Catalogue Search | MBRL
Are you sure you want to remove the book from the shelf?
{{itemTitle}}
9
result(s) for
"Rouxel, Sebastien"
Sort by:
A gene-for-gene interaction involving a ‘late’ effector contributes to quantitative resistance to the stem canker disease in Brassica napus
• The control of stem canker disease of Brassica napus (rapeseed), caused by the fungus Leptosphaeria maculans is based largely on plant genetic resistance: single-gene specific resistance (Rlm genes) or quantitative, polygenic, adult-stage resistance. Our working hypothesis was that quantitative resistance partly obeys the gene-for-gene model, with resistance genes ‘recognizing’ fungal effectors expressed during late systemic colonization.
• Five LmSTEE (stem-expressed effector) genes were selected and placed under the control of the AvrLm4-7 promoter, an effector gene highly expressed at the cotyledon stage of infection, for miniaturized cotyledon inoculation test screening of a gene pool of 204 rapeseed genotypes.
• We identified a rapeseed genotype, ‘Yudal’, expressing hypersensitive response to LmSTEE98. The LmSTEE98–RlmSTEE98 interaction was further validated by inactivation of the LmSTEE98 gene with a CRISPR-Cas9 approach. Isolates with mutated versions of LmSTEE98 induced more severe stem symptoms than the wild-type isolate in ‘Yudal’. This single-gene resistance was mapped in a 0.6 cM interval of the ‘Darmor_bzh’ × ‘Yudal’ genetic map.
• One typical gene-for-gene interaction contributes partly to quantitative resistance when L. maculans colonizes the stems of rapeseed. With numerous other effectors specific to stem colonization, our study provides a new route for resistance gene discovery, elucidation of quantitative resistance mechanisms and selection for durable resistance.
Journal Article
Using deep-neural-network-driven facial recognition to identify distinct Kabuki syndrome 1 and 2 gestalt
Kabuki syndrome (KS) is a rare genetic disorder caused by mutations in two major genes, KMT2D and KDM6A, that are responsible for Kabuki syndrome 1 (KS1, OMIM147920) and Kabuki syndrome 2 (KS2, OMIM300867), respectively. We lack a description of clinical signs to distinguish KS1 and KS2. We used facial morphology analysis to detect any facial morphological differences between the two KS types. We used a facial-recognition algorithm to explore any facial morphologic differences between the two types of KS. We compared several image series of KS1 and KS2 individuals, then compared images of those of Caucasian origin only (12 individuals for each gene) because this was the main ethnicity in this series. We also collected 32 images from the literature to amass a large series. We externally validated results obtained by the algorithm with evaluations by trained clinical geneticists using the same set of pictures. Use of the algorithm revealed a statistically significant difference between each group for our series of images, demonstrating a different facial morphotype between KS1 and KS2 individuals (mean area under the receiver operating characteristic curve = 0.85 [p = 0.027] between KS1 and KS2). The algorithm was better at discriminating between the two types of KS with images from our series than those from the literature (p = 0.0007). Clinical geneticists trained to distinguished KS1 and KS2 significantly recognised a unique facial morphotype, which validated algorithm findings (p = 1.6e−11). Our deep-neural-network-driven facial-recognition algorithm can reveal specific composite gestalt images for KS1 and KS2 individuals.
Journal Article
Effects of blue light on the biochemical composition and photosynthetic activity of Isochrysis sp. (T-iso)
In aquaculture, particularly in bivalve hatcheries, the biochemical composition of algal diets has a strong influence on larval and post-larval development. Biochemical composition is known to be related to culture conditions, among which light represents a major source of variation. The effects of blue light on biochemical composition and photosynthetic rate of Isochrysis sp. (T-iso) CCAP 927/14 were assessed in chemostat at a single irradiance (300 μmol photons m⁻² s⁻¹) and compared with white light. Two different dilution (renewal) rates were also tested: 0.7 and 0.2 d⁻¹. Relative carbohydrate content was lower under blue light than under white light at both dilution rates, whereas chlorophyll a and photosynthesis activity were higher. In contrast, carbon quota was lower and protein content higher under blue light than under white light, but only at 0.7 d⁻¹. Despite these metabolic differences, cell productivity was not significantly affected by the spectrum. However, the nitrogen to carbon ratio and photosynthetic activity were higher at 0.7 d⁻¹ than at 0.2 d⁻¹, while carbon quota and carbohydrate content were lower. Our results show that blue light may influence microalgal metabolism without reducing productivity for a given growth rate, a result that should be of great interest for microalgal production in aquaculture.
Journal Article
“Late” effectors from Leptosphaeria maculans as tools for identifying novel sources of resistance in Brassica napus
The Dothideomycete Leptosphaeria maculans, causing stem canker (blackleg) of Brassica napus, secretes different cocktails of effectors at specific infection stages. Some effectors (\"Late\" effectors) are specifically produced during the long asymptomatic phase of stem colonization. By manipulating their expression so that they are overexpressed during cotyledon infection (OEC transformants of the fungus), we previously postulated that resistance genes operating in the stem may be involved in gene-for-gene relationship and thus contribute to quantitative disease resistance (QDR). Here, we selected 10 relevant new effector genes, and we generated OEC transformants to screen a collection of 130 B. napus genotypes, representative of the available diversity in the species. Five B. napus accessions showed a typical hypersensitive response when challenged with effectors LmSTEE98 or LmSTEE6826 at the cotyledon stage, and all belong to the semi-winter type of the diversity panel. In addition, five winter-type genotypes displayed an intermediate response to another late effector, LmSTEE7919. These new interactions now have to be genetically validated to check that they also correspond to gene-for-gene interactions. In all cases, they potentially provide novel resources, easy to breed for, and accounting for part of the quantitative resistance in a species for which we are currently facing limited resistance sources.
Journal Article
IMPACT OF ARCHITECTURAL REPRESENTATION ON USERS' FEELINGS: FROM 2D PLANS TO VIRTUAL MODELS AND PHYSICAL PROTOTYPES
User integration in the architectural design process raises the issue of tools for communicating between architectural-design experts and human-factor experts or users. Architectural representations, such as two-dimensional (2D) plans, cardboard models, and three-dimensional (3D) renderings, should be used to support the active participation of users. However, previous studies have highlighted the limitations of the most conventionally used architectural representations, and the feelings induced by the environment are difficult to anticipate during the architectural design process. This study focused on the impact of six architectural representations — 2D plans, cardboard models, 3D renderings, CAD models, full-scale virtual models, and full-scale physical prototypes — on users' feelings in the context of office design. The study found that, while users' feelings with regard to use, aesthetics, and emotion in relation to office design were similar for the full-scale virtual model and full-scale physical prototype, they were different for the other representation types. Therefore, these representation types should only be used with experts such as architects. To support the active participation of users, full-scale virtual models and full-scale physical prototypes should be proposed. Indeed, these representation types can aid in the study of the feelings an environment induces in users.
Journal Article
Effects of blue light on the biochemical composition and photosynthetic activity of Isochrysis sp. (T-iso)
In aquaculture, particularly in bivalve hatcheries, the biochemical composition of algal diets has a strong influence on larval and post-larval development. Biochemical composition is known to be related to culture conditions, among which light represents a major source of variation. The effects of blue light on biochemical composition and photosynthetic rate of Isochrysis sp. (T-iso) CCAP 927/14 were assessed in chemostat at a single irradiance (300 μmol photons m−2 s−1) and compared with white light. Two different dilution (renewal) rates were also tested: 0.7 and 0.2 d−1. Relative carbohydrate content was lower under blue light than under white light at both dilution rates, whereas chlorophyll a and photosynthesis activity were higher. In contrast, carbon quota was lower and protein content higher under blue light than under white light, but only at 0.7 d−1. Despite these metabolic differences, cell productivity was not significantly affected by the spectrum. However, the nitrogen to carbon ratio and photosynthetic activity were higher at 0.7 d−1 than at 0.2 d−1, while carbon quota and carbohydrate content were lower. Our results show that blue light may influence microalgal metabolism without reducing productivity for a given growth rate, a result that should be of great interest for microalgal production in aquaculture.
Journal Article
Effects of host sex, age and behaviour on co-infection patterns in a wild ungulate
Recent zoonotic disease emergences reveal the importance of studying wildlife parasite communities. As wild hosts frequently harbour diverse parasite species, understanding the drivers of multiple infection patterns in free-ranging hosts is critical for elucidating the ecological and epidemiological dynamics of parasite communities. In this study, we analysed co-infection patterns in European roe deer (Capreolus capreolus) inhabiting a fragmented rural landscape in southwestern France. Using data from 130 GPS-tracked roe deer, we examined the influence of proximity to livestock, host activity levels, age, sex, and between-parasite interactions on the presence of 11 parasitic taxa. Hierarchical modelling of species communities (HMSC) revealed that proximity to livestock significantly increased the likelihood of infection with orofecally transmitted parasites (Toxoplasma gondii, gastrointestinal parasites). Sex and age were other key predictors, with males and juveniles exhibiting a higher frequency of parasite presence, likely influenced by hormonal and immune system differences. Activity levels showed distinct age-related effects, with higher activity levels being positively associated with increased parasite prevalence in yearlings, but not in adults. In contrast, parasite association patterns within individual hosts were weak, suggesting minimal interactions between parasite species. Our findings highlight the interplay between exposure and susceptibility in shaping co-infection patterns and underscore the value of hierarchical modelling approaches in multi-parasite systems.Competing Interest StatementThe authors have declared no competing interest.
Paper