Parallel evolution of salinity tolerance in Arabidopsis thaliana accessions from Cape Verde Islands

Soil salinization poses a notable threat to agriculture. The Cape Verde Islands are located 600 km off the coast of Africa and are characterized by arid environments and high-salinity soils. Here, we find that Arabidopsis thaliana plants native to these islands accumulate glucuronyl-mannose that protects them from salt stress. We map the ability to produce this metabolite to an α glycosidase family 38 gene that we named GH38cv. Plants carrying mutant alleles of GH38cv do not present defects on growth, fitness, or biotic resistance under standard laboratory conditions but show better germination rates, longer roots, better hydric status, and higher fitness than nonmutated plants when exposed to salt stress. Notably, deleterious mutations in GH38cv have evolved independently on two separate islands within the Cape Verde archipelago, illustrating an example of parallel evolution for salt tolerance in this environment. Our findings reveal a knowledge-driven method to develop salt-resilient crops, which could be attractive to both conventional and organic agriculture.