Distribution, écologie et évolution de l'hyperaccumulation des éléments en traces par Noccaea caerulescens

Noccaea caerulescens (Brassicaceae) is the main hyperaccumulator of Cd, Ni and Zn, candidate for phytoremediation of contaminated soils. The distribution of the species is characterized by a high degree of heterogeneity of environmental factors, especially concerning the soil composition. In addition, significant variations in the hyperaccumulation ability between populations of the species have been observed. Therefore, from a broad sampling in France and its neighboring regions, the aim of this thesis was: i) a better understanding of the ecology of N. caerulescens including soil habitat components, iii) a comparison of the ability of populations to accumulate Cd, Ni and Zn and iii) the assessment of the genetic structure among populations. Our results show that N. caerulescens is widespread in the French mountains and not restricted to the metalliferous sites given the large number of non-metalliferous stations explored. In addition, the prospected stations are characterized by a wide range in the soil composition leading to propose a new classification of N. caerulescens stations. On the accumulation of trace elements in situ, we have shown that the bioavailability of trace elements was not the only factor explaining the observed concentrations in the plant. Moreover, hydroponic cultures highlighted a compromise between carbon allocation and accumulation of trace elements especially in serpentine populations. Finally, the analysis of the neutral genetic structure highlighted three geographic regions highly differentiated, but not consistent with the edaphic typeNoccaea caerulescens est la principale Brassicacée hyperaccumulatrice de Cd, Ni et Zn, candidate pour la phytoremédiation des sols contaminés. La distribution de l'espèce se caractérise par une importante hétérogénéité des facteurs environnementaux, et plus particulièrement en ce qui concerne la nature des sols. En outre, des variations importantes de la capacité d'hyperaccumulation entre les populations de l'espèce ont déjà été observées. Dès lors, à partir d'un vaste échantillonnage en France et ses régions limitrophes, l'objectif de cette thèse était de : i) mieux appréhender l'écologie de N. caerulescens notamment les composantes édaphiques de son habitat, iii) comparer les capacités d'accumulation en Cd, Ni et Zn et, iii) déterminer les relations génétiques entre les populations. Nos résultats montrent que N. caerulescens est largement répandue dans les massifs montagneux et que l'espèce n'est pas inféodée aux sites métallifères vu le nombre de stations en milieu non minier. Par ailleurs, les stations se caractérisent par une très large amplitude des paramètres édaphiques conduisant à proposer une nouvelle classification des stations. Concernant l'accumulation des éléments en traces in situ, nous avons démontré que la biodisponibilité ne permettait pas d'expliquer seule les concentrations observées dans la plante. Par ailleurs, des cultures en hydroponie ont mis en évidences un compromis entre l'allocation du carbone et l'accumulation des éléments en traces en particulier chez les populations sur serpentines. Enfin, l'analyse de la structure génétique neutre a fait ressortir trois zones géographiques fortement différenciées, sans cohérence avec le type de milie

Distribution, ecology and evolution of trace element hyperaccumulation by Noccaea caerulescens

Noccaea caerulescens est la principale Brassicacée hyperaccumulatrice de Cd, Ni et Zn, candidate pour la phytoremédiation des sols contaminés. La distribution de l'espèce se caractérise par une importante hétérogénéité des facteurs environnementaux, et plus particulièrement en ce qui concerne la nature des sols. En outre, des variations importantes de la capacité d'hyperaccumulation entre les populations de l'espèce ont déjà été observées. Dès lors, à partir d'un vaste échantillonnage en France et ses régions limitrophes, l'objectif de cette thèse était de : i) mieux appréhender l'écologie de N. caerulescens notamment les composantes édaphiques de son habitat, iii) comparer les capacités d'accumulation en Cd, Ni et Zn et, iii) déterminer les relations génétiques entre les populations. Nos résultats montrent que N. caerulescens est largement répandue dans les massifs montagneux et que l'espèce n'est pas inféodée aux sites métallifères vu le nombre de stations en milieu non minier. Par ailleurs, les stations se caractérisent par une très large amplitude des paramètres édaphiques conduisant à proposer une nouvelle classification des stations. Concernant l'accumulation des éléments en traces in situ, nous avons démontré que la biodisponibilité ne permettait pas d'expliquer seule les concentrations observées dans la plante. Par ailleurs, des cultures en hydroponie ont mis en évidences un compromis entre l'allocation du carbone et l'accumulation des éléments en traces en particulier chez les populations sur serpentines. Enfin, l'analyse de la structure génétique neutre a fait ressortir trois zones géographiques fortement différenciées, sans cohérence avec le type de milieuNoccaea caerulescens (Brassicaceae) is the main hyperaccumulator of Cd, Ni and Zn, candidate for phytoremediation of contaminated soils. The distribution of the species is characterized by a high degree of heterogeneity of environmental factors, especially concerning the soil composition. In addition, significant variations in the hyperaccumulation ability between populations of the species have been observed. Therefore, from a broad sampling in France and its neighboring regions, the aim of this thesis was: i) a better understanding of the ecology of N. caerulescens including soil habitat components, iii) a comparison of the ability of populations to accumulate Cd, Ni and Zn and iii) the assessment of the genetic structure among populations. Our results show that N. caerulescens is widespread in the French mountains and not restricted to the metalliferous sites given the large number of non-metalliferous stations explored. In addition, the prospected stations are characterized by a wide range in the soil composition leading to propose a new classification of N. caerulescens stations. On the accumulation of trace elements in situ, we have shown that the bioavailability of trace elements was not the only factor explaining the observed concentrations in the plant. Moreover, hydroponic cultures highlighted a compromise between carbon allocation and accumulation of trace elements especially in serpentine populations. Finally, the analysis of the neutral genetic structure highlighted three geographic regions highly differentiated, but not consistent with the edaphic typ

Distribution, écologie et évolution de l'hyperaccumulation des éléments en traces par Noccaea caerulescens

Noccaea caerulescens est la principale Brassicacée hyperaccumulatrice de Cd, Ni et Zn, candidate pour la phytoremédiation des sols contaminés. La distribution de l'espèce se caractérise par une importante hétérogénéité des facteurs environnementaux, et plus particulièrement en ce qui concerne la nature des sols. En outre, des variations importantes de la capacité d'hyperaccumulation entre les populations de l'espèce ont déjà été observées. Dès lors, à partir d'un vaste échantillonnage en France et ses régions limitrophes, l'objectif de cette thèse était de : i) mieux appréhender l'écologie de N. caerulescens notamment les composantes édaphiques de son habitat, iii) comparer les capacités d'accumulation en Cd, Ni et Zn et, iii) déterminer les relations génétiques entre les populations. Nos résultats montrent que N. caerulescens est largement répandue dans les massifs montagneux et que l'espèce n'est pas inféodée aux sites métallifères vu le nombre de stations en milieu non minier. Par ailleurs, les stations se caractérisent par une très large amplitude des paramètres édaphiques conduisant à proposer une nouvelle classification des stations. Concernant l'accumulation des éléments en traces in situ, nous avons démontré que la biodisponibilité ne permettait pas d'expliquer seule les concentrations observées dans la plante. Par ailleurs, des cultures en hydroponie ont mis en évidences un compromis entre l'allocation du carbone et l'accumulation des éléments en traces en particulier chez les populations sur serpentines. Enfin, l'analyse de la structure génétique neutre a fait ressortir trois zones géographiques fortement différenciées, sans cohérence avec le type de milieuNoccaea caerulescens (Brassicaceae) is the main hyperaccumulator of Cd, Ni and Zn, candidate for phytoremediation of contaminated soils. The distribution of the species is characterized by a high degree of heterogeneity of environmental factors, especially concerning the soil composition. In addition, significant variations in the hyperaccumulation ability between populations of the species have been observed. Therefore, from a broad sampling in France and its neighboring regions, the aim of this thesis was: i) a better understanding of the ecology of N. caerulescens including soil habitat components, iii) a comparison of the ability of populations to accumulate Cd, Ni and Zn and iii) the assessment of the genetic structure among populations. Our results show that N. caerulescens is widespread in the French mountains and not restricted to the metalliferous sites given the large number of non-metalliferous stations explored. In addition, the prospected stations are characterized by a wide range in the soil composition leading to propose a new classification of N. caerulescens stations. On the accumulation of trace elements in situ, we have shown that the bioavailability of trace elements was not the only factor explaining the observed concentrations in the plant. Moreover, hydroponic cultures highlighted a compromise between carbon allocation and accumulation of trace elements especially in serpentine populations. Finally, the analysis of the neutral genetic structure highlighted three geographic regions highly differentiated, but not consistent with the edaphic typeNANCY-INPL-Bib. électronique (545479901) / SudocSudocFranceF

Variation of trace metal accumulation, major nutrient uptake and growth parameters and their correlations in 22 populations of Noccaea caerulescens

International audienc

Mycorrhizae and plant metal uptake

<p>File “Dietterich et al myco-metal data for figshare 170521.csv” contains data on plant and soil metal concentrations and plant root colonization by arbuscular mycorrhizal fungi (AMF). Samples were collected in 2012 in portions of the Palmerton Zinc Superfund Site (Palmerton, PA, USA) owned and managed by the Lehigh Gap Nature or the National Park Service (Dietterich et al. <i>in press</i>). </p> <p> </p> <p>File “Dietterich et al myco-metal metadata for figshare 170521.csv” contains definitions of column headings for the above dataset. </p> <p> </p> <p>Reference:</p> <p>Dietterich, L. H., Gonneau, C. and Casper, B. B. <i>in press</i>. Arbuscular mycorrhizal colonization has little consequence for plant heavy metal uptake in contaminated field soils. <i>Ecological Applications</i> doi:10.1002/eap.1573</p

The role of epiphytism in architecture and evolutionary constraint within mycorrhizal networks of tropical orchids

International audienceCharacterizing the architecture of bipartite networks is increasingly used as a framework to study biotic interactions within their ecological context and to assess the extent to which evolutionary constraint shape them. Orchid mycorrhizal symbioses are particularly interesting as they are viewed as more beneficial for plants than for fungi, a situation expected to result in an asymmetry of biological constraint. This study addressed the architecture and phylogenetic constraint in these associations in tropical context. We identified a bipartite network including 73 orchid species and 95 taxonomic units of mycorrhizal fungi across the natural habitats of Reunion Island. Unlike some recent evidence for nestedness in mycorrhizal symbioses, we found a highly modular architecture that largely reflected an ecological barrier between epiphytic and terrestrial subnetworks. By testing for phylogenetic signal, the overall signal was stronger for both partners in the epiphytic subnetwork. Moreover, in the subnetwork of epiphytic angraecoid orchids, the signal in orchid phylogeny was stronger than the signal in fungal phylogeny. Epiphytic associations are therefore more conservative and may co-evolve more than terrestrial ones. We suggest that such tighter phylogenetic specialization may have been driven by stressful life conditions in the epiphytic niches. In addition to paralleling recent insights into mycorrhizal networks, this study furthermore provides support for epiphytism as a major factor affecting ecological assemblage and evolutionary constraint in tropical mycorrhizal symbioses

Characterization and Multiplexing of 21 Microsatellite Markers for the Herb Noccaea caerulescens (Brassicaceae)

Premise of the study: Multiplexed microsatellite markers were developed for population genetic studies in the pseudometallophyteNoccaea caerulescens (Brassicaceae), a model species to investigate metal tolerance and hyperaccumulation in higherplants.• Methods and Results: Microsatellite loci were isolated through pyrosequencing of an enriched DNA library. Three multiplexescombining four previously published and 17 newly designed markers were developed. The new markers were screened inmetallicolous and nonmetallicolous populations from southern France. The total number of alleles per locus ranged from fi veto 18. The observed heterozygosity per locus and per population ranged from 0 to 0.83, and expected heterozygosity rangedfrom 0 to 0.89.• Conclusions: The investigated loci showed reasonable to high levels of polymorphism at the regional scale. The multiplex setshould be helpful in investigating genetic diversity, population structure, and demographic history in N. caerulescens at variousspatial scales

Differential elemental uptake in three pseudo-metallophyte C4 grasses in situ in the eastern USA

Background and aimsElemental uptake in serpentine floras in eastern North America is largely unknown. The objective of this study was to determine major and trace element concentrations in soil and leaves of three native pseudo-metallophyte C4 grasses in situ at five sites with three very different soil types, including three serpentine sites, in eastern USA.MethodsPseudo-total and extractible concentrations of 15 elements were measured and correlated from the soils and leaves of three species at the five sites.ResultsElement concentrations in soils of pseudo-metallophytes varied up to five orders of magnitude. Soils from metalliferous sites exhibited higher concentrations of their characteristic elements than non-metalliferous. In metallicolous populations, elemental concentrations depended on the element. Concentrations of major elements (Ca, Mg, K) in leaves were lower than typical toxicity thresholds, whereas concentrations of Zn were higher.ConclusionsIn grasses, species can maintain relatively low metal concentrations in their leaves even when soil concentrations are richer. However, in highly Zn-contaminated soil, we found evidence of a threshold concentration above which Zn uptake increases drastically. Finally, absence of main characteristics of serpentine soil at one site indicated the importance of soil survey and restoration to maintain serpentinophytes communities and avoid soil encroachment

Design and validation of sixteen single nucleotide polymorphism to investigate plastid DNA sequence variation in Noccaea caerulescens (Brassicaceae)

Noccaea caerulescens :belong to the legally protected vegetation of metalliferous sites in Europe. It is also a model species for the study of metal-related traits. To improve the understanding of the evolutionary history of the species, 32 single nucleotide polymorphism (SNP) were discovered in several intragenic spacers of the chloroplastic genome by Sanger Sequencing from a representative set of populations throughout Europe. From these 32 SNPs 16 SNP were validated by KASPar assay, which provided a cost-effective set of polymorphisms to be used in population genetic and phylogeography studies of this plant species and close relatives.SCOPUS: ar.jinfo:eu-repo/semantics/publishe