{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,24]],"date-time":"2026-06-24T21:42:31Z","timestamp":1782337351771,"version":"3.54.5"},"reference-count":46,"publisher":"MDPI AG","issue":"13","license":[{"start":{"date-parts":[[2022,6,29]],"date-time":"2022-06-29T00:00:00Z","timestamp":1656460800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"the Applied Basic Research Project of Yunnan Province","award":["202001AT070131"],"award-info":[{"award-number":["202001AT070131"]}]},{"name":"the Applied Basic Research Project of Yunnan Province","award":["202003AD150007"],"award-info":[{"award-number":["202003AD150007"]}]},{"name":"the Western Young Scholars","award":["202001AT070131"],"award-info":[{"award-number":["202001AT070131"]}]},{"name":"the Western Young Scholars","award":["202003AD150007"],"award-info":[{"award-number":["202003AD150007"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["IJMS"],"abstract":"<jats:p>Copper (Cu) is one of the most indispensable micronutrients, and proper Cu homeostasis is required for plants to maintain essential cellular functions. Plants activate the Cu uptake system during Cu limitation. Although SPL7 (SQUAMOSA PROMOTER BINDING PROTEIN-LIKE 7) and CITF1 (Cu-DEFICIENCY INDUCED TRANSCRIPTION FACTOR 1) are two transcription factors in Cu homeostasis, it remains unclear how SPL7 and CITF1 control the Cu uptake system. Here, we reveal that overexpression of CITF1 causes the enhanced tolerance to Cu deficiency and the elevated expression of Cu uptake genes COPT2, FRO4 and FRO5. Electrophoretic mobility shift assays (EMSA) and transient expression assays indicate that SPL7 directly binds to and activates the promoter of CITF1. The overexpression of CITF1 partially rescues the sensitivity of spl7-1 to Cu deficiency. Transcriptome data suggest that SPL7 and CITF1 coregulate the Cu-homeostasis-signaling network, and CITF1 has its own independent functions. Moreover, both SPL7 and CITF1 can directly bind to and activate the promoters of three Cu uptake genes COPT2, FRO4 and FRO5. This work shows the functions of CITF1 in the Cu-homeostasis-signaling network, providing insights into the complicated molecular mechanism underlying Cu homeostasis.<\/jats:p>","DOI":"10.3390\/ijms23137239","type":"journal-article","created":{"date-parts":[[2022,6,29]],"date-time":"2022-06-29T22:43:28Z","timestamp":1656542608000},"page":"7239","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":10,"title":["CITF1 Functions Downstream of SPL7 to Specifically Regulate Cu Uptake in Arabidopsis"],"prefix":"10.3390","volume":"23","author":[{"given":"Yuerong","family":"Cai","sequence":"first","affiliation":[{"name":"CAS Key Laboratory of Tropical Plant Resources and Sustainable Use, Xishuangbanna Tropical Botanical Garden, The Innovative Academy of Seed Design, Chinese Academy of Sciences, Kunming 650223, China"},{"name":"The College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0622-4043","authenticated-orcid":false,"given":"Gang","family":"Liang","sequence":"additional","affiliation":[{"name":"CAS Key Laboratory of Tropical Plant Resources and Sustainable Use, Xishuangbanna Tropical Botanical Garden, The Innovative Academy of Seed Design, Chinese Academy of Sciences, Kunming 650223, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2022,6,29]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"799","DOI":"10.1111\/j.1469-8137.2009.02846.x","article-title":"Copper homeostasis","volume":"182","author":"Burkhead","year":"2009","journal-title":"New Phytol."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"3164","DOI":"10.1105\/tpc.110.078022","article-title":"The bacterial pathogen Xanthomonas oryzae overcomes rice defenses by regulating host copper redistribution","volume":"22","author":"Yuan","year":"2010","journal-title":"Plant Cell"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"919","DOI":"10.1089\/ars.2012.5084","article-title":"Copper and iron homeostasis in plants: The challenges of oxidative stress","volume":"19","author":"Ravet","year":"2013","journal-title":"Antioxid. Redox Signal."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"409","DOI":"10.1071\/FP08288","article-title":"Copper in plants: Acquisition, transport and interactions","volume":"36","author":"Yruela","year":"2009","journal-title":"Funct. Plant Biol."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"1233","DOI":"10.1105\/tpc.104.030452","article-title":"Two P-type ATPases are required for copper delivery in Arabidopsis thaliana chloroplasts","volume":"17","author":"Niyogi","year":"2005","journal-title":"Plant Cell"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"1234","DOI":"10.1039\/c3mt00025g","article-title":"Comparison of global responses to mild deficiency and excess copper levels in Arabidopsis seedlings","volume":"5","author":"Dorcey","year":"2013","journal-title":"Metallomics"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"259","DOI":"10.1016\/j.pbi.2009.05.006","article-title":"Physiological functions of mineral micronutrients (Cu, Zn, Mn, Fe, Ni, Mo, B, Cl)","volume":"12","author":"Mendel","year":"2009","journal-title":"Curr. Opin. Plant Biol."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"299","DOI":"10.1016\/j.pbi.2009.04.008","article-title":"Placing metal micronutrients in context: Transport and distribution in plants","volume":"12","author":"Puig","year":"2009","journal-title":"Curr. Opin. Plant Biol."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"333","DOI":"10.1038\/nchembio.166","article-title":"Facing the challenges of Cu, Fe and Zn homeostasis in plants","volume":"5","author":"Palmer","year":"2009","journal-title":"Nat. Chem. Biol."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"939","DOI":"10.1007\/s00425-001-0706-0","article-title":"Expression of a vegetative-storage-protein gene from Arabidopsis is regulated by copper, senescence and ozone","volume":"214","author":"Mira","year":"2002","journal-title":"Planta"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"577","DOI":"10.1023\/A:1022345507112","article-title":"Identification of a copper transporter family in Arabidopsis thaliana","volume":"51","author":"Puig","year":"2003","journal-title":"Plant Mol. Biol."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"738","DOI":"10.1105\/tpc.111.090431","article-title":"Transcriptome sequencing identifies SPL7-regulated copper acquisition genes FRO4\/FRO5 and the copper dependence of iron homeostasis in Arabidopsis","volume":"24","author":"Bernal","year":"2012","journal-title":"Plant Cell"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"33252","DOI":"10.1074\/jbc.M112.397810","article-title":"COPT6 is a plasma membrane transporter that functions in copper homeostasis in Arabidopsis and is a novel target of SQUAMOSA promoter-binding protein-like 7","volume":"287","author":"Jung","year":"2012","journal-title":"J. Biol. Chem."},{"key":"ref_14","first-page":"476917","article-title":"Function and Regulation of the Plant COPT Family of High-Affinity Copper Transport Proteins","volume":"2014","author":"Puig","year":"2014","journal-title":"Adv. Bot."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"347","DOI":"10.1105\/tpc.108.060137","article-title":"SQUAMOSA Promoter Binding Protein-Like7 Is a Central Regulator for Copper Homeostasis in Arabidopsis","volume":"21","author":"Yamasaki","year":"2009","journal-title":"Plant Cell"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"16369","DOI":"10.1074\/jbc.M700138200","article-title":"Regulation of copper homeostasis by micro-RNA in Arabidopsis","volume":"282","author":"Yamasaki","year":"2007","journal-title":"J. Biol. Chem."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"15932","DOI":"10.1074\/jbc.M801406200","article-title":"MicroRNA-mediated systemic down-regulation of copper protein expression in response to low copper availability in Arabidopsis","volume":"283","author":"Pilon","year":"2008","journal-title":"J. Biol. Chem."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"828","DOI":"10.1104\/pp.113.228239","article-title":"A conserved KIN17 curved DNA-binding domain protein assembles with SQUAMOSA PROMOTER-BINDING PROTEIN-LIKE7 to adapt Arabidopsis growth and development to limiting copper availability","volume":"164","author":"Xing","year":"2014","journal-title":"Plant Physiol."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"3012","DOI":"10.1105\/tpc.17.00363","article-title":"Arabidopsis Pollen Fertility Requires the Transcription Factors CITF1 and SPL7 That Regulate Copper Delivery to Anthers and Jasmonic Acid Synthesis","volume":"29","author":"Yan","year":"2017","journal-title":"Plant Cell"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"18730","DOI":"10.1073\/pnas.0507693102","article-title":"A regulator of nutritional copper signaling in Chlamydomonas is an SBP domain protein that recognizes the GTAC core of copper response element","volume":"102","author":"Kropat","year":"2005","journal-title":"Proc. Natl. Acad. Sci. USA"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"5903","DOI":"10.1093\/jxb\/ers239","article-title":"Rosette iron deficiency transcript and microRNA profiling reveals links between copper and iron homeostasis in Arabidopsis thaliana","volume":"63","author":"Waters","year":"2012","journal-title":"J. Exp. Bot."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"996","DOI":"10.1126\/science.283.5404.996","article-title":"A copper cofactor for the ethylene receptor ETR1 from Arabidopsis","volume":"283","author":"Esch","year":"1999","journal-title":"Science"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"e00245","DOI":"10.1002\/pld3.245","article-title":"Jasmonate induced alternative splicing responses in Arabidopsis","volume":"4","author":"Feng","year":"2020","journal-title":"Plant Direct"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"835","DOI":"10.1007\/s00299-019-02422-0","article-title":"SQUAMOSA promoter-binding protein-like 7 mediates copper deficiency response in the presence of high nitrogen in Arabidopsis thaliana","volume":"38","author":"Mermod","year":"2019","journal-title":"Plant Cell Rep."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"1590","DOI":"10.1105\/tpc.107.050542","article-title":"The Arabidopsis ATNRT2.7 nitrate transporter controls nitrate content in seeds","volume":"19","author":"Chopin","year":"2007","journal-title":"Plant Cell"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"2029","DOI":"10.1073\/pnas.1319953111","article-title":"CLE-CLAVATA1 peptide-receptor signaling module regulates the expansion of plant root systems in a nitrogen-dependent manner","volume":"111","author":"Araya","year":"2014","journal-title":"Proc. Natl. Acad. Sci. USA"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"4103","DOI":"10.1002\/j.1460-2075.1992.tb05503.x","article-title":"Single amino acid substitutions alter helix-loop-helix protein specificity for bases flanking the core CANNTG motif","volume":"11","author":"Fisher","year":"1992","journal-title":"EMBO J."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"2497","DOI":"10.1105\/tpc.151140","article-title":"Update on the basic helix-loop-helix transcription factor gene family in Arabidopsis thaliana","volume":"15","author":"Bailey","year":"2003","journal-title":"Plant Cell"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"3400","DOI":"10.1105\/tpc.104.024315","article-title":"The essential basic helix-loop-helix protein FIT1 is required for the iron deficiency response","volume":"16","author":"Colangelo","year":"2004","journal-title":"Plant Cell"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"1694","DOI":"10.1093\/jxb\/eraa012","article-title":"FIT, a regulatory hub for iron deficiency and stress signaling in roots, and FIT-dependent and -independent gene signatures","volume":"71","author":"Schwarz","year":"2020","journal-title":"J. Exp. Bot."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"385","DOI":"10.1038\/cr.2008.26","article-title":"FIT interacts with AtbHLH38 and AtbHLH39 in regulating iron uptake gene expression for iron homeostasis in Arabidopsis","volume":"18","author":"Yuan","year":"2008","journal-title":"Cell Res."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"503","DOI":"10.1093\/mp\/sss089","article-title":"Requirement and functional redundancy of Ib subgroup bHLH proteins for iron deficiency responses and uptake in Arabidopsis thaliana","volume":"6","author":"Wang","year":"2013","journal-title":"Mol. Plant"},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"2219","DOI":"10.1105\/tpc.110.074096","article-title":"The bHLH transcription factor POPEYE regulates response to iron deficiency in Arabidopsis roots","volume":"22","author":"Long","year":"2010","journal-title":"Plant Cell"},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"787","DOI":"10.1105\/tpc.114.132704","article-title":"The bHLH transcription factor bHLH104 interacts with IAA-LEUCINE RESISTANT3 and modulates iron homeostasis in Arabidopsis","volume":"27","author":"Zhang","year":"2015","journal-title":"Plant Cell"},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"2478","DOI":"10.1104\/pp.15.01827","article-title":"Two bHLH Transcription Factors, bHLH34 and bHLH104, Regulate Iron Homeostasis in Arabidopsis thaliana","volume":"170","author":"Li","year":"2016","journal-title":"Plant Physiol."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"543","DOI":"10.1104\/pp.17.00794","article-title":"Positive Regulator of Iron Homeostasis1, OsPRI1, Facilitates Iron Homeostasis","volume":"175","author":"Zhang","year":"2017","journal-title":"Plant Physiol."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"261","DOI":"10.1111\/pce.13655","article-title":"Oryza sativa Positive Regulator of Iron Deficiency Response 2 (OsPRI2) and OsPRI3 are involved in the maintenance of Fe homeostasis","volume":"43","author":"Zhang","year":"2020","journal-title":"Plant Cell Environ."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"24933","DOI":"10.1073\/pnas.1916892116","article-title":"The iron deficiency response in Arabidopsis thaliana requires the phosphorylated transcription factor URI","volume":"116","author":"Kim","year":"2019","journal-title":"Proc. Natl. Acad. Sci. USA"},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"508","DOI":"10.1105\/tpc.19.00541","article-title":"The Transcription Factor bHLH121 Interacts with bHLH105 (ILR3) and Its Closest Homologs to Regulate Iron Homeostasis in Arabidopsis","volume":"32","author":"Gao","year":"2020","journal-title":"Plant Cell"},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"634","DOI":"10.1016\/j.molp.2020.01.006","article-title":"bHLH121 Functions as a Direct Link that Facilitates the Activation of FIT by bHLH IVc Transcription Factors for Maintaining Fe Homeostasis in Arabidopsis","volume":"13","author":"Lei","year":"2020","journal-title":"Mol. Plant"},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"668","DOI":"10.1111\/jipb.12933","article-title":"Oryza sativa FER-LIKE FE DEFICIENCY-INDUCED TRANSCRIPTION FACTOR (OsFIT\/OsbHLH156) interacts with OsIRO2 to regulate iron homeostasis","volume":"62","author":"Liang","year":"2020","journal-title":"J. Integr. Plant Biol."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"1679","DOI":"10.1111\/pce.14000","article-title":"FIT and bHLH Ib transcription factors modulate iron and copper crosstalk in Arabidopsis","volume":"44","author":"Cai","year":"2021","journal-title":"Plant Cell Environ."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"180","DOI":"10.1104\/pp.112.212407","article-title":"Arabidopsis copper transport protein COPT2 participates in the cross talk between iron deficiency responses and low-phosphate signaling","volume":"162","author":"Puig","year":"2013","journal-title":"Plant Physiol."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"1824","DOI":"10.1039\/C8MT00287H","article-title":"New aspects of iron-copper crosstalk uncovered by transcriptomic characterization of Col-0 and the copper uptake mutant spl7 in Arabidopsis thaliana","volume":"10","author":"Xiang","year":"2018","journal-title":"Metallomics"},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"843","DOI":"10.1104\/pp.96.3.843","article-title":"Effect of fe-catalyzed photooxidation of EDTA on root growth in plant culture media","volume":"96","author":"Hangarter","year":"1991","journal-title":"Plant Physiol."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"735","DOI":"10.1046\/j.1365-313x.1998.00343.x","article-title":"Floral dip: A simplified method for Agrobacterium-mediated transformation of Arabidopsis thaliana","volume":"16","author":"Clough","year":"1998","journal-title":"Plant J."}],"container-title":["International Journal of Molecular Sciences"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1422-0067\/23\/13\/7239\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T23:40:30Z","timestamp":1760139630000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1422-0067\/23\/13\/7239"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2022,6,29]]},"references-count":46,"journal-issue":{"issue":"13","published-online":{"date-parts":[[2022,7]]}},"alternative-id":["ijms23137239"],"URL":"https:\/\/doi.org\/10.3390\/ijms23137239","relation":{},"ISSN":["1422-0067"],"issn-type":[{"value":"1422-0067","type":"electronic"}],"subject":[],"published":{"date-parts":[[2022,6,29]]}}}