PIF4 Promotes Expression of LNG1 and LNG2 to Induce Thermomorphogenic Growth in Arabidopsis

Arabidopsis plants adapt to high ambient temperature by a suite of morphological changes including elongation of hypocotyls and petioles and leaf hyponastic growth. These morphological changes are collectively called thermomorphogenesis and are believed to increase leaf cooling capacity by enhancing...

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Main Authors: Geonhee Hwang, Jia-Ying Zhu, Young K. Lee, Sara Kim, Thom T. Nguyen, Jungmook Kim, Eunkyoo Oh
Format: Article
Language:English
Published: Frontiers Media S.A. 2017-07-01
Series:Frontiers in Plant Science
Subjects:
LNG
Online Access:http://journal.frontiersin.org/article/10.3389/fpls.2017.01320/full
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spelling doaj-1748026c1e08486ea2affe98ebe78cfe2020-11-24T21:54:46ZengFrontiers Media S.A.Frontiers in Plant Science1664-462X2017-07-01810.3389/fpls.2017.01320282656PIF4 Promotes Expression of LNG1 and LNG2 to Induce Thermomorphogenic Growth in ArabidopsisGeonhee Hwang0Jia-Ying Zhu1Young K. Lee2Young K. Lee3Sara Kim4Thom T. Nguyen5Jungmook Kim6Eunkyoo Oh7Department of Bioenergy Science and Technology, Chonnam National UniversityGwangju, South KoreaDepartment of Plant Biology, Carnegie Institution for Science, StanfordCA, United StatesCold Spring Harbor Laboratory, Cold Spring HarborNY, United StatesDivision of Biological Sciences and Institute for Basic Science, Wonkwang UniversityIksan, South KoreaDepartment of Bioenergy Science and Technology, Chonnam National UniversityGwangju, South KoreaDepartment of Bioenergy Science and Technology, Chonnam National UniversityGwangju, South KoreaDepartment of Bioenergy Science and Technology, Chonnam National UniversityGwangju, South KoreaDepartment of Bioenergy Science and Technology, Chonnam National UniversityGwangju, South KoreaArabidopsis plants adapt to high ambient temperature by a suite of morphological changes including elongation of hypocotyls and petioles and leaf hyponastic growth. These morphological changes are collectively called thermomorphogenesis and are believed to increase leaf cooling capacity by enhancing transpiration efficiency, thereby increasing tolerance to heat stress. The bHLH transcription factor PHYTOCHROME INTERACTING FACTOR4 (PIF4) has been identified as a major regulator of thermomorphogenic growth. Here, we show that PIF4 promotes the expression of two homologous genes LONGIFOLIA1 (LNG1) and LONGIFOLIA2 (LNG2) that have been reported to regulate leaf morphology. ChIP-Seq analyses and ChIP assays showed that PIF4 directly binds to the promoters of both LNG1 and LNG2. The expression of LNG1 and LNG2 is induced by high temperature in wild type plants. However, the high temperature activation of LNG1 and LNG2 is compromised in the pif4 mutant, indicating that PIF4 directly regulates LNG1 and LNG2 expression in response to high ambient temperatures. We further show that the activities of LNGs support thermomorphogenic growth. The expression of auxin biosynthetic and responsive genes is decreased in the lng quadruple mutant, implying that LNGs promote thermomorphogenic growth by activating the auxin pathway. Together, our results demonstrate that LNG1 and LNG2 are directly regulated by PIF4 and are new components for the regulation of thermomorphogenesis.http://journal.frontiersin.org/article/10.3389/fpls.2017.01320/fullArabidopsishigh temperature stressthermomorphogenesisPIF4LNGgene expression
collection DOAJ
language English
format Article
sources DOAJ
author Geonhee Hwang
Jia-Ying Zhu
Young K. Lee
Young K. Lee
Sara Kim
Thom T. Nguyen
Jungmook Kim
Eunkyoo Oh
spellingShingle Geonhee Hwang
Jia-Ying Zhu
Young K. Lee
Young K. Lee
Sara Kim
Thom T. Nguyen
Jungmook Kim
Eunkyoo Oh
PIF4 Promotes Expression of LNG1 and LNG2 to Induce Thermomorphogenic Growth in Arabidopsis
Frontiers in Plant Science
Arabidopsis
high temperature stress
thermomorphogenesis
PIF4
LNG
gene expression
author_facet Geonhee Hwang
Jia-Ying Zhu
Young K. Lee
Young K. Lee
Sara Kim
Thom T. Nguyen
Jungmook Kim
Eunkyoo Oh
author_sort Geonhee Hwang
title PIF4 Promotes Expression of LNG1 and LNG2 to Induce Thermomorphogenic Growth in Arabidopsis
title_short PIF4 Promotes Expression of LNG1 and LNG2 to Induce Thermomorphogenic Growth in Arabidopsis
title_full PIF4 Promotes Expression of LNG1 and LNG2 to Induce Thermomorphogenic Growth in Arabidopsis
title_fullStr PIF4 Promotes Expression of LNG1 and LNG2 to Induce Thermomorphogenic Growth in Arabidopsis
title_full_unstemmed PIF4 Promotes Expression of LNG1 and LNG2 to Induce Thermomorphogenic Growth in Arabidopsis
title_sort pif4 promotes expression of lng1 and lng2 to induce thermomorphogenic growth in arabidopsis
publisher Frontiers Media S.A.
series Frontiers in Plant Science
issn 1664-462X
publishDate 2017-07-01
description Arabidopsis plants adapt to high ambient temperature by a suite of morphological changes including elongation of hypocotyls and petioles and leaf hyponastic growth. These morphological changes are collectively called thermomorphogenesis and are believed to increase leaf cooling capacity by enhancing transpiration efficiency, thereby increasing tolerance to heat stress. The bHLH transcription factor PHYTOCHROME INTERACTING FACTOR4 (PIF4) has been identified as a major regulator of thermomorphogenic growth. Here, we show that PIF4 promotes the expression of two homologous genes LONGIFOLIA1 (LNG1) and LONGIFOLIA2 (LNG2) that have been reported to regulate leaf morphology. ChIP-Seq analyses and ChIP assays showed that PIF4 directly binds to the promoters of both LNG1 and LNG2. The expression of LNG1 and LNG2 is induced by high temperature in wild type plants. However, the high temperature activation of LNG1 and LNG2 is compromised in the pif4 mutant, indicating that PIF4 directly regulates LNG1 and LNG2 expression in response to high ambient temperatures. We further show that the activities of LNGs support thermomorphogenic growth. The expression of auxin biosynthetic and responsive genes is decreased in the lng quadruple mutant, implying that LNGs promote thermomorphogenic growth by activating the auxin pathway. Together, our results demonstrate that LNG1 and LNG2 are directly regulated by PIF4 and are new components for the regulation of thermomorphogenesis.
topic Arabidopsis
high temperature stress
thermomorphogenesis
PIF4
LNG
gene expression
url http://journal.frontiersin.org/article/10.3389/fpls.2017.01320/full
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