"Suppressors of the Arabidopsis lsd5 cell death mutation identify genes involved in regulating disease resistance responses."
Genetics 151, 305-319.
Morel, J-B and JL Dangl
Summary
"Cell death is associated with the development of the plant disease resistance hypersensitive reaction
(HR). Arabidopsis lsd mutants that spontaneously exhibit cell death reminiscent of the HR were identified
previously. To study further the regulatory context in which cell death acts during disease resistance, one
of these mutants, lsd5, was used to isolate new mutations that suppress its cell death phenotype. Using a
simple lethal screen, nine lsd5 cell death suppressors, designated phx (for the mythological bird Phoenix
that rises from its ashes), were isolated. These mutants were characterized with respect to their response
to a bacterial pathogen and oomycete parasite. The strongest suppressors—phx2, 3, 6, and 11-1—showed
complex, differential patterns of disease resistance modifications. These suppressors attenuated disease
resistance to avirulent isolates of the biotrophic Peronospora parasitica pathogen, but only phx2 and phx3
altered disease resistance to avirulent strains of Pseudomonas syringae pv tomato. Therefore, some of these
phx mutants define common regulators of cell death and disease resistance. In addition, phx2 and phx3
exhibited enhanced disease susceptibility to different virulent pathogens, confirming probable links between
the disease resistance and susceptibility pathways."