The researchers implanted a special gene that triggers the hormone production, in the tobacco's chloroplasts.
Chloroplasts are the small compartments in leaf cells that generate energy from sunlight.
While earlier experiments with tobacco plants had resulted in very small hormone yields, involving the chloroplasts increased the hormone production by 300 times. These earlier experiments had embedded transplanted genes in the plants' cell nuclei. Thus, an uncontrolled transmission of the genetic manipulation to other plants can be ruled out.