PIF4 Regulates the Expression of SAURs in Plant Thermomorphogenesis

doi:10.7525/j.issn.1673-5102.2025.02.004

Abstract

Abstract:

Thermomorphogenesis is defined as a series of morphological changes that occur in higher plants when the temperature is higher than an optimal temperature and lower than the stress temperature. Among these morphological changes， hypocotyl elongation induced by high temperature has received the most attention and has been studied most deeply. SMALL AUXIN UP RNA（SAUR） gene family plays a key role in promoting growth and cell elongation. However， little is known about the molecular mechanism of high temperature regulation of SAURs. In this study， Arabidopsis Col-0 wild type， pif4-2 mutant and four transgenic plants were used as research materials. Real-time Quantitative PCR（qPCR）， chromatin immunoprecipitation（ChIP）， double luciferase reporter gene detection and phenotypic analysis were used to explore the molecular mechanisms of high temperature regulated SAUR1-SAUR4. The results were as follows： high temperature promoted SAUR1-SAUR4 transcription and this promotion required transcription factor PHYTOCHROME-INTERACTING FACTOR 4（PIF4）； transcription factor PIF4 binded to the E-box region in the promoter regions of SAUR1-SAUR4， and mild-high temperature enhanced these binding； auxin was downstream of PIF4 in the thermomorphogenesis signaling pathway； auxin signaling pathway was required for the regulation of SAUR1-SAUR4 by PIF4. These results indicated that high temperature regulated the transcription of these four genes by influencing the binding strength of PIF4 and SAUR1-SAUR4 promoter chromatin. This research deepens our understanding of the molecular mechanism underlying hypocotyl elongation downstream genes regulated by high temperature during thermomorphogenesis， thus enriching the theoretical basis of heat-resistant breeding.

Key words: thermomorphogenesis, hypocotyl elongation, PIF4, SAURs

CLC Number:

Q945.78

Xiyao WANG, Yanling LIU, Xin WANG. PIF4 Regulates the Expression of SAURs in Plant Thermomorphogenesis[J]. Bulletin of Botanical Research, 2025, 45(2): 181-190.

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引物名称 Primer name	引物序列 Primer sequence（5′→3′）	引物名称 Primer name	引物序列 Primer sequence（5′→3′）
SAUR1-F1	TCTAGAATGGGTATCCAATTG	pSAUR2-F	CTCGAGGGAACCACAAACCTCTTC
SAUR1-R1	GTCGACTCATGAACCACTTAG	pSAUR2-R	GGATCCATCTATCTTTCAAATGAAC
PIF4-F	GAATTCATGCTCCTCCTTGTATC	pSAUR3-F	CTCGAGTGGAACAAAGGATGGT
PIF4-R	CTCGAGCTAGTGGTCCAAACGAG	pSAUR3-R	GGATCCGTCTTCTTATTTATGTTTG
pSAUR1-F	CTCGAGCTCCATTATGTCAATAG	pSAUR4-F	CTCGAGCATTGAGGAACGCATTA
pSAUR1-R	GGATCCCTTTGAGGACTAATGC	pSAUR4-R	GGATCCCTTTAAAAGCAAGAAG

引物名称 Primer name	引物序列 Primer sequence（5′→3′）	引物名称 Primer name	引物序列 Primer sequence（5′→3′）
UBQ1-F	TTCCTTGATGATGCTTGCTC	SAUR2-R	GGCTTTACGCAACAAGGCTT
UBQ1-R	TTGACAGCTCTTGGGTGAAG	SAUR3-F	ACTTCAGGGCTTGTTCCGAA
SAUR1-F	TGATCGGACTCTCTCAGGCA	SAUR3-R	GGTATCGTCAAGCCACCCAT
SAUR1-R	GTACCCGACGTAGCCAAGAG	SAUR4-F	TGTCGCGTGTGATCAACTCT
SAUR2-F	GGAGAAGACGAGATGGAGACG	SAUR4-R	TCTCCGACATAAACCGCAACA

引物名称 Primer name	引物序列 Primer sequence（5′→3′）	引物名称 Primer name	引物序列 Primer sequence（5′→3′）
SAUR1-F1	GGGTCAAGAGGTCACGAGGA	SAUR3-R1	AGCAACAAACCTTCACCCCT
SAUR1-R1	ACTTCATTATGTTCTAGAAAC	SAUR3-F2	GGAGAAGACGAGATGGAGACG
SAUR1-F2	AGCCACCTTTGAGAGAAAGCA	SAUR3-R2	AGAATCTACCAACTGTATTAGTGCG
SAUR1-R2	TGGGAACAAAAGCATCTGCA	SAUR3-F3	GCAAATAGCTATAGATCTATGGGGA
SAUR1-F3	AGCCACCTTTGAGAGAAAGCA	SAUR3-R3	TGTTTGTTAAATTTTCAGCTCCATAGA
SAUR1-R3	TTGTTTGTGGGGTGAGGCAT	SAUR3-F4	TGAGCTAAGCCATGTGAGCC
SAUR1-F4	AGGACAAGGCATAAGCATGTGA	SAUR3-R4	AAACAGTACGATGCGATATTTTGA
SAUR1-R4	TGCAAATGAGTAAGAAGGGAGA	SAUR4-F1	TGGTTGAAAAATCCATCTTACAAAGA
SAUR2-F1	GGAACCACAAACCTCTTCTTCTC	SAUR4-R1	TGATGTAAGTCAGAGCTGGGT
SAUR2-R1	TCCAAACATAAATAAGAAGACATGGGT	SAUR4-F2	AGGATGGTGGATCACATGCA
SAUR2-F2	AGACAACGAGGGGAAGAAGT	SAUR4-R2	TGATAAAATTGTGCAGTACTGTTTCA
SAUR2-R2	AGCTAAGCCATGTGAGCCAG	SAUR4-F3	ATAAATAATGGAAATGAAACACGTGAC
SAUR2-F3	TCAGCTCCATAGATAGTTTTGATCA	SAUR4-R3	TTAATCAGTTGAGTTAATATCACTGCT
SAUR2-R3	AGCCACAGTCACAATCATCCT	SAUR4-F4	GCCACCATTTTCAAGAGCCA
SAUR2-F4	AAAATCATGCACTAATTAAGACTTCAC	SAUR4-R4	AGTTTGCAGAGTTTCACATGGT
SAUR2-R4	AGAATCTACCAACTGTATTAGTGCG	ACT2-F	CTGTCATGTAACACGCGGAT
SAUR3-F1	TGTGTCTTAAACGCGATATCTTTT	ACT2-R	ATAACGTGACCTGGCTGTCA