Selection of Specific Endophytic Bacterial Genotypes by Plants in Response to Soil Contamination

Steven D. Siciliano, Nathalie Fortin, Anca Mihoc, Gesine Wisse, Suzanne Labelle, Danielle Beaumier, Danielle Ouellette, Real Roy, Lyle G. Whyte, M. Kathy Banks, Paul Schwab, Ken Lee, Charles W. Greer

Research output: Contribution to journalArticlepeer-review

326 Scopus citations


Plant-bacterial combinations can increase contaminant degradation in the rhizosphere, but the role played by indigenous root-associated bacteria during plant growth in contaminated soils is unclear. The purpose of this study was to determine if plants had the ability to selectively enhance the prevalence of endophytes containing pollutant catabolic genes in unrelated environments contaminated with different pollutants. At petroleum hydrocarbon contaminated sites, two genes encoding hydrocarbon degradation, alkane monooxygenase (alkB) and naphthalene dioxygenase (ndoB), were two and four times more prevalent in bacteria extracted from the root interior (endophytic) than from the bulk soil and sediment, respectively. In field sites contaminated with nitroaromatics, two genes encoding nitrotoluene degradation, 2-nitrotoluene reductase (ntdAa) and nitrotoluene monooxygenase (ntnM), were 7 to 14 times more prevalent in endophytic bacteria. The addition of petroleum to sediment doubled the prevalence of ndoB-positive endophytes in Scirpus pungens, indicating that the numbers of endophytes containing catabolic genotypes were dependent on the presence and concentration of contaminants. Similarly, the numbers of alkB- or ndoB-positive endophytes in Festuca arundinacea were correlated with the concentration of creosote in the soil but not with the numbers of alkB- or ndoB-positive bacteria in the bulk soil. Our results indicate that the enrichment of catabolic genotypes in the root interior is both plant and contaminant dependent.

Original languageEnglish (US)
Pages (from-to)2469-2475
Number of pages7
JournalApplied and Environmental Microbiology
Issue number6
StatePublished - Jun 2001

ASJC Scopus subject areas

  • Biotechnology
  • Food Science
  • Applied Microbiology and Biotechnology
  • Ecology


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