Liu Qing, Wang Fen, Liu Kuanbo, Dong Caihong
State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Beijing, China.
State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.
Int J Med Mushrooms. 2018;20(10):1003-1011. doi: 10.1615/IntJMedMushrooms.2018028582.
Cordyceps militaris is a highly valued edible and medicinal fungus because of its production of various metabolites including adenosine, cordycepin, and N6-(2-hydroxyethyl)-adenosine. Fruiting bodies of this fungus have been used successfully in industrial production and widely as a substitute for Ophiocordyceps sinensis (syn. C. sinensis) in traditional Chinese medicine and health supplements. Strain degeneration occurs with high frequency during the subculturing and preservation of C. militaris strains, which leads to significant losses during industrial production. In this study, we evaluated the effects of different strain preservation methods on fruiting body growth and metabolite production. We found that strain degeneration affects not only fruiting body differentiation but also metabolite production, and suitable preservation methods can avoid degeneration. Preservation in sterile water has a similar effect as cryopreservation in liquid nitrogen at -196°C with regard to maintaining the characteristics of C. militaris strains for at least 1 year, and it is a practical and satisfactory method for preserving C. militaris strains that can be used in factories. Ultracold freezing at -80°C is not suitable for this fungus. Lyophilization, which causes C. militaris strains to retain their inherent characteristics and avoid degeneration, is suitable for long-term preservation (at least 4 years). This study provides practical preservation methods for C. militaris strains over the short and long term and will be helpful to achieve stable and superior-quality production of C. militaris fruiting bodies.
蛹虫草是一种极具价值的食药用真菌，因为它能产生多种代谢产物，包括腺苷、虫草素和N6-(2-羟乙基)-腺苷。这种真菌的子实体已成功用于工业生产，并广泛用作传统中药和保健品中冬虫夏草（同义词：中华虫草菌）的替代品。蛹虫草菌株在继代培养和保藏过程中经常发生退化，这导致工业生产中出现重大损失。在本研究中，我们评估了不同菌株保藏方法对子实体生长和代谢产物产生的影响。我们发现菌株退化不仅影响子实体分化，还影响代谢产物的产生，合适的保藏方法可以避免退化。就保持蛹虫草菌株特性至少1年而言，保存在无菌水中与在-196℃液氮中冷冻保存具有相似的效果，这是一种适用于工厂使用的蛹虫草菌株保藏的实用且令人满意的方法。-80℃超低温冷冻不适合这种真菌。冻干能使蛹虫草菌株保持其固有特性并避免退化，适合长期保存（至少4年）。本研究为蛹虫草菌株提供了短期和长期的实用保藏方法，将有助于实现蛹虫草子实体的稳定和优质生产。
