The essential bHLH transcription factor FIT1 regulates iron deficiency responses in Arabidopsis thaliana.

2006 ◽  
Author(s):  
Elizabeth Purdy. Colangelo
Keyword(s):  
Arabidopsis Thaliana ◽  
Transcription Factor ◽  
Iron Deficiency ◽  
Bhlh Transcription Factor

scholarly journals The iron deficiency response in Arabidopsis thaliana requires the phosphorylated transcription factor URI

2019 ◽  
Vol 116 (50) ◽  
pp. 24933-24942 ◽  
Author(s):  
Sun A. Kim ◽  
Ian S. LaCroix ◽  
Scott A. Gerber ◽  
Mary Lou Guerinot
Keyword(s):  
Arabidopsis Thaliana ◽  
Transcription Factor ◽  
Transcription Factors ◽  
Iron Deficiency ◽  
Iron Uptake ◽  
Iron Status ◽  
Bhlh Transcription Factor ◽  
Excess Iron ◽  
Phosphorylated Form

Iron is an essential nutrient for plants, but excess iron is toxic due to its catalytic role in the formation of hydroxyl radicals. Thus, iron uptake is highly regulated and induced only under iron deficiency. The mechanisms of iron uptake in roots are well characterized, but less is known about how plants perceive iron deficiency. We show that a basic helix–loop–helix (bHLH) transcription factor Upstream Regulator of IRT1 (URI) acts as an essential part of the iron deficiency signaling pathway in Arabidopsis thaliana. The uri mutant is defective in inducing Iron-Regulated Transporter1 (IRT1) and Ferric Reduction Oxidase2 (FRO2) and their transcriptional regulators FER-like iron deficiency-induced transcription factor (FIT) and bHLH38/39/100/101 in response to iron deficiency. Chromatin immunoprecipitation followed by sequencing (ChIP-seq) reveals direct binding of URI to promoters of many iron-regulated genes, including bHLH38/39/100/101 but not FIT. While URI transcript and protein are expressed regardless of iron status, a phosphorylated form of URI only accumulates under iron deficiency. Phosphorylated URI is subject to proteasome-dependent degradation during iron resupply, and turnover of phosphorylated URI is dependent on the E3 ligase BTS. The subgroup IVc bHLH transcription factors, which have previously been shown to regulate bHLH38/39/100/101, coimmunoprecipitate with URI mainly under Fe-deficient conditions, suggesting that it is the phosphorylated form of URI that is capable of forming heterodimers in vivo. We propose that the phosphorylated form of URI accumulates under Fe deficiency, forms heterodimers with subgroup IVc proteins, and induces transcription of bHLH38/39/100/101. These transcription factors in turn heterodimerize with FIT and drive the transcription of IRT1 and FRO2 to increase Fe uptake.

scholarly journals bHLH transcription factor bHLH115 regulates iron homeostasis in Arabidopsis thaliana

2017 ◽  
Vol 68 (7) ◽  
pp. 1743-1755 ◽  
Author(s):  
Gang Liang ◽  
Huimin Zhang ◽  
Xiaoli Li ◽  
Qin Ai ◽  
Diqiu Yu
Keyword(s):  
Arabidopsis Thaliana ◽  
Transcription Factor ◽  
Iron Homeostasis ◽  
Bhlh Transcription Factor

scholarly journals The bHLH Transcription Factor POPEYE Regulates Response to Iron Deficiency in Arabidopsis Roots

2010 ◽  
Vol 22 (7) ◽  
pp. 2219-2236 ◽  
Author(s):  
Terri A. Long ◽  
Hironaka Tsukagoshi ◽  
Wolfgang Busch ◽  
Brett Lahner ◽  
David E. Salt ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Iron Deficiency ◽  
Bhlh Transcription Factor

scholarly journals Putative cis-regulatory elements predict iron deficiency responses in Arabidopsis roots

2019 ◽  
Author(s):  
Birte Schwarz ◽  
Christina B. Azodi ◽  
Shin-Han Shiu ◽  
Petra Bauer
Keyword(s):  
Transcription Factor ◽  
Iron Deficiency ◽  
Large Scale ◽  
Computational Models ◽  
Regulatory Elements ◽  
Transport Systems ◽  
Fe Deficiency ◽  
Grass Species ◽  
Bhlh Transcription Factor ◽  
Fe Uptake

AbstractIron (Fe) is a key cofactor in many cellular redox processes, including respiration and photosynthesis. Plant Fe deficiency (-Fe) activates a complex regulatory network which coordinates root Fe uptake and distribution to sink tissues, while avoiding over-accumulation of Fe and other metals to toxic levels. In Arabidopsis (Arabidopsis thaliana), FIT (FER-LIKE FE DEFICIENCY-INDUCED TRANSCRIPTION FACTOR), a bHLH transcription factor (TF), is required for up-regulation of root Fe acquisition genes. However, other root and shoot -Fe-induced genes involved in Fe allocation and signaling are FIT-independent. The cis-regulatory code, i.e. the cis-regulatory elements (CREs) and their combinations that regulate plant -Fe-responses, remains largely elusive. Using Arabidopsis genome and transcriptome data, we identified over 100 putative CREs (pCREs) that were predictive of -Fe-induced up-regulation of genes in root tissue. We used large-scale in vitro TF binding data, association with FIT-dependent or FIT-independent co-expression clusters, positional bias, and evolutionary conservation to assess pCRE properties and possible functions. In addition to bHLH and MYB TFs, also B3, NAC, bZIP, and TCP TFs might be important regulators for -Fe responses. Our approach uncovered IDE1 (Iron Deficiency-responsive Element 1), a -Fe response CRE in grass species, to be conserved in regulating genes for biosynthesis of Fe-chelating compounds also in Arabidopsis. Our findings provide a comprehensive source of cis-regulatory information for -Fe-responsive genes, that advances our mechanistic understanding and informs future efforts in engineering plants with more efficient Fe uptake or transport systems.One sentence summary>100 putative cis-regulatory elements robustly predict Arabidopsis root Fe deficiency-responses in computational models, and shed light on the mechanisms of transcriptional regulation.

scholarly journals The bHLH Transcription Factor SPATULA Controls Final Leaf Size in Arabidopsis thaliana

2009 ◽  
Vol 51 (2) ◽  
pp. 252-261 ◽  
Author(s):  
Yasunori Ichihashi ◽  
Gorou Horiguchi ◽  
Stefan Gleissberg ◽  
Hirokazu Tsukaya
Keyword(s):  
Arabidopsis Thaliana ◽  
Transcription Factor ◽  
Leaf Size ◽  
Bhlh Transcription Factor

scholarly journals Systematic analysis of the basic/helix-loop-helix (bHLH) transcription factor family in pummelo (Citrus grandis) and identification of the key members involved in the response to iron deficiency

2020 ◽  
Author(s):  
Xiao-Yong Zhang ◽  
Jie-Ya Qiu ◽  
Qiu-Ling Hui ◽  
Yuan-Yuan Xu ◽  
Yi-Zhong He ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Iron Deficiency ◽  
Fe Deficiency ◽  
Bhlh Transcription Factor ◽  
Sequencing Data ◽  
Systematic Analysis ◽  
Go Annotation ◽  
Basic Helix Loop Helix ◽  
Helix Loop Helix ◽  
Bhlh Proteins

Abstract Background Iron (Fe) deficiency is a common problem in citrus production. As the second largest superfamily of transcription factors (TFs), the basic/helix-loop-helix (bHLH) proteins have been shown to participate in the regulation of Fe homeostasis and a series of other biological and developmental processes in plants. However, this family of members in citrus and their functions in citrus Fe deficiency are still largely unknown. Results In this study, we identified a total of 128 CgbHLHs from pummelo ( Citrus grandis ) genome that were classified into 18 subfamilies by phylogenetic comparison with Arabidopsis thaliana bHLH proteins. All of these CgbHLHs were randomly distributed on nine known (125 genes) and one unknown (3 genes) chromosomes, and 12 and 47 of them were identified to be tandem and segmental duplicated genes, respectively. Sequence analysis showed detailed characteristics of their intron-exon structures, bHLH domain and conserved motifs. Gene ontology (GO) analysis suggested that most of CgbHLHs were annotated to the nucleus, DNA-binding transcription factor activity, response to abiotic stimulus, reproduction, post-embryonic development, flower development and photosynthesis. In addition, 27 CgbHLH proteins were predicted to have direct or indirect protein-protein interactions. Based on GO annotation, RNA sequencing data in public database and qRT-PCR results, several of CgbHLHs were identified as the key candidates that respond to iron deficiency. Conclusions In total, 128 CgbHLH proteins were identified from pummelo, and their detailed sequence and structure characteristics and putative functions were analyzed. This study provides comprehensive information for further functional elucidation of CgbHLH genes in citrus.

scholarly journals AtSK11 and AtSK12 Mediate the Mild Osmotic Stress-Induced Root Growth Response in Arabidopsis

2020 ◽  
Vol 21 (11) ◽  
pp. 3991 ◽  
Author(s):  
Long Dong ◽  
Zhixin Wang ◽  
Jing Liu ◽  
Xuelu Wang
Keyword(s):  
Arabidopsis Thaliana ◽  
Transcription Factor ◽  
Plant Growth ◽  
Osmotic Stress ◽  
Root Growth ◽  
Growth Response ◽  
Glycogen Synthase ◽  
Plant Root ◽  
Bhlh Transcription Factor ◽  
Mild Stress

Although most osmotic stresses are harmful to plant growth and development, certain drought- or polyethylene glycol (PEG)-induced mild osmotic stresses promote plant root growth. The underlying regulatory mechanisms of this response remain elusive. Here, we report that the GLYCOGEN SYNTHASE KINASE 3 (GSK3) genes ARABIDOPSIS THALIANA SHAGGY-RELATED KINASE 11 (AtSK11) (AT5G26751) and AtSK12 (AT3G05840) are involved in the mild osmotic stress (−0.4 MPa) response in Arabidopsis thaliana. When grown on plant medium infused with different concentrations of PEG to mimic osmotic stress, both wild-type (WT) and atsk11atsk12 plants showed stimulated root growth under mild osmotic stress (−0.4 MPa) but repressed root growth under relatively strong osmotic stress (−0.5, −0.6, −0.7 MPa) as compared to the mock condition (−0.25 MPa). The root growth stimulation of atsk11atsk12 was more sensitive to −0.4 MPa treatment than was that of WT, indicating that AtSK11 and AtSK12 inhibit the mild stress-induced root growth response. RNA-seq analysis of WT and atsk11atsk12 plants under three water potentials (−0.25 MPa, −0.4 MPa, −0.6 MPa) revealed 10 differentially expressed candidate genes mainly involved in cell wall homeostasis, which were regulated by AtSK11 and AtSK12 to regulate root growth in response to the mild stress condition (−0.4 MPa). Promoter motif and transcription factor binding analyses suggested that the basic helix-loop-helix (bHLH) transcription factor bHLH69/LJRHL1-LIKE 2 (LRL2) may directly regulate the expression of most −0.4 MPa-responsive genes. These findings indicate that mild osmotic stress (−0.4 MPa) promotes plant growth and that the GSK3 family kinase genes AtSK11 and AtSK12 play a negative role in the induction of root growth in response to mild osmotic stress.

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