A draft genome of the honey bee trypanosomatid parasite Crithidia mellificae.

Charles Runckel,Joseph Derisi,Michelle L Flenniken,Mauricio Martins Rodrigues

doi:10.1371/journal.pone.0095057

Charles Runckel, Joseph Derisi + Show 2 more

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https://doi.org/10.1371/journal.pone.0095057

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Abstract

Since 2006, honey bee colonies in North America and Europe have experienced increased annual mortality. These losses correlate with increased pathogen incidence and abundance, though no single etiologic agent has been identified. Crithidia mellificae is a unicellular eukaryotic honey bee parasite that has been associated with colony losses in the USA and Belgium. C. mellificae is a member of the family Trypanosomatidae, which primarily includes other insect-infecting species (e.g., the bumble bee pathogen Crithidia bombi), as well as species that infect both invertebrate and vertebrate hosts including human pathogens (e.g.,Trypanosoma cruzi, T. brucei, and Leishmania spp.). To better characterize C. mellificae, we sequenced the genome and transcriptome of strain SF, which was isolated and cultured in 2010. The 32 megabase draft genome, presented herein, shares a high degree of conservation with the related species Leishmania major. We estimate that C. mellificae encodes over 8,300 genes, the majority of which are orthologs of genes encoded by L. major and other Leishmania or Trypanosoma species. Genes unique to C. mellificae, including those of possible bacterial origin, were annotated based on function and include genes putatively involved in carbohydrate metabolism. This draft genome will facilitate additional investigations of the impact of C. mellificae infection on honey bee health and provide insight into the evolution of this unique family.

Highlights

The western honey bee (Apis mellifera) is an important pollinator of numerous economically important agricultural crops as well as plant species that increase the biodiversity of both agricultural and non-agricultural landscapes
Comparison of the glyceraldehyde 3-phosphate dehydrogenase (GAPDH) gene from this strain determined that the nucleotide sequence over this region was identical to the BruceSD_T17 strain (JF423199) previously described [5], and shared in 99.8% identity with additional C. mellificae GAPDH sequences deposited in the NCBI database (AB716357, AB745489) (Figure S1)
Characteristic features of trypanosomatids include the presence of a single flagellum and a kinetoplast, which is a structure containing a DNA network consisting of multiple copies of the mitochondrial genome

Summary

Introduction

The western honey bee (Apis mellifera) is an important pollinator of numerous economically important agricultural crops (e.g., almonds, apples, melons) as well as plant species that increase the biodiversity of both agricultural and non-agricultural landscapes. Crithidia mellificae is a trypanosomatid parasite of Apis mellifera that was first described in Australian bees in 1967 [4]. We determined that Crithidia mellificae infections were strongly associated with Nosema ceranae and bacterial (Spiroplasma spp.) infections in our sample cohort [5]. This and other recent studies have resulted in a renewed interest in this pathogen. Additional studies are required to determine the prevalence of C. mellificae infections of the eastern honey bee (Apis ceranae)

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