Biology subjects

Fortier, A.-M.

Publications and source records attributed to Fortier, A.-M..

6 recordsLinked to original sources

bioRxiv2026

Who, what, when, where: Phenological trends of the Seedcorn Maggot Complex (Diptera: Anthomyiidae) in three vegetable crops in Southern Quebec

In eastern Canada, the seedcorn maggot complex (SMC) includes three agriculturally important taxa: Delia platura biotypes H and N, and D. florilega. Because their larvae are morphologically indistinguishable, field-collected individuals are often grouped together despite differences in phenology and life history. Using larval collections from broccoli, green onion, and dry onion fields in Southern Quebec (2017-2022), we identified specimens via HRM analysis and characterized taxon-specific phenology and abundance using Bayesian hierarchical generalized additive models. In Allium crops, D. platura biotype N dominated early-season infestations (May), followed by a shift in early June towards increased abundance of biotype H and D. florilega. In broccoli, all SMC members appeared later, with overlapping abundance peaks in June. These results reveal strong crop-dependent phenological differences and underscore the need to treat SMC members as distinct biological entities in pest management. The implications for optimizing an emerging sterile insect technique (SIT) program for D. platura in Quebec are significant: field releases of sterile males should target early-season biotype N in Allium crops, followed by releases of both biotypes later in the season in broccoli to maximize control efficacy.

ecology↗

bioRxiv2025

Multi-omics analysis of TNBC organoids identifies phosphorylation of the membrane trafficking machinery as a key event associated with FER-mediated invasion

Triple Negative Breast Cancer (TNBC) is characterised by unfavourable outcome due to the combination of its metastatic propensity, chemo-refractory behaviour and the lack of effective targeted interventions. Expression of the feline sarcoma-related (FER) kinase constitutes an independent prognostic factor that correlates with poor patient survival. FER promotes invasive behaviour in TNBC cells by regulating endosomal sorting and recycling (ESR) of adhesion proteins. Yet, the ESR machinery supporting invasion in TNBC, particularly within 3D environments, remains poorly understood. Here, we used FER-expressing TNBC patient-derived xenograft organoids (PDXOs) and MDA-MB-231 cells to identify the membrane trafficking machinery promoting invasion. Using a combination of proteomics, phospho-proteomics, and single cell RNA-sequencing, we show that the invasion of FER-expressing PDXO cells in collagen-I is mainly associated with the differential phosphorylation of membrane trafficking regulators, including SEC16A and a marked increase in Rab4-positive tubules. SEC16A depletion impairs cell invasion and reduces the number of focal adhesions and Rab4-positive tubules. Importantly, FER regulates SEC16A levels and localization, specifically in TNBC. Altogether, we identified SEC16A as a key player in FER-driven TNBC invasion, highlighting the membrane trafficking machinery as a promising target for the development of new therapeutic strategies.

cancer biology↗

bioRxiv2025

Multimodal profiling unveils a reversible basal-like breast cancer cell state resistant to AKT inhibition

The PI3K/AKT/mTOR pathway is central to cell metabolism and growth. However, pharmacological inhibition of the pathway is not uniformly effective across cancer types, or even within a single cancer model. In this study, we leverage oblique plane microscopy of triple negative breast cancer organoids, as well as lineage tracing to uncover a source of heterogeneity. Non-genetic resistance to AKT inhibition is associated with basal cell features of normal breast epithelium and the master transcription factor of basal cell state, {Delta}Np63, is sufficient to confer resistance. Cells can transition between states within four weeks and therefore, AKT inhibition only delays tumour growth, with tumours rich in KRT14+ cells resulting. Thus, under selection, triple negative breast cancer exploits a repertoire of cell states inherent to the breast.

cancer biology↗

bioRxiv2025

Sterile insect technique reduces cabbage maggot (Diptera: Anthomyiidae) infestation in root crucifers in Canada

The cabbage maggot (Delia radicum Linnaeus) is a major pest of brassica vegetables in Canada that has traditionally been managed with soil-applied insecticides. However, recent regulatory restrictions on key products such as chlorpyrifos have created a pressing need for alternative solutions. This study evaluates the sterile insect technique (SIT) as a control method for the cabbage maggot in root crucifers. Large-scale field trials conducted from 2019 to 2022 in Quebec (Canada) demonstrated significant reductions in D. radicum infestations in radish and daikon crops. Quality control measures confirmed the effectiveness of sterilization, with minimal impact on male performance. The results suggest that the SIT is a promising, environmentally friendly alternative to chemical control for cabbage maggot management. The study further highlights the importance of optimizing release strategies and improving predictive models to guide deployment. Overall, the SIT offers growers a viable option to reduce reliance on insecticides while maintaining crop health and yield.

ecology↗

bioRxiv2023

REPRODUCTIVE COMPATIBILITY OF TWO LINES OF DELIA PLATURA (DIPTERA: ANTHOMYIIDAE)

Accurate identification of agricultural pests is a major component of integrated pest management. The seedcorn maggot, Delia platura (Diptera: Anthomyiidae), is a cosmopolitan polyphagous pest species which may be found in high numbers in numerous crops. Two morphologically identical genetic lines of D. platura (H- and N- lines) with distinct distributions were recently identified. However, no study to date has investigated the reproductive compatibility of the two lines and thus the possibility that they may actually be two unique biological entities. A previous study described the reproductive traits of the two lines and suggested that H-line females are highly selective towards the male with which they mate, pointing to a possible pre-mating isolation mechanism between the lines. Using laboratory-reared colonies originating from the Monteregie region in Quebec, this study investigates the reproductive compatibility of the two D. platura lines. We found that only one of thirty H-line females was inseminated by an N-line male, further suggesting mate choice as a pre-mating isolation mechanism between the lines. However, N-line females were readily inseminated by H-line males, suggesting a lack of pre-mating isolation in this type of cross. The eggs laid by N-line females mated with H-line males had a lower hatching rate than the ones laid by females of intra-line crosses suggesting either post-mating pre-zygotic or post-zygotic partial isolation. However, the larvae that did hatch had a comparable developmental success to those from intra-line crosses in terms of survival and developmental time from larval hatching to adult emergence, pupal weight, and adult sex ratio, suggesting a lack of post-zygotic isolation for these life stages. Considering the different biological traits of the two lines, we suggest the use of the biotype terminology to designate the two biological entities and discuss their implications for integrated pest management.

ecology↗

bioRxiv2023

Evolution of chromosome arm aberrations in breast cancer through genetic network rewiring

The basal breast cancer subtype is enriched for triple-negative breast cancer (TNBC) and displays consistent large chromosomal deletions. Here, we characterize the evolution and maintenance of chromosome 4p (chr4p) loss in basal breast cancer. TCGA data analysis showed recurrent deletion of chr4p in basal breast cancer. Phylogenetic analysis of a unique panel of 23 primary tumor/patient-derived xenograft basal breast cancers revealed early evolution of chr4p deletion. Mechanistically we show that Chr4p loss is associated with enhanced proliferation. Gene function studies identified an unknown gene, C4orf19, within chr4p, which suppressed proliferation when overexpressed and is a novel member of a PDCD10-GCKIII kinase module, we name as PGCA1. Genome-wide pooled overexpression screens using a barcoded library of human open reading frames, identified chromosomal regions, including chr4p, that suppress proliferation when overexpressed in a context-dependent manner implicating network interactions. Together this sheds light on the early emergence of complex aneuploid karyotypes involving chr4p and adaptive landscapes shaping breast cancer genomes.

genomics↗