International Team of Scientists Reveals How Plants Turn Light Switch On and Off

An international team of researchers led by scientists at the RIKEN Center for Sustainable Resource Science in Japan, Fujian Agriculture and Forestry University in China, and the University of California, Los Angeles have uncovered the mechanisms through which a key photoreceptor (Cryptochrome 2) that allows plants to respond to blue light is switched on and off, allowing plants to remain responsive to light.

The research team screened transgenic lines of Arabidopsis to find lines that expressed phenotypes similar to a mutant strain that does not respond properly to blue light. They identified lines that overexpress a protein, called BIC1, which corresponds to the mutant phenotype. This protein blocks Cryptochrome 2 photoreceptor. They also found that Cryptochrome 2 takes a dimer form when exposed to blue light, and this homodimer form is the active form. In the presence of the BIC1 protein, the dimer form disappeared.

The researchers said, "We have shown that there is a desensitization mechanism, where the photoactivated photoreceptor is regulated in blue light to avoid excess response. This is important as it allows plants to maintain the homeostasis of their blue light responsiveness in order to adapt to the fluctuating light environment in nature."

For more, read the article at the RIKEN website.