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:Shade avoidance syndrome (SAS) is a strategy of major adaptive significance that includes the elongation of vegetative structures and leaf hyponasty. Major transcriptional rearrangements underlie for the reallocation of resources to elongate vegetative structures and redefine the plant architecture under shade to compete for photosynthesis light. BBX28 is a transcription factor involved in seedling de-etiolation and flowering in Arabidopsis thaliana, but its function in the SAS is completely unknown. Here we studied the function of BBX28 in the regulation of gene expression under simulated shade conditions.
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:This study aims to identify genes which help to understand similar underlying mechanism in the response to shade and wounding in Arabidopsis thaliana plants.
Project description:We analysed global gene expression changes in Arabidopsis thaliana in response to 3h low R:FR or UV-B or both , in order to elucidate the transcriptional reprogramming elicited by UV-B antagonism of shade avoidance response.
Project description:In seedlings, the induction of shade avoidance syndrome (SAS) involves a rapid up-regulation for known shade marker genes and subsequently activates an interacting network of various hormones that will eventually lead to cell elongation. We found that the B-box protein AtBBX24 have positive effects on the SAS (positive regulators). Global expression analysis of col and bbx24 seedlings reveals that a large number of genes involved in hormonal signaling pathways are positively regulated by BBX24 in response to simulated shade.
Project description:Shade avoidance helps plants maximize their access to light for growth under crowding. It is unknown, however, whether a priming shade avoidance mechanism exists that allows plants to respond more effectively to successive shade conditions. Here, we show that the shade-intolerant plant Arabidopsis can remember a first experienced shade event and respond more efficiently to the next event on hypocotyl elongation. The transcriptional regulator PHYTOCHROME-INTERACTING FACTOR 7 (PIF7) and the histone H3K27-demethylase RELATIVE OF EARLY FLOWERING 6 (REF6) were identified as being required for this shade avoidance memory. RNA-sequencing analysis revealed that shade induction of shade memory-related genes was impaired in the pif7 and ref6 mutants. Based on the enrichments of H3K27me3, REF6 and PIF7, we found that priming shade treatment induced PIF7 accumulation, which further recruited REF6 to demethylate H3K27me3 on the chromatin of certain memory-related genes, leading to a state poised for their transcription. Upon the second shade treatment, enhanced shade-mediated induction of these genes resulted in stronger hypocotyl growth responses. We conclude that the transcriptional memory mediated by epigenetic modification plays a key role in the ability of primed plants to remember previously experienced shade and acquire enhanced responses to recurring shade conditions.
