OlSiFaComp : A database for Olea. Olive self-incompatibility flower allelic composition

Data on olive cross and selfing studies were numerous and dispersed in literature. Varieties were list in lines, and each line correspond to one data – bag, pollen test, paternity tests, ...To compare data in bags standardization was achieved based on 100 hermaphroditic flowers

New hypothesis elucidates self-incompatibility in the olive tree regarding S-alleles dominance relationships as in the sporophytic model

Publication Inra prise en compte dans l'analyse bibliométrique des publications scientifiques mondiales sur les Fruits, les Légumes et la Pomme de terre. Période 2000-2012. http://prodinra.inra.fr/record/256699Most olive varieties are not strictly self-incompatible, nevertheless, they request foreign pollen to enhance fruit yield, and consequently orchards should contain pollinisers to ensure fruit set of the main variety. The best way to choose pollinisers is to experiment numerous crosses in a diallel design. Here, the genetic mode of inheritance of SI in the olive is deciphered and it does not correspond to the GSI type, but to the SSI type. It leaves S-allele dominance relationship expression in the male (pollen and pollen tube), but not in the female (stigma and style). Thus, a pair-wise combination of varieties may be inter-compatible in one direction (male to female, or female to male) and inter-incompatible in the other direction. Dominance relationships also explain different levels of self-pollination observed in varieties. Little efficient pollinisers were found and predicted in varieties; nevertheless, some new efficient pair-wise allele combinations are predicted and could be created. This model enables one to forecast compatibility without waiting for several years of yield records and to choose pollinisers in silico

Using multiple types of molecular markers to understand olive phylogeography

UMR DAP, équipe AFEFInternational audienc

An insertion of oleate desaturase homologous sequence silences via siRNA the functional gene leading to high oleic acid content in sunflower seed oil

International audienceClassical sunflower varieties display a high linoleic acid content in their seeds [low oleic (LO) varieties] whereas genotypes carrying the Pervenets mutation display an increased oleic acid content of above 83% [high oleic (HO) varieties]. Despite the advantage in health terms of oleic acid, the nature of the mutation was still unknown. Previous work reported that HO genotypes carried a specific oleate desaturase (OD) allele. This enzyme catalyses the desaturation of oleic acid into linoleic acid. The present work demonstrates that this allele is organised in two parts: the first section present in both HO and LO genotypes carries a normal OD gene, the second section is specific to HO genotypes and carries OD duplications. The study of mRNA accumulation in LO and HO seeds revealed that the mutation is dominant and induces an OD mRNA down-regulation. Furthermore, OD small interfering RNA, characteristic of gene silencing, accumulated specifically in HO seeds. Considered together, these observations show that the mutation is associated with OD duplications leading to gene silencing of the OD gene and consequently, to oleic acid accumulation. This finding allowed the development of molecular markers characterising the mutation that can be used in breeding programmes to facilitate the selection of HO genotypes

L'olivier : l'olivier dans notre civilisation et notre culture

Correspondance : [email protected] audienceL'olivier occupe une place ancestrale dans les civilisation méditerranéennes. Bien au-delà, il accompagne les textes fondateurs de notre culture: bible, torah, talmud, coran, grands textes classiques grecs... Arbre des dieux, symbole de force, de longévité et de paix, il tend toujours vers la lumière. Il incarne une manière de vivr

Genetic diversity and gene flow between the wild olive (oleaster, Olea europaea L.) and the olive : several Plio-Pleistocene refuge zones in the Mediterranean basin suggested by simple sequence repeats analysis

Correspondance: [email protected] Publication Inra prise en compte dans l'analyse bibliométrique des publications scientifiques mondiales sur les Fruits, les Légumes et la Pomme de terre. Période 2000-2012. http://prodinra.inra.fr/record/256699International audienceAim The oleaster is believed to have originated in the eastern Mediterranean, implying that those in the western Mediterranean basin could be feral. Several studies with different molecular markers (isozymes, random amplified polymorphic DNA, amplified fragment length polymorphism) have shown a cline between the eastern and the western populations, which supports this hypothesis. To reconstruct the post-glacial colonization history and establish a relationship between olive and oleaster populations in the Mediterranean basin, analyses were carried out on the genetic variation of chloroplast DNA (chlorotype) and at 12 unlinked simple sequence repeat (SSR) loci, sampling a total of 20 oleaster groves. Location: This is the first known large-scale molecular study of SSR loci based on samples of both oleasters and cultivars from the entire Mediterranean basin.Methods Samples were taken from 166 oleasters in 20 groves of modern populations, and 40 cultivars to represent molecular diversity in the cultivated olive. The Bayesian method and admixture analysis were used to construct the ancestral populations (RPOP; reconstructed panmictic oleaster populations) andto estimate the proportion of each RPOP in each tree. If one tree can be assigned to two or more RPOPs, it can be regarded as a product of hybridization between trees from different populations (i.e. admix origin).Results: On this first examination of the SSR genetic diversity in the olive and oleaster, it was found to be structured in seven RPOPs in both eastern and western populations. Based on different population genetic methods, it was shown that: (1) oleasters are equally present in the eastern and the western Mediterranean, (2) are native, and (3) are not derived from cultivars. Chlorotypes (one and three in the eastern and western Mediterranean, respectively) revealed fruit displacement for the oleasters.Main conclusions: Oleaster genetic diversity is divided into seven regions that could overlay glacial refuges. The gradient, or cline, of genetic diversity revealed by chloroplast and SSR molecular markers was explained by oleaster recolonization of the Mediterranean basin from refuges after the last glacial event, located in both eastern and western regions. It is likely that gene flow has occurred in oleasters mediated by cultivars spread by human migration or through trade. Animals may have helped spread oleasters locally, but humans have probably transported olives but not oleaster fruits over long distances. We found that cultivars may have originated in several RPOPs, and thus, some may have a more complex origin than expected initially

L'olea maroccana, pourquoi en faire une sous-espèce?

National audienceAu sud du maroc existent des populations d'olea dont la morphologie est intermédiaire entre la sous-espèce laperrinei et la sous-espèce europaea. Longtemps ignoré ou négligé, ce taxon d'olea a reçu des noms divers, dont celui de O. maroccana. Ce n'est que récemment, en 2001, que la morphologie et le marquage moléculaire ont permis de considérer cet olivier comme sous-espèce de l'olea europaea. La phénologie est introduite ici comme un critère nouveau. Les principales caractéristiques de cet olivier endémique du Maroc sont exposés. Les deux sous-espèces europaea et maroccana existent en sympatrie, ce qui est une situation originale et interroge sur leur évolution

Specific features in the olive self-incompatibility system: a method to decipher S-allele pairs based on fruit settings

AGAP : équipe DAVEMInternational audienceOlive fruit production is dependent on wind pollination, and recently sporophytic self-incompatibility has been advocated to function with six S-alleles. The aim here is to show fruit setting data gathered from literature can be interpreted and their standardization help to release firm conclusions on the S-allele pair carried by most varieties. Under a bag, fruit settings for mates do not allow to infer inter-compatibility of pairs of mates. Each variety displays a different number of flowers per inflorescence, and for a given proportion of hermaphrodite flowers, fruit sets per hermaphrodite flowers were calculated. Thus, broad fruit set data were standardized per 100 hermaphrodite flowers. The ratio fruit sets from self-pollination and fruit sets from crosses are commonly referred to fruit sets after open pollination, as the index of self-incompatibility (ISI) and the index for cross inter-compatibility (ICOI), respectively. Open pollination rate (OP-R) is considered to be the best rate of fruit sets for a variety. ICOI values were classified with the threshold at 0.6 to rank a pair of varieties as inter-incompatible and inter-compatible. Before, we have proceeded by trials and errors. Here we showed that rationale reasoning is efficient to analyze fruit settings. Computations on ICOI showed that matings that succeeded are more confident than matings that failed, because pollen efficiency appeared insufficient. Computations on ISI revealed high correlations between SI and co-dominant S-allele pairs as for SC and S-allele pairs sharing dominance relationships. Thus, the sporophytic self-incompatibility (SSI) model will help geneticists to unravel the S-allele series and to predict suitable pollinizers in olive orchards. Moreover, compensation for OP-R deficiency in orchards could be achieved by supplementing suitable pollinizers computed in silico

De l’olivier à l’oléastre : origine et domestication de l’Olea europaea L. dans le Bassin méditerranéen

National audienceThe olive tree is the cultivated form of the wild oleaster, both of which belong to the subspecies europaea of Olea europaea and are naturally distributed all around the Mediterranean Sea. In addition to these, some trees escaped from cultivation resemble oleasters by their physiognomy. No specific morphologic marker unambiguously differentiates the three forms. Olive cultivars today show a wide diversity in their morphology and phenology. Olives are important economically in Mediterranean countries, and olive oils carrying the taste and aroma of the fruit are the base of a new gastronomy also economically significant. Olive trees fashion landscapes and prevent erosion, and a social culture is associated with their products. Oleasters are endangered due to recurrent gene flow from the olive tree, human impact on forests and climate change. Olive cultivars result from a long process of selection in diverse environments that have had different cultural practices and traditions ever since the olive tree began accompanying human migration in the Neolithic period. The first domestication had occurred by -5800 B.P. around the eastern Mediterranean basin. Olive cultivars are deeply differentiated according to ultimate use — for oil, table or mixed. Their origins are unknown and the country of origin is only an indication of where they come from. Cultivars and oleasters are wind-pollinated and outcrossing is the rule. Molecular markers have recently made it possible to study the diversity of olive trees and thus to attempt to verify myths and beliefs about their origins. Relations between cultivars can now be established with several types of markers. Domestication events must have appeared in several sites around eastern and western Mediterranean localities since cultivars have inherited cytotypes of local oleasters, and this probably occurred simultaneously. Human migrations displaced cultivars, leading to gene flow: local oleasters generate new forms and new cultivated genotypes. Cytoplasmic markers show at least four separate origins of olive trees from oleasters, and SSRs show at least seven. Molecular markers have enabled us to show that each cultivar corresponds to one clone with a few exceptions. This means that cultivars were propagated from a single tree, with some exceptions that may be due to mixing two or three sister progenies of one tree. Although oleasters originate from seven different refuge areas, gene flow caused by cultivar displacement has disturbed this structure. Some cultivars also have their origin in some of these primary populations but others appeared as hybrids between two or three of these zones. This suggests that gene flow occurred between local oleasters and cultivars introduced by human migrationsDe l’olivier à l’oléastre : origine et domestication de l’Olea europaea L. dans le Bassin méditerranéen Keywords : VEGETAL PRODUCTIONS, NATURAL RESOURCES AND ENVIRONMENTRésumé : L’olivier occupe la 24 e place des 35 espèces les plus cultivées dans le monde. La diversité phénologique des cultivars est remarquable et l’intérêt économique de l’espèce est majeur. Pourtant peu d’études ont porté sur la domestication de l’olivier et sur les relations entre l’olivier et sa forme sauvage, l’oléastre. Les marqueurs moléculaires rendent possible l’étude de la structure génétique des cultivars, des flux géniques et des relations entre la forme cultivée et sauvage. L’analyse de la diversité actuelle de la sous-espèce europaea d’Olea europea permet de remonter le temps et d’analyser les mécanismes qui ont conduit à cette diversité. Les processus utilisés donnent un panorama de la diversité après les glaciations et permettent de situer globalement les zones refuges qui apparaissent nombreuses et génétiquement très structurées. La comparaison avec la connaissance populaire montre que, chez cette espèce, l’histoire a été enjolivée, probablement pour combler l’absence de données historiques. L’origine de l’olivier à partir de l’oléastre ne fait plus de doute à l’est comme à l’ouest de la mer Méditerranée. Cependant, la diversité de l’oléastre et de l’olivier est maximale à l’ouest. L’archéologie confirmant la présence de l’oléastre à l’ouest, l’origine de la sous-espèce europaea est donc à reconsidére

'Comment on Saumitou et al. (2017): Elucidation of the genetic architecture of self-incompatibility in olive: evolutionary consequences and perspectives for orchard management'

The new self-incompatibility system (SI) was presented by Saumitou-Laprade, Vernet, Vekemans et al. (2017). Evolutionary Applications based on 89 crosses between varieties in the olive tree. Four main points are not clear. We are examining here as follows: (i) the assertion that the self-incompatibility system is sporophytic was not sustained by pollen germination data; (ii) surprisingly, the new model does not explain that about one-third of pairwise combinations of olive varieties leads to asymmetric fruit setting; (iii) DNA preparation from one seed may contain two embryos, and thus, embryos should be separated before seed extraction; (iv) although effective self-fertility in olive varieties was reported by many studies, the DSI model fails to explain self-fertility in some olive varieties. Moreover, we cannot discuss result data, as science cannot be verified because variety names were encoded, this does not allow comparison of data with previous works. The DSI model on olive self-incompatibility should explain more features than the model based on four dominance levels shared by six S-alleles. Perspectives for orchard management based on this model may face serious limitations. An olive variety does not have a fifty percent chance of cross-incompatibility, but surely fewer, and thus, the sporophytic system limits fruit production. Evolutionary perspectives of self-incompatibility in Oleaceae should include data from the Jasmineae tribe that displays heterostyly SI