Salt stress poses a serious threat to crop yield and future food production, thus researches on the mechanism of plant tolerance to salinity will give a theoretical foundation for improving plants at to give better production under salt stress.

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, Dr. Qi XIE’s group found that ERAD is necessary for plants to overcome salt stress. Upon salt treatment ubiquitinated proteins increased in plant cells, especially unfolded proteins that quickly accumulated in the ER and subsequently induced ER stress responses. Defect in HRD3A of the HRD1/HRD3 complex of the ERAD pathway resulted in alteration of the unfolded protein response (UPR), increased plant sensitivity to salt, and retention of ERAD substrates in plant cells. Furthermore, they demonstrated that Ca2+ release from the ER is involved in the elevation of UPR and reactive oxygen species (ROS) participates the ERAD-related plant salt response pathway.

HRD3 is the first component in plant ERAD degradation pathway reported. This discovery is the breakthrough of ERAD in plant filed which will promote the study of mechanism of ERAD in plant hormone and stress signaling. The paper was published on Cell Research online on December 28, 2010. The Ph.D student Lijing Liu in Dr. Xie’s lab is the first author of this work.

AUTHOR CONTACT:

XIE Qi, Ph.D.

Institute of Genetics and Developmetnal Biology, Chinese Academy of Sciences, Beijing, China.

E-mail: qxie@genetics.ac.cn

Proposed model for the rold of ERAD in the salt signaling pathway in plants. UP: unfolded protein.