Biology subjects

Filee, J.

Publications and source records attributed to Filee, J..

3 recordsLinked to original sources

bioRxiv2022

Wolbachia genomics support a tripartite nutritional symbiosis in blood-sucking Triatomine bugs

The nutritional symbiosis promoted by bacteria is a key determinant for adaptation and evolution of many insect lineages. A complex form of nutritional mutualism that arose in blood-sucking insects critically depends on diverse bacterial symbionts that supplement the diet of their nutrient-poor hosts with B vitamins. For instance, the triatomine bug Rhodnius prolixus, one of the main vectors of the Chagas disease in humans, is known to maintain a nutritional symbiosis with the gut symbionts Rhodococcus rhodnii. In this study, we show that Wolbachia symbionts are also widely distributed in the Rhodnius genus. We have screened a large set of Rhodnius blood-sucking bugs samples belonging to 17 different species and to the three phylogenetic groups, prolixus, pallescens and pictipes. We assembled 13 genomes of Wolbachia infecting eight Rhodnius species from prolixus and pictipes groups. We demonstrate that these Wolbachia belong to supergroup F and are closely related to Wolbachia infecting the bedbug Cimex lectularius (wCle). Although bedbugs and triatomines are very distantly related hemipteran bugs, the genomes of their respective Wolbachia were highly similar, suggesting recent horizontal host switches. We also show that Rhodnius Wolbachia genomes infecting the prolixus group encode intact biotin operon, the hallmark of nutritional symbiosis in bedbugs. This operon is lacking from all the other Wolbachia infecting R. pictipes. Finally, host genome analyses provide evidence of massive Wolbachia-to-Rhodnius gene transfers in almost samples, providing footprints of past infections that support a widespread and probably ancient symbiotic association between Wolbachia and triatomine bugs. Our results suggest that both Wolbachia and R. rhodnii gut symbionts and their Rhodnius host maintain a highly prevalent symbiotic relationship, in which the vertically-inherited Wolbachia has the metabolic potantial to ensure or complement, the nutritional mutualism provided by the gut symbionts. Specific loss of the biotin operon in some symbiont genomes suggests that the boundaries between obligatory mutualism, facultative mutualism and parasitism in Wolbachia are transient and fluid, supporting a dynamic process of transition and reversion from one state to another.

evolutionary biology↗

bioRxiv2021

Bacterial origin of thymidylate and folate metabolism in Asgard Archaea

Little is known about the evolution and biosynthetic function of DNA precursor and the folate metabolism in the Asgard group of archaea. As Asgard occupy a key position in the archaeal and eukaryotic phylogenetic trees, we have exploited very recently emerged genome and metagenome sequence information to investigate these central metabolic pathways. Our genome-wide analyses revealed that the recently cultured Asgard archaeon Candidatus Prometheoarchaeum syntrophicum strain MK-D1 (Psyn) contains a complete folate-dependent network for the biosynthesis of DNA/RNA precursors, amino acids and syntrophic amino acid utilization. Altogether our experimental and computational data suggest that phylogenetic incongruences of functional folate-dependent enzymes from Asgard archaea reflect their persistent horizontal transmission from various bacterial groups, which has rewired the key metabolic reactions in an important and recently identified archaeal phylogenetic group. We also experimentally validated the functionality of the lateral gene transfer of Psyn thymidylate synthase ThyX. This enzyme uses bacterial-like folates efficiently and is inhibited by mycobacterial ThyX inhibitors. Our data raise the possibility that the thymidylate metabolism, required for de novo DNA synthesis, originated in bacteria and has been independently transferred to archaea and eukaryotes. In conclusion, our study has revealed that recent prevalent lateral gene transfer has markedly shaped the evolution of Asgard archaea by allowing them to adapt to specific ecological niches.

microbiology↗

bioRxiv2021

The natural history of the black soldier fly, Hermetia illucens: insights from complete mitochondrial genome sequences

The Black Soldier Fly (BSF) Hermetia illucens is a cosmopolitan fly heavily used by industrial companies to reduce biowaste and produce protein and fat for poultry and aquaculture feed. However, the natural history and the genetic diversity of the BSF is poorly known. In this study, we analysed 677 CO1 sequences derived from samples found all over the five continents leading us to the discovery of 52 haplotypes including 10 major haplotypes. We refined the definition of these haplotypes by sequencing 59 mitochondrial genomes. We could derive an estimate of the separation events of the different haplotypes at more than two million years for the oldest branches. This worldwide cryptic genetic and genomic diversity is mirrored at local scale in France in which we found five major haplotypes sometimes in sympatry. Our data resolve the phylogenetic relationships between the major lineages and give insights into the dispersal and the numbers of BSF neo-introduction at global and local scales. Our results indicate that the genetic and genomic diversity of commercial BSF stock is very low and these brood stock participated in the dissemination of the BSF in the wild. Taken together these results call for a better understanding of the genomic diversity of the BSF to unravel possible specific adaptations of the different lineages for industrial needs and to initiate the selection process.

evolutionary biology↗