Project description:Understanding how developmental and environmental signals are integrated to produce specific responses is one of the main challenges of modern biology. Hormones and, most importantly, interactions between different hormones serve as crucial regulators of plant growth and development, playing central roles in the coordination of internal developmental processes with the environment. Herein, a combination of physiological, genetic, cellular, and whole-genome expression profiling approaches has been employed to investigate the mechanisms of interaction between two key plant hormones, ethylene and auxin. Quantification of the morphological effects of ethylene and auxin in a variety of mutant backgrounds indicates that auxin biosynthesis, transport, signaling and response are required for the ethylene-induced growth inhibition in roots but not in hypocotyls. Analysis of the activation of early auxin and ethylene responses at cellular level, as well as of global changes in gene expression in the wild type versus auxin and ethylene mutants, suggests a simple mechanistic model for the interaction between these two hormones in roots. This model not only implies existence of several levels of interaction but also provides a likely explanation for the strong ethylene response defects observed in auxin mutants. Experiment Overall Design: The effect of ethylene on gene expression in Col-0 (wild-type) and aux1-7 (an auxin resistant mutant) seedlings' roots was investigated. Hydrocarbon-free air was used as control for the ethylene treatment. Two biological replicates were examined. Experiment Overall Design: Similarly, the effect of auxin (IAA) on gene expression in Col (wild-type) and ein2-5 (an ethylene insensitive mutant) seedlings' roots was studied. Two biological replicates were employed.
Project description:Transcriptional profiling of Arabidopsis thaliana seedlings treated with auxin (indole-3-acetic acid), highlighting to the physiological function of auxin by observing early response of gene expressions in Arabidopsis seedlings.
Project description:We found that auxin stimulates gene expression of DWF4, which encodes a rate-dertermining step in brassinosteroid biosynthesis pathways. This increased gene expressioin subsequently led to elevation of the biosynthetic flux in Arabidopsis roots. To determine the list of genes that are regulated by auxin-synthesizing brassinosteroids, we challenged Arabidopsis seedlings with either auxin only or auxin plus brassinosteroid biosynthetic inhibitor brassinazole. Keywords: Hormone treatment
Project description:Transcriptional profiling of Arabidopsis thaliana seedlings treated with auxin (indole-3-acetic acid), highlighting to the physiological function of auxin by observing early response of gene expressions in Arabidopsis seedlings. Two-condition experiment, auxin-treated seedlings vs. control seedlings. Biological replicates:2 control replicates, 2 auxin-treated.
Project description:Ethylene-dependent gene expression was assayed by treating with 1 uM ACC, an ethylene precursor, or a control treatment to Arabidopsis seedlings by transferring 6 day old Arabidopsis grown on a a nylon mesh to fresh ACC-containing or control media Seedling roots were harvested 0, .5, 1, 2, 4, 8, 12, and 24 hours after treatment and the resultant RNA was used for microarray analysis to determine the kinetic profiles of auxin-responsive gene expression
Project description:Understanding how developmental and environmental signals are integrated to produce specific responses is one of the main challenges of modern biology. Hormones and, most importantly, interactions between different hormones serve as crucial regulators of plant growth and development, playing central roles in the coordination of internal developmental processes with the environment. Herein, a combination of physiological, genetic, cellular, and whole-genome expression profiling approaches has been employed to investigate the mechanisms of interaction between two key plant hormones, ethylene and auxin. Quantification of the morphological effects of ethylene and auxin in a variety of mutant backgrounds indicates that auxin biosynthesis, transport, signaling and response are required for the ethylene-induced growth inhibition in roots but not in hypocotyls. Analysis of the activation of early auxin and ethylene responses at cellular level, as well as of global changes in gene expression in the wild type versus auxin and ethylene mutants, suggests a simple mechanistic model for the interaction between these two hormones in roots. This model not only implies existence of several levels of interaction but also provides a likely explanation for the strong ethylene response defects observed in auxin mutants. Keywords: Genetic modification. Plant hormone response
Project description:We performed an analysis of transcriptomic responses to auxin within four distinct tissues of the Arabidopsis thaliana root. This high-resolution dataset shows how different cell types are predisposed to react to auxin with discrete transcriptional responses. The sensitivity provided by the analysis lies in the ability to detect cell-type specific responses diluted in organ-level analyses. This dataset provides a novel resource to examine how auxin, a widespread signal in plant development, influences differentiation and patterning in the plant through tissue-specific transcriptional regulation. To analyze the effect of auxin in separate spatial domains of the root, early transcriptional changes in response to auxin treatment were assayed by means of fluorescence activated cell sorting (FACS) and microarray analysis in four tissues of the Arabidopsis root (wild type Col-0). The samples covered inner and outer as well as proximal and distal cell populations; including the stele (reporter line pWOL::GFP), xylem-pole (xp) pericycle (enhancer trap line E3754), epidermis/lateral root cap (reporter line pWER::GFP) and columella (enhancer trap line PET111). One-week-old seedlings of the individual lines were treated with auxin (two hours, 5µM indole-3-acetic acid [IAA]) or mock treated, after which roots were harvested and cells were dissociated by cell wall digestion (1 hour; including 5uM IAA) . GFP-positive cells were sorted and used for microarray transcriptome analysis (as in Bargmann and Birnbaum, Plant Phys. 2010). For comparison, transcriptional responses to auxin were also assayed in intact (undigested) roots.