Analysis of indole-3-acetic acid (IAA) production in Klebsiella by LC-MS/MS and the Salkowski method

Abstract

Many rhizobacteria isolated from plant rhizosphere produce various phytohormones in the form of secondary metabolites, the most common of which is Indole-3-acetic acid (IAA). Here, we detail analytical protocols of IAA detection and quantification, <i>in vitro</i> and <i>in situ</i>, as recently applied to <i>Klebsiella</i> SGM 81, a rhizobacterium isolated from the rhizosphere of <i>Dianthus caryophyllus</i> (a commercially important flower across the globe). Specifically, we describe a detailed protocol for a colorimetric assay using the Salkowski reagent method, which can be used to screen for the presence of Indole compounds. To further detect and quantify IAA, a highly accurate analytical approach of LC-MS/MS is used. To detect the presence of IAA around the root system of <i>Dianthus caryophyllus, in situ</i> staining of plant roots is done using Salkowski reagent.