{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,12]],"date-time":"2026-10-12T19:10:33Z","timestamp":1791832233407,"version":"4.3.4"},"reference-count":48,"publisher":"MDPI AG","issue":"23","license":[{"start":{"date-parts":[[2024,12,6]],"date-time":"2024-12-06T00:00:00Z","timestamp":1733443200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["32272753"],"award-info":[{"award-number":["32272753"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Plants"],"abstract":"<jats:p>Iron (Fe) is an essential micronutrient for plants. Due to the low Fe bioavailability in cultivated soils, Fe deficiency is a widespread agricultural problem. In this study, we present the functional characterization of a petunia (Petunia hybrida) basic-helix-loop-helix transcription factor PhbHLH121 in response to Fe shortage. Real-time PCR revealed that the expression of PhbHLH121 in petunia roots and shoots was downregulated under Fe-limited conditions. CRISPR\/Cas9-edited phbhlh121 mutant plants were generated to investigate the functions of PhbHLH121 in petunia. Loss-of-function of PhbHLH121 enhanced petunia tolerance to Fe deficiency. Further investigations revealed that the expression level of several structural genes involved in Fe uptake in petunia, such as IRT1 and FRO2, was higher in phbhlh121 mutants compared to that in wild-type under Fe-limited conditions, and the expression level of several genes involved in Fe storage and Fe transport, such as VTL2, FERs and ZIF1, was lower in phbhlh121 mutants compared to that in wild-type under Fe-deficient conditions. Yeast one-hybrid assays revealed that PhbHLH121 binds to the G-box element in the promoter of genes involved in Fe homeostasis. Yeast two-hybrid assays revealed that PhbHLH121 interacts with petunia bHLH IVc proteins. Taken together, PhbHLH121 plays an important role in the Fe deficiency response in petunia.<\/jats:p>","DOI":"10.3390\/plants13233429","type":"journal-article","created":{"date-parts":[[2024,12,6]],"date-time":"2024-12-06T06:25:16Z","timestamp":1733466316000},"page":"3429","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":7,"title":["The bHLH Transcription Factor PhbHLH121 Regulates Response to Iron Deficiency in Petunia hybrida"],"prefix":"10.3390","volume":"13","author":[{"given":"Liru","family":"Pan","sequence":"first","affiliation":[{"name":"School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Chengcheng","family":"Huang","sequence":"additional","affiliation":[{"name":"School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ruiling","family":"Li","sequence":"additional","affiliation":[{"name":"School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yanbang","family":"Li","sequence":"additional","affiliation":[{"name":"School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2024,12,6]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"125","DOI":"10.1146\/annurev-arplant-050213-035759","article-title":"Iron cofactor assembly in plants","volume":"65","author":"Balk","year":"2014","journal-title":"Annu. Rev. Plant Biol."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"813","DOI":"10.1039\/C7MT00136C","article-title":"Iron homeostasis in plants-a brief overview","volume":"9","author":"Connorton","year":"2017","journal-title":"Metallomics"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"250","DOI":"10.1016\/S1369-5266(99)80043-0","article-title":"Iron acquisition by plants","volume":"2","author":"Mori","year":"1999","journal-title":"Curr. Opin. Plant Biol."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"1072","DOI":"10.1111\/j.1469-8137.2009.02908.x","article-title":"Dissecting iron deficiency-induced proton extrusion in Arabidopsis roots","volume":"183","author":"Santi","year":"2009","journal-title":"New Phytol."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"1223","DOI":"10.1105\/tpc.001388","article-title":"IRT1, an Arabidopsis transporter essential for iron uptake from the soil and for plant growth","volume":"14","author":"Vert","year":"2002","journal-title":"Plant Cell"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"5624","DOI":"10.1073\/pnas.93.11.5624","article-title":"A novel iron-regulated metal transporter from plants identified by functional expression in yeast","volume":"93","author":"Eide","year":"1996","journal-title":"Proc. Natl. Acad. Sci. USA"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"346","DOI":"10.1038\/35053080","article-title":"Maize yellow stripe1 encodes a membrane protein directly involved in Fe(III) uptake","volume":"409","author":"Curie","year":"2001","journal-title":"Nature"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"786","DOI":"10.1104\/pp.109.135418","article-title":"Disruption of OsYSL15 leads to iron inefficiency in rice plants","volume":"150","author":"Lee","year":"2009","journal-title":"Plant Physiol."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"3400","DOI":"10.1105\/tpc.104.024315","article-title":"Lou 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_10","doi-asserted-by":"crossref","first-page":"528","DOI":"10.1016\/j.febslet.2004.10.062","article-title":"FRU (BHLH029) is required for induction of iron mobilization genes in Arabidopsis thaliana","volume":"577","author":"Jakoby","year":"2004","journal-title":"FEBS Lett."},{"key":"ref_11","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_12","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_13","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_14","doi-asserted-by":"crossref","first-page":"1433","DOI":"10.1111\/nph.15753","article-title":"Transcriptional integration of the responses to iron availability in Arabidopsis by the bHLH factor ILR3","volume":"223","author":"Tissot","year":"2019","journal-title":"New Phytol."},{"key":"ref_15","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_16","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_17","doi-asserted-by":"crossref","first-page":"1795582","DOI":"10.1080\/15592324.2020.1795582","article-title":"Further insights into the role of bHLH121 in the regulation of iron homeostasis in Arabidopsis thaliana","volume":"15","author":"Gao","year":"2020","journal-title":"Plant Signal. Behav."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"24933","DOI":"10.1073\/pnas.1916892116","article-title":"Lou 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_19","doi-asserted-by":"crossref","first-page":"1335","DOI":"10.1093\/plphys\/kiab540","article-title":"bHLH11 inhibits bHLH IVc proteins by recruiting the TOPLESS\/TOPLESS-RELATED corepressors","volume":"188","author":"Li","year":"2022","journal-title":"Plant Physiol."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"93","DOI":"10.1007\/s10265-018-1068-z","article-title":"The basic helix-loop-helix transcription factor, bHLH11 functions in the iron-uptake system in Arabidopsis thaliana","volume":"132","author":"Tanabe","year":"2019","journal-title":"J. Plant Res."},{"key":"ref_21","doi-asserted-by":"crossref","unstructured":"Vandenbussche, M., Chambrier, P., Rodrigues Bento, S., and Morel, P. (2016). Petunia, Your Next Supermodel?. Front. Plant Sci., 7.","DOI":"10.3389\/fpls.2016.00072"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"16074","DOI":"10.1038\/nplants.2016.74","article-title":"Insight into the evolution of the Solanaceae from the parental genomes of Petunia hybrida","volume":"2","author":"Bombarely","year":"2016","journal-title":"Nat. Plants"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"1421","DOI":"10.21273\/HORTSCI.39.6.1421","article-title":"Growth and pigment content of container-grown impatiens and petunia in relation to root substrate pH and applied micronutrient concentration","volume":"39","author":"Smith","year":"2004","journal-title":"HortScience"},{"key":"ref_24","doi-asserted-by":"crossref","unstructured":"Murata, Y., Itoh, Y., Iwashita, T., and Namba, K. (2015). Transgenic petunia with the iron(III)-phytosiderophore transporter gene acquires tolerance to iron deficiency in alkaline environments. PLoS ONE, 10.","DOI":"10.1371\/journal.pone.0120227"},{"key":"ref_25","doi-asserted-by":"crossref","unstructured":"Passeri, V., Li, S., Mart\u00ednez i Calv\u00f3\u2019, E., Senden, E., Guzzo, F., Commisso, M., Spelt, C., Vandenbussche, M., Bliek, M., and Verweij, W. (2023). Role of the metallo-reductase FADING and vacuolinos in anthocyanin degradation in flowers and fruits. bioRxiv.","DOI":"10.1101\/2023.12.21.569356"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"1157","DOI":"10.1111\/tpj.13751","article-title":"A RhABF2\/Ferritin module affects rose (Rosa hybrida) petal dehydration tolerance and senescence by modulating iron levels","volume":"92","author":"Liu","year":"2017","journal-title":"Plant J."},{"key":"ref_27","doi-asserted-by":"crossref","unstructured":"South, K.A., Nordstedt, N.P., and Jones, M.L. (2021). Article identification of plant growth promoting rhizobacteria that improve the performance of greenhouse-grown petunias under low fertility conditions. Plants, 10.","DOI":"10.3390\/plants10071410"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"668","DOI":"10.1016\/j.tplants.2023.11.022","article-title":"The arabidopsis bHLH transcription factor family","volume":"29","author":"Gao","year":"2024","journal-title":"Trends Plant Sci."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"1953","DOI":"10.1105\/tpc.105.032060","article-title":"A basic helix-loop-helix transcription factor in Arabidopsis, MYC2, acts as a repressor of blue light-mediated photomorphogenic growth","volume":"17","author":"Yadav","year":"2005","journal-title":"Plant Cell"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"17584","DOI":"10.1073\/pnas.1907971116","article-title":"Arabidopsis BRUTUS-LIKE E3 ligases negatively regulate iron uptake by targeting transcription factor FIT for recycling","volume":"116","author":"Connorton","year":"2019","journal-title":"Proc. Natl. Acad. Sci. USA"},{"key":"ref_31","doi-asserted-by":"crossref","unstructured":"Wu, J., Li, K., Li, J., Schat, H., and Li, Y. (2021). Transcriptome profiling of Cu stressed petunia petals reveals candidate genes involved in Fe and Cu crosstalk. Int. J. Mol. Sci., 22.","DOI":"10.3390\/ijms222111604"},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"100349","DOI":"10.1016\/j.xplc.2022.100349","article-title":"Iron uptake, signaling, and sensing in plants","volume":"3","author":"Liang","year":"2022","journal-title":"Plant Commun."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"724","DOI":"10.1105\/tpc.111.095042","article-title":"Vacuolar Nicotianamine Has Critical and Distinct Roles under Iron Deficiency and for Zinc Sequestration in Arabidopsis","volume":"24","author":"Wirtz","year":"2012","journal-title":"Plant Cell"},{"key":"ref_34","doi-asserted-by":"crossref","unstructured":"Gollhofer, J., Timofeev, R., Lan, P., Schmidt, W., and Buckhout, T.J. (2014). Vacuolar-Iron-Transporter1-Like proteins mediate iron homeostasis in Arabidopsis. PLoS ONE, 9.","DOI":"10.1371\/journal.pone.0110468"},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"161","DOI":"10.1016\/0005-2728(96)00022-9","article-title":"The ferritins: Molecular properties, iron storage function and cellular regulation","volume":"1275","author":"Harrison","year":"1996","journal-title":"Biochim. Biophys. Acta-Bioenerg."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"1095","DOI":"10.1093\/mp\/ssp041","article-title":"Post-translational regulation of AtFER2 ferritin in response to intracellular iron trafficking during fruit development in Arabidopsis","volume":"2","author":"Ravet","year":"2009","journal-title":"Mol. Plant"},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"400","DOI":"10.1111\/j.1365-313X.2008.03698.x","article-title":"Ferritins control interaction between iron homeostasis and oxidative stress in Arabidopsis","volume":"57","author":"Ravet","year":"2009","journal-title":"Plant J."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"772","DOI":"10.1093\/molbev\/mst010","article-title":"MAFFT multiple sequence alignment software version 7: Improvements in performance and usability","volume":"30","author":"Katoh","year":"2013","journal-title":"Mol. Biol. Evol."},{"key":"ref_39","doi-asserted-by":"crossref","unstructured":"Criscuolo, A., and Gribaldo, S. (2010). BMGE (Block Mapping and Gathering with Entropy): A new software for selection of phylogenetic informative regions from multiple sequence alignments. BMC Evol. Biol., 10.","DOI":"10.1186\/1471-2148-10-210"},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"268","DOI":"10.1093\/molbev\/msu300","article-title":"IQ-TREE: A fast and effective stochastic algorithm for estimating maximum-likelihood phylogenies","volume":"32","author":"Nguyen","year":"2015","journal-title":"Mol. Biol. Evol."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"1188","DOI":"10.1093\/molbev\/mst024","article-title":"Ultrafast approximation for phylogenetic bootstrap","volume":"30","author":"Minh","year":"2013","journal-title":"Mol. Biol. Evol."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"756","DOI":"10.1111\/tpj.15977","article-title":"MsMYB741 is involved in alfalfa resistance to aluminum stress by regulating flavonoid biosynthesis","volume":"112","author":"Su","year":"2022","journal-title":"Plant J."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"2413","DOI":"10.1016\/j.celrep.2017.05.076","article-title":"A Tonoplast P3B-ATPase Mediates Fusion of Two Types of Vacuoles in Petal Cells","volume":"19","author":"Faraco","year":"2017","journal-title":"Cell Rep."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"961","DOI":"10.1016\/j.molp.2016.04.009","article-title":"CRISPR\/Cas9 Platforms for Genome Editing in Plants: Developments and Applications","volume":"9","author":"Ma","year":"2016","journal-title":"Mol. Plant"},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"8293","DOI":"10.1073\/pnas.1402262111","article-title":"Polarization of IRON-REGULATED TRANSPORTER 1 (IRT1) to the plant-soil interface plays crucial role in metal homeostasis","volume":"111","author":"Vert","year":"2014","journal-title":"Proc. Natl. Acad. Sci. USA"},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"1347","DOI":"10.1105\/tpc.001263","article-title":"Lou Expression of the IRT1 metal transporter is controlled by metals at the levels of transcript and protein accumulation","volume":"14","author":"Connolly","year":"2002","journal-title":"Plant Cell"},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"835","DOI":"10.1046\/j.1365-313X.1996.10050835.x","article-title":"Genetic evidence that induction of root Fe(III) chelate reductase activity is necessary for iron uptake under iron deficiency","volume":"10","author":"Yi","year":"1996","journal-title":"Plant J."},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"1585","DOI":"10.1111\/pbi.13325","article-title":"DcMYB113, a root-specific R2R3-MYB, conditions anthocyanin biosynthesis and modification in carrot","volume":"18","author":"Xu","year":"2020","journal-title":"Plant Biotechnol. J."}],"container-title":["Plants"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2223-7747\/13\/23\/3429\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T16:48:33Z","timestamp":1760114913000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2223-7747\/13\/23\/3429"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2024,12,6]]},"references-count":48,"journal-issue":{"issue":"23","published-online":{"date-parts":[[2024,12]]}},"alternative-id":["plants13233429"],"URL":"https:\/\/doi.org\/10.3390\/plants13233429","relation":{},"ISSN":["2223-7747"],"issn-type":[{"value":"2223-7747","type":"electronic"}],"subject":[],"published":{"date-parts":[[2024,12,6]]}}}