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. Genome-wide correlation of H3K9ac modification and HD2B binding profile  to transcription.

微生物相关分子模式（Microbial-associated molecular patterns, MAMPs）可激活多种丝裂原活化蛋白激酶（Mitogen-activated protein kinases, MAPKs），而MAPKs是拟南芥先天免疫反应的核心调控因子，能够诱导大规模基因表达改变。本研究旨在明确MAMP触发的基因表达是否涉及染色体水平的染色质修饰。研究结果显示，组蛋白乙酰化与去乙酰化是MAMP触发的基因表达的主要调控机制，并证实组蛋白去乙酰化酶HD2B（histone deacetylase HD2B）参与防御基因表达重编程与先天免疫调控。丝裂原活化蛋白激酶MPK3（MAPK MPK3）可直接与HD2B相互作用并使其发生磷酸化，进而调控该组蛋白去乙酰化酶的核内区室化分布与功能。通过对一系列受MAMP依赖性激活或抑制的基因位点进行研究，本研究的数据揭示了一套机制模型，阐明蛋白激酶信号通路如何直接影响植物防御过程中的染色质重编程。本研究还对全基因组范围内H3K9乙酰化修饰（H3K9ac modification）与HD2B结合谱同转录过程的相关性进行了分析。