scholarly journals Changes in abscisic acid metabolism in relation to the maturation of grapevine (Vitis vinifera L., cv. Mencía) somatic embryos

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Yosvanis Acanda ◽  
Óscar Martínez ◽  
María Jesús Prado ◽  
María Victoria González ◽  
Manuel Rey
Keyword(s):  
Abscisic Acid ◽  
Somatic Embryos ◽  
Expression Profiles ◽  
Semipermeable Membrane ◽  
Precocious Germination ◽  
Exogenous Aba ◽  
Differentiation Medium ◽  
Conversion Rates ◽  
Aba Content ◽  
Endogenous Aba

Abstract Background Somatic embryogenesis in grapevines is a complex process that depends on many physiological and genetic factors. One of its main limitations is the process of precocious germination of the somatic embryos in differentiation medium. This process lowers plant conversion rates from the somatic embryos, and it is probably caused by a low endogenous abscisic acid (ABA) content. Results Precocious germination of the somatic embryos was successfully avoided by culturing grapevine cv. Mencía embryogenic aggregates over a semipermeable membrane extended on top of the differentiation medium. The weekly analysis of the endogenous ABA and ABA-glucosyl ester (ABA-GE) contents in the aggregates showed their rapid accumulation. The expression profiles of 9-cis-epoxycarotenoid dioxygenase (VvNCED1), 8′-hydroxylase (VvHyd2), UDP-glucosyltransferase (VvUGT) and β-glucosidase (VvBG2) genes in grapevine revealed that the occurrence of a first accumulation peak of endogenous ABA in the second week of culture over the semipermeable membrane was mainly dependent on the expression of the VvNCED1 gene. A second increase in the endogenous ABA content was observed in the fourth week of culture. At this point in the culture, our results suggest that of those genes involved in ABA accumulation, one (VvNCED1) was repressed, while another (VvBG2) was activated. Similarly, of those genes related to a reduction in ABA levels, one (VvUGT) was repressed while another (VvHyd2) was activated. The relative expression level of the VvNCED1 gene in embryogenic aggregates cultured under the same conditions and treated with exogenous ABA revealed the significant downregulation of this gene. Conclusions Our results demonstrated the involvement of ABA metabolism in the control of the maturation of grapevine somatic embryos cultured over a semipermeable membrane and two important control points for their endogenous ABA levels. Thus, subtle differences in the expression of the antagonistic genes that control ABA synthesis and degradation could be responsible for the final level of ABA during the maturation of grapevine somatic embryos in vitro. In addition, the treatment of somatic embryos with exogenous ABA suggested the feedback-based control of the expression of the VvNCED1 gene by ABA during the maturation of grapevine somatic embryos.

Endogenous abscisic acid and precocious germination of developing soybean seeds

2007 ◽  
Vol 17 (3) ◽  
pp. 165-174 ◽  
Author(s):  
Carlos O. Gosparini ◽  
Hector A. Busilacchi ◽  
Paolo Vernieri ◽  
Eligio N. Morandi
Keyword(s):  
Abscisic Acid ◽  
Soybean Seed ◽  
Quantitative Relationship ◽  
In Planta ◽  
Precocious Germination ◽  
Developing Seeds ◽  
Before And After ◽  
Substantial Decline ◽  
Aba Content ◽  
Endogenous Aba

AbstractThe germination of developing seeds is very uncommon and is generally associated with deficiencies in abscisic acid (ABA) synthesis or sensitivity. This paper examines the quantitative relationship between the inhibition of precocious germination and endogenous ABA in the embryonic axis (ABAa) of hydrated soybean [Glycine max (L.) Merr.] seeds, isolated after the completion of histodifferentiation and before the beginning of dehydration, as well as the magnitude and evolution of axis sensitivity to endogenous ABA during that period. Developing seeds harvested at 25, 30, 35, 40 and 45 d after anthesis (DAA) were subjected to incubation or washing to induce changes in ABA content. ABA content was measured by radioimmunoassay, using a monoclonal antibody against free ABA. Germinability was measured as the time to 50% germination (t50). Washing and incubation induced eight- and twofold increases, respectively, in the rate of ABAa decline compared with the in planta ABAa decline. The threshold ABAa for inhibition of precocious germination (ABAc) increased slightly from 25 to 40 DAA [1.15–1.66 μg ABA (g DW)− 1]. This contrasted with the substantial decline in ABAa [10.90–2.07 μg ABA (g DW)− 1] during the same period, and indicated that sensitivity to endogenous ABA of hydrated seeds was initially high and diminished slowly during development. The relationship between (ABAa–ABAc) and t50 was linear for immature seeds incubated before and after washing. Below the ABAc, there were no differences in the t50 of 25–45 DAA seeds. The ABAa contribution to the control of precocious soybean seed germination was evident, although other potentially interacting factors were also present.

Molybdenum deficiency in wheat results in lower dormancy levels via reduced ABA

1994 ◽  
Vol 4 (3) ◽  
pp. 329-333 ◽  
Author(s):  
A. T. Modi ◽  
A. L. P. Cairns
Keyword(s):  
Abscisic Acid ◽  
Field Experiment ◽  
Nutrient Solution ◽  
Foliar Application ◽  
Flag Leaf ◽  
Foliar Spray ◽  
Leaf Stage ◽  
Enhanced Sensitivity ◽  
Aba Content ◽  
Endogenous Aba

AbstractWheat which was grown in acid-washed sand and irrigated with a molybdenum-free nutrient solution was treated with various concentrations of molybdenum (Mo) as a foliar spray at the flag leaf stage. At maturity, dormancy levels and abscisic acid (ABA) content of the seed were determined. Seed dormancy and ABA content increased with increasing rates of Mo application. In a field experiment, wheat (cv. SST 66) was treated with 100 ppm Mo by foliar application at the flag leaf stage. Embryos were tested for sensitivity to exogenously applied ABA. Embryos from Mo-treated plants showed enhanced sensitivity to ABA-induced inhibition of germination. The Mo application also resulted in significantly higher levels of endogenous ABA and Mo in the seeds. It is postulated that Mo deficiency leads to a lack of dormancy in wheat via reduced synthesis of ABA.

Vegetation-derived abscisic acid and four terpenes enforce dormancy in seeds of the post-fire annual,Nicotiana attenuata

2002 ◽  
Vol 12 (4) ◽  
pp. 239-252 ◽  
Author(s):  
Bernd Krock ◽  
Sybille Schmidt ◽  
Christian Hertweck ◽  
Ian T. Baldwin
Keyword(s):  
Abscisic Acid ◽  
Environmental Control ◽  
Wood Smoke ◽  
Nicotiana Attenuata ◽  
Germination Inhibitors ◽  
Physiological Basis ◽  
Fire Environment ◽  
Aba Content ◽  
Aba Biosynthesis ◽  
Endogenous Aba

AbstractThe native tobacco,Nicotiana attenuata, synchronizes its germination with the immediate post-fire environment with a combination of germination stimulants found in wood smoke and inhibitors from the unburned litter of the dominant vegetation. The inhibitors override the stimulants and prevent seeds from germinating maladaptively in unburned habitats adjacent to burns. To understand the physiological basis of this environmental control of germination, we tested several previously isolated signals, phytohormones and their respective biosynthesis inhibitors. The germination inhibitors methyl jasmonate (MeJA, a constituent of sagebrush litter), bornane-2,5-dione (BD, a constituent of juniper litter extract, JLE) and JLE did not alter abscisic acid (ABA) content of imbibed seeds. Treatment with the ABA biosynthesis inhibitor, fluridone, inhibited the dormancy-inducing effects of BD, JLE and MeJA, but surprisingly did not affect endogenous ABA levels in treated seeds. However, ABA leached from litter of the species, which dominate the plant community before fires, plays an important role in germination control. We conclude thatN. attenuataseeds, which can lie dormant in the soil for 150 years between fires, time their germination with the post-fire environment by responding to smoke, ABA and four terpenes (BD, 1,8-cineole, β-thujaplicin and camphor) leaching from the litter of the dominant vegetation.

scholarly journals Functional analysis of TaABF1 during abscisic acid and gibberellin signalling in aleurone cells of cereal grains

2013 ◽  
Vol 23 (2) ◽  
pp. 89-98 ◽  
Author(s):  
Lauren J. Harris ◽  
Sarah A. Martinez ◽  
Benjamin R. Keyser ◽  
William E. Dyer ◽  
Russell R. Johnson
Keyword(s):  
Transcription Factor ◽  
Abscisic Acid ◽  
Post Translational Modification ◽  
Exogenous Aba ◽  
Aleurone Cells ◽  
Low Levels ◽  
Activity Induction ◽  
Hormone Signalling ◽  
Endogenous Aba

AbstractThe wheat transcription factor TaABF1 physically interacts with the protein kinase PKABA1 and mediates both abscisic acid (ABA)-induced and ABA-suppressed gene expression. In bombarded aleurone cells of imbibing grains, the effect of TaABF1 in down-regulating the gibberellin (GA)-induced Amy32b promoter was stronger in the presence of exogenous ABA. As these grains contained low levels of endogenous ABA, the effect of TaABF1 may also be mediated by ABA-induced activation even in the absence of exogenous ABA. Levels of TaABF1 protein decreased slightly during imbibition of afterripened grains. However, TaABF1 levels (especially in aleurone layers) were not substantially affected by exogenous ABA or GA, indicating that changes in TaABF1 protein level are not an important part of regulating its role in hormone signalling. We found that TaABF1 was phosphorylated in vivo in aleurone cells, suggesting a role for post-translational modification in regulating TaABF1 activity. Induction of Amy32b by overexpression of the transcription factor GAMyb could not be prevented by TaABF1, indicating that TaABF1 acts upstream of GAMyb transcription in the signalling pathway. Supporting this view, knockdown of TaABF1 by RNA interference resulted in increased expression from the GAMyb promoter. These results are consistent with a model in which TaABF1 is constitutively present in aleurone cells, while its ability to down-regulate GAMyb is regulated in response to ABA.

scholarly journals   Role of abscisic acid and drought stress on the activities of antioxidant enzymes in wheat

2012 ◽  
Vol 58 (No. 4) ◽  
pp. 181-185 ◽  
Author(s):  
A. Bano ◽  
F. Ullah ◽  
A. Nosheen
Keyword(s):  
Abscisic Acid ◽  
Drought Stress ◽  
Seed Treatment ◽  
Oxygen Species ◽  
Wheat Cultivars ◽  
Drought Tolerant ◽  
Relative Water ◽  
Aba Content ◽  
Endogenous Aba

The effect of drought stress and abscisic acid (ABA) applied at tillering stage (55 days after sowing) was compared in 2 wheat cultivars differing in drought tolerance. The activities of superoxide dismutase (SOD) and peroxidase (POD) and contents of endogenous ABA in plants were measured at 3 days of drought stress in cv. Chakwal-97 (drought tolerant) and cv. Punjab-96 (drought susceptible). ABA was applied at 10<sup>&ndash;6</sup> mol/L as presowing seed treatment for 18 h. Drought tolerant cultivar has a more efficient mechanism to scavenge reactive oxygen species as shown by a significant increase in the activity of antioxidant enzyme SOD. Under drought stress, ABA significantly increased the activities of SOD and POD, showing a significant decline on rewatering. The relative water content was significantly increased by ABA priming under drought stress in both wheat cultivars. The sensitive cultivar exhibiting lower endogenous ABA content was more responsive to ABA priming. On rewatering, the magnitude of recovery from drought stress was greater in tolerant cultivar. ABA was highly effective in improving grain weight of tolerant cultivar under drought stress. &nbsp;

Reduced embryo sensitivity to abscisic acid in a sprouting-susceptible sorghum (Sorghum bicolor) variety is associated with altered ABA signalling

2007 ◽  
Vol 17 (2) ◽  
pp. 81-90 ◽  
Author(s):  
Nicolás Gualano ◽  
Fernando Carrari ◽  
María Verónica Rodríguez ◽  
Laura Pérez-Flores ◽  
Rodolfo Sánchez ◽  
...  
Keyword(s):  
Abscisic Acid ◽  
Sorghum Bicolor ◽  
Developmental Stages ◽  
Signal Transduction Pathway ◽  
Transduction Pathway ◽  
Aba Signal Transduction ◽  
Aba Sensitivity ◽  
Two Stages ◽  
Aba Content ◽  
Endogenous Aba

AbstractIn the work reported in this paper, we attempted to elucidate the nature of the different abscisic acid (ABA) sensitivities presented by developing embryos from sorghum [Sorghum bicolor (L.) Moench] lines with contrasting pre-harvest sprouting (PHS) behaviour (Redland B2, susceptible; IS 9530, resistant). We explored two different hypotheses for a possible mechanism: (1) a different functionality of the ABA signalling pathway, and (2) a different rate of ABA degradation/conjugation in the apoplast of embryos from these genotypes. To assess the first possibility, we used an ABA-responsive gene (Rab17) as a reporter of changes in endogenous ABA content, which were artificially induced in embryos from both genotypes by means of fluridone application immediately after anthesis, to reduce ABA content, and embryo incubation in the presence of ABA. A defect in ABA signalling should be seen as a level of Rab17 expression that is independent of endogenous ABA content. For testing the second possibility at two stages of development, embryos from both lines were isolated and incubated in water for different periods. ABA concentrations in embryos and the incubation media were quantified through radioimmunoassay. In contrast to our findings for the resistant IS 9530 line, Rab17 expression did not respond to changes in ABA levels in sensitive Redland B2 embryos. The ABA degradation/conjugation rates in embryos and incubation media did not show clear differences between sorghum lines for any of the developmental stages analysed. These results suggest that a disruption in the ABA signal transduction pathway in Redland B2 underlies the low ABA sensitivity shown by embryos from this line.

scholarly journals Bermudagrass Freezing Tolerance Associated with Abscisic Acid Metabolism and Dehydrin Expression during Cold Acclimation

2008 ◽  
Vol 133 (4) ◽  
pp. 542-550 ◽  
Author(s):  
Xunzhong Zhang ◽  
Kehua Wang ◽  
Erik H. Ervin
Keyword(s):  
Abscisic Acid ◽  
Cold Acclimation ◽  
Freezing Tolerance ◽  
Cold Hardiness ◽  
Management Practices ◽  
Cynodon Dactylon ◽  
Freezing Injury ◽  
Exogenous Aba ◽  
Aba Metabolism ◽  
Aba Content

Recent advances in bermudagrass [Cynodon dactylon (L.) Pers. var. dactylon] breeding and cultural management practices have enabled its use as a sports surface in U.S. Department of Agriculture cold hardiness zones 5 and 6. Use of these more cold-hardy bermudagrass cultivars further into transition- and cool-season zones increases the probability of freezing injury and increases the need for an improved understanding of physiological responses to chilling and freezing temperatures. Abscisic acid (ABA) has been shown to increase during cold acclimation (CA) and play a role in dehydration tolerance. This study investigated changes in ABA metabolism and dehydrin expression during CA and their association with freezing tolerance in four bermudagrass cultivars. Two cold-tolerant (‘Patriot’ and ‘Riviera’) and two relatively cold-sensitive (‘Tifway’ and ‘Princess’) cultivars were either subjected to CA at 8 °C day/4 °C night with a light intensity of 250 μmol·m−2·s−1 over a 10-h photoperiod for 21 days or maintained at 28 °C day/24 °C night over a 12-h photoperiod. In a separate study, exogenous ABA at 0, 50, 100, and 150 μm was applied to ‘Patriot’ bermudagrass without CA. ABA content in leaf and stolon tissues increased substantially during the first week of CA and remained relatively stable thereafter. ‘Patriot’ and ‘Riviera’ had greater ABA content and less stolon electrolyte leakage (EL) relative to ‘Tifway’ and ‘Princess’. Expression of a 25 kDa dehydrin protein increased during CA in all four cultivars. A significant correlation was found between ABA content and freezing tolerance. Exogenously applying ABA to ‘Patriot’ at 50, 100, and 150 μm significantly increased endogenous ABA content and the 25 kDa dehydrin expression and reduced stolon EL. The results suggest that alteration of ABA metabolism during CA is closely associated with freezing tolerance. Selection and use of cultivars with substantial accumulation of ABA and certain dehydrins during CA or in response to exogenous ABA could improve bermudagrass persistence in transition zone climates.

scholarly journals Differential Function of Endogenous and Exogenous Abscisic Acid during Bacterial Pattern-Induced Production of Reactive Oxygen Species in Arabidopsis

2019 ◽  
Vol 20 (10) ◽  
pp. 2544 ◽  
Author(s):  
Leitao Tan ◽  
Qiuping Liu ◽  
Yufeng Song ◽  
Guangzhen Zhou ◽  
Linli Luan ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Abscisic Acid ◽  
Plant Disease Resistance ◽  
Plant Pathogens ◽  
Reactive Oxygen ◽  
Defense Responses ◽  
Dual Function ◽  
Oxygen Species ◽  
Exogenous Aba ◽  
Endogenous Aba

Abscisic acid (ABA) plays important roles in positively or negatively regulating plant disease resistance to pathogens. Here, we reassess the role of endogenous and exogenous ABA by using: 35S::ABA2, a previously reported transgenic Arabidopsis line with increased endogenous ABA levels; aba2-1, a previously reported ABA2 mutant with reduced endogenous ABA levels; and exogenous application of ABA. We found that bacterial susceptibility promoted by exogenous ABA was suppressed in 35S::ABA2 plants. The 35S::ABA2 and aba2-1 plants displayed elevated and reduced levels, respectively, of bacterial flagellin peptide (flg22)-induced H2O2. Surprisingly, ABA pre-treatment reduced flg22-induced H2O2 generation. Exogenous, but not endogenous ABA, increased catalase activity. Loss of nicotinamide adenine dinucleotide phosphate oxidase genes, RBOHD and RBOHF, restored exogenous ABA-promoted bacterial susceptibility of 35S::ABA2 transgenic plants. In addition, endogenous and exogenous ABA had similar effects on callose deposition and salicylic acid (SA) signaling. These results reveal an underlying difference between endogenous and exogenous ABA in regulating plant defense responses. Given that some plant pathogens are able to synthesize ABA and affect endogenous ABA levels in plants, our results highlight the importance of reactive oxygen species in the dual function of ABA during plant-pathogen interactions.

scholarly journals Abscisic Acid Accumulation in Leaves and Cultured Cells during Heat Acclimation in Grapes

HortScience ◽  
1993 ◽  
Vol 28 (1) ◽  
pp. 50-52 ◽  
Author(s):  
Mageed Abass ◽  
C.B. Rajashekar
Keyword(s):  
Abscisic Acid ◽  
Heat Tolerance ◽  
Cultured Cells ◽  
Tolerance Induction ◽  
Heat Acclimation ◽  
Temperature Acclimation ◽  
Maximum Heat ◽  
Exogenous Aba ◽  
Acid Accumulation ◽  
Endogenous Aba

Heat tolerance and endogenous ABA levels in leaves and cultured grape cells (Vitis spp., cultivars Venus and Veeblanc) were evaluated during beat acclimation. Plants and cultured cells were acclimated at 38 and 36C, respectively. Heat tolerance increased rapidly after exposing plants or cells to acclimation temperatures, reaching a maximum after 10 to 16 hours and 10 to 12 hours for leaves and cultured cells, respectively. Free and bound ABA levels increased sharply during the first hour of heat acclimation, before leaves and cultured cells reached their maximum beat tolerance. The increase in ABA during heat acclimation was 2- to 3-fold that of the nonacclimated control, and the time of the ABA accumulation peak in tissue roughly corresponded to the maximum heat tolerance in leaves and cultured cells. Heat tolerance was induced in cultured cells by exogenous ABA application. Heat tolerance increased significantly after 24 hours of ABA application at 7.6 or 9.5 μm. The results suggest that ABA may be a factor in high-temperature acclimation and beat-tolerance induction in grapes. Chemical name used: abscisic acid (ABA).

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