Objective By further measuring the amino acid content and identifying the selenium forms of Morchella sextelatam under different selenium concentrations, the suitable selenium concentration for artificial cultivation of Morchella sextelatam was ultimately selected, providing methodological guidance for the further development of selenium rich Morchella sextelatam products.

Methods This study artificially cultivated Morchella sextelatam under different concentrations of exogenous selenium, measured the content of various amino acids in their fruiting bodies, and evaluated the correlation between various amino acids in Morchella sextelatam and the effect of selenium concentration on the comprehensive level of amino acids in Morchella sextelatam through correlation analysis and principal component analysis. Selenium forms were also identified.

Results The results showed that when the concentration of selenium was 0.0~40.0 mg/L, the total amino acid content of Morchella sextelatam was between 20.86% and 22.53%, among which the maximum was at 0.0 mg/L selenium, and the minimum was at 40.0 mg/L selenium. When selenium concentration was 40.0 mg/L, the proportion of essential amino acids in total amino acids showed the highest, which was 38.45%. Through the analysis of flavor amino acid composition, the total proportion of fresh sweet amino acids in the four groups of Morchella sextelatam was higher than that of bitter amino acids, with fresh sweet as the main flavor. Through correlation analysis, it was found that the majority of amino acids in Morchella are positively correlated, with some amino acids showing significant correlation (P<0.05) and some amino acids showing extremely significant correlation (P<0.01). According to the comprehensive evaluation of principal component analysis, with the increase of selenium concentration, the comprehensive level of various amino acids in Morchella sextelatam decreased, and the addition of exogenous selenium would affect the content of amino acids. According to the detection of Se element in fruit bodies, it was found that the content of Se needed by human body increased along with the increase of selenium concentration. SeCys₂, Se(Ⅳ) and Se(Ⅵ) were not detected in the fruiting bodies of Morchella sextelatam at selenium concentrations of 20.0 and 40.0 mg/L. When the selenium concentration was 20.0 mg/L, the SeMet content was 1.98 mg/kg, accounting for 17.89% of the total selenium content; when the selenium concentration was 40.0 mg/L, the SeMet content was 8.00 mg/kg, accounting for 24.94% of the total selenium content. Based on the results of amino acid contents and selenium forms, 20.0 mg/L of selenium concentration was most suitable for artificial cultivation of selenium-enrich morel.

Conclusion In summary, selenium concentrations of 20.0 and 40.0 mg/L can both be used as suitable selenium concentrations for selenium rich artificial cultivation of Morchella sextelatam. The essential amino acid content in the treated Morchella sextelatam is relatively high, and the overall level of various amino acid contents is relatively low; SeMet is the main form of selenium, with contents of 1.980 and 8.000 mg/kg, respectively; This study provides technical support for optimizing the cultivation of selenium-rich Morchella sextelatam and developing selenium-rich products in the future.