The Transcriptional Regulation of Acclimation to High Light in Arabidopsis thaliana

Plants undergo the process of HL acclimation in response to new higher light conditions. Over 5 to 9 days of higher light exposure, plants enhance their photosynthetic capacity to take advantage of the new environment. HL acclimation is mediated through light-responsive photoreceptors such as CRY1, which drive changes in transcription. Transcriptional regulators are crucial in bringing about cellular alterations required for HL acclimation through changing the expression of genes. A previous study created a network of HL acclimation transcription factors centred around the transcriptional regulator BBX32 and the transcription factor HY5. BBX32 and HY5 Arabidopsis thaliana mutants were experimentally shown to have perturbed HL acclimation phenotypes. I aimed to investigate HL acclimation through further testing of the HL TF network and analysis of transcriptional data. Arabidopsis thaliana mutants of HL TF network genes were experimentally tested for HL acclimation perturbations. Analysis was conducted on an RNA-seq data set of BBX32 over-expressor and hy5-2 mutants exposed to a HL treatment. Novel HL acclimation genes have been experimentally validated by using mutants of genes from the HL TF network. A BBX32 allelic series of mutants created utilising a CRISPR/CAS9 gene editing system has provided further evidence of the role of BBX32 within HL acclimation. New links have been discovered between phytohormone signalling, systemic acquired resistance and HL acclimation. Together these results give further insight into HL acclimation and its potential uses for improving plant productivity.