Effects of nano-selenium on mycelial growth, agronomic traits, and nutritional quality of Stropharia. rugosoannulata

Stropharia rugosoannulata is one of the most popular edible fungi species in the world. However, the regulatory effects of selenium on the growth and nutritional quality of S. rugosoannulata remain insufficiently understood. This study investigated the selenium content, speciation and the effect of selenium on mycelial growth, agronomic traits, nutritive value and antioxidant enzyme activities in S. rugosoannulata . The results showed that nano-selenium exerted a “low-promotion, high-inhibition” effect on S. rugosoannulata . Selenium at 2-20 mg/kg significantly promoted mycelial growth of S. rugosoannulata , whereas concentrations exceeding 40 mg/kg suppressed growth. During fruiting body development, selenium at 20-30 mg/kg significantly increased the yield, optimized morphological stability, and elevated levels of crude polysaccharides (+15.73%), crude proteins (+37.96%), and crude fats (+177.78%). S. rugosoannulata accumulated 306.017 mg/kg selenium upon treatment with 40 mg/kg nano-selenium, of which over 97% was organic selenium, predominantly selenomethionine. The activities of CAT, POD, and SOD exhibited a U-shaped response, characterized by an initial decrease followed by an increase as selenium concentrations rose. And, the optimal concentration for S. rugosoannulata cultivation was determined to be 30 mg/kg nano-selenium based on PCA results. This study establishes a theoretical foundation for the product development and quality improvement of selenium-enriched S. rugosoannulata.