Plant community productivity often increases with diversity, but identifying the underlying mechanisms is challenging. This study uses a gene-centered approach with *Arabidopsis thaliana* genotypes to investigate this phenomenon. Two genetic mapping methods revealed that allelic differences at the *AtSUC8* locus (encoding a proton-sucrose symporter) are strongly associated with mixture overyielding. Genetic variation in *AtSUC8* influences protein activity and root growth responses to substrate pH. This suggests that evolutionary divergence along an edaphic gradient led to niche complementarity driving overyielding. Identifying such genes can link ecological processes to evolutionary drivers and facilitate the development of high-performance crop mixtures.

Samuel E. Wuest, Lukas Schulz, Surbhi Rana, Julia Frommelt, Merten Ehmig, Nuno D. Pires, Ueli Grossniklaus, Christian S. Hardtke, Ulrich Z. Hammes, Bernhard Schmid, Pascal A. Niklaus