This study examines the function of miR160 in potato development and in the hypersensitive response (HR) triggered by potato virus Y (PVY) in cv. Rywal. Modulation of miR160 levels revealed pronounced developmental effects. Depletion of miR160 caused marked alterations in mesophyll tissue organization, including irregular cell shapes and disrupted cell orientation, indicative of impaired anisotropic growth. Strong reduction of miR160 abundance further resulted in the formation of enlarged guard cells. In the context of PVY-Rywal interaction, overexpression of miR160 did not impair R gene–mediated resistance to PVY. Viral spread remained restricted to the vicinity of the HR-associated cell death zone, demonstrating that elevated miR160 levels do not compromise effective immune containment of PVY.