Ethylene and auxin interaction in the control of adventitious rooting in Arabidopsis thaliana

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...

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Bibliographic Details
Published in:Journal of experimental botany 2016-12, Vol.67 (22), p.6445-6458
Main Authors: Veloccia, A., Fattorini, L., Rovere, F. Della, Sofo, A., D’Angeli, S., Betti, C., Falasca, G., Altamura, M.M.
Format: Article
Language:English
Subjects:
Arabidopsis - growth & development
Arabidopsis - physiology
Ethylenes - metabolism
In Situ Hybridization
Indoleacetic Acids - metabolism
Indoles - metabolism
Plant Growth Regulators - physiology
Plant Roots - growth & development
Plant Roots - physiology
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Summary: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. This research investigated the role of ethylene in AR formation in dark-grown Arabidopsis thaliana seedlings, and its interaction with IAA/IBA. A number of mutants/transgenic lines were exposed to various treatments, and mRNA in situ hybridizations were carried out and hormones were quantified. In the wild-type, the ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC) at 0.1 μM enhanced AR formation when combined with IBA (10 μM), but reduced it when applied alone; this effect did not occur in the ein3eil1 ethyleneinsensitive mutant. ACC inhibited the expression of the IAA-biosynthetic genes WEI2, WEI7, and YUC6, but enhanced IBA-to-IAA conversion, as shown by the response of the ech2ibr10 mutant and an increase in the endogenous levels of IAA. The ethylene effect was independent of auxin-signaling by TIR1-AFB2 and IBA-efflux by ABCG carriers, but it was dependent on IAA-influx by AUX1/LAX3. Taken together, the results demonstrate that a crosstalk involving ethylene signaling, IAA-influx, and IBA-to-IAA conversion exists between ethylene and IAA in the control of AR formation.
ISSN:0022-0957
1460-2431
DOI:10.1093/jxb/erw415