#700-30 UNDERTAKER transcription factor suppresses corpse clearance during Arabidopsis root cap cell death by interacting with ANAC087.

The Arabidopsis root cap is an unusual plant organ in which the cell number homeostasis is enforced: The generation of new root cap cells in the meristem is balanced with the disposal of aged cells by sloughing and programmed cell death. Cell death execution is followed by a rapid post-mortem corpse clearance that likely controls the amount and nature of cellular material that is released into the rhizosphere. To investigate the genetic regulation of programmed cell death and corpse clearance in Arabidopsis root cap, we used the novel bioinformatic MINI-EX suite. MINI-EX combines the scRNAseq data and information on transcription factor binding motifs to predict transcription factors regulating developmental processes in specific cell types. MINI-EX gene regulatory network analyses suggested a role for several WRKY transcription factors in root cap cell death. A reverse genetics screen revealed a candidate that suppressed root cap corpse clearance when inducibly overexpressed in the root cap. Here, we present a detailed functional analysis of this gene that we dubbed UNDERTAKER (UNT). Interestingly, we found that UNT interacts with ANAC087, a NAC transcription factor that has been previously implicated in the promotion of root cap corpse clearance. Our data suggests that UNT modulates root cap corpse clearance after cell death in concert with ANAC087.