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[SANET-MG] dangerous field test releases of pathogenic bacterium
Dangerous Field Test of Non-pathogenic GM Bacteria
The non-pathogenic GM bacteria not only carry antibiotic resistance
marker genes, but the proposed field tests will also involve the release
of the wild-type bacterium that is pathogenic to rice and may cause
disease in human beings
Prof. Joe Cummins and Dr. Mae-Wan Ho
This report has been submitted to the USDA on behalf of ISIS, please
Bacterium causing rice panicle blight
The United States Department of Agriculture Animal and Plant Health
Inspection Service (USDA/APHIS) carried out an Environmental Assessment
 in response to a permit application (06-111-01r) received from Dr.
Milton Rush of Louisiana State University for a field test of two
non-pathogenic, genetically engineered strains of Burkholderia glumae,
and is available for public comment by 19 July 2007 at:
Burkholderia glumae Kurita et Tabei is a bacterial plant pathogen that
causes bacterial panicle blight in rice, and is transmitted by infected
seed. This bacterium was first described in Japan as the cause of grain
rotting and seedling blight and is considered one of the most important
rice pathogens in Japan. Epidemics of panicle blight occurred in the
southern rice producing area of the United States during the 1995 and
1998 growing seasons, with yield losses in some fields estimated to be
as high as 40 percent. Currently, there is no control method for panicle
blight in the US, where most commercially grown rice varieties are
susceptible to the disease. Field-testing non-pathogenic, transgenic
strains of B. glumae is supposed to provide information on bacterial
panicle blight infection of rice, and indicate potential routes for
control of the pathogen.
Non-pathogenic transgenic bacteria contain two antibiotic resistance
B. glumae has been modified by disrupting the disease-causing gene,
resulting in avirulent or non-pathogenic transgenic strains.
One virulence factor in B. glumae is the compound toxoflavin , a
yellowish substance that results in significant damage to rice in the
infected plants. Toxoflavin is produced in Burkholderia by an operon
(group of genes with a defined function) consisting of the tox gene
cluster (toxABCDE) controlled by the toxR gene that is activated when
the bacterium invades the rice plant. Disruption of the toxA gene
(methyltransferase) results in mutants that do not produce toxoflavin.
The cloning vector also contains two selectable markers, the gene
(nptII) for neomycin phosphotransferase from Streptomyces kanamyceticus
and the gene (bla) for beta-lactamase from Escherichia coli, providing
resistance to kanamycin and ampicillin, respectively. The promoter for
each of the genes is the Bacteriophage T7 promoter, and the terminator a
synthetic TAA codon sequence. The donor DNA sequences are stably and
irreversibly integrated into the bacterial genome, where they are
maintained and inherited as any other genes of the bacteria cell .
The avirulent non-pathogenic strain therefore also carries stable
resistance to the antibiotics kanamycin and ampicllin. The potential for
horizontal gene transfer of the antibiotic resistance markers to soil
bacteria is acknowledged in the USDA/APHIS assessment, but is presumed
to have insignificant consequences. This presumption is not borne out by
a wealth of evidence we have presented repeatedly to our regulators, the
most recent in June 2007  (GM Food Nightmare Unfolding in the
Regulatory Sham , ISIS scientific publication)
Pathogenic wild-type bacteria will be released in field-tests of
Two experiments will be conducted; the first evaluates toxoflavin as a
disease causing agent by challenging the rice plants with wild-type B.
glumae, the second involves inoculating the rice with the transgenic
avirulent bacterium followed by challenge with the virulent strain to
see whether or not the presence of the avirulent strain will protect
rice from B. glumae infection. These are obviously dangerous experiments
to be carried out in the open fields; as the wild-type pathogen could
easily spread from the experimental fields to other rice crops. The
risks are unjustifiable, especially when there are other safer strategies.
An alternative approach to controlling B. glumae is via ‘quorum
sensing’, a regulatory network influencing virulence based on the local
density of bacteria that intercommunicate with one another. Quorum
sensing can occur within a single bacterial species as well as between
disparate species, and can regulate a host of different processes,
essentially serving as a simple communication network. The bacteria
signal to one another via special molecules. For example, toxoflavin is
regulated by a quorum sensing mechanism that uses N-acyl homoserine
lactones as signal molecules. A Burkholderia endophyte (a bacterium that
lives inside the plant) was selected from rice and found to be
non-pathogenic to rice and to inhibit pathogenic fungi. The endophyte,
modified with a gene from Bacillus thuringiensis specifying N-acyl
homoserine lactones, was found to prevent toxoflavin synthesis and
virulence of B. glumae . Genetic modification involving quorum
sensing provides an alternative, also avoids use of the antibiotic
résistance genes described above because toxoflavin can be detected by
its fluorescence and its absence is readily detected.
Another danger from the transgenic B. glumae proposed for release is
that the genus contains serious pathogens for humans: B. cepacia is a
potent pathogen  (Bio-remediation Without Caution, SiS 230; B.
thailandensis caused pneumonia and septicemia ; B. dolosa is
pathogenic for people with cystic fibrosis ; B. gladioli caused
ocular keratitis in an individual with diabetes, and is also found in
other diseases ; and a number of other Burkholderia species are
associated with human infections. It is not at all surprising,
therefore, that a B. glumae infection was observed in an infant with
chronic granulomatous disease . Further investigation of the
clinically isolated strain of B. glumae showed that the bacterium caused
severe disease symptoms in rice, and a quorum sensing regulated secreted
lipase was implicated in the pathogenesis of the clinical strain .
The USDA/APHIS assessment did not consider human infection by B. glumae
a serious matter  based on the single human case, nor did it
recommend precaution for those working with the pathogen, who will most
likely take the pathogen to their homes, families and neighbours. The
dangers of the transgenic B. glumae itself as a potential pathogen armed
with two antibiotic resistance marker genes that could further transfer
horizontally to other known Burkholderia pathogens appear to have
completely escaped the notice of USDA/APHIS. Both USDA/APHIS and the
scientists involved should be held responsible for any harm caused to
people and crops, should they allow this field release to go ahead.
1. U.S. Department of Agriculture Animal and Plant Health Inspection
Service Biotechnology Regulatory Services USDA APHIS Environmental
Assessment In response to a permit application (06-111-01r) received
from Dr. Milton Rush of Louisiana State University for a field test of
two non-pathogenic, genetically engineered strains of Burkholderia
2. Ho MW, Cummins J and Saunders P. GM food nightmare unfolding in the
regulatory sham. Microbial Ecology in Health and Disease 2007,19, 2, 66
3. Cho HS, Park SY, Ryu CM, Kim JF, Kim JG and Park SH. Interference of
quorum sensing and virulence of the rice pathogen Burkholderia glumae by
an engineered endophytic bacterium FEMS Microbiol Ecol. 2007
4. Cummins J and Ho MW. Bio-remediation without caution Science in
Society 23, 40, 2004
5. Glass MB, Gee JE, Steigerwalt AG, Cavuoti D, Barton T, Hardy RD,
Godoy D, Spratt BG, Clark TA and Wilkins PP. Pneumonia and septicemia
caused by Burkholderia thailandensis in the United States. J Clin
Microbiol. 2006, 44(12),:4601-4.
6. Caraher E, Duff C, Mullen T, Mc Keon S, Murphy P, Callaghan M and
Invasion and biofilm formation of Burkholderia dolosa is comparable with
Burkholderia cenocepacia and Burkholderia multivorans. J Cyst Fibros.
7. Ritterband D, Shah M, Cohen K, Lawrence J and Seedor J. Burkholderia
gladioli keratitis associated with consecutive recurrent
endophthalmitis. Cornea 2002, 21(6), 602-3.
8. Weinberg JB, Alexander BD, Majure JM, Williams LW, Kim JY, Vandamme P
and LiPuma JJ. Burkholderia glumae infection in an infant with chronic
granulomatous disease. J Clin Microbiol. 2007, 45(2), 662-5.
9. Devescovi G, Bigirimana J, Degrassi G, Cabrio L, Lipuma JJ, Kim J,
Hwang I and Venturi V. A clinical isolate of Burkholderia glumae causes
severe disease symptoms in rice; involvement of a quorum sensing
regulated secreted lipase. Appl Environ Microbiol 2007 Jun 8; [Epub
ahead of print] doi:10.1128/AEM.00105-07
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