PMID- 32801177
OWN - NLM
STAT- MEDLINE
DCOM- 20201211
LR  - 20220518
IS  - 1098-5336 (Electronic)
IS  - 0099-2240 (Print)
IS  - 0099-2240 (Linking)
VI  - 86
IP  - 20
DP  - 2020 Oct 1
TI  - Tissue Tropisms and Transstadial Transmission of a Rickettsia Endosymbiont in the 
      Highland Midge, Culicoides impunctatus (Diptera: Ceratopogonidae).
LID - 10.1128/AEM.01492-20 [doi]
LID - e01492-20
AB  - Rickettsia is a genus of intracellular bacteria which can manipulate host 
      reproduction and alter sensitivity to natural enemy attack in a diverse range of 
      arthropods. The maintenance of Rickettsia endosymbionts in insect populations can 
      be achieved through both vertical and horizontal transmission routes. For 
      example, the presence of the symbiont in the follicle cells and salivary glands 
      of Bemisia whiteflies allows Belli group Rickettsia transmission via the germ 
      line and plants, respectively. However, the transmission routes of other 
      Rickettsia bacteria, such as those in the Torix group of the genus, remain 
      underexplored. Through fluorescence in situ hybridization (FISH) and transmission 
      electron microscopy (TEM) screening, this study describes the pattern of Torix 
      Rickettsia tissue tropisms in the highland midge, Culicoides impunctatus 
      (Diptera: Ceratopogonidae). Of note is the high intensity of infection of the 
      ovarian suspensory ligament, suggestive of a novel germ line targeting strategy. 
      Additionally, localization of the symbiont in tissues of several developmental 
      stages suggests transstadial transmission is a major route for ensuring 
      maintenance of Rickettsia within C. impunctatus populations. Aside from providing 
      insights into transmission strategies, the presence of Rickettsia bacteria in the 
      fat body of larvae indicates potential host fitness and vector capacity impacts 
      to be investigated in the future.IMPORTANCE Microbial symbionts of disease 
      vectors have garnered recent attention due to their ability to alter vectorial 
      capacity. Their consideration as a means of arbovirus control depends on symbiont 
      vertical transmission, which leads to spread of the bacteria through a 
      population. Previous work has identified a Rickettsia symbiont present in several 
      species of biting midges (Culicoides spp.), which transmit bluetongue and 
      Schmallenberg arboviruses. However, symbiont transmission strategies and host 
      effects remain underexplored. In this study, we describe the presence of 
      Rickettsia in the ovarian suspensory ligament of Culicoides impunctatus Infection 
      of this organ suggests the connective tissue surrounding developing eggs is 
      important for ensuring vertical transmission of the symbiont in midges and 
      possibly other insects. Additionally, our results indicate Rickettsia 
      localization in the fat body of Culicoides impunctatus As the arboviruses spread 
      by midges often replicate in the fat body, this location implies possible 
      symbiont-virus interactions to be further investigated.
CI  - Copyright (c) 2020 Pilgrim et al.
FAU - Pilgrim, Jack
AU  - Pilgrim J
AUID- ORCID: 0000-0002-2941-1482
AD  - Institute of Infection, Veterinary and Ecological Sciences, Faculty of Health and 
      Life Sciences, University of Liverpool, Liverpool, United Kingdom 
      jack.pilgrim@liverpool.ac.uk.
FAU - Siozios, Stefanos
AU  - Siozios S
AUID- ORCID: 0000-0002-1104-7061
AD  - Institute of Infection, Veterinary and Ecological Sciences, Faculty of Health and 
      Life Sciences, University of Liverpool, Liverpool, United Kingdom.
FAU - Baylis, Matthew
AU  - Baylis M
AD  - Institute of Infection, Veterinary and Ecological Sciences, Faculty of Health and 
      Life Sciences, University of Liverpool, Liverpool, United Kingdom.
AD  - Health Protection Research Unit in Emerging and Zoonotic Infections, Liverpool, 
      United Kingdom.
FAU - Hurst, Gregory D D
AU  - Hurst GDD
AUID- ORCID: 0000-0002-7163-7784
AD  - Institute of Infection, Veterinary and Ecological Sciences, Faculty of Health and 
      Life Sciences, University of Liverpool, Liverpool, United Kingdom.
LA  - eng
GR  - BBS/E/I/00001701/BB_/Biotechnology and Biological Sciences Research 
      Council/United Kingdom
GR  - BB/M011186/1/BB_/Biotechnology and Biological Sciences Research Council/United 
      Kingdom
GR  - BB/M012441/1/BB_/Biotechnology and Biological Sciences Research Council/United 
      Kingdom
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20201001
PL  - United States
TA  - Appl Environ Microbiol
JT  - Applied and environmental microbiology
JID - 7605801
SB  - IM
MH  - Animals
MH  - Ceratopogonidae/*microbiology
MH  - Female
MH  - In Situ Hybridization, Fluorescence
MH  - Insect Vectors/*microbiology
MH  - Male
MH  - Phylogeny
MH  - Rickettsia/*physiology
MH  - *Symbiosis
MH  - Tropism
PMC - PMC7531967
OTO - NOTNLM
OT  - Culicoides
OT  - Rickettsia
OT  - arthropod vectors
OT  - microbial ecology
OT  - symbiosis
OT  - tissue tropisms
OT  - vector biology
EDAT- 2020/08/18 06:00
MHDA- 2020/12/15 06:00
PMCR- 2020/10/01
CRDT- 2020/08/18 06:00
PHST- 2020/06/24 00:00 [received]
PHST- 2020/07/31 00:00 [accepted]
PHST- 2020/08/18 06:00 [pubmed]
PHST- 2020/12/15 06:00 [medline]
PHST- 2020/08/18 06:00 [entrez]
PHST- 2020/10/01 00:00 [pmc-release]
AID - AEM.01492-20 [pii]
AID - 01492-20 [pii]
AID - 10.1128/AEM.01492-20 [doi]
PST - epublish
SO  - Appl Environ Microbiol. 2020 Oct 1;86(20):e01492-20. doi: 10.1128/AEM.01492-20. 
      Print 2020 Oct 1.