The multifunctional fungus Phanerochaete chrysosporium enriches metabolites while degrading seed mucilage of a sand-fixing shrub.

Aims: The sand-fixing desert shrub Artemisia sphaerocephala produces a large amount of seed mucilage, which plays crucial roles in the adaptation of this species to desert environments. Seed mucilage has been shown to be degraded by Phanerochaete chrysosporium from habitat soils, but the process and products of this degradation remain unclear. To fill this gap, we explored the factors and processes involved in mucilage degradation.

Methods And Results: We found that P. chrysosporium had the ability to produce iron carriers and to solubilize potassium and phosphorus. Mucilage degradation was affected by multiple factors, and the optimum conditions for mucilage degradation were 30°C, pH 4.5, 10 ml of fungal solution, and 1.0 g of mucilage substrate, with a degradation rate of 93.04% ± 4.87% at 20 days. The untargeted metabolome screened 300 significantly different metabolites during mucilage degradation, of which 291 were upregulated and 9 downregulated. The main degradation products were organoxides, lipids, lipid-like molecules, phenylpropanoids, polyketides, and organic acids. The most significantly affected pathway was the valine, leucine, and isoleucine biosynthetic pathway.

Conclusions: Our study has elucidated the mucilage degradation process and metabolites, which may help us to better understand the ecological functions of seed mucilage and the mechanisms of plant-microbe interactions in deserts.