Graduate student Drexel University Holmes, Pennsylvania
Animals, including insects, are unable to synthesize several essential nutrients like the eight B-vitamins. Having to rely primarily on diet for sufficient acquisition, a subset of the world’s insects are proposed to acquire B-vitamins due to the biosynthetic capacities of their microbial endosymbionts. Here, the relationship between insect nutritional needs and encoded symbiont metabolism was studied. We used previously estimated insect requirements in percent dry weight for seven B-vitamins alongside newly compiled average quantities of these B-vitamins in varying insect foods, including seeds, fruit, phloem sap, pollen, leaves, wood, and blood. We obtained FastA formatted proteins from the genomes of obligate symbionts found across insects consuming the above diets across separately derived symbiont lineages.Using the BLAST-KOALA program, KEGG ortholog (KO) numbers were assigned to symbiont proteins, which were cross-referenced against the proteins encoding the steps for the seven B-vitamin biosynthesis pathways. Our statistics show only occasional, and modest correlations between capacities for symbiont B-vitamin synthesis and host nutritional needs. Despite this, the common nature of B-vitamin synthesis among many symbionts, and the rarity of obligate symbioses in insects with more vitamin-rich diets like leaves and pollen support a broader cause-and-effect relationship between host nutritional need and symbiosis. With similar studies on essential amino acids, we will further assess the relationship between symbiont metabolism and dietary need.
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