Multi-Omic Analysis of Symbiotic Bacteria Associated With Aedes aegypti Breeding Sites

Abstract

Mosquito breeding sites are complex aquatic environments with wide microbial diversity and physicochemical parameters that can change over time during the development of immature insect stages. Changes in biotic and abiotic conditions in water can alter life-history traits of adult mosquitos but this area remains understudied. Here, using microbial genomic and metabolomics analyses, we explored the metabolites associated with Aedes aegypti breeding sites as well as the potential contribution of Klebsiella sp., symbiotic bacteria highly associated with mosquitoes. We sought to address whether breeding sites have a signature metabolic profile and understand the metabolite contribution of the bacteria in the aquatic niches where Ae. aegypti larvae develop. An analysis of 32 mosquito-associated bacterial genomes, including Klebsiella, allowed us to identify gene clusters involved in primary metabolic pathways. From them, we inferred metabolites that could impact larval development (e.g., spermidine), as well as influence the quality assessment of a breeding site by a gravid female (e.g., putrescine), if produced by bacteria in the water. We also detected significant variance in metabolite presence profiles between water samples representing a decoupled oviposition event (oviposition by single females and manually deposited eggs) versus a control where no mosquito interactions occurred (PERMANOVA: p < 0.05; R2 = 24.64% and R2 = 30.07%). Five Klebsiella metabolites were exclusively linked to water samples where oviposition and development occurred. These data suggest metabolomics can be applied to identify compounds potentially used by female Ae. aegypti to evaluate the quality of a breeding site. Elucidating the physiological mechanisms by which the females could integrate these sensory cues while ovipositing constitutes a growing field of interest, which could benefit from a more depurated list of candidate molecules.

Oviposition site selection in mosquitoes : the role of conspecific larvae, heterospecific larvae and microbes

“…aegypti may also contribute to oviposition site preference. Breeding sites showing signs of high levels of microbial growth, specifically microbes inoculated during oviposition [51][52][53][54], and associated detritus [55][56][57] that have accumulated during conspecific larval development, provide a rich, abundant larval food source, which reduces the potential competition between established and newly hatched larvae [58]. Gravid mosquitoes ovipositing in temporary waters, such as Ae.…”

Egg-laying by female Aedes aegypti shapes the bacterial communities of breeding sites

“…These findings provide solid grounds to build upon and improve our knowledge of how endo and ecto microbiomes may be critical when addressing their links to host phenotypes through the lens of niche construction theory. Other layers of information may be relevant to improve this take, as the metabolite profile of breeding sites also reflects the act of oviposition and development [ 61 ]. Besides, oviposition by several females responding to bacterially-emitted volatile organic compounds may contribute other symbionts to this community-shaping process ongoing in breeding sites [ 62 ].…”

Differential Hatching, Development, Oviposition, and Longevity Patterns among Colombian Aedes aegypti Populations

“…For example, bacteria present in breeding sites and the metabolites they produce are essential for Ae. aegypti egg hatching [ 108 , 109 ] and eggs infected with Wolbachia show delayed embryo development, delayed eggshell formation, and a diminished egg hatch rate [ 110 , 111 , 112 ]. It has also been determined that gut-associated bacteria are necessary for egg production in Ae.…”