Identification of CpbZIP11 in Cyclocarya paliurus Involved in Environmental Stress Responses

Abstract

Environmental stresses can disrupt protein structure, resulting in unfolded or misfolded proteins, thereby triggering endoplasmic reticulum (ER) stress. The unfolded protein response (UPR), particularly as activated by Arabidopsis AtbZIP60 gene, is pivotal for counteracting ER stress and ensuring cell survival. The medicinal plant, Cyclocarya paliurus, known for its wealth of beneficial compounds, is threatened by environmental stresses, limiting the exploration of its therapeutic potential. In order to better exploit and utilize its value, it is necessary to understand the signal pathway of environmental stresses. Here, we identify a homolog of AtbZIP60 in C. paliurus, termed CpbZIP11, which can be upregulated by tunicamycin. The conserved double stem-loop structure in its mRNA is spliced under environmental stresses. This splicing event results in a novel CpbZIP11 mRNA variant, leading to the production of a nuclear-localized CpbZIP11 protein with transcriptional activation activity in yeast. We further delve into the study of evolutionary lineage and motif conservation of CpbZIP11 homologs across various plant groups. This research illuminates the stress adaptation mechanisms in C. paliurus and deepens our understanding of the bZIP evolution, which endows versatility for the understanding of this transcription factor.