The bZIP transcription factor AREB3 mediates FT signalling and floral transition at the Arabidopsis shoot apical meristem.
The floral transition occurs at the shoot apical meristem (SAM) in response to favourable external and internal signals. Among these signals, variations in daylength (photoperiod) act as robust seasonal cues to activate flowering. In Arabidopsis, long-day photoperiods stimulate production in the lea...
| Main Authors: | , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Public Library of Science (PLoS)
2023-05-01
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| Series: | PLoS Genetics |
| Online Access: | https://doi.org/10.1371/journal.pgen.1010766 |
| _version_ | 1797667852491161600 |
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| author | Damiano Martignago Vítor da Silveira Falavigna Alessandra Lombardi He Gao Paolo Korwin Krukowski Massimo Galbiati Chiara Tonelli George Coupland Lucio Conti |
| author_facet | Damiano Martignago Vítor da Silveira Falavigna Alessandra Lombardi He Gao Paolo Korwin Krukowski Massimo Galbiati Chiara Tonelli George Coupland Lucio Conti |
| author_sort | Damiano Martignago |
| collection | DOAJ |
| description | The floral transition occurs at the shoot apical meristem (SAM) in response to favourable external and internal signals. Among these signals, variations in daylength (photoperiod) act as robust seasonal cues to activate flowering. In Arabidopsis, long-day photoperiods stimulate production in the leaf vasculature of a systemic florigenic signal that is translocated to the SAM. According to the current model, FLOWERING LOCUS T (FT), the main Arabidopsis florigen, causes transcriptional reprogramming at the SAM, so that lateral primordia eventually acquire floral identity. FT functions as a transcriptional coregulator with the bZIP transcription factor FD, which binds DNA at specific promoters. FD can also interact with TERMINAL FLOWER 1 (TFL1), a protein related to FT that acts as a floral repressor. Thus, the balance between FT-TFL1 at the SAM influences the expression levels of floral genes targeted by FD. Here, we show that the FD-related bZIP transcription factor AREB3, which was previously studied in the context of phytohormone abscisic acid signalling, is expressed at the SAM in a spatio-temporal pattern that strongly overlaps with FD and contributes to FT signalling. Mutant analyses demonstrate that AREB3 relays FT signals redundantly with FD, and the presence of a conserved carboxy-terminal SAP motif is required for downstream signalling. AREB3 shows unique and common patterns of expression with FD, and AREB3 expression levels are negatively regulated by FD thus forming a compensatory feedback loop. Mutations in another bZIP, FDP, further aggravate the late flowering phenotypes of fd areb3 mutants. Therefore, multiple florigen-interacting bZIP transcription factors have redundant functions in flowering at the SAM. |
| first_indexed | 2024-03-11T20:20:34Z |
| format | Article |
| id | doaj.art-8b19345ff34a4fc1ac037ab1cd6a8bb1 |
| institution | Directory Open Access Journal |
| issn | 1553-7390 1553-7404 |
| language | English |
| last_indexed | 2024-03-11T20:20:34Z |
| publishDate | 2023-05-01 |
| publisher | Public Library of Science (PLoS) |
| record_format | Article |
| series | PLoS Genetics |
| spelling | doaj.art-8b19345ff34a4fc1ac037ab1cd6a8bb12023-10-03T05:31:15ZengPublic Library of Science (PLoS)PLoS Genetics1553-73901553-74042023-05-01195e101076610.1371/journal.pgen.1010766The bZIP transcription factor AREB3 mediates FT signalling and floral transition at the Arabidopsis shoot apical meristem.Damiano MartignagoVítor da Silveira FalavignaAlessandra LombardiHe GaoPaolo Korwin KrukowskiMassimo GalbiatiChiara TonelliGeorge CouplandLucio ContiThe floral transition occurs at the shoot apical meristem (SAM) in response to favourable external and internal signals. Among these signals, variations in daylength (photoperiod) act as robust seasonal cues to activate flowering. In Arabidopsis, long-day photoperiods stimulate production in the leaf vasculature of a systemic florigenic signal that is translocated to the SAM. According to the current model, FLOWERING LOCUS T (FT), the main Arabidopsis florigen, causes transcriptional reprogramming at the SAM, so that lateral primordia eventually acquire floral identity. FT functions as a transcriptional coregulator with the bZIP transcription factor FD, which binds DNA at specific promoters. FD can also interact with TERMINAL FLOWER 1 (TFL1), a protein related to FT that acts as a floral repressor. Thus, the balance between FT-TFL1 at the SAM influences the expression levels of floral genes targeted by FD. Here, we show that the FD-related bZIP transcription factor AREB3, which was previously studied in the context of phytohormone abscisic acid signalling, is expressed at the SAM in a spatio-temporal pattern that strongly overlaps with FD and contributes to FT signalling. Mutant analyses demonstrate that AREB3 relays FT signals redundantly with FD, and the presence of a conserved carboxy-terminal SAP motif is required for downstream signalling. AREB3 shows unique and common patterns of expression with FD, and AREB3 expression levels are negatively regulated by FD thus forming a compensatory feedback loop. Mutations in another bZIP, FDP, further aggravate the late flowering phenotypes of fd areb3 mutants. Therefore, multiple florigen-interacting bZIP transcription factors have redundant functions in flowering at the SAM.https://doi.org/10.1371/journal.pgen.1010766 |
| spellingShingle | Damiano Martignago Vítor da Silveira Falavigna Alessandra Lombardi He Gao Paolo Korwin Krukowski Massimo Galbiati Chiara Tonelli George Coupland Lucio Conti The bZIP transcription factor AREB3 mediates FT signalling and floral transition at the Arabidopsis shoot apical meristem. PLoS Genetics |
| title | The bZIP transcription factor AREB3 mediates FT signalling and floral transition at the Arabidopsis shoot apical meristem. |
| title_full | The bZIP transcription factor AREB3 mediates FT signalling and floral transition at the Arabidopsis shoot apical meristem. |
| title_fullStr | The bZIP transcription factor AREB3 mediates FT signalling and floral transition at the Arabidopsis shoot apical meristem. |
| title_full_unstemmed | The bZIP transcription factor AREB3 mediates FT signalling and floral transition at the Arabidopsis shoot apical meristem. |
| title_short | The bZIP transcription factor AREB3 mediates FT signalling and floral transition at the Arabidopsis shoot apical meristem. |
| title_sort | bzip transcription factor areb3 mediates ft signalling and floral transition at the arabidopsis shoot apical meristem |
| url | https://doi.org/10.1371/journal.pgen.1010766 |
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