Scientists found that by overexpressing a sugar-sensing enzyme, called hexokinase, in field-grown tobacco plants, they could improve intrinsic water-use efficiency (iWUE) without decreasing photosynthetic rates or biomass production.Scientists found that by overexpressing a sugar-sensing enzyme, called hexokinase, in field-grown tobacco plants, they could improve intrinsic water-use efficiency (iWUE) without decreasing photosynthetic rates or biomass production.