- Abscisic acid
Abscisic acid Identifiers Abbreviations ABA CAS number PubChem ChemSpider EC number MeSH ChEBI ChEMBL RTECS number RZ2475100 Beilstein Reference 2698956 3DMet Jmol-3D images Image 1 Properties Molecular formula C15H20O4 Molar mass 264.32 g mol−1 Appearance Colorless crystals Melting point
186-188 °C, 459-461 K, 367-370 °F
120 °C, 393 K, 248 °F (sublimes)
log P 1.896 Acidity (pKa) 4.868 Basicity (pKb) 9.129 Hazards S-phrases , (what is: /?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Abscisic acid (ABA), also known as abscisin II and dormin, is a plant hormone. ABA functions in many plant developmental processes, including bud dormancy. It is degraded by the enzyme (+)-abscisic acid 8'-hydroxylase.
ABA was originally believed to be involved in abscission. This is now known to be the case only in a small number of plants. ABA-mediated signalling also plays an important part in plant responses to environmental stress and plant pathogens. The plant genes for ABA biosynthesis and sequence of the pathway have been elucidated. ABA is also produced by some plant pathogenic fungi via a biosynthetic route different from ABA biosynthesis in plants.
Abscisic acid owes its names to its role in the abscission of plant leaves. In preparation for winter, ABA is produced in terminal buds. This slows plant growth and directs leaf primordia to develop scales to protect the dormant buds during the cold season. ABA also inhibits the division of cells in the vascular cambium, adjusting to cold conditions in the winter by suspending primary and secondary growth.
Abscisic acid is also produced in the roots in response to decreased soil water potential and other situations in which the plant may be under stress. ABA then translocates to the leaves, where it rapidly alters the osmotic potential of stomatal guard cells, causing them to shrink and stomata to close. The ABA-induced stomatal closure reduces transpiration, thus preventing further water loss from the leaves in times of low water availability.
Several ABA-mutant Arabidopsis thaliana plants have been identified by the Nottingham Arabidopsis Stock Centre - both those deficient in ABA production and those with altered sensitivity to its action. Plants that are hypersensitive or insensitive to ABA show phenotypes in seed dormancy, germination, stomatal regulation, and some mutants show stunted growth and brown/yellow leaves. These mutants reflect the importance of ABA in seed germination and early embryo development.
Pyrabactin (a pyridyl containing ABA activator) is a naphthalene sulfonamide hypocotyl cell expansion inhibitor, which is an agonist of the seed ABA signaling pathway. It is the first agonist of the ABA pathway that is not structurally related to ABA.
ABA has recently been shown to elicit potent anti-inflammatory and anti-diabetic effects in mouse models of diabetes/obesity, inflammatory bowel disease, atherosclerosis and influenza infection. In mammalian cells ABA targets a protein known as lanthionine synthetase C-like 2 (LANCL2), triggering an alternative mechanism of activation of peroxisome proliferator-activated receptor gamma (PPAR gamma).
Abscisic acid (ABA) is an isoprenoid plant hormone, which is synthesized in the plastidal 2-C-methyl-D-erythritol-4-phosphate (MEP) pathway; unlike the structurally related sesquiterpenes, which are formed from the mevalonic acid-derived precursor farnesyl diphosphate (FDP), the C15 backbone of ABA is formed after cleavage of C40 carotenoids in MEP. Zeaxanthin is the first committed ABA precursor; a series of enzyme-catalyzed epoxidations and isomerizations via violaxanthin, and final cleavage of the C40 carotenoid by a dioxygenation reaction yields the proximal ABA precursor, xanthoxin, which is then further oxidized to ABA.
Abamine has been designed, synthesized, developed and then patented as the first specific ABA biosynthesis inhibitor, which makes it possible to regulate endogenous level of ABA. 
Location and timing of ABA biosynthesis
- Released during desiccation of the vegetative tissues and when roots encounter soil compaction.
- Synthesized in green fruits at the beginning of the winter period
- Synthesized in maturing seeds, establishing dormancy
- Mobile within the leaf and can be rapidly translocated from the roots to the leaves by the transpiration stream in the xylem
- Produced in response to environmental stress, such as heat stress, water stress, salt stress
- Synthesized in all plant parts, e.g., roots, flowers, leaves and stems
- Antitranspirant - Induces stomatal closure, decreasing transpiration to prevent water loss.
- Inhibits fruit ripening
- Responsible for seed dormancy by inhibiting cell growth – inhibits seed germination
- Inhibits the synthesis of Kinetin nucleotide 
- Downregulates enzymes needed for photosynthesis.
- ^ "Abscisic Acid - Compound Summary". PubChem Compound. USA: National Center for Biotechnology Information. 16 September 2004. Identification and Related Records. http://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?cid=5280896&loc=ec_rcs. Retrieved 22 October 2011.
- ^ Zhu, Jian-Kang (2002). "Salt and Drought Stress Signal Transduction in Plants". Annual Review of Plant Biology 53: 247–73. doi:10.1146/annurev.arplant.53.091401.143329. PMC 3128348. PMID 12221975. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3128348.
- ^ Seo, M; Koshiba, T (2002). "Complex regulation of ABA biosynthesis in plants". Trends in Plant Science 7 (1): 41–8. doi:10.1016/S1360-1385(01)02187-2. PMID 11804826.
- ^ a b Nambara, Eiji; Marion-Poll, Annie (2005). "Abscisic Acid Biosynthesis and Catabolism". Annual Review of Plant Biology 56: 165–85. doi:10.1146/annurev.arplant.56.032604.144046. PMID 15862093.
- ^ Milborrow, B.V. (2001). "The pathway of biosynthesis of abscisic acid in vascular plants: A review of the present state of knowledge of ABA biosynthesis". Journal of Experimental Botany 52 (359): 1145–64. doi:10.1093/jexbot/52.359.1145. PMID 11432933.
- ^ Siewers, V.; Smedsgaard, J.; Tudzynski, P. (2004). "The P450 Monooxygenase BcABA1 is Essential for Abscisic Acid Biosynthesis in Botrytis cinerea". Applied and Environmental Microbiology 70 (7): 3868–76. doi:10.1128/AEM.70.7.3868-3876.2004. PMC 444755. PMID 15240257. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=444755.
- ^ Bassaganya-Riera, J; Skoneczka, J; Kingston, DG; Krishnan, A; Misyak, SA; Guri, AJ; Pereira, A; Carter, AB et al. (2010). "Mechanisms of action and medicinal applications of abscisic Acid". Current medicinal chemistry 17 (5): 467–78. doi:10.2174/092986710790226110. PMID 20015036. http://www.benthamdirect.org/pages/content.php?CMC/2010/00000017/00000005/0006C.SGM.
- ^ Bassaganya-Riera, J.; Guri, A. J.; Lu, P.; Climent, M.; Carbo, A.; Sobral, B. W.; Horne, W. T.; Lewis, S. N. et al. (2010). "Abscisic Acid Regulates Inflammation via Ligand-binding Domain-independent Activation of Peroxisome Proliferator-activated Receptor". Journal of Biological Chemistry 286 (4): 2504–16. doi:10.1074/jbc.M110.160077. PMC 3024745. PMID 21088297. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3024745.
- ^ Abscisic acid biosynthesis inhibitor, Shigeo Yoshida et al US 7098365
- ^ DeJong-Hughes, J., et al. (2001) Soil Compaction: causes, effects and control. University of Minnesota extension service
- ^ Zhang, Jianhua; Schurr, U.; Davies, W. J. (1987). "Control of Stomatal Behaviour by Abscisic Acid which Apparently Originates in the Roots". Journal of Experimental Botany 38 (7): 1174. doi:10.1093/jxb/38.7.1174.
- ^ Miernyk, J. A. (1979). "Abscisic Acid Inhibition of Kinetin Nucleotide Formation in Germinating Lettuce Seeds". Physiologia Plantarum 45: 63–6. doi:10.1111/j.1399-3054.1979.tb01664.x.
- ^ Chandler, P M; Robertson, M (1994). "Gene Expression Regulated by Abscisic Acid and its Relation to Stress Tolerance". Annual Review of Plant Physiology and Plant Molecular Biology 45: 113–41. doi:10.1146/annurev.pp.45.060194.000553.
Wikimedia Foundation. 2010.
Look at other dictionaries:
abscisic acid — [ab sis′ik, absiz′ik] n. an organic acid, C15H20O4, which acts as a growth regulator causing dormancy and abscission of leaves and fruit: sometimes called abscisin [ab sis′in, absiz′in] … English World dictionary
abscisic acid — abscisic acid. См. абсцизовая кислота. (Источник: «Англо русский толковый словарь генетических терминов». Арефьев В.А., Лисовенко Л.А., Москва: Изд во ВНИРО, 1995 г.) … Молекулярная биология и генетика. Толковый словарь.
abscisic acid — abscizo rūgštis statusas T sritis chemija apibrėžtis Izoprenoidinis fitohormonas. formulė (CH₃)₃(O=)C₆H₃(OH)CH=CHC(CH₃)=CHCOOH atitikmenys: angl. abscisic acid; dormin rus. абсцизиновая кислота; дормин ryšiai: sinonimas – dorminas sinonimas – (S) … Chemijos terminų aiškinamasis žodynas
abscisic acid — noun Etymology: abscision (variant of abscission) + ic Date: 1968 a plant hormone C15H20O4 that is a sesquiterpene widespread in nature and that typically promotes leaf abscission and dormancy and has an inhibitory effect on cell elongation … New Collegiate Dictionary
abscisic acid — A growth inhibiting plant hormone found in vascular plants. Originally believed to be important in abscission (leaf fall), now known to be involved in a number of growth and developmental processes in plants, including, in some circumstances,… … Dictionary of molecular biology
abscisic acid — /ab sis ik, siz /, Biochem. a growth regulating plant hormone, C15H20O4, that promotes dormancy and the aging and abscission of leaves. [ABSCIS(SION) + IC, on the model of the earlier name abscisin (see IN2), coined in 1961] * * * … Universalium
abscisic acid — noun A terpenoid plant hormone that inhibits seed germination; once thought to be important in abscission … Wiktionary
abscisic acid — [ab sɪsɪk] noun Biochemistry a plant hormone which promotes leaf detachment, induces seed and bud dormancy, and inhibits germination. Origin 1960s: from abscission … English new terms dictionary
abscisic acid — A phytohormone implicated in the control of many plant responses to abiotic stress, such as extent of stomatal opening under water deficit (i.e. drought) conditions … Glossary of Biotechnology
abscisic acid — n. a plant hormone which promotes leaf detachment and bud dormancy and inhibits germination. Etymology: L abscis past part. stem of abscindere (as AB , scindere to cut) … Useful english dictionary