Light sensing in fungi.

Light is essential for life as it provides the energy for the growth of plants and photosynthetic microorganisms. Plants use the energy from light to fix carbon dioxide and produce oxygen, and their photosynthetic apparatus includes sensory systems that optimize light detection. For example, light is a signal that regulates plant growth and promotes the development and orientation of leaves so that they can optimize the capture of the light energy for photosynthesis. Light is also an environmental signal that is used by non-photosynthetic organisms for their orientation, to obtain food and capture prey or to escape from predators, and to anticipate daily or seasonal changes caused by the rotation of the earth. Fungi, for example, do not use light as a source of energy, but rather light is a signal that regulates fungal development and the orientation of the growth of fruiting bodies to optimize the dispersal of spores. In this primer we describe how fungi react to light, the types of photoreceptors that they use to sense light, and the mechanisms of photoreception in a few model fungi. In addition, we will discuss the origin of fungal photoreception, and we will propose future research directions.