21 p.-4 fig.-2 tab. 1 graph. abst.The interplay between the phytohormone abscisic acid (ABA) and the gasotransmitter nitric oxide (NO) regulates seed germination and post-germinative seedling growth. We show that GAP1 (germination in ABA and cPTIO 1) encodes the transcription factor ANAC089 with a critical membrane-bound domain and extranuclear localization. ANAC089 mutants lacking the membrane-tethered domain display insensitivity to ABA,salt, and osmotic and cold stresses, revealing a repressor function. Whole-genome transcriptional profiling and DNA-binding specificity reveals that ANAC089 regulates ABA- and redox-related genes. ANAC089 truncated mutants exhibit higher NO and lower ROS and ABA endogenous levels, alongside an altered thiol and disulfide homeostasis. Consistently, translocation of ANAC089 to the nucleus is directed by changes in cellular redox status after treatments with NO scavengers and redox-related compounds. Our results reveal ANAC089 to be a master regulator modulating redox homeostasis and NO levels, able to repress ABA synthesis and signaling during Arabidopsis seed germination and abiotic stress.Wethank the Spanish networks BIO2015-68957-REDT and RED2018-102397-T for stimulating discussions, as well as Dr. José M. Carrasco and Dr. Pablo Vera (IBMCP-CSIC) for help with the protein-expression experiments of the PBM. This work was financed by grants EcoSeed Impacts of Environmental Conditions on Seed Quality ‘‘EcoSeed-311840’’ ERC.KBBE.2012.1.1-01;BIO2017-85758-R and CSD2007-00057 (TRANSPLANTA) from the Ministerio de Ciencia, Innovación y Universidades (MICIU) (Spain); SA313P18 and SA137P20 from Junta de Castilla y León; Escalera de Excelencia CLU-2018-04 co-funded by the P.O. FEDER of Castilla y León 2014–2020 Spain (to O.L.); and the PhD and University Teacher Training Fellowship, Spanish Ministry of Science and Education (to P.A.).Peer reviewe
