Abstract
Most organisms have developed various strategy to react rapidly to temperature downshift and regulate expression of many genes to acclimate to low temperature. However, information about how low-temperature signal is perceived and transduced is limited. In photosynthetic organisms, such as plants and cyanobacteria, temperature downshift in the light results in an imbalance between the light energy absorbed through photochemistry and the energy utilized through metabolism. Thus, temperature downshift in the light is not only decrease of temperature but also increase of photosystem II excitation pressure, which reflects the relative reduction state of the photosystem. We carried out microarray analyses of responses to low temperature both in the light and in the dark to separate low-temperature effects from effects of excitation pressure. We identified 15 ORFs upregulated by temperature downshift both in the light and in the dark.
