Vairimorpha necatrix BM

Category
Microsporidia
Phylum
Microsporidia
Class
-
Order
Pansporoblastina
Family
Burenellidae
Genus
Vairimorpha
Species
necatrix
Strain
BM
Host
Silkworm
Status
In Progress
Source
SKLSGB, SWU

Vairimorpha necatrix BM (VnBM), ever named Vairimorpha sp. BM, were isolated from silkworm in Shandong Province, China. The size of V. necatrix BM spore is 3.4 μm x 1.6 μm (Fig. 1C) [1].
The V. necatrix BM can infect nearly all tissues of silkworm (Fig. 1B), but the ovary and testis.  No V. necatrix BM spore has been found in silkworm eggs, that is the V. necatrix BM has not been found that can be vertically transmitted to next generation of silkworm [2]. This is quite different to Nosema bombycis which can be vertically transmitted.
V. necatrix BM infected silkworms
A
V. necatrix BM infected silkworm tissues
B
Spores of V. necatrix BM
C
Fig. 1 V. necatrix BM infected sillworm (A), silkworm tissues (B) and V. necatrix BM spores (C).
The nuclear of V. necatrix BM spore is dikaryotic (Fig. 2A) and is composed of at least six chromosomes (Fig. 2B) [1].  Phylogenetic analysis showed that V. necatrix BM is close to Vairimorpha necatrix DQ996241 (Fig. 3) [1].
Ultra structure of V. necatrix BM
A
The karyotype of V. necatrix BM nuclear
B
Fig. 2 Ultra structure (A) and karyotype (B) of V. necatrix BM spores.
Phylogeny of V. necatrix BM
Fig. 3 Phylogeny of V. necatrix BM [1].
The genome sequencing of Vairimorpha necatrix BM is in progress.

References:

  1. Liu H, Pan G, Li T, Zhou Z, et al. Ultrastructure, chromosomal karyotype, and molecular phylogeny of a new isolate of microsporidian Vairimorpha sp. BM (Microsporidia, Nosematidae) from Bombyx mori in China. Parasitol Res, 2012, 110(1): 205-210. [PubMed]
  2. Bo Luo, Handeng Liu, Guoqing Pan, Tian Li, Zeng Li, Xiaoqun Dang, Tie Liu, Zeyang Zhou. Morphological and molecular studies of Vairimorpha necatrix BM, a new strain of the microsporidium V. necatrix (microsporidia, burenellidae) recorded in the silkworm, Bombyx mori. Exp Parasitol. 2014, pii: S0014-4894(14)00115-5. doi: 10.1016/j.exppara.2014.05.001. [Epub ahead of print] [PubMed]