Cross-reactivities of anti-nicotianamine antibody with mugineic acid and related compounds

Abstract

Nicotianamine (NA) is a stable precursor of mugineic acid-family phytosiderophores (MAs), which are iron-chelators secreted from roots of some gramineous plants under iron-deficiency stress (Takagi 1976; Kawai et al. 1988a). Recently a cell-free system for the synthesis of NA was developed by Shojima et al. (1989a, b). In that system, the incorporation of radioactivity from the substrate L-[1-¹⁴C]methionine into NA was measured after separation by HPLC (conventional amino acid analyzer). However, this assay system is time-consuming and not suitable for a large number of samples as it takes 3 h to analyze one sample. We, thus, raised polyclonal antibodies against NA to develop a rapid assay system with high sensitivity. In this study, we report on the development of a radioimmunoassay of NA with anti-NA antibodies and cross-reactivities with MAs and related compounds.