title: ABA signalling is fine-tuned by antagonistic HAB1 variants.
abstract: Group A protein type 2C phosphatases (PP2Cs) are negative regulators of abscisic acid (ABA) signalling and plant adaptation to stress. However, our knowledge of the regulation of PP2C activity is limited. Here we report that the PP2C HAB1 undergoes alternative splicing to produce two splice variants, which encode HAB1.1 and HAB1.2, that play opposing roles in ABA-mediated seed germination and ABA-mediated post-germination developmental arrest. HAB1.2 is predominately formed in the presence of ABA and prevents seed germination and post-germinative growth. HAB1.2 interacts with OST1, but cannot inhibit OST1 kinase activity; thus, it functions as a positive regulator of ABA signalling. We also identified an RNA-recognition motif-containing protein, RBM25, as a potential regulator of HAB1 alternative splicing and molecular diversity. Our results reveal a mechanism for turning ABA signalling on and off and for plant adaptation to abiotic stress.
authors.affiliation: The State Key Laboratory of Plant Cell and Chromosome Engineering, Center for Agricultural Research Resources, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, 286 Huaizhong Road, Shijiazhuang, Hebei 050021, China.
authors.forename: Zhijuan
authors.initials: Z
authors.lastname: Wang
authors.affiliation: The State Key Laboratory of Plant Cell and Chromosome Engineering, Center for Agricultural Research Resources, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, 286 Huaizhong Road, Shijiazhuang, Hebei 050021, China.|State Key Laboratory of Agricultural Microbiology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
authors.forename: Hongtao
authors.initials: H
authors.lastname: Ji
authors.affiliation: The State Key Laboratory of Plant Cell and Chromosome Engineering, Center for Agricultural Research Resources, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, 286 Huaizhong Road, Shijiazhuang, Hebei 050021, China.|Graduate University of Chinese Academy of Sciences, No. 19A Yuquan Road, Beijing 100049, China.
authors.forename: Bingjian
authors.initials: B
authors.lastname: Yuan
authors.affiliation: The State Key Laboratory of Plant Cell and Chromosome Engineering, Center for Agricultural Research Resources, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, 286 Huaizhong Road, Shijiazhuang, Hebei 050021, China.
authors.forename: Shuangfeng
authors.initials: S
authors.lastname: Wang
authors.affiliation: The State Key Laboratory of Plant Cell and Chromosome Engineering, Center for Agricultural Research Resources, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, 286 Huaizhong Road, Shijiazhuang, Hebei 050021, China.|Graduate University of Chinese Academy of Sciences, No. 19A Yuquan Road, Beijing 100049, China.
authors.forename: Chao
authors.initials: C
authors.lastname: Su
authors.affiliation: The State Key Laboratory of Plant Cell and Chromosome Engineering, Center for Agricultural Research Resources, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, 286 Huaizhong Road, Shijiazhuang, Hebei 050021, China.
authors.forename: Bin
authors.initials: B
authors.lastname: Yao
authors.affiliation: The State Key Laboratory of Plant Cell and Chromosome Engineering, Center for Agricultural Research Resources, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, 286 Huaizhong Road, Shijiazhuang, Hebei 050021, China.
authors.forename: Hongtao
authors.initials: H
authors.lastname: Zhao
authors.affiliation: The State Key Laboratory of Plant Cell and Chromosome Engineering, Center for Agricultural Research Resources, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, 286 Huaizhong Road, Shijiazhuang, Hebei 050021, China.|State Key Laboratory of Agricultural Microbiology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
authors.forename: Xia
authors.initials: X
authors.lastname: Li
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism*; D020816:Amino Acid Motifs; D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D014644:Genetic Variation; D018525:Germination; D007527:Isoenzymes / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D010749:Phosphoprotein Phosphatases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism; D012639:Seeds / Q000201:enzymology / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D015398:Signal Transduction
chemical_list: D029681:Arabidopsis Proteins; D007527:Isoenzymes; D000040:Abscisic Acid; D011494:Protein Kinases; C472139:OST1 protein, Arabidopsis; C514757:HAB1 protein, Arabidopsis; D010749:Phosphoprotein Phosphatases