Lowland rice responds to partial to complete submergence by one of two strategies. The escape and quiescence strategies are controlled by distinctions in the ethylene responsive factors encoded by the SUB1 locus. Quiescence requires strong induction of SUB1A by ethylene, which is increased as a consequence of submergence and biosynthesis. SUB1A is either poorly induced or absent in lowland rice varieties that attempt to escape submergence. The presence or absence of SUB1A does not affect the decline in ABA observed in response to submergence. In tolerant varieties, ethylene-promoted induction of SUB1A results in limited responsiveness to bioactive gibberellin (GA) because of increases in the GA response repressors SLR1 and SLRL1. The SUB1C gene, always present at the SUB1 locus, is triggered by de-repression of GA responsiveness. The underwater escape promoted by GA includes increased starch and soluble sugar catabolism and increased cell wall expansin proteins that promote expansibility (adapted from Fukao and Bailey-Serres 2008).