Regulating PCD in plant cells: Intracellular acidification plays a pivotal role together with calcium signaling.

Programmed cell death (PCD) occurs in different tissues in response to a number of different signals in plant cells. Drawing from work in several different contexts, including root cap cell differentiation, plant response to biotic and abiotic stress, and some self-incompatibility (SI) systems, the data suggest that, despite differences, there are underlying commonalities in early decision-making stages of PCD. Here, we focus on how two cellular events, increased [Ca2+]cyt levels and cytosolic acidification, appear to act as early signals involved in regulating both developmental- and stimulus-induced PCD in plant cells.