show Abstracthide AbstractGrafting has been used as a method to increase stress tolerance in Solanaceae plants. However, little is known about how grafting affects gene expression and epigenetic modification of shoot apical meristems (SAMs) that lead to stress tolerance. Here, we studied the effects of self and different-varieties rootstock grafting on tomato gene expression, histone H3 modifications, H3K4me3 and H3K27me3, cytosine-5 DNA methylation, and drought stress tolerance.