PIL5, a phytochrome-interacting bHLH protein, regulates gibberellin responsiveness by binding directly to the GAI and RGA promoters in Arabidopsis seeds

Eunkyoo Oh, Shinjiro Yamaguchi, Jianhong Hu, Jikumaru Yusuke, Byunghyuck Jung, Inyup Paik, Hee Seung Lee, Tai Ping Sun, Yuji Kamiya, Giltsu Choi

Research output: Contribution to journalArticle

252 Citations (Scopus)

Abstract

Previous work showed that PHYTOCHROME-INTERACTING FACTOR3-LIKE5 (PIL5), a light-labile basic helix-loop-helix protein, inhibits seed germination by repressing GIBBERELLIN 3β-HYDROXYLASE1 (GA3ox1) and GA3ox2 and activating a gibberellic acid (GA) catabolic gene (GA2ox2). However, we show persistent light-dependent and PIL5-inhibited germination behavior in the absence of both de novo GA biosynthesis and deactivation by GA2ox2, suggesting that PIL5 regulates not only GA metabolism but also GA responsiveness. PIL5 increases the expression of two GA repressor (DELLA) genes, GA-INSENSITIVE (GAI) and REPRESSOR OF GA1-3 (RGA/RGA1), in darkness. The hypersensitivity of gai-t6 rga-28 to red light and the suppression of germination defects of a rga-28 PIL5 overexpression line show the significant role of this transcriptional regulation in seed germination. PIL5 also increases abscisic acid (ABA) levels by activating ABA biosynthetic genes and repressing an ABA catabolic gene. PIL5 binds directly to GAI and RGA promoters but not to GA and ABA metabolic gene promoters. Together, our results show that light signals perceived by phytochromes cause a reduction in the PIL5 protein level, which in turn regulates the transcription of two DELLA genes directly and that of GA and ABA metabolic genes indirectly.

Original languageEnglish
Pages (from-to)1192-1208
Number of pages17
JournalPlant Cell
Volume19
Issue number4
DOIs
Publication statusPublished - 2007 Apr 1
Externally publishedYes

Fingerprint

Phytochrome
Basic Helix-Loop-Helix Transcription Factors
Gibberellins
phytochrome
Arabidopsis
gibberellins
gibberellic acid
Seeds
promoter regions
Abscisic Acid
seeds
abscisic acid
Germination
proteins
Genes
genes
Light
seed germination
germination
Darkness

ASJC Scopus subject areas

  • Plant Science
  • Cell Biology

Cite this

PIL5, a phytochrome-interacting bHLH protein, regulates gibberellin responsiveness by binding directly to the GAI and RGA promoters in Arabidopsis seeds. / Oh, Eunkyoo; Yamaguchi, Shinjiro; Hu, Jianhong; Yusuke, Jikumaru; Jung, Byunghyuck; Paik, Inyup; Lee, Hee Seung; Sun, Tai Ping; Kamiya, Yuji; Choi, Giltsu.

In: Plant Cell, Vol. 19, No. 4, 01.04.2007, p. 1192-1208.

Research output: Contribution to journalArticle

Oh, Eunkyoo ; Yamaguchi, Shinjiro ; Hu, Jianhong ; Yusuke, Jikumaru ; Jung, Byunghyuck ; Paik, Inyup ; Lee, Hee Seung ; Sun, Tai Ping ; Kamiya, Yuji ; Choi, Giltsu. / PIL5, a phytochrome-interacting bHLH protein, regulates gibberellin responsiveness by binding directly to the GAI and RGA promoters in Arabidopsis seeds. In: Plant Cell. 2007 ; Vol. 19, No. 4. pp. 1192-1208.
@article{832d3b0856a84928a15b62dcf86cac33,
title = "PIL5, a phytochrome-interacting bHLH protein, regulates gibberellin responsiveness by binding directly to the GAI and RGA promoters in Arabidopsis seeds",
abstract = "Previous work showed that PHYTOCHROME-INTERACTING FACTOR3-LIKE5 (PIL5), a light-labile basic helix-loop-helix protein, inhibits seed germination by repressing GIBBERELLIN 3β-HYDROXYLASE1 (GA3ox1) and GA3ox2 and activating a gibberellic acid (GA) catabolic gene (GA2ox2). However, we show persistent light-dependent and PIL5-inhibited germination behavior in the absence of both de novo GA biosynthesis and deactivation by GA2ox2, suggesting that PIL5 regulates not only GA metabolism but also GA responsiveness. PIL5 increases the expression of two GA repressor (DELLA) genes, GA-INSENSITIVE (GAI) and REPRESSOR OF GA1-3 (RGA/RGA1), in darkness. The hypersensitivity of gai-t6 rga-28 to red light and the suppression of germination defects of a rga-28 PIL5 overexpression line show the significant role of this transcriptional regulation in seed germination. PIL5 also increases abscisic acid (ABA) levels by activating ABA biosynthetic genes and repressing an ABA catabolic gene. PIL5 binds directly to GAI and RGA promoters but not to GA and ABA metabolic gene promoters. Together, our results show that light signals perceived by phytochromes cause a reduction in the PIL5 protein level, which in turn regulates the transcription of two DELLA genes directly and that of GA and ABA metabolic genes indirectly.",
author = "Eunkyoo Oh and Shinjiro Yamaguchi and Jianhong Hu and Jikumaru Yusuke and Byunghyuck Jung and Inyup Paik and Lee, {Hee Seung} and Sun, {Tai Ping} and Yuji Kamiya and Giltsu Choi",
year = "2007",
month = "4",
day = "1",
doi = "10.1105/tpc.107.050153",
language = "English",
volume = "19",
pages = "1192--1208",
journal = "Plant Cell",
issn = "1040-4651",
publisher = "American Society of Plant Biologists",
number = "4",

}

TY - JOUR

T1 - PIL5, a phytochrome-interacting bHLH protein, regulates gibberellin responsiveness by binding directly to the GAI and RGA promoters in Arabidopsis seeds

AU - Oh, Eunkyoo

AU - Yamaguchi, Shinjiro

AU - Hu, Jianhong

AU - Yusuke, Jikumaru

AU - Jung, Byunghyuck

AU - Paik, Inyup

AU - Lee, Hee Seung

AU - Sun, Tai Ping

AU - Kamiya, Yuji

AU - Choi, Giltsu

PY - 2007/4/1

Y1 - 2007/4/1

N2 - Previous work showed that PHYTOCHROME-INTERACTING FACTOR3-LIKE5 (PIL5), a light-labile basic helix-loop-helix protein, inhibits seed germination by repressing GIBBERELLIN 3β-HYDROXYLASE1 (GA3ox1) and GA3ox2 and activating a gibberellic acid (GA) catabolic gene (GA2ox2). However, we show persistent light-dependent and PIL5-inhibited germination behavior in the absence of both de novo GA biosynthesis and deactivation by GA2ox2, suggesting that PIL5 regulates not only GA metabolism but also GA responsiveness. PIL5 increases the expression of two GA repressor (DELLA) genes, GA-INSENSITIVE (GAI) and REPRESSOR OF GA1-3 (RGA/RGA1), in darkness. The hypersensitivity of gai-t6 rga-28 to red light and the suppression of germination defects of a rga-28 PIL5 overexpression line show the significant role of this transcriptional regulation in seed germination. PIL5 also increases abscisic acid (ABA) levels by activating ABA biosynthetic genes and repressing an ABA catabolic gene. PIL5 binds directly to GAI and RGA promoters but not to GA and ABA metabolic gene promoters. Together, our results show that light signals perceived by phytochromes cause a reduction in the PIL5 protein level, which in turn regulates the transcription of two DELLA genes directly and that of GA and ABA metabolic genes indirectly.

AB - Previous work showed that PHYTOCHROME-INTERACTING FACTOR3-LIKE5 (PIL5), a light-labile basic helix-loop-helix protein, inhibits seed germination by repressing GIBBERELLIN 3β-HYDROXYLASE1 (GA3ox1) and GA3ox2 and activating a gibberellic acid (GA) catabolic gene (GA2ox2). However, we show persistent light-dependent and PIL5-inhibited germination behavior in the absence of both de novo GA biosynthesis and deactivation by GA2ox2, suggesting that PIL5 regulates not only GA metabolism but also GA responsiveness. PIL5 increases the expression of two GA repressor (DELLA) genes, GA-INSENSITIVE (GAI) and REPRESSOR OF GA1-3 (RGA/RGA1), in darkness. The hypersensitivity of gai-t6 rga-28 to red light and the suppression of germination defects of a rga-28 PIL5 overexpression line show the significant role of this transcriptional regulation in seed germination. PIL5 also increases abscisic acid (ABA) levels by activating ABA biosynthetic genes and repressing an ABA catabolic gene. PIL5 binds directly to GAI and RGA promoters but not to GA and ABA metabolic gene promoters. Together, our results show that light signals perceived by phytochromes cause a reduction in the PIL5 protein level, which in turn regulates the transcription of two DELLA genes directly and that of GA and ABA metabolic genes indirectly.

UR - http://www.scopus.com/inward/record.url?scp=34250651201&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=34250651201&partnerID=8YFLogxK

U2 - 10.1105/tpc.107.050153

DO - 10.1105/tpc.107.050153

M3 - Article

VL - 19

SP - 1192

EP - 1208

JO - Plant Cell

JF - Plant Cell

SN - 1040-4651

IS - 4

ER -