Comparison of indole derivatives as potential intermediates of auxin biosynthesis in Arabidopsis

Abstract

Biosynthesis of indole-3-acetic acid (IAA) is crucial for the regulation of plant growth and morphological changes. However, the pathways of IAA biosynthesis have not been completely understood. Although indole derivatives have been proposed to be intermediates of the pathway, it has not been thoroughly elucidated whether the proposed intermediates are indeed converted into an active auxin, IAA, or intermediate metabolites other than IAA. In the present work, we examined 11 indole derivatives whether they are indeed IAA intermediates. The indole derivatives were examined by measuring their effects on recovery from auxin-deficiency conditions caused by l-aminooxyphenylpropionic acid (AOPP), which we previously identified as an IAA biosynthesis inhibitor. We estimated auxin activity of each indole derivative by analyzing auxin-inducible marker gene expression and root morphology in Arabidopsis. We found that indole-3-pyruvic acid most effectively recovered seedlings from auxin deficiency among the indole derivatives examined, followed by Nhydroxyl tryptamine and indole-3-acetonitrile, with effective recovery from the auxin deficiency caused by AOPP. We also found that tryptophol recovered the root growth defects. Among the indole derivatives examined, only indole-3-acrylic acid did not show effective recovery from auxin deficiency. These results provide information on which compounds are reliable intermediates of IAA biosynthesis pathways in Arabidopsis.

Aminooxy‐naphthylpropionic acid and its derivatives are inhibitors of auxin biosynthesis targeting l‐tryptophan aminotransferase: structure–activity relationships

“…We previously demonstrated that the expression of auxin‐responsive genes was downregulated as a result of auxin deficiency caused by treatment with an inhibitor of auxin biosynthesis (Soeno et al ., ; Ishida et al ., ). Thus, to investigate the effects of inhibitors on auxin signaling, we analyzed expression levels of the auxin‐responsive Aux / IAA1 and Aux / IAA5 genes in response to treatment with KOK1169, AOPP and PEO‐IAA.…”

Diversity, Lifestyle, Genomics, and Their Functional Role of Cochliobolus, Bipolaris, and Curvularia Species in Environmental Remediation and Plant Growth Promotion under Biotic and Abiotic Stressors

“…One of the most important phytohormones, indole acetic acid (IAA), controls cell growth and division [ 106 ]. The plant-derived IAA is also produced by soil and endophytic microorganisms and has been shown to enhance plant development [ 107 , 108 ]. Endophytic fungi, such as Curvularia species, have recently been found to produce IAA in the tissues of aerial plant parts [ 109 ].…”

Antagonistic Effect and Plant Growth Hormone Produced by Endophyte Bacillus amyloliquefaciens LKM-UL Isolated from Cocoa Plant

“…Other study showed Bacillus subtilis LK14 isolated from Moringa peregrine plant produced auxin hormones that can improved the growth of Solanum lycopersicum [21]. Auxin hormones were known to play important role in cell elongation, division and enlargement [22] and GA could stimulated the shoot length, chlorophyll contents and increased biomass of rice plant [23]. Interestingly, B. amyloliquefaciens LKM-UL isolated from cocoa plant have the ability to produce multiple types of auxins (1-naphthalene acetic acid, tryptamine, 3-indole propionic acid and indole-3-butyric acid), gibberellic acid and cytokinins (trans-zeatin and kinetin).…”