HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Figures Only Full Text Free Full Text (PDF) Free Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (3) Citing Articles via Google Scholar Google Scholar Articles by Naef, A. Articles by Défago, G. Search for Related Content PubMed PubMed Citation Articles by Naef, A. Articles by Défago, G. Agricola Articles by Naef, A. Articles by Défago, G. Related Collections Soil Microbiology Maize Ecological Risk Assessment

TECHNICAL REPORTS

Ecological Risk Assessment

Impact of Transgenic Bt Maize Residues on the Mycotoxigenic Plant Pathogen Fusarium graminearum and the Biocontrol Agent Trichoderma atroviride

^a Plant Pathology, Institute of Integrative Biology, ETH Zurich, 8092 Zurich, Switzerland
^b SMart Nose SA, 2074 Marin-Epagnier, Switzerland

^* Corresponding author (genevieve.defago{at}agrl.ethz.ch)

Received for publication September 2, 2005. Transformation of maize with genes encoding for insecticidal crystal (Cry) proteins from Bacillus thuringiensis (Bt) could have an impact on the saprophytic survival of plant pathogens and their antagonists on crop residues. We assessed potential effects on the mycotoxin deoxynivalenol (DON)-producing wheat and maize pathogen Fusarium graminearum and on the biocontrol agent Trichoderma atroviride. Purified Cry1Ab protein caused no growth inhibition of these fungi on agar plates. Cry1Ab concentrations above levels common in Bt maize tissue stimulated the growth of F. graminearum. The fungi were also grown on -radiation-sterilized leaf tissue of four Bt maize hybrids and their non transgenic isolines collected at maize maturity on a field trial in 2002 and 2003. Both fungi degraded the Cry1Ab protein in Bt maize tissue. Fungal biomass quantification with microsatellite-based polymerase chain reaction (PCR) assays revealed differential fungal growth on leaf tissue of different maize varieties but no consistent difference between corresponding Bt and non-Bt hybrids. Generally, year of maize tissue collection had a greater impact on biomass production than cultivar or Bt transformation. The mycotoxin DON levels observed in maize tissue experiments corresponded with patterns in F. graminearum biomass, indicating that Bt transformation has no impact on DON production. In addition to bioassays, maize leaf tissue was analyzed with a mass spectrometer–based electronic nose, generating fingerprints of volatile organic compounds. Chemical fingerprints of corresponding Bt and non-Bt leaf tissues differed only for those hybrid pairs that caused differential fungal biomass production in the bioassays. Our results suggest that Cry1Ab protein in maize residues has no direct effect on F. graminearum and T. atroviride but some corresponding Bt/non-Bt maize hybrids differ more in composition than Cry protein content alone, which can affect the saprophytic growth of fungi on crop residues.

Abbreviations: Bt, Bacillus thuringiensis • DON, deoxynivalenol • ELISA, enzyme-linked immunosorbent assay • PCR, polymerase chain reaction • SNA, synthetic nutrient-poor agar

This article has been cited by other articles:

				I. Icoz, D. Saxena, D. A. Andow, C. Zwahlen, and G. Stotzky Microbial populations and enzyme activities in soil in situ under transgenic corn expressing cry proteins from Bacillus thuringiensis. J. Environ. Qual., March 1, 2008; 37(2): 647 - 662. [Abstract] [Full Text] [PDF]