The presence of H3K4me3 histone mark is positively correlated with expression at the DAM loci in sweet cherry during dormancy

In perennial species such as sweet cherry, dormancyis a period of repressed growth that acts to protect sensitive tissues during unfavourable climatic conditions. Dormancyand budburst are strongly affected by temperature. The mean surface temperature of the earth is increasing and this climatic change may have negative consequences on the dormancyrelease and result in lower cherry production. Despite this well-described effect of temperature on phenology, the molecular events regulating dormancyare still poorly understood. It has been shown that the expression of DORMANCY-ASSOCIATED MADS-box(DAM)-related genes is up-regulated in dormant budsand inversely down-regulated in non-dormant budsin several perennial plantspecies (peach, pear, leafyspurge, apple). Recent studies suggested the role of epigenetic mechanisms, such as DNA methylation and chromatin modifications, in the regulation of bud dormancyand dormancyrelease. To better understand the mechanisms underlying the effect of temperature on dormancywe assessed genome-wide dynamics of one chromatin mark ( H3K4me3) associated with open chromatin and gene activation. It was coupled with expression analysis during dormancyin floral budsof sweet cherry cultivar 'Burlat' ( Prunusavium L.). We detected transcriptional and histone methylationdynamics of dormancy-related genes (PavDAM5 and PavDAM6) during the dormancycycle.