Ecological origin and natural Trypanosoma cruzi infection are associated with reconfiguration of the Rhodnius pallescens midgut microbiome

Abstract

The intrusion of the secondary vector Rhodnius pallescens into urban and peri-urban environments in Colombia poses an emerging risk for Chagas disease transmission, compounded by rising insecticide resistance. Developing novel control strategies requires the identification of stable gut symbionts; however, high-resolution microbial profiles for urban-intruding vector populations remain poorly defined. To characterize the intestinal microbiome and identify candidate taxa for paratransgenesis, we generated high-resolution taxonomic composition and predicted functional profiles using 16S rRNA amplicon sequencing of individually processed midgut tissues from laboratory-reared and wild-caught adult R. pallescens with and without Trypanosoma cruzi infection collected in the Bucaramanga metropolitan area, Andean region, Santander, Colombia. Beta diversity analyses revealed that ecological origin and infection status significantly drive microbial restructuring (PERMANOVA P = 0.001). The transition from a sylvatic to a laboratory environment induced a severe taxonomic contraction dominated by the genus Dickeya (79.19% relative abundance). From these wild-type insects, non-infected populations maintained a balanced, functionally redundant midgut community featuring Dickeya (46.82%), Williamsia (20.6%), and Corynebacterium (16.76%). On the other hand, natural T. cruzi colonization was associated with a marked taxonomic reorganization in wild vectors, characterized by the marked expansion of Actinobacteriota, specifically Williamsia (51.22%) and Nocardia (29.99%), alongside an enrichment of predicted pathways for oxidative stress management. Therefore, we hypothesize that ecological origin and T. cruzi infection are primary determinants of microbial structure in R. pallescens. In naturally infected insects, we identify the genus Williamsia as a priority candidate for future studies aimed at evaluating its stability, cultivability, functional role, and potential use in paratransgenic strategies.