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 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 ethylene-insensitive 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.
Dipartimento di Biologia Ambientale, Sapienza Università di Roma, Roma, Italy.
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0000-0002-7312-9871
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Veloccia
Dipartimento di Biologia Ambientale, Sapienza Università di Roma, Roma, Italy.
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0000-0002-8732-7131
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Fattorini
Dipartimento di Biologia Ambientale, Sapienza Università di Roma, Roma, Italy.
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0000-0002-9454-8522
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Della Rovere
School of Agricultural, Forestry, Food and Environmental Sciences (SAFE), Università degli Studi della Basilicata, Potenza, Italy.
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0000-0003-0305-308X
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Sofo
Dipartimento di Biologia Ambientale, Sapienza Università di Roma, Roma, Italy.
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0000-0002-3971-7872
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D'Angeli
Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Gent, Belgium.|Department of Plant Systems Biology, VIB, 9052 Gent, Belgium.
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0000-0003-3522-6440
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Betti
Dipartimento di Biologia Ambientale, Sapienza Università di Roma, Roma, Italy.
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0000-0002-2323-530X
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Falasca
Dipartimento di Biologia Ambientale, Sapienza Università di Roma, Roma, Italy mariamaddalena.altamura@uniroma1.it.
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0000-0001-9848-6579
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Altamura
D017360:Arabidopsis / Q000254:growth & development* / Q000502:physiology; D005030:Ethylenes / Q000378:metabolism*; D017403:In Situ Hybridization; D007210:Indoleacetic Acids / Q000378:metabolism*; D007211:Indoles / Q000378:metabolism; D010937:Plant Growth Regulators / Q000502:physiology*; D018517:Plant Roots / Q000254:growth & development* / Q000502:physiology
D005030:Ethylenes; D007210:Indoleacetic Acids; D007211:Indoles; D010937:Plant Growth Regulators; C014612:indolebutyric acid; C030737:indoleacetic acid; C036216:ethylene

Arabidopsis thaliana
; Adventitious roots; IAA-biosynthesis and transport; IBA transport.; IBA-to-IAA conversion; auxin; ethylene signaling