Transcriptional acclimation and spatial differentiation characterize drought response by the ectomycorrhizal fungus Suillus pungens

Changing precipitation regimes are a challenge for forest health under future climate scenarios. If belowground symbionts can acclimate to changing moisture regimes it may buffer forest trees from these changes.
In this study we exposed the ectomycorrhizal fungus Suillus pungens to acute and chronic drought stress and used RNASeq of both ectomycorrhizal roots and extraradical mycelium to gauge the magnitude of stress, identify key genes involved in drought response, and gauge potential ecosystem consequences of drought.
We found that there were major transcriptional differences for S. pungens in ectomycorrhizal roots (28% of genes) and extraradical mycelium (41% of genes) under acute drought stress, but only 0.1-2% of genes were differentially expressed in chronic drought treatments. Up to 56% of differentially expressed genes under acute drought were unique to either roots or mycelium. While a number of implicated genes, such as those encoding for trehalose, have well-known role...