How Mycorrhizal Fungi Speed Up Forest Litter Decomposition Through Enzyme and Gene Regulation

New Research Shows How Mycorrhizal Fungi Accelerate Forest Litter Breakdown by Regulating Microbial Enzymes and Genes

A new study published in Plant and Soil reveals that arbuscular mycorrhizal fungi (AMF) play a much stronger role in forest nutrient cycling than previously understood. The research demonstrates that AMF not only enhance litter decomposition rates but do so by altering microbial enzyme activities and boosting the abundance of specific carbon- and phosphorus-cycling genes.

Using a 200-day microcosm experiment, researchers examined how Funneliformis mosseae interacted with decomposing Symplocos lucida leaf litter. The results show that AMF increased litter mass loss by 10.3%, leading to significantly faster nutrient turnover.

The fungi achieved this by upregulating key microbial genes such as abfA, exg, manB, xylA, phoC, and phoD, which encode enzymes responsible for breaking down cellulose, hemicellulose, and organic phosphorus. Correspondingly, enzyme activities including β-glucosidase, N-acetylglucosaminidase, and acid phosphatase were significantly elevated in AMF-treated systems.

These enzyme-gene interactions also affected soil nutrient dynamics. AMF-inoculated systems showed higher early-stage soil organic carbon and nitrogen, while phosphorus availability declined due to active fungal uptake—indicating strong fungal involvement in nutrient redistribution. Importantly, AMF reduced microbial phosphorus limitation during early decomposition phases and maintained high phosphatase activity later on.

The study’s path modeling further revealed that AMF influence up to 79% of variation in litter mass loss, highlighting their significant ecological function in subtropical forests.

This work provides compelling evidence that AMF do more than transport nutrients to plants—they actively shape the microbial machinery that powers forest nutrient cycling. These insights expand our understanding of carbon and phosphorus coupling in nutrient-limited ecosystems.

Reference

Wang, W., Wu, X., Tang, Y., Yang, Y., Liang, Q., & Hu, K. (2025). Arbuscular mycorrhizal fungi mediate litter decomposition by altering enzyme activity and microbial functional gene abundance. Plant and Soil. https://doi.org/10.1007/s11104-025-07863-z