Quantitative Auxin Metabolite Profiling Using Stable Isotope Dilution UHPLC-MS/MS.

Auxin, a plant hormone, is able to stimulate growth and to control developmental processes. To get a deeper level of understanding of how auxin activity is regulated in planta, we have developed a sensitive and selective mass spectrometry-based protocol for multiplex quantification of indole 3-acetic acid (IAA) as well as its precursors and degradation products. As part of the protocol development, we have also established a derivatization protocol for the IAA precursors IPyA and IAAld, compounds that are highly labile during sample extraction and purification. This article describes a standard isotope dilution method for quantitative profiling of the IAA metabolome in small amounts of plant tissues. © 2016 by John Wiley & Sons, Inc.