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At least 19 recordsLinked to original sources
PubMed1976

The influence of gibberellic acid and abscisic acid on cell and tissue differentiation of bean callus.

Bean callus was induced to form roots (tissue differentiation) and vascular nodules (cell differentiation) by lowering the ratio of auxin to cytokinin in the growth medium. Both types of differentiation were inhibited by the addition of abscisic acid (at concentrations greater than I muM) to induction medium. Initiation of differentiation was inhibited, but its subsequent development was not, and the inhibition was not affected by the addition of gibberellic acid. Addition of gibberellic acid (GA) alone to induction medium stimulated tissue differentiation, although cell differentiation was unaffected (30 muM GA) or inhibited (45 muM GA) and its onset was delayed at both concentrations. Root initiation was also stimulated by gibberellic acid (0.I-45 muM) at an auxin-to-kinin ratio 10 times that normally optimal for cell differentiation. The phenylalanine ammonia lyase (PAL) activity of the calluses was closely correlated with the amount of cell differentiation which had occurred, and measurement of this confirmed that gibberellic acid delayed the initiation of cell differentiation. The increase and subsequent decline of PAL and betaI leads to 3 glucan synthetase activities, normally induced by transfer to induction medium, was abolished by abscisic acid. Addition of gibberellic acid did not affect the betaI leads to 3 glucan synthetase activity.

Abscisic Acid↗
PubMed2026

Genome-Wide Analysis of the PYL Gene Family and Its Expression Dynamics in Response to Abscisic Acid in Tomato.

The plant hormone abscisic acid (ABA) plays a crucial role throughout the plant life cycle and in adaptive responses to environmental stresses. The pyrabactin resistance 1-like (PYR/PYL/RCAR) proteins act as key regulators in the ABA signal transduction pathway by functioning as direct receptors for ABA. Although PYL genes have been identified in a variety of plant species, their evolutionary and structural characteristics in tomatoes (Solanum lycopersicum) remain elusive. To address this gap, we identified nine SlPYL genes, which were classified into three subfamilies: I (two genes), II (three genes), and III (four genes), and their encoded proteins were predicted to be primarily localized in the cytosol and chloroplast. Structural analysis revealed diverse exon-intron organizations along with five conserved motifs. All identified SlPYLs contained the START domain (PF10604), validating their identity as actual PYL proteins. Prediction of cis-acting regulatory elements in SlPYL's promoter regions was found to be associated with light responsiveness, hormone signaling, stress responses, and plant growth and development. Prediction of post-translational modification sites indicated that SlPYLs are predominantly phosphorylated and acetylated at serine and lysine residues, respectively. Tertiary structure modeling demonstrated conserved three-dimensional architectures among SlPYL proteins, supporting their functional conservation. Expression profiling revealed that specific SlPYL genes exhibit distinct expression patterns across different tissues (root, leaf, and bud) following ABA treatment, indicating functional diversification. Considering the well-established negative correlation between ABA accumulation and bud outgrowth, the ABA-induced differential expression (3~5-fold) of some SlPYL genes (SlPYL3, SlPYL4, SlPYL7, and SlPYL8), particularly in bud tissues after 24 hpt, suggests a potential role in ABA-mediated suppression of bud outgrowth. However, these functional inferences are primarily based on genome-wide computational analyses and expression profiling and therefore require further experimental validation.

Solanum lycopersicum↗
PubMedDate not supplied

Abscisic acid studied by fluorescent techniques.

Crude analytical abscisic acid (ABA) exhibited fluorescence (lambdaex 340, lambdaem 425 nm). The results demonstrated a relationship between fluorescence response and ABA concentration, in the range of 0.04-0.38 microgram/ml. Chromatographic purification increased the emission signal, and oxidation induced by adding a sulphuric acid: ethanol (1:1) mixture also increased and displaced it (lambdaex 450, lambdaem 495 nm). Using these properties, a fluorimetric method for identification and evaluation of ABA, had been developed, and used for inhibitor recognition in P. pinea seed coats.

Abscisic Acid↗
PubMed1979

[Uptake of (14C) leucine and protein synthesis in potato tuber buds and effect of abscisic acid on these processes].

The uptake of [14C] leucine and its incorporation into proteins of dormant and growing potato tuber buds were studied. It was found that the label uptake was increased at the beginning of the growth period, whereas the dynamics of this process were not changed in comparison with the dormant buds samples. The rate of [14C] leucine incorporation into proteins was increased in the growing buds; this increase was not, however, due to the increase in the uptake of the labelled precursor and was probably caused by activation of the protein synthesis. In contrast, the activation of protein synthesis was accompanied by changses is the dynamic incorporation of [14C] leucine into the protein at the end of dormancy. The effect of abscisic acid (10(-7) M) on the protein synthesis was not connected with its action of the uptake of labelled precursor and depended on the physiological state of buds and incubation time. A possible mechanism of regulatory effect of abscisic acid on protein synthesis in potato tuber buds is discussed.

Abscisic Acid↗
PubMed2026

Abscisic acid promotes RBOH-dependent reactive oxygen species production and lignin biosynthesis in pears via the PuABI5-PuMYB169 module.

Pear stone cell lignification, a critical determinant of fruit texture and quality, is regulated by developmental and environmental cues, with abscisic acid (ABA) playing a central role. However, the molecular mechanisms underlying its role in reactive oxygen species (ROS)-mediated lignification remain unclear. Here, we show that PuABI5, a key component in ABA signaling, directly combines with PuMYB169, the master regulator of stone cell lignification, to modulate ROS production and lignin biosynthesis in pear fruit. Exogenous application of ABA enhances H2O2 and lignin accumulation in both pear fruits and calli, and ABA-activated PuABI5 positively regulates stone cell lignification. We demonstrate that ABA-induced PuABI5 binds directly to the PuMYB169 promoter and activates its expression to promote the transcription of PuRBOHF and lignin-related genes, thereby enhancing ROS production and lignin accumulation. Notably, PuABI5 interacted with PuMYB169 to enhance the induction of PuRBOHF expression, leading to elevated levels of H2O2, which feedback to strengthen the interaction between PuABI5 and PuMYB169. Collectively, our findings elucidate that ABA induces ROS-mediated lignification of stone cells in pears by activating the PuABI5-PuMYB169 transcriptional module.

Lignin↗
PubMed2026

DNA hypermethylation of abscisic-acid-related genes helps enhance the cold tolerance of tetraploid rice.

Polyploid plants exhibit enhanced stress resistance and superior adaptability to extreme environments, but the underlying molecular mechanisms remain incompletely understood. Here we confirm that tetraploid rice exhibits stronger cold tolerance than diploid rice. This improved tolerance is mediated by reduced malondialdehyde accumulation, elevated antioxidant enzyme activity, and epigenetic regulation of genes involved in abscisic acid (ABA) biosynthesis and signaling. Under cold stress, tetraploid rice induces stress-responsive genes (especially in the ABA pathway) more rapidly and to higher levels than diploid rice. This enhanced gene expression coincides with increased endogenous ABA accumulation. Furthermore, polyploidization and cold stress synergistically induce high methylation at CG, CHG, and CHH sites in genes and transposons (TEs). Notably, the methylation level of class II TEs in tetraploid rice is significantly higher than in diploid rice under low temperatures. To suppress TE activation in gene promoter regions under cold stress, tetraploid rice enhances the methylation level of ABA pathway-related gene promoters, thereby silencing TEs and maintaining genome stability. Collectively, these results enrich the theoretical understanding of the strong stress tolerance in polyploid plants and provide theoretical support for breeding cold-tolerant polyploid rice varieties.

ABA↗
PubMed1977

Repression of asexual embryogenesis in vitro by some plant growth regulators.

A factor that represses asexual embryogenesis has been observed in the Rutaceae, with particularly high concentrations in the naturally monoembryonic cultivars. This investigation was an initial step towards identifying the factor. Citrus reticulata Blanco Ponkan mandarin nucellus explants and Daucus carota L. 'Queen Anne's Lace' callus were employed to examine effects of known plant growth regulators and to determine possible identity of one or more of them with the repressive factor. The chalazal halves of ovules of C. media L. 'Citron of Commerce' were used as control repressor source. Embryo initiation and growth of both test tissues were depressed markedly by 2,4-D, abscisic acid and ethephon. Slight inhibitions were obtained with IAA, kinetin and gibberellic acid. Recovery from the repressor did not occur readily in Citrus nucellus following recultures in citron-ovule-free medium; carrot callus resumed normal embryogenesis immediately upon transfer to suppressor-free medium. The repression by natural sources apparently involved the combined action of some or all natural hormones that are generically related to the above.

2,4-Dichlorophenoxyacetic Acid↗
PubMed2024

PSEUDO-RESPONSE REGULATOR 3b and transcription factor ABF3 modulate abscisic acid-dependent drought stress response in soybean.

The circadian system plays a pivotal role in facilitating the ability of crop plants to respond and adapt to fluctuations in their immediate environment effectively. Despite the increasing comprehension of PSEUDO-RESPONSE REGULATORs and their involvement in the regulation of diverse biological processes, including circadian rhythms, photoperiodic control of flowering, and responses to abiotic stress, the transcriptional networks associated with these factors in soybean (Glycine max (L.) Merr.) remain incompletely characterized. In this study, we provide empirical evidence highlighting the significance of GmPRR3b as a crucial mediator in regulating the circadian clock, drought stress response, and abscisic acid (ABA) signaling pathway in soybeans. A comprehensive analysis of DNA affinity purification sequencing and transcriptome data identified 795 putative target genes directly regulated by GmPRR3b. Among them, a total of 570 exhibited a significant correlation with the response to drought, and eight genes were involved in both the biosynthesis and signaling pathways of ABA. Notably, GmPRR3b played a pivotal role in the negative regulation of the drought response in soybeans by suppressing the expression of abscisic acid-responsive element-binding factor 3 (GmABF3). Additionally, the overexpression of GmABF3 exhibited an increased ability to tolerate drought conditions, and it also restored the hypersensitive phenotype of the GmPRR3b overexpressor. Consistently, studies on the manipulation of GmPRR3b gene expression and genome editing in plants revealed contrasting reactions to drought stress. The findings of our study collectively provide compelling evidence that emphasizes the significant contribution of the GmPRR3b-GmABF3 module in enhancing drought tolerance in soybean plants. Moreover, the transcriptional network of GmPRR3b provides valuable insights into the intricate interactions between this gene and the fundamental biological processes associated with plant adaptation to diverse environmental conditions.

Glycine max↗
PubMed2026

OsICL-associated metabolic reprogramming during dehydration in rice is regulated by ABA and modulated by ACC and its metabolites.

Drought coordinates hormonal, transcriptional, and metabolic reprogramming, but how abscisic acid (ABA) and 1-aminocyclopropane-1-carboxylic acid (ACC) jointly shape cereal dehydration responses remains unclear. We integrated hormone profiling, transcriptome and promoter analyses, synthetic promoter assays, and metabolite profiling in rice. ABA and ACC contents increased markedly in rice shoots under moderate soil water deficit. Combined ABA + ACC treatment showed larger absolute overlaps with dehydration-responsive genes than either ABA or ACC treatment alone in shoots; in roots, this pattern was observed for induced but not repressed genes. Promoters of dehydration- and ABA-inducible genes were enriched in ACGT-core motifs, including a CGTACG core preferentially embedded in ACGTACGT, designated the eXtended ACGT box (Xbox). Multimerised Xbox conferred transcriptional induction under soil water deficit and in response to ABA. OsICL was induced under soil water deficit and by ABA or ACC; in shoots, combined ABA + ACC treatment produced the highest mean transcript accumulation. OsICL overexpression and knockout lines showed altered organic-acid, sugar, and amino-acid profiles, particularly under soil water deficit, but several metabolites changed in the same direction in both line classes. These findings support an ABA-centred, ACC-modulated model of dehydration-responsive transcription and associate OsICL regulation with broader, condition-dependent changes in primary metabolism.

Oryza sativa↗