Closely related plants show species use different methods to adapt to extreme environments, study finds

Scientists have discovered that different populations of a plant species closely related to many globally important crops use very different strategies to adapt to environmental changes, giving experts new options for designing crops to better survive climate change and address future food security.

It is often assumed that populations of the same species use the same processes to adapt to common stressors, but experts at the University of Nottingham have discovered that this is not always the case. Instead, they reveal a surprising degree of “evolutionary flexibility”.

In a new study, published in the Proceedings of the National Academy of SciencesProfessor Levi Yant from the School of Life Sciences has discovered that neighbouring ‘sister’ populations of a previously unstudied Brassica species adapt very differently to a coastal habitat. In this case, very high salinity levels, which pose an increasing threat due to climate change.

The species studied, Brassica fruticulosa, is a close relative of cabbage, broccoli, cauliflower, rapeseed and radish.

Studying wild relatives of these important crops can reveal “natural solutions” that evolution has already found. Scientists can then use this information to “future-proof” important crops around the world so they can adapt to environmental stressors, such as climate change.

To carry out this research, the team of researchers exhaustively studied all the Brassica species in the northern region of Spain and identified a single species that had exceptional populations adapted to high salinity, while other populations of the same species were not. The plants in this region naturally evolved towards the very salty Mediterranean coasts of Spain.

They then grew all the populations of Brassica fruticulosa in the lab and, using genomics, physiology and molecular biology, determined which different populations were adapted to the same stressor, in this case high salinity, in different ways.

The different adaptation strategies to high salinity, each with different genetic and mechanistic underpinnings, have been very surprising.

Professor Yant said: “People generally expect that closely related populations of a given species will adapt in the same way to the same environmental stressor due to genetic or physiological constraints. However, this has not been commonly tested due to practical limitations. Here, my collaborator, Dr Silvia Busoms, decided to look at many populations, not just a few.”

“In our new study, we show that, even at the level of neighboring populations, contrasting adaptive strategies control adaptive responses to high coastal salinity in Brassica fruticulosa. This indicates multiple options for designing a crucial adaptation for agriculture: soil salinization.

“These results will be of interest not only to those studying fundamental adaptation mechanisms, but also the enhancement of resilience in Brassica species.”