Project description:Transcriptional profiling of hypocotyl comparing wild type with shr mutant. We used Affymetrix ATH1 microarrays to determine the effect of GRAS transcription factor SHORT-ROOT on growth and development of Arabidopsis shoot system (hypocotyl) by global transcriptome analysis and to identify the key players in the regulatory pathway.
Project description:We found that Arabidopsis plants constitutively expressing OsRR6 exhibit reduced cytokinin sensitivity, adventitious root formation and enhanced anthocyanin accumulation. In addition they are hypersensitive to red, far-red and blue light in hypocotyl growth assay and also flower little early as compared to wild type.Therefore, to identify the downstream pathways affected in the OsRR6 overexpression plants, we performed transcriptome profiling of overexpression line vs wild type using Affymetrix microarray platform.
Project description:A chemical screen was performed in search of compounds that modify plant responses to sucrose. This screen uncovered that sulfamethoxazole (SMX), a folate biosynthesis inhibitor, acted synergistically with sucrose to inhibit hypocotyl elongation, suggesting interaction between these two pathways. Transcriptome analysis was performed to identify changes in transcript abundance that may underpin crosstalk between sucrose and SMX. Three-day-old dark-grown seedlings were treated to sucrose and SMX at concentrations that induced no change in hypocotyl elongation when administered independently, yet restricted elongation when both were present in the growth media (10mM and 0.2µM, respectively). This analysis uncovered multiple core auxin signalling components that exhibit altered transcript abundance in response to co-treatment with sucrose and SMX, suggesting that auxin signalling mediates crosstalk between these two pathways. This study highlights an input through which metabolic status can shape plant growth and development through hormone signalling.
Project description:Plants have evolved shoot elongation mechanisms to escape from diverse environmental stresses such as flooding and vegetative shade. The apparent similarity in growth responses suggests possible convergence of the signalling pathways. Shoot elongation is mediated by passive ethylene accumulating in flooded plant organs and by changes in light quality and quantity under vegetation shade. Here we study hypocotyl elongation as a proxy for shoot elongation and delineated Arabidopsis hypocotyl length kinetics in response to ethylene and shade. Based on these kinetics, we further investigated ethylene and shade-induced genome-wide gene expression changes in hypocotyls and cotyledons separately. Both treatments induced a more extensive transcriptome reconfiguration in the hypocotyls compared to the cotyledons. Bioinformatics analyses suggested contrasting regulation of growth promotion- and photosynthesis-related genes. These analyses also suggested an induction of auxin, brassinosteroid and gibberellin signatures and the involvement of several candidate regulators in the elongating hypocotyls. Pharmacological and mutant analyses confirmed the functional involvement of several of these candidate genes and physiological control points in regulating stress-escape responses to different environmental stimuli. We discuss how these signaling networks might be integrated and conclude that plants, when facing different stresses, utilise a conserved set of transcriptionally regulated genes to modulate and fine tune growth. 1 day old Arabidopsis seedlings were subjected to control, ethylene and shade conditions. Hypocotyl and cotyledon tissues were harvested at 1.5 h, 13.5 h and 25.5 h of treatment time respectively. Microarray hybridization was carried out with 3 biological replicates (collected over 3 independent experiments) of each sample using the Affymetrix Arabidopsis Gene 1.1 ST platform.
Project description:A chemical screen was performed in search of compounds that modify plant responses to sucrose. This screen uncovered that sulfamethoxazole (SMX), a folate biosynthesis inhibitor, acted synergistically with sucrose to inhibit hypocotyl elongation, suggesting interaction between these two pathways. Transcriptome analysis was performed to identify changes in transcript abundance that may underpin crosstalk between sucrose and SMX. Three-day-old dark-grown seedlings were treated to sucrose and SMX at concentrations that induced no change in hypocotyl elongation when administered independently, yet restricted elongation when both were present in the growth media (10mM and 0.2µM, respectively). This analysis uncovered multiple core auxin signalling components that exhibit altered transcript abundance in response to co-treatment with sucrose and SMX, suggesting that auxin signalling mediates crosstalk between these two pathways. This study highlights an input through which metabolic status can shape plant growth and development through hormone signalling. 12 arrays total. Three arrays as non-treated control, three arrays from seedlings raised in presence of 0.2µM SMX, three arrays from seedlings raised in presence of 10mM sucrose, and three arrays from seeldings raised in presence of both 10mM sucrose and 0.2µM SMX. Three biological replicates were produced for each growth treatment.
Project description:We report POWERDRESS (PWR), a SANT domain containing protein known to facilitate the deacetylation of lysine rich residues of histone H3 by HISTONE DEACETYLASE 9 (HDA9), to play key role in temperature induced growth in Arabidopsis thaliana. Mutations in PWR showed severe attenuation in high temperature associated phenotypes viz., temperature-induced hypocotyl elongation, petiole elongation and early flowering. The study involved analysing the impact of the loss of PWR on the transcriptome in response to changes in ambient temperature. About one hundred 6 day old seedlings of wild type (Col-0) and pwr-2 mutant (in Col-0 background) were grown at 23 °C in short days (SD) photoperiod in growth chambers (GR-36, Percival Scientific, Canada). Half of the samples were then shifted to 27°C under short day photoperiod. Total RNA was extracted from whole seedlings grown at 23 °C and 27°C after two hours. Two biological replicates were used for Col-0 and pwr-2 samples. RNA was extracted using Isolate II RNA plant kit (Bioline Pty Ltd, Australia). RNA-Seq libraries were generated on Illumina HiSeqTM 2000 platform using paired-end sequencing of 90 bp in length at BGI-Shenzen (Beijing Genomics Institute). Gene expression analysis was performed using DESeq2 (v1.14.1) differential expression analysis pipeline.
Project description:The time between seed germination and the development of the first true leaves is crucial for plants success. Depending on the environmental light conditions a plant must decide which developmental program to use. If light is limited, the seedling will use etiolated growth characterized by an elongated hypocotyl and tightly-closed, underdeveloped cotyledons, thus allowing it to reach a light source as quickly as possible. In contrast, seedlings that are grown in unlimited light will use de-etiolation growth, that is characterized by inhibited hypocotyl growth and unhooked, unfolded and fully expanded cotyledons. These seedlings become photosynthetic and increase their chances for reproduction. Interestingly, the outcome of the light signal varies between the seedling’s different organs, e.g. hypocotyl growth is inhibited by light whereas cotyledon expansion is induced. Separating the cotyledons and hypocotyls of de-etiolated seedlings during their first 12 hours of white light exposure, enabled us to perform individual transcriptome analyses of each organ and to examine what causes this variation in light responsiveness.