SHORTROOT-mediated increase in stomatal density has no impact on photosynthetic efficiency

SHORTROOT (SRT) is a transcription factor that contributes to developmental patterning non-cell autonomously, by moving between cells. In leaves, SRT has been shown to contribute to sub-epidermal patterning specified by distance from the vein. Schuler et al. explored whether it also contributes to epidermal patterning, specifically stomatal patterning, in rice leaves. They found that after altering the expression domain of SRT to include bundle-sheath cells surrounding the vein, stomatal patterning was affected. Interestingly, although the plants ectopically expressing SRT produced additional stomata, there was no measurable increase in their photosynthetic efficiency. (Summary by Mary Williams)  Plant Physiol.  10.1104/pp.17.01005