Phototropin-related NPL1 controls chloroplast relocation induced by blue light

In photosynthetic cells, chloroplasts migrate towards illuminated sites to optimize photosynthesis and move away from excessively illuminated areas to protect the photosynthetic machinery(1). Although this movement of chlorop lasts in response to light has been known for over a century, the photorece ptor mediating this process has not been identified. The Arabidopsis gene N PL1 (ref. 2) is a paralogue of the NPH1 gene, which encodes phototropin, a photoreceptor for phototropic bending(3). Here we show that NPL1 is require d for chloroplast relocation induced by blue light. A loss-of-function npl1 mutant showed no chloroplast avoidance response in strong blue light, wher eas the accumulation of chloroplasts in weak light was normal. These result s indicate that NPL1 may function as a photoreceptor mediating chloroplast relocation.