State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Jiangsu 210095, China.
Plant Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, NY, 14853, USA.
Plant Cell Physiol. 2017 Dec 1;58(12):2202-2216. doi: 10.1093/pcp/pcx155.
ATP-dependent chromatin-remodeling factors use the energy of ATP hydrolysis to alter the structure of chromatin and are important regulators of eukaryotic gene expression. One such factor encoded by CHR5 (Chromatin-Remodeling Factor 5) in Arabidopsis (Arabidopsis thaliana) was previously found to be involved in regulation of growth and development. Here we show that CHR5 is required for the up-regulation of the intracellular immune receptor gene SNC1 (SUPPRESSOR OF npr1-1, CONSTITUTIVE1) and consequently the autoimmunity induced by SNC1 up-regulation. CHR5 functions antagonistically with another chromatin-remodeling gene DDM1 (DECREASED DNA METHYLATION 1) and independently with a histone mono-ubiquitinase HUB1 (HISTONE MONOUBIQUITINATION 1) in SNC1 regulation. In addition, CHR5 is a positive regulator of SNC1-independent plant immunity against the bacterial pathogen Pseudomonas syringae. Furthermore, the chr5 mutant has increased nucleosome occupancy in the promoter region relative to the gene body region at the whole-genome level, suggesting a global role for CHR5 in remodeling nucleosome occupancy. Our study thus establishes CHR5 as a positive regulator of plant immune responses including the expression of SNC1 and reveals a role for CHR5 in nucleosome occupancy which probably impacts gene expression genome wide.
ATP 依赖的染色质重塑因子利用 ATP 水解的能量来改变染色质的结构，是真核生物基因表达的重要调节剂。拟南芥（Arabidopsis thaliana）中 CHR5（染色质重塑因子 5）编码的一种这样的因子先前被发现参与生长和发育的调节。在这里，我们表明 CHR5 是细胞内免疫受体基因 SNC1（SUPPRESSOR OF npr1-1，CONSTITUTIVE1）上调所必需的，因此 SNC1 上调诱导的自身免疫。CHR5 与另一个染色质重塑基因 DDM1（DECREASED DNA METHYLATION 1）和 HUB1（HISTONE MONOUBIQUITINATION 1）的功能拮抗，在 SNC1 调节中独立发挥作用。此外，CHR5 是 SNC1 非依赖性植物对细菌病原体丁香假单胞菌的免疫的正调节剂。此外，与野生型相比，chr5 突变体在整个基因组水平上在启动子区域的核小体占有率相对于基因体区域增加，这表明 CHR5 在重塑核小体占有率方面具有全局作用。因此，我们的研究确立了 CHR5 作为植物免疫反应的正调节剂，包括 SNC1 的表达，并揭示了 CHR5 在核小体占有率中的作用，这可能会影响整个基因组的基因表达。
