Parallel evolution to salt stress found in Cabo Verde Plants

Soil salinization is a persistent threat to agriculture, particularly in island and coastal regions where arid conditions and salt-rich soils are common. In such environments, native plants must evolve mechanisms to survive. One example is the Cabo Verdean population of Arabidopsis thaliana. A new international study, published in Science Advances and led by José María Jiménez-Gómez of CBGP (UPM-INIA/CSIC), in collaboration with Gilles Clément and Oliver Loudet of IJPB (INRAE, France), offers new insights into how plants adapt to extreme conditions through evolution.

Parallel evolution

In the study, researchers examined Arabidopsis thaliana plants from the African archipelago of Cabo Verde and discovered they produce a unique substance not found in populations elsewhere. This compound, a disaccharide made of glucuronic acid and mannose, is a metabolite involved in plant metabolism. Tracing its origin, the team identified the gene responsible for its production. Remarkably, they found that this gene had undergone independent mutations in populations on two separate islands, pointing to a case of parallel evolution likely driven by positive natural selection.

Species that manage to thrive in harsh environments often evolve specific adaptations to local challenges, such as the high soil salinity found in Cabo Verde. In some cases, similar adaptations emerge independently in distant populations, a phenomenon known as parallel evolution. This repeated emergence of similar traits is seen as strong evidence of natural selection at work, since such patterns are unlikely to occur by chance alone.

Salt-resistant crops

Surprisingly, the researchers found that the genetic mutation and resulting metabolite production had no impact on plant growth under normal conditions or on their defense against pathogens. However, under extreme salinity, plants producing the metabolite showed clear advantages: higher germination rates, longer roots, better water retention, and increased seed production compared to plants lacking the mutation and the metabolite.

The results establish a basis for new possibilities for harnessing the synthesis of this metabolite or applying gene editing in biofortification or bioprotection strategies. In particular, it could represent an approach based on natural methods for developing crops, both conventional and organic, with greater resistance to salinity in extreme environmental conditions.