Evidence for in vivo interactions between dehydrins and the aquaporin AtPIP2B.

Plants have developed mechanisms that allow them to tolerate different abiotic stresses. Among these mechanisms, the accumulation of specific proteins such as dehydrins (DHNs) and aquaporins (AQPs) can protect other proteins from damage during dehydration and may allow the control of water loss, respectively. Although both types of proteins are involved in plant protection against dehydration stress, a direct interaction between them has not been explored. A previous screen to identify potential OpsDHN1 protein interactions revealed an aquaporin as a possible candidate. Here, we used the Bimolecular Fluorescence Complementation (BiFC) approach to investigate the direct interaction of the cactus OpsDHN1 protein with the Arabidopsis plasma membrane PIP family aquaporin AtPIP2B (At2G37170). Since AtPIP2B is a membrane protein and OpsDHN1 is a cytosolic protein that may be peripherally associated with membranes, we propose that OpsDHN1/AtPIP2B interaction takes place at cellular membranes. Furthermore, we also demonstrate the interaction of AtPIP2B with the three Arabidopsis dehydrins COR47 (AT1G20440), ERD10 (At1g20450), and RAB18 (At5g66400).