MAPK-triggered chromatin reprogramming by histone deacetylase in plant innate immunity

Microbial-associated molecular patterns (MAMPs) activate several MAP Kinases (MAPKs), which are major regulators of the innate immune response in Arabidopsis that induce large-scale changes in gene expression. Here, we determined whether MAMP-triggered gene expression involves chromatin modifications at the chromosomal level. Our results show that histone acetylation and deacetylation are major regulators of MAMP-triggered gene expression and implicate the histone deacetylase HD2B in the reprogramming of defense gene expression and innate immunity. The MAPK MPK3 directly interacts with and phosphorylates HD2B, thereby regulating the intra-nuclear compartmentalization and function of the histone deacetylase. By studying a number of gene loci that undergo MAMP-dependent activation or repression, our data reveal a mechanistic model for how protein kinase signaling directly impacts chromatin reprogramming in plant defense.