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Biodegradation of genetically modified seeds and plant tissues
during composting
T. Reuter1, T. W. Alexander1,
W. Xu2,3, K. Stanford2 and
T. A. McAllister1*
Abstract
BACKGROUND: The increasing global market of genetically modified (GM)
crops amplifies the potential for unintentional contamination of
food and feed with GM plants. Methods proposed for disposal of crop
residues should be assessed to prevent unintended distribution of
GM materials. Composting of organic material is inexpensive and location-independent.
The objective of this study was to determine the effectiveness of
composting for disposal of GM plants in terms of reducing seed viability
and promoting the degradation of endogenous as well as transgenic
DNA.
RESULTS: Duplicate samples of corn kernels, alfalfa leaves, and GM
canola seeds, meal and pellets were sealed in porous nylon bags and
implanted in duplicate 85 000 kg (initial weight) feedlot manure compost
piles. Samples were collected at intervals over 230 days of composing.
Canola seeds and corn kernels were not viable after 14 days of composting
with temperatures in the piles exceeding 50 °C. In all samples,
PCR analyses revealed that plant endogenous and transgenic fragments
were substantially degraded after 230 days of composting. Southern
blotting of genomic DNA isolated from canola seeds identified differences
in the persistence of endogenous, transgenic, and bacterial DNA.
CONCLUSION: Composting GM and non-GM plant materials with manure rendered
seeds non-viable, and resulted in substantial, although not complete,
degradation of endogenous and transgenic plant DNA. This study demonstrates
that composting could be effective for disposing of GM crops in the
event of their inadvertent entry into the food or feed chain.
Source
Journal of the Science of Food and Agriculture (2010) 90: 650-657
Author Locations & Affiliations
(1) Agriculture and Agri-Food Canada, Lethbridge Research
Centre, P.O. Box 3000, Lethbridge, Alberta, T1J 4B1, Canada
(2) Alberta Agriculture and Rural Development, Agriculture Centre,
Lethbridge, Alberta, T1J 4V6, Canada
(3) Department of Bioscience and Biotechnology, Dalian University
of Technology, Dalian 116024, China
* Corresponding author, E-mail tim.mcallister@agr.gc.ca
en français
Posted February 2010