为研究发光二极管（Light-Emitting Diodes，LED）处理对上海青采后硫代葡萄糖苷（简称硫苷）代谢的作用机理，该研究首先采用不同颜色和光密度的光照处理上海青，得出6.5 μmol/(m2•s)的红色LED光照处理可显著抑制上海青中叶绿素降解，延缓其黄化。在此基础上，研究了6.5 μmol/(m2•s)红色LED光照处理对贮藏期间上海青中硫苷代谢相关物质及基因表达水平的影响。结果表明，上海青叶柄中总硫苷和异硫氰酸酯含量分别为叶片的2.72倍和1.32倍；红色LED光照处理可显著上调上海青叶柄中脂肪族合成关键基因MYB28、CYP83A1、GSTF11等的表达水平，从而促进叶柄中主要硫苷物质3-丁烯基硫苷等的合成；由此，上海青叶柄中总硫苷含量在贮藏4~8 d期间为对照组的1.62~1.99倍；同时，该处理提升了上海青叶柄的黑芥子酶活性，从而促进了总异硫氰酸酯的积累，且在贮藏4~8 d期间，对照组上海青叶柄的总异硫氰酸酯含量为红光处理组的77.43%~91.98%。综上，红色LED光照处理通过调控硫苷合成关键基因和黑芥子酶活性来延缓上海青中硫苷物质和异硫氰酸酯的流失。

Light-emitting diode (LED) irradiation with different colors and densities was employed for investigating the effect of red light on glucosinolate metabolism in postharvest pakchoi (Brassica rapa L subsp. chinensis). The results showed that both chlorophyll degradation and pakchoi yellowing were inhibited by red LED irradiation at a density of 6.5 μmol/(m2•s). Subsequently, the changes in glucosinolate content and relative expression level of genes involved in the glucosinolate metabolism of pakchoi after red LED irradiation (6.5 μmol/m2•s) were analyzed to explore the underlying regulatory mechanism. The results indicated that the contents of total glucosinolate and isothiocyanate in pakchoi petiole were 2.72 and 1.32 times higher than those in leaves, respectively. Additionally, the expression of key aliphatic synthesis genes, including MYB28, CYP83A1, and GSTF11, was significantly upregulated by red LED irradiation, thus promoting the synthesis of glucosinolate such as 3-butenyl glucosinolate. Consequently, the total glucosinolate content in treated pakchoi petiole was 1.62~1.99 times higher than that in the control during 4~8 d of storage. The myrosinase activity was promoted, and consequently, the accumulation of total isothiocyanate was increased in pakchoi petiole following red LED irradiation. Notably, the total isothiocyanate content in the control group was 77.43%~91.98% lower than that in the irradiated group during 4~8 d. In conclusion, red LED light treatment delayed the loss of glucosinolates and isothiocyanates in pakchoi, as indicated by the upregulated relative gene expression levels involved in the synthesis of aliphatic glucosinolate and increased myrosinase activity.

江苏省农业科技自主创新资金项目（CX(20)3046）；江苏省现代农业-面上项目（BE2022368）