A Mass Spectrometry Approach Reveals Fatty Acid Isomerism in Tomato Cold Tolerance

Area of Science:

• Plant Physiology
• Metabolomics
• Molecular Biology

Background:

• Plants adapt to environmental changes by dynamically modulating fatty acids (FAs).
• Understanding the role of specific FAs and their isomers in plant stress tolerance is crucial.
• Tomato (Solanum lycopersicum) serves as a model for studying cold stress responses.

Purpose of the Study:

• To explore the landscape of fatty acid isomers involved in tomato cold tolerance.
• To elucidate the regulatory mechanisms of fatty acid desaturation under cold stress.
• To demonstrate the practical application of fatty acid isomers in enhancing plant stress resilience.

Main Methods:

• Utilized an enhanced mass spectrometry approach combining N-(4-aminomethylphenyl) pyridium derivatization.
• Employed charge-tagging Paternò-Büchi (PB) photochemical reaction for double bond position identification.
• Integrated reversed-phase liquid chromatography with tandem mass spectrometry for FA detection and isomer analysis.

Main Results:

• Identified several saturated and unsaturated fatty acid isomers contributing to cold tolerance in tomato mutants (slhy5 and slfad).
• Demonstrated that SlHY5 regulates SlFAD2 gene expression under cold stress, impacting fatty acid desaturation.
• Showed partial rescue of cold sensitivity in slfad mutants upon application of specific FA isomers.

Conclusions:

• Isomeric variations in fatty acids are critical for plant physiological responses to cold stress.
• SlHY5 plays a key role in mediating cold-induced fatty acid desaturation via SlFAD2.
• The developed methodology provides a valuable tool for studying plant metabolic networks and stress adaptation.