Hidden palette: exploring the role of microbes on avian plumage coloration

Authors: Kartikey Sharma, Marcella Biaz, Victoria Gates

SUNY Campus: SUNY Buffalo

Presentation Type: Poster

Location: Old Union Hall

Presentation #: 41

Timeslot: Session D 3:00-4:00 PM

Abstract: Birds must rely on environmental sources to attain the yellow, orange, and red carotenoid pigments in their feathers. However, bacterial carotenoids have been largely overlooked as a source of plumage pigments. Previous research has shown that bacterial taxa predicted to encode carotenoid biosynthesis genes (e.g., Sphingomonas) are positively associated with plumage color, suggesting a potential link between the avian gut microbiome, genetics, and phenotype. In this study, we are testing the hypothesis that birds utilize bacterial carotenoids to color their plumage. For this project, we focused on a group of colorful birds – the parulid warblers. We isolated unique bacteria from wild-derived fecal samples of five warbler and two non-warbler species on selective (for Sphingomonas spp.) and non-selective media. From 19 individual hosts, 109 morphologically unique colonies were isolated. Pigmented isolates were subjected to pigment extraction and absorbance analysis to characterize pigment profiles within and across host species. We identified four unique pigment profiles among our isolates with absorbance wavelengths between 400-550 nm, suggesting that the avian gut microbiome synthesizes multiple types of carotenoids. We amplified the 16S rRNA gene and used nanopore sequencing to taxonomically identify these bacteria. For taxa known or predicted to synthesize carotenoids, we will analyze their genomes to investigate carotenoid biosynthesis pathways. Our results illuminate the diversity and function of bacteria in bird GMs, providing novel insight into the role of bacteria on evolution in birds.