# A Promoter Collection for Cell‐Targeted Analysis Within the Stomatal Complex

## TL;DR

This paper introduces new genetic tools to study the roles of guard cells and surrounding epidermal cells in stomatal function.

## Contribution

The study provides tissue-specific promoters for targeted gene expression in guard and epidermal cells of Arabidopsis, Brassica, and barley.

## Key findings

- Promoters enable precise gene expression in guard cells and adjacent epidermal cells.
- These tools improve physiological analysis of stomatal mechanics and solute-water flux.
- The promoters are applicable to model species like Arabidopsis, Brassica, and barley.

## Abstract

Stomatal aperture is driven by changes in turgor of the guard cells that surround the stomatal pore. Epidermal cells immediately surrounding the guard cells are thought to contribute to the kinetics of aperture changes through changes in their turgor that opposes the guard cells and thought their putative roles in solute storage for use by the guard cells. Nonetheless, our knowledge remains fragmentary of surrounding cell mechanics, in large part because the tools and strategies needed to target the surrounding cells independent of the guard cells are limited. Here, we have analyzed sets of promoters for Arabidopsis, Brassica, and barley that will allow physiological studies of the roles of epidermal cells and also surrounding cells in the case of barley in stomatal behavior. These tissue‐specific promoters offer distinct advantages over widely used, constitutive promoters by enabling precise and targeted gene expression within guard cells and the adjacent epidermal cells. As genetic tools, the promoters will have applications in strategies centered on physiological analyses and differential comparisons following expression targeted between the guard cells and the foliar epidermis as a whole. As such, they are well suited to questions around the mechanics of solute and water flux that will advance an understanding of the stomatal complex in these model species.