Ectomycorrhizal access to organic nitrogen mediates CO2 fertilization response in a dominant temperate tree

• Published in: Nature communications 2021-09, Vol.12 (1), p.5403-5403, Article 5403
• Main Authors: Pellitier, Peter T., Ibáñez, Inés, Zak, Donald R., Argiroff, William A., Acharya, Kirk
• Format: Article
• Language: English
• Subjects: 45; 45/22; 45/23; 631/158/2445; 631/158/853; 704/106/694/2739/2807; 704/158/1144; Availability; Carbon dioxide; Decay; Dendrochronology; Ectomycorrhizas; Fertilization; Fungi; Herbivores; Heterogeneity; Humanities and Social Sciences; Metagenomics; multidisciplinary; Nitrogen; Nutrient availability; Organic matter; Organic nitrogen; Organic soils; Plant growth; Science; Science (multidisciplinary); Soil conditions; Soil investigations; Soil nutrients; Soil organic matter; Soils; Temperate forests; Tree rings; Trees
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-021-25652-x

Plant–mycorrhizal interactions mediate plant nitrogen (N) limitation and can inform model projections of the duration and strength of the effect of increasing CO 2 on plant growth. We present dendrochronological evidence of a positive, but context-dependent fertilization response of Quercus rubra L . to increasing ambient CO 2 (iCO 2 ) along a natural soil nutrient gradient in a mature temperate forest. We investigated this heterogeneous response by linking metagenomic measurements of ectomycorrhizal (ECM) fungal N-foraging traits and dendrochronological models of plant uptake of inorganic N and N bound in soil organic matter (N-SOM). N-SOM putatively enhanced tree growth under conditions of low inorganic N availability, soil conditions where ECM fungal communities possessed greater genomic potential to decay SOM and obtain N-SOM. These trees were fertilized by 38 years of iCO 2 . In contrast, trees occupying inorganic N rich soils hosted ECM fungal communities with reduced SOM decay capacity and exhibited neutral growth responses to iCO 2 . This study elucidates how the distribution of N-foraging traits among ECM fungal communities govern tree access to N-SOM and subsequent growth responses to iCO 2 . Root-mycorrhizal interactions could help explain the heterogeneity of plant responses to CO 2 fertilisation and nutrient availability. Here the authors combine tree-ring and metagenomic data to reveal that tree growth responses to increasing CO 2 along a soil nutrient gradient depend on the nitrogen foraging traits of ectomycorrhizal fungi.