Differences in microbiota between two multilocus lineages of the sugarcane aphid (Melanaphis sacchari) in the continental US

Authors: HOLT, JOCELYN - Texas A&M University; STYER, ALEX - University Of California; WHITE, JENNIFER - University Of Kentucky; Armstrong, John; NIBOUCHE, SAMUEL - Cirad, France; COSTET, LAURENT - Cirad, France; MALACRINO, ANTONINO - The Ohio State University; ANTWI, JOSEPHINE - University Of Maryland; WULLF, JASON - Texas A&M University; PETERSON, GARY - Texas Agrilife Research; MCLAREN, NEAL - University Of The Free State; MEDINA, RAUL - Texas A&M University

Submitted to: Annals of the Entomological Society of America
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/11/2019
Publication Date: 3/16/2020
Citation: Holt, J., Styer, A., White, J., Armstrong, J.S., Nibouche, S., Costet, L., Malacrino, A., Antwi, J., Wullf, J., Peterson, G., McLaren, N., Medina, R. 2020. Differences in microbiota between two multilocus lineages of the sugarcane aphid (Melanaphis sacchari) in the continental US. Annals of the Entomological Society of America. 113(4):257-265. https://doi.org/10.1093/aesa/saaa003.
DOI: https://doi.org/10.1093/aesa/saaa003

Interpretive Summary: We looked at the microbiota, or bacterial and fungal associates found on the surface of sugarcane aphids by using a DNA microarray analysis. Our findings show that there exist two biotypes of the sugarcane aphid and that they both are associated with a completely different group microbiota which is further evidence that they originate from different multi locus lineages. Some of the microbiota identified from both sets of aphids had never been reported associated with any aphid species.

Technical Abstract: The sugarcane aphid (Melanaphis sacchari (Zehntner), SCA) has been considered an invasive pest of sugarcane in the continental U.S. since 1977. Then, in 2013, SCA abruptly became a serious pest of U.S. sorghum and is now a sorghum pest in twenty-two states across the continental U.S. Changes in insect-associated microbial community composition are known to influence host-plant range in aphids. In this study, we assessed whether changes in microbiota composition may explain the SCA outbreak in U.S. sorghum. We characterized the SCA bacterial microbiota on sugarcane and grain sorghum in four U.S. states, using a metabarcoding approach. In addition, we used taxon-specific PCR primers to screen for bacteria commonly reported in aphid species. As anticipated, all SCA harbored the primary aphid symbiont Buchnera aphidicola. Interestingly, none of the facultative bacteria typically associated with aphids (e.g., Arsenophonus, Hamiltonella, Regiella) were present in either the metabarcoding data or PCR screens with the exception of Rickettsiella and Serratia that were detected by metabarcoding at low abundances <1%). However, our metabarcoding detected bacteria not previously identified in aphids (e.g., Arcobacter, Bifidobacterium, Citrobacter, etc.). Lastly, we found microbial host-associated differentiation in aphids that seems to correspond to the genetically distinct aphid lineages that prefer to feed on grain sorghum (MLL-F) and sugarcane (MLL-D).