The epigenetic chromatin-based regulation of somatic heat stress memory in plants

Abstract In nature, plants are exposed to a multitude of recurring stress events that negatively influence their growth and development, ultimately reduce productivity. Consequently, during the long-term evolutionary process, plants have evolved sophisticated ways to not only acclimate to such events but also “memorize” exposure to previous stress, a process described as priming. Importantly, priming enables plants to survive the otherwise lethal stress event. Although the immediate responses of plants to heat stress have long been studied. The knowledge of priming effects and memory storage mechanisms have only started to get unraveled. The heat stress memory at the somatic level is mediated in part by both the epigenetic and chromatin-based modifications, and both the histone modifications and nucleosome occupancy are associated with it. The present review discusses the recent progress made in understanding heat stress-induced transcriptional memory in plants with a focus on Arabidopsis thaliana.