Project description:Low reduced red:far-red ratio [R:FR] signaling through phytochromes induces shade avoidance responses, including petiole elongation. Jasmonic acid-mediated defense against herbivores and pathogens is inhibited under these conditions. Using microarrays we studied the crosstalk between low R:FR and JA at the global gene expression level in Arabidopsis thaliana. Plants were exposed for 2 h. to the following treatments: high R/FR with mock spray, low R/FR with mock spray, high R/FR with JA spray, low R/FR with JA spray. Gene expression was determined in petioles.
Project description:Low reduced red:far-red ratio [R:FR] signaling through phytochromes induces shade avoidance responses, including petiole elongation. Jasmonic acid-mediated defense against herbivores and pathogens is inhibited under these conditions. Using microarrays we studied the crosstalk between low R:FR and JA at the global gene expression level in Arabidopsis thaliana.
Project description:The goal of this work was to investigate oxidative stress responses of Arabidopsis to low red to far-red ratios of light as a signal of competition using a biological weedy and an artificial source of far-red light. More specifically, elucidation of the signaling role of singlet oxygen in Arabidopsis under low red-to far-red light environments was the major objective of this work. Oxidative stress responses of Arabidopsis to low red (R) to far-red (FR) signals (R:FR ≈ 0.3), generated by a biological weedy and an artificial source of FR light, were compared with a weed-free control (R:FR ≈1.4). In the low R:FR treatments, induction of the shade avoidance responses coincided with increased singlet oxygen (1O2) production and decreased level of superoxide and superoxide dismutase activity. Although the increase of 1O2 was not due to protochlorophyllide accumulation and did not result in cell death, treatments with the 1O2 generator 5-aminolevulinic acid increased sensitivity to cell death. Transcriptome responses minimally resembled those reported in four Arabidopsis 1O2 generating systems such that only few genes (6 out of 1931) were consistently up-regulated supporting the specificity of 1O2 signaling. Moreover, suppressors of jasmonate accumulation, including the 1O2-responsive amidohydrolase ILL6, the sulfotransferase ST2a, which are involved in prioritization of elongation growth versus defense were consistently up-regulated. Our data support a model in which photoreceptors connect low R:FR light cues to the JA signaling pathway. Repression of bioactive JAs via the amidohydrolase ILL6, and sulfotransferase ST2a may promote the shade avoidance (versus defense) and 1O2 acclimation (versus cell death) responses to competition cues.
Project description:Low R:FR signaling through phytochromes induces shade avoidance responses, including petiole elongation. Salicylic acid-mediated defense against pathogens is inhibited under these conditions. Using microarrays we studied the crosstalk between low R:FR and SA at the global gene expression level in Arabidopsis thaliana.
Project description:Low R:FR signaling through phytochromes induces shade avoidance responses, including petiole elongation. Salicylic acid-mediated defense against pathogens is inhibited under these conditions. Using microarrays we studied the crosstalk between low R:FR and SA at the global gene expression level in Arabidopsis thaliana. Plants were exposed for 2 h. to the following treatments: high R/FR with mock spray, low R/FR with mock spray, high R/FR with SA spray, low R/FR with SA spray. Gene expression was determined in petioles.
Project description:Aim of the experiment is the identification of regulatory genes rapidly induced by low R/FR and still up-regulated after prolonged exposure to FR-rich light. To this end, gene expression changes were analysed in Arabidopsis thaliana seedlings after exposure to low R/FR light for a short and a long period of time. The experiment was designed to enable comparison between treated and untreated Arabidopsis seedlings.
Project description:Hypocotyl and cotyledon transcriptome in Arabidopsis thaliana treated with 1 ppm ethylene and shade (low PAR, low blue and low R:FR)