Journal Article

Evidence for the long-term maintenance of a rare self-incompatibility system in Oleaceae

Dommée, Bertrand, Évolution, Écologie et Paléontologie (Evo-Eco-Paleo) - UMR 8198 (Evo-Eco-Paléo (EEP)) ; Université de Lille-Centre National de la Recherche Scientifique (CNRS), Saumitou-Laprade, Pierre, Billiard, Sylvain, Lepart, Jacques, Vernet, Philippe, Lepercq, Pierre, Centre d’Ecologie Fonctionnelle et Evolutive (CEFE) ; Université Paul-Valéry - Montpellier 3 (UPVM)-Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-École Pratique des Hautes Études (EPHE) ; Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [Occitanie])-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Bourceaux, Angélique

2016

Overview

A rare homomorphic diallelic self-incompatibility (DSI) system discovered in Phillyrea angustifolia (family Oleaceae, subtribe Oleinae) can promote the transition from hermaphroditism to androdioecy. If widespread and stable in Oleaceae, DSI may explain the exceptionally high rate of androdioecious species reported in this plant family. Here, we set out to determine whether DSI occurs in another Oleaceae lineage. We tested for DSI in subtribe Fraxininae, a lineage that diverged from subtribe Oleinae c. 40 million yr ago. We explored the compatibility relationships in Fraxinus ornus using 81 hermaphrodites and 25 males from one natural stand and two naturalized populations using intra- and interspecific stigma tests performed on F. ornus and P. angustifolia testers. We uncovered a DSI system with hermaphrodites belonging to one of two self-incompatibility (SI) groups and males compatible with both groups, making for a truly androdioecious reproductive system. The two human-founded populations contained only one of the two SI groups. Our results provide evidence for the evolutionary persistence of DSI. We discuss how its stability over time may have affected transitions to other sexual systems, such as dioecy.

• Publisher: Wiley,CCSD,New Phytologist Trust,Wiley Subscription Services, Inc
• Subject: androdioecy / Biological Evolution / cryptic dioecy / diallelic self‐incompatibility system / dioecy / Flowers - genetics / Flowers - physiology / Fraxinus - genetics / Fraxinus - physiology / Fraxinus ornus / Genetics / hermaphroditism / Life Sciences / males / naturalized populations / Oleaceae - genetics / Oleaceae - physiology / Phillyrea angustifolia / plant mating systems / Populations and Evolution / Reproduction / Reproductive system / Self-Incompatibility in Flowering Plants / stigma / transgeneric conservation of SI functionality