Metatranscriptomics captures dynamic shifts in mycorrhizal coordination in boreal forests

Area of Science:

• Ecology
• Forestry
• Microbiology

Background:

• Boreal forests are critical terrestrial carbon sinks.
• Tree-microbe interactions regulate carbon cycling but are poorly understood under environmental change.
• Predicting ecosystem services requires understanding these complex relationships.

Purpose of the Study:

• To investigate the impact of nutrient enrichment on Norway spruce fine roots and associated fungal communities.
• To analyze changes in fungal community structure, function, and tree-microbe coordination.
• To provide mechanistic insights into host-microbe molecular dialogue.

Main Methods:

• Developed a metatranscriptomic approach.
• Analyzed over 350 root-associated fungal species in Norway spruce.
• Examined transcriptional coordination between host trees and fungi.

Main Results:

• Nutrient enrichment altered host tree defense and sugar transport.
• Fungal community structure shifted, with decreased coordination with Basidiomycetes and increased coordination with Ascomycetes.
• Dominance shifted from carbon-cycling Basidiomycetes to degradation-resistant Ascomycetes.

Conclusions:

• Host-microbe dynamics are sensitive to nutrient availability.
• Functional shifts in fungal communities can alter carbon storage potential in boreal soils.
• Understanding these molecular dialogues is key to predicting forest ecosystem responses to climate change.