Received: 5 January 2018 | Accepted: 21 March 2018 DOI: 10.1002/jcb.26882 RESEARCH ARTICLE bZIP17 regulates the expression of genes related to seed storage and germination, reducing seed susceptibility to osmotic stress Nicolás Cifuentes-Esquivel 1 | Jonathan Celiz-Balboa 1 | Carlos Henriquez-Valencia 1 | Irina Mitina 1 | Paulina Arraño-Salinas 1 | Adrián A. Moreno 1,2 | Claudio Meneses 1,2 | Francisca Blanco-Herrera 1,3 | Ariel Orellana 1,2 1 Centro de Biotecnología Vegetal, Facultad de Ciencias Biológicas, Universidad Andres Bello, Santiago, Chile 2 FONDAP Center for Genome Regulation, Centro de Biotecnología Vegetal, Universidad Andres Bello, Santiago, Chile 3 Millennium Institute for Integrative Systems and Synthetic Biology (MIISSB), Santiago, Chile Correspondence Ariel Orellana and Francisca Blanco- Herrera, Centro de Biotecnología Vegetal, Facultad de Ciencias Biológicas, Universidad Andrés Bello, Avenida República 217, Santiago, RM 8370146, Chile. Email: aorellana@unab.cl (AO); mblanco@unab.cl (FBH) Funding information Programa Atracción e Inserción de Capital Humano Avanzado, Grant number: PAI 821320026; Fondo de Financiamiento de Centros de Investigación en Áreas Prioritarias, Grant numbers: FONDAP CRG 15090007, PB-16; Fondo Nacional de Desarrollo Científico y Tecnológico, Grant number: Fondecyt 1170259 Abstract Low temperatures, salinity, and drought cause significant crop losses. These conditions involve osmotic stress, triggering transcriptional remodeling, and consequently, the restitution of cellular homeostasis and growth recovery. Protein transcription factors regulate target genes, thereby mediating plant responses to stress. bZIP17 is a transcription factor involved in cellular responses to salinity and the unfolded protein response. Because salinity can also produce osmotic stress, the role of bZIP17 in response to osmotic stress was assessed. Mannitol treatments induced the transcript accumulation and protein processing of bZIP17. Transcriptomic analyses showed that several genes associated with seed storage and germination showed lower expression in bzip17 mutants than in wild-type plants. Interestingly, bZIP17 transcript was more abundant in seeds, and germination analyses revealed that wild-type plants germinated later than bzip17 mutants in the presence of mannitol, but no effects were observed when the seeds were exposed to ABA. Finally, the transcript levels of bZIP17 target genes that control seed storage and germination were assessed in seeds exposed to mannitol treatments, which showed lower expression levels in bzip17 mutants compared to the wild-type seeds. These results suggest that bZIP17 plays a role in osmotic stress, acting as a negative regulator of germination through the regulation of genes involved in seed storage and germination. KEYWORDS Arabidopsis thaliana, bZIP17, osmotic stress, salt stress, seed germination 1 | INTRODUCTION Plants, as sessile organisms, are exposed to a wide range of environmental stresses and severe climate changes. Although gradual evolution has granted plants a remarkable ability to adapt to hostile environments, several stressful conditions, such as freezing, salinity, and drought, remain responsible for over 50% of losses in agriculturally important crops. 1–4 Although freezing, salinity, and drought activate specific plant responses, all these factors induce changes in cell osmotic potential, leading to water and cell turgor loss, among Nicolás Cifuentes-Esquivel and Jonathan Celiz-Balboa contributed equally to this work. J Cell Biochem. 2018;1–12. wileyonlinelibrary.com/journal/jcb © 2018 Wiley Periodicals, Inc. | 1