Disease relevance of ABSCISIC ACID

• SKOR expression is strongly inhibited by the stress phytohormone abscisic acid, supporting the hypothesis that control of K+ translocation toward the shoots is part of the plant response to water stress [1].
• Deletion of the Arabidopsis farnesyltransferase gene ERA1 or application of farnesyltransferase inhibitors resulted in ABA hypersensitivity of guard cell anion-channel activation and of stomatal closing [2].
• Disrupting Nt-Syr1 function by cleavage with Clostridium botulinum type C toxin or competition with a soluble fragment of Nt-Syr1 prevents potassium and chloride ion channel response to ABA in guard cells and implicates Nt-Syr1 in an ABA-signaling cascade [3].
• Gibberellic acid (GA) promotes hydrolase production, whereas abscisic acid (ABA), hypoxia, and osmotic stress reduce amylase production [4].
• WCSP1 induction was cold-specific because neither abscisic acid treatment, drought, salinity, nor heat stress induced WCSP1 expression [5].

High impact information on ABSCISIC ACID

• An mRNA cap binding protein, ABH1, modulates early abscisic acid signal transduction in Arabidopsis [6].
• Abscisic-acid-activated protein kinase (AAPK -- found in guard cells, which control stomatal pores -- has been shown to regulate plasma membrane ion channels [7].
• AAPK and AKIP1 are present in the guard-cell nucleus, and in vivo treatment of such cells with abscisic acid enhances the partitioning of AKIP1 into subnuclear foci which are reminiscent of nuclear speckles [7].
• We show that after drought treatment sphingosine-1-phosphate levels increase, and we present evidence that this molecule is involved in the signal-transduction pathway linking the perception of abscisic acid to reductions in guard cell turgor [8].
• A gene induced by the plant hormone abscisic acid in response to water stress encodes a glycine-rich protein [9].

Chemical compound and disease context of ABSCISIC ACID

• Induction of NCED3 (the gene that encodes the rate-limiting enzyme in ABA biosynthesis) by polyethylene glycol-mediated dehydration and ABA accumulation are reduced by this mutation [10].
• This primary defect is responsible for alterations in hormone sensitivity of sax1 plants characterized by the hypersensitivity of root elongation to abscisic acid and auxin and the insensitivity of hypocotyl growth to gibberellins and ethylene (Ephritikhine et al., 1999; Plant J. 18, 303-314) [11].
• Transcript level of CAP2 increased by dehydration and by treatment with sodium chloride, abscisic acid, and auxin, but not by treatment with low temperature, salicylic acid, and jasmonic acid [12].
• The expression of several Arabidopsis thaliana senescence-associated genes (SAGs) in attached and/or detached leaves was compared in response to age, dehydration, darkness, abscisic acid, cytokinin, and ethylene treatments [13].
• Treatments of plants with external stimuli including salicylic acid, jasmonic acid, gibberellic acid and abscisic acid as well as wounding or salt stress did not result in changes in the gene transcription, indicating de novo transcription of Hs1pro-1 upon nematode infection specifically [14].

Biological context of ABSCISIC ACID

• A plant leucine zipper protein that recognizes an abscisic acid response element [15].
• In wild-type Arabidopsis guard cells abscisic acid, oxidative stress, cold, and external calcium elicited cytosolic calcium oscillations of differing amplitudes and frequencies and induced stomatal closure [16].
• An aip2-1-null mutant shows higher ABI3 protein levels compared with wild type after seed stratification, and is hypersensitive to ABA, mimicking the ABI3-overexpression phenotype, whereas AIP2-overexpression plants contain lower levels of ABI3 protein than wild type and are more resistant to ABA, phenocopying abi3 [17].
• Molecular genetic analysis has identified a variety of molecules that are required for correct signaling of the plant hormone abscisic acid (ABA) [18].
• Significant progress has been made in elucidating the mechanism of abscisic acid (ABA)-regulated gene expression, including the characterization of an ABA-responsive element (ABRE), which is regulated by basic domain/Leu zipper transcription factors [19].

Anatomical context of ABSCISIC ACID

• In addition, we have shown that abscisic acid stimulates this phenomenon in chromoplasts, whereas gibberellic acid and auxin delay it [20].
• Gibberellic acid and abscisic acid coordinately regulate cytoplasmic calcium and secretory activity in barley aleurone protoplasts [21].
• The mechanisms by which abscisic acid (ABA) activates the release of K(+)(Rb(+)) from the vacuole of stomatal guard cells, a process essential for ABA-induced stomatal closure, have been investigated by tracer flux measurements [22].
• We suggest that attenuation of the transpiration stream in whole plants is required for the up-regulation of the P(os) of the membranes, and that this up-regulation, which does not require ABA, is mediated by the activation of aquaporins in the plasma membrane [23].
• However, various agents (such as wounding, ethylene, abscisic acid) can cause the microtubules to reorientate by 90 degrees so that they become aligned parallel to the cell's long axis, allowing lateral expansion instead of elongation [24].

Associations of ABSCISIC ACID with other chemical compounds

• The Arabidopsis ABI1 locus is essential for a wide spectrum of abscisic acid (ABA) responses throughout plant development [25].
• The T-DNA-tagged gin6 mutant abrogates the glucose-induced expression of a putative transcription factor, ABI4, previously shown to be involved in seed-specific abscisic acid (ABA) responses [26].
• The Viviparous-1 gene and abscisic acid activate the C1 regulatory gene for anthocyanin biosynthesis during seed maturation in maize [27].
• NADPH oxidase AtrbohD and AtrbohF genes function in ROS-dependent ABA signaling in Arabidopsis [28].
• Antisense suppression of phospholipase D alpha retards abscisic acid- and ethylene-promoted senescence of postharvest Arabidopsis leaves [29].

Gene context of ABSCISIC ACID

• All three responses are affected in the ABA-insensitive mutant abi1 of Arabidopsis thaliana, suggesting that an early step in the signaling of ABA is controlled by the ABI1 locus [30].
• The HAL1 gene and encoded protein are conserved in plants, being induced in these organisms by salt stress and abscisic acid [31].
• The Arabidopsis ABSCISIC ACID-INSENSITIVE2 (ABI2) and ABI1 genes encode homologous protein phosphatases 2C involved in abscisic acid signal transduction [32].
• Arabidopsis OST1 protein kinase mediates the regulation of stomatal aperture by abscisic acid and acts upstream of reactive oxygen species production [33].
• The expression of AtPP2CA (beta-glucuronidase reporter gene) displayed a pattern largely overlapping that of AKT2 and was upregulated by abscisic acid [34].

Analytical, diagnostic and therapeutic context of ABSCISIC ACID

• In response to drought, plants synthesize the hormone abscisic acid, which triggers closing of stomata, thus reducing water loss [35].
• The Viviparous-1 (VP1) transcriptional activator of maize is required for abscisic acid induction of maturation-specific genes late in seed development leading to acquisition of desiccation tolerance and arrest in embryo growth [36].
• Molecular dissection of the gibberellin/abscisic acid signaling pathways by transiently expressed RNA interference in barley aleurone cells [37].
• We report here on the molecular cloning of GLUCOSE INSENSITIVE1 (GIN1) and ABSCISIC ACID DEFICIENT2 (ABA2) which encodes a unique Arabidopsis short-chain dehydrogenase/reductase (SDR1) that functions as a molecular link between nutrient signaling and plant hormone biosynthesis [38].
• In the Arabidopsis alcohol dehydrogenase (Adh) promoter, the G-box regulates expression in response to cold and dehydration, presumably through the action of abscisic acid (ABA), and is bound by a nuclear protein complex in vivo during expression in cell cultures [39].

References