Microbiome-derived queuine vitamers underlie tyrosine metabolism and predator avoidance in mosquito larvae

The gut microbiome is a rich source of nutrients that are critical to the development and biology of eukaryotes. Transfer RNAs (tRNAs) are essential components of protein synthesis, and certain chemical modifications of tRNAs depend on the availability of microbiome-derived nutrients. In eukaryotes, the nucleobase queuine (q) or nucleoside queuosine (Q) is salvaged from the microbiome or diet and incorporated into tRNA, where it influences the speed and efficiency of protein synthesis. Here, we examine the role of microbiome-derived Q in mosquito larval development and behavior. When mosquito larvae are grown with a microbiome incapable of synthesizing Q, there is a significant impact on tyrosine levels and downstream processes, which correlate with defects in behavior and cuticle formation. Likely due to effects on movement and behavior, Q-deficient larvae exhibit impaired predator evasion, resulting in increased capture by predaceous beetle larvae. The broad effects of Q-deficiency in mosquito larvae highlight the importance of previously unexplored microbiome-derived nutrients for mosquito physiology and behavior.