Unfolded protein response (UPR) mediated under heat stress in plants

Drastic fluctuation in temperature during crop growth challenges its yield to a greater extent, thus diminishing the agricultural productivity globally. At the cellular level, protein homeostasis is altered or disturbed directly or indirectly by the high temperature. Improper protein folding due to heat stress creates ER stress in the endoplasmic reticulum (ER). In order to balance the protein folding demand and its capacity and to maintain ER homeostasis, cells activate unfolded protein response (UPR), as a homeostatic mechanism. The transcription factors, bZip60 and bZip28/17 have been reported as the key modules of UPR for alleviating ER stress. Despite UPR mechanisms has been extensively investigated, the intervention of heat stress with ER homeostasis remains unclear. This review summarizes the key findings on this potential nexus. Additionally, the link between ER associated degradation and plant growth regulators during heat stress were also addressed.