From White to Reddish-Brown: The Anthocyanin Journey in <i>Stropharia rugosoannulata</i> Driven by Auxin and Genetic Regulators

<i>Stropharia rugosoannulata</i>, or wine-cap Stropharia, is a well-known edible mushroom cultivated globally. The pileipellis color is a crucial quality attribute of <i>S. rugosoannulata</i>, exhibiting significant variation throughout its developmental stages. However, the pigment types and regulatory mechanisms behind color variation remain unclear. The metabolome analysis found that the anthocyanin biosynthesis pathway was significantly enriched and anthocyanins accumulated steadily in fruiting bodies during three developmental stages. The pileipellis pigment was extracted, and HPLC-MS confirmed the presence of anthocyanins. Notably, significant differences in anthocyanin content were observed among the various colored varieties. Thus, anthocyanins contribute to the pileipellis color of <i>S. rugosoannulata</i>. Through further investigation, this study elucidated, for the first time, the relationship between the "SrNFYA-<i>SrDRF2</i>" regulatory module and anthocyanin accumulation. Combined multiomics assays and HPLC analysis revealed that auxin functions as a signaling molecule that regulates the accumulation of anthocyanins in the pileipellis. Subsequently, the hub gene of anthranilate synthase for auxin synthesis was identified as <i>SrTRP1,</i> and the transcription factor SrMYB1 was verified as a regulator of <i>SrTRP1</i>, influencing auxin accumulation. These findings provide a valuable resource for the targeted enhancement of the quality of <i>S. rugosoannulata</i>.