Study reveals how algae adapt to cold temperatures in Antarctica

A Chinese study has revealed how a type of algae adapt to cold temperatures in Antarctica with special proteins and enzymes.

Chlorella is a genus of unicellular green algae distributed all over the world. In the study, researchers from the Institute of Hydrobiology under the Chinese Academy of Sciences and other Chinese research institutes focused on NJ-7, a chlorella strain found in Antarctica, and UTEX259, a strain from temperate regions.

During the evolution process, NJ-7 diverged from UTEX259 of the same species about 2.6 million years ago. The two chlorella strains have highly similar genetic information.

However, NJ-7 can grow in temperatures of 4 degrees Celsius, while UTEX259 cannot. NJ-7 also has much better antifreeze capability, tolerating temperatures of 20 degrees Celsius below zero.

According to the research paper published in Molecular Biology and Evolution, the secret behind NJ-7's growth in Antarctica is that NJ-7 had systematic increases of some key enzymes and LEA proteins, proteins that protect other proteins from stresses associated with low temperatures.

The researchers said NJ-7 showed significantly higher quantities and activity of the proteins and enzymes. Furthermore, the proteins and enzymes were not upregulated in response to cold stress.

Xu Xudong, corresponding author of the research, said the study reveals the early stage adaptation of algae to Antarctica in which enzymes maintained relatively high activities in cold environments prior to the cold adaptation of enzymes.

The study will provide insights into future studies on how microbes, animals and plants adapted to the low temperatures in Antarctica.