Working model for AtNUDT7 protein, linking redox and oxidative cell death cycles. Biotic and abiotic stresses including suboptimal growing conditions lead to alterations in ascorbate, GSH and PNs. Changes in NADH induces AtNUDT7 and maybe crucial to restore the balance of NAD+:NADH redox couple. In the absence of AtNUDT7 protein, NADH levels increase and trigger the accumulation of SA by an unknown mechanism and activate the SAR pathway, which in turn can antagonize ABA signaling. SA accumulation can trigger cell death via ROS, which in turn can inhibit the cell death promotive SA signal. Reduction in ATP levels in Atnudt7-1 may be due to constitutive activation of defense/stress signaling that in turn may lead to growth retardation.