Decoding the Bioluminescent and Non-Bioluminescent Traits of Panellus stipticus: A Genomic and Phenotypic Perspective

The species Panellus stipticus presents a unique situation whereby some geographic strains are bioluminescent while others are not. This study investigates the factors affecting the bioluminescence of P. stipticus, focusing on culture media optimization, oxygen dependency, and genetic variation between luminescent and non-luminescent strains. Experiments revealed that 10% breadcrumb agar (BCA) significantly enhanced bioluminescence and colony size while supplementation with activated charcoal reduced luminescence. Comparative analysis of carbohydrate-based media showed that BCA outperformed malt extract and molasses in promoting luminescence. Oxygen was confirmed as essential for bioluminescence, with light emission ceasing rapidly under anaerobic conditions and recovering within minutes upon re-exposure to air. Phylogenetic analysis using ITS sequences distinguished luminescent and non-luminescent strains, aligning with biogeographical patterns. Dot plot synteny analysis of draft genomes of a bioluminescent (Panst LUM) and a non-bioluminescent strain (KUC8834) revealed high genomic conservation. However, absence of key bioluminescence genes in non-luminescent strains explains their lack of light emission. Protein sequence comparisons of core enzymes-LUZ, HISP, and H3H-showed functional similarity with Mycenoid lineage species. These findings deepen our understanding of fungal bioluminescence and its genetic and environmental determinants.