons. Here, we report that Fezf2 regulates a decision between subcortical vs. callosal projection neuron fates. Fezf2−/− neurons adopt the fate o...

  5. Asymmetrical interhemispheric connections develop in cat visual cortex after early unilateral convergent strabismus: Anatomy, physiology and mechanisms

    Emmanuel eBui Quoc

    2012-01-01

    Full Text Available In the mammalian primary visual cortex, the corpus callosum contributes to the unification of the visual hemifields that project to the two hemispheres. Its development depends on visual experience. When the latter is abnormal, callosal connections must undergo dramatic anatomical and physiological changes. However, such data are sparse and incomplete. Thus, little is known about the consequences of abnormal postnatal visual experience on the development of callosal connections and their role in unifying representation of the two hemifields. Here, the effects of early unilateral convergent strabismus (a model of abnormal visual experience were fully characterized with respect to the development of the callosal connections in cat visual cortex, an experimental model for humans. Electrophysiological responses and 3D reconstruction of single callosal axons show that abnormally asymmetrical callosal connections develop after unilateral convergent strabismus, resulting from an extension of axonal branches of specific orders in the hemisphere ipsilateral to the deviated eye and a decreased number of nodes and terminals in the other (ipsilateral to the non deviated eye. Furthermore this asymmetrical organization prevents the establishment of a unifying representation of the two visual hemifields. As a general rule, we suggest that crossed and uncrossed retino-geniculo-cortical pathways contribute in succession to the development of the callosal maps in visual cortex.

  6. New insight into silica deposition in horsetail (Equisetum arvense

    Exley Christopher

    2011-07-01

    Full Text Available Abstract Background The horsetails (Equisetum sp are known biosilicifiers though the mechanism underlying silica deposition in these plants remains largely unknown. Tissue extracts from horsetails grown hydroponically and also collected from the wild were acid-digested in a microwave oven and their silica 'skeletons' visualised using the fluor, PDMPO, and fluorescence microscopy. Results Silica deposits were observed in all plant regions from the rhizome through to the stem, leaf and spores. Numerous structures were silicified including cell walls, cell plates, plasmodesmata, and guard cells and stomata at varying stages of differentiation. All of the major sites of silica deposition in horsetail mimicked sites and structures where the hemicellulose, callose is known to be found and these serendipitous observations of the coincidence of silica and callose raised the possibility that callose might be templating silica deposition in horsetail. Hydroponic culture of horsetail in the absence of silicic acid resulted in normal healthy plants which, following acid digestion, showed no deposition of silica anywhere in their tissues. To test the hypothesis that callose might be templating silica deposition in horsetail commercially available callose was mixed with undersaturated and saturated solutions of silicic acid and the formation of silica was demonstrated by fluorimetry and fluorescence microscopy. Conclusions The initiation of silica formation by callose is the first example whereby any biomolecule has been shown to induce, as compared to catalyse, the formation of silica in an undersaturated solution of silicic acid. This novel discovery allowed us to speculate that callose and its associated biochemical machinery could be a missing link in our understanding of biosilicification.

  7. Interhemispheric Transfer in Down’s Syndrome

    C. M. J. Braun

    1992-01-01

    Full Text Available Callosal agenesics and callosotomized epileptics manifest markedly increasing simple visual reaction time (SVRT from conditions of ipsilateral to contralateral stimulus-response relation (SRR. In the contralateral SRR, a response is presumed possible because of presence of other commissures (anterior, intercollicular. The SRR effect is prolonged presumably because the remaining commissures are less efficient than the corpus callosum in relaying necessary visual or motor information. Consequently, the SRR effect is believed to correspond to callosal relay time (CRT in the normal subject. However, both callosal agenesics and callosotomy patients manifest general slowing of SVRT in addition to a prolonged SRR effect. These patients have massive extra-callosal damage which could plausibly cause both the SVRT and the CUD prolongation. If such were the case, the CRT inference would be in jeopardy. A test of the CRT inference is therefore required where patients with massive diffuse extra-callosal brain damage and normal callosi would show marked general SVRT prolongation and a normal SRR effect. Four trisomy-21 (T21 males were compared to age and sex-matched normal controls. General SVRT was highly significantly prolonged in T21, but the CUD was nearly identical in both groups.

  8. Rice8987 g_array: cDNA information: 3997 [

    Full Text Available g_3997 CG2494 >STU76610_1(U76610|pid:g4098248) Solanum tuberosum ci21A gene, promoter and comple ... te cds; cold inducible; similar to other osmotic stress ... induced gene products including: Tomato abscisic s ... on Number L20756 and to Solanum chacoense abscisic stress ... ripening protein encoded by GenBank Accession Numb ...

  9. Rice8987Corresponding Table(f_g_primer): g_3997 [

    Full Text Available g_3997 3UTR_3997 CG2494 C27651 AU100845 >STU76610_1(U76610|pid:g4098248) Solanum tuberosum ci21A ... lete cds; cold inducible; similar to other osmotic stress ... induced gene products including: Tomato abscisic s ... on Number L20756 and to Solanum chacoense abscisic stress ... ripening protein encoded by GenBank Accession Numb ...

  10. AcEST: DK962505 [AcEST

    Full Text Available TrEMBL tr_hit_id Q1HGG1 Definition tr|Q1HGG1|Q1HGG1_9ROSI Abscisic acid responsive element-binding protein 2 OS=Populus suav...ROSI Abscisic acid responsive element-binding protein 2 OS=Populus suaveolens GN=ABF2 PE=2 SV=1 Length = 406

  11. Reference: REGION1OSOSEM [PLACE

    Full Text Available ic acid and the transcriptional activator VP1: analysis of cis-acting promoter elements required for regulat...REGION1OSOSEM Hattori T, Terada t, Hamasuna S Regulation of the Osem gene by abscis...ion by abscisic acid and VP1 Plant J 7: 913-925 (1995) PubMed: 7599651; GenBank: U22102 ...

  12. Gene : CBRC-CJAC-01-0155 [SEVENS

    Full Text Available al stress-inducible protein emb|CAA42554.1| environmental stress and abscisic acid ...CBRC-CJAC-01-0155 Novel UN D UNKNOWN GRPA_MEDFA 1e-06 35% sp|Q09134|GRPA_MEDFA Abscisic acid and environment

  13. NCBI nr-aa BLAST: CBRC-CJAC-01-0155 [SEVENS

    Full Text Available CBRC-CJAC-01-0155 sp|Q09134|GRPA_MEDFA Abscisic acid and environmental stress-induc...ible protein emb|CAA42554.1| environmental stress and abscisic acid inducible protein [Medicago sativa subsp. falcata] Q09134 2e-05 35% ...

  14. Effects on Physiological Characteristics of Maize Seedlings under Drought Stress with Salicy Acid and Abscisic Acid%水杨酸和脱落酸在干旱胁迫下对玉米幼苗生理生化特性的影响

    彭浩; 黄跃才; 王晓强; 宋文路; 师艳秋

    2016-01-01

    [目的]研究水杨酸和脱落酸在干旱胁迫下对玉米幼苗生理生化特性的影响.[方法]采用20%聚乙二醇(PEG6000)模拟干旱胁迫,使用不同浓度的水杨酸(SA)、脱落酸(ABA)的配比组合喷施玉米幼苗,通过测定幼苗叶绿素和可溶性糖的含量、过氧化物酶(POD)活性等生理指标,研究水杨酸及脱落酸对干旱胁迫下玉米幼苗生长的影响.[结果]结果表明,干旱胁迫下,单独使用一定浓度的水杨酸及脱落酸喷施幼苗,其幼苗叶片的叶绿素和可溶性糖的含量、POD活性均显著升高,且二者配比组合(0.5~ 1.0mmol/L SA和4.0 mg/LABA)具有显著的缓解干旱的效果.[结论]为作物耐旱机制的研究提供了理论依据和实践参考.

  15. Plant, cell, and molecular mechanisms of abscisic-acid regulation of stomatal apertures. A new mechanism for the regulation of stomatal-aperture size in intact leaves: Accumulation of mesophyll-derived sucrose in the guard-cell wall of Vicia faba L.

    Lu, P.; Outlaw, W.H. Jr.; Smith, B.G.; Freed, G.A.

    1996-12-31

    At various times after pulse labeling Vicia faba L. leaflets with {sup 14}CO{sub 2}, whole-leaf pieces and rinsed epidermal peels were harvested and subsequently processed for histochemical analysis. Cells dissected from whole leaf retained apoplastic contents whereas those from rinsed peels contained only cytoplastic contents. Sucrose specific radioactivity peaked in palisade cells, 111 GBq{center_dot}mol{sup {minus}1}, at 20 min. In contrast, the {sup 14}C content and sucrose specific radioactivity were very low in guard cells for 20 min, implying little CO{sub 2} incorporation; both then peaked at 40 min. The guard-cell apoplast had a high maximum sucrose specific radioactivity and a high sucrose influx rate. These and other comparisons implied the presence of (a) multiple sucrose pools in mesophyll cells, (b) a localized mesophyll-apoplast region that exchanges with phloem and stomata, and (c) mesophyll-derived sucrose in guard-cell walls sufficient to diminish stomatal opening by {approximately} 4 {micro}m. Factors expected to enhance sucrose accumulation in guard-cell walls are (a) high transpiration rate, which closes stomata, and (b) high apoplastic sucrose concentration, which is elevated when mesophyll-sucrose efflux exceeds translocation. Therefore, multiple physiological factors are integrated in the attenuation of stomatal-aperture size by this previously unrecognized mechanism.

  16. Corpus callosum arteriovenous malformation with persistent trigeminal artery.

    Mohanty, Chandan B; Devi, B Indira; Somanna, Sampath; Bhat, Dhananjaya I; Dawn, Rose

    2011-12-01

    A 13-year-old boy presented with an intracerebral haematoma secondary to a large corpus callosal arteriovenous malformation (AVM) with an associated persistent trigeminal artery, and was treated with Gamma-Knife Radiosurgery for the AVM. This report discusses the embryological basis, radiological features and various classifications of this rare vascular anomaly. PMID:21501055

  17. Huntington's disease: visuomotor disturbance in patients and offspring.

    Oepen, G; Mohr, U.; Willmes, K; Thoden, U

    1985-01-01

    In 15 patients with Huntington's disease, 17 offspring at risk and 63 healthy controls, visuomotor performances were assessed by quantitative (statistical) and qualitative analysis. The much enlarged error score of the nondominant left hand in patients with Huntington's disease was explained as callosal dyspraxia. Five of the 17 offspring revealed results similar to that of the patients.

  18. A complementary bioinformatics approach to identify potential plant cell wall glycosytransferase encoding genes

    Egelund, Jack; Skjøt, Michael; Geshi, Naomi;

    2004-01-01

    Plant cell wall (CW) synthesizing enzymes can be divided into the glycan (i.e. cellulose and callose) synthases, which are multimembrane spanning proteins located at the plasma membrane, and the glycosyltransferases (GTs), which are Golgi localized single membrane spanning proteins, believed...

  19. MIR137HG risk variant rs1625579 genotype is related to corpus callosum volume in schizophrenia

    Patel, V.S.; Kelly, S.; Wright, C.; Gupta, C.N.; Arias Vasquez, A.; Perrone-Bizzozero, N.; Ehrlich, S.; Wang, L.; Bustillo, J.R.; Morris, D.; Corvin, A.; Cannon, D.M.; McDonald, C.; Donohoe, G.; Calhoun, V.D.; Turner, J.A.

    2015-01-01

    Genome-wide association studies implicate the MIR137HG risk variant rs1625579 (MIR137HGrv) within the host gene for microRNA-137 as a potential regulator of schizophrenia susceptibility. We examined the influence of MIR137HGrv genotype on 17 subcortical and callosal volumes in a large sample of indi

  20. Corpus callosum atrophy in patients with mild Alzheimer's disease

    Frederiksen, Kristian Steen; Garde, Ellen; Skimminge, Arnold;

    2011-01-01

    Several studies have found atrophy of the corpus callosum (CC) in patients with Alzheimer's disease (AD). However, it remains unclear whether callosal atrophy is already present in the early stages of AD, and to what extent it may be associated with other structural changes in the brain, such as...