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Bashir MA, Bertamini M, Gottardini E, Grando MS, Faralli M. Olive reproductive biology: implications for yield, compatibility conundrum, and environmental constraints. JOURNAL OF EXPERIMENTAL BOTANY 2024; 75:4300-4313. [PMID: 38660967 DOI: 10.1093/jxb/erae190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Accepted: 04/23/2024] [Indexed: 04/26/2024]
Abstract
Olive (Olea europaea L.) is an important Mediterranean tree species with a longstanding history of cultivation, boasting a diverse array of local cultivars. While traditional olive orchards are valued for their cultural and aesthetic significance, they often face economic sustainability challenges in the modern context. The success of both traditional and newly introduced cultivars (e.g. those obtained by cross-breeding) is hindered by self-incompatibility, a prevalent issue for this species that results in low fruit set when limited genetic diversity is present. Further, biological, environmental, and agronomic factors have been shown to interlink in shaping fertilization patterns, hence impacting on the final yield. Climatic conditions during pollination, such as excessive rainfall or high temperatures, can further exacerbate the problem. In this work, we provide an overview of the various factors that trigger the phenomenon of suboptimal fruit set in olive trees. This work provides a comprehensive understanding of the interplay among these factors, shedding light on potential mechanisms and pathways that contribute to the observed outcomes in the context of self-incompatibility in olive.
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Affiliation(s)
- Muhammad Ajmal Bashir
- Centre of Agriculture Food and Environment (C3A), University of Trento, Via E. Mach 1, 38098 San Michele All'Adige (TN), Italy
| | - Massimo Bertamini
- Centre of Agriculture Food and Environment (C3A), University of Trento, Via E. Mach 1, 38098 San Michele All'Adige (TN), Italy
- Research and Innovation Centre - Fondazione Edmund Mach, Via E. Mach, 1, 38098 San Michele All'Adige, (TN), Italy
| | - Elena Gottardini
- Research and Innovation Centre - Fondazione Edmund Mach, Via E. Mach, 1, 38098 San Michele All'Adige, (TN), Italy
| | - Maria Stella Grando
- Centre of Agriculture Food and Environment (C3A), University of Trento, Via E. Mach 1, 38098 San Michele All'Adige (TN), Italy
- Research and Innovation Centre - Fondazione Edmund Mach, Via E. Mach, 1, 38098 San Michele All'Adige, (TN), Italy
| | - Michele Faralli
- Centre of Agriculture Food and Environment (C3A), University of Trento, Via E. Mach 1, 38098 San Michele All'Adige (TN), Italy
- Research and Innovation Centre - Fondazione Edmund Mach, Via E. Mach, 1, 38098 San Michele All'Adige, (TN), Italy
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Castric V, Batista RA, Carré A, Mousavi S, Mazoyer C, Godé C, Gallina S, Ponitzki C, Theron A, Bellec A, Marande W, Santoni S, Mariotti R, Rubini A, Legrand S, Billiard S, Vekemans X, Vernet P, Saumitou-Laprade P. The homomorphic self-incompatibility system in Oleaceae is controlled by a hemizygous genomic region expressing a gibberellin pathway gene. Curr Biol 2024; 34:1967-1976.e6. [PMID: 38626763 DOI: 10.1016/j.cub.2024.03.047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 02/29/2024] [Accepted: 03/25/2024] [Indexed: 04/18/2024]
Abstract
In flowering plants, outcrossing is commonly ensured by self-incompatibility (SI) systems. These can be homomorphic (typically with many different allelic specificities) or can accompany flower heteromorphism (mostly with just two specificities and corresponding floral types). The SI system of the Oleaceae family is unusual, with the long-term maintenance of only two specificities but often without flower morphology differences. To elucidate the genomic architecture and molecular basis of this SI system, we obtained chromosome-scale genome assemblies of Phillyrea angustifolia individuals and related them to a genetic map. The S-locus region proved to have a segregating 543-kb indel unique to one specificity, suggesting a hemizygous region, as observed in all distylous systems so far studied at the genomic level. Only one of the predicted genes in this indel region is found in the olive tree, Olea europaea, genome, also within a segregating indel. We describe complete association between the presence/absence of this gene and the SI types determined for individuals of seven distantly related Oleaceae species. This gene is predicted to be involved in catabolism of the gibberellic acid (GA) hormone, and experimental manipulation of GA levels in developing buds modified the male and female SI responses of the two specificities in different ways. Our results provide a unique example of a homomorphic SI system, where a single conserved gibberellin-related gene in a hemizygous indel underlies the long-term maintenance of two groups of reproductive compatibility.
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Affiliation(s)
- Vincent Castric
- Univ. Lille, CNRS, UMR 8198, Evo-Eco-Paleo, F-59000 Lille, France
| | - Rita A Batista
- Univ. Lille, CNRS, UMR 8198, Evo-Eco-Paleo, F-59000 Lille, France
| | - Amélie Carré
- Univ. Lille, CNRS, UMR 8198, Evo-Eco-Paleo, F-59000 Lille, France
| | - Soraya Mousavi
- CNR, Institute of Biosciences and Bioresources (IBBR), 06128 Perugia, Italy
| | - Clément Mazoyer
- Univ. Lille, CNRS, UMR 8198, Evo-Eco-Paleo, F-59000 Lille, France
| | - Cécile Godé
- Univ. Lille, CNRS, UMR 8198, Evo-Eco-Paleo, F-59000 Lille, France
| | - Sophie Gallina
- Univ. Lille, CNRS, UMR 8198, Evo-Eco-Paleo, F-59000 Lille, France
| | - Chloé Ponitzki
- Univ. Lille, CNRS, UMR 8198, Evo-Eco-Paleo, F-59000 Lille, France
| | - Anthony Theron
- INRAE, CNRGV French Plant Genomic Resource Center, F-31326 Castanet Tolosan, France
| | - Arnaud Bellec
- INRAE, CNRGV French Plant Genomic Resource Center, F-31326 Castanet Tolosan, France
| | - William Marande
- INRAE, CNRGV French Plant Genomic Resource Center, F-31326 Castanet Tolosan, France
| | - Sylvain Santoni
- UMR DIAPC Diversité et adaptation des plantes cultivées, F-34398 Montpellier, France
| | - Roberto Mariotti
- CNR, Institute of Biosciences and Bioresources (IBBR), 06128 Perugia, Italy
| | - Andrea Rubini
- CNR, Institute of Biosciences and Bioresources (IBBR), 06128 Perugia, Italy
| | - Sylvain Legrand
- Univ. Lille, CNRS, UMR 8198, Evo-Eco-Paleo, F-59000 Lille, France
| | - Sylvain Billiard
- Univ. Lille, CNRS, UMR 8198, Evo-Eco-Paleo, F-59000 Lille, France
| | - Xavier Vekemans
- Univ. Lille, CNRS, UMR 8198, Evo-Eco-Paleo, F-59000 Lille, France
| | - Philippe Vernet
- Univ. Lille, CNRS, UMR 8198, Evo-Eco-Paleo, F-59000 Lille, France
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Vuletin Selak G, Baruca Arbeiter A, Cuevas J, Perica S, Pujic P, Raboteg Božiković M, Bandelj D. Seed Paternity Analysis Using SSR Markers to Assess Successful Pollen Donors in Mixed Olive Orchards. PLANTS 2021; 10:plants10112356. [PMID: 34834719 PMCID: PMC8624852 DOI: 10.3390/plants10112356] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Revised: 10/19/2021] [Accepted: 10/28/2021] [Indexed: 11/22/2022]
Abstract
The olive tree (Olea europaea L.) is a wind-pollinated crop that exhibits an extreme alternate bearing habit. To improve fruit set, several methods have been used to determine the most successful compatible combinations of cultivars. In this study, priority is given to seed paternity analysis based on simple sequence repeats (SSRs), microsatellite markers used for the identification of potential pollen donors of cultivar ‘Oblica’ in a mixed olive orchard during two consecutive years. Seven microsatellite primers were successfully used to examine the paternity of olive embryos from ‘Oblica’ mother trees. Embryos were considered as a product of self-fertilization if only maternal alleles were present, but not a single case of self-fertilization was found among all the embryos analyzed. Two dominant pollen donors were not the closest nor the cultivars with the highest number of trees in the orchard, suggesting that cross-compatibility may have a key role in determining pollen donor success. In our earlier studies, pollen tube growth and fertilization success correlated with fruit set when controlled crosses between cultivars were performed; however, some discrepancy might appear compared to paternity analyses when mother trees have a free choice among different pollen sources from cultivars growing in their surroundings.
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Affiliation(s)
- Gabriela Vuletin Selak
- Department of Plant Sciences, Institute for Adriatic Crops and Karst Reclamation, 21000 Split, Croatia; (S.P.); (M.R.B.)
- Centre of Excellence for Biodiversity and Molecular Plant Breeding (CoE CroP-BioDiv), Svetošimunska Cesta 25, 10000 Zagreb, Croatia
- Correspondence: ; Tel.: +385-21-434-436
| | - Alenka Baruca Arbeiter
- Faculty of Mathematics, Natural Sciences and Information Technologies, University of Primorska, 6000 Koper, Slovenia; (A.B.A.); (D.B.)
| | - Julián Cuevas
- Department of Agronomy, University of Almería, CeiA3, La Cañada de San Urbano, s/n, 04120 Almería, Spain;
| | - Slavko Perica
- Department of Plant Sciences, Institute for Adriatic Crops and Karst Reclamation, 21000 Split, Croatia; (S.P.); (M.R.B.)
- Centre of Excellence for Biodiversity and Molecular Plant Breeding (CoE CroP-BioDiv), Svetošimunska Cesta 25, 10000 Zagreb, Croatia
| | - Petar Pujic
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS, INRAE, VetAgro Sup, UMR5557 Ecologie Microbienne, F-69622 Villeurbanne, France;
| | - Marina Raboteg Božiković
- Department of Plant Sciences, Institute for Adriatic Crops and Karst Reclamation, 21000 Split, Croatia; (S.P.); (M.R.B.)
- Centre of Excellence for Biodiversity and Molecular Plant Breeding (CoE CroP-BioDiv), Svetošimunska Cesta 25, 10000 Zagreb, Croatia
| | - Dunja Bandelj
- Faculty of Mathematics, Natural Sciences and Information Technologies, University of Primorska, 6000 Koper, Slovenia; (A.B.A.); (D.B.)
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A Dual-Successive-Screen Model at Pollen/Stigma and Pollen Tube/Ovary Explaining Paradoxical Self-Incompatibility Diagnosis in the Olive Tree—An Interpretative Update of the Literature. PLANTS 2021; 10:plants10091938. [PMID: 34579470 PMCID: PMC8466169 DOI: 10.3390/plants10091938] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 09/04/2021] [Accepted: 09/10/2021] [Indexed: 01/13/2023]
Abstract
The ‘pollen test’ and ‘fruit set test’ following controlled crossing combinations of parents are the most commonly used methods for pollination incompatibility studies in Olea europaea L. Self-incompatibility (SI), with diagnoses based on the pollen test and pollen germination, indicating self-compatibility, is not always followed by fruit set in this species. To solve this dispute, we have reconciled all observations into a new model. Mismatches between field and laboratory data and between methods are resolved by the dual-successive-screen model (DSSM) supposing two different loci for the expression of the two SI mechanisms. Pollen/stigma is controlled by diallelic SI, or DSI, inferring two G1 and G2 compatibility/incompatibility (C/I) groups for varieties, whereas pollen tubes in ovaries are controlled by poly-allelic SI or PASI with twenty C/I groups. To explain the selfing of varieties, we have suggested that some determinants in the pollen tube and stigma are unstable and degrade (DS-D for degradation of S-determinant) after three to five days, enabling some pollen tubes to avoid being rejected, hence reaching ovules. DSI and PASI in the DSSM and DS-D mechanisms, plus the andromonoecy of the olive tree, complexify SI studies. Inferences from DSSM and DS-D mechanisms in olive orchard practice are detailed.
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