College of Pharmacy, Heilongjiang University of Chinese Medicine, Harbin, 150040, China.
School of Jiamusi, Heilongjiang University of Chinese Medicine, Harbin, 150000, Heilongjiang, China.
Sci Rep. 2024 Sep 2;14(1):20394. doi: 10.1038/s41598-024-70994-3.
Ginseng, from the roots of Panax ginseng C. A. Meyer, is a widely used herbal medicine in Asian countries, known for its excellent therapeutic properties. The growth of P. ginseng is depend on specific and strict environments, with a preference for wetness but intolerance for flooding. Under excessive soil moisture, some irregular rust-like substances are deposited on the root epidermis, causing ginseng rusty symptoms (GRS). This condition leads to a significant reduce in yield and quality, resulting in substantial economic loses. However, there is less knowledge on the cause of GRS and there are no effective treatments available for its treatment once it occurs. Unsuitable environments lead to the generation of large amounts of reactive oxygen species (ROS). We investigated the key indicators associated with the stress response during different physiological stages of GRS development. We observed a significant change in ROS level, MDA contents, antioxidant enzymes activities, and non-enzymatic antioxidants contents prior to the GRS. Through the analysis of soil features with an abundance of moisture, we further determined the source of ROS. The levels of nitrate reductase (NR) and nitric oxide synthase (NOS) activities in the inter-root soil of ginseng with GRS were significantly elevated compared to those of healthy ginseng. These enzymes boost nitric oxide (NO) levels, which in turn showed a favorable correlation with the GRS. The activities of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase first rose and then decreased as GRS developed. Excess soil moisture causes a decrease in oxygen levels. This activated NR and NOS in the soil, resulting in a production of excess NO. The NO then diffused into the ginseng root and triggered a burst of ROS through NADPH located on the cell membrane. Additionally, Fe in soil was oxidized to red Fe, and finally led to GRS. This conclusion was also verified by the Sodium Nitroprusside (SNP), a precursor compound producing NO. The presence of NO from NR and NOS in water-saturated soil is responsible for the generation of ROS. Among these, NO is the main component that contribute to the occurrence of GRS.
人参是五加科人参属植物，根入药，是亚洲国家广泛使用的草药，具有出色的治疗特性。人参的生长依赖于特定和严格的环境，喜欢潮湿但不能耐受水淹。在土壤水分过多的情况下，一些不规则的锈状物质会沉积在根表皮上，导致人参出现锈斑症状（GRS）。这种情况会导致产量和质量显著下降，造成巨大的经济损失。然而，对于 GRS 的病因知之甚少，一旦发生，也没有有效的治疗方法。不合适的环境会导致大量活性氧（ROS）的产生。我们研究了与 GRS 发展不同生理阶段的应激反应相关的关键指标。我们观察到在 GRS 发生之前，ROS 水平、MDA 含量、抗氧化酶活性和非酶抗氧化剂含量发生了显著变化。通过对富含水分的土壤特征进行分析，我们进一步确定了 ROS 的来源。与健康人参相比，GRS 人参的根际土壤中硝酸还原酶（NR）和一氧化氮合酶（NOS）的活性显著升高。这些酶会提高一氧化氮（NO）的水平，而 NO 水平又与 GRS 呈正相关。随着 GRS 的发展，烟酰胺腺嘌呤二核苷酸磷酸（NADPH）氧化酶的活性先升高后降低。过多的土壤水分会导致氧气水平下降。这激活了土壤中的 NR 和 NOS，导致过量的 NO 产生。然后，NO 扩散到人参根中，通过细胞膜上的 NADPH 引发 ROS 的爆发。此外，土壤中的 Fe 被氧化为红色的 Fe，最终导致 GRS。这一结论也通过产生 NO 的前体化合物硝普酸钠（SNP）得到了验证。在水饱和土壤中，NR 和 NOS 产生的 NO 会导致 ROS 的产生。在这些物质中，NO 是导致 GRS 发生的主要成分。
