Saussurea involucrata PIP2;7 improves photosynthesis and drought resistance by decreasing the stomatal density and increasing intracellular osmotic pressure

Aquaporin proteins are very important for water transport across the plasma membrane. In this study, the plasma membrane intrinsic protein PIP2;7 cloned from Saussurea involucrata was overexpressed in Arabidopsis thaliana. Transgenic lines showed rapid growth, with increased leaf numbers and leaf sizes, due to high rates of photosynthesis, transpiration, and stomatal conductance. Moreover, SiPIP2;7 conferred drought resistance in Arabidopsis by improving water use efficiency and intracellular osmotic pressure via a decrease in the stomatal density and increases in intracellular Cl−. These phenotypes were attributed to the effects of SiPIP2;7 on the relative expression levels of target genes related to the stomatal development and ion transport. Moreover, SiPIP2;7 gene improve drought resistance and fruit yield of tomato. These results indicated that the SiPIP2;7 gene is effective for breeding new varieties with high drought resistance and yield.