A team of Japanese researchers has identified a gene in the mustard plant Arabidopsis that controls the movement of light-gathering cells in leaves. The discovery could lead to the construction of artificially enhanced plants, they say.

Chloroplasts are microscopic bodies in plant cells that convert light energy into a form that the plant can use.

Takatoshi Kagawa, from the Japan Science and Technology Corporation in Saitama Prefecture, and colleagues at academic institutes in Japan, identified a gene called NPL1 that regulates the movement of chloroplasts according to light conditions.

Plant leaves work like living solar panels: In weak sunlight the chloroplasts spread themselves over the face of the cell to maximize light capture, but when sunlight is strong, they retreat to the relative "shade" of the cell wall.

Plants use blue light to orient their leaves and maximize light interception, and to move their chloroplasts to the best place in the cell. The researchers examined plants that were defective in the chloroplast movement response and found they carried a mutant form of the NPL1 gene. Their results were published Thursday in the journal Science.

"If we can control chloroplast positioning in a cell using this gene, it might be possible to perform photosynthesis much more efficiently, under strong light conditions," said Masamitsu Wada, of Tokyo Metropolitan University, who was on the research team.

"In this case, we would be using artificial plants and artificially regulated light conditions."

Chloroplasts move away from strong light, so the researchers were able to form the kanji "hikari" (light) on a mustard plant leaf by shining light on it covered by a template of the Chinese character. The area in the light changed from dark green to light green in about 1.5 hours.