Open AccessActivation of a plant nucleotide binding‐leucine rich repeat disease resistance protein by a modified self protein
Author(s) -
DeYoung Brody J.,
Qi Dong,
Kim SangHee,
Burke Thomas P.,
Innes Roger W.
Publication year - 2012
Publication title -
cellular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.542
H-Index - 138
eISSN - 1462-5822
pISSN - 1462-5814
DOI - 10.1111/j.1462-5822.2012.01779.x
Subject(s) - biology , nicotiana benthamiana , effector , arabidopsis , leucine rich repeat , pseudomonas syringae , tobacco etch virus , biochemistry , protein kinase a , microbiology and biotechnology , green fluorescent protein , kinase , virology , plant virus , gene , mutant , virus , potyvirus
Summary Nucleotide binding‐leucine rich repeat (NB‐LRR) proteins function as intracellular receptors for the detection of pathogens in both plants and animals. Despite their central role in innate immunity, the molecular mechanisms that govern NB‐LRR activation are poorly understood. The Arabidopsis NB‐LRR protein RPS5 detects the presence of the Pseudomonas syringae effector protein AvrPphB by monitoring the status of the Arabidopsis protein kinase PBS1. AvrPphB is a cysteine protease that targets PBS1 for cleavage at a single site within the activation loop of PBS1. Using a transient expression system in the plant Nicotiana benthamiana and stable transgenic Arabidopsis plants we found that both PBS1 cleavage products are required to activate RPS5 and can do so in the absence of AvrPphB. We also found, however, that the requirement for cleavage of PBS1 could be bypassed simply by inserting five amino acids at the PBS1 cleavage site, which is located at the apex of the activation loop of PBS1. Activation of RPS5 did not require PBS1 kinase function, and thus RPS5 appears to sense a subtle conformational change in PBS1, rather than cleavage. This finding suggests that NB‐LRR proteins may function as fine‐tuned sensors of alterations in the structures of effector targets.