IAA8 involved in lateral root formation interacts with the TIR1 auxin receptor and ARF transcription factors in Arabidopsis.

The expression of auxin-responsive genes is regulated by the TIR1/AFB auxin receptor-dependent degradation of Aux/IAA transcriptional repressors, which interact with auxin-responsive factors (ARFs). Most of the 29 Aux/IAA genes present in Arabidopsis have not been functionally characterized to date....

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Main Authors: Fumi Arase, Hiroko Nishitani, Mayumi Egusa, Nami Nishimoto, Sumiko Sakurai, Naho Sakamoto, Hironori Kaminaka
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2012-01-01
Series:PLoS ONE
Online Access:http://europepmc.org/articles/PMC3422273?pdf=render
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author Fumi Arase
Hiroko Nishitani
Mayumi Egusa
Nami Nishimoto
Sumiko Sakurai
Naho Sakamoto
Hironori Kaminaka
author_facet Fumi Arase
Hiroko Nishitani
Mayumi Egusa
Nami Nishimoto
Sumiko Sakurai
Naho Sakamoto
Hironori Kaminaka
author_sort Fumi Arase
collection DOAJ
description The expression of auxin-responsive genes is regulated by the TIR1/AFB auxin receptor-dependent degradation of Aux/IAA transcriptional repressors, which interact with auxin-responsive factors (ARFs). Most of the 29 Aux/IAA genes present in Arabidopsis have not been functionally characterized to date. IAA8 appears to have a distinct function from the other Aux/IAA genes, due to its unique transcriptional response to auxin and the stability of its encoded protein. In this study, we characterized the function of Arabidopsis IAA8 in various developmental processes governed by auxin and in the transcriptional regulation of the auxin response. Transgenic plants expressing estrogen-inducible IAA8 (XVE::IAA8) exhibited significantly fewer lateral roots than the wild type, and an IAA8 loss-of-function mutant exhibited significantly more. Ectopic overexpression of IAA8 resulted in abnormal gravitropism. The strong induction of early auxin-responsive marker genes by auxin treatment was delayed by IAA8 overexpression. GFP-fusion analysis revealed that IAA8 localized not only to the nucleus, but, in contrast to other Aux/IAAs, also to the cytosol. Furthermore, we demonstrated that IAA8 interacts with TIR1, in an auxin-dependent fashion, and with ARF proteins, both in yeast and in planta. Taken together, our results show that IAA8 is involved in lateral root formation, and that this process is regulated through the interaction with the TIR1 auxin receptor and ARF transcription factors in the nucleus.
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spelling doaj.art-df2c388ef50e45e5a97309bb1d4cd7452022-12-22T01:56:02ZengPublic Library of Science (PLoS)PLoS ONE1932-62032012-01-0178e4341410.1371/journal.pone.0043414IAA8 involved in lateral root formation interacts with the TIR1 auxin receptor and ARF transcription factors in Arabidopsis.Fumi AraseHiroko NishitaniMayumi EgusaNami NishimotoSumiko SakuraiNaho SakamotoHironori KaminakaThe expression of auxin-responsive genes is regulated by the TIR1/AFB auxin receptor-dependent degradation of Aux/IAA transcriptional repressors, which interact with auxin-responsive factors (ARFs). Most of the 29 Aux/IAA genes present in Arabidopsis have not been functionally characterized to date. IAA8 appears to have a distinct function from the other Aux/IAA genes, due to its unique transcriptional response to auxin and the stability of its encoded protein. In this study, we characterized the function of Arabidopsis IAA8 in various developmental processes governed by auxin and in the transcriptional regulation of the auxin response. Transgenic plants expressing estrogen-inducible IAA8 (XVE::IAA8) exhibited significantly fewer lateral roots than the wild type, and an IAA8 loss-of-function mutant exhibited significantly more. Ectopic overexpression of IAA8 resulted in abnormal gravitropism. The strong induction of early auxin-responsive marker genes by auxin treatment was delayed by IAA8 overexpression. GFP-fusion analysis revealed that IAA8 localized not only to the nucleus, but, in contrast to other Aux/IAAs, also to the cytosol. Furthermore, we demonstrated that IAA8 interacts with TIR1, in an auxin-dependent fashion, and with ARF proteins, both in yeast and in planta. Taken together, our results show that IAA8 is involved in lateral root formation, and that this process is regulated through the interaction with the TIR1 auxin receptor and ARF transcription factors in the nucleus.http://europepmc.org/articles/PMC3422273?pdf=render
spellingShingle Fumi Arase
Hiroko Nishitani
Mayumi Egusa
Nami Nishimoto
Sumiko Sakurai
Naho Sakamoto
Hironori Kaminaka
IAA8 involved in lateral root formation interacts with the TIR1 auxin receptor and ARF transcription factors in Arabidopsis.
PLoS ONE
title IAA8 involved in lateral root formation interacts with the TIR1 auxin receptor and ARF transcription factors in Arabidopsis.
title_full IAA8 involved in lateral root formation interacts with the TIR1 auxin receptor and ARF transcription factors in Arabidopsis.
title_fullStr IAA8 involved in lateral root formation interacts with the TIR1 auxin receptor and ARF transcription factors in Arabidopsis.
title_full_unstemmed IAA8 involved in lateral root formation interacts with the TIR1 auxin receptor and ARF transcription factors in Arabidopsis.
title_short IAA8 involved in lateral root formation interacts with the TIR1 auxin receptor and ARF transcription factors in Arabidopsis.
title_sort iaa8 involved in lateral root formation interacts with the tir1 auxin receptor and arf transcription factors in arabidopsis
url http://europepmc.org/articles/PMC3422273?pdf=render
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