Biology subjects

BARLOY, D. H.

Publications and source records attributed to BARLOY, D. H..

3 recordsLinked to original sources

bioRxiv2026

First draft genome of the decaploid species, Ludwigiagrandiflora subsp. hexapetala, validated through geneexpression

Invasive species are one of the biggest drivers of species extinction. Ludwigia grandiflora subsp. hexapetala (Lgh) is widely invasive in aquatic ecosystems of Europe, North America, and Japan, and also colonizes emergent freshwater soils, but limited genomic data constrain studies of its invasiveness. Here, we report a draft genome assembly of Lgh, with a total length of 1.487 Gb, in agreement with the genome size estimated by flow cytometry, despite high fragmentation (111,219 contigs; N50 = 13.5 kb) and low sequencing depth (6.5x Illumina, 1.6x Nanopore). In addition, an analysis combining homology and expression data identified 139,095 protein-coding genes. Moreover, several indicators suggest that the observed fragmentation is largely attributable to unassembled repetitive regions. Thus, despite these limitations, this assembly represents the first genome in the Ludwigioideae subfamily and constitutes a valuable resource for gene discovery, functional genomics, phylogenetic reconstruction, and evolutionary analyses across the Onagraceae family.

genomics↗

bioRxiv2025

Adaptive Strategies of the invasive aquatic plant, Ludwigia grandiflora subps. hexapetala: Contrasting Plasticity Between Aquatic and Terrestrial Morphotypes.

Biological invasion is the fifth biggest threat to biodiversity and ecosystem processes. Invasive species are able to colonise new environments rapidly due to their phenotypic plasticity. Ludwigia grandiflora subsp. hexapetala (Lgh), an aquatic invasive plant, invades various aquatic habitats, such as rivers, ponds, and more recently, especially in France, wet meadows. More recently, a terrestrial morphotype, emergent for half the year, has been identified. The behaviour of aquatic and terrestrial morphotypes in aquatic and terrestrial conditions was analysed through observations of morphological traits, and assays of metabolomics and phytohormones 14 and 28 days after the beginning of the experiment. The phenotypic plasticity was evaluated by calculating the relative distance plasticity index (RDPI) in response to environmental changes (terrestrial versus aquatic). RDPI were measured for morphological traits, metabolic and phytohormonal contents. Our results revealed that the terrestrial morphotype showed higher morphological trait values than the aquatic morphotype, independently of conditions, suggesting a pre-adaptation of Lgh to terrestrial habitats. The aquatic and terrestrial conditions shaped the Lgh metabolomic responses. However, the aquatic morphotype displayed higher phenotypic plasticity indexes than the terrestrial one. In addition, plasticity indexes evolved during the acclimatisation process, leading to increased RPDI values in most cases. The two morphotypes present distinct responses to aquatic and terrestrial conditions (especially in aquatic conditions for the terrestrial morphotype), highlighting the capacity of Lgh for invading new habitats due to its phenotypic plasticity, and a potential local adaptation. This study contributed to the understanding of how invasive species mobilise their phenotypic plasticity in new habitats, and the time required for local adaptation to occur.

plant biology↗

bioRxiv2024

Reproductive modes of polyploid Ludwigia grandiflora subsp. hexapetala in western Europe: the effects of a late-acting self-incompatibility system and its absence on genetic diversity within populations

Reproductive mode, i.e., the proportion of individuals produced by clonality, selfing and outcrossing in populations, determines how hereditary material is transmitted through generations. It shapes genetic diversity and its structure over time and space, which can be used to infer reproductive modes. Ludwigia grandiflora subsp. hexapetala (Lgh) is a partially clonal, polyploid, hermaphroditic, and heteromorphic plant that recently colonized multiple countries worldwide. In western Europe, individuals are either self-incompatible caused by a late-acting self-incompatibility (LSI) system developing long-styled flowers, or self-compatible (SC), with short-styled flowers. In this study, we genotyped 53 long- and short-styled populations newly colonizing France and northern Spain using SNPs to estimate rates of clonality, selfing and outcrossing. We found that populations reproduced mainly clonally but with a high diversity of genotypes along with rates of sexuality ranging from 10% up to 40%. We also found evidence for local admixture between long- and short-styled populations in a background of genetic structure between floral morphs that was twice the level found within morphs. Long- and short-styled populations showed similar rates of clonality but short-styled populations presented significantly higher rates of selfing, as expected considering their breeding system, and despite the small rates of failure of the LSI system. Within the 53 studied populations, the 13 short-styled populations had fewer effective alleles, lower observed heterozygosity, and higher inbreeding coefficients, linkage disequilibrium and estimates of selfing than what was found in long-styled populations. These results emphasize the necessity to consider the variation of reproductive modes when managing invasive plant species. The overall maintenance of higher genetic diversity with the possibility of maintaining populations clonally in the absence of compatible partners may explain why long-styled individuals seem to be more prevalent in all newly expanding populations worldwide. Beyond Lgh, our methodological approach may inspire future studies to assess the reproductive modes in other autopolyploid populations.

evolutionary biology↗