title: A Developmental Switch of Gene Expression in the Barley Seed Mediated by HvVP1 (Viviparous-1) and HvGAMYB Interactions.
abstract: The accumulation of storage compounds in the starchy endosperm of developing cereal seeds is highly regulated at the transcriptional level. These compounds, mainly starch and proteins, are hydrolyzed upon germination to allow seedling growth. The transcription factor HvGAMYB is a master activator both in the maturation phase of seed development and upon germination, acting in combination with other transcription factors. However, the precise mechanism controlling the switch from maturation to germination programs remains unclear. We report here the identification and molecular characterization of Hordeum vulgare VIVIPAROUS1 (HvVP1), orthologous to ABA-INSENSITIVE3 from Arabidopsis thaliana HvVP1 transcripts accumulate in the endosperm and the embryo of developing seeds at early stages and in the embryo and aleurone of germinating seeds up to 24 h of imbibition. In transient expression assays, HvVP1 controls the activation of Hor2 and Amy6.4 promoters exerted by HvGAMYB. HvVP1 interacts with HvGAMYB in Saccharomyces cerevisiae and in the plant nuclei, hindering its interaction with other transcription factors involved in seed gene expression programs, like BPBF. Similarly, this interaction leads to a decrease in the DNA binding of HvGAMYB and the Barley Prolamine-Box binding Factor (BPBF) to their target sequences. Our results indicate that the HvVP1 expression pattern controls the full Hor2 expression activated by GAMYB and BPBF in the developing endosperm and the Amy6.4 activation in postgerminative reserve mobilization mediated by GAMYB. All these data demonstrate the participation of HvVP1 in antagonistic gene expression programs and support its central role as a gene expression switch during seed maturation and germination.
authors: Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid-Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, and Escuela Técnica Superior de Ingenieros Agrónomos, Campus de Montegancedo, Universidad Politécnica de Madrid, Pozuelo de Alarcón, 28223 Madrid, Spain.
authors: Zamira
authors: Z
authors: Abraham
authors: Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid-Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, and Escuela Técnica Superior de Ingenieros Agrónomos, Campus de Montegancedo, Universidad Politécnica de Madrid, Pozuelo de Alarcón, 28223 Madrid, Spain.
authors: Raquel
authors: R
authors: Iglesias-Fernández
authors: Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid-Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, and Escuela Técnica Superior de Ingenieros Agrónomos, Campus de Montegancedo, Universidad Politécnica de Madrid, Pozuelo de Alarcón, 28223 Madrid, Spain.
authors: Manuel
authors: 0000-0002-7826-5872
authors: M
authors: Martínez
authors: Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid-Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, and Escuela Técnica Superior de Ingenieros Agrónomos, Campus de Montegancedo, Universidad Politécnica de Madrid, Pozuelo de Alarcón, 28223 Madrid, Spain.
authors: Ignacio
authors: 0000-0003-4773-7176
authors: I
authors: Rubio-Somoza
authors: Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid-Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, and Escuela Técnica Superior de Ingenieros Agrónomos, Campus de Montegancedo, Universidad Politécnica de Madrid, Pozuelo de Alarcón, 28223 Madrid, Spain.
authors: Isabel
authors: 0000-0001-9865-902X
authors: I
authors: Díaz
authors: Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid-Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, and Escuela Técnica Superior de Ingenieros Agrónomos, Campus de Montegancedo, Universidad Politécnica de Madrid, Pozuelo de Alarcón, 28223 Madrid, Spain.
authors: Pilar
authors: P
authors: Carbonero
authors: Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid-Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, and Escuela Técnica Superior de Ingenieros Agrónomos, Campus de Montegancedo, Universidad Politécnica de Madrid, Pozuelo de Alarcón, 28223 Madrid, Spain jesus.vicente@upm.es.
authors: Jesús
authors: 0000-0002-6332-1712
authors: J
authors: Vicente-Carbajosa
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D002467:Cell Nucleus / Q000378:metabolism; D024202:Electrophoretic Mobility Shift Assay; D056625:Endosperm / Q000235:genetics; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D018525:Germination / Q000235:genetics; D001467:Hordeum / Q000235:genetics* / Q000254:growth & development*; D008954:Models, Biological; D009928:Organ Specificity / Q000235:genetics; D010802:Phylogeny; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D012326:RNA Splicing / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012639:Seeds / Q000235:genetics*; D015533:Transcriptional Activation / Q000235:genetics; D020798:Two-Hybrid System Techniques
chemical_list: D010940:Plant Proteins; D012333:RNA, Messenger