The earliest events following R gene engagement are ion fluxes at the plasma membrane and the generation of superoxide and nitric oxide. Calcium influx and phosphorylation cascades have also been implicated as defense responses. All of these events lead to a massive transcriptional re-programming and, in many cases, to a very rapid cell death at the site of attempted infection. It is not clear whether this HR cell death is causal to stopping the pathogen by depriving it of nutrients, or whether it is a consequence of a plant cell based response that also kills the pathogen. We isolated a set of mutants that mis-regulate an HR-like cell death and we focus now on the LSD1 gene family. This is probably a scaffold protein for various transcription factors, that may also be a transcription factor itself.
This work is funded by NIH and NSF.