Programmed cell death (PCD) is an umbrella term describing different forms of actively controlled,
genetically encoded cellular suicide. In both plants and animals, PCD has many different functions in
development and health. Yet, in comparison to animals, the knowledge of the molecular
mechanisms that control PCD in plants is still very limited. In the past, we have established the root
cap of the reference plant Arabidopsis thaliana as a novel model system for developmentally
regulated PCD (dPCD) in plants. We have identified a score of transcriptionally regulated dPCDassociated
genes, though most of their individual functions remain enigmatic. Recently, we have
discovered SOMBRERO, LIBITINA1, and LIBITINA2, three transcription factors that act as key
regulators of dPCD, being necessary for regular dPCD execution in the root cap as well as sufficient
to cause ectopic PCD upon inducible misexpression.
Here, we describe a complementary approach of reverse and forward genetics to identify additional
modules of the dPCD regulatory network downstream of SOMBRERO, LIBITINA1, and LIBITINA2, and
upstream of the score of dPCD-associated genes. To this end, we have devised a strategy combining
latest CRISPR technology, protein-DNA interaction assays, and a powerful forward genetics mutant
screen. Adding new modulators to the still sketchy dPCD regulatory network will be crucial for our
understanding of PCD as a fundamental developmental process in plants.