Effects of the cultivation of genetically modified Bt crops on nontarget soil organisms - Microbial Ecology in Sustainable Agroecosystems - page 186

Table 8.5 Effects of the Cultivation of Bt Crops or Amendment with Bt Protein on Protozoa

Organism/activity
tested

Bt crop plant/
experimental variable

Methodology Study location Protein Effect on organism(s) Source

Protozoa (amoebae,
ciliates, and
flagellates)

Culturing Laboratory Soil amended with

purified protein versus
unamended soil

Cry1Ab
Cry1Ac

No difference in the
number of protozoa in soil
between Bt and non- Bt
treatments

Donegan et
al. (1995)

Protozoa Culturing Plant growth

room

Soil cultivated with Bt
and non- Bt maize
Soil amended with
biomass of Bt and
non- Bt maize

Cry1Ab No significant difference in

protozoa numbers in soils
cultivated with or
amended with Bt or
non- Bt maize

Saxena and
Stotzky
(2001a)

Protozoa populations PLFA

CLPP

Field Soil cultivated with Bt

(MEB307 Bt ) and
non- Bt maize
(Monumental)

Cry1Ab Reduced protozoan

population under Bt maize
compared to non- Bt maize
at two sampling times

Griffiths et
al. (2005)

Protozoa numbers
(active and encysted)
Protozoa community
profile

MPN
CLPP

Greenhouse Soil cultivated with Bt

(MEB307 Bt ) and
non- Bt maize
(Monumental)
collected from field
sites

Cry1Ab Bt trait resulted in more

protozoa (amoebae)

Griffiths et
al. (2006)

Protozoa PLFA

CLPP

Field Soil cultivated with Bt

maize and non- Bt
maize

Cry1Ab Periodic increases in

protozoan abundance
under Bt -maize but effects
were not persistent

Griffiths,
Caul, et al.
(2007)

Protozoa MPN Field Soil cultivated with Bt

and non- Bt maize

Cry1Ab
Cry3Bb1

No significant differences
in the numbers of
protozoa between soils
cultivated with Bt and
non- Bt maize

Icoz et al.
(2008)

Source: Adapted and updated with permission from Icoz and Stotzky, 2008b.