Programmed cell death in plant development

Programmed cell death (PCD) is a genetically-enabled process in which select cells organize their own destruction. PCD is ubiquitous in all eukaryotic kingdoms and is employed by both unicellular and multicellular organisms as part of normal development or in response to external stimuli. In plants, PCD is necessary for growth and survival and can either be developmentally regulated or environmentally induced. A unique example of developmental PCD is perforation (holes) formation in lace plant leaves. These holes are situated equidistantly between longitudinal and transverse veins, giving leaves a lattice-like pattern. During perforation formation, discrete subpopulations of cells undergo PCD while adjacent cells remain intact. I have characterized the cell death process during perforation formation in lace plant and showed that this aquatic plant is an ideal model system to study developmental PCD. Lace plant is native to Madagascar and difficult to grow in aquarium conditions. I have successfully developed an axenically cultured lace plant system to work on developmental PCD. We still do not know what cues trigger PCD at the appropriate stage of leaf development, the signaling pathways, and the molecular mechanisms. Therefore, my overall aim is to identify factors inducing perforations and the mechanisms that regulate the PCD in lace plant using biochemical and microscopical techniques with four approaches: 1) To investigate changes in the actin cytoskeleton during lace plant PCD; 2) To compare induced and developmental PCD in the same plant species; 3) To develop both a stable and transient transformation protocol for lace plant; 4) To test the effect of calcium inhibitors on cell death in plants. These results will help us to determine whether there are common mechanisms between animal and plant PCD or whether they evolved independently.