DNA methylation regulates fruit ripening in tomato, and disruption of the DNA demethylase DEMETER-LIKE 2 (DML2) results in genome-wide DNA hypermethylation and impaired ripening. We report here that the transcription factors Ripening Inhibitor (RIN) and FRUITFULL 1 (FUL1) play critical roles in mediating the effect of DNA methylation on tomato fruit ripening. RIN and FUL1 are silenced in dml2 mutant plants, and the defective ripening phenotype of dml2 is mimicked by the rin/ful1 double mutant. Restoration of RIN expression in dml2 partially rescues its ripening defects. DNA methylation controls ripening not only by regulating the expression of RIN and FUL1 but also by interfering with the genomic binding of RIN. In dml2 mutant plants, RIN cannot bind to some of its targets in vivo even though DNA methylation does not interfere with RIN binding in vitro; this inhibited binding in vivo is correlated with increased DNA methylation and histone H3 enrichment within 100 bp of the binding site. Our work uncovers the molecular mechanisms underlying DNA methylation control of fruit ripening in tomato.

中文翻译：

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两种转录因子在介导番茄果实成熟的表观遗传调控中起关键作用


DNA 甲基化调节番茄果实的成熟，DNA 去甲基化酶 DEMETER-LIKE 2 （DML2） 的破坏导致全基因组 DNA 高甲基化和成熟受损。我们在这里报道了转录因子成熟抑制剂 （RIN） 和 FRUITFULL 1 （FUL1） 在介导 DNA 甲基化对番茄果实成熟的影响中起关键作用。RIN 和 FUL1 在 dml2 突变体植物中沉默，并且 RIN/FUL1 双突变体模拟 dml2 的缺陷成熟表型。在 dml2 中恢复 RIN 表达部分挽救了其成熟缺陷。DNA 甲基化不仅通过调节 RIN 和 FUL1 的表达来控制成熟，还通过干扰 RIN 的基因组结合来控制成熟。在 dml2 突变植物中，即使 DNA 甲基化不干扰体外 RIN 结合，RIN 也不能在体内与其某些靶标结合;这种体内抑制的结合与结合位点 100 bp 内 DNA 甲基化和组蛋白 H3 富集的增加相关。我们的工作揭示了番茄果实成熟的 DNA 甲基化控制的潜在分子机制。