Leaf senescence is controlled by a complex regulatory network in which robustness is ensured by the activity of transcription factors and epigenetic regulators. However, how these coordinate the process of leaf senescence remains poorly understood. We found that WHIRLY1 interacts with Histone Deacetylase (HDA)15, a Reduced Potassium Dependence3 (RPD3)/HDA1-type HDA, by using green fluorescent protein-nanotrap-mass spectrum assays. The development-dependent interaction between WHIRLY1 and HDA15 was further confirmed by bimolecular fluorescence complementation assays and co-immunoprecipitation assays in Arabidopsis. Multi-omics genome-wide transcriptome and H3K9 acetylome enrichment analysis showed that HDA15 delays leaf senescence and flowering by repressing the expression of the positive regulators of leaf senescence and flowering, such as LOX2 and LARP1C, and reducing H3K9ac levels at these loci; WHIRLY1 and HDA15 co-target to the region near the transcription start site of a subset of nutrient recycling-related genes (e.g., Glutathione S-transferases 10, non-coding RNA, and photosystem II protein D1 synthesizer attenuator PDIL1-2), as well as WRKY53 and ELF4, and co-repress their expression by removing H3K9 acetylation. Our study revealed a key transcription regulatory node of nutrient recycling and senescence-associated genes involved in leaf senescence and flowering via the recruitment of HDA15 by the single-stranded DNA/RNA-binding protein WHIRLY1.

中文翻译：

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WHIRLY1 募集组蛋白去乙酰化酶 HDA15 抑制拟南芥叶片衰老和开花

叶片衰老由一个复杂的调控网络控制，其中转录因子和表观遗传调控因子的活性确保了其稳健性。然而，这些如何协调叶片衰老过程仍然知之甚少。我们发现 WHIRLY1 与组蛋白脱乙酰酶 (HDA)15 相互作用，这是一种减少钾依赖性 3 (RPD3)/HDA1 型 HDA，通过使用绿色荧光蛋白-纳米阱质谱分析。拟南芥中的双分子荧光互补测定和免疫共沉淀测定进一步证实了 WHIRLY1 和 HDA15 之间的发育依赖性相互作用. 多组学全基因组转录组和H3K9乙酰组富集分析表明，HDA15通过抑制叶片衰老和开花的正调节因子LOX2和LARP1C的表达，降低这些基因座的H3K9ac水平，从而延缓叶片衰老和开花；WHIRLY1 和 HDA15 共同靶向营养循环相关基因子集（例如，谷胱甘肽 S-转移酶 10、非编码 RNA 和光系统 II 蛋白 D1 合成衰减子 PDIL1-2）的转录起始位点附近的区域，如以及WRKY53和ELF4，并通过去除 H3K9 乙酰化来共同抑制它们的表达。我们的研究揭示了通过单链 DNA/RNA 结合蛋白 WHIRLY1 募集 HDA15参与叶片衰老和开花的营养循环和衰老相关基因的关键转录调控节点。