Transcription profiling of Arabidopsis acclimation to light intensity

The acclimation of plants to environmental factors (light/temperature/nutrient availability) plays a crucial role in determining their tolerance to stress their ability to compete with other plants and the efficiency with which external inputs are used for growth and productivity. Some of the clearest responses involve the major modifications in the composition of the photosynthetic apparatus in response to light intensity. Photosynthetic acclimation. The acclimation response involves changes in the abundance of a large number of proteins in different cell compartments occurring at different intensity thresholds. The signal transduction chain is complex and involves crosstalk between redox control and other pathways that control photosynthetic gene expression but is poorly understood. Over the past 7 years we have laid the foundations for a molecular genetic approach by characterising the responses of Arabidopsis thaliana to growth in and transfer between high and low light conditions(1-6). Arabidopsis exhibits all the key features of photosynthetic acclimation: changes in maximum photosynthetic rate in leaf structure and in the levels of light-harvesting complexes photosystems and enzymes of carbon metabolism. Method: Samples A-1, A-2 and A-3 were grown at a light intensity of 400 umol.m-2.s-1 until rosette growth was complete. Plants for samples A-2 and A-3 were then transferred to 100 umol.m-2.s-1. Samples A-4, A-5 and A-6 were grown at 100umol.m-2.s-1 until rosette growth was complete, when plants for samples A-5 and A-6 were transferred to 400 umol.m-2.s-1. Samples were taken 24 hours after transfer to the different light intensity and samples A-3 and A-6 were taken 72 hours after transfer. Keywords: Photosynthesis Number of plants pooled: