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Barazani O, Dag A, Dunseth Z. The history of olive cultivation in the southern Levant. FRONTIERS IN PLANT SCIENCE 2023; 14:1131557. [PMID: 36909452 PMCID: PMC9996078 DOI: 10.3389/fpls.2023.1131557] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/25/2022] [Accepted: 01/30/2023] [Indexed: 06/18/2023]
Abstract
The olive tree (Olea europaea L. subsp. europaea var. europaea) is one of the most important crops across the Mediterranean, particularly the southern Levant. Its regional economic importance dates at least to the Early Bronze Age (~3600 BCE) and its cultivation contributed significantly to the culture and heritage of ancient civilizations in the region. In the southern Levant, pollen, pits and wood remains of wild olives (O. europaea subsp. europaea var. sylvestris) has been found in Middle Pleistocene sediments dating to approximately 780 kya, and are present in numerous palynological sequences throughout the Pleistocene and into the Holocene. Archeological evidence indicates the olive oil production from at least the Pottery Neolithic to Chalcolithic transition (~7600-7000 BP), and clear evidence for cultivation by, 7000 BP. It is hypothesized that olive cultivation began through the selection of local genotypes of the wild var. sylvestris. Local populations of naturally growing trees today have thus been considered wild relatives of the olive. However, millennia of cultivation raises questions about whether genuine populations of var. sylvestris remain in the region. Ancient olive landraces might thus represent an ancient genetic stock closer to the ancestor gene pool. This review summarizes the evidence supporting the theory that olives were first cultivated in the southern Levant and reviews our genetic work characterizing local ancient cultivars. The significance and importance of old cultivars and wild populations are discussed, given the immediate need to adapt agricultural practices and crops to environmental degradation and global climate change.
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Affiliation(s)
- Oz Barazani
- Agricultural Research Organization, Institute of Plant Sciences, Department of Vegetables and Field Crops, Rishon LeZion, Israel
| | - Arnon Dag
- Agricultural Research Organization, Institute of Plant Sciences, Department of Fruit Tree Sciences, Gilat Research Center, Gilat, Israel
| | - Zachary Dunseth
- Joukowsky Institute for Archaeology and the Ancient World, Brown University, Providence, RI, United States
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Julca I, Marcet-Houben M, Cruz F, Gómez-Garrido J, Gaut BS, Díez CM, Gut IG, Alioto TS, Vargas P, Gabaldón T. Genomic evidence for recurrent genetic admixture during the domestication of Mediterranean olive trees (Olea europaea L.). BMC Biol 2020; 18:148. [PMID: 33100219 PMCID: PMC7586694 DOI: 10.1186/s12915-020-00881-6] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Accepted: 09/27/2020] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND Olive tree (Olea europaea L. subsp. europaea, Oleaceae) has been the most emblematic perennial crop for Mediterranean countries since its domestication around 6000 years ago in the Levant. Two taxonomic varieties are currently recognized: cultivated (var. europaea) and wild (var. sylvestris) trees. However, it remains unclear whether olive cultivars derive from a single initial domestication event followed by secondary diversification, or whether cultivated lineages are the result of more than a single, independent primary domestication event. To shed light into the recent evolution and domestication of the olive tree, here we analyze a group of newly sequenced and available genomes using a phylogenomics and population genomics framework. RESULTS We improved the assembly and annotation of the reference genome, newly sequenced the genomes of twelve individuals: ten var. europaea, one var. sylvestris, and one outgroup taxon (subsp. cuspidata)-and assembled a dataset comprising whole genome data from 46 var. europaea and 10 var. sylvestris. Phylogenomic and population structure analyses support a continuous process of olive tree domestication, involving a major domestication event, followed by recurrent independent genetic admixture events with wild populations across the Mediterranean Basin. Cultivated olives exhibit only slightly lower levels of genetic diversity than wild forms, which can be partially explained by the occurrence of a mild population bottleneck 3000-14,000 years ago during the primary domestication period, followed by recurrent introgression from wild populations. Genes associated with stress response and developmental processes were positively selected in cultivars, but we did not find evidence that genes involved in fruit size or oil content were under positive selection. This suggests that complex selective processes other than directional selection of a few genes are in place. CONCLUSIONS Altogether, our results suggest that a primary domestication area in the eastern Mediterranean basin was followed by numerous secondary events across most countries of southern Europe and northern Africa, often involving genetic admixture with genetically rich wild populations, particularly from the western Mediterranean Basin.
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Affiliation(s)
- Irene Julca
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, 08003, Barcelona, Spain
- Department of Experimental and Health Sciences, Universitat Pompeu Fabra (UPF), 08003, Barcelona, Spain
- Universitat Autònoma de Barcelona (UAB), 08193, Barcelona, Spain
| | - Marina Marcet-Houben
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, 08003, Barcelona, Spain
- Department of Experimental and Health Sciences, Universitat Pompeu Fabra (UPF), 08003, Barcelona, Spain
- Present address: Barcelona Supercomputing Centre (BSC-CNS), and Institute for Research in Biomedicine (IRB), Barcelona, Spain
| | - Fernando Cruz
- CNAG-CRG, Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology (BIST), Baldiri i Reixac 4, 08028, Barcelona, Spain
| | - Jèssica Gómez-Garrido
- CNAG-CRG, Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology (BIST), Baldiri i Reixac 4, 08028, Barcelona, Spain
| | - Brandon S Gaut
- Department Ecology and Evolutionary Biology, University of California Irvine, Irvine, CA, 92697, USA
| | | | - Ivo G Gut
- Department of Experimental and Health Sciences, Universitat Pompeu Fabra (UPF), 08003, Barcelona, Spain
- CNAG-CRG, Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology (BIST), Baldiri i Reixac 4, 08028, Barcelona, Spain
| | - Tyler S Alioto
- Department of Experimental and Health Sciences, Universitat Pompeu Fabra (UPF), 08003, Barcelona, Spain
- CNAG-CRG, Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology (BIST), Baldiri i Reixac 4, 08028, Barcelona, Spain
| | - Pablo Vargas
- Royal Botanical Garden of Madrid. Consejo Superior de Investigaciones Científicas (CSIC), 28014, Madrid, Spain
| | - Toni Gabaldón
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, 08003, Barcelona, Spain.
- Department of Experimental and Health Sciences, Universitat Pompeu Fabra (UPF), 08003, Barcelona, Spain.
- Present address: Barcelona Supercomputing Centre (BSC-CNS), and Institute for Research in Biomedicine (IRB), Barcelona, Spain.
- Institució Catalana de Recerca i Estudis Avançats (ICREA), Pg. Lluís Companys 23, 08010, Barcelona, Spain.
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Haddad B, Gristina AS, Mercati F, Saadi AE, Aiter N, Martorana A, Sharaf A, Carimi F. Molecular Analysis of the Official Algerian Olive Collection Highlighted a Hotspot of Biodiversity in the Central Mediterranean Basin. Genes (Basel) 2020; 11:E303. [PMID: 32183122 PMCID: PMC7140851 DOI: 10.3390/genes11030303] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 03/04/2020] [Accepted: 03/09/2020] [Indexed: 12/20/2022] Open
Abstract
Genetic diversity and population structure studies of local olive germplasm are important to safeguard biodiversity, for genetic resources management and to improve the knowledge on the distribution and evolution patterns of this species. In the present study Algerian olive germplasm was characterized using 16 nuclear (nuSSR) and six chloroplast (cpSSR) microsatellites. Algerian varieties, collected from the National Olive Germplasm Repository (ITAFV), 10 of which had never been genotyped before, were analyzed. Our results highlighted the presence of an exclusive genetic core represented by 13 cultivars located in a mountainous area in the North-East of Algeria, named Little Kabylie. Comparison with published datasets, representative of the Mediterranean genetic background, revealed that the most Algerian varieties showed affinity with Central and Eastern Mediterranean cultivars. Interestingly, cpSSR phylogenetic analysis supported results from nuSSRs, highlighting similarities between Algerian germplasm and wild olives from Greece, Italy, Spain and Morocco. This study sheds light on the genetic relationship of Algerian and Mediterranean olive germplasm suggesting possible events of secondary domestication and/or crossing and hybridization across the Mediterranean area. Our findings revealed a distinctive genetic background for cultivars from Little Kabylie and support the increasing awareness that North Africa represents a hotspot of diversity for crop varieties and crop wild relative species.
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Affiliation(s)
- Benalia Haddad
- Département de Productions Végétales, Laboratoire Amélioration Intégrative Des Productions Végétales (AIPV, C2711100), Ecole Nationale Supérieure Agronomique (ENSA), Hassan Badi, El Harrach, Algiers 16000, Algeria;
| | - Alessandro Silvestre Gristina
- Institute of Biosciences and BioResources, National Research Council (CNR), Research Division of Palermo, Corso Calatafimi 414, 90129 Palermo, Italy; (F.M.); (A.M.); (A.S.); (F.C.)
| | - Francesco Mercati
- Institute of Biosciences and BioResources, National Research Council (CNR), Research Division of Palermo, Corso Calatafimi 414, 90129 Palermo, Italy; (F.M.); (A.M.); (A.S.); (F.C.)
| | - Abd Elkader Saadi
- University Hassiba Benbouali, Faculty of Science of Nature and Life, Plant Biotechnology Laboratory, BP 151, Chlef 02000, Algeria;
| | - Nassima Aiter
- Université Saad Dahleb-Blida 1, Faculté des Sciences de la Nature et de la Vie, Laboratoire de Biotechnologie des Productions Végétales, Département de Biotechnologies, Blida 09000, Algeria
- Laboratoire de culture in vitro, Département central, Institut Technique de l’Arboriculture Fruitière et de la Vigne, ITAFV, Algiers 16000, Algeria
| | - Adriana Martorana
- Institute of Biosciences and BioResources, National Research Council (CNR), Research Division of Palermo, Corso Calatafimi 414, 90129 Palermo, Italy; (F.M.); (A.M.); (A.S.); (F.C.)
| | - Abdoallah Sharaf
- Institute of Biosciences and BioResources, National Research Council (CNR), Research Division of Palermo, Corso Calatafimi 414, 90129 Palermo, Italy; (F.M.); (A.M.); (A.S.); (F.C.)
- Institute of Molecular Biology of Plants, Biology Centre, CAS, Branišovská 31, 37005 České Budějovice, Czech Republic
| | - Francesco Carimi
- Institute of Biosciences and BioResources, National Research Council (CNR), Research Division of Palermo, Corso Calatafimi 414, 90129 Palermo, Italy; (F.M.); (A.M.); (A.S.); (F.C.)
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Gros‐Balthazard M, Besnard G, Sarah G, Holtz Y, Leclercq J, Santoni S, Wegmann D, Glémin S, Khadari B. Evolutionary transcriptomics reveals the origins of olives and the genomic changes associated with their domestication. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2019; 100:143-157. [PMID: 31192486 PMCID: PMC6851578 DOI: 10.1111/tpj.14435] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 05/29/2019] [Accepted: 06/03/2019] [Indexed: 05/11/2023]
Abstract
The olive (Olea europaea L. subsp. europaea) is one of the oldest and most socio-economically important cultivated perennial crop in the Mediterranean region. Yet, its origins are still under debate and the genetic bases of the phenotypic changes associated with its domestication are unknown. We generated RNA-sequencing data for 68 wild and cultivated olive trees to study the genetic diversity and structure both at the transcription and sequence levels. To localize putative genes or expression pathways targeted by artificial selection during domestication, we employed a two-step approach in which we identified differentially expressed genes and screened the transcriptome for signatures of selection. Our analyses support a major domestication event in the eastern part of the Mediterranean basin followed by dispersion towards the West and subsequent admixture with western wild olives. While we found large changes in gene expression when comparing cultivated and wild olives, we found no major signature of selection on coding variants and weak signals primarily affected transcription factors. Our results indicated that the domestication of olives resulted in only moderate genomic consequences and that the domestication syndrome is mainly related to changes in gene expression, consistent with its evolutionary history and life history traits.
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Affiliation(s)
- Muriel Gros‐Balthazard
- AGAP, University Montpellier, CIRAD, INRAMontpellier SupAgroMontpellierFrance
- Present address:
New York University Abu Dhabi (NYUAD), Center for Genomics and Systems BiologySaadiyat IslandAbu DhabiUnited Arab Emirates
| | | | - Gautier Sarah
- AGAP, University Montpellier, CIRAD, INRAMontpellier SupAgroMontpellierFrance
| | - Yan Holtz
- AGAP, University Montpellier, CIRAD, INRAMontpellier SupAgroMontpellierFrance
| | - Julie Leclercq
- AGAP, University Montpellier, CIRAD, INRAMontpellier SupAgroMontpellierFrance
| | - Sylvain Santoni
- AGAP, University Montpellier, CIRAD, INRAMontpellier SupAgroMontpellierFrance
| | - Daniel Wegmann
- Department of BiologyUniversity of FribourgFribourgSwitzerland
- Swiss Institute of BioinformaticsFribourgSwitzerland
| | - Sylvain Glémin
- CNRSUniversité de RennesECOBIO (Ecosystèmes, biodiversité, évolution) − UMR 6553F‐35000RennesFrance
- Department of Ecology and GeneticsEvolutionary Biology CentreUppsala UniversityUppsalaSweden
| | - Bouchaib Khadari
- AGAP, University Montpellier, CIRAD, INRAMontpellier SupAgroMontpellierFrance
- Conservatoire Botanique National MéditerranéenUMR AGAPMontpellierFrance
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Besnard G, Terral JF, Cornille A. On the origins and domestication of the olive: a review and perspectives. ANNALS OF BOTANY 2018; 121:385-403. [PMID: 29293871 PMCID: PMC5838823 DOI: 10.1093/aob/mcx145] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Accepted: 10/12/2017] [Indexed: 05/18/2023]
Abstract
Background Unravelling domestication processes is crucial for understanding how species respond to anthropogenic pressures, forecasting crop responses to future global changes and improving breeding programmes. Domestication processes for clonally propagated perennials differ markedly from those for seed-propagated annual crops, mostly due to long generation times, clonal propagation and recurrent admixture with local forms, leading to a limited number of generations of selection from wild ancestors. However, additional case studies are required to document this process more fully. Scope The olive is an iconic species in Mediterranean cultural history. Its multiple uses and omnipresence in traditional agrosystems have made this species an economic pillar and cornerstone of Mediterranean agriculture. However, major questions about the domestication history of the olive remain unanswered. New paleobotanical, archeological, historical and molecular data have recently accumulated for olive, making it timely to carry out a critical re-evaluation of the biogeography of wild olives and the history of their cultivation. We review here the chronological history of wild olives and discuss the questions that remain unanswered, or even unasked, about their domestication history in the Mediterranean Basin. We argue that more detailed ecological genomics studies of wild and cultivated olives are crucial to improve our understanding of olive domestication. Multidisciplinary research integrating genomics, metagenomics and community ecology will make it possible to decipher the evolutionary ecology of one of the most iconic domesticated fruit trees worldwide. Conclusion The olive is a relevant model for improving our knowledge of domestication processes in clonally propagated perennial crops, particularly those of the Mediterranean Basin. Future studies on the ecological and genomic shifts linked to domestication in olive and its associated community will provide insight into the phenotypic and molecular bases of crop adaptation to human uses.
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Affiliation(s)
- Guillaume Besnard
- CNRS-UPS-ENSFEA-IRD, EDB, UMR 5174, Université Paul Sabatier, Toulouse Cedex , France
| | - Jean-Frédéric Terral
- ISEM, UMR 5554, CNRS-Université de Montpellier-IRD-EPHE, Equipe Dynamique de la Biodiversité, Anthropo-écologie, Montpellier Cedex, France
- International Associated Laboratory (LIA, CNRS) EVOLea, Zürich, Switzerland
| | - Amandine Cornille
- Center for Adaptation to a Changing Environment, ETH Zürich, Zürich, Switzerland
- GQE - Le Moulon, INRA, Univ. Paris-Sud, CNRS, AgroParisTech, Université Paris-Saclay, Gif-sur-Yvette, France
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