Short-Term Epigenetic Responses of Pinus brutia to Fire Stress: Insights from a Prescribed Burning in Greece

<b>Background/Objectives</b>: Fire is a dominant ecological force in Mediterranean ecosystems, shaping the adaptive traits of forest species such as <i>Pinus brutia</i>. Prescribed burning (also called controlled burning) is the intentional, carefully planned use of fire under specific environmental conditions to manage vegetation and reduce wildfire risk. While morphological and physiological fire adaptations are well-documented, emerging evidence highlights the role of epigenetic mechanisms-such as DNA methylation and histone modifications-in mediating stress responses. <b>Methods</b>: This study investigates genome-wide epigenetic changes in <i>P. brutia</i> following a prescribed burning experiment on Chios Island, Greece. Using methylation-sensitive amplified polymorphism (MSAP) analysis, we compared temporal shifts on epigenetic profiles before and after fire exposure extracting DNA from the same trees. <b>Results</b>: A significant increase in polymorphic epiloci, epigenetic diversity indices, and private epigenetic bands after prescribed burning was revealed, suggesting a stress-induced reprogramming of the epigenome. Concurrent measurements of midday needle water potential indicated an exploratory association between water stress and epigenetic shifts. Furthermore, Fireline Intensity (FI) correlated with epigenetic diversity index signaling an immediate response of the tree. <b>Conclusions</b>: These findings support the hypothesis that fire stress induces epigenetic responses in <i>P. brutia</i>, potentially enhancing resilience to future environmental challenges. Further research is required to address the level of heritability of these epigenetic changes in next generation and connect these indexes with adaptation and sustainability of forest ecosystems.