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Title: MOLECULAR ANALYSIS OF SOIL MICROBIAL COMMUNITIES ASSOCIATED WITH BT AND NON-BT CORN

Author
item Blackwood, Christopher
item DIVELY, GALEN - UNIV MARYLAND
item Buyer, Jeffrey

Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 7/23/2003
Publication Date: 10/1/2003
Citation: Blackwood, C.B., Dively, G., Buyer, J.S. 2003. Molecular analysis of soil microbial communities associated with bt and non-bt corn [abstract]. Agronomy Abstracts. S03-Blackwood 955464-Oral.

Interpretive Summary: None needed

Technical Abstract: Bt corn is a transgenic crop expressing toxins which are targeted to specific insect pests. In one year, growth of Bt corn causes an approximate 1000-fold increase in the amount of Cry protein present in the soil. In this study, we tested the hypothesis that growth of Bt corn causes a change in soil and rhizosphere microbial communities relative to the communities associated with other agronomic practices. This hypothesis was tested by sampling soil and rhizosphere from three field experiments in different locations. Two experiments (in place 4 years) were 2 x 2 complete factorial designs, with one factor being the presence of either Bt corn targeting European corn-borer or an isogenic non-Bt line, and the other experimental factor being the use of conventional insecticides. The third experiment (in place 1 year) involved Bt corn targeting corn rootworm, and only tested the effects of conventional insecticide spraying within the non-Bt corn treatment. Microbial communities were fingerprinted by PLFA profiles and a modified T-RFLP method (paramagnetic bead-enabled T-RFLP). Various groups of bacteria and fungi were targeted in individual T-RFLP analyses by use of novel phylum-specific PCR primers. The primers were previously tested by sequencing from soil-derived clone libraries.