TY - JOUR TI - Asymmetrical diversification of the receptor-ligand interaction controlling self-incompatibility in Arabidopsis AU - Chantreau, Maxime AU - Poux, CĂ©line AU - Lensink, Marc F AU - Brysbaert, Guillaume AU - Vekemans, Xavier AU - Castric, Vincent A2 - McCormick, Sheila A2 - Hardtke, Christian S A2 - McCormick, Sheila A2 - Barton, Nick H VL - 8 PY - 2019 DA - 2019/11/25 SP - e50253 C1 - eLife 2019;8:e50253 DO - 10.7554/eLife.50253 UR - https://doi.org/10.7554/eLife.50253 AB - How two-component genetic systems accumulate evolutionary novelty and diversify in the course of evolution is a fundamental problem in evolutionary systems biology. In the Brassicaceae, self-incompatibility (SI) is a spectacular example of a diversified allelic series in which numerous highly diverged receptor-ligand combinations are segregating in natural populations. However, the evolutionary mechanisms by which new SI specificities arise have remained elusive. Using in planta ancestral protein reconstruction, we demonstrate that two allelic variants segregating as distinct receptor-ligand combinations diverged through an asymmetrical process whereby one variant has retained the same recognition specificity as their (now extinct) putative ancestor, while the other has functionally diverged and now represents a novel specificity no longer recognized by the ancestor. Examination of the structural determinants of the shift in binding specificity suggests that qualitative rather than quantitative changes of the interaction are an important source of evolutionary novelty in this highly diversified receptor-ligand system. KW - self-incompatibility KW - ancestral protein resurrection KW - evolutionary novelty KW - receptor-ligand interaction JF - eLife SN - 2050-084X PB - eLife Sciences Publications, Ltd ER -