大量证据表明表观遗传调控在植物逆境响应与记忆中发挥重要作用，但已有证据主要基于对少数位点的解析。近年组学研究表明PRC2介导的H3K27me3修饰在渗透胁迫后变化非常广泛，且其恢复缓慢的特性很可能参与了胁迫记忆。但胁迫处理数据噪声大，对表观修饰的影响大多是动态而又定量的，而相关比较工具匮乏制约了胁迫响应表观机制的深入解析，导致胁迫处理后H3K27me3变化影响的靶基因及特异性参与响应的PRC2组分都还不清楚。申请人结合实验和定量比较模型，通过多组学数据整合初步定义了可信度较高的渗透胁迫响应和记忆基因，并发现胁迫响应激素ABA诱导的H3K27me3下调与渗透胁迫响应及记忆基因的上调表达密切相关，而且PRC2核心组分参与调控ABA介导的凋亡反应。本项目拟在此基础上全面刻画H3K27me3在渗透胁迫响应中的动态变化，并结合遗传生理和高通量实验深入解析PRC2调控拟南芥渗透胁迫响应与记忆的具体机制

Accumulating evidence revealed the importance of epigenetic machineries in regulating plant stress responses and memory. However, majority of available researches focused on limited number of loci. Recent genome-wide study revealed that Polycomb Repress Complex 2 (PRC2) mediated H3K27me3 is one major epigenomic modification showing wide-spread changes following osmotic stress, and importantly, the slow restoration of this modification made it as a potential candidate for regulating plant osmotic stress memory. However, the genomic data obtained following stress treatment suffered from big noise, and the change of epigenome is generally dynamic and quantitative, which pose big challenges for data integration and quantitative comparison. Thus, the dynamic changes of H3K27me3 after osmotic treatment and their effect on the expression of target genes, the specific PRC2 components involved in osmotic stress response, as well as the underlying mechanisms are still not well understood. In our preliminary works, based on high-throughput experiments and our model for quantitative comparison of ChIP-seq data, we defined a high confidence set of stress response and memory related genes, and observed the close relationship between ABA induced H3K27me3 reduction surrounding genes involved in osmotic stress response and memory. Based on these findings, this project aims to systematically characterize the dynamic changes of H3K27me3 upon osmotic stresses, and further dissect the underlying mechanism how PRC2 components regulate osmotic stress response and memory in Arabidopsis through an integrative analysis of genetic, physiological, and high-throughput data.