title: BhbZIP60 from Resurrection PlantBoea hygrometricaIs an mRNA Splicing-Activated Endoplasmic Reticulum Stress Regulator Involved in Drought Tolerance.
abstract: Adverse environmental conditions cause endoplasmic reticulum (ER) stress in plants. To mitigate ER stress damage, ER associated transcription factors and inositol-requiring enzyme-1 (IRE1)-mediatedbZIP60mRNA splicing are activated in plants. A drought-induced gene, encoding the ortholog of AtbZIP60, was identified in the resurrection plantBoea hygrometrica, termedBhbZIP60. In response to ER stress and dehydration,BhbZIP60mRNA can be spliced to create a frame shift in the C terminus by the excision of 23b segment in a manner of its ortholog in other plants, thus translocating to the nucleus instead of the cytoplasm. The splicing-activated BhbZIP60 (BhbZIP60S) could function in the same way as itsArabidopsisortholog by restoring the molecular phenotype of the mutantatbzip60. When overexpressed inArabidopsis, BhbZIP60Sprovided transgenic plants with enhanced tolerance to drought, tunicamycin and mannitol stresses with upregulation of the expressions of ER quality control (QC) genes (BiP2, BiP3, CNX1, andsPDI) and abscisic acid (ABA) responsive genes (RD29A, RAB18, andRD17). Furthermore, in the yeast one-hybrid system, BhbZIP60S was capable of interacting with ER stress responsive elements (ERSE and ERSE-II) that exist in the promoters of known ER-QC genes, but not binding to ABA responsivecis-elements (ABREs). Our results demonstrated that drought-induced BhbZIP60 may have a function in drought tolerance via the splicing-activated BhbZIP60S to mediate ER-QC by direct binding to the promoters of ER-QC genes. This study evidently demonstrates the involvement of ER-QC in the drought tolerance ofArabidopsisand the desiccation tolerance of the resurrection plantB. hygrometrica.
authors.affiliation: Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of SciencesBeijing, China; College of Agriculture, Xinjiang Agricultural UniversityUrumqi, China.
authors.forename: Bo
authors.initials: B
authors.lastname: Wang
authors.affiliation: Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of SciencesBeijing, China; College of Life Sciences, University of Chinese Academy of SciencesBeijing, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Du
authors.affiliation: Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences Beijing, China.
authors.forename: Zhennan
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences Beijing, China.
authors.forename: Wenzhong
authors.initials: W
authors.lastname: Xu
authors.affiliation: Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences Beijing, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Deng
keywords: Arabidopsis; Boea hygrometrica; ER-QC; UPR; bZIP60; drought tolerance; mRNA-splicing