Eukaryotic organisms have quality control mechanisms that allow misfolded or unassembled proteins to be retained in the endoplasmic reticulum (ER) and subsequently degraded by ER-associated degradation (ERAD).The ERAD pathway is well-studied in yeast and mammals; however, the biological functions of plant ERAD have not been reported.Through molecular and cellular biological approaches, we determined ERAD is necessary for plants to overcome salt stress.Upon salt treatment, ubiquitinated proteins increased in plant cells, especially unfolded proteins which quickly accumulated in the ER and subsequently induced ER stress responses.Defective HRD3A in HRD1/HRD3 complex, one complex of the ERAD mechanism, resulted in alteration of the unfolded protein response (UPR), increased plant sensitivity to salt, and retention of ERAD substrates in plant cells.Furthermore, we demonstrated that Ca2+ release from the ER is involved in the elevation of UPR and reactive oxygen species (ROS) in the ERAD-related plant salt response pathway.