Project description:Transcriptome profiles of wild-type (WT), pif4-101, and transgenic plants expressing the coding region of PIF4 under the control of its endogenous promoter (H71 and H76; pif4-101 mutant background) grown for 3 days in the dark at 22ºC and then, for 3 additional hours, exposed or not to heat stress (37ºC).
Project description:Plant growth is coordinately regulated by environmental and hormonal signals. Brassinosteroid (BR) plays essential roles in growth regulation by light and temperature, but the interactions between BR and these environmental signals remain poorly understood at the molecular level. Here, we show that direct interaction between the dark- and heat-activated transcription factor phytochrome-interacting factor4 (PIF4) and the BR-activated transcription factor BZR1 integrates the hormonal and environmental signals. BZR1 and PIF4 interact with each other in vitro and in vivo, bind to nearly two thousand common target genes, and synergistically regulate many of these target genes, including the PRE family HLH factors required for promoting cell elongation. Genetic analysis indicates that BZR1 and PIFs are interdependent in promoting cell elongation in response to BR, darkness, or heat. These results show that the BZR1-PIF4 interaction controls a core transcription network, allowing plant growth co-regulation by the steroid and environmental signals. Genome-wide identification of PIF4 binding sites in etiolated Arabidopsis seedlings.
Project description:Plant growth is coordinately regulated by environmental and hormonal signals. Brassinosteroid (BR) plays essential roles in growth regulation by light and temperature, but the interactions between BR and these environmental signals remain poorly understood at the molecular level. Here, we show that direct interaction between the dark- and heat-activated transcription factor phytochrome-interacting factor4 (PIF4) and the BR-activated transcription factor BZR1 integrates the hormonal and environmental signals. BZR1 and PIF4 interact with each other in vitro and in vivo, bind to nearly two thousand common target genes, and synergistically regulate many of these target genes, including the PRE family HLH factors required for promoting cell elongation. Genetic analysis indicates that BZR1 and PIFs are interdependent in promoting cell elongation in response to BR, darkness, or heat. These results show that the BZR1-PIF4 interaction controls a core transcription network, allowing plant growth co-regulation by the steroid and environmental signals. RNA-Seq for Col-0, bzr1-1D, pifq and pifq;bzr1-1D seedlings grown on BRZ-containing medium in the dark.
Project description:Plant growth is coordinately regulated by environmental and hormonal signals. Brassinosteroid (BR) plays essential roles in growth regulation by light and temperature, but the interactions between BR and these environmental signals remain poorly understood at the molecular level. Here, we show that direct interaction between the dark- and heat-activated transcription factor phytochrome-interacting factor4 (PIF4) and the BR-activated transcription factor BZR1 integrates the hormonal and environmental signals. BZR1 and PIF4 interact with each other in vitro and in vivo, bind to nearly two thousand common target genes, and synergistically regulate many of these target genes, including the PRE family HLH factors required for promoting cell elongation. Genetic analysis indicates that BZR1 and PIFs are interdependent in promoting cell elongation in response to BR, darkness, or heat. These results show that the BZR1-PIF4 interaction controls a core transcription network, allowing plant growth co-regulation by the steroid and environmental signals.
Project description:Plant growth is coordinately regulated by environmental and hormonal signals. Brassinosteroid (BR) plays essential roles in growth regulation by light and temperature, but the interactions between BR and these environmental signals remain poorly understood at the molecular level. Here, we show that direct interaction between the dark- and heat-activated transcription factor phytochrome-interacting factor4 (PIF4) and the BR-activated transcription factor BZR1 integrates the hormonal and environmental signals. BZR1 and PIF4 interact with each other in vitro and in vivo, bind to nearly two thousand common target genes, and synergistically regulate many of these target genes, including the PRE family HLH factors required for promoting cell elongation. Genetic analysis indicates that BZR1 and PIFs are interdependent in promoting cell elongation in response to BR, darkness, or heat. These results show that the BZR1-PIF4 interaction controls a core transcription network, allowing plant growth co-regulation by the steroid and environmental signals.
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.
Project description:To investigate the effect of the interaction between the MRG1/2 and PIF4, here we analysed differentially expressed genes compared to the mutant and wild-type by RNA-seq under different temperature. We performed gene expression profiling analysis using data obtained from RNA-seq of WT, mrg1 mrg2, pif4, and mrg1 mrg2 pif4 plants at 22degC and 28degC.