Redaction: CREAF / CSIC / IICG-URJC / UGR / US / Grupo Tragsa
Image: Artist Emma Vidal for Moisés Expósito‑Alonso
A novel study shows that similar starting populations of plants can evolve very rapidly in response to climate change. Although evolution tends to follow partially predictable patterns under similar climatic conditions—even when these are stressful—plants exhibit distinct adaptive dynamics under climatic conditions different from their original environment.
Published in Science and involving researchers from eight Spanish institutions, including CREAF, CSIC, IICG-URJC, UGR, US, and Grupo Tragsa, the study is based on the analysis and monitoring of the evolution in response to climate change of 70,000 individuals of different genetic variants of Arabidopsis plants (pictured) sown in 30 locations around the world.
The work, carried out by an international consortium led by Moisés Expósito-Alonso of the University of California, Berkeley, along with the other two project coordinators, François Vasseur (Centre d’Ecologie Fonctionnelle et Evolutive, CNRS) and J.F. Niek Scheepens (Goethe University Frankfurt), consisted of an ambitious experiment in which 360 small plots of Arabidopsis were simultaneously sown and monitored for five years in locations with diverse climates, from alpine to desert. The experiment has allowed researchers to identify genetic variants associated with successful adaptation to different environmental contexts, as well as the conditions under which the evolutionary capacity of populations is overwhelmed by climatic pressure, leading to their extinction.
For decades, ever since scientists recognized the potential environmental damage from climate change, they have wondered whether plants can evolve quickly enough to adapt to a rapidly warming planet.
Research aimed at understanding the rapid responses of species is, ironically, progressing slowly, as it typically relies on one-off experiments conducted by isolated research groups. This is not the case with the recent work published in Science, which began with the creation of a network of collaborating scientists who carried out simultaneous experiments over five years in 30 locations with different climates across Western Europe, the Mediterranean, the Middle East, and North America. The study involved allowing plants to evolve without intervention, except for removing competition from other plant species that grew spontaneously.
The aim of this unique experiment was to unravel how quickly populations — a genetically diverse mix — of the wild plant Arabidopsis thaliana — an annual species in the Brassicaceae family, which also includes cauliflower and mustard — would evolve under different climatic stresses, ranging from the snowy Alps to the heat of the Negev desert, and from urban areas of Europe to subtropical Austin in the USA.
“Data on the rate of evolution, along with the genetic changes that accompany that evolution, are fundamental for creating models that help identify which plants and animals are at risk as their environments change,” says the study’s lead author, Moisés Expósito-Alonso, a researcher and professor at the University of California, Berkeley.
Plants will continue to be affected by changes in local climates, so it is essential to devise some kind of strategy to understand their real possibilities for climate adaptation, either on their own or through adaptation aids. To guarantee their survival, it is imperative to generate quantitative data that allows us to better understand rapid adaptation and make predictions, anticipate where the risks lie, where climate thresholds might be, and what aspects require attention.
The first genomic analysis of plant samples from 12 distinct plots across 30 locations—a total of 360 independent experimental units—shows that, in most cases, the plants evolved genetically to adapt to the characteristic environmental conditions of each environment. However, some experimental populations, especially those located in the most extreme hot climates, showed no signs of early evolution. Instead, they exhibited seemingly random trajectories that preceded their extinction.
The study allows researchers to see directly, and for the first time, how certain DNA variants—adaptive variants—come to dominate in specific populations as evolution occurs. But the researchers also discovered that not all populations adapted effectively enough to survive, especially in the hottest environments, which are perhaps the most representative of future climates. This reveals that, although rapid adaptation to climate change is possible, extreme heat reduces populations to very small sizes, where the available adaptive capacity is very low, and extinction is precipitated.
A large consortium, the Genomics of Rapid Evolution to Novel Environment (GrENE net) network, comprising around 75 scientists from the US, Spain, Norway, Germany, Switzerland, Canada, Greece, Estonia, Poland, the Netherlands, France, and Israel, conducted the research between autumn 2017 and spring 2022.
As part of their research at Spanish institutions, the following are co-authors of the paper published in Science: Carlos Alonso Blanco and Belén Méndez de Vigo Somolinos from the National Center for Biotechnology (CNB-CSIC), Xavier Picó from the Doñana Biological Station (EBD-CSIC), Anna Traveset from the Mediterranean Institute for Advanced Studies (IMEDEA (CSIC-UIB)), Modesto Berbel Cascales and Mohamed Abdelaziz from the University of Granada (UGR), Arnald Marcer from the Centre for Ecological Research and Forestry Applications (CREAF), Ana García Muñoz from the University of Seville (US), Gema Escribano from Tragsatec and Alfredo García Fernández, José María Iriondo Alegría, Carlos Lara Romero and Martí March Salas from the Global Change Research Institute (IICG-URJC).
Researchers from the IICG-URJC participated throughout the entire process of this ambitious project; a collaborative initiative involving numerous groups and developed without specific funding. The scarcity of resources was mitigated by the excellent work of all involved. “The synchronization among so many groups from multiple countries, under a standardized, simple protocol, despite the complexity of the issue being addressed, is what makes it unique,” stated Carlos Lara, Alfredo García, Martí March, and José María Iriondo, researchers at the IICG-URJC.
Adapt or die
The goal was not only to measure the speed of evolutionary adaptation in Arabidopsis, but also to identify the allelic variants within a population that enable adaptation to a changing environment. The expectation was that the genetic diversity of the initial population would ensure that at least some plants in each plot possessed the genetic makeup that a resilient population needs to adapt to new conditions.
To capture changes in genetic composition, flowers were sampled each spring, and the genomes of all surviving plants in each plot were sequenced together. From the sequences of more than 70,000 surviving specimens in over 2,500 samples, the frequencies of millions of single nucleotide polymorphisms (SNPs) in each population were estimated, allowing researchers to identify which variants increased or decreased over time. These gene variants differed in different climates but were similar in similar climates, demonstrating the repeatability of these adaptations.
The indication that this was an adaptation by natural selection—that is, the survival of the plants best adapted to the new environment—came from the fact that several of the 12 plots in each location showed similar changes in gene frequency. Another indication was that several of the 12 plots in two locations with similar environments—for example, the dry scrublands of Spain and Greece—showed similar changes. This was observed in 24 of the 30 locations. Among the most affected genes were those that sense heat stress and others that control when plants flower.
Although some genetic changes were theoretically expected in such an experiment, with abundant diversity and severe climatic exposure, it was surprising to discover that the rate at which allele frequencies changed was greater than most biologists would have predicted.
Furthermore, not all plots showed evolutionary adaptation: some eventually became extinct. Because the team sampled each of the 360 plots annually for several years, they were able to document that those that showed random genetic changes or no genetic changes in the early years of the experiment eventually disappeared.
For a population to survive long-term under climate change, it will most likely have to undergo a process of natural selection. This means that unless there is an evolutionary rescue—that is, genotypes with greater fitness that spread more widely and increase their allele frequencies—the population will not be able to maintain its size after five years, at least in warm environments.
An additional finding of the study is that Arabidopsis plants from warm regions already show a lag in adaptation; that is, they thrive better in environments approximately 1.5°C cooler than their place of origin. This suggests that the cumulative global warming to date has left these populations slightly mismatched with their current climates.
Knowledge-based inferences
While each species might require its own long-term experiment to understand its genetic vulnerabilities, the knowledge gained about Arabidopsis allows us to make some inferences about which populations will survive in each location. In other words, these types of models, calibrated on a model species and with a deep understanding of the pace of evolution and the magnitude of ecological disruption due to adaptation and climate change, could potentially help hundreds or thousands of species.
The research group continues to conduct evolutionary analyses and experiments, some of them with plants other than Arabidopsis. One of their long-term ambitions is to capture rapid evolution in natural populations by directly observing year-to-year genetic variation in wild plants that naturally experience climate fluctuations and global warming. This would allow them to understand, for the first time, the constant pace of evolution, which remains hidden within healthy and seemingly stable ecosystems. It might even be possible to record sudden genetic changes triggered by drought or forest fires, enabling the design of measures to protect species or mitigate their effects.
In this regard, the four researchers from the IICG-URJC are actively participating in the AdapTest project, led by Javier Morente (Goethe University Frankfurt), within which experiments have recently been carried out at the Organism Culture Laboratory (CULTIVE, IICG-URJC). Seed germination continues, thus maintaining the Spanish collaboration in GrENE net.
REFERENCE:
Wu et al., Rapid adaptation and extinction in synchronized outdoor evolution experiments of Arabidopsis. Science 391, eadz0777(2026). https://doi.org/10.1126/science.adz0777