Phytohormone profiling:obtaining highest sensitivity and throughput

Phytohormones regulate a plant’s cellular processes including normal growth and development and their defensive responses to biotic and abiotic stresses.
While phytoprofiling can be extremely complex, the classes of phytohormones can be considered to include auxins (e.g indole-3-acetic acid), cytokinins (e.g zeatin), gibberellins (e.g Gibberellin A1), abscisic acid and ethylene. Each class of compound can act in an inhibitory fashion or engender multiple positive effects. In agricultural monitoring and research, the detection and measurement of all members of the family is important.
We required a rapid, broad spectrum method to analyse the large sample sets that were generated during a series of plant-pathogen interaction studies. In the studies, 11 phytohormones were chosen for targeted analysis. To achieve biologically relevant levels of quantification with reasonable sample sizes and sample preparation techniques that were compatible with the scale of the study, required the use of methods using either selective ion monitoring (SIM) or multiple reaction monitoring (MRM).
A simultaneous full scan/MRM method was also evaluated for untargeted analysis. We found that this approach offerd advantages in information content without significant compromise of the method. An extraction and derivatisation protocol was developed that could be used to efficiently target small organic acids and amino acids from wet plant material.