Сибирский федеральный университет

Coast redwood trees grow in some warm and humid regions of Europe, and thanks to global warming, the number of such areas is constantly increasing. However, coast redwood periodically suffers from freezing temperatures, and the aim of this project, funded by the Federal Ministry of Food and Agriculture of Germany (BMEL), is to select frost-resistant tree clones and study the genetic mechanisms of their resistance.

These trees belong to the unique genus Sequoia, consisting of the sole living species Sequoia sempervirens, formed about 300 million years ago and flourished during the age of dinosaurs. As gigantic as the ancient reptiles, but, unlike them, survived and preserved almost unchanged to our time, these trees are living fossils that once occupied vast territories. Coast redwood trees hold several biological records. They are one of the largest (weighing over 1000 tons), tallest (over 100 m), and most long-lived (over 2000 years) organisms.

According to the authors of the study, coast wood trees grow rapidly, have high-quality wood and unique adaptive characteristics. They have a thick bark that reliably protects them from fires, as well as a high capacity for vegetative growth, i.e. new trees grow from the roots and stumps of felled and dead ones. Moreover, coast redwood is capable of clonal reproduction, which makes it easy to multiply genotypes and clones of coast redwood valuable for the forestry industry. The needles of a “living fossil” are capable of condensing moisture in the morning and at night foggy hours and even absorb it from the air, which helps coast wood survive in drought. This tree might be called ideal for the forest industry if it were not so warmth and moisture-loving! These features have hindered, until today, the widespread distribution of plantations outside the natural habitat of the tree, i.e. the Pacific coast of the United States.

“Coast redwood is the most amazing tree on earth. If you have ever visited untouched ancient forests, located in a narrow strip along the northern coast of California, where these fabulous giants grow, you will never forget the magical feeling of what you saw. Having moved to Germany in 2012, I was surprised to find that coast redwood grows here not only in arboretums. Why does this tree feel comfortable in some regions of Germany and grows even outdoors? After all, winters in this country are quite cold. So the idea arose to study the genetic mechanisms of coast redwood adaptation to more severe habitat conditions. BMEL supported the project, as it is interested in plantation cultivation of coast redwood in Western Europe for the needs of the forest industry,” informed Konstantin Krutovskii.

To test the adaptability of coast redwood to more severe habitat conditions than those in California, scientists experimented on growing trees in laboratory climate chambers that simulate temperature, light, and humidity in winter in some parts of Germany. The experiment showed that it is possible to select special frost-resistant genotypes of coast redwood, promising for cultivation in Europe.

“After sequencing the total RNA, we studied the differential expression, i.e. transformation of hereditary information into RNA and then protein, of genes of different coast redwood clones under the influence of low temperatures, using automatic programmable climatic chambers in which temperature, light, and humidity can be controlled. It was an imitation of the conditions of winter Germany,” said the scientist.

The researchers have managed to cope with the most important task of obtaining a coast redwood reference transcriptome, i.e. its assembly from hundreds of millions of sequenced RNA fragments and functional annotation.

“Considering the size and complexity of the transcriptome of the hexaploid coast redwood, the genome of which has increased sixfold in the process of evolution, this is an immense bioinformatics task that can be solved only with the help of a supercomputer. In SibFU’s High-Performance Computing Center, supervised by Dmitry Kuzmin, head of High-Performance Computing Department, we were able to collect a transcriptome of more than 600 thousand unique transcripts representing a genome-wide analysis of the expression of several hundred thousand genes of coast redwood, and thus contributed to international research,” explained Vadim Sharov, co-author of the publication.

According to experts, the experiment showed that thanks to global warming, more and more regions in Europe and even in Russia may become suitable for growing coast redwood trees, especially in case of successful selection of frost-resistant clones.

“I venture to make a small scientific prediction. If global warming proceeds as predicted by modern climatologists and forestry experts, we may one day see relict coast redwood trees even in Siberia. Based on the data we have, geneticists may well select the appropriate coast redwood clones, which will be able to successfully survive in the softening Siberian winter and hot summer,” summed up Konstantin Krutovskii.