Transcriptomics at the thermal limits of an urban introduced lizard

Area of Science:

• Environmental physiology
• Molecular biology
• Ecology

Background:

• Physiological plasticity aids animals in coping with environmental stressors.
• Temperature stress is a significant threat, particularly to ectotherms.
• Rapid thermal stress exposure, common in nature, can shift gene expression.

Purpose of the Study:

• To assess gene expression plasticity in response to brief extreme thermal stress in the common wall lizard (Podarcis muralis).
• To compare transcriptomic responses to heat and cold stress across different tissues.
• To evaluate the potential of gene expression plasticity in facilitating species' range expansion.

Main Methods:

• RNA-sequencing was used to compare transcriptomes of lizards exposed to critical thermal maximum (CTmax), critical thermal minimum (CTmin), or control conditions.
• Lizards underwent rapid ramping to thermal extremes followed by recovery.
• Heart, liver, and large intestine tissues were analyzed.

Main Results:

• Heat stress induced a significantly stronger gene expression response than cold stress across all tissues.
• Systemic upregulation of heat shock proteins and stress response pathways was observed following heat exposure.
• Heat exposure also altered transcription, translation, and metabolic processes in a tissue-specific manner.

Conclusions:

• Gene expression plasticity in response to thermal stress may facilitate range expansion in the common wall lizard.
• Brief heat exposure elicits a robust, systemic gene expression response.
• Further research is needed to understand transcriptomic responses to natural temperature fluctuations.