Salt stress has long been a prominent obstacle that restricts crop growth, and increasing the L-ascorbic acid (ASA) content of crops is an effective means of alleviating this stress. 2-Keto-L-gulonic acid (2KGA) is a precursor used in industrial ASA production as well as an ASA degradation product in plants. However, to date, no study has investigated the effects of 2KGA on ASA metabolism and salt stress. Here, we evaluated the potential of using 2KGA to improve crop resistance to salt stress (100mM NaCl) through a cultivation experiment of non-heading Chinese cabbage (Brassica campestris ssp. chinensis). The results showed that the leaf and root biomass were significantly improved by 2KGA application. The levels of metabolites and enzymes related to stress resistance were increased, whereas the hydrogen peroxide (H₂O₂) and malondialdehyde (MDA) contents were decreased. Lipid peroxidation and cell membrane damage were alleviated following 2KGA treatment. Positive correlations were found between photosynthetic pigments and organic solutes, ASA and photosynthetic pigments, and ASA and antioxidant enzymes. In contrast, negative correlations were observed between antioxidant enzymes and H₂O₂/MDA. Moreover, the expression levels of L-gulono-1,4-lactone oxidase, GDP-mannose pyrophosphorylase, dehydroascorbate reductase-3, and ascorbate peroxidase were increased by 2KGA treatment. These results suggested that exogenous 2KGA application can relieve the inhibitory effect of salt stress on plant growth, and the promotion of ASA synthesis may represent a critical underlying mechanism. Our findings have significant implications for the future application of 2KGA or its fermentation residue in agriculture.

盐胁迫长期以来一直是制约作物生长的突出障碍，提高作物的L-抗坏血酸（ASA）含量是缓解这种胁迫的有效手段。2-酮-L-古洛糖酸 (2KGA) 是工业 ASA 生产中使用的前体，也是植物中的 ASA 降解产物。然而，迄今为止，还没有研究调查 2KGA 对 ASA 代谢和盐胁迫的影响。在这里，我们通过不结球白菜的栽培实验评估了使用 2KGA 提高作物对盐胁迫（100mM NaCl）抗性的潜力（油菜 ssp。 中华）。结果表明，施用2KGA显着提高了叶和根生物量。与抗逆性相关的代谢物和酶的水平增加，而过氧化氢（H ₂ O ₂）和丙二醛（MDA）的含量降低。2KGA 处理后脂质过氧化和细胞膜损伤得到缓解。发现光合色素与有机溶质、ASA 与光合色素、ASA 与抗氧化酶之间呈正相关。相反，在抗氧化酶和H ₂ O ₂ /MDA之间观察到负相关。此外，表达水平L-gulono-1,4-内酯氧化酶, GDP-甘露糖焦磷酸化酶, 脱氢抗坏血酸还原酶-3， 和 抗坏血酸过氧化物酶2KGA 处理增加。这些结果表明外源 2KGA 应用可以减轻盐胁迫对植物生长的抑制作用，促进 ASA 合成可能是一个关键的潜在机制。我们的发现对未来 2KGA 或其发酵残留物在农业中的应用具有重要意义。