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.

Spawn aging poses a substantial challenge to the Agaricus bisporus industry. This study focuses on the role of mitochondrial dysfunction in the aging process of A. bisporus spawn. We conducted a comprehensive comparative transcriptome analysis to elucidate the molecular mechanisms underlying A. bisporus spawn aging. A total of 1620 genes with significant expression changes between the normal and aged spawn were identified, including 917 up-regulated genes and 703 down-regulated genes. Our results revealed a notable down-regulation of genes involved in carbohydrate metabolism, mitochondrial energy metabolism, reactive oxygen species (ROS) scavenging, repair mechanisms for oxidative stress-induced damage, fatty acid β-oxidation, and amino acid degradation in aged A. bisporus spawn. Additionally, we observed a decreased expression of genes involved in critical signal transduction pathways associated with mitochondrial function in aged mycelium as well as genes responsible for maintaining mitochondrial stability. The up-regulated genes in aged spawn mainly affect mitochondrial fission and programmed cell death, impacting mitochondrial function. Overall, the present study first provides evidence for the pivotal role of mitochondrial dysfunction in the aging process of A. bisporus spawn and contributes to the development of targeted strategies to enhance mitochondrial function, mitigate spawn aging, and improve the yield and quality of A. bisporus cultivation.

Sparassis latifolia thrives in natural Pinus koraiensis (Korean Pine) forests, but its artificial cultivation remains inefficient due to poor substrate utilization. Its nutritional strategy, long presumed to be saprotrophic, is poorly defined, impeding domestication efforts. We integrated taxonomic identification, pathogenicity assays, computerized tomography scanning, laser scanning microscope, Scanning electron microscopy (SEM)/Transmission electron microscopy (TEM) visualization of root colonization, and carbon utilization profiling to elucidate S. latifolia’s trophic mode. By analysis the morphological characteristics of the basidiocarps and the isolations from infected roots, and in combination with molecular data, identified as S. latifolia. This fungus was demonstrated pathogenic on P. koraiensis seedlings, causing root rot with intracellular colonization of sieve cells. Mycelial growth was quantified in minimal media supplemented with host-derived compounds. S. latifolia showed striking carbon source specificity, growing significantly only on glucose or monolignol glucoside coniferin. Coniferin drove faster radial expansion and higher biomass yield than glucose. This specificity correlates with high coniferin levels in fresh P. koraiensis lateral roots, markedly reduced in dried substrates. Our findings provide strong evidence supporting S. latifolia as a facultative parasite of P. koraiensis, reliant on host-derived coniferin as a premium carbon source. This coniferin-centric strategy underpins its efficient colonization in living roots and may partially explains long cultivation cycle in coniferin-decreased artificial substrates. Our findings resolve its nutritional ecology and expose the critical bottleneck for domestication.