TY - JOUR A1 - Schmidt, Romy A1 - Schippers, Jos H. M. A1 - Mieulet, Delphine A1 - Watanabe, Mutsumi A1 - Hoefgen, Rainer A1 - Guiderdoni, Emmanuel A1 - Müller-Röber, Bernd T1 - Salt-Rresponsive ERF1 is a negative regulator of grain filling and gibberellin-mediated seedling establishment in rice JF - Molecular plant N2 - Grain quality is an important agricultural trait that is mainly determined by grain size and composition. Here, we characterize the role of the rice transcription factor (TF) SALT-RESPONSIVE ERF1 (SERF1) during grain development. Through genome-wide expression profiling and chromatin immunoprecipitation, we found that SERF1 directly regulates RICE PROLAMIN-BOX BINDING FACTOR (RPBF), a TF that functions as a positive regulator of grain filling. Loss of SERF1 enhances RPBF expression resulting in larger grains with increased starch content, while SERF1 overexpression represses RPBF resulting in smaller grains. Consistently, during grain filling, starch biosynthesis genes such as GRANULE-BOUND STARCH SYNTHASEI (GBSSI), STARCH SYNTHASEI (SSI), SSIIIa, and ADP-GLUCOSE PYROPHOSPHORYLASE LARGE SUBUNIT2 (AGPL2) are up-regulated in SERF1 knockout grains. Moreover, SERF1 is a direct upstream regulator of GBSSI. In addition, SERF1 negatively regulates germination by controlling RPBF expression, which mediates the gibberellic acid (GA)-induced expression of RICE AMYLASE1A (RAmy1A). Loss of SERF1 results in more rapid seedling establishment, while SERF1 overexpression has the opposite effect. Our study reveals that SERF1 represents a negative regulator of grain filling and seedling establishment by timing the expression of RPBF. KW - RPBF KW - rice KW - grain filling KW - germination KW - SERF1 KW - gibberellic acid Y1 - 2014 U6 - https://doi.org/10.1093/mp/sst131 SN - 1674-2052 SN - 1752-9867 VL - 7 IS - 2 SP - 404 EP - 421 PB - Oxford Univ. Press CY - Oxford ER -