Effects of the cultivation of genetically modified Bt crops on nontarget soil organisms - Microbial Ecology in Sustainable Agroecosystems - page 163

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

Protease, neutral
phosphatase, cellulase,
and dehydrogenase
activities;
methanogenesis,
hydrogen production,
and anaerobic
respiration

Enzyme activity
assays

Laboratory Flooded soils amended

with Bt (KMD) and
non- Bt (Xiushui 11)
rice straw

Cry1Ab Some differences in

protease, neutral
phosphatase, and
cellulase activities
detected at the early
incubation stage but did
not persist
Differences in dehydroge-
nase activity, methano-
genesis, hydrogen
production, and
anaerobic respiration
between soil amended
with Bt or non- Bt rice
straw persisted through-
out the experiment

Wu et al.
(2004a)

Rhizospheric and
heterotrophic bacteria

Denaturing
gradient gel
electrophoresis
(DGGE)
Respiration rates
Culturing
technique

Microcosm
Greenhouse

Soil with Bt ( Bt 11 and
Bt 176) and non- Bt
maize
Soil amended with Bt
or non- Bt maize
residue

Cry1Ab Differences in

rhizospheric eubacterial
communities (both total
and active) and in
culturable rhizospheric
heterotrophic bacteria
in soil cultivated with
Bt versus non- Bt maize
Lower soil respiration in
soils amended with Bt
maize residue;
differences in soil
bacteria isolated from
soil amended with Bt
versus non- Bt maize

Castaldini et
al. (2005)

(continued)