Epigenetic regulation and ROS signaling in plant stress adaptation: an integrated framework.

Plants respond to environmental stress by integrating epigenetic regulation with reactive oxygen species (ROS) signaling. This review examines the bidirectional interactions between epigenetic mechanisms and ROS homeostasis in plant stress adaptation, with a particular emphasis on drought resistance. Four epigenetic mechanisms, including histone modifications, DNA methylation, chromatin remodeling, and non-coding RNAs, control the expression of ROS-related genes, while in turn, ROS also alter chromatin structure and DNA methylation patterns. We propose that these interactions take the form of dynamic regulatory networks rather than one-way pathways, where changes in DNA methyltransferases and demethylation factors via ROS create reversible epigenetic states. This bilateral regulation can establish self-strengthening circuits that are capable of providing immediate responses to recurring stress. However, there is still a significant lack of knowledge, including the inconsistent reproducibility of stress priming protocols in studies, the incomplete understanding of how global oxidative stress induces epigenetic changes at specific sites, and the limited capacity for transgenerational transmission of stress-induced modifications. We review the evidence for epigenetic memory in plant stress responses, distinguish recurring adaptive plasticity from random variation, and highlight key mechanistic research directions for developing seasonally resilient crops through targeted epigenetic strategies.