Abstract
In plants, there are three major classes of immune receptors. The largest class encodes intracellular NB-LRR type R proteins. The two other classes of immune receptors are transmembrane receptor-like kinases (RLKs) and receptor-like proteins (RLPs). Unlike RLKs, RLPs do not have an intracellular kinase domain. We have obtained a series of mutants such as snc2-1D, bir1-1 and mkk1 mkk2 that constitutively activate resistance responses mediated by different classes of immune receptors. snc2-1D contains a gain-of-function mutation in a RLP. bir1-1 activates cell death and immunity mediated by the RLK SOBIR1, whereas mkk1 mkk2 displayed phenotypes similar as bir1-1. We have performed suppressor screens in these mutant backgrounds to identify new regulatory components of plant defense. Recent progress on studies of the suppressor mutants of snc2-1D, bir1-1 and mkk1 mkk2 will be presented.
