Biology subjects

Gonzalez, A.-A.

Publications and source records attributed to Gonzalez, A.-A..

3 recordsLinked to original sources

bioRxiv2024

Identification of genetic bases of male fertility in Pyricularia oryzae by Genome Wide Association Study (GWAS).

The reproductive system of an organism impacts the emergence and evolution of adaptive variants in response to selective constraints. The understanding of the sexual mode of reproduction in pathogens helps to understand their life history. In filamentous Ascomycete fungi, mating type system and the production of gametes are required to reproduce sexually. In the phytopathogenic Ascomycete Pyricularia oryzae, studies of the genetic determinants of sexual reproduction are still limited to the mating type system. This study focuses on identifying the genes involved in male fertility through the production of male gametes known as microconidia. We performed a GWAS analysis coupled with a local score approach on a wild recombinant population of Pyricularia oryzae phenotyped for microconidia production. We identified one genomic region significantly associated with the quantity of microconidia produced. This region contained nine candidate genes, some of them annotated with functions associated to sexual reproduction in model fungi such as Neurospora crassa, Podospora anserina and Sordaria macrospora. The most promising candidate gene contains a Jumonji domain. Proteins belonging to the Jumonji family are conserved among Eukaryotes and are known to be involved in chromatin regulation.

genetics↗

bioRxiv2023

Dynamics of macrophage polarization support Salmonella persistence in a whole living organism

Numerous intracellular bacterial pathogens interfere with macrophage function, including macrophage polarization, to establish a niche and persist. However, the spatiotemporal dynamics of macrophage polarization during infection within host remain to be investigated. Here, we implement a model of persistent Salmonella Typhimurium infection in zebrafish, which allows visualization of polarized macrophages and bacteria in real time at high-resolution. While macrophages polarize toward M1-like phenotype to control early infection, during later stages, Salmonella persists inside non-inflammatory clustered macrophages. Transcriptomic profiling of macrophages confirmed a highly dynamic signature during infection characterized by a switch from pro-inflammatory to anti-inflammatory/pro-regenerative status and revealed a shift in adhesion program. In agreement with this specific adhesion signature, macrophage trajectory tracking identifies motionless macrophages as a permissive niche for persistent Salmonella. Our results demonstrate that zebrafish model provides a unique platform to explore, in a whole organism, the versatile nature of macrophage functional programs during bacterial acute and persistent infections.

immunology↗

bioRxiv2018

Using insects to detect, monitor and predict the distribution of Xylella fastidiosa: a case study in Corsica

We sampled ca 2500 specimens of Philaenus spumarius throughout Corsica without a priori on the presence of symptoms on plants. We screened 448 specimens for the presence of Xylella fastidiosa (Xf) using qPCR and a custom nested PCR. qPCR appeared versatile and under-estimated the prevalence of Xf. Nested PCR showed that Xf was present in all populations. Molecular results were validated by prediction on the distribution of Xf made from tests conducted on plants, which shows the pertinence of using vectors in risk assessment studies. Xf was detected in tenerals and adults. Thus, P. spumarius could acquire Xf from its host plant, mostly Cistus monspeliensis in Corsica, which may act as reservoir for the next season. This contrasts with other observations and suggests that management strategies may have to be adapted on a case-by-case basis. At least two genetic entities and several variants of Xf not yet identified on plants were present in the insects, which suggests ancient introductions of Xf and a probable underestimation of the current diversity of the strains present in Corsica. Interestingly 6% of the specimens carried two subspecies. Studies are wanted to better characterize the strains present in Corsica and know how the disease was introduced, spread and why no sign of a potential epidemic was detected earlier. This study shows that, when sensitive enough methods are implemented, insects can be used to predict and better assess the exact distribution of Xf. Insects are indeed easy to collect, Xf multiply only in their foregut and does not become circulative, which facilitates its detection.\n\nKey messageO_LIInsect vectors can be used to detect, monitor and predict the distribution of Xylella fastidiosa\nC_LIO_LIThe widely used qPCR approach is not sensitive enough to detect low bacterial load\nC_LIO_LIDifferent strains/subspecies of Xf are widely distributed in Corsica which suggests old introduction(s)\nC_LIO_LIStrategies to manage Xf may need to be set up on a case-by-case basis\nC_LIO_LIThere is an urgent need to take stock of the situation in Europe to avoid unnecessary economic pressure on certain geographical areas and agricultural sectors.\nC_LI

ecology↗