Abscisic acid, better known by its acronym ABA, is one of the five major plant hormones that orchestrate plant life. This phytohormone plays a crucial role in plant adaptation to adverse environmental conditions, such as drought, cold, soil salinity, or pathogen attacks. Beyond its fundamental importance in plant physiology, ABA is attracting increasing interest in numerous industrial sectors: agriculture, biotechnology, biostimulant formulation, nutraceuticals, and cosmetics. Its precise analysis in the laboratory has become a major challenge for ensuring the quality and conformity of derived products. In this article, we will explore in detail the chemical characteristics of abscisic acid, its essential biological roles, its biosynthetic pathways, its industrial applications, and the analytical techniques that allow for its rigorous quantification in plant matrices.
Table of Contents
What is abscisic acid? Definition and chemical characteristics
Definition and identification of ABA
Abscisic acid (ABA ) is a natural phytohormone found in most photosynthetic organisms. Identified as CAS number 21293-29-8 for its biologically active form (+) and as CAS number 14375-45-2 in some commercial references, ABA also has several synonyms inherited from its scientific history: dormin, abscisine II, or ABK. Its ECHA number is 100.040.275 and its EC number is 244-319-5.
This hormone is widespread in the plant kingdom. It is found not only in vascular plants, but also in mosses, algae, fungi, and cyanobacteria. Conversely, it is absent in most bacteria, archaea, and liverworts. This distribution suggests a very early appearance in evolution, probably linked to the colonization of terrestrial environments by photosynthetic organisms and the need to adapt to variations in water availability.
Within the plant, ABA is primarily synthesized in the tissues of mature roots and leaves, but it can be produced in almost all vegetative organs in response to various environmental signals. Its tissue concentration varies considerably depending on the conditions: it can increase tenfold to fiftyfold during severe water stress, making it a true biochemical marker of the stress response.
Chemical structure and physical properties
From a chemical standpoint, abscisic acid belongs to the sesquiterpenoid family, compounds with 15 carbon atoms derived from isoprene. Its molecular formula is C₁₅H₂₀O₄ and its molar mass is 264.32 g/mol. The elemental composition of the molecule is as follows: 68.16% carbon, 7.63% hydrogen, and 24.21% oxygen.
The structure of ABA is characterized by a substituted cyclohexene ring, bearing a ketone function and a hydroxyl group, conjugated to a dienoid side chain terminating in a carboxylic acid function. This molecular architecture confers unique properties for interacting with its PYR/PYL family protein receptors, which in turn modulate the activity of type 2C phosphatases (PP2C) responsible for hormonal signal transduction.
Physically, abscisic acid is a yellowish powder with a melting point between 160 °C and 188 °C, depending on its purity and isomer. Its sublimation temperature is approximately 120 °C. The molecule crystallizes in the monoclinic system, space group P21/c, with a lattice volume of 1428 ų.
ABA is a weak acid, with a pKa of approximately 4.7. This acid-base property is essential for understanding its distribution within the plant: depending on the pH of the cellular compartment, ABA can exist in its protonated form (capable of crossing lipid membranes) or in its ionized form (trapped in alkaline compartments such as the chloroplast stroma). This characteristic largely explains the absence of a known specific transport system for this hormone, whose migration is essentially governed by its ionization state and by mass fluxes in the phloem and xylem.
A brief history of the discovery
The story of the discovery of abscisic acid perfectly illustrates the convergence of several independent lines of research. As early as the 1940s, Torsten Hemberg, a researcher at Stockholm University, demonstrated a positive correlation between the period of vegetative dormancy and the presence of an ether-soluble growth inhibitor in potato tubers. This pioneering observation, published in 1949 in Physiologia Plantarum, paved the way for the identification of a new class of negative growth regulators.
In the following years, several teams used paper chromatography and bioassays based on the growth of oat coleoptiles to isolate growth-inhibiting compounds. For example, a substance called dormin was purified from sycamore leaves harvested in early autumn, when the trees enter dormancy.
Meanwhile, in 1963, Frederick T. Addicott and Larry A. Davis in the United States studied the compounds responsible for the abscission (dropping) of cotton fruits. They isolated two substances which they named abscisin I and abscisin II. When it became apparent that dormin and abscisin II were chemically identical, the compound was renamed abscisic acid to reflect its presumed involvement in the abscission process.
Ironically, we now know that ABA's role in abscission is actually limited to a small number of plant species. In most plants, the hormone promotes tissue senescence rather than true abscission. Nevertheless, its name remains universally used. Since this discovery, ABA has been the subject of thousands of scientific publications, and its understanding took a major leap forward in 2009 with the identification of PYR/PYL receptors by Sang-Youl Park's team, published in the journal Science. This breakthrough largely elucidated the cellular signaling cascade activated by this fundamental hormone.
What are the biological roles of abscisic acid?
Abscisic acid is often called the "stress hormone" because of its central role in plant adaptive mechanisms in response to environmental stresses. However, its functions extend far beyond simply responding to stress: ABA plays a role in embryonic development, dormancy, root growth regulation, senescence, and even defense against pathogens. Let's examine in detail the main physiological functions of this versatile phytohormone.
Regulation of seed and bud dormancy
Regulating dormancy is one of the most emblematic functions of abscisic acid. This hormone plays a crucial role in maintaining the quiescence of seeds and buds, preventing their premature awakening under unfavorable environmental conditions.
During seed maturation, ABA accumulates in embryonic tissues, where it induces the expression of numerous specific genes, notably those encoding LEA (Late Embryogenesis Abundant) proteins. These proteins protect cellular structures from dehydration during the final desiccation phase of the seed, which can reach a residual water content of only 5 to 10%. ABA thus allows the seed to survive in a state of dormancy for months, or even years, before germinating under favorable conditions.
The inhibition of germination by ABA acts in direct antagonism with gibberellin (GA), another phytohormone that, conversely, stimulates germination. The ABA/GA ratio constitutes a true molecular switch: a high ratio maintains dormancy, while a low ratio triggers dormancy breaking. This mechanism explains why many seeds require a period of cold stratification (which degrades ABA) before they can germinate.
In woody species of temperate regions, ABA is also produced in large quantities in terminal buds during the autumn. This hormonal production slows plant growth and directs leaf primordia toward the formation of protective scales. Simultaneously, ABA inhibits cell division in the vascular cambium, thus suspending primary and secondary growth during the cold season. In the spring, the gradual breakdown of ABA, combined with increased gibberellin levels, allows growth to resume.
Response to water stress and stomatal closure
The closure of stomata in response to water deficit is arguably the best-characterized function of abscisic acid. When soil water potential decreases, roots quickly detect this drop and synthesize ABA, which is then transported via the xylem to the leaves.
At the leaf level, ABA acts on the guard cells of the stomata, the microscopic openings that allow gas exchange between the plant and the atmosphere. The hormone rapidly alters the osmotic potential of these cells, causing the efflux of potassium ions (K⁺) and anions, followed by water release. The guard cells then retract, closing the stomatal opening and thus limiting water loss through transpiration. This phenomenon can occur within minutes of stress perception, demonstrating the extraordinary speed of action of this hormone.
A close linear correlation has been established between ABA content in leaves and stomatal conductance, measured per unit leaf area. This quantitative relationship allows ABA to be used as a biochemical indicator of water stress in plants, which is of major interest in agronomy for the selection of drought-tolerant varieties.
Beyond water stress, ABA plays a role in responding to many other environmental constraints:
- Cold and freeze tolerance : ABA induces the accumulation of cryoprotective proteins and compatible solutes (proline, soluble sugars) which lower the cellular freezing point.
- Salt stress : in the presence of high concentrations of sodium in the soil, ABA activates mechanisms of ion compartmentalization and osmolyte synthesis.
- Heat stress : the hormone participates in the induction of heat shock proteins (HSPs) which protect cellular structures.
- Heavy metal tolerance : ABA modulates the absorption and sequestration of toxic ions such as cadmium or aluminum.
Regulation of root development: a recent discovery
A major scientific breakthrough published in November 2022 in the journal Science by Mehra and colleagues revealed a new role for abscisic acid in regulating the development of secondary (or lateral) roots. This study shed molecular light on a long-observed phenomenon: the absence of root branching in dry soil zones.
When a main root grows through a heterogeneous area of soil, alternating between wet and dry regions, it only forms secondary roots in sufficiently moist areas. This phenomenon, called xerobranching , allows the plant to optimize its resources by avoiding investing in root development in areas where water is unavailable.
Using an in vitro root culture system and the ABACUS2, which allows visualization of ABA distribution in real time in plant tissues, researchers have highlighted the following molecular mechanism:
- In dry conditions, the flow of water in the root reverses: water flows out of the root into the soil by osmosis. This centrifugal flow carries ABA from the central vascular tissues to the periphery of the root. ABA then induces the production of callose, a polysaccharide that blocks plasmodesmata, the microscopic channels that allow communication between neighboring cells. The transport of (auxin the hormone responsible for initiating secondary roots) to the pericycle is thus blocked, preventing the formation of new roots.
- In humid conditions, water normally flows into the root, carrying ABA to the central vascular elements. The plasmodesmata remain open, allowing auxin to reach the pericycle and induce the formation of secondary roots.
This discovery perfectly illustrates theantagonism between abscisic acid and auxin in the regulation of plant development, and highlights the sophistication of the mechanisms by which plants adapt their architecture to the heterogeneity of their environment. These advances open up promising perspectives for the selection of cultivated varieties that perform better under drought conditions.
Other physiological functions of ABA
Beyond its primary roles, abscisic acid is involved in numerous other physiological processes in plants:
- Senescence of vegetative organs : ABA accelerates the natural aging of leaves, promoting the remobilization of nutrients (nitrogen, phosphorus) towards young growing organs or storage organs.
- Defense against pathogens : ABA participates in the rapid closure of stomata in response to the perception of pathogen-associated molecular patterns (PAMPs), thus preventing their penetration into leaf tissues. The hormone also establishes a complex cross-talk with the jasmonic acid and ethylene signaling pathways , which orchestrate plant immune responses.
- Inhibition of internodal elongation : ABA contributes to maintaining a compact architecture in plants under stress, limiting investment in vertical growth.
- Regulation of flowering : under certain conditions, ABA can reverse the photoperiodic requirements necessary for flowering, illustrating the complexity of its interactions with other endogenous signals.
- Dry fruit drop : in some species, ABA does indeed participate in the abscission processes of mature fruits, in accordance with its historical name.
This functional versatility makes abscisic acid one of the most studied and strategic plant hormones for understanding and improving crop performance in a context of climate change.
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How is abscisic acid biosynthesized and inactivated in plants?
Understanding the biosynthesis and inactivation pathways of abscisic acid is a fundamental challenge for research in plant physiology and for the development of innovative agricultural products. These metabolic pathways, gradually elucidated over the last two decades, reveal a fine and complex regulation that allows plants to precisely adjust their hormone levels according to environmental conditions.
ABA biosynthesis pathway in plants
In vascular plants, abscisic acid biosynthesis occurs primarily in the parenchyma of roots and mature leaves, within specialized organelles called plastids. This subcellular localization is explained by the fact that ABA is derived from the metabolism of carotenoids, which are themselves synthesized in plastids (chloroplasts in green organs, chromoplasts in non-photosynthetic organs).
The ABA biosynthesis pathway is called indirect because it does not proceed directly from C15 sesquiterpene precursors, but rather involves the oxidative cleavage of C40 carotenoid precursors. This pathway comprises several successive steps:
- Step 1: Synthesis of 1-deoxy-D-xylulose-5-phosphate (DOXP). This 5-carbon molecule is produced from pyruvate and glyceraldehyde-3-phosphate via the methylerythritol phosphate (MEP) pathway, which is specific to plant plastids. DOXP is the entry point for the production of plastid isoprenoids.
- Step 2: Conversion of DOXP to isopentenyl pyrophosphate (IPP). IPP, a basic 5-carbon unit, is then polymerized to form chains of increasing length.
- Step 3: Carotenoid formation. The condensation of several IPP units leads to the synthesis of C40 carotenoids, including β-carotene, zeaxanthin and violaxanthin.
- Step 4: Production of 9′-cis-neoxanthin (C40). This xanthophyll is the direct precursor of the ABA pathway. An alternative pathway involves cis-violaxanthin as an intermediate.
- Step 5: Oxidative cleavage by NCED enzymes. 9′-cis-neoxanthine is cleaved by 9-cis-epoxycarotenoid dioxygenase (NCED) enzymes, which constitute the rate-limiting and highly regulated step of the pathway. This cleavage produces xanthoxine, a C15 molecule that represents the first 15-carbon intermediate of the pathway.
- Step 6: Conversion to abscisic aldehyde. Xanthoxine is converted to ABA-aldehyde (abscisic aldehyde) by a short-chain dehydrogenase enzyme in the cytosol.
- Step 7: Final oxidation to abscisic acid . ABA-aldehyde is finally oxidized to abscisic acid by a molybdenum-dependent aldehyde oxidase (AAO3 in Arabidopsis ).
The expression of genes encoding enzymes in this pathway, particularly NCED, is strongly induced by environmental stresses. Under water deficit conditions, NCED3 in Arabidopsis thalianacan increase 50- to 100-fold within a few hours, enabling rapid and massive ABA production. This transcriptional regulation constitutes the main mechanism for adjusting hormone levels in response to stress.
It is interesting to note that some phytopathogenic fungi , such as Botrytis cinerea , are also capable of producing abscisic acid, but via a completely different biosynthetic pathway, starting directly from farnesyl pyrophosphate (the direct C15 pathway). This alternative pathway involves a cytochrome P450 monooxygenase -like enzyme (BcABA1). Fungal production of ABA could constitute a strategy for the pathogen to manipulate plant defenses, illustrating the complexity of plant-microorganism interactions.
ABA inactivation mechanisms and catabolism
Abscisic acid is a relatively unstable in plant tissues, and its concentration is regulated not only by its biosynthesis but also by active inactivation and degradation mechanisms. This dual regulation allows plants to rapidly adjust their hormone levels, particularly when stress conditions disappear.
Two major pathways of ABA inactivation have been characterized:
- Sugar conjugation pathway : ABA can be conjugated to a sugar, glucose, to formABA-β-D-glucose ester (ABA-GE). This reaction, catalyzed by glucosyltransferases, leads to an inactive form of the hormone. ABA-GE can accumulate in the vacuole where it serves as a readily available reserve, or be exported to other tissues. This conjugation can be reversible (release of active ABA by β-glucosidases during stress) or lead to irreversible inactivation.
- Oxidation pathway : ABA can be hydroxylated at the 8′ position by enzymes of the cytochrome P450 CYP707A family , leading to the formation of 8′-hydroxy-ABA , an unstable intermediate that spontaneously cyclizes to phaseic acid (PA) . Phaseic acid can then be reduced to 4′-dihydrophaseic acid (DPA) , considered the terminal catabolic form of ABA. CYP707A genes are notably induced during dormancy release and upon the return to favorable hydration conditions.
The half-life of ABA in plant tissues is generally short, on the order of a few hours, which allows for dynamic and adaptive hormonal signaling.
ABA cellular transport and perception
Unlike other plant hormones such as auxin, which has specialized transporters (PIN, AUX1), no major specific transport system for ABA has yet been identified. However, several ABC (ATP-Binding Cassette) transporters, such as ABCG25 and ABCG40 in Arabidopsis, have been described as capable of transporting ABA across cell membranes.
The distribution of ABA in the plant is largely governed by its weak acid property (pKa = 4.7). Depending on the pH of the cellular compartments, ABA can exist in two forms:
- In protonated form (ABAH), in acidic environments such as the apoplasm or xylem (pH ~5.5-6), it is lipophilic and can freely cross lipid membranes.
- In ionized form (ABA⁻), in alkaline environments such as the cytosol (pH ~7.2) or the chloroplast stroma (pH ~8), it is hydrophilic and remains trapped in the compartment.
This ion-trapping phenomenon partly explains how ABA preferentially accumulates in certain compartments depending on physiological conditions. Under stress, xylem alkalinization alters the distribution of ABA and promotes its arrival at the guard cells in the stomata.
Long-distance transport of ABA occurs in a non-polarized : via the phloem in leaves and via the xylem in roots, accompanying sap flow. Migration time is relatively short due to the hormone's rapid metabolism.
Cellular perception of ABA saw a major advance in 2009 with the discovery of PYR/PYL/RCAR (Pyrabactin Resistance/PYR-Like/Regulatory Component of ABA Receptor) receptors by Sang-Youl Park's team, published in Science . These soluble receptors, present in the cytosol and nucleus, bind ABA and inhibit the activity of type 2C phosphatases (PP2Cs) such as ABI1 and ABI2. In the absence of ABA, PP2Cs constitutively inhibit kinases of the SnRK2 (SNF1-Related Kinase 2) family. In the presence of ABA, PP2Cs are inhibited, releasing SnRK2s, which can then phosphorylate numerous substrates: transcription factors (ABF/AREB), ion channels in guard cells, and metabolic enzymes. This signaling cascade, now well characterized, constitutes the molecular core of the response to ABA in plants.
The identification of pyrabactin, a pyridyl naphthalene sulfonamide compound, as the first synthetic ABA pathway agonist not structurally related to the hormone, paved the way for the development of biotechnological molecules mimicking the effects of ABA, with potential applications in agriculture to improve crop stress tolerance.
What are the industrial applications of abscisic acid?
The knowledge accumulated on abscisic acid over the past few decades has paved the way for numerous industrial applications, particularly in sectors where plant performance or the valorization of plant extracts represent major economic stakes. From precision agriculture to high-end cosmetics, including nutraceuticals and plant biotechnology, ABA is the subject of growing interest, resulting in the development of innovative products and the emergence of new markets.
Applications in agriculture and plant protection
The agricultural sector undoubtedly represents the main industrial market for abscisic acid. Faced with the challenges posed by climate change, the increasing frequency of drought episodes, and soil degradation, improving crop resilience to abiotic stresses has become a strategic priority for agri-food stakeholders.
ABA is notably used in the formulation of biostimulants, a category of plant protection products that do not replace fertilizers or pesticides, but improve the efficiency of plant physiological processes. According to European Regulation 2019/1009, which came into force in July 2022, plant biostimulants are defined as products that stimulate plant nutrition processes, regardless of their nutrient content, with the aim of improving one or more characteristics: nutrient use efficiency, tolerance to abiotic stress, quality of harvested products, or nutrient availability in the rhizosphere.
In this context, ABA and its synthetic analogues are used for:
- Improving drought tolerance : Foliar application of ABA or mimetic molecules induces the preventive closure of stomata before the plant experiences severe water stress, thus conserving available water. Studies have shown that applying ABA analogs can reduce yield losses by 20 to 40% under water stress conditions.
- Synchronizing fruit ripening : In grapevines, the application of exogenous ABA is used commercially to homogenize the color and ripening of berries, particularly in red grape varieties where natural ABA production may be insufficient. The best-known commercial product, ProTone® SG (pure ABA), has been authorized in several wine-producing countries since the 2010s.
- Controlling plant dormancy : in nurseries and horticulture, ABA allows artificially extending plant dormancy to facilitate storage and transport, or conversely, lifting it in a controlled manner.
- Improving resistance to cold and frost : preventive application of ABA induces the accumulation of protective osmolytes in plant tissues, increasing their tolerance to negative temperatures.
The development of stress-resistant cultivated varieties is also a major focus of applied research. A thorough understanding of ABA biosynthesis and signaling pathways allows for the identification of candidate genes for marker-assisted breeding programs or for transgenesis and genome editing approaches (CRISPR-Cas9).
Applications in plant research and biotechnology
Beyond its direct agronomic applications, abscisic acid is a fundamental research tool widely used in plant physiology, genetics, and molecular biology laboratories. Studies on ABA constitute a dynamic research area, with several thousand scientific publications each year.
The main uses of ABA in research include:
- The study of stress response mechanisms : ABA serves as a biochemical marker to quantify the intensity of stress perceived by the plant. Measuring endogenous ABA, coupled with analyzing the expression of target genes, allows for a detailed characterization of physiological responses.
- Characterization of mutants : Numerous Arabidopsis thaliana lines with mutations in ABA pathway genes ( biosynthesis-deficient aba1 , aba2 , and aba3 mutants, or abi1 to abi5 mutants affected in signaling) are available in international collections such as the Nottingham Arabidopsis Stock Centre (NASC) . These genetic resources allow for the exploration of the precise functions of each component of the hormonal pathway.
- The development of biosensors : recent advances in synthetic biology have led to the design of fluorescent biosensors such as ABACUS2, which visualize the spatial and temporal distribution of ABA in plant tissues in real time. These tools notably enabled the discovery of the xerobranching mechanism, published in 2022.
- Variety selection programs : breeders are now integrating knowledge of the ABA pathway to select varieties with a better compromise between productivity and stress tolerance, a major challenge in a context of water scarcity.
Applications in nutraceuticals and food supplements
The nutraceutical industry is showing increasing interest in abscisic acid due to its potential bioactive properties in mammals. Several recent studies have suggested that ABA, present in certain plant-based foods, could modulate carbohydrate metabolism and the inflammatory response in humans.
ABA is naturally present in many plant-based foods, including:
- Red fruits ( blueberries, raspberries, blackcurrants), whose concentrations can reach 5 to 50 µg/g of fresh matter.
- Citrus fruits (oranges, grapefruits), particularly the peel and membranes.
- Leafy vegetables ( spinach, lettuce).
- Legumes (beans, lentils) .
- Some medicinal plants used in traditional herbal medicine.
Accurate analysis of ABA content in these food matrices is therefore a key issue for quality and traceability for manufacturers of food supplements andstandardized plant extracts. Furthermore, nutritional and health claims associated with these products must be validated in accordance with applicable European regulations, in particular Regulation (EC) No 1924/2006 on nutrition and health claims.
Applications in cosmetics and formulation of natural products
The cosmetics industry, undergoing a major shift towards more natural and sustainable formulations, is also interested in plant extracts containing abscisic acid. Several interesting properties have been identified for use in cosmetic :
- Protective effect against cutaneous oxidative stress : some in vitro studies suggest that ABA could participate in the protection of skin cells against free radicals generated by UV or air pollution.
- Modulation of skin hydration : by analogy with its role in regulating plant transpiration, ABA is being studied for its potential effects on skin hydration mechanisms.
- Valorization of natural assets : plant extracts rich in ABA, in particular extracts of algae or plants adapted to arid environments, are valued as active ingredients in anti-aging, moisturizing or repairing formulations.
For these applications, quality control of raw materials is crucial. Cosmetic manufacturers must guarantee that the concentrations of ABA and other bioactive compounds conform to the stated specifications and that the products comply with EC Regulation 1223/2009 on cosmetic products. This implies precise measurement of ABA in the plant extracts used, as well as monitoring the stability of these compounds over time and under different storage conditions.
How to analyze abscisic acid in the laboratory?
The precise determination of abscisic acid (ABA) in plant matrices and derived products is a major analytical challenge, at the intersection of analytical chemistry, plant biochemistry, and industrial quality control. Since natural ABA concentrations in plant tissues are often very low (on the order of nanograms to micrograms per gram of fresh material), the analytical methods used must combine sensitivity, specificity, and reproducibility. Advances in analytical techniques over the last two decades have significantly improved the accuracy and reliability of these determinations, enabling manufacturers to meet the most stringent regulatory requirements.
Procedures and techniques for the analysis of abscisic acid
Several analytical techniques are currently available to quantify ABA in various matrices: plant extracts, biostimulants, dietary supplements, cosmetics, or plant protection products. The choice of method depends on the matrix to be analyzed, the required sensitivity, the number of samples to be processed, and economic constraints.
- Liquid chromatography coupled with mass spectrometry (LC-MS and LC-MS/MS) is currently the reference method for ABA quantification. This technique combines the chromatographic separation of compounds in the liquid phase with detection by mass spectrometry, allowing both the precise identification of the analyte (via its molecular mass and fragmentation spectrum) and its quantification. LC-MS/MS, or liquid chromatography coupled with tandem mass spectrometry, achieves limits of quantification (LOQs) on the order of 0.1 to 1 mg/kg in complex plant matrices and can reach levels as low as a few picograms per milliliter under optimized conditions. This exceptional sensitivity is essential for quantifying the low concentrations of endogenous ABA in plant tissues.
- High-performance liquid chromatography (HPLC) : coupled with a UV detector (generally at 254 or 265 nm, the wavelengths of maximum absorption of ABA), this method is widely used for the quantification of ABA in concentrated plant extracts and biostimulants. More accessible than LC-MS/MS, it is nevertheless less sensitive and less specific, particularly in the presence of complex matrices containing interfering compounds.
- Immunological methods (ELISA) : ELISA (Enzyme-Linked Immunosorbent Assay) tests rely on the use of ABA-specific antibodies. They offer high sensitivity (LOQ on the order of picograms) and allow for the parallel analysis of numerous samples. These methods are particularly well-suited to research laboratories processing large sample volumes, but their specificity can be limited by cross-reactions with structurally similar metabolites such as phaseic acid.
- Gas chromatography-mass spectrometry (GC-MS) : an older technique, it requires a preliminary chemical derivatization step (methylation) to make ABA sufficiently volatile. It offers excellent specificity but is gradually being replaced by LC-MS methods, which are simpler to implement.
- Fluorescent biosensors (ABACUS2, nlsABACUS2) : These innovative tools, developed for research purposes, allow the in vivo of the spatial and temporal distribution of ABA in living plant tissues. They are not used for the quantitative measurement of commercial products, but constitute valuable tools for basic research.
Theextraction is a critical step in any quantitative ABA analysis. Extraction protocols generally use organic solvents (methanol, isopropanol, acidified hydroalcoholic mixtures), sometimes combined with solid-phase extraction (SPE) purification steps to remove interfering compounds. The use ofdeuterated internal standards (notably D6-ABA) allows for the correction of losses during extraction and significantly improves the accuracy of the results.
Importance of regulatory compliance testing (ISO 17025 standards, COFRAC)
Abscisic acid analyses performed in an industrial or regulatory context must be carried out in accredited laboratories, guaranteeing the reliability, traceability, and legal validity of the results. Several standards and accreditations govern this activity.
ISO 17025 is the international standard that establishes the general requirements for the competence of calibration and testing laboratories. It covers all aspects of a laboratory's activities: personnel qualifications, validation of analytical methods, metrological traceability, management of measurement uncertainties, quality control, and documentation systems. An ISO 17025 accredited laboratory guarantees that its results are produced according to rigorous and internationally recognized procedures.
In France, accreditation is granted by COFRAC (French Accreditation Committee), the only national accreditation body recognized by the French State. COFRAC accreditation for abscisic acid analysis involves periodic evaluation of the laboratory by expert auditors, guaranteeing the maintenance of a high level of technical and organizational quality.
For ABA analyses, compliance testing is essential in several contexts:
- Ensuring the safety of biostimulants and fertilizers : In accordance with European Regulation 2019/1009, fertilizer products marketed in the European Union must meet strict compositional specifications. Measuring ABA in biostimulants allows verification of compliance with the levels declared on the label and detection of potential contamination.
- Validating plant extracts in food supplements : Manufacturers of food supplements based on plant extracts must precisely characterize the composition of their products, particularly in terms of bioactive compounds such as ABA. This characterization is essential to support nutritional claims and guarantee consumer safety.
- Ensuring the compliance of cosmetic products : according to EC Regulation 1223/2009, cosmetic products placed on the European market must have a Product Information File (PIF) including the characterization of raw materials. The analysis of ABA in plant extracts used in cosmetics contributes to this characterization.
- Validating research programs : for manufacturers investing in the development of new products, reliable and reproducible analyses are essential to validate the effectiveness of formulations and guide technical choices.
Quality control of plant matrices and derived products
Quality control of abscisic acid in industrial matrices involves a set of parameters that go beyond simple quantitative analysis. A complete analysis typically includes:
- The identification of ABA by comparison with a certified reference standard, validating the exact nature of the detected compound.
- The precise quantification of the ABA content in the matrix, expressed in mg/kg of dry matter or in mg/L for liquid solutions.
- Characterization of isomers : ABA has several stereoisomeric forms (notably the biologically active (+)-cis-trans form and the inactive (–) form), and only the active form is of biological interest. Separating these isomers requires specific chiral chromatographic methods.
- Detection of degradation products : the presence ofphaseic acid or4′-dihydrophaseic acid may indicate ABA degradation during storage or the manufacturing process, and must be monitored to ensure the stability of the finished product.
- The search for associated contaminants : depending on the matrix analyzed, additional controls may focus on residual pesticides, heavy metals or microbiological contaminants.
For example, a typical analysis performed by an accredited laboratory on a barley-based plant matrix can be carried out by LC-MS, with a limit of quantification between 0.1 and 1 mg/kg. This level of sensitivity allows for the detection of both endogenous ABA naturally present in tissues and any exogenous contributions related to biostimulant treatment.
Manufacturers in the food, biostimulant, nutraceutical, and cosmetics sectors find in these specialized analyses a valuable tool for differentiation and enhanced product safety. Traceability of analyses, the technical expertise of laboratories, and regulatory compliance are all key factors in promoting high-quality products to end customers and regulatory authorities.
YesWeLab, your partner for abscisic acid analysis
To meet the growing analytical needs of industrial companies, YesWeLab offers a comprehensive and innovative solution dedicated to the analysis of abscisic acid and numerous other bioactive compounds of plant origin. Founded in 2020, this French company has established itself as a leading player in the field of laboratory analysis, with a unique approach combining technical expertise and digitalized services.
YesWeLab's strengths for ABA analysis include:
- A network of over 200 partner laboratories across France and Europe, selected for their expertise in the measurement of phytohormones and other molecules of biological interest. This pooling of resources provides access to cutting-edge expertise and state-of-the-art equipment, without the need to deal with multiple contacts.
- An all-in-one digital platform that centralizes all analysis orders, real-time sample tracking, and secure results reception. This approach guarantees complete traceability and seamless management of the analytical process.
- Strict regulatory compliance, with partner laboratories accredited according to ISO 17025and COFRAC, guaranteeing the reliability of results for all regulatory uses.
- A catalog of over 10,000 analyses covering multiple matrices and sectors of activity: agri-food, nutraceuticals, cosmetics, environment, animal health, packaging, and materials. This diversity allows clients to meet all their analytical needs through a single point of contact.
- Fast turnaround times, optimized through intelligent orchestration of analyses between the most relevant partner laboratories, without compromising on quality.
- Personalized support, with a dedicated expert for each client, able to advise on the choice of methods, the interpretation of results and the regulatory implications.
Whether you are a manufacturer of biostimulants, a formulator of natural cosmetic products, a producer of food supplements , or a plant physiology research center, YesWeLab supports you in the precise measurement of abscisic acid and the analytical evaluation of your products. The collaboration process is simple: find the analysis that meets your needs in the online catalog, send your samples using a simplified shipping protocol, and then receive your certified results directly through the platform.
