The wood pink plant (Dianthus sylvestris) is a widespread perennial in the Alps, usually inhabiting altitudes between 800 and 2,400 meters. A recent study published in Science identified adaptive cold and warm alleles that help adjust the flowering time of the plants to reflect conditions at the altitude of their habitat. As melting glaciers alter living conditions for these plants, these alleles may allow the perennials to adapt to warming temperatures.
Led by Simone Fior, a researcher at the Institute of Integrative Biology at ETH Zurich, Switzerland, the study examines three wood pink populations from valley regions and three from mountain areas in Valais, the Swiss canton that contains the largest number of glaciers in the country. The plants from these two regions differ in their flowering time. In lower elevations with an earlier snowmelt, the wood pinks have a longer growing season and tend to flower in May. The plants located at higher altitudes will blossom immediately after the snow melts later in the season to take advantage of the shorter summer.
This behavior is controlled by a specific gene called DsCEN/2 that the researchers identified in alpine wood pinks. Hirzi Luqman, a postdoctoral fellow in population genetics at Cambridge University and a co-author of the article, shared more about the CEN gene family during an interview with GlacierHub: “CEN is a key regulator of flowering time in many plants. Different plant species will typically carry different homologs and variants (alleles) of this gene, conforming to each species’ unique ecology, genetic architecture and ancestry.”
The gene’s two variants, also called alleles, are concentrated in the wood pink populations at different elevations. The wood pinks growing in warmer valley regions possess the “warm” allele, while the flowers in colder, higher altitude regions often have the “cold” allele. The warm variant associated with the later flowering of the plant leaves more time for plant growth, allowing the wood pinks to build up more biomass before flowering to produce seeds. In comparison, the cold variant shortens the plant growth period and promotes flowering immediately after snowmelt, ensuring that the seeds mature before winter—an adaptation to the shorter frost-free period in this location.
Ancestral alleles may be crucial to supporting the survival of plant species like the wood pinks, shedding light on the potential for future adaptation to today’s changing climate.
Researchers found that both alleles have ancient origins and were present in the earlier species from which the wood pink developed. By investigating genes from related species in the evolution process, the research team discovered the presence of the alleles even in very distantly related species. The gene variant did not arise from any form of mutation in the wood pink itself, but rather in other species of the Dianthus genus. A number of different species developed within the genus around 1 to 3 million years ago, during a time when the Earth’s climate was also alternating between glacial and interglacial periods.
The two alleles emerged as a means to help the wood pinks adapt to the constantly changing climate. The plants that held the appropriate “warm” or “cold” allele for their habitat conditions maintained a competitive advantage over others in the shifting climate, and these genes then became common traits passed down through plant reproduction processes.
These ancestral alleles may be crucial to supporting the survival of plant species like the wood pinks, shedding light on the potential for future adaptation to today’s changing climate. Dorothy M. Peteet, a senior research scientist at NASA Goddard Institute for Space Studies and paleoclimatologist at Lamont-Doherty Earth Observatory, which is part of the Columbia Climate School, told GlacierHub that “plant adaptive capabilities to climate are sometimes remarkable, probably because they have survived through previous cycles of climate change.”
However, rising temperatures and the consequential changes, such as the melting of alpine glaciers, are all contributing to the restructuring of mountain ecosystems. The loss of glaciers will lead to a shift in high-altitude ecosystems from a cold, specialized habitat to warmer, drier conditions. This threatens the loss of plant biodiversity and potential extinction of many species as they are unable to adapt to the warming climate. “Today, we are facing such anthropogenic challenges for plants that we need to prioritize our focus on diminishing these challenges and protecting the natural habitats that we have,” said Peteet.
Adaptive alleles offer a positive outlook for plant species in the face of climate change. Luqman shared with GlacierHub that “certain species, like the wood pink, may fare better than others because within their genome exists pre-adapted alleles that facilitate survival under a broad range of climates.” Since CEN is a key regulatory gene in many plant species, “it is possible and potentially very likely that climate adaptation via shifts in flowering time, as mediated by alleles, occurs in different plant species,” he said.
As the changing climate far outpaces the rate of plant adaptation, Luqman said that “most plant and animal species will need to rely on pre-existing genetic variation to successfully adapt.” This study highlights the significance of genetic variants passed down through generations and the crucial role they may play for the persistence of plant species in the future.
