Synthesis and structural characteristics analysis of melanin pigments induced by blue light in Morchella sextelata.

Morchella sextelata, a highly sought-after edible mushroom worldwide, is evaluated based on its cap color as an essential commercial property indicator. In the present study, the effects of blue light on cap pigmentation in M. sextelata, as well as the synthesis and structural characteristics of melanin pigments within the cap were examined. The results showed that an increase in the proportion of blue light within the lighting environment promoted melanin synthesis and melanization of the cap. Transmission and scanning electron microscopy revealed the localization of melanin within the mycelium and its ultrastructural characteristics. The UV-visible analysis demonstrated that melanin exhibited a maximum absorption peak at 220 nm and possessed high alkaline solubility as well as acid precipitability. The structural characteristics of melanin were analyzed using FTIR, NMR, HPLC, and elemental analysis, which confirmed the presence of eumelanin, pheomelanin, and allomelanin in both brown and black caps. Furthermore, blue light can stimulate the synthesis of both eumelanin and pheomelanin. The obtained results can serve as the foundation for comprehending the mechanism by which light regulates color formation in mushrooms.

Comparative analysis of the nutritional and biological properties between the pileus and stipe of Morchella sextelata.

Morchella sextelata is a highly prized edible mushroom and is widely consumed for its distinctive taste and texture. The stipe of M. sextelata is significantly lower in priced compared to the pileus. The aim of this study was to conduct a comprehensive comparative analysis of the nutritional and biological properties between the pileus and stipe of M. sextelata. The results revealed that the stipe exhibited comparable levels of various nutrients and bioactive compounds to those found in the pileus. The stipe showed significantly higher levels of crude dietary fiber, various mineral elements, vitamins, amino acids, 5'-nucleotides, fatty acids, and specific sugars. Additionally, it also demonstrated significant abundance in bioactive compounds such as total flavonoids and ergothioneine. Overall, our study provides valuable insights into unlocking further knowledge about M. sextelata's nutritional composition while highlighting its potential health benefits associated with different parts of this highly esteemed edible mushroom.

Mechanism Underlying Light Intensity-Induced Melanin Synthesis of Auricularia heimuer Revealed by Transcriptome Analysis.

Auricularia heimuer is a traditional edible and medicinal mushroom, which is widely used in biochemical research and is regarded as a good dietary supplement. The color of the ear-like fruiting body is an important indicator of its commercial quality. However, the mechanism by which light intensity influences the melanin synthesis of A. heimuer remains unclear. Here, we show that fruiting body color is significantly affected by light intensity. Transcriptional profiles of the fruiting bodies of A. heimuer grown in different light intensities were further analyzed. More differentially expressed genes (DEGs) were identified with a greater light intensity difference. A total of 1388 DEGs were identified from six comparisons, including 503 up-regulated genes and 885 down-regulated genes. The up-regulated genes were mainly associated with light sensing via photoreceptors, signal transduction via the mitogen-activated protein kinase (MAPK) signaling pathway, and melanin synthesis via the tyrosine metabolic pathway. Therefore, the genes involved in these processes may participate in regulating melanin synthesis under high light intensity. This insight into the transcriptional regulation of A. heimuer to light intensity should help to further comprehensively elucidate the underlying mechanism of light-induced melanin synthesis.