Maia, M. | Search bioRxiv

bioRxiv2025

The complete mitochondrial genome of Tunga penetrans and insights into flea phylogeny

Tungiasis, one of the oldest and most neglected tropical diseases endemic to sub-Saharan Africa and the Americas, is caused by the female parasitic flea, Tunga penetrans. The flea burrows into the skin, leading to acute and chronic inflammation, often exacerbated by bacterial superinfection. Despite its significant public health impact, genomic studies on T. penetrans are scarce. Here, we present the first complete mitochondrial genome of T. penetrans, comprising 17,279 base pairs and encoding 13 protein-coding genes, 22 transfer RNAs and 2 ribosomal RNAs. Phylogenetic analysis of the cox2 gene revealed a divergent basal lineage from Brazil, supporting a South American origin of T. penetrans and highlights genetic differentiation within the Americas. Clustering of the Ecuadorian and African isolates further suggests historical connections, likely linked to transatlantic maritime trade. The tree highlights a strong South American origin and evidence of migration and diversification, facilitated by human and animal movement. Phylogenetic analysis of the complete genomes relying on the protein-coding genes of other fleas revealed that T. penetrans is closely related to Dorcadia ioffi, a semi-sessile flea of goats and sheep in China. This mitochondrial genome provides a critical resource for future studies on molecular epidemiology, evolutionary history, and control of tungiasis.

genomics↗

bioRxiv2022

Grapevine leaf MALDI-MS imaging reveals the localisation of a putatively identified sucrose metabolite associated to Plasmopara viticola development

Despite well-established pathways and metabolites involved in grapevine-Plasmopara viticola interaction, information on the molecules involved in the first moments of pathogen contact with the leaf surface and their specific location is still missing. To understand and localise these molecules, we analysed grapevine leaf discs infected with P. viticola with MSI. Plant material preparation was optimised, and different matrices and solvents were tested. Our data shows that trichomes hamper matrix deposition and the ion signal. Results show that putatively identified sucrose presents a higher accumulation and a non-homogeneous distribution in the infected leaf discs in comparison with the controls. This accumulation was mainly on the veins, leading to the hypothesis that sucrose metabolism is being manipulated by the development structures of P. viticola. Up to our knowledge this is the first time that the localisation of a putatively identified sucrose metabolite was shown to be associated to P. viticola infection sites.

plant biology↗