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Background and aims <p>Arbuscular mycorrhizal fungi (AMF) are known to influence litter decomposition, but the mechanisms involving microbial functional genes and enzyme activities remain unclear. We tested whether AMF regulate decomposition by enhancing microbial carbon (C) and phosphorus (P) mineralization potential, and explored their implications for nutrient redistribution in subtropical forest soils.</p> Methods <p>We conducted a 200-day dual-compartment microcosm experiment. The planting compartment contained <i>Lolium multiflorum</i> with or without <i>Funneliformis mosseae</i>, and the litter compartment contained leaf litter of <i>Symplocos lucida</i>, a dominant canopy species in subtropical forests. <i>L. multiflorum</i> served as a functional analog of fast-growing understory vegetation.</p> Results <p>AMF hyphae increased Litter mass loss by 10.3% (<i>p</i> &lt; 0.05) and altered soil organic carbon, total nitrogen, and available phosphorus dynamics. PLS-PM modeling (GOF = 0.71) revealed that AMF directly and indirectly promoted decomposition by upregulating microbial genes (<i>abfA</i>, <i>exg</i>, <i>manB</i>, <i>xylA</i>, <i>phoC</i>, and <i>phoD</i>) and enzyme activity (β-glucosidase, N-acetylglucosaminidase, and acid phosphatase). Gene abundances showed strong positive correlations with corresponding enzyme activities (<i>r</i> = 0.65–0.79, <i>p</i> &lt; 0.01). AMF reduced microbial P Limitation during the first 140&#xa0;days and sustained phosphatase gene expression and activity thereafter. Lignin-degrading enzyme activity was positively correlated with refractory C mineralization genes.</p> Conclusion <p>AMF accelerated litter decomposition by modulating microbial functional potential in a stage-specific manner, linking C- and P-mineralization through coordinated gene expression and enzyme activity. By alleviating nutrient limitations, particularly P, AMF enhanced soil nutrient mineralization and nutrient redistribution, thereby contributing to coupled C and P cycling in P-limited subtropical forests.</p>

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Arbuscular mycorrhizal fungi mediate litter decomposition by altering enzyme activity and microbial functional gene abundance

  • 期刊论文

  • 发表日期：

    2025年10月25日

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  • Wei Wang,
  • Xiaogang Wu,
  • Yongxin Tang,
  • Yikai Yang,
  • Qin Liang,
  • Kai Hu

摘要

Background and aims

Arbuscular mycorrhizal fungi (AMF) are known to influence litter decomposition, but the mechanisms involving microbial functional genes and enzyme activities remain unclear. We tested whether AMF regulate decomposition by enhancing microbial carbon (C) and phosphorus (P) mineralization potential, and explored their implications for nutrient redistribution in subtropical forest soils.

Methods

We conducted a 200-day dual-compartment microcosm experiment. The planting compartment contained Lolium multiflorum with or without Funneliformis mosseae, and the litter compartment contained leaf litter of Symplocos lucida, a dominant canopy species in subtropical forests. L. multiflorum served as a functional analog of fast-growing understory vegetation.

Results

AMF hyphae increased Litter mass loss by 10.3% (p < 0.05) and altered soil organic carbon, total nitrogen, and available phosphorus dynamics. PLS-PM modeling (GOF = 0.71) revealed that AMF directly and indirectly promoted decomposition by upregulating microbial genes (abfA, exg, manB, xylA, phoC, and phoD) and enzyme activity (β-glucosidase, N-acetylglucosaminidase, and acid phosphatase). Gene abundances showed strong positive correlations with corresponding enzyme activities (r = 0.65–0.79, p < 0.01). AMF reduced microbial P Limitation during the first 140 days and sustained phosphatase gene expression and activity thereafter. Lignin-degrading enzyme activity was positively correlated with refractory C mineralization genes.

Conclusion

AMF accelerated litter decomposition by modulating microbial functional potential in a stage-specific manner, linking C- and P-mineralization through coordinated gene expression and enzyme activity. By alleviating nutrient limitations, particularly P, AMF enhanced soil nutrient mineralization and nutrient redistribution, thereby contributing to coupled C and P cycling in P-limited subtropical forests.