Cruciferous sprout is a new form of vegetable product rich in bioactive compounds, especially glucosinolates. Previous studies have focused on increasing the accumulation of glucosinolates in cruciferous sprouts by applying different chemical regulators, with a particular focus on their contribution to nutritional quality and health benefits. Nevertheless, the effects of melatonin and UV-B irradiation on glucosinolate biosynthesis remain unclear. In this study, it was found that changes in melatonin concentrations significantly affected the contents of individual as well as total aliphatic and indolic glucosinolates. The 5 μmol · L melatonin was decided as the optimum concentration that could increase the content of beneficial glucosinolates including glucoraphanin and 4-methoxy glucobrassicin in Chinese kale sprouts. Notably, the enhancement of glucosinolate accumulation by melatonin treatment could be further amplified by UV-B irradiation. Furthermore, our results showed that R2R3-MYB transcription factor BoaMYB28 and BoaMYB51, which are central regulators of aliphatic and indolic glucosinolate biosynthesis respectively, were both involved in the regulation of glucosinolate biosynthesis by melatonin and UV-B irradiation. Additionally, the expression of glucosinolate biosynthetic genes, including , , , , , , and participated in the formation of core structures and , , , and involved in the side-chain modification of aliphatic and indolic glucosinolate, was regulated by melatonin or UV-B irradiation. Taken together, these findings provide a potential strategy for improving the nutritional quality and resistance of Chinese kale sprouts.

中文翻译：

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UV-B 照射增强羽衣甘蓝芽中褪黑素诱导的有益芥子油苷的积累


十字花科芽菜是一种新型蔬菜产品，富含生物活性化合物，尤其是芥子油苷。先前的研究重点是通过应用不同的化学调节剂来增加十字花科豆芽中芥子油苷的积累，特别关注它们对营养质量和健康益处的贡献。然而，褪黑激素和 UV-B 照射对芥子油苷生物合成的影响仍不清楚。在这项研究中，发现褪黑激素浓度的变化显着影响个体以及总脂肪族和吲哚硫代葡萄糖苷的含量。确定5 μmol·L褪黑素为提高羽衣甘蓝芽菜中有益芥子油苷含量的最佳浓度，包括萝卜硫苷和4-甲氧基芥子油苷。值得注意的是，褪黑素处理对硫代葡萄糖苷积累的增强作用可以通过 UV-B 照射进一步放大。此外，我们的结果表明，R2R3-MYB转录因子BoaMYB28和BoaMYB51分别是脂肪族和吲哚硫代葡萄糖苷生物合成的中心调节因子，均参与褪黑素和UV-B照射对硫代葡萄糖苷生物合成的调节。此外，芥子油苷生物合成基因的表达，包括 、 、 、 、 、 和 参与核心结构的形成，以及 、 、 和 参与脂肪族和吲哚芥子油苷的侧链修饰，受褪黑素或 UV-B 调节辐照。总而言之，这些发现为提高羽衣甘蓝芽的营养质量和抗性提供了潜在的策略。