Metatranscriptomics captures dynamic shifts in mycorrhizal coordination in boreal forestsLaw, Simon; Serrano, Alonso; Daguerre, Yohann; Sundh, John; Schneider, Andreas N.; Stangl, Zsofia Réka; Stangl , Zsofia Reka; Castro, David; Grabherr, Manfred G.; Näsholm, Torgny; Street, Nathaniel R.; Hurry, Vaughan
Carbon storage and cycling in boreal forests—the largest terrestrial carbon store—ismoderated by complex interactions between trees and soil microorganisms. However,existing methods limit our ability to predict how changes in environmental conditionswill alter these associations and the essential ecosystem services they provide. To addressthis, we developed a metatranscriptomic approach to analyze the impact of nutrientenrichment on Norway sprucefine roots and the community structure, function, andtree–microbe coordination of over 350 root-associated fungal species. In response toaltered nutrient status, host trees redefined their relationship with the fungal commu-nity by reducing sugar efflux carriers and enhancing defense processes. This resulted ina profound restructuring of the fungal community and a collapse in functional coordi-nation between the tree and the dominant Basidiomycete species, and an increase infunctional coordination with versatile Ascomycete species. As such, there was a func-tional shift in community dominance from Basidiomycetes species, with importantroles in enzymatically cycling recalcitrant carbon, to Ascomycete species that have mela-nized cell walls that are highly resistant to degradation. These changes were accompa-nied by prominent shifts in transcriptional coordination between over 60 predictedfungal effectors, with more than 5,000 Norway spruce transcripts, providing mechanis-tic insight into the complex molecular dialogue coordinating host trees and their fungalpartners. The host–microbe dynamics captured by this study functionally inform howthese complex and sensitive biological relationships may mediate the carbon storagepotential of boreal soils under changing nutrient conditions.
Keywordsmetatranscriptome; host–microbe; ectomycorrhiza; carbon storage; fungal effectors
Published inProceedings of the National Academy of Sciences of the United States of America
2022, volume: 119, number: 26, article number: e2118852119
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