Biology subjects

Bruno, P.

Publications and source records attributed to Bruno, P..

3 recordsLinked to original sources

bioRxiv2026

Leishmaniamajor co-opts IL-7 feedback in monocytes to suppress CD4⁺ T-cell immunity

During immune responses, pro-and anti-inflammatory mechanisms must be balanced to ensure pathogen clearance while limiting tissue damage. Monocyte-derived cells contribute to both processes, yet the underlying regulatory circuits remain incompletely defined. Here, we show that a subset of PDPN+IL-7R+ monocyte-derived cells that impair effector CD4 T cell-mediated control of intracellular pathogens, and thus perpetuate the infection. Fibroblast-derived IL-7 drives this immunosuppressive program, which is up-regulated in response to IFN{gamma}. We thus uncover a cytokine-dependent feedback circuit in which elevated IFN{gamma} induces IL-7 production by fibroblasts, licensing immunosuppressive monocyte-derived cells that restrain CD4 T cell responses. This mechanism links excessive inflammation to immune suppression at the expense of pathogen control. Targeting this feedback loop may enable therapeutic strategies that enhance antimicrobial immunity while preserving tissue integrity.

immunology↗

bioRxiv2025

Oviposition behavior, nymphal development, and below-ground olfactory preference of Pentastiridius leporinus on twelve Beta vulgaris genotypes

The planthopper Pentastiridius leporinus (Hemiptera: Cixiidae) is the primary vector of two phloem-restricted prokaryotes, which can cause the disease syndrome de basses richesses (SBR) in sugar beet (Beta vulgaris L.). Heavy infestations of this insect have contributed to significant yield losses in Central Europe, but little is known about how different B. vulgaris genotypes influence vector behavior and performance. Understanding such interactions is critical for both pest management and the development of sugar beet cultivars that are less favorable to the vector. We investigated oviposition decisions, nymphal development, and belowground chemotaxis of P. leporinus using twelve B. vulgaris genotypes: eight sugar beet genotypes with contrasting SBR tolerance, two Swiss chard, and two beetroot varieties. In no-choice assays, females oviposited at similar rates on all tested genotypes, indicating broad host suitability. However, in three-choice tests, significant differences emerged, with several genotypes receiving more egg batches than the reference variety Vasco. Despite adult host preferences, nymphal survival, growth, and instar development did not differ among genotypes. In contrast, belowground olfactometer assays revealed that nymphs exhibited clear chemotactic responses: several genotypes attracted significantly more individuals than others. This represents the first documentation of chemotactic host location in P. leporinus nymphs. Our findings reveal a mismatch between adult oviposition preference and nymphal performance, a pattern not uncommon in other generalist herbivores. Both adult and nymphal behaviors were nevertheless influenced by genotype-specific traits, likely linked to plant chemistry. Identifying these cues could inform breeding strategies aimed at reducing vector attraction, thereby complementing pathogen-targeted approaches and supporting integrated management of SBR in sugar beet.

ecology↗

bioRxiv2025

Soil phosphate availability modulates the arbuscular mycorrhizal fungal community and mycorrhizal nutrition in wheat

O_LIUnderstanding the contributions of arbuscular mycorrhizal fungi (AMF) to plant nutrition is essential for sustainable agriculture. We hypothesised that soil phosphorus (P) availability modulates the diversity and functionality of wheat root-associated AMF community, particularly the mycorrhizal nutrition. C_LIO_LIWheat plants were sampled over two campaigns (2019 and 2022) in a long-term P fertilisation trial. The expression of the wheat transporters involved in the mycorrhizal nutrition was assessed by RT-qPCR, and AMF community composition by metabarcoding. Complementary experiments under controlled conditions were performed to further study the interaction between nitrogen (N) and P availability on AM. C_LIO_LIDifferent effects of P on AMF colonisation and transporter expression were observed in field-grown wheat depending on the campaigns, which differed in wheat N status. Controlled experiments confirmed that AMF colonisation depends on the limitation of either P or N, but that regulation of peri-arbuscular phosphate, ammonium and nitrate transporters depends on the nature of the limiting soil nutrients. Additionally, AMF communities varied according to the soil P availability, with the Funneliformis genus becoming more dominant under high P conditions for both years. C_LIO_LITogether, our findings show that N and P availability jointly shape root AMF communities and AM functioning. Combining community profiling and molecular markers of colonisation and nutrition offers a framework to better understand AMF contributions to plant nutrition across agroecosystems. C_LI

plant biology↗