About
253
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Introduction
I am a population geneticist and evolutionary biologist. I have been working mostly with forest trees. Using these organisms as models, I try to identify general processes that shape biodiversity at different timescales, using both empirical approaches (typically relying on the use of molecular markers and methods of genetic data analysis) and simulations, mostly in collaboration. I currently work on tree pollination ecology and evolution.
Additional affiliations
January 2003 - present
January 1993 - December 2002
Publications
Publications (253)
Without reliable pollination services, it is not possible to have high-yielding orchards. In chestnut, results obtained in recent years call into question traditional orchard conception. To design well-pollinated orchards, it is important to include enough genetic diversity to ensure effective cross-fertilization. Traditional use of as few cultivar...
How are chestnuts pollinated? By wind, insects, or both? For almost 150 years, this question has been in the air. The huge production of tiny pollen grains transported by wind over long distances seems to point towards wind pollination. However, the brightly coloured flowers, the strong spermatic odour emitted by flowering trees, and the sticky pol...
Premise
Gynodioecy is a rare sexual system in which two genders ( sensu Lloyd, 1980), cosexuals and females, coexist. To survive, female plants must compensate for their lack of siring capacity and male attractiveness. In European chestnut ( Castanea sativa ), an outcrossing tree, self‐pollination reduces fruit set in cosexual individuals because o...
Key message
In arboriculture, the number and diversity of pollen donors can have a major impact on fruit production. We studied pollination insurance in hybrid chestnut orchards ( C. sativa × C. crenata ) provided by nearby wild European chestnuts ( C. sativa ) in southwestern France. Most fruits were sired by hybrid pollenizers rather than by wild...
Key message
Appropriate silvicultural practices combined with the use of resistant Central European provenances can reduce the prevalence of larch canker caused by Lachnellula willkommii (R. Hartig) Dennis, a major disease affecting larch plantations in France. However, cascading translocations have resulted in frequent admixture in European larch...
Premise:
In flowering plants, intersexual mating facilitation has been left largely underexplored. Duodichogamy is a rare flowering system designating plants that flower in the sequence male-female-male. We study the adaptive advantages of this flowering system using chestnuts (Castanea spp., Fagaceae) as models. These insect-pollinated trees prod...
Most seed plants produce both pollen and ovules. In principle, pollen export could interfere with pollen import, resulting in ovule loss and reduced fruit set. Evidence for such interference exists under experimental settings but its importance under natural conditions is unknown. To test for sexual interference in nature, it is necessary to study...
A bstract
Background and Aim
In gynodioecious plants, male-sterile individuals must have a female advantage to coexist with bisexual individuals. In European chestnuts, characterized by a form of late-acting self-incompatibility, male-fertile trees produce large amounts of pollen when female flowers are receptive, resulting in abundant self-pollin...
Ecological character displacement (ECD) refers to a pattern of increased divergence at sites where species ranges overlap caused by competition for resources. Although ECD is believed to be common, there are few in‐depth studies that clearly establish its existence, especially in plants.
Thus, we have compared leaf traits in allopatric and sympatri...
Pollination is a key step of plant reproduction, allowing individual plants to produce offspring as father, mother or both. However, few studies exist that consider together male and female pollination success. This implies studying both mating system, through paternity analyses, and seed set, by measuring the percentage of flowers giving a seed. S...
We have performed new insect-exclusion experiments to test if chestnuts are insect-pollinated, as proposed in an earlier study. We used double rather than simple nets to ensure that erect styles do not emerge outside of the nets while allowing most airborne pollen to penetrate. Our findings indicate that ≥94% of chestnut flowers are pollinated by i...
Key message
Pollination is a key step for fruit production. To provide a tool for future in-depth analysis of pollination in chestnut, we describe in detail a chestnut orchard (location, genotype, phenotype and seed-set of all trees).
Context
Chestnuts, which are insect-pollinated trees, have been massively planted around the world for nut product...
To better study and manage chestnut trees and species, we identified nuclear single nucleotide polymorphism (SNP) markers using restriction-associated DNA sequencing. Out of 343 loci tested, 68 SNP markers were selected that withhold stringent quality criteria such as quasi-systematic amplification across species and Mendelian segregation in both p...
The software and the manual have been updated in June 2021:
https://www.thuenen.de/de/fg/software/
To better study and manage chestnut trees and species, we identified nuclear single nucleotide polymorphism (SNP) markers using restriction-associated DNA sequencing. Out of 343 loci tested, 68 SNP markers were selected that withhold stringent quality criteria such as quasi-systematic amplification across species and Mendelian segregation in both p...
Wind, insects, or both? The pollination mode of chestnuts, an important genus of nut-producing forest trees of the Fagaceae family, is still unclear. We revisit this old question using an integrated approach, focusing on cultivated Castanea sativa trees and hybrids in South-western France. We first conducted a large-scale insect isolation experimen...
Chestnuts (Castanea spp.) are ecologically and economically important forest and fruit trees. They are cultivated for their nutritious nuts. To select varieties to be cultivated in chestnut orchards, their phenology needs to be considered. In this work, we adapt the international BBCH system to chestnuts by building on an existing phenological scal...
Sixty years from the first disease description, a novel badnavirus associated with chestnut mosaic disease
Although the chestnut mosaic disease (ChMD) was described several decades ago, its etiology is still not elucidated. Here, using classical approaches in combination with high throughput sequencing (HTS) techniques, we identify a novel Badnavirus that is a strong etiological candidate for ChMD. Two disease sources from Italy and France were submitte...
Chestnut species have large ecological, cultural and economic importance. Developing genetic markers for these species is of interest for conservation, breeding or evolutionary studies. We designed 192 primer pairs targeting microsatellites detected in the Castanea mollissima reference genome and tested them on C. sativa and C. crenata. We PCR ampl...
One of Anthropocene's most daunting challenges for conservation biology is habitat extinction, caused by rapid global change. Tree diversity has persisted through previous episodes of rapid change, even global extinctions. Given the pace of current change, our management of extant diversity needs to facilitate and even enhance the natural ability o...
• We investigate chloroplast DNA variation in a hyperdiverse community of tropical rainforest trees in French Guiana, focusing on patterns of intraspecific and interspecific variation. We test whether a species genetic diversity is higher when it has congeners in the community with which it can exchange genes and if shared haplotypes are more frequ...
Quercus magnoliifolia and Q. resinosa are two Mexican white oak species that have been taxonomically reported to exhibit morphological similarities and possible hybridization. The objective of this study was to compare the variation in Q. magnoliifolia and Q. resinosa throughout their distribution range to identify the degree of species differentia...
Persistence of natural populations during periods of climate change is likely to depend on migration (range shifts) or adaptation. These responses were traditionally considered discrete processes and conceptually divided into the realms of ecology and evolution. In a milestone paper, Davis and Shaw (2001) argued that the interplay of adaptation and...
Aims Comparisons of climate envelopes among species have shown that niche conservatism tends to break down over time. Here, we use the Asian tree genus Platycarya (Juglandaceae) as a case study to test this tendency at relatively short timescales in a single lineage. This, together with a reanalysis of the extant literature, should help evaluate pr...
Subtropical East Asia harbours a large plant diversity that is often attributed to allopatric speciation in this topographically complex region characterized by a relative climate stability. Here, we use observations of Platycarya, a widespread subtropical Asian tree genus, to explore the consequences of past climate stability on species’ evolution...
Hybridization is a key evolutionary process with major consequences for conservation and speciation. However, sexual barriers interact with the local context to determine hybridization rates in a way that is still poorly explored. For instance, in the context of an expanding or introduced plant population, where a few individuals are isolated in po...
Spring shoot phenology is an adaptive trait highly responsive to climatic conditions that influences plant growth and development, as well as plant-herbivore interactions. We investigated if the geographic origin of cork oak influenced spring shoot phenology (timing of budburst) and if the variation among provenances (advances and/or delays) had co...
Retrospective studies focussing on forest dynamics using fossil and genetic data can provide important keys to prepare forests for the future. In this study we analyse the impact of past climate and anthropogenic changes on Larix decidua Mill. (European larch) populations based on a new range-wide fossil compilation encompassing the last 130 ka and...
Disruption of species interactions is a key issue in climate change biology. Interactions involving forest trees may be particularly vulnerable due to evolutionary rate limitations imposed by long generation times. One mitigation strategy for such impacts is Climate matching – the augmentation of local native tree populations by input from non-loca...
In contrast to biological invasions, translocations of individuals within a species range are understudied, due to difficulties in systematically detecting them. This results in limited knowledge about the corresponding processes and uncertainties regarding the status of ex-tant populations. European larch, a forest tree whose fragmented native dis...
Despite their critical importance for understanding the local effects of global climate change on biodiversity, glacial microrefugia are not well studied because they are difficult to detect by using classical palaeoecological or population genetics approaches. We used soil macrofossil charcoal analysis to uncover the presence of cryptic glacial re...
Reproductive strategies of closely related species distributed along successional gradients should differ as a consequence of the trade-off between competition and colonization abilities. We compared male reproductive strategies of Quercus robur and Q. petraea, two partly interfertile European oak species with different successional status. In the...
Extant rear-edge populations located in former glacial refugia remain understudied despite their high conservation value. These populations should have experienced strong genetic drift due to their small size and long isolation. Moreover, the prolonged action of isolation by distance in refugial areas should result in stronger regional spatial gene...
Numerous plant species are shifting their range polewards in response to ongoing climate change. Range shifts typically involve the repeated establishment and growth of leading-edge populations well ahead of the main species range. How these populations recover from founder events and associated diversity loss remains poorly understood. To help fil...
Although interfertility is the key criterion upon which Mayr's biological species concept is based, it has never been applied directly to delimit species under natural conditions. Our study fills this gap. We used the interfertility criterion to delimit two closely related oak species in a forest stand by analyzing the network of natural mating eve...
The Fagaceae family includes over 1000 tree and shrub species such as the familiar oaks (genus Quercus), beeches (Fagus) and chestnuts (Castanea), which are widespread in the northern hemisphere. However, the family also includes related genera such as Castanopsis and Lithocarpus that comprise hundreds of species in Asia, whereas the southern beech...
Project no. 284181 - Trees4Future - Designing Trees for the Future
This report will specify which methods have already been tried successfully in different labs, and where researchers and practitioners see the greatest needs for new marker development.
http://www.trees4future.eu/uploads/t4fdeliverables/284181_T4F_D7.1_Methods_identification_web.pd...
Loci considered to be under selection are generally avoided in attempts to infer past demographic processes as they do not fit neutral model assumptions. However, opportunities to better reconstruct some aspects of past demography might thus be missed. Here we examined genetic differentiation between two sympatric European oak species with contrast...
Natural hybridization is attracting much interest in modern speciation and conservation biology studies, but the underlying mechanisms remain poorly understood. In particular, it is unclear why environmental changes often increase hybridization rates. To study this question, we surveyed mating events in a mixed oak stand and developed a spatially e...
Although interfertility is the key criterion upon which Mayr's biological species concept is based, it has never been applied directly to delimit species under natural conditions. Our study fills this gap. We used the interfertility criterion to delimit two closely related oak species in a forest stand by analyzing the network of natural mating eve...
Genome scans are increasingly used to study ecological speciation, providing a useful genome-wide perspective on divergent selection in the presence of gene flow. Here, we compare current approaches to detect footprints of divergent selection in closely related species. We analyzed 192 individuals from two interfertile European temperate oak specie...
We have designed two highly polymorphic microsatellite multiplexes for Larix decidua Mill (European larch), a coniferous tree species with a fragmented distribution across Europe. The multiplexes combine microsatellites previously designed for the sister species L. kaempferi and newly identified microsatellites obtained by pyrosequencing of an enri...
European beech (Fagus sylvatica L.) is one of the economically most important broadleaved tree species in Europe and has become a model for studying climate change effects on forests. Multiplex PCR of microsatellites is a fast and cost-effective technique allowing high-throughput genotyping. Here we present the procedure used to develop two multipl...
Studying geographic variation in the rate of hybridization between closely related species could provide a useful window on the evolution of reproductive isolation. Reinforcement theory predicts greater prezygotic isolation in areas of prolonged contact between recently diverged species than in areas of recent contact, which implies that old contac...
A recent model has shown that, during range expansion of one species in a territory already occupied by a related species, introgression should take place preferentially from the resident species towards the invading species and genome components experiencing low rates of gene flow should introgress more readily than those experiencing high rates o...
Microsatellites have been popular molecular markers ever since their advent in the late eighties. Despite growing competition from new genotyping and sequencing techniques, the use of these versatile and cost-effective markers continues to increase, boosted by successive technical advances. First, methods for multiplexing PCR have considerably impr...
Multiplex PCR is a fast and cost-effective technique allowing increased genotyping throughput of microsatellites. We developed two multiplexes for Quercus petraea and Q. robur, a 12-plex of EST-SSRs (eSSRs) and an 8-plex of genomic SSRs (gSSRs). We studied the origin of allele calling errors at the human reader and software levels. We showed that t...
An official journal of the Genetics Society, Heredity publishes high-quality articles describing original research and theoretical insights in all areas of genetics. Research papers are complimented by News & Commentary articles and reviews, keeping researchers and students abreast of hot topics in the field.
Distribution of per-locus interspecific FST values against heterozygosity in each study site.
(TIF)
Background
The species status of two closely related Chinese oaks, Quercus liaotungensis and Q. mongolica, has been called into question. The objective of this study was to investigate the species status and to estimate the degree of introgression between the two taxa using different approaches.
Methodology/Principal Findings
Using SSR (simple seq...
In heterogeneous environments, sex-biased dispersal could lead to environmental adaptive parental effects, with offspring selected to perform in the same way as the parent dispersing least, because this parent is more likely to be locally adapted. We investigate this hypothesis by simulating varying levels of sex-biased dispersal in a patchy enviro...
There is growing interest in estimating rates of evolutionary change, motivated by the ongoing environmental change (Gingerich 2001; Stockwell et al. 2003; Carroll et al. 2007). Particular concerns have been raised about forest trees, which are thought to be less able to adapt to these rapid changes due to their long generation time (Reich&Oleksyn...
