This study examined how Lyophyllum decastes mushrooms develop and build up their nutritious compounds. Researchers tracked amino acids and polysaccharides across four growth stages and identified which genes control their production. The mature mushrooms contained the highest levels of beneficial compounds, with amino acids reaching 45,107.39 μg/g and polysaccharides at 13.66 mg/g. These findings help explain why these mushrooms are nutritious and suggest ways to grow them better for maximum health benefits.