Cryptochrome-mediated light responses in plants.

Cryptochromes (CRYs) are photolyase-like flavoproteins that have been found in all evolutionary lineages. Plant and animal CRYs are no longer DNA-repairing enzymes but they apparently gained other biochemical functions in evolution. Plant CRYs are UV-A/blue-light photoreceptors and play a pivotal role in plant growth and development, whereas animal CRYs act as either photoreceptors or transcription regulators. The first CRY gene was isolated from Arabidopsis thaliana, which regulates stem growth, flowering time, stomatal opening, circadian clock, and other light responses. CRYs are also found in all major crops investigated, with additional functions discovered, such as seed germination, leaf senescence, and stress responses. In this chapter, we will review some aspects of CRY-mediated light responses in plants. Readers are referred to other review articles for photochemistry and signal transduction mechanism of plant CRYs (Liu et al., 2010, 2011; Fankhauser and Ulm, 2011) [1-3].