Dependence on multiple nutritional bacterial symbionts forming a metabolic unit has repeatedly evolved in many insect species that feed on nutritionally unbalanced diets such as plant sap. This is the case for aphids of the subfamilies Lachninae and Chaitophorinae, which have evolved di-symbiotic systems in which the ancient obligate nutritional symbiont Buchnera aphidicola is metabolically complemented by an additional nutritional symbiont acquired more recently. Deciphering how different symbionts integrate both metabolically and anatomically in such systems is crucial to understanding how complex nutritional symbiotic systems function and evolve. In this study, we sequenced and analyzed the genomes of the symbionts B. aphidicola and Serratia symbiotica associated with the Chaitophorinae aphids Sipha maydis and Periphyllus lyropictus. Our results show that, in these two species, B. aphidicola and S. symbiotica complement each other metabolically (and their hosts) for the biosynthesis of essential amino acids and vitamins, but with distinct metabolic reactions supported by each symbiont depending on the host species. Furthermore, the S. symbiotica symbiont associated with S. maydis appears to be strictly compartmentalized into the specialized host cells housing symbionts in aphids, the bacteriocytes, whereas the S. symbiotica symbiont associated with P. lyropictus exhibits a highly invasive phenotype, presumably because it is capable of expressing a larger set of virulence factors, including a complete flagellum for bacterial motility. Such contrasting levels of metabolic and anatomical integration for two S. symbiotica symbionts that were recently acquired as nutritional co-obligate partners reflect distinct coevolutionary processes specific to each association.

Sesame (Sesamum indicum L.) is an ancient oilseed, aromatic, and medicinal crop widely used for its high-quality oil and seeds. The available genetic diversity in Morocco is too limited; thus, a mutagenesis breeding program was adopted. This study was carried out to evaluate the novel variability induced and observed in 11 M₄ mutant lines and to estimate some valuable genetic parameters. The experiment was conducted in two different environments using a randomized complete block design with three replications. Phenological, morphological, and agronomic traits were recorded. To estimate the effect of genotype, environment, and their interaction, ANOVA and planned contrast analyses were performed. To examine relatedness among genotypes, cluster analysis was performed. Significant differences among mutants and between parent cultivars and their respective mutant lines were observed. Genetic parameters such as genotypic (GCV) and phenotypic (PCV) coefficients of variation, broad-sense heritability (H² b.s), genetic advance (GA), and genetic advance over the mean (GAM) were high in most traits. Highly productive mutants, ‘US2-1’ and ‘US1-2’, were observed, exhibiting the highest number of capsules per plant and seed yield ever reported. Additionally, there are other promising mutants with early flowering, early maturity, and a reduced height of the first capsule. This suggests that mutagenesis can be successfully applied to develop high-yielding sesame varieties along with other improved phenological and agromorphological traits. All these mutant lines can be used as promising germplasm to develop competitive sesame cultivars to meet the increasing demand for sesame oil and seeds in the actual context of climate change.

Many insect species are associated with bacterial partners that can significantly influence their evolutionary ecology. Compared to other insect groups, aphids harbor a bacterial microbiota that has the reputation of being poorly diversified, generally limited to the presence of the obligate nutritional symbiontBuchnera aphidicolaand some facultative symbionts. In this study, we analyzed the bacterial diversity associated with the dogwood-grass aphidAnoecia corni, an aphid species that spends much of its life cycle in a subterranean environment. Little is known about the bacterial diversity associated with aphids displaying such a lifestyle, and one hypothesis is that close contact with the vast microbial community of the rhizosphere could promote the acquisition of a richer bacterial diversity compared to other aphid species. Using 16S rRNA amplicon Illumina sequencing on specimens collected on wheat roots in Morocco, we identified 10 bacterial operational taxonomic units (OTUs) corresponding to five bacterial genera. In addition to the obligate symbiontBuchnera, we identified the facultative symbiontsSerratia symbioticaandWolbachiain certain aphid colonies. The detection ofWolbachiais unexpected as it is considered rare in aphids. Moreover, its biological significance remains unknown in these insects. Besides, we also detectedArsenophonusandDactylopiibacterium carminicum. These results suggest that, despite its subterranean lifestyle,A.cornishelter a bacterial diversity mainly limited to bacterial endosymbionts.

The main objective of this research is to determine the composition and diversity of weed communities in the inter-rows of pomegranate orchards and to assess their impact on the abundance and diversity of arthropods. Weed diversity was assessed using the quadrat method, while arthropod sampling employed sweep netting, beating and collection shoot methods. Samples were collected weekly during the pomegranate cycle development. The results revealed the identification of a total of 17 weed species from 11 families. In 2022, we found that the three most abundant families were Amaranthaceae, Fumariaceae and Poaceae, which accounted for more than 90 % of the total sampled weeds, with proportions of 74.30 %, 8.09 % and 7.36 %, respectively. In 2023, the most dominant families were Solanaceae (30.03 %), Amaranthaceae (25.11 %) and Poaceae (16.18 %). Arthropods were associated with 12 weed species in 2022 but only 4 species in 2023, with Sonchus asper, Chenopodium album and Convolvulus arvensis hosting the highest arthropod abundance. While sweep netting sampling revealed no significant difference in arthropod abundance between years (p > 0.05). In addition, the shoot collection and beating methods revealed a significant positive effect of the weedy treatment on the abundance of beneficial arthropods (p < 0.05), with a significant difference observed between the two study years (p < 0.05). However, climatic variations also influenced the results across the seasons, with weeds supporting greater arthropod diversity and abundance, compared to bare ground. These findings highlight the role of weeds as a sustainable orchard management practice, promoting arthropod biodiversity and ecosystem services in pomegranate orchards, which may contribute to improving the productivity and management of pomegranate cultivation.