Effects of the cultivation of genetically modified Bt crops on nontarget soil organisms - Microbial Ecology in Sustainable Agroecosystems - page 164

Table 8.3 Summary of Effects of Cultivation of Bt Crops or Amendment with Bt Proteins on Soil Bacteria (continued)
Organism/activity
tested

Bt crop plant/
experimental variable

Methodology Study location Protein Effect on bacteria Source

Bacterial community
structure

Single-strand
conformation
polymorphism
(SSCP)

Field Soil with Bt (Event

MON810) and non- Bt
maize

Cry1Ab Bacterial community

structure less affected
by Cry1Ab protein
than by other
environmental factors
(i.e., ontogeny of the
plants or
heterogeneities within
the field)

Baumgarte
and Tebbe
(2005)

Rhizosphere bacterial
diversity

Metabolic
profiling
(Biolog)
DGGE

Greenhouse
Field

Soil with Bt and non- Bt
maize

Cry1Ab Rhizosphere bacterial

diversity affected
more by soil texture
than by cultivation
with Bt maize

Fang et al.
(2005)

Bacteria PLFA

Culturing
technique

Field Soil with Bt and non- Bt

maize

Cry1Ab Lower ratio of gram-

positive to gram-
negative bacteria in
soil with Bt maize; no
difference in fungal/
bacterial ratio

Xue et al.
(2005)

Culturable bacteria,
enzyme activities

Culturing
technique

Microcosm Soil amended with Bt

and non- Bt maize
biomass

Cry1Ab No difference in

culturable bacteria or
enzyme activities

Flores et al.
(2005)

(continued)