Transcriptome sequencing reveals iron acquisition–related genes and iron acquisition systems in Auricularia cornea

Auricularia cornea exhibits significant potential for iron-enrichment. However, the mechanisms behind iron absorption and accumulation remain poorly understood. This study employed biochemical and transcriptomic approaches to systematically investigate the effects of an iron-rich environment on iron accumulation in A. cornea across 3 growth stages, as well as to characterize its iron acquisition–related (IAR) genes and iron acquisition systems. Our findings showed that A. cornea can produce siderophores. Supplementation with Fe₂(SO₄)₃ markedly increased iron content in both mycelia and primordia. Transcriptomic analysis revealed that iron supplementation significantly altered the expression of key IAR genes during the mycelial stage, but not in the primordia and fruiting body stages. Nine key IAR genes were identified, indicating that A. cornea possesses the molecular basis for the iron accumulation via reductive and non-reductive iron acquisition systems and ferrous transport systems. Phylogenetic analysis revealed that proteins involved in iron transport were highly conserved across Basidiomycota and Ascomycota, whereas those with redox functions have undergone divergence. These results provide new insights into the iron acquisition in A. cornea.