Sodium butyrate applied to Petunia hybrida seeds under a long-day photoperiod has a negative impact (reduced seedling length, decreased production of photosynthetic pigments, and accumulation of DNA damage) on early seedling development, whereas its administration under dark/light conditions (complete dark conditions for 5 days followed by exposure to long-day photoperiod for 5 days) bypasses some of the adverse effects. Genotoxic stress impairs plant development. To circumvent DNA damage, plants activate DNA repair pathways in concert with chromatin dynamics. These are essential during seed germination and seedling establishment, and may be influenced by photoperiod variations. To assess this interplay, an experimental design was developed in Petunia hybrida, a relevant horticultural crop and model species. Seeds were treated with different doses of sodium butyrate (NaB, 1 mM and 5 mM) as a stress agent applied under different light/dark conditions throughout a time period of 10 days. Phenotypic (germination percentage and speed, seedling length, and photosynthetic pigments) and molecular (DNA damage and gene expression profiles) analyses were performed to monitor the response to the imposed conditions. Seed germination was not affected by the treatments. Seedling development was hampered by increasing NaB concentrations applied under a long-day photoperiod (L) as reflected by the decreased seedling length accompanied by increased DNA damage. When seedlings were grown under dark conditions for 5 days and then exposed to long-day photoperiod for the remaining 5 days (D/L), the damaging effects of NaB were circumvented. NaB exposure under L conditions resulted in enhanced expression of HAT/HDAC (HISTONE ACETYLTRANSFERASES/HISTONE DEACTEYLASES) genes along with repression of genes involved in DNA repair. Differently, under D/L conditions, the expression of DNA repair genes was increased by NaB treatment and this was associated with lower levels of DNA damage. The observed DNA damage and gene expression profiles suggest the involvement of chromatin modification- and DNA repair-associated pathways in response to NaB and dark/light exposure during seedling development.

中文翻译：

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丁酸钠通过光周期变化诱导基因毒性应激，并差异调节矮牵牛幼苗染色质修饰和 DNA 修复相关基因的表达

在长日照条件下将丁酸钠施用于矮牵牛种子对幼苗早期发育有负面影响（减少幼苗长度、减少光合色素的产生和 DNA 损伤的积累），而在黑暗/光照条件下施用丁酸钠（完全黑暗条件下 5 天，然后暴露于长日照周期 5 天）绕过了一些不利影响。基因毒性应激损害植物发育。为了规避 DNA 损伤，植物与染色质动力学一起激活 DNA 修复途径。这些在种子萌发和幼苗建立期间是必不可少的，并且可能受光周期变化的影响。为了评估这种相互作用，在Petunia hybrida（一种相关的园艺作物和模式物种）中开发了一种实验设计。种子用不同剂量的丁酸钠（NaB、1 mM 和 5 mM）作为胁迫剂在不同光照/黑暗条件下在 10 天的时间段内施用。进行表型（发芽百分比和速度、幼苗长度和光合色素）和分子（DNA 损伤和基因表达谱）分析以监测对施加条件的反应。种子萌发不受处理的影响。幼苗发育受到在长日光周期 (L) 下增加 NaB 浓度的阻碍，这反映在幼苗长度减少伴随 DNA 损伤增加。当幼苗在黑暗条件下生长 5 天，然后在剩余的 5 天（D/L）暴露于长日光周期，避免了 NaB 的破坏作用。L 条件下的 NaB 暴露导致 HAT/HDAC（组蛋白乙酰转移酶/组蛋白脱乙酰酶）基因的表达增强，同时抑制了参与 DNA 修复的基因。不同的是，在 D/L 条件下，NaB 处理增加了 DNA 修复基因的表达，这与较低水平的 DNA 损伤有关。观察到的 DNA 损伤和基因表达谱表明染色质修饰和 DNA 修复相关途径参与响应 NaB 和幼苗发育过程中的暗/光暴露。NaB 处理增加了 DNA 修复基因的表达，这与较低水平的 DNA 损伤有关。观察到的 DNA 损伤和基因表达谱表明染色质修饰和 DNA 修复相关途径参与响应 NaB 和幼苗发育过程中的暗/光暴露。NaB 处理增加了 DNA 修复基因的表达，这与较低水平的 DNA 损伤有关。观察到的 DNA 损伤和基因表达谱表明染色质修饰和 DNA 修复相关途径参与响应 NaB 和幼苗发育过程中的暗/光暴露。