Open AccessThe TIR Domain of TIR-NB-LRR Resistance Proteins Is a Signaling Domain Involved in Cell Death Induction
Author(s) -
Michał Swiderski,
Doris Birker,
Jonathan D. G. Jones
Publication year - 2009
Publication title -
molecular plant-microbe interactions
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.565
H-Index - 153
eISSN - 1943-7706
pISSN - 0894-0282
DOI - 10.1094/mpmi-22-2-0157
Subject(s) - programmed cell death , biology , nicotiana benthamiana , microbiology and biotechnology , signal transduction , death domain , arabidopsis , genetics , mutant , gene , apoptosis
In plants, the TIR (toll interleukin 1 receptor) domain is found almost exclusively in nucleotide-binding (NB) leucine-rich repeat resistance proteins and their truncated homologs, and has been proposed to play a signaling role during resistance responses mediated by TIR containing R proteins. Transient expression in Nicotiana benthamiana leaves of “TIR + 80”, the RPS4 truncation without the NB-ARC domain, leads to EDS1-, SGT1-, and HSP90-dependent cell death. Transgenic Arabidopsis plants expressing the RPS4 TIR+80 from either dexamethasone or estradiol-inducible promoters display inducer-dependent cell death. Cell death is also elicited by transient expression of similarly truncated constructs from two other R proteins, RPP1A and At4g19530, but is not elicited by similar constructs representing RPP2A and RPP2B proteins. Site-directed mutagenesis of the RPS4 TIR domain identified many loss-of-function mutations but also revealed several gain-of function substitutions. Lack of cell death induction by the E160A substitution suggests that amino acids outside of the TIR domain contribute to cell death signaling in addition to the TIR domain itself. This is consistent with previous observations that the TIR domain itself is insufficient to induce cell death upon transient expression.