Autori: Elena Marcela Badea, Flori Chelu, Anca Lãcãtuşu

Editorial: ISSN: 1224-5984, Romanian Biotechnological Letters , 15 (1), p.55-62, 2010.

Rezumat:

Since the introduction of insect-resistant crops in 1996, cultivation of this group of genetically
modified crops has grown substantially. There are many Bt corn events in field trials, but only one is
commercialized on the Romanian market. The levels of the protein in plant tissue would be valuable in
determining the protein concentration to which nontarget organisms may be exposed. The soil fate of
the Bt protein is a key parameter governing exposure of nontarget organisms in this environment. The
objectives of our study were: (i) to investigate the impact of the soil type on Bt expression levels in
transgenic corn tissue (leaves, roots seed); (ii) to monitor the time-dependent degradation of the cry1Ab
protein in three soil types favorable for corn growing, with different physicochemical characteristics.
Detection and quantification of Cry1Ab protein in tissue (leaves, roots and seeds) and soil
extracts was conducted using ELISA method with a commercially available test system for detecting
Cry1Ab/Cry1Ac proteins (QuantiPlate Kit for Cry1Ab/Cry1Ac; Agdia), following the recommended
protocol of the manufacturer. To evaluate the potential of Bacillus thuringiensis (Bt) Cry1Ab protein
accumulation in soil, transgenic corn containing event MON 810 encoding the cry1Ab gene was grown
in greenhouse conditions in pots containing three types of soil. At the end of growing period, the corn
plants were incorporated into the soil. During vegetative period and at different time points after
biomass incorporation, soil samples were collected from pots, and the level of Cry1Ab protein in these
samples was determined using ELISA assay. Regarding Bt protein content, there is no difference
between plants grown in different soils types. The lowest Bt protein content was quantified in senescent
tissue and in seeds. The average chart for test soils shows an initial Bt protein increase after
incorporating the plant biomass into the greenhouse soil pots, with the Cry1Ab concentration peaking
at about 6 -9 weeks after incorporation, and declining slowly towards the 12-15 week (3-4 months)
sampling interval. Overall, our results supports the conclusion that the Cry1Ab protein does not
persist or accumulate in soil after incorporation in the soil of Bt corn plants expressing this protein.

Cuvinte cheie: Cry1Ab protein, Bt corn, MON 810; accumulation, soil

URL: http://www.rombio.eu/rbl1vol15Supplement/7%20Elena%20MArcela%20Badea.pdf