Transcriptional frontloading contributes to cross-tolerance between stressors

Area of Science:

• Environmental science
• Ecology
• Molecular biology

Background:

• Phenotypic plasticity is crucial for single-stressor adaptation.
• Cross-tolerance, or resilience to different stressors, is key in complex natural environments.
• Understanding cross-tolerance mechanisms aids prediction of species resilience to climate change.

Purpose of the Study:

• Investigate cross-tolerance mechanisms between chronic warming and hypoxia in an aquatic invertebrate.
• Identify how warm acclimation influences responses to hypoxia.
• Determine the role of gene expression in cross-tolerance.

Main Methods:

• Acclimated an aquatic invertebrate to warm and cold conditions.
• Exposed both groups to hypoxia.
• Analyzed performance and gene expression changes.

Main Results:

• Warm acclimation improved hypoxic performance via hypometabolism.
• Hundreds of genes involved in hypoxia response showed altered expression ('frontloading').
• Pre-activated genes in warm-acclimated individuals reduced the need for inducible responses to hypoxia.

Conclusions:

• Transcriptional frontloading contributes to cross-tolerance between warming and hypoxia.
• Increased constitutive gene expression enhances organismal fitness under multiple stressors.
• This mechanism may promote resilience in aquatic ecosystems facing climate change and anthropogenic threats.