Data_Sheet_1_The sweating process promotes toxigenic fungi expansion and increases the risk of combined contamination of mycotoxins in Radix Dipsaci.PDF

Sweating is one of the most important processing methods of Chinese medicinal herbs. However, the high temperature and humidity environment required for sweating Chinese medicinal herbs makes it very easy for fungi to breed, especially toxigenic fungi. The mycotoxins produced by these fungi will then contaminate the Chinese medicinal herbs. In this study, we explored the changes in mycobiota, toxigenic fungi, and mycotoxins with and without sweating in Radix Dipsaci (RD), a typical representative of traditional Chinese medicine that requires processing through sweating. We also isolated and identified the toxigenic fungi from RD, whether they were subjected to sweating treatment or not, and examined their toxigenic genes and ability. The results showed that the detection rate of mycotoxins (aflatoxins, ochratoxins, zearalenone, and T-2 toxin) in RD with sweating was 36%, which was 2.25-fold higher than that in RD without sweating. We also detected T-2 toxin in the RD with sweating, whereas it was not found in the RD without sweating. The sweating process altered the fungal composition and increased the abundance of Fusarium and Aspergillus in RD. Aspergillus and Fusarium were the most frequently contaminating fungi in the RD. Morphological and molecular identification confirmed the presence of key toxigenic fungal strains in RD samples, including A. flavus, A. westerdijkiae, F. oxysporum and F. graminearum. These four fungi, respectively, carried AflR, PKS, Tri7, and PKS14, which were key genes for the biosynthesis of aflatoxins, ochratoxins, zearalenone, and T-2 toxin. The toxigenic ability of these four fungal strains was verified in different matrices. We also found that A. flavus, A. westerdijkiae, and F. oxysporum were isolated in RD both with sweating and without sweating, but their isolation frequency was significantly higher in the RD with sweating than in the RD without sweating. F. graminearum was not isolated from RD without sweating, but it was isolated from RD with sweating. These findings suggest that the sweating process promotes the expansion of toxigenic fungi and increases the risk of combined mycotoxin contamination in RD.

发汗是中药材最为重要的加工方法之一。然而，中药材发汗所需的高温高湿环境极易滋生真菌，尤其是产毒真菌。这些真菌产生的真菌毒素会进而污染中药材。
本研究以需经发汗加工的典型中药材川续断根（Radix Dipsaci, RD）为研究对象，探究了发汗处理与未发汗处理的川续断根中真菌群落、产毒真菌及真菌毒素的变化情况。同时，本研究对发汗与未发汗处理的川续断根中的产毒真菌进行分离鉴定，并检测了其产毒基因与产毒能力。
研究结果显示，经发汗处理的川续断根中真菌毒素（黄曲霉毒素、赭曲霉毒素、玉米赤霉烯酮及T-2毒素）的检出率为36%，较未发汗处理组提升2.25倍。此外，发汗处理组的川续断根中检出了T-2毒素，而未发汗处理组未检出该毒素。发汗过程改变了川续断根中的真菌群落组成，提升了镰孢菌属（Fusarium）与曲霉属（Aspergillus）的丰度。曲霉属与镰孢菌属是川续断根中最常见的污染真菌。
形态学与分子鉴定结果证实，川续断根样本中存在关键产毒真菌菌株，包括黄曲霉（A. flavus）、威斯特丹曲霉（A. westerdijkiae）、尖孢镰孢菌（F. oxysporum）以及禾谷镰孢菌（F. graminearum）。这四种真菌分别携带了黄曲霉毒素、赭曲霉毒素、玉米赤霉烯酮及T-2毒素生物合成的关键基因AflR、PKS、Tri7及PKS14。本研究在不同基质中验证了这四种真菌菌株的产毒能力。
研究同时发现，发汗与未发汗处理的川续断根中均分离得到黄曲霉、威斯特丹曲霉及尖孢镰孢菌，但发汗处理组的分离频率显著高于未发汗处理组。禾谷镰孢菌未在未发汗处理的川续断根中分离得到，但在发汗处理组中成功分离。上述研究结果表明，发汗加工过程会促进产毒真菌的增殖，提升川续断根中真菌毒素复合污染的风险。