Fungal adaptation to nutrient cyclings of vegetations is observed along forest chronosequence. However, the mechanisms behind plant-fungus interactions in controlling carbon (C) and nitrogen (N) acquisition and allocation need to be uncovered.
The scientists from Research Group of Biodiversity in Institute of Applied Ecology (IAE) of the Chinese Academy of Sciences (CAS) conducted an in situ study to investigate the seral shifts of litter and soil C and N contents and of soil fungal communities along a 30a-100a succession gradient of a subtropical forest ecosystem in Xishuangbanna, southwestern China.
The changes in litter N content were highly relevant to fungal diversity and the relative abundances of saprotroph and arbuscular mycorrhizal (AM) fungi, while the shift in ectomycorrhizal (EcM) fungal relative abundance was in line with that of litter C content. Simultaneously, the soil total C and N, water-soluble C and N, and C/N ratios declined with stand age, while the abundances of Zygomycota, Rozellomycota, Chytridiomycota and the C and N use efficiencies of microbial communities increased at late-succession stages.
In addition, the multiple linear regression and multivariate analysis showed that the litter C content was negatively correlated with the fungal richness and saprotroph abundance or positively correlated with the abundance of EcM fungi; in contrast, the litter N content presented the exact opposite trend. The variances in the relative abundances of Zygomycota, Rozellomycota and AM fungi were negatively correlated with the water-soluble C content but positively correlated with the water-soluble N content in soil.
Consequently, their results evidence that the enrichment and depletion of available nutrients are controlled by plant-fungus interaction, which is closely mediated by litter and soil C:N stoichiometry along the forest chronosequence. In particular, shifts in fungal community structure are closely determined by the trade-off between EcM-fungi-dominated nutrient storage/deposition and saprotrophic/AM-fungi-dominated nutrient consumption/retrieval associated with forest succession stages. In fact, it is fitness improvement and nutrient acquisition that universally control site-specific C and N cyclings as well as the plant nutrient acquisition and microbial strategy-dependent feedbacks in forest ecosystems.
The results were published in CATENA entitled “Litter-, soil- and C:N-stoichiometry-associated shifts in fungal communities along a subtropical forest succession”.
Their work was supported by NNSFC and China Soil Microbiome Initiative of the CAS.
