ATP deficiency triggers ganoderic acids accumulation via fatty acid β-oxidation pathway in Ganoderma lucidum.

Background: Ganoderic acids (GAs), recognized as significant triterpenoid bioactive components in Ganoderma lucidum, exhibit a broad spectrum of pharmacological activities, including immunomodulation, anti-cancer, and anti-aging properties. Despite their significant pharmacological potential, the low yield of GAs from natural sources has emerged as a critical bottleneck hindering their broader application in the pharmaceutical and health care industries. Previous studies have suggested that environmental perturbations can influence energy metabolism, potentially impacting the biosynthesis of bioactive compounds. However, the specific influence of environmental changes on energy metabolism and subsequent effects on GAs synthesis in G. lucidum remains an understudied area.

Results: We demonstrated that intracellular ATP deficiency significantly influences GAs accumulation induced by alterations in energy metabolism. Intracellular ATP deficiency was consistently observed under all four known conditions that induce GAs accumulation: heat stress (HS), nitrogen limitation, treatment with 50 µM methyl jasmonate (MeJA), and treatment with 200 µM salicylic acid (SA). Consistent with these findings, silencing the ATP synthase beta subunit (ATPsyn-beta) or treating with oligomycin (Oli), an ATP synthase inhibitor, increased GAs accumulation and induced intracellular ATP deficiency in G. lucidum. Our results revealed an increase in the GAs biosynthetic pathway and increased levels of the GAs precursor acetyl-CoA in mycelia with intracellular ATP deficiency. Enhanced fatty acid β-oxidation was identified as the primary source of additional acetyl-CoA, indicating that this process, induced by intracellular ATP deficiency, is crucial for GAs accumulation.

Conclusions: This study demonstrated that changes in intracellular ATP content respond to environmental perturbations and impact the biosynthesis of GAs, holding substantial implications for production practices. Modulating ATP levels could increase GAs yields, cater to market demands, and reduce costs. The research also furnishes a scientific foundation for optimizing cultivation conditions, employing genetic engineering to refine biosynthetic pathways, and leveraging environmental control to boost production efficiency.