Submitted to: Journal of Invertebrate Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/26/2010
Publication Date: 8/4/2010
Citation: Ascunce, M.S., Valles, S.M., Oi, D.H., Shoemaker, D.D., Plowes, R., Gilbert, L., Lebrun, E.G., Sanchez-Arroyo, H., Sanchez-Pena, S. 2010. Molecular diversity of the microsporidium Kneallhazzia solenopsae reveals an expanded host range among fire ants in North America. Journal of Invertebrate Pathology. 105:279-288. Interpretive Summary: Kneallhazia solenopsae is a pathogenic microsporidium of the fire ants Solenopsis invicta and Solenopis richteri that it is currently used for biological control in the USA against these pests. Scientists at the Center for Medical, Agricultural, and Veterinary Entomology, USDA-ARS (Gainesville) and scientists from the University of Texas (Austin), the Instituto de Fitosanidad at Texcoco (Mexico) and the Departamento de Parasitología, Universidad Autónoma Agraria Antonio Narro (Mexico) analyzed the molecular diversity of this pathogen in infected ants from North America including: S. invicta, S. geminata and the hybrid S. geminata x S. xyloni. Understanding the genetic diversity of this microsporidium and the identification of species-specific strains is critical for current biological control plans against fire ants employing this natural enemy.
Technical Abstract: Kneallhazia solenopsae is a pathogenic microsporidium of the fire ants Solenopsis invicta and Solenopis richteri in South America and the USA. In this study we analyzed the presence and molecular diversity of K. solenopsae in fire ants from North and South America. We reported the first empirical evidence for K. solenopsae infection of the tropical fire ant, S. geminata and the S. geminata x S. xyloni hybrids revealing an expanded host range for this microsporidium. We analyzed the molecular diversity at the 16S ribosomal gene in K. solenopsae from the ant hosts S. invicta, S. richteri, S. geminata, and S. geminata/S. xyloni hybrids from North America, Argentina and Brazil. Among the infected colonies, we found a total of twenty-two 16S haplotypes, one of which, widely distributed (WD_1), was identical between S. invicta from the USA and S. geminata from southern Mexico. The 16S phylogenetic reconstructions revealed that K. solenopsae genetic lineages formed two main clades differentiated by p-distance values of 2 to 3%. Multiple K. solenopsae haplotypes per colony were identified suggesting that there is either an incomplete homogenization of the 16S gene cluster or that ant colonies may be infected by multiple strains simultaneously.