NatureNews published online; opinion posted on 2010-09-04. Can be accessed at http://www.nature.com/news/2010/100806/full/news.2010.393.html .
The Sagers report1 on the establishment of feral communities of two GM herbicide resistant canola varieties (Monsanto's Roundup Ready glyphosate tolerant canola and Bayer Crop Science's Liberty herbicide gluphosinate resistant canola) in the USA is a confirmation of earlier reports from Japan2, Australia and China. Feral communities of cropped plants originating from agrosystems are so common a phenomenon that it does not evoke attention. This is especially so because agrotechnique-pampered domesticated plant species unlike invasive weeds fail to establish communities in highly competitive natural ecosystems.
GM canola has mimicked an invasive weed in its establishment as feral communities and creation of double herbicide resistant hybrids apparently through cross pollination. This is a matter of serious concern. The report also indicates that transgenes do indeed cross genomic barriers albeit intervarietal barriers in the presnt case.
Doubts are rightly raised about the adequacy of GM regulatory procedures that evade provisions for monitoring the flow of transgenes or their parts to non-target genomes. A major flaw in GM biosafety monitoring mechanism is that assessments, if properly carried out, would take several years in most cases. Unfortunately, protocols for the emigration of transgenic plants via the contrivances of wind, flash floods, insects, birds and terrestrial animals are neither adequate nor transparent. GM biosafety mechanisms should include both the flight of transgenics to non-target ecosystems and the flow of transgenes to non-target genomes in a manner to be cost effective and universally reproducible on quick time basis.
Most regulatory mechanisms avoid the monitoring of subsoil residues of GM crops and their effects on rhizosphere biota and genomes of soil microorganism and on extracellular DNA. These aspects should be made essential components of GM biosafety assessment practice. Experimental formats for real time flow of transgenes are suggested here.
Subsoil metagenomic analysis is quick and common place for a moderately equipped laboratory 3, 4, 5 Transfer of large DNA by horizontal transfers across genomic barriers is well known. It would be easy for GM biosafety assessors to monitor relocation of transgenes or their parts to non-target DNA of the metagenome. Simple PCR runs of metagenomic DNA will reveal the presence or absence of the transgene under consideration. Presence of transgene DNA would ensure that transgene migration has indeed occurred.
Extracellular DNA (eDNA) is known to persist in soil environment for long 6, 7, 8. In all likelihood dead roots, mycorrhyzae, leaf litters, left over stubbs etc. will add to soil eDNA pools including the transgene or its part. Persisting eDNA containing the transgene or their parts may be recoursed to HGT to laterally move to other genomes at a later time. Tracing the presence of transgenes or parts thereof on eDNA would caution biosafety assessors about later possibilities of transgene flights from GM crop plants.
These new areas of researches should be publicly funded projects and must not be left to the will and wisdom of GM crop developers and lobbyists.
References
1. Natasha Gilbert 2010 GM crop escapes into the American wild: Transgenic canola found growing freely in North Dakota, Nature News, Published online 6 August 2010, Nature, doi:10.1038/news.2010.393.
2. Japan for Sustainability 2009 Japanese Consumer's Union Finds GM Canola Growing in Chiba Prefectur; International Society for Agricultural Meteorology December 23, 2009 09:47: http://www.agrometeorology.org/news/whats-new/japanese-consumers-union-finds-gm-canola-growing-in-chiba-prefectur; accessed on 4 September 2010.
3. Abulencia, C. B., Wyborski, D. L., Garcia, J. A., Podar, M., Chen, W., Chang, S. H. et al. (2006). Environmental whole-genome amplification to access microbial populations in contaminated sediments. Applied and Environmental Microbiology 725, 3291-3301.
4. Pushpender K. Sharma, Neena Capalash and Jagdeep Kaur 2007 An improved method for single step purification of metagenomic DNA; Molecular Biotechnology Volume 36, Number 1, 61-63.
5. Mei-Fong Pang, Noorlidah Abdullah, Choon-Weng Lee and Ching-Ching Ng 2008 Isolation of High Molecular Weight DNA from Forest Topsoil for Metagenomic Analysis; Asia Pacific Journal of Molecular Biology and Biotechnology, Vol. 16 (2): 35-41.
6. Nielsen KM, Johnsen PJ, Bensasson D, Daffonchio D. 2007 Release and persistence of extracellular DNA in the environment; Environ Biosafety Res., 6:37-53.
7. Mitsuhiro Itaya and Shinya Kaneko 2010 Integration of stable extracellular DNA released from Escherichia coli into the Bacillus subtilis genome vector by culture mix method; Nucleic Acids Research 2010 38(8):2551-2557
8. Paul JH, Jeffrey WH, DeFlaun MF: Production of extracellular nucleic acids by genetically altered bacteria in aquatic-environment microcosms. Appl Environ Microbiol 1987, 55:1865-1869.
S.K.T. Nasar Ph. D. (IIT, Kharagpur)
Professor
Department of Biotechnology
Bengal College of Engineering and Technology
(Affiliated to West Bengal University of Technology)
Durgapur, West Bengal
Former Director of Research
Bidhan Chandra Krishi Viswavidyalaya
(i.e. Bidhan Chandra Agricultural University)
&
Honorary Vice-President
Maromi Human Resource Development Society (NGO)
Kolkata, West Bengal
skt.nasar@gmail.com
