Exposure to UV radiation does not always yield a negative effect for photosynthetic organisms, however. Recently there has been a paradigm shift in understanding UV as a regulatory signal rather than solely a stressor, as UV perception is involved in critical metabolic functions (Rozema et al., 1997; Davey et al., 2012; Hideg et al., 2013; Morales et al., 2013; Singh et al., 2014; Williamson et al., 2014; Neugart and Schreiner, 2018). Researchers have begun to instead classify UV radiation as a “eustress,” (Hideg et al., 2013). In this framework, UV-B is understood to stimulate a state of alert that includes activation defenses, especially if the radiation is experienced in small doses. For example, UVR8, the UV-B receptor in plants, mediates the accumulation of transcripts encoding early light-inducible proteins (ELIPs) (Singhet al., 2014), which function in photoprotection (Hutin et al., 2003). Furthermore, low doses of UV radiation can induce protective responses that increase a plant’s tolerance to other abiotic and biotic stressors (Frohnmeyer and Staiger, 2003). For instance, ELIPs are also important for desiccation tolerance in resurrection plants (Zeng, 2002; Oliver et al., 2004; Van Buren et al., 2019).