Thierry Robert’s research while affiliated with University of Paris-Saclay and other places

Background/Objectives: Lebanon, one of the oldest centers of grapevine (Vitis vinifera L.) cultivation, is home to a rich diversity of local grape varieties. This biodiversity is linked to the country’s unique topography and millennia of cultural history. However, the wine industry primarily utilizes international varieties, putting many local varieties at risk of extinction. Methods: In this study, we analyzed 202 samples from old vineyards, home gardens, and private collections using 21 microsatellite markers to assess their identity and genetic diversity. Results: A total of 67 different genotypes were identified, with 34 not matching any existing profiles in the consulted databases, based on comparisons with the European Vitis Database, the Vitis International Variety Catalogue (VIVC), and the databases established in two previous studies conducted in Armenia and Lebanon. Cluster analyses revealed Lebanon’s rich diversity of local grape varieties, highlighting cases of synonymy, homonymy, and misnaming. All loci were polymorphic, with 228 alleles and an average of 11.4 alleles being detected. The highest number of alleles was observed at the VVIV67 locus (19 alleles), while the lowest was found at the VVIQ52 and VVIN73 loci (5 alleles). The observed heterozygosity was 0.732, slightly below the expected value of 0.757, with gene diversity varying among the markers. Conclusions: Of the 67 genetic profiles identified, 34 are absent from national and international databases, underscoring Lebanon as a hotspot for grapevine genetic diversity. This unique genetic variation, which includes several synonyms due to geographic isolation, could provide valuable opportunities for producing distinctive wines and emphasizes the need for further research and documentation.

Evolutionary biologists recognize that understanding the phylogenetic history of closely related species is challenging without considering their population genetics history. The taxonomy of Magnolia sect. Talauma in Cuba has long been debated, with several changes in taxon delimitations. All these taxonomic revisions were based exclusively on leaf morphological characteristics of a few individuals, limiting their ability to elucidate taxon boundaries. Recent studies have focused on conservation genetics and species delimitation of Cuban magnolias, based on ecological, morphological and genetic data. Here, we use full plastome sequences and microsatellite data to infer phylogenetic relationships and potential historical migration events among species in Magnolia sect. Talauma in Cuba. Bayesian phylogeny and TreeMix were used to understand the phylogenetic relationships. Based on this, Magnolia sect. Talauma in Cuba does not comprise a monophyletic group. The data continue to show a highly supported unresolved species complex in the taxa of Magnolia subsect. Talauma from north-eastern Cuba. From a taxonomic point of view, our results do not entirely support the most recent taxonomic review proposed for the family in Cuba.

Abstract: Allopolyploidy is considered as a principal driver that shaped angiosperms’ evolution in terms of diversification and speciation. Despite the unexpected high frequency of polyploidy that was recently discovered in the coniferous genus Juniperus, little is known about the origin of these polyploid taxa. Here, we conducted the first study devoted to deciphering the origin of the only hexaploid taxon in Juniperus along with four of its closely related tetraploid taxa using AFLP markers with four primers combinations. Phylogenetic analysis revealed that the 10 studied species belong to 2 major clusters. J. foetidissima appeared to be more related to J. thurifera, J. sabina, and J. chinensis. The Bayesian clustering analysis showing a slight variation in genetic admixture between the studied populations of J. foetidissima, suggesting an allopolyploid origin of this species involving J. thurifera and J. sabina lineages, although a purely autopolyploidy origin of both J. thurifera and J. foetidissima cannot be ruled out. The admixed genetic pattern revealed for J. seravschanica showed that the tetraploid cytotypes of this species originated from allopolyploidy, whereas no clear evidence of hybridization in the origin of the tetraploid J. thurifera and J. chinensis was detected. This study provides first insights into the polyploidy origin of the Sabina section and highlights the potential implication of allopolyploidy in the evolution of the genus Juniperus. Further analyses are needed for a more in-depth understanding of the evolutionary scenarios that produced the observed genetic patterns.

The taxonomy of Magnolia subsect. Talauma in Cuba has long been debated with many changes in the last few years. New evidence based on ecological, morphological and genetic data has indicated the occurrence of three taxa, with changes in the limits from the latest taxonomic treatment. In this sense, the taxonomy and nomenclature of Magnolia subsect. Talauma in Cuba is reviewed. Diagnoses of all taxa are presented with an identification key, nomenclatural information and distribution. Magnolia subsect. Talauma in Cuba comprises three endemic species: Magnolia orbiculata, M. minor and M. oblongifolia. Magnolia orbiculata is the only species that keeps the same limits as in the previous taxonomic treatments of the group, whereas it is not the same for the northeastern Cuban species.

An accurate taxa delimitation, based on a full understanding of evolutionary processes involved in taxa differentiation, can be gained from a combination of ecological, morphological, and molecular approaches. The taxonomy of Magnolia subsect. Talauma in Cuba has long been debated and exclusively based on traditional morphological study of a limited number of individuals. A more accurate description of leaf morphology variation using geometric morphometrics combined with genetic data could bring consistency to taxa delimitation in this group. Leaf samples for the morphological (243) and genetic (461) analyses were collected throughout the entire distribution range. The variability of each taxon was analyzed through multivariate and geometric morphometry, and 21 genetic markers (SSR). The observed leaf morphological variability was higher than previously described. Morphological and genetic classifications were highly congruent in two out of four taxa. Our data brought evidence that Magnolia orbiculata can be considered a true species with very clear genetic and morphological limits. The main taxonomic issues concern the north-eastern Cuban populations of Magnolia subsect. Talauma. The data supported the existence of two clear groups: corresponding mainly to M. minor - M. oblongifolia and T. ophiticola . However, these two groups cannot be considered fully delimited since genetic markers provided evidence of genetic admixture between them. Due to the likely absence of, at least strong, reproductive barriers between these three taxa, we propose therefore to consider them as a species complex.

The genus Ramonda includes three Paleoendemic and Tertiary relict species that survived in refugial habitats of the Balkan Peninsula (R. nathaliae and R. serbica) and the Iberian Peninsula (R. myconi). They are all “resurrection plants,” a rare phenomenon among flowering plants in Europe. Ramonda myconi and R. nathaliae are diploids (2n = 2x = 48), while R. serbica is a hexaploid (2n = 6x = 144). The two Balkan species occur in sympatry in only two localities in eastern Serbia, where tetraploid potential hybrids (2n = 4x = 96) were found. This observation raised questions about the existence of gene flow between the two species and, more generally, about the evolutionary processes shaping their genetic diversity. To address this question, genetic markers (AFLP) and an estimate of genome size variation were used in a much larger sample and at a larger geographic scale than previously. The combination of AFLP markers and genome size results suggested ongoing processes of interspecific and interploidy hybridization in the two sites of sympatry. The data also showed that interspecific gene flow was strictly confined to sympatry. Elsewhere, both Ramonda species were characterized by low genetic diversity within populations and high population differentiation. This is consistent with the fact that the two species are highly fragmented into small and isolated populations, likely a consequence of their postglacial history. Within sympatry, enormous variability in cytotypes was observed, exceeding most reported cases of mixed ploidy in complex plant species (from 2x to >8x). The AFLP profiles of non-canonical ploidy levels indicated a diversity of origin pathways and that backcrosses probably occur between tetraploid interspecific hybrids and parental species. The question arises whether this diversity of cytotypes corresponds to a transient situation. If not, the question arises as to the genetic and ecological mechanisms that allow this diversity to be maintained over time.

The original article was published with missing information in Table 1. The complete Table 1 is now provided: this correction stands to correct the original article