Divergent transcriptional responses of conserved cellular machinery to warming and phosphorus limitation in freshwater phytoplankton

Ribosome- and translation-related gene expression showed the strongest warming response in freshwater phytoplankton, but its direction diverged across species and even within Nitzschia palea across 20–24–28°C.

• Why it matters: Lakes face simultaneous warming and phosphorus limitation, yet it is unclear whether conserved cellular machinery responds similarly across taxa, undermining common assumptions used in ecological forecasting.
• What they did: Four freshwater phytoplankton species (two diatoms and two cyanobacteria) were cultured across temperature (20, 24, 28°C) and phosphorus limitation gradients, then analyzed by RNA-seq with differential expression and signed gene set enrichment.
• The result: Warming and phosphorus limitation engaged largely predicted functional categories, but response direction was not conserved; phosphorus limitation rarely added new pathways, instead suppressing warming responses in Fragilaria crotonensis and amplifying/redirecting them in Microcystis aeruginosa.