wolbachia – a heritable endosymbiont patricia sidelsky symbiosis

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Wolbachia – a Heritable Wolbachia – a Heritable Endosymbiont Endosymbiont Patricia Sidelsky Patricia Sidelsky Symbiosis Symbiosis http://tools.neb.com/wolbachia /

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Page 1: Wolbachia – a Heritable Endosymbiont Patricia Sidelsky Symbiosis

Wolbachia – a Heritable Wolbachia – a Heritable EndosymbiontEndosymbiont

Patricia SidelskyPatricia Sidelsky

SymbiosisSymbiosis

http://tools.neb.com/wolbachia/

Page 2: Wolbachia – a Heritable Endosymbiont Patricia Sidelsky Symbiosis

WolbachiaWolbachia

Classified in a monophyletic Classified in a monophyletic clade in Domain Bacteriaclade in Domain Bacteria

A member of A member of Alphaproteobacteria – Alphaproteobacteria – Related to RickettsiaRelated to Rickettsia

Sequencing of 16sRNA Sequencing of 16sRNA connects Wolbachia to connects Wolbachia to Ehrlichia and RickettsiaEhrlichia and Rickettsia

16srRNA sequences used to 16srRNA sequences used to determine relationships determine relationships between Rickettsiabetween Rickettsia

Estimated to infect 15-20% Estimated to infect 15-20% of arthropods. New estimates of arthropods. New estimates include as many as 50% of include as many as 50% of insect speciesinsect species

Broad host range – Insects, Broad host range – Insects, isopods, mites, and isopods, mites, and arachnids. They have been arachnids. They have been isolated from crustaceans. isolated from crustaceans. More recently found in More recently found in NematodesNematodes

Manipulate the reproduction Manipulate the reproduction in their hosts in a number of in their hosts in a number of unusual waysunusual ways

Page 3: Wolbachia – a Heritable Endosymbiont Patricia Sidelsky Symbiosis

http://www.bacterialphylogeny.com/ branching_order_al...

Page 4: Wolbachia – a Heritable Endosymbiont Patricia Sidelsky Symbiosis

Host - EndosymbiontHost - Endosymbiont Wolbachia are found in the Wolbachia are found in the

reproductive tissues of their hostsreproductive tissues of their hosts

The bacterial obligatory The bacterial obligatory endosymbionts are passed endosymbionts are passed vertically in the cytoplasm of the vertically in the cytoplasm of the eggs of their hostseggs of their hosts

The Wolbachia affects sex The Wolbachia affects sex determining factors in insects – determining factors in insects – affects the sex of the insect affects the sex of the insect progenyprogeny

The host exerts population The host exerts population control of bacteriacontrol of bacteria

A force in speciation in A force in speciation in arthropodsarthropods

Viewed as a possibility for the Viewed as a possibility for the evolution of insectsevolution of insects

Wolbachia infected ovaries of insect host

Amy Hise, Science

Page 5: Wolbachia – a Heritable Endosymbiont Patricia Sidelsky Symbiosis

Wolbachia and ReproductionWolbachia and Reproduction

Vertical transmission – Vertical transmission – cytoplasmic inheritancecytoplasmic inheritance

Causes male killing and Causes male killing and sterility in malessterility in males

Induces parthenogenesisInduces parthenogenesis

Cytoplasmic Cytoplasmic

incompatability( conflict incompatability( conflict between cytoplasmic and between cytoplasmic and nuclear components)nuclear components)

Insect egg containing Wolbachia

http://www.rochester.edu/.../ images/Wolb_egg.jpg

Page 6: Wolbachia – a Heritable Endosymbiont Patricia Sidelsky Symbiosis

Symbiont related Sexual Symbiont related Sexual AnomaliesAnomalies

ThelytokyThelytoky occurs in occurs in Trichogramma waspsTrichogramma wasps

In wasps there is a In wasps there is a haplofiploid situation with haplofiploid situation with males haploid and females males haploid and females diploid.diploid.

Virgin Females produce Virgin Females produce diploid females without diploid females without fertilization. The n( haploid) fertilization. The n( haploid) is converted to 2n( diploid)is converted to 2n( diploid)

This occurs early in the first This occurs early in the first mitotic divisionmitotic division

FeminizationFeminization of males of males

Occurs in IsopodsOccurs in Isopods

Suppresses the androgenic Suppresses the androgenic gland and causes males to gland and causes males to become functional femalesbecome functional females

http://www.biconet.com/flies/FC3.html http://www.biodiversity.org.uk/.../images/isopods.jpg

Page 7: Wolbachia – a Heritable Endosymbiont Patricia Sidelsky Symbiosis

Cytoplasmic Incompatability and Cytoplasmic Incompatability and vertical transmissionvertical transmission

If both male and female If both male and female insects are infected with insects are infected with Wolbachia – the progeny will Wolbachia – the progeny will be infectedbe infected

If the female is infected and If the female is infected and the male is not infected, the the male is not infected, the progeny will all be infected.progeny will all be infected.

If the female is not infected If the female is not infected and the male is infected and the male is infected there will not be any progenythere will not be any progeny http://www.cdc.gov/ncidod/eid/vol4no4/beard6t.gif

Page 8: Wolbachia – a Heritable Endosymbiont Patricia Sidelsky Symbiosis

Examples of symbiont – host interactionsExamples of symbiont – host interactions

Male killing mechanism has been studied in two species of insectMale killing mechanism has been studied in two species of insect In In Adalia bipunctataAdalia bipunctata and and Acraea encedon Acraea encedon the presence of Wolbachia the presence of Wolbachia

halves the hatch size and changes the female/male ratiohalves the hatch size and changes the female/male ratio Microbial nature of infection has been verified by treatment with rifampin Microbial nature of infection has been verified by treatment with rifampin

and sulphamethoxazoleand sulphamethoxazole After treatment with antibiotics the hatch size returns to normal and the After treatment with antibiotics the hatch size returns to normal and the

with a normal sex ratiowith a normal sex ratio Condition can be artificially induced by injection of macerated infected Condition can be artificially induced by injection of macerated infected

insect into pupae of uninfected ( Hurst et al)insect into pupae of uninfected ( Hurst et al)

Adalia bipunctata – http :bugguide.net/ node/view/13976 Acraea encedon- www2.nrm.se/.../e/ acraea_encedonfumosa.html

Page 9: Wolbachia – a Heritable Endosymbiont Patricia Sidelsky Symbiosis

Why Male Killing ?Why Male Killing ? Reduces competition for food ( H)Reduces competition for food ( H)

Reduces cannibalism in siblings (H)Reduces cannibalism in siblings (H)

Improves female fitness for breeding- selective advantage Improves female fitness for breeding- selective advantage (H)(H)

Insures propagation of Wolbachia endosymbionts to future Insures propagation of Wolbachia endosymbionts to future generations ( S + H)generations ( S + H)

H= Host selective advantage S= Symbiont selective advantage

Page 10: Wolbachia – a Heritable Endosymbiont Patricia Sidelsky Symbiosis

Mechanism of Action Bacterial modification of Bacterial modification of

sperm by bacterial sperm by bacterial interactionsinteractions

Bacteria present in testes Bacteria present in testes interact with DNA binding interact with DNA binding proteins – Theseproteins – These

may be similar to H1, may be similar to H1, histoneshistones

The same bacterial strain The same bacterial strain must be present in the must be present in the female in order to rescue the female in order to rescue the eggegg

Mitotic defects appear in the Mitotic defects appear in the early divisions of the early divisions of the fertilized egg( during fertilized egg( during cleavage)cleavage)

HI – Protein database

Page 11: Wolbachia – a Heritable Endosymbiont Patricia Sidelsky Symbiosis

Wolbachia – Evidence for specificity of infection

PCR for 16sRNA from infected PCR for 16sRNA from infected lineslines

Product purified and ligated Product purified and ligated into pGEM vectorinto pGEM vector

Plasmids were transformed Plasmids were transformed into DH5ainto DH5a

Colonies with insert were Colonies with insert were detecteddetected

39 /42 positive for Wolbachia 39 /42 positive for Wolbachia insert and not other bacteria insert and not other bacteria 16sRNA16sRNA

Transformants are recognized by blue color on agar plate

Page 12: Wolbachia – a Heritable Endosymbiont Patricia Sidelsky Symbiosis

Wolbachia and geneticsWolbachia and genetics Genome recently sequencedGenome recently sequenced

Loss of genes due to obligatory Loss of genes due to obligatory nature of relationship between nature of relationship between bacteria and hostbacteria and host

Loss of genes over time due to Loss of genes over time due to dependency on hostdependency on host

Many repetitive elements and Many repetitive elements and insertion sequences in the insertion sequences in the genomegenome

Imply high level of intergenomic Imply high level of intergenomic and intragenomic recombinationand intragenomic recombination

Genomic map of Wolbachia

NCBI

http://www.ncbi.nlm.nih.gov

Page 13: Wolbachia – a Heritable Endosymbiont Patricia Sidelsky Symbiosis

Genetics of WolbachiaGenetics of Wolbachia Wolbachian genome consists of one Wolbachian genome consists of one

circular chromosomecircular chromosome

1.26Mbp – 1195 proteins – GC content 35%

Contains genes withContains genes with

Ankyrin repeats – Ankyrins connect Ankyrin repeats – Ankyrins connect endosymbionts to the cell cytoskleton endosymbionts to the cell cytoskleton which is an adaptation for which is an adaptation for intracellular existenceintracellular existence

Type Four Secretion System – Type Four Secretion System – required for persistence of required for persistence of endosymbiont in host – conserved in endosymbiont in host – conserved in RickettsiaRickettsia

Female Drosophila melanogaster – laying egg

P. Sidelsky – Motic Camera

Page 14: Wolbachia – a Heritable Endosymbiont Patricia Sidelsky Symbiosis

Lateral Transfer of GenesLateral Transfer of Genes Evidence of lateral( horizontal) Evidence of lateral( horizontal)

transfer of genes in Wolbachia transfer of genes in Wolbachia species in species in Drosophila Drosophila melanogastermelanogaster and and Nasonia Nasonia vitripennis.vitripennis.

Drosophila and Nasonia Drosophila and Nasonia can can maintain infection by two strains maintain infection by two strains of Wolbachiaof Wolbachia

Exchange between bacteria that Exchange between bacteria that coinfect in the same cellscoinfect in the same cells

( density dependent)( density dependent)

Exchange between Exchange between endosymbiont and host( gene endosymbiont and host( gene loss)loss)

IS sequences in Wolbachia IS sequences in Wolbachia suggest Bacteriophage transfer suggest Bacteriophage transfer between Wolbachia strains.between Wolbachia strains.

Recent research has detected 3 Recent research has detected 3 prophage sequences in the prophage sequences in the Wolbachia genome.Wolbachia genome.

( Wu et al)( Wu et al)

Page 15: Wolbachia – a Heritable Endosymbiont Patricia Sidelsky Symbiosis

Importance of studyImportance of study Wolbachia does not infect Wolbachia does not infect

humans – studying Wolbachia humans – studying Wolbachia can lead to a better can lead to a better understanding of Rickettsial – understanding of Rickettsial – host interactions for medical host interactions for medical applciationsapplciations

Understanding Wolbachia can Understanding Wolbachia can lead to vector control in lead to vector control in infections such as Rocky infections such as Rocky Mountain Spotted FeverMountain Spotted Fever

( Rickettsia and tic)( Rickettsia and tic)

Since Wolbachia infects diverse Since Wolbachia infects diverse species of insects including species of insects including beetles, fruit flies, and beetles, fruit flies, and mosquitoes, it could be mosquitoes, it could be evaluated for a form of biological evaluated for a form of biological controlcontrol

Used as a model to study Used as a model to study speciationspeciation

Mediterranean Fruit Fly

http://creatures.ifas.ufl.edu/fruit/mediterranean_fruit_fly.htm

Page 16: Wolbachia – a Heritable Endosymbiont Patricia Sidelsky Symbiosis

Wolbachia and River BlindnessWolbachia and River Blindness

Wolbachia has also been identified in Wolbachia has also been identified in filarial wormsfilarial worms

( Nematoda)( Nematoda)

One of these worms causes One of these worms causes Riverblindness(Onchoceriasis) Riverblindness(Onchoceriasis)

Wolbachia provides metabolic Wolbachia provides metabolic support through many pathwayssupport through many pathways

for the worm.for the worm.

Contributes to inflammatory Contributes to inflammatory responsesresponses

Instead of antihelminth drug Instead of antihelminth drug protocols – will antibiotics be a protocols – will antibiotics be a cure??????cure??????

http://tools.neb.com/wolbachia/

Page 17: Wolbachia – a Heritable Endosymbiont Patricia Sidelsky Symbiosis

ReferencesReferences

Anderson,Cort and Timothy Karr. Wolbachia:Evolutionary Novelty in a Rickettsial Anderson,Cort and Timothy Karr. Wolbachia:Evolutionary Novelty in a Rickettsial Bacteria. BMC Evolutionary Biology, 2001:1-10.Bacteria. BMC Evolutionary Biology, 2001:1-10.

Huigens,M.E. On the Evolution of Wolbachia Induced Parthenogenesis in Huigens,M.E. On the Evolution of Wolbachia Induced Parthenogenesis in Trichogramma Wasps.Trichogramma Wasps.

http://www.gcw.nl/dissertations/3389/dis3389.pdfhttp://www.gcw.nl/dissertations/3389/dis3389.pdfHurst, Gregory et al. Male-Killing Wolbachia in Two Species of Insect.Hurst, Gregory et al. Male-Killing Wolbachia in Two Species of Insect.National Center for Biotechnology Information – ncbi. http://www.ncbi.nlm.nih.gov/National Center for Biotechnology Information – ncbi. http://www.ncbi.nlm.nih.gov/Johanowicz,Denise et Marjorie Foy.Wolbachia Endosymbionts. Florida Johanowicz,Denise et Marjorie Foy.Wolbachia Endosymbionts. Florida

Entomologist.1998: 310-316.Entomologist.1998: 310-316.Protein Data Bank - http://www.rcsb.org/pdb/Protein Data Bank - http://www.rcsb.org/pdb/Rigaud, T., Juchault, P., and Mocquard, J. P. 1991. Experimental study of the sex Rigaud, T., Juchault, P., and Mocquard, J. P. 1991. Experimental study of the sex

ratio of broods in terrestrial Crustacea ratio of broods in terrestrial Crustacea Armadillium vulgare.Armadillium vulgare. Possible implications Possible implications in natural populations. in natural populations. J. Evol. Biol. J. Evol. Biol. 1991: 603 - 607. 1991: 603 - 607.

Sun,Ling. Et al. Gene Organization in the dnaA Region of Wolbachia. Jornal of Sun,Ling. Et al. Gene Organization in the dnaA Region of Wolbachia. Jornal of Bacterioology. 199.18115):4708-4710.Bacterioology. 199.18115):4708-4710.

Page 18: Wolbachia – a Heritable Endosymbiont Patricia Sidelsky Symbiosis

References( con)References( con)Wernegreen,Jennifer Endosymbiosis: Lessons in Conflict Resolution. Plos Wernegreen,Jennifer Endosymbiosis: Lessons in Conflict Resolution. Plos

Biology. March 2004, 2:307-311.Biology. March 2004, 2:307-311.Werren,John H. Biology of Wolbachia. Annual Review of Entomology. Werren,John H. Biology of Wolbachia. Annual Review of Entomology.

1997.42:587-609.1997.42:587-609.Werren, John H. and Leo Beukboom. Sex Determination, Sex Ratios, and Werren, John H. and Leo Beukboom. Sex Determination, Sex Ratios, and

Genetic Conflict.Annual Review of Ecological Systematics. 1998,29:233-Genetic Conflict.Annual Review of Ecological Systematics. 1998,29:233-261.261.

Werren, John H. and David Windsor. Wolbachia Infection Frequencies in Werren, John H. and David Windsor. Wolbachia Infection Frequencies in Insects: Evidence of a Global Equilibrium. Proceedings of the Royal Insects: Evidence of a Global Equilibrium. Proceedings of the Royal Society. 200 267: 1277-1285Society. 200 267: 1277-1285

Werren, John H. Wolbachia Run Amok. Proceedings of the National Werren, John H. Wolbachia Run Amok. Proceedings of the National Academy of Science. 1997. 92: 11154-11155Academy of Science. 1997. 92: 11154-11155

Wu,Martin et al. Phylogenomics of the Reproductive Parasite Wu,Martin et al. Phylogenomics of the Reproductive Parasite Wolbachia Wolbachia pipientispipientis wMeI: A Streamlined Genome Overrun by Mobile Genetic wMeI: A Streamlined Genome Overrun by Mobile Genetic Elements. Plos Biology. 2004,2:327-333.Elements. Plos Biology. 2004,2:327-333.