High levels of genetic diversity in Nosema ceranae within Apis mellifera colonies.
Nosema ceranae is a widespread honeybee parasite, considered to be one of the pathogens involved in the colony losses phenomenon. To date, little is known about its intraspecific genetic variability. The few studies on N. ceranae variation have focused on the subunits of ribosomal DNA, which are not ideal for this purpose and have limited resolution. Here we characterized three single copy loci (Actin, Hsp70 and RPB1) in three N. ceranae isolates from Hungary and Hawaii. Our results provide evidence of unexpectedly high levels of intraspecific polymorphism, the coexistence of a wide variety of haplotypes within each bee colony, and the occurrence of genetic recombination in RPB1. Most haplotypes are not shared across isolates and derive from a few frequent haplotypes by a reduced number of singletons (mutations that appear usually just once in the sample), which suggest that they have a fairly recent origin. Overall, our data indicate that this pathogen has experienced a recent population expansion. The presence of multiple haplotypes within individual isolates could be explained by the existence of different strains of N. ceranae infecting honeybee colonies in the field which complicates, and must not be overlooked, further analysis of host-parasite interactions.
Laboratorio de Patología Apícola, Centro Apícola Regional, JCCM, 19180 Marchamalo, Spain.
Tamara
T
Gómez-Moracho
Departamento de Anatomía Patolóxica e Ciencias Forenses, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Galicia, Spain.
Xulio
X
Maside
Laboratorio de Patología Apícola, Centro Apícola Regional, JCCM, 19180 Marchamalo, Spain.
Raquel
R
Martín-Hernández
Laboratorio de Patología Apícola, Centro Apícola Regional, JCCM, 19180 Marchamalo, Spain.
Mariano
M
Higes
Departamento de Anatomía Patolóxica e Ciencias Forenses, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Galicia, Spain.
Carolina
C
Bartolomé
D000199:Actins / Q000235:genetics; D000818:Animals; D001483:Base Sequence; D001516:Bees / Q000382:microbiology*; D005656:Fungal Proteins / Q000235:genetics; D014644:Genetic Variation; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics; D006239:Haplotypes; D054884:Host-Pathogen Interactions; D008969:Molecular Sequence Data; D009154:Mutation; D016818:Nosema / Q000235:genetics* / Q000502:physiology; D012319:RNA Polymerase II / Q000235:genetics; D017422:Sequence Analysis, DNA / Q000662:veterinary; D013045:Species Specificity
D000199:Actins; D005656:Fungal Proteins; D018840:HSP70 Heat-Shock Proteins; D012319:RNA Polymerase II