Department of Biochemistry, Institute of Plant Biology, School of Life Sciences, State Key Laboratory of Genetic Engineering, Collaborative Innovation Center for Genetics and Development, Fudan University, Shanghai 200438, China.
Institut de Biologie Moléculaire des Plantes, CNRS, Université de Strasbourg, Strasbourg Cedex 67084, France.
Plant Cell. 2022 Mar 4;34(3):1100-1116. doi: 10.1093/plcell/koab318.
Chromatin remodelers act in an ATP-dependent manner to modulate chromatin structure and thus genome function. Here, we report that the Arabidopsis (Arabidopsis thaliana) remodeler CHROMATIN REMODELING19 (CHR19) is enriched in gene body regions, and its depletion causes massive changes in nucleosome position and occupancy in the genome. Consistent with these changes, an in vitro assay verified that CHR19 can utilize ATP to slide nucleosomes. A variety of inducible genes, including several important genes in the salicylic acid (SA) and jasmonic acid (JA) pathways, were transcriptionally upregulated in the chr19 mutant under normal growth conditions, indicative of a role of CHR19 in transcriptional repression. In addition, the chr19 mutation triggered higher susceptibility to the JA pathway-defended necrotrophic fungal pathogen Botrytis cinerea, but did not affect the growth of the SA pathway-defended hemibiotrophic bacterial pathogen Pseudomonas syringae pv. tomato DC3000. Expression of CHR19 was tissue-specific and inhibited specifically by SA treatment. Such inhibition significantly decreased the local chromatin enrichment of CHR19 at the associated SA pathway genes, which resulted in their full activation upon SA treatment. Overall, our findings clarify CHR19 to be a novel regulator acting at the chromatin level to impact the transcription of genes underlying plant resistance to different pathogens.
染色质重塑因子以依赖于 ATP 的方式发挥作用，以调节染色质结构，从而影响基因组功能。在这里，我们报告称，拟南芥（Arabidopsis thaliana）重塑因子 CHROMATIN REMODELING19（CHR19）在基因体区域富集，其缺失会导致基因组中核小体位置和占有率的大量变化。与这些变化一致，体外实验验证了 CHR19 可以利用 ATP 来滑动核小体。各种诱导型基因，包括水杨酸（salicylic acid，SA）和茉莉酸（jasmonic acid，JA）途径中的几个重要基因，在正常生长条件下，chr19 突变体中的转录被上调，表明 CHR19 在转录抑制中起作用。此外，chr19 突变导致对 JA 途径防御的坏死真菌病原体 Botrytis cinerea 的敏感性更高，但不影响 SA 途径防御的半活体细菌病原体 Pseudomonas syringae pv. tomato DC3000 的生长。CHR19 的表达具有组织特异性，并被 SA 处理特异性抑制。这种抑制显著降低了与 SA 途径相关基因的 CHR19 在局部染色质上的富集，从而导致它们在 SA 处理后完全激活。总的来说，我们的研究结果阐明了 CHR19 作为一种新型的染色质水平调节因子，影响了植物对不同病原体抗性的相关基因的转录。
