David W. Ow
South China Botanical Garden

During dire conditions, the channelling of resources into reproduction ensures species preservation.  This strategy of survival through the next generation is particularly important for plants that are unable to escape their environment but can produce hardy seeds.  Here we describe the multiple roles of OXIDATIVE STRESS 2 (OXS2) in maintaining vegetative growth, activating stress tolerance, or entering into stress-induced reproduction. In the absence of stress, OXS2 is cytoplasmic and is needed for vegetative growth; in its absence, the plant flowers earlier. Upon stress, OXS2 is nuclear and is needed for stress tolerance; in its absence, the plant is stress sensitive. OXS2 can activate its own gene and those of floral integrator genes, with direct binding to the floral integrator promoter SOC1. Stress-induced SOC1 expression and stress-induced flowering are impaired in mutants with defects in OXS2 and three of the four OXS2-like paralogs. The autoactivation of OXS2 may be a commensurate response to the stress intensity, stepping up from a strategy based on tolerating the effects of stress to one of escaping the stress via reproduction.