Understanding the Mechanisms of Plant Stress Response, Priming, and Memory

Can plants “remember” past events in the absence of a structure that functions similarly to the central nervous system of animals?  The examination of stress responses to abiotic factors has been a long-term focus of plant research (Pecinka et al. 2012).  With the predicted rise in average temperatures and longer periods of extreme weather, studying plant responses to abiotic stresses will be helpful in understanding plant ecology and evolution. Pre-exposure to stress may alter plants’ subsequent responses, implying that plants exercise a form of “stress memory” (Ding et al. 2012).  Such memory could be life-long and may even be transferred to the following generation (Boyko et al., 2010; Pecinka et al., 2009).  Due to the long-term effects of this stress memory, it is hypothesized to be conferred by epigenetic mechanisms (Sani et al., 2013; Smith and Workman, 2012).  There have been few studies that investigated a plant’s ability to remember a stress throughout its lifecycle (Bruce et al., 2007; Sani et al., 2013; Ding et al., 2012; Kim et al., 2012).  Research on stress resistance and stress memory is limited to Arabidopsis.  We developed a system that could be used to test the response of maize seedlings to drought, cold, and salinity stresses.  Two-week old maize seedlings were subjected to low level stresses, allowed to recover, and stressed again.  We will present whole genome RNA expression suggesting that plants “remember” stress and discuss the possible mechanisms for this memory.