The genome sequence and gene prediction of Mitosporidium
daphniae UPG3 have not been determined by the Joint Genome
Institute (JGI), but were downloaded from NCBI
on May 28, 2018. In order to allow comparative analyses with other
fungal genomes sequenced by the JGI, a copy of this genome is
incorporated into Mycocosm. Please
note that this copy of the genome is not maintained by NCBI and is
therefore not automatically updated. JGI tools were used to
automatically annotate predicted proteins.
Mitosporidium daphniae is an obligate endoparasite known
only from the lower midgut epithelium of the water flea Daphnia
magna in north-western Europe. The species was shown by Dieter
Ebert’s lab to have a negative fitness effect on the host
(Refardt and Ebert 2012) and was known for a long time as unknown
gut parasite 3 (UGP3) because of its uncertain phylogenetic
affinities. Morphologically the species is similar to the highly
reduced Microsporidia endoparasites, but has a minimal polar tube
(infection structure) relative to core Microsporidia. Initially,
rRNA gene sequences allied the parasite with the enigmatic group of
fungi related to Microsporidia known as Cryptomycota (or Rozellids
or Rozellomycota) that are by and large only known from
environmental DNA sequences (Richards et al. 2017). Haag et al.
(2014) sequenced the genome of M. daphniae and found that
it is contains similarities to both Rozella allomycis
(Cryptomycota), such as ability to generate energy through
oxidative phosphorylation and a very similar mitochondrial genome.
On the other hand, M. daphniae has considerably fewer
genes than R. allomycis and has reduced DNA repair and
recombination proteins and an elevated rate of nucleotide
substitution as observed in core Microsporidia. M.
daphniae is variously considered as a Cryptomycotan or
Microsporidian, and it is clear that the lines between these two
groups are blurred because of species like M. daphniae
which possess traits intermediate between both groups (Bass et al.
2018).
Genome Reference(s)
Haag KL, James TY, Pombert JF, Larsson R, Schaer TM, Refardt D, Ebert D
Evolution of a morphological novelty occurred before genome compaction in a lineage of extreme parasites.
Proc Natl Acad Sci U S A. 2014 Oct 28;111(43):15480-5. doi: 10.1073/pnas.1410442111
Other References
- Bass, D. , L. Czech, B. A. Williams, C. Berney, M. Dunthorn, F. Mahé, G. Torruella, G. D. Stentiford, and T. A. Williams. (2018). Clarifying the Relationships between Microsporidia and Cryptomycota. J. Eukaryot. Microbiol., 65: 773-782. doi: 10.1111/jeu.12519
- Refardt, D., and D. Ebert. (2012). The impact of infection on host competition and its relationship to parasite persistence in a Daphnia microparasite system. Evol. Ecol. 26: 95-107. doi: 10.1007/s10682-011-9487-5
- Richards, T. A., G. Leonard, and J. G. Wideman. (2017). What Defines the “Kingdom” Fungi?, p 57-77. In Heitman J, Howlett B, Crous P, Stukenbrock E, James T, Gow N (ed), The Fungal Kingdom. ASM Press, Washington, DC. doi: 10.1128/microbiolspec.FUNK-0044-2017