Antarctic moss proves cold weather isn’t just for penguins

New research shows Antarctic moss can grow and survive in freezing, harsh conditions by using special fats that keep its cells flexible, helping it cope with extreme cold and other stresses.

Mosses, which often go unnoticed in gardens and forests, have demonstrated an outstanding ability to adapt to extreme environments. Among them, Antarctic mosses are particularly interesting due to their resilience in one of the most challenging climates on Earth. Despite the freezing temperatures, prolonged drought, and intense ultraviolet radiation, these plants not only survive but also exhibit active growth during a brief summer season. Now, new research published in AoB PLANTS, shows that some Antarctic mosses adapt to these conditions by increasing the expression of genes related to lipid metabolism and the accumulation of unsaturated fatty acids.

In this new study, the research team from Niigata University in Japan, focused on Bryum pseudotriquetrum, one of the more common mosses found in Antarctica. By employing transcriptome analyses, they explored how this species adapts to its challenging surroundings, particularly in comparison to controlled artificial conditions at 15°C.

The research generated 88,205 contigs through de novo assembly, which represent the diverse array of genes expressed by this moss species. The analysis unveiled that under natural Antarctic field conditions 1,377 genes were upregulated, while 435 were downregulated when compared to those grown in more temperate, artificially controlled settings. But what does this mean for the moss’s survival? The upregulated genes included several related to lipid metabolism and the formation of oil bodies, two critical components that play a vital role in plants’ ability to cope with stress.

Lipid metabolism is crucial for plants, especially in extreme environments where maintaining cellular integrity is essential. The study found that the expression levels of these lipid-related genes increased significantly in response to various artificial stress treatments, including low temperatures, salt exposure, and osmotic stress. This suggests that Bryum pseudotriquetrum has evolved mechanisms to change its lipid profiles in response to environmental challenges.

Interestingly, the researchers observed that mosses grown in Antarctic conditions contained elevated levels of fatty acids, particularly α-linolenic acid, linolenic acid, and arachidonic acid and a higher proportion of unsaturated fatty acids. These fatty acids play a key role in maintaining membrane fluidity, and thus support cellular function in cold environments where membranes might otherwise become rigid.

In the present study, RNA-seq analysis was carried out in the common moss Bryum pseudotriquetrum and genes related to lipid metabolism and oil body formation were found to be highly expressed in field samples. In plant cells, lipid accumulation and changes in fatty acid composition are important mechanisms for acquiring environmental stress tolerance. Thus, these genes may be involved in multiple stress tolerance in Bryum pseudotriquetrum growing in Antarctica.

This study marks a significant advance in our understanding of how some plants respond to the extreme conditions of their native habitats. By providing the first gene expression profiles for mosses grown directly under Antarctic field conditions, it highlights the role of lipid metabolism and fatty acid composition in stress tolerance. The results also highlight the importance of in situ studies for understanding the mechanisms of plant resilience in stressed environments.

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Otani N., Kitamura H., Kudoh S., Imura S. and Nakano M. (2024) “Transcriptome analysis of the common moss Bryum pseudotriquetrum grown under Antarctic field condition” AoB PLANTS. Available at: https://doi.org/10.1093/aobpla/plae043

Cover image by HermannSchachner – Own work, CC0, Link