Variable heat shock response in Antarctic biofouling serpulid worms

Area of Science:

• Marine Biology
• Ecology
• Molecular Biology

Background:

• The classical heat shock response (HSR), characterized by hsp70 up-regulation, is often absent in Antarctic marine species.
• While Antarctic fish exhibit a specific mutation causing constitutive hsp70 expression, the HSR in Antarctic marine invertebrates remains less understood.
• Evolutionary adaptation to sub-zero temperatures may have led to generalized alterations in the HSR of these invertebrates.

Purpose of the Study:

• To investigate the heat shock response (HSR) in two Antarctic spirorbid polychaete species, Romanchella perrieri and Protolaeospira stalagmia.
• To determine if prolonged exposure to warming affects HSR induction in these species.
• To explore the species-specific nature of HSR evolution in Antarctic marine invertebrates.

Main Methods:

• In situ warming of settlement panels (+1°C and +2°C above ambient) for 18 months.
• Acute and chronic temperature elevation trials to test HSR in R. perrieri.
• Transcriptome analysis of HSP genes in P. stalagmia exposed to chronic warming.

Main Results:

• The classic HSR was not induced in R. perrieri during acute thermal challenges (2h at 15°C).
• Significant down-regulation of hsp90 was observed in R. perrieri during chronic warming (4°C for 30 days).
• Transcriptome analysis revealed up-regulation of HSP70 and HSP90 family members in P. stalagmia after 18 months of in situ warming.

Conclusions:

• Antarctic marine invertebrates display complex and variable HSRs to warming.
• The HSR in Antarctic marine species has evolved in a species-specific manner in response to long-term cold adaptation.
• Further research is needed to fully understand the HSR mechanisms in diverse Antarctic marine invertebrates.