Project description:This SuperSeries is composed of the following subset Series:; GSE10496: Expression analysis of the effect of protoplasting and FACS sorting in roots exposed to iron deficiency (-Fe); GSE10497: Expression analysis of root developmental zones after iron deficiency (-Fe) treatment; GSE10501: Expression analysis of root cell-types after iron deficiency (-Fe) treatment; GSE10502: Time course expression analysis of the iron deficiency (-Fe) response in Arabidopsis roots Experiment Overall Design: Refer to individual Series
Project description:In order to estimate the effects of protoplasting and FACS sorting procedures on -Fe regulated gene expression we generated expression profiles for whole roots that had been treated with -Fe for 24 hours and for roots that were protoplasted and FACS sorted after the initial 24 hour -Fe treatment. Little is known about how developmental cues affect the way cells interpret their environment. Here we characterize the transcriptional response of different cell layers and developmental stages of the Arabidopsis root to high salinity and find that transcriptional responses are highly constrained by developmental parameters. These transcriptional changes lead to the differential regulation of specific biological functions in subsets of cell-layers, several of which correspond to observable physiological changes. We show that known stress pathways primarily control semi-ubiquitous responses and use mutants that disrupt epidermal patterning to reveal cell-layer specific and inter-cell-layer effects. By performing a similar analysis using iron-deprivation we identify common cell-type specific stress responses and environment-independent biological functions that define each cell type. Experiment Overall Design: To estimate the effect that protoplasting and cell sorting has on the expression of -Fe regulated genes we prepared samples as in Birnbaum et al. (2005) Nat. Methods, except that all cells were collected after cell sorting. Cells were collected from roots that had been exposed to iron deficient (-Fe) conditions (0.3mM Ferrozine in MS media containing no ferrous sulfate) for 24 hours prior to protoplasting. Whole roots were also collected after a similar treatment regimen with -Fe. Three replicates were performed per condition.
Project description:In order to estimate the effects of protoplasting and FACS sorting procedures on -Fe regulated gene expression we generated expression profiles for whole roots that had been treated with -Fe for 24 hours and for roots that were protoplasted and FACS sorted after the initial 24 hour -Fe treatment. Little is known about how developmental cues affect the way cells interpret their environment. Here we characterize the transcriptional response of different cell layers and developmental stages of the Arabidopsis root to high salinity and find that transcriptional responses are highly constrained by developmental parameters. These transcriptional changes lead to the differential regulation of specific biological functions in subsets of cell-layers, several of which correspond to observable physiological changes. We show that known stress pathways primarily control semi-ubiquitous responses and use mutants that disrupt epidermal patterning to reveal cell-layer specific and inter-cell-layer effects. By performing a similar analysis using iron-deprivation we identify common cell-type specific stress responses and environment-independent biological functions that define each cell type. Keywords: effects of protoplasting and FACS sorting
Project description:This SuperSeries is composed of the following subset Series: GSE30091: Expression analysis of the effect of protoplasting and sorting in roots exposed to low pH GSE30095: Expression analysis of root cell types after treatment with low pH GSE30096: Expression analysis of developmental stages of Arabidopsis roots exposed to low pH GSE30097: Time-course expression analysis of the low pH (pH 4.6) response in Arabidopsis whole roots GSE30098: Expression analysis time-course of Arabidopsis roots to sulfur deficiency GSE30099: Expression analysis of root cell types after treatment with sulfur deficient media GSE30100: Expression analysis of developmental stages of Arabidopsis roots exposed to sulfur deficient media GSE30104: Genome-wide identification of SCARECROW (SCR) direct targets using a custom Agilent promoter array Refer to individual Series
Project description:Pericycle specific transcriptional profiles were generated by FACS (Fluorescence Activated Cell Sorting) of roots that express a pericycle-specific GFP-reporter. FACS cell populations were isolated from roots grown under standard conditions or roots that had been transferred to -Fe media for 24 hours. Global population increases and climate change underscore the need for better comprehension of how plants acquire and process nutrients such as iron. A systems biology approach was taken to elucidate novel regulatory mechanisms involved in plant responses to iron deficiency (-Fe). Using cell-type specific transcriptional profiling we identified a pericycle-specific iron deficiency response, and a previously uncharacterized transcription factor, POPEYE (PYE), that plays an important role in this response. Functional analysis of PYE suggests that it positively regulates growth and development under iron deficient conditions. ChIP-on-chip analysis and transcriptional profiling reveal that PYE helps maintain iron homeostasis by directly and indirectly regulating the expression of ferric reductases, metal ion transporters, iron storage proteins, and other key iron homeostasis genes. In addition to PYE, we also identified a second protein BRUTUS (BTS), which appears to negatively regulate the response to iron deficiency. BTS is a unique putative E3 ligase protein, with metal ion binding and DNA binding domains. PYE and BTS are tightly co-regulated and physically interact with PYE paralogs, one of which is thought to positively regulate expression of genes involved in iron homeostasis. We propose that iron content is sensed within the pericycle where PYE, perhaps in conjunction with BTS and other regulatory proteins, is then activated to control a regulatory network involved in maintaining proper iron distribution in plants. Keywords: Cell-type specific analysis of stress response using FACS
Project description:Iron (Fe) plays a pivotal role in several metabolic and biosynthetic pathways essential for plant growth. Fe deficiency in plants severely affects the overall crop yield. Despite several studies on iron deficiency responses in different plant species, these mechanisms remain unclear in the allohexaploid wheat, which is the most widely cultivated commercial crop. In order to gain a comprehensive insight into molecular responses of bread wheat when exposed to iron deficiency, we studied transcriptomic changes in the roots and flag leaves of wheat plants subjected to iron-deficient and iron-sufficient conditions during early grain filling.
Project description:Cell-type specific transcriptional profiles were generated by FACS (Fluorescence Activated Cell Sorting) sorting of roots that express cell-type specific GFP-reporters. Five different GFP-reporter lines were utilized allowing us to obtain transcriptional profiles for cells in all radial zones of the root. FACS cell populations were isolated from roots grown under standard conditions or roots that had been transfered to -Fe media for 24 hours. Little is known about how developmental cues affect the way cells interpret their environment. Here we characterize the transcriptional response of different cell layers and developmental stages of the Arabidopsis root to high salinity and find that transcriptional responses are highly constrained by developmental parameters. These transcriptional changes lead to the differential regulation of specific biological functions in subsets of cell-layers, several of which correspond to observable physiological changes. We show that known stress pathways primarily control semi-ubiquitous responses and use mutants that disrupt epidermal patterning to reveal cell-layer specific and inter-cell-layer effects. By performing a similar analysis using iron-deprivation we identify common cell-type specific stress responses and environment-independent biological functions that define each cell type. Experiment Overall Design: To gain a genome-scale understanding of the role that developmental processes play in regulating stimulus response, we examined the effect of -Fe stress on gene expression along the radial axis of the root. Cell identity is the main variable that changes along the radial axis with the epidermis representing the outermost tissue layer and the stele representing the inner most layer. 5 different GFP reporter lines were used to isolate specific populations of cells from the Arabidopsis root using FACS sorting of protoplasted cells. GFP-reporter lines were exposed to iron deficient (-Fe) conditions (0.3mM Ferrozine in MS media containing no ferrous sulfate) for 24 hours before hand.