Transcription of DWARF4 plays a crucial role in auxin-regulated root elongation in addition to brassinosteroid homeostasis in Arabidopsis thaliana

Yuya Yoshimitsu; Kiwamu Tanaka; Wataru Fukuda; Tadao Asami; Shigeo Yoshida; Ken-Ichiro Hayashi; Yuji Kamiya; Yusuke Jikumaru; Tomoaki Shigeta; Yasushi Nakamura; Tomoaki Matsuo; Shigehisa Okamoto

doi:10.1371/journal.pone.0023851

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Transcription of DWARF4 plays a crucial role in auxin-regulated root elongation in addition to brassinosteroid homeostasis in Arabidopsis thaliana

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Transcription of DWARF4 plays a crucial role in auxin-regulated root elongation in addition to brassinosteroid homeostasis in Arabidopsis thaliana

Yuya Yoshimitsu, Kiwamu Tanaka, Wataru Fukuda, Tadao Asami, Shigeo Yoshida, Ken-Ichiro Hayashi, Yuji Kamiya, Yusuke Jikumaru, Tomoaki Shigeta, Yasushi Nakamura, …

PloS one, Vol.6(8), pp.e23851-e23851

2011

DOI: https://doi.org/10.1371/journal.pone.0023851

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https://hdl.handle.net/2376/108892

PMCID: PMC3166115

PMID: 21909364

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Abstract

Transcription, Genetic - drug effects

Arabidopsis - growth & development

Triiodobenzoic Acids - pharmacology

Cytochrome P-450 Enzyme System - metabolism

Plant Roots - genetics

RNA, Messenger - metabolism

Recombinant Fusion Proteins - metabolism

Seedlings - growth & development

Plant Roots - drug effects

Arabidopsis Proteins - metabolism

Brassinosteroids - metabolism

Plants, Genetically Modified

Biological Transport - drug effects

Homeostasis - drug effects

Plant Roots - growth & development

Arabidopsis Proteins - genetics

Arabidopsis - drug effects

RNA, Messenger - genetics

Seedlings - drug effects

Arabidopsis - genetics

Gene Expression Regulation, Plant - drug effects

Indoleacetic Acids - pharmacology

Cytochrome P-450 Enzyme System - genetics

Homeostasis - genetics

Seedlings - metabolism

The expression of DWARF4 (DWF4), which encodes a C-22 hydroxylase, is crucial for brassinosteroid (BR) biosynthesis and for the feedback control of endogenous BR levels. To advance our knowledge of BRs, we examined the effects of different plant hormones on DWF4 transcription in Arabidopsis thaliana. Semi-quantitative reverse-transcriptase PCR showed that the amount of the DWF4 mRNA precursor either decreased or increased, similarly with its mature form, in response to an exogenously applied bioactive BR, brassinolide (BL), and a BR biosynthesis inhibitor, brassinazole (Brz), respectively. The response to these chemicals in the levels of β-glucuronidase (GUS) mRNA and its enzymatic activity is similar to the response of native DWF4 mRNA in DWF4::GUS plants. Contrary to the effects of BL, exogenous auxin induced GUS activity, but this enhancement was suppressed by anti-auxins, such as α-(phenylethyl-2-one)-IAA and α-tert-butoxycarbonylaminohexyl-IAA, suggesting the involvement of SCF(TIR1)-mediated auxin signaling in auxin-induced DWF4 transcription. Auxin-enhanced GUS activity was observed exclusively in roots; it was the most prominent in the elongation zones of both primary and lateral roots. Furthermore, auxin-induced lateral root elongation was suppressed by both Brz application and the dwf4 mutation, and this suppression was rescued by BL, suggesting that BRs act positively on root elongation under the control of auxin. Altogether, our results indicate that DWF4 transcription plays a novel role in the BR-auxin crosstalk associated with root elongation, in addition to its role in BR homeostasis.

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Title: Transcription of DWARF4 plays a crucial role in auxin-regulated root elongation in addition to brassinosteroid homeostasis in Arabidopsis thaliana
Creators: Yuya Yoshimitsu - Department of Agricultural Sciences and Natural Resources, Kagoshima University, Kagoshima, Japan
Kiwamu Tanaka
Wataru Fukuda
Tadao Asami
Shigeo Yoshida
Ken-Ichiro Hayashi
Yuji Kamiya
Yusuke Jikumaru
Tomoaki Shigeta
Yasushi Nakamura
Tomoaki Matsuo
Shigehisa Okamoto
Publication Details: PloS one, Vol.6(8), pp.e23851-e23851
Academic Unit: Plant Pathology, Department of
Publisher: United States
Identifiers: 99900547034301842
Language: English
Resource Type: Journal article