Environmental Factors Determining the Epidemiology and Population Genetic Structure of the Group in the Field

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Bacillus thuringiensis (Bt) and its insecticidal toxins are widely exploited in microbial biopesticides and genetically modified crops. Its population biology is, however, poorly understood. Important issues for the safe, sustainable exploitation of Bt include understanding how selection maintains expression of insecticidal toxins in nature, whether entomopathogenic Bt is ecologically distinct from related human pathogens in the Bacillus cereus group, and how the use of microbial pesticides alters natural bacterial populations. We addressed these questions with a MLST scheme applied to a field experiment in which we excluded/added insect hosts and microbial pesticides in a factorial design. The presence of insects increased the density of Bt/B. cereus in the soil and the proportion of strains expressing insecticidal toxins. We found a near-epidemic population structure dominated by a single entomopathogenic genotype (ST8) in sprayed and unsprayed enclosures. Biopesticidal ST8 proliferated in hosts after spraying but was also found naturally associated with leaves more than any other genotype. In an independent experiment several ST8 isolates proved better than a range of non-pathogenic STs at endophytic and epiphytic colonization of seedlings from soil. This is the first experimental demonstration of Bt behaving as a specialized insect pathogen in the field. These data provide a basis for understanding both Bt ecology and the influence of anthropogenic factors on Bt populations. This natural population of Bt showed habitat associations and a population structure that differed markedly from previous MLST studies of less ecologically coherent B. cereus sample collections. The host-specific adaptations of ST8, its close association with its toxin plasmid and its high prevalence within its clade are analogous to the biology of Bacillus anthracis. This prevalence also suggests that selection for resistance to the insecticidal toxins of ST8 will have been stronger than for other toxin classes.

Vyšlo v časopise: Environmental Factors Determining the Epidemiology and Population Genetic Structure of the Group in the Field. PLoS Pathog 6(5): e32767. doi:10.1371/journal.ppat.1000905
Kategorie: Research Article
prolekare.web.journal.doi_sk: https://doi.org/10.1371/journal.ppat.1000905

Souhrn

Zdroje

1. JensenGB

HansenBM

EilenbergJ

MahillonJ

2003 The hidden lifestyles of Bacillus cereus and relatives. Environmental Microbiology 5 631 640

2. SchnepfE

CrickmoreN

Van RieJ

LereclusD

BaumJ

1998 Bacillus thuringiensis and its pesticidal crystal proteins. Microbiology and Molecular Biology Reviews 62 775 806

3. ISAAA 2008 Global status of commercialized Biotech/GM crops: 2008. International Service for the Aquisition of Agri-biotech Applications Briefs 37-2007: http://www.isaaa.org/

4. GlareTR

O'CallaghanM

2000 Bacillus thuringiensis: biology, ecology and safety. Chicester John Wiley

5. RaymondB

ElliotSL

EllisRJ

2008 Quantifying the reproduction of Bacillus thuringiensis HD-1 in cadavers and live larvae of Plutella xylostella. Journal of Invertebrate Pathology 98 307 313

6. PrasertphonS

AreekulP

TanadaY

1973 Sporulation of Bacillus thuringiensis in cadavers. Journal of Invertebrate Pathology 21 205 207

7. SuzukiMT

LereclusD

ArantesOMN

2004 Fate of Bacillus thuringiensis strains in different insect larvae. Canadian Journal of Microbiology 50 973 975

8. PorcarM

CaballeroP

2000 Molecular and insecticidal characterization of a Bacillus thuringiensis strain isolated during a natural epizootic. Journal of Applied Microbiology 89 309 316

9. TakatsukaJ

KunimiY

1998 Replication of Bacillus thuringiensis in larvae of the Mediterranean flour moth, Ephestia kuehniella (Lepidoptera: Pyralidae): Growth, sporulation and insecticidal activity of parasporal crystals. Applied Entomology and Zoology 33 479 486

10. KnellRJ

BegonM

ThompsonDJ

1998 Host-pathogen population dynamics, basic reproductive rates and threshold densities. Oikos 81 299 308

11. DeluccaAJ

SimonsonJG

LarsonAD

1981 Bacillus thuringiensis distribution in soils of the United States. Canadian Journal of Microbiology 27 865 870

12. HendriksenNB

HansenBM

JohansenJE

2006 Occurrence and pathogenic potential of Bacillus cereus group bacteria in a sandy loam. Antonie Van Leeuwenhoek International Journal of General and Molecular Microbiology 89 239 249

13. KaurS

SinghA

2000 Natural occurrence of Bacillus thuringiensis in leguminous phylloplanes in the New Delhi region of India. World Journal of Microbiology & Biotechnology 16 679 682

14. MartinPAW

TraversRS

1989 Worldwide abundance and distribution of Bacillus thuringiensis isolates. Applied and Environmental Microbiology 55 2437 2442

15. SmithRA

CoucheGA

1991 The phylloplane as a source of Bacillus thuringiensis variants. Applied and Environmental Microbiology 57 311 315

16. ElliotSL

SabelisMW

JanssenA

van der GeestLPS

BeerlingEAM

2000 Can plants use entomopathogens as bodyguards? Ecology Letters 3 228 235

17. TabashnikBE

GassmannAJ

CrowderDW

CarriereY

2008 Insect resistance to Bt crops: evidence versus theory. Nature Biotechnology 26 199 202

18. Vilas-BoasG

SanchisV

LereclusD

LemosMVF

BourguetD

2002 Genetic differentiation between sympatric populations of Bacillus cereus and Bacillus thuringiensis. Applied and Environmental Microbiology 68 1414 1424

19. EnrightMC

SprattBG

1998 A multilocus sequence typing scheme for Streptococcus pneumoniae: identification of clones associated with serious invasive disease. Microbiology (UK) 144 3049 3060

20. MaidenMCJ

BygravesJA

FeilE

MorelliG

RussellJE

1998 Multilocus sequence typing: A portable approach to the identification of clones within populations of pathogenic microorganisms. Proceedings of the National Academy of Sciences of the United States of America 95 3140 3145

21. CardazzoB

NegrisoloE

CarraroL

AlberghiniL

PatarnelloT

2008 Multiple-locus sequence typing and analysis of toxin genes in Bacillus cereus food-borne isolates. Applied and Environmental Microbiology 74 850 860

22. DidelotX

BarkerM

FalushD

PriestFG

2009 Evolution of pathogenicity in the Bacillus cereus group. Systematic and Applied Microbiology 32 81 90

23. DidelotX

FalushD

2007 Inference of bacterial microevolution using multilocus sequence data. Genetics 175 1251 1266

24. PriestFG

BarkerM

BaillieLWJ

HolmesEC

MaidenMCJ

2004 Population structure and evolution of the Bacillus cereus group. Journal of Bacteriology 186 7959 7970

25. HoffmasterAR

NovakRT

MarstonCK

GeeJE

HelselL

2008 Genetic diversity of clinical isolates of Bacillus cereus using multilocus sequence typing. BMC Microbiology 8 191

26. CollierFA

ElliotSL

EllisRJ

2005 Spatial variation in Bacillus thuringiensis/cereus populations within the phyllosphere of broad-leaved dock (Rumex obtusifolius) and surrounding habitats. FEMS Microbiology Ecology 54 417 425

27. SorokinA

CandelonB

GuillouxK

GalleronN

Wackerow-KouzovaN

2006 Multiple-locus sequence typing analysis of Bacillus cereus and Bacillus thuringiensis reveals separate clustering and a distinct population structure of psychrotrophic strains. Applied and Environmental Microbiology 72 1569 1578

28. KinkelLL

1997 Microbial population dynamics on leaves. Annual Review of Phytopathology 35 327 347

29. NicholsonWL

2002 Roles of Bacillus endospores in the environment. Cellular and Molecular Life Sciences 59 410 416

30. BizzarriM

BishopA

2008 The ecology of Bacillus thuringiensis on the phylloplane: colonization from soil, plasmid transfer, and interaction with larvae of Pieris brassicae. Microbial Ecology 56 133 139

31. SilimelaM

KorstenL

2007 Evaluation of pre-harvest Bacillus licheniformis sprays to control mango fruit diseases. Crop Protection 26 1474 1481

32. HalversonLJ

ClaytonMK

HandelsmanJ

1993 Population biology of Bacillus cereus UW85 in the rhizosphere of field-grown soy beans. Soil Biology and Biochemistry 25 485 493

33. HendriksenNB

HansenBM

2002 Long-term survival and germination of Bacillus thuringiensis var. kurstaki in a field trial. Canadian Journal of Microbiology 48 256 261

34. SaileE

KoehlerTM

2006 Bacillus anthracis multiplication, persistence, and genetic exchange in the rhizosphere of grass plants. Applied and Environmental Microbiology 72 3168 3174

35. DragonDC

RennieRP

1995 The ecology of anthrax spores: tough but not invincible. Canadian Vetinary Journal 36 295 301

36. MaduellP

ArmengolG

LlagosteraM

2008 B. thuringiensis is a poor colonist of leaf surfaces. Microbial Ecology 55 212 219

37. SayyedAH

RaymondB

Ibiza-PalaciosMS

EscricheB

WrightDJ

2004 Genetic and biochemical characterization of field-evolved resistance to Bacillus thuringiensis toxin Cry1Ac in the diamondback moth, Plutella xylostella. Applied and Environmental Microbiology 70 7010 7017

38. IqbalM

VerkerkRHJ

FurlongMJ

OngP-C

SyedRA

1996 Evidence for resistance to Bacillus thuringiensis (Bt) subsp. kurstaki HD-1, Bt subsp. aizawai and abamectin in field populations of Plutella xylostella from Malaysia. Pesticide Science 48 89 97

39. TabashnikBE

LiuYB

MalvarT

HeckelDG

MassonL

1997 Global variation in the genetic and biochemical basis of diamondback moth resistance to Bacillus thuringiensis. Proceedings of the National Academy of Sciences of the United States of America 94 12780 12785

40. TabashnikB

CarrièreY

2009 Insect resistance to genetically modified crops.

FerryN

GatehouseAMR

Environmental impact of genetically modified crops Wallingford CABI 74 100

41. BizzarriM

PrabhakarA

BishopA

2008 Multiple-locus sequence typing analysis of Bacillus thuringiensis recovered from the phylloplane of clover (Trifolium hybridum) in vegetative form. Microbial Ecology 55 619 625

42. BizzarriMF

BishopAH

2007 Recovery of Bacillus thuringiensis in vegetative form from the phylloplane of clover (Trifolium hybridum) during a growing season. Journal of Invertebrate Pathology 94 38 47

43. GouldF

AndersonA

JonesA

SumerfordD

HeckelDG

1997 Initial frequency of alleles for resistance to Bacillus thuringiensis toxins in field populations of Heliothis virescens. Proceedings of the National Academy of Science of the USA 94 3519 3523

44. TabashnikBE

PatinAL

DennehyTJ

LiuY-B

CarrièreY

2000 Frequency of resistance to Bacillus thuringiensis in field populations of pink bollworm. Proceedings of the National Academy of Sciences USA 97 12980 12984

45. GonzalezJM

CarltonBC

1980 Patterns of plasmid DNA in crystalliferous and acrystalliferous strains of Bacillus thuringiensis. Plasmid 3 92 98

46. HotonFM

AndrupL

SwiecickaI

MahillonJ

2005 The cereulide genetic determinants of emetic Bacillus cereus are plasmid-borne. Microbiology-Sgm 151 2121 2124

47. OkinakaRT

CloudK

HamptonO

HoffmasterAR

HillKK

1999 Sequence and organization of pXO1, the large Bacillus anthracis plasmid harboring the anthrax toxin genes. Journal of Bacteriology 181 6509 6515

48. Vilas-BoasG

Vilas-BoasLA

LereclusD

ArantesOMN

1998 Bacillus thuringiensis conjugation under environmental conditions. FEMS Microbiology Ecology 25 369 374

49. HanCS

XieG

ChallacombeJF

AltherrMR

BhotikaSS

2006 Pathogenomic sequence analysis of Bacillus cereus and Bacillus thuringiensis isolates closely related to Bacillus anthracis. Journal of Bacteriology 188 3382 3390

50. PriestFG

GoodfellowM

ToddC

1988 A numerical classification of the genus Bacillus. J Gen Microbiol 134 1847 1882

51. KimK

SeoJ

WheelerK

ParkC

KimD

2005 Rapid genotypic detection of Bacillus anthracis and the Bacillus cereus group by multiplex real-time PCR melting curve analysis. FEMS Immunology and Medical Microbiology 43 301 310

52. DamgaardPH

GranumPE

BrescianiJ

TorregrossaMV

EilenbergJ

1997 Characterization of Bacillus thuringiensis isolated from infections in burn wounds. FEMS Immunology and Medical Microbiology 18 47 53

53. HernandezE

RamisseF

DucoureauJ

1998 Bacillus thuringiensis subsp. konkukian (serotype H34) superinfection: case report and experimental evidence of pathogenicity in immunosuppressed mice Journal of Clinical Microbiology

54. JacksonSG

GoodbrandRB

AhmedR

KasatiyaS

1995 Bacillus cereus and Bacillus thuringiensis isolated in a gastroenteritis outbreak investigation. Letters in Applied Microbiology 21 103 105

55. YaraK

KunimiY

IwahanaH

1997 Comparative studies of growth characteristic and competitive ability in Bacillus thuringiensis and Bacillus cereus in soil. Applied Entomology and Zoology 32 625 634

56. SmithJ

SmithN

O'RourkeM

SprattB

1993 How clonal are bacteria? Proceedings of the National Academy of Sciences

57. TourasseNJ

HelgasonE

ØkstadOA

HegnaIK

KolstøA-B

2006 The Bacillus cereus group: novel aspects of population structure and genome dynamics. Journal of Applied Microbiology 101 579 593

58. VassilevaM

ToriiK

OshimotoM

OkamotoA

AgataN

2007 A new phylogenetic cluster of cereulide-producing Bacillus cereus strains. Journal of Clinical Microbiology 45 1274 1277

59. HoffmasterAR

RavelJ

RaskoDA

ChapmanGD

ChuteMD

2004 Identification of anthrax toxin genes in a Bacillus cereus associated with an illness resembling inhalation anthrax. Proceedings of the National Academy of Sciences of the United States of America 101 8449 8454

60. AusubelFM

BrentR

R.E.K

MooreDD

SeidmanJG

1999 Short protocols in molecular biology. New York John Wiley

61. RaymondB

JohnstonPR

WrightDJ

EllisRJ

CrickmoreN

2009 A mid-gut microbiota is not required for the pathogenicity of Bacillus thuringiensis to diamondback moth larvae. Environmental Microbiology 11 2556 2563

62. SabaratnamS

BeattieG

2003 Differences between Pseudomonas syringae pv. syringae B728a and Pantoea agglomerans BRT98 in epiphytic and endophytic colonization of leaves. Applied and Environmental Microbiology 69 1220 1228

63. JolleyKA

ChanMS

MaidenMC

2004 mlstdbNet - distributed multi-locus sequence typing (MLST) databases. BMC Bioinformatics 5 86

64. BrooksSP

GelmanA

1998 General methods for monitoring convergence of iterative simulations. Journal of Computational and Graphical Statistics 7 434 455

65. GelmanA

RubinDB

1992 Inference from iterative simulation using mulitple sequences. Statistical science 7 457 472

66. PritchardJK

StephensM