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: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 Arabidopsis seedlings (Columbia ecotype) were grown for 10 d on 1× MS agar-solidified media under long-day conditions (16:8, white light and dark cycle). The seedlings were then transferred to 2 different liquid media containing either 10–7 M 2,4-D or 10–7 M 2,4-D plus 10–6 M brassinazole. After 8 h of treatment, the seedlings were blotted with paper towels to remove excess media and subject to total RNA isolation. Total RNAs isolated from each batch were prepared from 3 replicate seedlings using an RNeasy plant mini kit (Qiagen, Germany).
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.
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) and auxin co-regulate plant growth in a process termed cross-talking. Based on the assumption that their signal transductions are partially shared, inhibitory chemicals for both signal transductions were screened from a commercially-available library. A chemical designated as NJ15 (ethyl 2-[5-(3,5-dichlorophenyl)-1,2,3,4-tetrazole-2-yl]acetate) diminished the growth promotion of both adzuki bean epicotyls and Arabidopsis seedlings, by either the application of BR or auxin. To understand its target site(s), bioassays with a high dependence on either the signal transduction of BR (BR-signaling) or of auxin (AX-signaling), were performed. NJ15 inhibited photomorphogenesis of Arabidopsis seedlings grown in the dark, which mainly depends on BR-signaling, while NJ15 also inhibited their gravitropic responses mainly depending on AX-signaling. On the study for the structure-activity relationships of NJ15 analogues, they showed strong correlations on the inhibitory profiles between BR- and AX-signalings. These correlations imply that NJ15 targets the downstream pathway after the integration of BR- and AX-signals.
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.