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De Cauwer I, Vernet P, Billiard S, Godé C, Bourceaux A, Ponitzki C, Saumitou-Laprade P. Widespread coexistence of self-compatible and self-incompatible phenotypes in a diallelic self-incompatibility system in Ligustrum vulgare (Oleaceae). Heredity (Edinb) 2021; 127:384-392. [PMID: 34482370 PMCID: PMC8479060 DOI: 10.1038/s41437-021-00463-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 07/26/2021] [Accepted: 07/26/2021] [Indexed: 02/07/2023] Open
Abstract
The breakdown of self-incompatibility (SI) in angiosperms is one of the most commonly observed evolutionary transitions. While multiple examples of SI breakdown have been documented in natural populations, there is strikingly little evidence of stable within-population polymorphism with both inbreeding (self-compatible) and outcrossing (self-incompatible) individuals. This absence of breeding system polymorphism corroborates theoretical expectations that predict that in/outbreeding polymorphism is possible only under very restricted conditions. However, theory also predicts that a diallelic sporophytic SI system should facilitate the maintenance of such polymorphism. We tested this prediction by studying the breeding system of Ligustrum vulgare L., an insect-pollinated hermaphroditic species of the Oleaceae family. Using stigma tests with controlled pollination and paternity assignment of open-pollinated progenies, we confirmed the existence of two self-incompatibility groups in this species. We also demonstrated the occurrence of self-compatible individuals in different populations of Western Europe arising from a mutation affecting the functioning of the pollen component of SI. Our results show that the observed low frequency of self-compatible individuals in natural populations is compatible with theoretical predictions only if inbreeding depression is very high.
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Affiliation(s)
- Isabelle De Cauwer
- grid.503422.20000 0001 2242 6780Univ. Lille, UMR 8198 – Evo-Eco-Paleo, F-59000 Lille, France ,grid.4444.00000 0001 2112 9282CNRS, UMR 8198, F-59000 Lille, France
| | - Philippe Vernet
- grid.503422.20000 0001 2242 6780Univ. Lille, UMR 8198 – Evo-Eco-Paleo, F-59000 Lille, France ,grid.4444.00000 0001 2112 9282CNRS, UMR 8198, F-59000 Lille, France
| | - Sylvain Billiard
- grid.503422.20000 0001 2242 6780Univ. Lille, UMR 8198 – Evo-Eco-Paleo, F-59000 Lille, France ,grid.4444.00000 0001 2112 9282CNRS, UMR 8198, F-59000 Lille, France
| | - Cécile Godé
- grid.503422.20000 0001 2242 6780Univ. Lille, UMR 8198 – Evo-Eco-Paleo, F-59000 Lille, France ,grid.4444.00000 0001 2112 9282CNRS, UMR 8198, F-59000 Lille, France
| | - Angélique Bourceaux
- grid.503422.20000 0001 2242 6780Univ. Lille, UMR 8198 – Evo-Eco-Paleo, F-59000 Lille, France ,grid.4444.00000 0001 2112 9282CNRS, UMR 8198, F-59000 Lille, France
| | - Chloé Ponitzki
- grid.503422.20000 0001 2242 6780Univ. Lille, UMR 8198 – Evo-Eco-Paleo, F-59000 Lille, France ,grid.4444.00000 0001 2112 9282CNRS, UMR 8198, F-59000 Lille, France
| | - Pierre Saumitou-Laprade
- grid.503422.20000 0001 2242 6780Univ. Lille, UMR 8198 – Evo-Eco-Paleo, F-59000 Lille, France ,grid.4444.00000 0001 2112 9282CNRS, UMR 8198, F-59000 Lille, France
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2
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Kučera J, Svitok M, Gbúrová Štubňová E, Mártonfiová L, Lafon Placette C, Slovák M. Eunuchs or Females? Causes and Consequences of Gynodioecy on Morphology, Ploidy, and Ecology of Stellaria graminea L. (Caryophyllaceae). FRONTIERS IN PLANT SCIENCE 2021; 12:589093. [PMID: 33912199 PMCID: PMC8072285 DOI: 10.3389/fpls.2021.589093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Accepted: 03/22/2021] [Indexed: 06/12/2023]
Abstract
Plant speciation results from intricate processes such as polyploidization, reproductive strategy shifts and adaptation. These evolutionary processes often co-occur, blurring their respective contributions and interactions in the speciation continuum. Here, relying on a large-scale study, we tested whether gynodioecy triggers the divergent evolution of flower morphology and genome between sexes, and contributes to the establishment of polyploids and colonization of ecological niches in Stellaria graminea. We found that gynodioecy in S. graminea leads to flower morphology divergence between females and hermaphrodites, likely due to sexual selection. Contrary to our expectations, gynodioecy occurs evenly in diploids and tetraploids, suggesting that this reproductive strategy was not involved in the establishment of polyploids. Both diploid and tetraploid females have a larger genome size than hermaphrodites, suggesting the presence of sex chromosomes. Finally, ecology differs between cytotypes and to a lesser extent between sexes, suggesting that the link between environment and presence of females is indirect and likely explained by other aspects of the species' life history. Our study shows that gynodioecy leads to the consistent evolution of sexual traits across a wide range of populations, cytotypes and environments within a given species, and this likely contributes to the phenotypic and genetic distinctiveness of the species from its sister clades.
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Affiliation(s)
- Jaromír Kučera
- Plant Science and Biodiversity Centre, Institute of Botany, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Marek Svitok
- Faculty of Ecology and Environmental Sciences, Technical University in Zvolen, Zvolen, Slovakia
- Department of Ecosystem Biology, Faculty of Science, University of South Bohemia in České Budějovice, České Budějovice, Czechia
| | - Eliška Gbúrová Štubňová
- Plant Science and Biodiversity Centre, Institute of Botany, Slovak Academy of Sciences, Bratislava, Slovakia
- Slovak National Museum, Natural History Museum, Bratislava, Slovakia
| | | | | | - Marek Slovák
- Plant Science and Biodiversity Centre, Institute of Botany, Slovak Academy of Sciences, Bratislava, Slovakia
- Department of Botany, Charles University, Prague, Czechia
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Besnard G, Cheptou P, Debbaoui M, Lafont P, Hugueny B, Dupin J, Baali‐Cherif D. Paternity tests support a diallelic self-incompatibility system in a wild olive ( Olea europaea subsp. laperrinei, Oleaceae). Ecol Evol 2020; 10:1876-1888. [PMID: 32128122 PMCID: PMC7042767 DOI: 10.1002/ece3.5993] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Revised: 12/16/2019] [Accepted: 12/20/2019] [Indexed: 01/31/2023] Open
Abstract
Self-incompatibility (SI) is the main mechanism that favors outcrossing in plants. By limiting compatible matings, SI interferes in fruit production and breeding of new cultivars. In the Oleeae tribe (Oleaceae), an unusual diallelic SI system (DSI) has been proposed for three distantly related species including the olive (Olea europaea), but empirical evidence has remained controversial for this latter. The olive domestication is a complex process with multiple origins. As a consequence, the mixing of S-alleles from two distinct taxa, the possible artificial selection of self-compatible mutants and the large phenological variation of blooming may constitute obstacles for deciphering SI in olive. Here, we investigate cross-genotype compatibilities in the Saharan wild olive (O. e. subsp. laperrinei). As this taxon was geographically isolated for thousands of years, SI should not be affected by human selection. A population of 37 mature individuals maintained in a collection was investigated. Several embryos per mother were genotyped with microsatellites in order to identify compatible fathers that contributed to fertilization. While the pollination was limited by distance inside the collection, our results strongly support the DSI hypothesis, and all individuals were assigned to two incompatibility groups (G1 and G2). No self-fertilization was observed in our conditions. In contrast, crosses between full or half siblings were frequent (ca. 45%), which is likely due to a nonrandom assortment of related trees in the collection. Finally, implications of our results for orchard management and the conservation of olive genetic resources are discussed.
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Affiliation(s)
| | - Pierre‐Olivier Cheptou
- CEFE, Univ Montpellier, CNRS, EPHE, IRD, Univ Paul Valery Montpellier 3MontpellierFrance
| | - Malik Debbaoui
- EDBUMR 5174CNRS‐IRD‐UPSUniversité Paul SabatierToulouse cedexFrance
| | - Pierre Lafont
- EDBUMR 5174CNRS‐IRD‐UPSUniversité Paul SabatierToulouse cedexFrance
| | - Bernard Hugueny
- EDBUMR 5174CNRS‐IRD‐UPSUniversité Paul SabatierToulouse cedexFrance
| | - Julia Dupin
- EDBUMR 5174CNRS‐IRD‐UPSUniversité Paul SabatierToulouse cedexFrance
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Saumitou-Laprade P, Vernet P, Vekemans X, Billiard S, Gallina S, Essalouh L, Mhaïs A, Moukhli A, El Bakkali A, Barcaccia G, Alagna F, Mariotti R, Cultrera NGM, Pandolfi S, Rossi M, Khadari B, Baldoni L. Elucidation of the genetic architecture of self-incompatibility in olive: Evolutionary consequences and perspectives for orchard management. Evol Appl 2017; 10:867-880. [PMID: 29151878 PMCID: PMC5680433 DOI: 10.1111/eva.12457] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Accepted: 01/05/2017] [Indexed: 12/15/2022] Open
Abstract
The olive (Olea europaea L.) is a typical important perennial crop species for which the genetic determination and even functionality of self‐incompatibility (SI) are still largely unresolved. It is still not known whether SI is under gametophytic or sporophytic genetic control, yet fruit production in orchards depends critically on successful ovule fertilization. We studied the genetic determination of SI in olive in light of recent discoveries in other genera of the Oleaceae family. Using intra‐ and interspecific stigma tests on 89 genotypes representative of species‐wide olive diversity and the compatibility/incompatibility reactions of progeny plants from controlled crosses, we confirmed that O. europaea shares the same homomorphic diallelic self‐incompatibility (DSI) system as the one recently identified in Phillyrea angustifolia and Fraxinus ornus. SI is sporophytic in olive. The incompatibility response differs between the two SI groups in terms of how far pollen tubes grow before growth is arrested within stigma tissues. As a consequence of this DSI system, the chance of cross‐incompatibility between pairs of varieties in an orchard is high (50%) and fruit production may be limited by the availability of compatible pollen. The discovery of the DSI system in O. europaea will undoubtedly offer opportunities to optimize fruit production.
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Affiliation(s)
- Pierre Saumitou-Laprade
- CNRSUMR 8198 Evo-Eco-Paleo Université de Lille - Sciences et Technologies Villeneuve d'Ascq France
| | - Philippe Vernet
- CNRSUMR 8198 Evo-Eco-Paleo Université de Lille - Sciences et Technologies Villeneuve d'Ascq France
| | - Xavier Vekemans
- CNRSUMR 8198 Evo-Eco-Paleo Université de Lille - Sciences et Technologies Villeneuve d'Ascq France
| | - Sylvain Billiard
- CNRSUMR 8198 Evo-Eco-Paleo Université de Lille - Sciences et Technologies Villeneuve d'Ascq France
| | - Sophie Gallina
- CNRSUMR 8198 Evo-Eco-Paleo Université de Lille - Sciences et Technologies Villeneuve d'Ascq France
| | | | - Ali Mhaïs
- Montpellier SupAgro UMR 1334 AGAP Montpellier France.,INRAUR Amélioration des Plantes Marrakech Morocco.,Laboratoire AgroBiotech L02B005 Faculté des Sciences et Techniques Guéliz University Cadi Ayyad Marrakech Morocco
| | | | - Ahmed El Bakkali
- INRAUR Amélioration des Plantes et Conservation des Ressources Phytogénétiques Meknès Morocco
| | - Gianni Barcaccia
- Laboratory of Genomics and Plant Breeding DAFNAE - University of Padova Legnaro PD Italy
| | - Fiammetta Alagna
- Research Unit for Table Grapes and Wine Growing in Mediterranean Environment CREATuriBA Italy.,CNRInstitute of Biosciences and BioresourcesPerugiaItaly
| | | | | | | | - Martina Rossi
- CNRInstitute of Biosciences and BioresourcesPerugiaItaly
| | - Bouchaïb Khadari
- Montpellier SupAgro UMR 1334 AGAP Montpellier France.,INRA/CBNMed UMR 1334 Amélioration Génétique et Adaptation des Plantes (AGAP) Montpellier France
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5
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Vernet P, Lepercq P, Billiard S, Bourceaux A, Lepart J, Dommée B, Saumitou-Laprade P. Evidence for the long-term maintenance of a rare self-incompatibility system in Oleaceae. THE NEW PHYTOLOGIST 2016; 210:1408-17. [PMID: 26833140 DOI: 10.1111/nph.13872] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Accepted: 12/17/2015] [Indexed: 05/21/2023]
Abstract
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.
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Affiliation(s)
- Philippe Vernet
- Université de Lille - Sciences et Technologies, CNRS, UMR 8198 Evo-Eco-Paleo, F59655, Villeneuve d'Ascq, France
| | - Pierre Lepercq
- Université de Lille - Sciences et Technologies, CNRS, UMR 8198 Evo-Eco-Paleo, F59655, Villeneuve d'Ascq, France
| | - Sylvain Billiard
- Université de Lille - Sciences et Technologies, CNRS, UMR 8198 Evo-Eco-Paleo, F59655, Villeneuve d'Ascq, France
| | - Angélique Bourceaux
- Université de Lille - Sciences et Technologies, CNRS, UMR 8198 Evo-Eco-Paleo, F59655, Villeneuve d'Ascq, France
| | - Jacques Lepart
- CEFE-UMR 5175 du CNRS, 1919 route de Mende, 34293, Montpellier Cedex, France
| | - Bertrand Dommée
- CEFE-UMR 5175 du CNRS, 1919 route de Mende, 34293, Montpellier Cedex, France
| | - Pierre Saumitou-Laprade
- Université de Lille - Sciences et Technologies, CNRS, UMR 8198 Evo-Eco-Paleo, F59655, Villeneuve d'Ascq, France
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6
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Henshaw JM, Kokko H, Jennions MD. Direct reciprocity stabilizes simultaneous hermaphroditism at high mating rates: A model of sex allocation with egg trading. Evolution 2015; 69:2129-39. [PMID: 26150086 DOI: 10.1111/evo.12717] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Revised: 06/17/2015] [Accepted: 06/19/2015] [Indexed: 01/14/2023]
Abstract
Simultaneous hermaphroditism is predicted to be unstable at high mating rates given an associated increase in sperm competition. The existence of reciprocal egg trading, which requires both hermaphroditism and high mating rates to evolve, is consequently hard to explain. We show using mathematical models that the presence of a trading economy creates an additional fitness benefit to egg production, which selects for traders to bias their sex allocation toward the female function. This female-biased sex allocation prevents pure females from invading a trading population, thereby allowing simultaneous hermaphroditism to persist stably at much higher levels of sperm competition than would otherwise be expected. More generally, our model highlights that simultaneous hermaphroditism can persist stably when mating opportunities are abundant, as long as sperm competition remains low. It also predicts that reciprocity will select for heavier investment in the traded resource.
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Affiliation(s)
- Jonathan M Henshaw
- Research School of Biology, The Australian National University, Australia.
| | - Hanna Kokko
- Institute of Evolutionary Biology and Environmental Studies, University of Zurich, Switzerland
| | - Michael D Jennions
- Research School of Biology, The Australian National University, Australia
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