Format: ORAL

P. Raimondeau1,2, S. Ksouda1, W. Marande3, A-L. Fuchs1, H. Gryta1, A. Puyoou1, J. Dupin1, P-O. Cheptou4, S. Vautrin3, S. Valire3, S. Manzi1, D. Baali-Cherif5, J. Chave1, P-A. Christin6, G. Besnard1*

1 CNRS, Université Paul Sabatier, IRD, UMR 5174 EDB (Laboratoire Évolution & Diversité Biologique), 118 Route de Narbonne, 31062 Toulouse, France 2 Yale Institute of Biospheric Studies, New Haven, CT 06520, USA 3 INRAE/CNRGV, US 1426, GeT-PlaGe, Genotoul, Castanet-Tolosan, France 4 CEFE (Centre d’Ecologie Fonctionnelle et Evolutive), UMR 5175, CNRS, Université de Montpellier, Université Paul Valéry, EPHE, IRD, 34293 Montpellier, France 5 Laboratoire de Recherche sur les Zones Arides, USTHB/ENSA, Alger, Algeria 6 Ecology and Evolutionary Biology, School of Biosciences, University of Sheffield, Sheffield S10 2TN, UK

Self-incompatibility (SI) evolved independently multiple times and prevent self-fertilization in hermaphrodite angiosperms. Several groups of Oleaceae such as jasmines exhibit distylous flowers, with two compatibility groups each associated to a specific floral morph. Other Oleaceae species, in the olive tribe, harbor two compatibility groups without associated morphological variation. The genetic basis of both homomorphic and dimorphic SI systems of Oleaceae are unknown. By comparing genomic sequences of three olive subspecies (Olea europaea) belonging to the two compatibility groups, we first locate the genetic determinism for self-incompatibility within a 700-kb hemizygous region present only in one of the two types. We then demonstrate that a homologous hemizygous region is also involved in controlling distyly in jasmine. Phylogenetic analyses support a common origin of both systems following a segmental genomic duplication in their ancestor. We postulate that self-incompatibility and dityly imply two genes in the hemizygous region that are involved in gibberellin and brassinosteroid regulation, underpinning the diversity of incompatibility systems in the group.