Interaction between cold and high light stresses distinguishes transcriptional responses for freezing tolerance and photoprotection in <i>Arabidopsis thaliana</i>

In natural environments, plants are exposed to several abiotic stresses. Although plant responses to individual stressors have been well characterized, our knowledge of their responses to combined stressors is limited. In this study, we have analyzed the transcriptional responses of Arabidopsis to a combination of high light and cold stresses, because these conditions are considered major stressors that impact the same target, photosynthesis. Transcriptome analysis revealed that cold-activated genes can be divided into the following two groups: (1) genes whose expression is enhanced by high light and (2) genes whose expression is not enhanced by high light. The first group includes photoprotection-related genes, such as <i>ELIP2</i> and <i>CHS</i>, and the second group includes <i>DREB1A</i>/<i>CBF3</i>-activated frost tolerance genes, which are associated with their physiological roles. Our findings help to elucidate the molecular machinery involved in plant acclimation during the winter season.