Updated project metadata. Soil salinity is a major environmental constraint affecting crop growth and threatening global food security. Plants adapt to salinity by optimizing performance of stomata, the microscopic sphincters inserted into the wax-covered epidermis of the shoot, which balance CO2 intake for photosynthetic carbon gain and concomitant water loss. Stomata are formed by two guard cells (GCs) that are morphologically and functionally distinct from the other leaf cells. In order to better understand the molecular mechanisms underlying stomatal function under saline conditions we used proteomics approach to study isolated GCs from the salt-tolerant sugar beet species.