The epidermis coordinates thermoresponsive growth through the phyB-PIF4-auxin pathway
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ABSTRACT:
PROVIDER: PRJNA551939 | ENA |
REPOSITORIES: ENA
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Project description:In plants, an elevation in ambient temperature induces morphological changes including elongation hypocotyls, considered to be adaptive responses to alleviate the heat-induced damages. The high temperature-induced morphological changes are called thermomorphogenesis, which is predominantly regulated by a bHLH transcription factor PIF4. Although PIF4 is expressed in all aerial tissues including the epidermis, mesophyll, and vascular bundle, its tissue-specific functions in thermomorphogenesis are not known. Here, we found that epidermis-specific expression of PIF4 induced constitutive long hypocotyls, while vasculature-specific expression of PIF4 had no effect on hypocotyl growth. Consistently, RNA-Seq and qRT-PCR analyses revealed that auxin responsive genes and growth-related genes were highly activated by epidermal, but not by vascular, PIF4. The epidermal, but not vascular, inactivation of PIF4 by a PIF4 artificial microRNA or a dominant negative form of PIF4 suppressed thermoresponsive gene expression and hypocotyl growth. Additionally, both the block of epidermal auxin signaling and the epidermal overexpression of a thermosensor phytochrome B (phyB) inhibited thermoresponsive growth, indicating that epidermal PIF4-auxin pathway are essential for the temperature responses. We further show that epidermal PIF4 is increased by high temperatures mainly through the transcriptional activation of PIF4. Taken together, our study demonstrates that the epidermis regulates thermoresponsive growth through the phyB-PIF4-auxin pathway.
2020-01-26 | GSE133564 | GEO
Project description: Not available
| S-EPMC7044213 | biostudies-literature
Project description:Auxin is a major plant hormone for both development and environmental adaptation. Auxin responses are context dependent and highly modulated by light, temperature, the circadian clock, brassinosteroid, and gibberellin, but the underlying mechanisms remain unclear. Here, we show that auxin signaling integrates with other signals through direct interactions of AUXIN RESPONSE FACTOR6 (ARF6) with PHYTOCHROME INTERACTING FACTOR4 (PIF4), the brassinosteroid-signaling transcription factor BZR1, and the gibberellin-signaling repressor RGA. ChIP-Seq and RNA-Seq experiments show that ARF6, PIF4, and BZR1 bind to largely overlapping targets in the genome and synergistically activate gene expression. In vitro and in vivo assays show that ARF6-promoter binding is enhanced by PIF4 and BZR1 but blocked by RGA. Furthermore, a tripartite HLH/bHLH module feedback regulates PIF activity and thus modulates auxin sensitivity according to additional developmental and environmental cues. Our results demonstrate a central growth-regulation transcriptional network that coordinates hormonal, environmental, and developmental control of cell elongation and plant growth. Genome-wide identification of ARF6 DNA-binding sites in etiolated Arabidopsis seedlings.
2014-06-03 | E-GEOD-51770 | biostudies-arrayexpress
Project description:Auxin is a major plant hormone for both development and environmental adaptation. Auxin responses are context dependent and highly modulated by light, temperature, the circadian clock, brassinosteroid, and gibberellin, but the underlying mechanisms remain unclear. Here, we show that auxin signaling integrates with other signals through direct interactions of AUXIN RESPONSE FACTOR6 (ARF6) with PHYTOCHROME INTERACTING FACTOR4 (PIF4), the brassinosteroid-signaling transcription factor BZR1, and the gibberellin-signaling repressor RGA. ChIP-Seq and RNA-Seq experiments show that ARF6, PIF4, and BZR1 bind to largely overlapping targets in the genome and synergistically activate gene expression. In vitro and in vivo assays show that ARF6-promoter binding is enhanced by PIF4 and BZR1 but blocked by RGA. Furthermore, a tripartite HLH/bHLH module feedback regulates PIF activity and thus modulates auxin sensitivity according to additional developmental and environmental cues. Our results demonstrate a central growth-regulation transcriptional network that coordinates hormonal, environmental, and developmental control of cell elongation and plant growth. Seedlings (Col-0 and iaa3) were grown on medium containing 2 µM propiconazole (PPZ) in the dark for 5 days and treated with mock or 100 nM BL for 4 hr before harvesting for total RNA extraction.
2014-06-03 | E-GEOD-51772 | biostudies-arrayexpress
Project description:Auxin is a major plant hormone for both development and environmental adaptation. Auxin responses are context dependent and highly modulated by light, temperature, the circadian clock, brassinosteroid, and gibberellin, but the underlying mechanisms remain unclear. Here, we show that auxin signaling integrates with other signals through direct interactions of AUXIN RESPONSE FACTOR6 (ARF6) with PHYTOCHROME INTERACTING FACTOR4 (PIF4), the brassinosteroid-signaling transcription factor BZR1, and the gibberellin-signaling repressor RGA. ChIP-Seq and RNA-Seq experiments show that ARF6, PIF4, and BZR1 bind to largely overlapping targets in the genome and synergistically activate gene expression. In vitro and in vivo assays show that ARF6-promoter binding is enhanced by PIF4 and BZR1 but blocked by RGA. Furthermore, a tripartite HLH/bHLH module feedback regulates PIF activity and thus modulates auxin sensitivity according to additional developmental and environmental cues. Our results demonstrate a central growth-regulation transcriptional network that coordinates hormonal, environmental, and developmental control of cell elongation and plant growth.
2014-06-03 | GSE51772 | GEO
Project description:Auxin is a major plant hormone for both development and environmental adaptation. Auxin responses are context dependent and highly modulated by light, temperature, the circadian clock, brassinosteroid, and gibberellin, but the underlying mechanisms remain unclear. Here, we show that auxin signaling integrates with other signals through direct interactions of AUXIN RESPONSE FACTOR6 (ARF6) with PHYTOCHROME INTERACTING FACTOR4 (PIF4), the brassinosteroid-signaling transcription factor BZR1, and the gibberellin-signaling repressor RGA. ChIP-Seq and RNA-Seq experiments show that ARF6, PIF4, and BZR1 bind to largely overlapping targets in the genome and synergistically activate gene expression. In vitro and in vivo assays show that ARF6-promoter binding is enhanced by PIF4 and BZR1 but blocked by RGA. Furthermore, a tripartite HLH/bHLH module feedback regulates PIF activity and thus modulates auxin sensitivity according to additional developmental and environmental cues. Our results demonstrate a central growth-regulation transcriptional network that coordinates hormonal, environmental, and developmental control of cell elongation and plant growth.
2014-06-03 | GSE51770 | GEO
Project description:Seedling hypocotyls display negative gravitropism in the dark but agravitropism in the light. The Arabidopsis thaliana pif quadruple mutant (pifQ), which lacks four PHYTOCHROME-INTERACTING FACTORS (PIFs), is agravitropic in the dark. Endodermis-specific expression of PIF1 rescues gravitropism in pifQ mutant seedlings. Since phytochromes induce light responses by inhibiting PIFs and the COP1-SPA ubiquitin E3 ligase complex in the nucleus, we asked whether phyB can cell autonomously inhibit hypocotyl negative gravitropism in the endodermis. We found that while epidermis-specific expression of PHYB rescues hypocotyl negative gravitropism and all other phyB mutant phenotypes, endodermis-specific expression of PHYB does not. Epidermal phyB induces the phosphorylation and degradation of endodermal PIFs in response to red light. This induces a global gene expression pattern similar to that induced by red light treatment of seedlings expressing PHYB under the control of its own endogenous promoter. Our results imply that epidermal phyB generates an unidentified mobile signal that travels to the endodermis where it promotes PIF degradation and inhibits hypocotyl negative gravitropism.
2017-02-08 | GSE87591 | GEO
Project description:Growth of a complex multicellular organism requires coordinated changes in diverse cell types. These cellular changes generate organs of the correct size, shape and functionality. During plant development, the growth hormone auxin induces stem elongation; however, which cell types of the stem perceive the auxin signal and contribute to organ growth is poorly understood. Here, we show that auxin signalling is required in many cell types for correct hypocotyl stem growth, with a key role for the epidermis. Combining genetic manipulations in Arabidopsis thaliana with transcriptional profiling of the hypocotyl epidermis from Brassica rapa, we show that auxin functions in the epidermis in part by inducing activity of the locally-acting, growth-promoting brassinosteroid pathway. Our findings clarify cell-specific auxin function in the hypocotyl, and highlight the complexity of cell-type interactions within a growing organ.
2016-06-30 | GSE79881 | GEO
Project description:Growth of a complex multicellular organism requires coordinated changes in diverse cell types. These cellular changes generate organs of the correct size, shape and functionality. During plant development, the growth hormone auxin induces stem elongation; however, which cell types of the stem perceive the auxin signal and contribute to organ growth is poorly understood. Here, we show that auxin signalling is required in many cell types for correct hypocotyl stem growth, with a key role for the epidermis. Combining genetic manipulations in Arabidopsis thaliana with transcriptional profiling of the hypocotyl epidermis from Brassica rapa, we show that auxin functions in the epidermis in part by inducing activity of the locally-acting, growth-promoting brassinosteroid pathway. Our findings clarify cell-specific auxin function in the hypocotyl, and highlight the complexity of cell-type interactions within a growing organ. We performed whole-genome transcriptome (mRNA-Seq) on 5 d-old W light-grown Arabidopsis thaliana plants (CER6pro>>axr3-1::mCit experimental plants and UAS::axr3-1::mCit hemizygous control plants; whole-seedling tissue) treated for 4 h W light or low R:FR shade. In addition, we performed mRNA-Seq on 4 d-old Brassica rapa plants (FPsc strain) treated for 9 h W light or shade. Brassica tissues collected were hypocotyl epidermal peels or whole hypocotyls.
2016-06-30 | E-GEOD-79881 | biostudies-arrayexpress
Project description:Warm ambient temperatures do not trigger stress responses in plants but stimulate the growth of specific organs. The basic helix-loop-helix transcription factor PHYTOCHROME-INTERACTING FACTOR 4 (PIF4) plays a central role in regulating thermomorphogenetic hypocotyl elongation in various plant species, including the model dicotyledonous plant Arabidopsis thaliana. Although it is well known that PIF4 promotes plant thermosensory growth by activating key genes involved in the biosynthesis and signaling of the phytohormone auxin, the detailed molecular mechanism of such transcriptional activation is still not clear. Our previous studies demonstrated that HEMERA (HMR), a transcription co-activator of PIF4, promotes the thermo-induced expression of PIF4 target genes through the nine-amino-acid transactivation domain (9aaTAD) in its carboxy-terminus. In this report, we investigate the role of the Mediator complex in the PIF4/HMR-mediated thermoresponsive gene expression. Through the characterization of various mutants of the Mediator complex, a tail subunit named MED14 is identified as an essential factor for thermomorphogenetic hypocotyl growth. MED14 is required for the thermal induction of key PIF4 target genes but has a marginal effect on the levels of PIF4 and HMR. Further transcriptomic analyses confirm that the expression of numerous PIF4/HMR-dependent, auxin-related genes requires MED14 at a warm temperature. Moreover, PIF4 and HMR physically interact with MED14 and both are indispensable for the association of MED14 with the promoters of these thermoresponsive genes. Together, these results unveil an important thermomorphogenetic mechanism, in which PIF4 and its coactivator HMR recruit the Mediator complex to activate auxin-related growth-promoting genes when plants sense moderate increases in ambient temperature.
2022-09-26 | GSE196969 | GEO