title: Characterization of Nosema ceranae Genetic Variants from Different Geographic Origins.
abstract: In recent years, large-scale colony losses of honey bees (Apis mellifera) have been reported and the infection with the microsporidia Nosema ceranae has been involved. However, the effect of N. ceranae at the colony level and its role in colony losses vary in different geographic areas. This difference may be related to the presence of multiple N. ceranae genetic variants resulting in different biological consequences. In this study, we analyzed the genetic diversity of 75 N. ceranae samples obtained from 13 countries and Hawaii through inter-sequence single repetition (ISSR) and evaluated if two of these genetic variants triggered different immune responses when infecting Apis mellifera iberiensis. The genetic diversity analysis showed that 41% of the samples had the same DNA amplification pattern, including samples from most European countries except Spain, while the remaining samples showed high variability. Infection assays were performed to analyze the infection levels and the immune response of bees infected with N. ceranae from Spain and Uruguay. The infected bees presented similar infection levels, and both isolates downregulated the expression of abaecin, confirming the ability of the microsporidia to depress the immune response. Only N. ceranae from Uruguay downregulated the expression level of imd compared to control bees. On the other hand, both genetic variants triggered different expression levels of lysozyme. As imd and lysozyme play important roles in the response to pathogens, these results could reflect differences in the biological consequences of N. ceranae variants in A. mellifera infection.
authors.affiliation: Departamento de Microbiología, Instituto de Investigaciones Biológicas Clemente Estable, Avda. Italia 3318, CP 11600, Montevideo, Uruguay.
authors.forename: B
authors.initials: B
authors.lastname: Branchiccela
authors.affiliation: Departamento de Microbiología, Instituto de Investigaciones Biológicas Clemente Estable, Avda. Italia 3318, CP 11600, Montevideo, Uruguay.
authors.forename: D
authors.initials: D
authors.lastname: Arredondo
authors.affiliation: Bee Pathology Laboratory, Regional Apicultural Center, Guadalajara, Spain.
authors.forename: M
authors.initials: M
authors.lastname: Higes
authors.affiliation: Sección Etología, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay.
authors.forename: C
authors.initials: C
authors.lastname: Invernizzi
authors.affiliation: Bee Pathology Laboratory, Regional Apicultural Center, Guadalajara, Spain.
authors.forename: R
authors.initials: R
authors.lastname: Martín-Hernández
authors.affiliation: Departamento de Ecología y Evolución, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay.
authors.forename: I
authors.initials: I
authors.lastname: Tomasco
authors.affiliation: Departamento de Microbiología, Instituto de Investigaciones Biológicas Clemente Estable, Avda. Italia 3318, CP 11600, Montevideo, Uruguay.
authors.forename: P
authors.initials: P
authors.lastname: Zunino
authors.affiliation: Departamento de Microbiología, Instituto de Investigaciones Biológicas Clemente Estable, Avda. Italia 3318, CP 11600, Montevideo, Uruguay. kantunez03@gmail.com.
authors.forename: K
authors.initials: K
authors.lastname: Antúnez
mesh_terms: D000820:Animal Diseases / Q000382:microbiology; D000818:Animals; D023181:Antimicrobial Cationic Peptides / Q000235:genetics / Q000378:metabolism; D001516:Bees / Q000235:genetics / Q000276:immunology / Q000382:microbiology*; D004271:DNA, Fungal / Q000737:chemistry; D015536:Down-Regulation; D005786:Gene Expression Regulation; D005800:Genes, Fungal / Q000235:genetics; D014644:Genetic Variation; D005843:Geography; D019476:Insect Proteins / Q000235:genetics / Q000378:metabolism; D016881:Microsporidiosis / Q000276:immunology / Q000662:veterinary; D009113:Muramidase / Q000378:metabolism; D016818:Nosema / Q000145:classification / Q000235:genetics* / Q000472:pathogenicity*; D012331:RNA, Fungal / Q000737:chemistry; D060888:Real-Time Polymerase Chain Reaction / Q000379:methods
chemical_list: D023181:Antimicrobial Cationic Peptides; D004271:DNA, Fungal; D019476:Insect Proteins; D012331:RNA, Fungal; C062933:abaecin protein, Apis mellifera; D009113:Muramidase
keywords: Colony losses; Genetic diversity; Immune response; Nosema ceranae