ABSTRACT
Living organisms are confronted with rapid environmental changes in the course of their development, such as changes in light, temperature, humidity, and nutrient supply. The sensing of these environmental changes is a vital capacity. An important environmental cue is light which is perceived by photoreceptors. Following perception, an internal signal is generated which is subsequently transported via a signal transduction chain and finally causes the observed response and the acclimatization of the organisms to environmental light conditions. The signal transduction chains usually comprise protein components (e.g, protein kinases, protein phosphatases, and G-proteins) and secondmessenger molecules (e.g., Ca2+ and cyclic AMP). In higher plants light is essential for photosynthesis whereas in fungi normal growth and development are possible in the complete absence of light. Nevertheless, light is also an important signal for fungi and affects many aspects of fungal development and physiology.
