Project description:Genes responsive to brassinosteroid were fully investigated using bil1-1D/bzr1-1D mutant which shows constitutive/enhanced response to brassinosteroid. Bil1-1D plants and wild type were treated with Brz (brasinazole) followed with brassinolide or DMSO, respectively.
Project description:Molecular genetic analyses support a central role of BZR1 in Brassinosteroid (BR) regulation of plant development. The dominant bzr1-1D mutation, which stabilizes the BZR1 protein, completely suppresses the de-etiolated phenotype of the null bri1-116 mutant grown in the dark. Using microarray analysis, we identified genes differentially expressed in bri1-116 compared to wild type and genes differentially expressed in the bzr1-1D;bri1-116 double mutant compared to the bri1-116 single mutant. Consistent with the phenotypic suppression of bri1-116 by bzr1-1D, about 80% of the genes affected in bri1-116 were affected oppositely by bzr1-1D
Project description:Molecular genetic analyses support a central role of BZR1 in Brassinosteroid (BR) regulation of plant development. The dominant bzr1-1D mutation, which stabilizes the BZR1 protein, completely suppresses the de-etiolated phenotype of the null bri1-116 mutant grown in the dark. Using microarray analysis, we identified genes differentially expressed in bri1-116 compared to wild type and genes differentially expressed in the bzr1-1D;bri1-116 double mutant compared to the bri1-116 single mutant. Consistent with the phenotypic suppression of bri1-116 by bzr1-1D, about 80% of the genes affected in bri1-116 were affected oppositely by bzr1-1D BZR1 regulated genes were generated from comparing genes differentially expressed by bzr1-1D;bri1-116 and bri1-116. Genes affected by BRI1 were generated from comparing differentially expressed genes of bri1-116 and Col control. ANOVA was used to find genes whose expression was different between bzr1-1D;bri1-116 and bri1-116 or between bri1-116 and Col samples [see Supplementary file below].
Project description:Analysis of brassinosteroid (BR) and auxin effects on gene expression in Arabidopsis roots. Our genomic results indicate that BR and auxin induce largely opposite gene expression responses in primary roots. RNA-Seq for 7-day-old Arabidopsis Col-0, dwf4, bri1-116, and bri1-116;bzr1-1D roots grown on regular medium and treated with brassinolide, auxin or mock solution for 4 hr.
Project description:Brassinosteroid (BR) homeostasis and signaling are crucial for normal growth; and development of plants. BR signaling through cell-surface receptor; kinases and intracellular components leads to dephosphorylation and; accumulation of the nuclear protein BZR1. How BR signaling regulates gene; expression, however, remains unknown. Here we show that BZR1 is a; transcriptional repressor that has a previously unknown DNA binding domain; and binds directly to the promoters of feedback-regulated BR biosynthetic; genes. To identify additional BZR1-regulated genes and to understand the; BR-regulated transcriptional pathways, we examined the effects of bzr1-1D; and det2 mutations on the expression of BR-regulated genes by using the; Arabidopsis full-genome oligo microarray (Affymetrix). Microarray analyses; identified additional potential targets of BZR1 and illustrated, together; with physiological studies, that BZR1 coordinates BR homeostasis and; signaling by playing dual roles in regulating BR biosynthesis and downstream; growth responses.
Project description:The developmental switch from skotomorphogenesis to photomorphogenesis is critical for the survival and growth of plants, but its regulatory mechanism remains unclear. Here, we report that the steroid hormone brassinosteroids (BRs) play crucial roles in the transition from skotomorphogenesis to photomorphogenesis by regulating chlorophyll biosynthesis to promote the greening of etiolated seedlings upon light exposure. Seedlings of BR-deficient mutant det2-1 accumulated excess protochlorophyllide when grown in darkness, resulting in photo-oxidative damage upon exposure to light. Conversely, the gain-of-function mutant bzr1-1D suppressed the protochlorophyllide-accumulated phenotype of det2-1, thereby promoting greening of etiolated seedlings. Genetic analysis indicated that phytochrome-interacting factors (PIFs) were required for BZR1-promoted seedlings greening. Furthermore, we revealed that the GROWTH REGULATING FACTOR 7 (GRF7) and GRF8 were induced by BZR1 and PIF4 to repress the chlorophyll biosynthesis and promote seedling greening. Suppression the functions of GRFs by overexpressing microRNA396a (miR396a) caused the high-accumulated photochlorophyllide in darkness and more serious photobleach upon light exposure. Additionally, BZR1, PIF4 and GRF7 interact with each other and precisely regulate the expression of chlorophyll biosynthetic genes. Our findings revealed an essential role of brassinosteroid in promoting seedling development and survival during the critical initial emergence of seedlings from subterranean darkness to sunlight.
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:To clarify the genome-wide role of the BZR1-BAS complexes in BR-regulated transcriptional activation or repression processes, we conducted RNA-sequencing (RNA-seq) assay using Col, bzr1-1D, brm-1, and bzr1-1D brm-1 seedlings grown on the medium containing 2 ?M PPZ in the dark for five days.
Project description:Brassinosteroid (BR) and gibberellin (GA) promote many similar developmental responses in plants; but their relationship remains unclear. Here we show that BR and GA act interdependently through a direct interaction between the BR-activated BZR1 and GAinactivated DELLA transcription regulators. GA promotion of cell elongation required BR signaling, whereas BR or active BZR1 can suppresssed the GA-deficient dwarf phenotype. DELLAs directly interacted with BZR1 and inhibited BZR1-DNA binding both in vitro and in vivo. Genome-wide analysis defined a BZR1-dependent GA-regulated transcriptome, which is enriched with light-regulated genes and genes involved in cell wall synthesis and photosynthesis/chloroplast. GA promotion of hypocotyl elongation requires both BZR1 and the phytochrome interacting factors (PIFs), as well as their common downstream targets PREs. The results demonstrate that GA releases DELLA-mediated inhibition of BZR1, and that the DELLA-BZR1-PIF4 interaction defines a core transcription module that mediates coordinated growth regulation by GA, BR and light signals. Wild type Arabidopsis and bzr1-1D were grown in media containing 1 uM PAC and 0 or 2 uM PPZ for 4.5 days in dark, then treated with 10 uM GA3 or mock solution for 12 hr. Total RNA was extracted with Spectrum Plant Total RNA Kit (Sigma) and the mRNA sequencing libraries were constructed with barcodes using TruSeqTM RNA Sample Preparation Kit (Illumina). Six barcoded libraries were pooled together and sequenced by Illumina HiSeq2000.