Individual and comparative phylogeography of Rhinanthus angustifolius and Rhinanthus minor in Europe

Drastic environmental changes, such as the climatic oscillations of the Pleistocene, have dramatically influenced the level and spatial organization of species genetic diversity. In Europe, the impact of such environmental alterations on the genetic structure of long-lived plant species is well documented, but little information is available for annual. Therefore, this thesis aimed to establish large scale phylogeographies for annual species, and we focused on the two widespread European species of the annual genus Rhinanthus (Orobanchaceae): R. angustifolius and R. minor. Genetic variation was investigated using of chloroplast DNA (cpDNA) sequences and amplified fragment length polymorphisms (AFLPs) in both species. For R. angustifolius, genetic variation revealed by AFLPs was clearly structured geographically, and yielded various phylogeographic hypotheses similar to what is generally observed for long-lived species. Contrary to AFLPs, the cpDNA variation observed did not show any clear geographic structuring. To explain such incongruities between the patterns revealed by cpDNA and AFLPs, wide-ranging hybridization with the closely related R. minor has been proposed. Confirmation of the importance of hybridization between these species came from the investigation of genetic variation within and among R. minor populations, which revealed an extensive and geographically structured cpDNA haplotype sharing. At the same time, the congruent cpDNA and AFLP patterns found in R. minor indicated that hybridization did not affect the phylogeographic survey of this species and confirmed observation of a local asymmetric introgression toward R. angustifolius. Furthermore, related to these phylogeographic investigations, experimental crossing confirmed the general rule of matrilineal inheritance of the chloroplast genome in Rhinanthus, and preliminaries investigations of the relationship between genetic and morphological variation were conducted.Doctorat en sciences (sciences biologiques) (BIOL 3)--UCL, 201

Inheritance of the chloroplast genome in Rhinanthus angustifolius (Orobanchaceae)

Background and aims – The mode of inheritance of the chloroplast genome is an important factor in studies dealing with population and evolutionary plant biology. In this paper, we aim to determine the chloroplast DNA (cpDNA) inheritance in Rhinanthus angustifolius. Methods – We studied the cpDNA inheritance using PCR-RFLP. One hundred sixty six offspring obtained from controlled crosses between individuals with two distinct chlorotypes were analysed. Key results – All the progeny exhibited the maternal chloroplast genome. The power analysis of the binomial distribution showed that the frequency of paternal transmission of the chloroplast, if any, should not exceed 1.81% (with 95% confidence). This work indicates that maternal inheritance of the chloroplast genome in Rhinanthus angustifolius is a reasonable assumption

Hybridization in annual plants: patterns and dynamics during a four-year study in mixed Rhinanthus populations

Hybridization in annual plants is rare, but their short life cycle provides an excellent opportunity to study the dynamics of hybridization. Hybridization occurs between the annual hemiparasites Rhinanthus minor and Rhinanthus angustifolius (Orobanchaceae). Using flower morphology, Kwak (1980) found a prevalence of hybrids close to R. angustifolius in a single population. We aim to find whether this pattern is also found using genetic markers, whether it is generally occurring in mixed populations, and whether these populations are stable over time. We used species-specific genetic markers to determine the number of individuals in a range of hybrid classes in three mixed populations of different ages during four consecutive years. In the young population, F-1 hybrids were found in the first year and mostly hybrids between R. minor and these F(1)s in the second year, but in the years after that, hybrids close to R. angustifolius became more abundant. We also found this in the two older populations, where hybrids close to R. angustifolius always occurred in higher frequencies than hybrids close to R. minor. Over time, R. angustifolius strongly increased in frequency in two populations. Patterns of marker presence and absence suggested that advanced-generation hybrids are mainly formed by backcrossing with one of the parents, predominantly R. angustifolius whenever its frequency in the population is higher than 15%. The dynamics of mixed populations depend on the ecological conditions that regulate the presence of the two parental species, and introgression into R. angustifolius seems prevalent

How did an annual plant react to Pleistocene glaciations? Postglacial history of Rhinanthus angustifolius in Europe

The impact of climate fluctuations during the Pleistocene on the geographic structure of genetic variation in plant populations is well documented, but there is a lack of studies of annual species at the European scale. The present study aimed to infer the history of the widespread European annual Rhinanthus angustifolius C. C. Gmelin (Orobanchaceae). We explored variation in chloroplast DNA (cpDNA) sequences and amplified fragment length polymorphism (AFLP) in twenty-nine populations covering the entire distribution area of the species. Five AFLP groups were identified, suggesting at least two glacial refugial areas: one area in southwestern Europe and one large eastern area in the Balkan/Caucasus. Recolonization of previously glaciated areas mainly took place from the east of Europe. Despite the difference in life-history traits, the patterns found for the annual R. angustifolius show similarities with those of perennial species in terms of genetic diversity and geographic organization of genetic variation. Although organelle markers have typically been preferred in phylogeographic studies, the cpDNA variation in R. angustifolius did not show any clear geographic structure. The absence of geographic structure in the cpDNA variation may reflect persistence of ancestral polymorphisms or hybridization and introgression with closely-related species. (C) 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 98, 1-13

Dynamic Kinetic Resolution Processes Based on the Switchable Configurational Instability of Allenyl Copper Reagents

International audienceThe configurational instability of allenyl copper reagents is unveiled. An experimental study highlights the crucial role of Li+ and of the reaction temperature in the control of the configurational stability of allenyl copper reagents. A judicious choice of the reaction conditions allows efficient dynamic kinetic resolution processes and gives a one-pot access to homopropargylic alcohols or amines bearing up to four contiguous defined stereogenic centers

An immunohistochemical procedure to detect patients with paraganglioma and phaeochromocytoma with germline SDHB, SDHC, or SDHD gene mutations: a retrospective and prospective analysis.

Contains fulltext : 80017.pdf (publisher's version ) (Closed access)BACKGROUND: Phaeochromocytomas and paragangliomas are neuro-endocrine tumours that occur sporadically and in several hereditary tumour syndromes, including the phaeochromocytoma-paraganglioma syndrome. This syndrome is caused by germline mutations in succinate dehydrogenase B (SDHB), C (SDHC), or D (SDHD) genes. Clinically, the phaeochromocytoma-paraganglioma syndrome is often unrecognised, although 10-30% of apparently sporadic phaeochromocytomas and paragangliomas harbour germline SDH-gene mutations. Despite these figures, the screening of phaeochromocytomas and paragangliomas for mutations in the SDH genes to detect phaeochromocytoma-paraganglioma syndrome is rarely done because of time and financial constraints. We investigated whether SDHB immunohistochemistry could effectively discriminate between SDH-related and non-SDH-related phaeochromocytomas and paragangliomas in large retrospective and prospective tumour series. METHODS: Immunohistochemistry for SDHB was done on 220 tumours. Two retrospective series of 175 phaeochromocytomas and paragangliomas with known germline mutation status for phaeochromocytoma-susceptibility or paraganglioma-susceptibility genes were investigated. Additionally, a prospective series of 45 phaeochromocytomas and paragangliomas was investigated for SDHB immunostaining followed by SDHB, SDHC, and SDHD mutation testing. FINDINGS: SDHB protein expression was absent in all 102 phaeochromocytomas and paragangliomas with an SDHB, SDHC, or SDHD mutation, but was present in all 65 paraganglionic tumours related to multiple endocrine neoplasia type 2, von Hippel-Lindau disease, and neurofibromatosis type 1. 47 (89%) of the 53 phaeochromocytomas and paragangliomas with no syndromic germline mutation showed SDHB expression. The sensitivity and specificity of the SDHB immunohistochemistry to detect the presence of an SDH mutation in the prospective series were 100% (95% CI 87-100) and 84% (60-97), respectively. INTERPRETATION: Phaeochromocytoma-paraganglioma syndrome can be diagnosed reliably by an immunohistochemical procedure. SDHB, SDHC, and SDHD germline mutation testing is indicated only in patients with SDHB-negative tumours. SDHB immunohistochemistry on phaeochromocytomas and paragangliomas could improve the diagnosis of phaeochromocytoma-paraganglioma syndrome. FUNDING: The Netherlands Organisation for Scientific Research, Dutch Cancer Society, Vanderes Foundation, Association pour la Recherche contre le Cancer, Institut National de la Sante et de la Recherche Medicale, and a PHRC grant COMETE 3 for the COMETE network