Plants have evolved very sophisticated mechanisms to respond to changes in the environment where they grow. Light is one of the most important environmental inputs since it is the source of energy for plants to produce sugars. In this project we have tested the ability to respond to light of a cell line derived from the model plant Arabidopsis. Whole Arabidopsis seedlings grown in the dark show a very fast response to light, which is characterized by the greening of their organs. We found that the Arabidopsis cell line does become green in response to a shift from dark to light. However, the response is much slower compared to whole seedlings, suggesting that communications between cells and different organs is important for a proper response to light. Also, we have characterized the accumulation and phosphorylation status of the NRPB1 protein upon different light and temperature regimes. This protein is the catalytic subunit of the RNA polymerase II complex, which involved in transcription of messenger RNAs, and therefore plays a key role in the proper expression of genes. While NRPB1 accumulation and phosphorylation seems stable in most growth conditions, we observed an increase in its accumulation upon high temperature, suggesting that a mechanisms operates to promote NRPB1 accumulation, and perhaps activity, under this temperature regime. Last we have performed some immunoprecipitation experiments where NRPB1 protein has been isolated in order to characterize its protein interactors under different growth conditions, with the final goal of answering whether the composition of the RNA polymerase II complex changes in different light and temperature conditions.
During this period of time, we have attended the SEB-INDEPTH meeting in El Escorial, Spain, where we had the chance to discuss the project with experts in the filed.
