Biology subjects

Loisier, A.

Publications and source records attributed to Loisier, A..

3 recordsLinked to original sources

bioRxiv2023

Temporal stability of sex ratio distorter prevalence in natural populations of the isopod Armadillidium vulgare

AbstractIn the terrestrial isopod Armadillidium vulgare, many females produce progenies with female-biased sex ratios due to two feminizing sex ratio distorters (SRD): Wolbachia endosymbionts and a nuclear non-mendelian locus called the f element. To investigate the potential impact of these SRD on the evolution of host sex determination, we analyzed their temporal distribution in six A. vulgare populations sampled up to six times over 12 years, for a total of 29 time points. SRD distribution was heterogeneous among populations despite their close geographic locations, so that when one SRD was frequent in a population, the other SRD was rare. In contrast with spatial heterogeneity, our results overall did not reveal substantial temporal variability in SRD prevalence within populations, suggesting equilibria in SRD evolutionary dynamics may have been reached or nearly so. Temporal stability was also generally reflected in mitochondrial and nuclear variation. Nevertheless, in a population, a Wolbachia strain replacement coincided with changes in mitochondrial composition but no change in nuclear composition, thus constituting a typical example of mitochondrial sweep caused by endosymbiont rise in frequency. Rare incongruence between Wolbachia strains and mitochondrial haplotypes suggested the occurrence of intraspecific horizontal transmission, making it a biologically relevant parameter for Wolbachia evolutionary dynamics in A. vulgare. Overall, our results provide an empirical basis for future studies on SRD evolutionary dynamics in the context of multiple sex determination factors co-existing within a single species, to ultimately evaluate the impact of SRD on the evolution of host sex determination mechanisms and sex chromosomes.

evolutionary biology↗

bioRxiv2023

Genome sequence and annotation of Periconia digitata, a promising biocontrol agent of phytopathogenic oomycetes

The Periconia fungal genus belongs to the phylum Ascomycota, order Pleosporales, family Periconiaceae. Periconia are found in many habitats but little is known about their ecology. Several species from this genus produce bioactive molecules. Periconia digitata extracts were shown to be deadly active against the pine wilt nematode. Furthermore, P. digitata was shown to inhibit plant pathogenic oomycete Phytophthora parasitica. Because P. digitata has great potential as a biocontrol agent and high quality genomic resources are still lacking in the Periconiaceae family, we generated long-read genomic data for P. digitata. Using the PacBio Hifi sequencing technology, we obtained a highly-contiguous genome assembled in 13 chromosomes and totalling ca. 39 Mb. In addition, we produced a reference transcriptome, based on 12 different culture conditions, and proteomic data to support the genome annotation. Besides representing a new reference genome within the Periconiaceae, this work will contribute to our better understanding of the Eukaryotic tree of life and opens new possibilities in terms of biotechnological applications.

microbiology↗

bioRxiv2020

Malacological survey in a bottle of water: A comparative study between manual sampling and environmental DNA metabarcoding approaches

AO_SCPLOWBSTRACTC_SCPLOWTo assess the effect of anthropogenic activities on ecosystems, it is of prime importance to develop new tools enabling a rapid characterisation of ecological communities. Freshwater ecosystems are particularly impacted and threatened by human activities and need thorough attention to preserve their biodiversity and the ecological services they provide. Studying such ecosystems is generally difficult because the associated organisms are hard to sample and to monitor. We present a ready to use environmental metabarcoding diagnostic tool to characterise and monitor the freshwater malacofauna from water samples. The efficiency of this new tool was compared to a classical malacological survey at 19 sampled sites from 10 distinct rivers distributed over Corsica Island (France). Our eDNA monitoring tool demonstrated a remarkable ability to reconstitute the local malacofauna compared to the malacological survey, with 97.1% of species detection confirmed by both methods. The present tool successfully detected the 11 freshwater snail species previously reported in Corsica by malacological survey but was limited at the genus level for some species. Moreover, our malacological survey allowed an update of the local distribution of a wide diversity of freshwater snails including invasive species (i.e. Potamopyrgus antipodarum and Physa acuta) as well as snail hosts of pathogens of medical and veterinary importance (i.e. Bulinus truncatus and Galba truncatula).

ecology↗