Amide-linked conjugates of indole-3-acetic acid (IAA) are putative storage or inactivation forms of the growth hormone auxin. Here, we describe the Arabidopsis iar3 mutant that displays reduced sensitivity to IAA-Ala. IAR3 is a member of a family of Arabidopsis genes related to the previously isolated ILR1 gene, which encodes an IAA-amino acid hydrolase selective for IAA-Leu and IAA-Phe. IAR3 a...

Analysis of neutral and acidic ethyl acetate extracts from culture medium of Azospirillum brasilense 703Ebc by high-performance liquid chromatography (HPLC) and combined gas chromatography-mass spectrometry demonstrated the presence of indole-3-acetic acid (IAA), indole-3-ethanol, indole-3-methanol, and indole-3-lactic acid. IAA in media of 20 strains of A. brasilense and Azospirillum lipoferum...

The Aux/IAA proteins are auxin-sensitive repressors that mediate diverse physiological and developmental processes in plants [1, 2]. There are 29 Aux/IAA genes in Arabidopsis that exhibit unique but partially overlapping patterns of expression [3]. Although some studies have suggested that individual Aux/IAA genes have specialized function, genetic analyses of the family have been limited by th...

Many plant-associated bacteria synthesize the phytohormone indoleacetic acid (IAA). While IAA produced by phytopathogenic bacteria, mainly by the indoleacetamide pathway, has been implicated in the induction of plant tumors, it is not clear whether IAA synthesized by beneficial bacteria, usually via the indolepyruvic acid pathway, is involved in plant growth promotion. To determine whether bact...

IAA in plant tissues has been analyzed by a number of physico-chernical methods. GC-MS has been used for both qualitative and quantitative analyses with deuterium-labeled IAA as the internal standard (Caruso et al. 1978, Magnus et al. 1980, Pengelly et al. 1981). This GC-MS method however, requires extensive purification of the plant extract and additional procedures for the preparation of vola...

Technological development led to an increased interest in systems biological approaches in plants to characterize developmental mechanism and candidate genes relevant to specific tissue or cell morphology. AUX-IAA proteins are important plant-specific putative transcription factors. There are several reports on physiological response of this family in Arabidopsis but in cotton fiber the transcr...

Two mutants of Arabidopsis thaliana that are resistant to growth inhibition by indole-3-acetic acid (IAA)-phenylalanine have been isolated. Both mutants were 2- to 3-fold more resistant than wild type to inhibition by IAA-phenylalanine, IAA-alanine, and IAA-glycine in root growth assays. The mutant icr1 (but not icr2) also shows some resistance to IAA-aspartate. Studies using 3H-labeled IAA-phe...

Adventitious roots (ARs) are post-embryonic roots essential for plant survival and propagation. Indole-3-acetic acid (IAA) is the auxin that controls AR formation; however, its precursor indole-3-butyric acid (IBA) is known to enhance it. Ethylene affects many auxin-dependent processes by affecting IAA synthesis, transport and/or signaling, but its role in AR formation has not been elucidated. ...

Chloroplasts, Compartmental Analysis, Indole-3-acetic Acid (LAA), IAA Conjugation, Permeability A compartmental analysis of the distribution of the plant hormone indole-3-acetic acid (IAA) was performed with mesophyll cells of spinach leaves. The results indicated that up to about 45% of the total amount of free IAA in the laminae of spinach is localized within the chloroplasts, although these ...