Evolution of B Vitamin Synthesis Genes in the Bacterial Endosymbiont Arsenophonus, found in the aphid Obtusicauda coweni (.pdf file)
AUTHOR:
Courtney Covolo
FACULTY: Anna Himler
DEPARTMENT: Biology
The sagebrush (Artemisia tridentata) is the keystone plant of the sagebrush-steppe ecosystem that spans the northwestern United States. The aphid Obtusicauda coweni lives only on sagebrush and feeds on the plant's phloem. Aphids and other insects are home to several bacterial endosymbionts, which can manipulate the reproduction of the insect host, protect it from parasitoids, and prevent heat shock. Bacterial endosymbionts can also produce essential nutrients to supplement the phloem diet of aphids. Arsenophonus and other bacterial endosymbionts can influence insect host evolution and the resulting evolution of the host plant. Endosymbionts also have potential applications in pest control and in the control of insect vector-borne diseases. Our previous research found a relatively high prevalence rate (72%) of the endosymbiont Arsenophonus in O. coweni. One explanation is that Arsenophonus is involved in making B vitamins for the aphid host. Using Polymerase Chain Reaction (PCR), gel electrophoresis, and direct sequencing, our lab examined genes used to make Riboflavin (B2), Biotin (B7), and Folate (B9). We found one gene for each B vitamin: RibA, FolP, and BioA. These genes have a functional reading frame and little to no mutations. This suggests that Arsenophonus can use its B vitamin synthesis genes to benefit the aphid host. In the future we hope to find more functional B vitamin genes within the Arsenophonus genome and establish the location of Arsenophonus using Fluorescence in situ Hybridization (FISH). This research was supported by the M. J. Murdock Charitable Trust grant number SR-201811723, EPSCoRNSF grant number OIA-1826801 and The College of Idaho startup funds to Dr. Himler.
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