Chen Amanda Juan, Tang Dan, Zhou Ying Qun, Sun Bing Da, Li Xiao Jin, Wang Li Zhi, Gao Wei Wei
Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, P.R. China.
PLoS One. 2013 Oct 21;8(10):e78285. doi: 10.1371/journal.pone.0078285. eCollection 2013.
The presence of fungi on liquorice could contaminate the crop and result in elevated levels of mycotoxin. In this study, the mycobiota associated with fresh and dry liquorice was investigated in 3 producing regions of China. Potential toxigenic fungi were tested for ochratoxin A (OTA) and aflatoxin B1 (AFB1) production using liquid chromatography/mass spectrometry/mass spectrometry. Based on a polyphasic approach using morphological characters, β-tubulin and RNA polymerase II second largest subunit gene phylogeny, a total of 9 genera consisting of 22 fungal species were identified, including two new Penicillium species (Penicillium glycyrrhizacola sp. nov. and Penicillium xingjiangense sp. nov.). The similarity of fungal communities associated with fresh and dry liquorice was low. Nineteen species belonging to 8 genera were detected from fresh liquorice with populations affiliated with P. glycyrrhizacola, P. chrysogenum and Aspergillus insuetus comprising the majority (78.74%, 33.33% and 47.06% of total) of the community from Gansu, Ningxia and Xinjiang samples, respectively. In contrast, ten species belonging to 4 genera were detected from dry liquorice with populations affiliated with P. chrysogenum, P. crustosum and Aspergillus terreus comprising the majority (64.00%, 52.38% and 90.91% of total) of the community from Gansu, Ningxia and Xinjiang samples, respectively. Subsequent LC/MS/MS analysis indicated that 5 fungal species were able to synthesize OTA in vitro including P. chrysogenum, P. glycyrrhizacola, P. polonicum, Aspergillus ochraceus and A. westerdijkiae, the OTA concentration varied from 12.99 to 39.03 µg/kg. AFB1 was absent in all tested strains. These results demonstrate the presence of OTA producing fungi on fresh liquorice and suggest that these fungi could survive on dry liquorice after traditional sun drying. Penicillium chrysogenum derived from surrounding environments is likely to be a stable contributor to high OTA level in liquorice. The harvesting and processing procedure needs to be monitored in order to keep liquorice free of toxigenic fungi.
甘草上存在的真菌可能会污染作物并导致霉菌毒素水平升高。在本研究中，对中国3个产区新鲜和干燥甘草相关的真菌群落进行了调查。使用液相色谱/质谱/质谱法检测了潜在产毒真菌的赭曲霉毒素A（OTA）和黄曲霉毒素B1（AFB1）的产生情况。基于形态特征、β-微管蛋白和RNA聚合酶II第二大亚基基因系统发育的多相方法，共鉴定出9个属的22种真菌，包括两种新的青霉属物种（甘草青霉新种和新疆青霉新种）。新鲜和干燥甘草相关真菌群落的相似度较低。从新鲜甘草中检测到8个属的19种真菌，在甘肃、宁夏和新疆样品中，甘草青霉、产黄青霉和土曲霉所属菌群分别占群落的大部分（分别为78.74%、33.33%和47.06%）。相比之下，从干燥甘草中检测到4个属的10种真菌，在甘肃、宁夏和新疆样品中，产黄青霉、皮落青霉和土曲霉所属菌群分别占群落的大部分（分别为64.00%、52.38%和90.91%）。随后的液相色谱/串联质谱分析表明，5种真菌能够在体外合成OTA，包括产黄青霉、甘草青霉、波兰青霉、赭曲霉和韦斯特迪克曲霉，OTA浓度在12.99至39.03 µg/kg之间。所有测试菌株中均未检测到AFB1。这些结果表明新鲜甘草上存在产OTA真菌，并表明这些真菌在传统晒干后仍能在干燥甘草上存活。来源于周围环境的产黄青霉可能是甘草中OTA高含量的稳定贡献者。需要对收获和加工过程进行监测，以使甘草不含产毒真菌。
