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Besnard Guillaume


CR1 - CNRS (HDR since 2009)

Tel. 0 (+33) 5 61 55 85 45

Icone contact Email

Main research topics

  • Biogeography of the olive tree and relatives

For more than 20 years, I worked on the olive phylogeography with the main objectives to reconstruct past and recent histories of wild olive populations in order to give new insights on the origins of the cultivated Mediterranean olive, the population dynamic of a saharan subspecies, and the origins of invasive populations in Australia. I’m also interested in the ecology of the olive domestication and invasion. More recently, I started a new projet on the biogeography of the olive family (Oleaceae), with new sequencing approaches, particularly on herbarium specimens from remote areas (including an extinct genus).

  • Multiple evolution of the C4 photosythtic trait in Poales

I’m interested by the evolution of adaptive traits, and particularly multiple evolutions of the C4 photosynthesis in Poales. Using a phylogenomic approach, I study the evolution of C4 genes and the positive selection following their recruitment for the new function. The identification of C3 lineages sister to large C4 clades is also part of my work, in particular with the analysis of old herbarium specimens of rare species.

  • Diverisfication of the Malagasy flora

I’m investigating the evolutionary history of Madagascar lineages in order to elucidate the radiation of clades belonging to the Oleaceae and Poaceae families. Based on the diversification of C4 grass lineages, the origin of open habitats in Madagascar is currently addressed. I also work on the impact of habitat fragmentation on the population dynamic of forest and savanna trees.

Main publications (since 2007)

Besnard G, Terral JF, Cornille A (2018) On the origins and domestication of the olive : a review and perspectives. Annals of Botany 121 : doi:10.1093/aob/mcx145.

Piot A, Hackel J, Christin PA, Besnard G (2018) One third of the plastid genes evolved under positive selection in PACMAD grasses. Planta 147 : doi:10.1007/s00425-017-2781-x.

Gryta H, Van de Paer C, Manzi S, Holota H, Roy M, Besnard G (2017) Genome skimming and plastid microsatellite profiling of alder trees (Alnus spp., Betulaceae) : phylogenetic and phylogeographical prospects. Tree Genetics & Genomes 13 : sous presse.

Dunning L, Liabot AL, Olofsson JK, Smith EK, Vorontsova MS, Besnard G, Simpson KJ, Lundgren MR, Addicott E, Handasyde T, Gallagher RV, Chu Y, Pennington RT, Christin PA, Lehmann CER (2017) The recent and rapid spread of Themeda triandra. Botany Letters 164 : doi:10.1080/23818107.2017.1391120.

Clément Y, Gautier S, Holtz Y, Homa F, Pointet S, Contreras S, Nabholz B, Sabot F, Sauné L, Ardisson M, Bacilieri R, Besnard G, De Bellis F, Fouet O, Jourda C, Khadari B, Lanaud C, Leroy T, Pot D, Sauvage C, Scarcelli N, Tregear J, Vigouroux Y, Yahiaoui N, Ruiz M, Santoni S, Labouisse JP, Pham JL, David J, Glémin S (2017) Evolutionary forces affecting synonymous variations in plant genomes. PLoS Genetics 13 : e1006799.

Minaya* M, Hackel* J, Namaganda M, Brochmann C, Vorontsova MS, Besnard G, Catalán P (2017) Contrasting dispersal histories of broad- and fine-leaved temperate Loliinae grasses : range expansion, founder events, and the roles of distance and barriers. Journal of Biogeography 44 : 1980-1993.

Mensous* M, Van de Paer* C, Manzi S, Bouchez O, Baali-Cherif D, Besnard G (2017) Diversity and evolution of plastomes in Saharan mimosoids : potential use for phylogenetic and population genetic studies. Tree Genetics & Genomes 13 : 48.

Silva C, Besnard G, Piot A, Razanatsoa J, Oliveira RP, Vorontsova MS (2017) Museomics resolve the systematics of an endangered grass lineage endemic to NW Madagascar. Annals of Botany 119 : 339-351.

Ali N, Tavoillot J, Besnard G, et al. (2017) How anthropogenic changes may affect soil-borne parasite diversity ? Plant-parasitic nematode communities associated with olive trees in Morocco as a case study. BMC Ecology 17 : 4.

Van de Paer C, Hong-Wa C, Jeziorski C, Besnard G (2016) Mitogenomics of Hesperelaea, an extinct genus of Oleaceae. Gene 594 : 197-202.

Olofsson* JK, Bianconi* M, Besnard G, Dunning LT, Lundgren MR, Holota H, Vorontsova MS, Hidalgo O, Leitch IJ, Nosil P, Osborne CP, Christin PA (2016) Genome biogeography reveals the intraspecific spread of adaptive mutations for a complex trait. Molecular Ecology 25 : 6107-6123.

Besnard G, Cuneo P (2016) An ecological and evolutionary perspective on the parallel invasion of two cross-compatible trees. AoB Plants 8 : plw056.

Vorontsova MS, Besnard G, Forest F, Malakasi P, Moat J, Clayton WD, Ficinski P, Savva GM, Nanjarisoa OP, Razanatsoa J, Randriatsara FO, Kimeu JM, Luke WR, Kayombo C, Linder HP (2016) Madagascar’s grasses and grasslands : anthropogenic or natural ? Proceedings of the Royal Society, London, Series B-Biological Sciences 283 : 20152262.

Besnard G, Rubio de Casas (2016) Single vs multiple independent olive domestications : the jury is (still) out. New Phytologist 209 : 466-470.

Besnard G, Bertrand JAM, Delahaie B, Bourgeois YXC, Lhuillier E, Thébaud C (2016) Valuing museum specimens : high-throughput DNA sequencing on historical collections of New Guinea crowned pigeons (Goura). Biological journal of the Linnean Society 117 : 71-82.

Zedane L, Hong-Wa C, Murienne J, Jeziorski C, Baldwin BG, Besnard G (2016) Museomics illuminate the history of an extinct, paleoendemic plant lineage (Hesperelaea, Oleaceae) known from an 1875 collection from Guadalupe Island, Mexico. Biological journal of the Linnean Society 117 : 44-57.

Lundgren MR, Besnard G, Ripley BS, Lehmann CE, Chatelet DS, Kynast RG, Namaganda M, Vorontsova MS, Hall RC, Elia J, Osborne CP, Christin PA (2015) Photosynthetic innovation broadens the niche within a single species. Ecology Letters 18 : 1021-1029.

Cornuault J, Khimoun A, Cuneo P, Besnard G (2015) Spatial segregation and realized niche shift during the parallel invasion of two olive subspecies in south-eastern Australia. Journal of Biogeography 42 : 1930-1941.

Besnard G, Christin PA, Malé PJ, Lhuillier E, Lauzeral C, Coissac E, Vorontsova MS (2014) From museums to genomics : old herbarium specimens shed light on a C3 to C4 transition. Journal of Experimental Botany 65 : 6711-6721.

Besnard G, Jühling F, Chapuis E, Zedane L, Lhuillier E, Mateille T, Bellafiore S (2014) Fast assembly of the mitochondrial genome of a plant parasitic nematode (Meloidogyne graminicola) using next generation sequencing. Comptes Rendus ‒ Biologies 337 : 295-301.

Besnard G, El Bakkali A (2014) Sequence analysis of single-copy genes in two wild olive subspecies (Olea europaea L.) : nucleotide diversity and putative use for testing admixture. Genome 57 : 145-153.

Malé PJ, Bardon L, Besnard G, Coissac E, Delsuc F, Engel J, Lhuillier E, Scotti-Saintagne C, Tinaut A, Chave J (2014) Genome skimming by shotgun sequencing helps resolve the phylogeny of a pantropical tree family. Molecular Ecology Resources 14 : 966-975.

Hong-Wa C, Besnard G (2014) Diversification and species limits in the Madagascar olive. Botanical Journal of the Linnean Society 174 : 141-161.

Besnard* G, Dupuy* J, Larter M, Cuneo P, Cooke D, Chikhi L (2014) History of the invasive African olive tree in Australia and Hawaii : evidence for sequential bottlenecks and hybridization with the Mediterranean olive. Evolutionary Applications 7 : 195-211.

Besnard* G, El Bakkali* A, Haouane H, Baali-Cherif D, Moukhli A, Khadari B (2013) Population genetics of Mediterranean and Saharan olives : geographic patterns of differentiation and evidence for early generations of admixture. Annals of Botany 112 : 1293-1302.

Besnard G, Christin PA, Malé PJ, Coissac E, Ralimanana H, Vorontsova MS (2013) Phylogenomics and taxonomy of Lecomtelleae (Poaceae), an isolated panicoid lineage from Madagascar. Annals of Botany 112 : 1057-1066.

Hong-Wa C, Besnard G (2013) Intricate patterns of phylogenetic relationships in the olive family as inferred from multi-locus plastid and nuclear DNA sequence analyses : a close-up on Chionanthus and Noronhia (Oleaceae). Molecular Phylogenetics and Evolution 67 : 367-378.

Besnard G, Khadari B, Navascués M, Fernández-Mazuecos M, El Bakkali A, Arrigo N, Baali-Cherif D, Brunini-Bronzini de Caraffa V, Santoni S, Vargas P, Savolainen V (2013) The complex history of the olive tree : from Late Quaternary diversification of Mediterranean lineages to primary domestication in the northern Levant. Proceedings of the Royal Society, London, Series B-Biological Sciences 280 : 20122833.

Christin PA, Osborne CP, Chatelet DS, Columbus TJ, Besnard G, Hodkinson TR, Vorontsova M, Edwards EJ (2013) Anatomical enablers and the evolution of C4 photosynthesis in grasses. Proceedings of the National Academy of Sciences, USA 110 : 1381-1386.

Pérez-Jiménez M, Besnard G, Dorado G, Hernández P (2013) Varietal tracing of virgin olive oils based on plastid DNA variation profiling. PLoS ONE 8 : e70507.

GPWG II (2012) New grass phylogeny resolves deep evolutionary relationships and discovers C4 origins. New Phytologist 193 : 304-312.

Kaniewski D, Van Campo E, Boiy T, Terral JF, Khadari B, Besnard G (2012) Primary domestication and early uses of the emblematic olive tree : palaeobotanical, historical and molecular evidence from the Middle East. Biological Reviews 87 : 885-899.

Christin PA, Edwards EJ, Besnard G, Boxall SF, Gregory R, Kellogg EA, Hartwell J, Osborne CP (2012) Adaptive evolution of C4 photosynthesis through recurrent lateral gene transfer. Current Biology 22 : 445-449

Christin PA, Besnard G, Edwards EJ, Salamin N (2012) Effect of genetic convergence on phylogenetic inference. Molecular Phylogenetics and Evolution 62 : 921-927.

Besnard G, Hernandez P, Khadari B, Dorado G, Savolainen V (2011) Genomic profiling of plastid DNA variation in the Mediterranean olive tree. BMC Plant Biology 11 : 80.

Santos AMC, Besnard G, Quick DLJ (2011) Applying barcoding for the study of geographical variation in host-parasitoid interactions. Molecular Ecology Resources 11 : 46-59.

Christin PA, Weinreich DM, Besnard G (2010) Causes and evolutionary significance of genetic convergence. Trends in Genetics 26 : 400-405.

Pairon M, Petitpierre B, Broennimann O, Guisan A, Campbell M, Baret P, Jacquemart AL, Besnard G (2010) Multiple introductions boosted genetic diversity in the invasive range of Black Cherry (Prunus serotina, Rosaceae). Annals of Botany 105 : 891-903.

Besnard G, Muasya AM, Russier F, Roalson EH, Salamin N, Christin PA (2009) Phylogenomics of C4 photosynthesis in sedges (Cyperaceae) : multiple appearances and genetic convergence. Molecular Biology and Evolution 26 : 1909-1919.

Besnard G, Basic N, Christin PA, Savova-Bianchi D, Galland N (2009) Thlaspi caerulescens (Brassicaceae) population genetics in western Switzerland : Is the genetic structure affected by natural variation of soil heavy metal concentrations ? New Phytologist 181 : 974-984.

Besnard* G, Rubio de Casas* R, Christin PA, Vargas P (2009) Phylogenetics of Olea (Oleaceae) based on plastid and nuclear ribosomal DNA sequences : Tertiary climatic shifts and lineage differentiation times. Annals of Botany 104 : 143-160.

Christin PA, Petitpierre B, Salamin N, Büchi L, Besnard G (2009) Evolution of C4-related phosphoenolpyruvate carboxykinase in grasses, from genotype to phenotype. Molecular Biology and Evolution 26 : 357-365.

Christin PA, Salamin N, Kellogg EA, Vicentini A, Besnard G (2009) Integrating phylogeny into studies of C4 variation in the grasses. Plant Physiology 149 : 82-87.

Henry P, Le Lay G, Goudet J, Guisan A, Jahadová Š, Besnard G (2009) Reduced genetic diversity, increased isolation and multiple introductions of invasive Giant Hogweed in the western Swiss Alps. Molecular Ecology 18 : 2819-2831.

Christin PA, Besnard G (2009) Two independent C4 origins in Aristidoideae (Poaceae) revealed by the recruitment of distinct phosphoenolpyruvate carboxylase genes. American Journal of Botany 96 : 2234-2239.

Christin PA, Samaritani E, Petitpierre B, Salamin N, Besnard G (2009) Evolutionary insights on C4 photosynthetic biochemical subtypes in grasses from genomics and phylogenetics. Genome Biology and Evolution 1 : 221-230.

Christin PA, Salamin N, Muasya AM, Roalson EH, Russier F, Besnard G (2008) Evolutionary switch and genetic convergence on rbcL following the evolution of C4 photosynthesis. Molecular Biology and Evolution 25 : 2361-2368.

Besnard G, Garcia-Verdugo C, De Casas RR, Treier UA, Galland N, Vargas P (2008) Polyploidy in the olive complex (Olea europaea) : evidence from flow cytometry and nuclear microsatellite analyses. Annals of Botany 101 : 25-30.

Christin PA, Besnard G, Samaritani E, Duvall MR, Hodkinson TR, Savolainen V, Salamin N (2008) Oligocene CO2 decline promoted C4 photosynthesis in grasses. Current Biology 18 : 37-43.

Besnard G, Rubio de Casas R, Vargas P (2007) Plastid and nuclear DNA polymorphism reveals historical processes of isolation and reticulation in the olive tree complex (Olea europaea L.). Journal of Biogeography 34 : 736-752.

Christin PA, Salamin N, Savolainen V, Duvall MR, Besnard G (2007) C4 photosynthesis evolved in grasses via parallel adaptive genetic changes. Current Biology 17 : 1241-1247.

Besnard G, Henry P, Wille L, Cooke D, Chapuis E (2007) On the origin of the invasive olives (Olea europaea L., Oleaceae). Heredity 99 : 608-619.

Besnard G, Christin PA, Baali-Cherif D, Bouguedoura N, Anthelme F (2007) Spatial genetic structure in the Laperrine’s olive (Olea europaea subsp. laperrinei), a long-living tree from central-Saharan mountains. Heredity 99 : 649-657.

Parisod C, Besnard G (2007) Glacial in situ survival in the Western Alps and polytopic autopolyploidy in Biscutella laevigata L. (Brassicaceae). Molecular Ecology 16 : 2755-2767.