Overexpression of AcNIP5;1, a Novel Nodulin-Like Intrinsic Protein from Halophyte Atriplex canescens, Enhances Sensitivity to Salinity and Improves Drought Tolerance in Arabidopsis

Abstract

Aquaporins (AQPs) in plants have been shown to facilitate the transport of water and other small molecules through biological membranes. This activity is essential for plant stress management during drought. Here, we describe and characterize a novel aquaporin gene AcNIP5;1 (Atriplex canescens nodulin 26-like intrinsic protein 5;1) isolated from an A. canescens cDNA library. qRT-PCR results indicated that the transcript level in leaf tissue of AcNIP5;1 was upregulated by 20 % PEG 6000 and downregulated by 400 mM NaCl. To further understand the function of AcNIP5;1, we generated transgenic Arabidopsis thaliana plants that expressed AcNIP5;1 under control of the CaMV35S promoter. The overexpression of AcNIP5;1 in these transgenic Arabidopsis plants resulted in higher drought tolerance and sensitivity to salinity compared to wild-type plants on both MS plate and pot experiments. AcNIP5;1 protein tagged with GFP was localized to the cell plasma membrane in Nicotiana benthamiana. Our results suggest that AcNIP5;1 might play a role in drought tolerance in A. canescens.