Label-Free Rapid Quantification of Abscisic Acid in Xylem Sap Samples Using Surface Plasmon Resonance

Area of Science:

• Plant Physiology
• Biotechnology
• Analytical Chemistry

Background:

• Abscisic acid (ABA) is a critical phytohormone regulating plant adaptation to abiotic stresses like drought and salinity.
• Accurate and rapid ABA detection is essential for understanding plant stress responses and improving crop resilience.
• Existing methods for ABA quantification can be time-consuming and complex.

Purpose of the Study:

• To develop a novel, label-free, non-competitive immunoassay for rapid and direct detection of ABA.
• To utilize a surface plasmon resonance (SPR) biosensor for quantifying ABA in plant samples.
• To validate the performance of the SPR biosensor against a standard method for ABA measurement.

Main Methods:

• Functionalization of an SPR sensor chip with an anti-ABA antibody.
• Characterization of antibody affinity, binding kinetics, and specificity using SPR.
• Direct quantification of ABA in tomato xylem sap under drought and salinity stress.
• Comparison of SPR biosensor results with ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS).

Main Results:

• The SPR biosensor demonstrated high specificity and sensitivity for ABA detection, with a limit of detection of 1.36 ng/mL.
• The assay provided rapid and direct quantification of ABA in tomato xylem sap.
• ABA levels measured by the SPR biosensor accurately reflected stress conditions and correlated well with UPLC-MS/MS results.

Conclusions:

• A novel SPR-based immunosensor offers a rapid, sensitive, and reliable method for direct ABA quantification.
• This technology facilitates real-time monitoring of ABA levels in plants experiencing abiotic stress.
• The developed biosensor is a valuable tool for plant stress physiology research and crop improvement strategies.