EFFECT OF BT CORN ON SOIL MICROBIAL COMMUNITY PROFILES

Authors: Blackwood, Christopher; OAKES, ADAM - UNIVERSTITY OF MARYLAND; Buyer, Jeffrey

Submitted to: Ecological Society of America Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 9/1/2003
Publication Date: 10/8/2003
Citation: BLACKWOOD, C.B., OAKES, A., BUYER, J.S. EFFECT OF BT CORN ON SOIL MICROBIAL COMMUNITY PROFILES. ECOLOGICAL SOCIETY OF AMERICA 88TH ANNUAL MEETING SUPPLEMENT. 2003. P. 16.

Interpretive Summary:

Technical Abstract: Non-target effects of Bt-corn on soil microbial communities were assessed in a growth chamber experiment. The experiment tested the effects of two corn lines expressing different Cry endotoxins, in relation to their non-Bt parent lines. The corn was grown in three soil types of differing textures. Microbial community composition was assayed by methods which fingerprint communities through phospholipid fatty acids (PLFA), nucleotide sequence of the ribosomal small subunit, and community-level physiological (CLP) profiles. The ribosomal fingerprints were obtained using paramagnetic bead-enabled terminal restriction fragment length polymorphism (T-RFLP), targeting different microbial phyla separately with different PCR primers. No effects of Bt corn were found on Alpha or Beta Proteobacteria, low-GC aerobic Gram positives, Actinobacteria, or Planctomycetes using this procedure. There were also no significant effects of Bt corn on PLFA profiles. The eukaryotic PLFA biomarker was reduced in Bt corn treatments, although more specific fungal, mycorrhizal, or protozoan biomarkers were not. There was a significant effect of Bt corn on CLP profiles within one high-clay soil, although this accounted for a very small portion of the overall variability in the profiles. Overall, we found very little effect of Bt corn on soil microbial communities due to root exudation of Cry endotoxin. Soil type had a significant effect on all assays.