Developmental Dynamics of Bacterial Microbiota in Aphis gossypii Revealed Using Full-Length 16S rRNA Sequencing

The cotton aphid, Aphis gossypii, is a globally significant agricultural pest whose microbiota plays vital roles in its physiology and adaptation. However, the dynamics of bacterial communities across its developmental stages remain poorly understood. This study employed full-length 16S rRNA gene sequencing to characterize the microbiota structure, diversity, and functional potential in nine developmental stages of A. gossypii, including egg, nymph (1-, 3-, 5-, 7-day-old), and adult (1-, 3-, 5-, 7-day-old). Results revealed Proteobacteria (72.75–95.51%) as the dominant phylum across all stages, with Buchnera aphidicola (primary obligate symbiont) constituting over 23.83% of bacterial abundance and peaking in eggs (≈80%). Alpha diversity indices (Shannon, Simpson) indicated significantly higher microbial diversity in nymphs compared to adults, suggesting stage-specific ecological interactions. While beta diversity analysis showed no structural clustering by developmental stage, functional predictions highlighted enrichment in metabolic pathways (>73% of genes), though limitations in 16S-based functional inference were noted. Notably, facultative symbionts like Hamiltonella or Serratia were absent, contrasting with other aphid systems. Dynamic shifts in Buchnera titer and the prominence of Delftia tsuruhatensis and Enterobacter hormaechei implied potential roles in host adaptation. These findings highlight the persistent dominance of the obligate symbiont Buchnera aphidicola across all developmental stages, despite quantitative fluctuations in its abundance, alongside stage-specific shifts in facultative bacterial communities, offering insights into novel targets for microbiome-driven pest management strategies. Further multi-omics approaches are warranted to validate functional contributions of these microbial communities.