fwds from nlpwessex - apologies for any cross posting:
1. GM cotton has reduced pest resistance
2. fungi buildup in glyphosate-treated soybean fields
3. GM Potatoes Alter Soil Ecology
4. GM cotton pest resistance in China and data from elsewhere
1. GM cotton has reduced pest resistance
The Journal of Cotton Science 4:232-236 (2000)
Plant Pathology and Nematology
Root-Knot Nematode Reproduction and Root Galling Severity on Related Conventional and Transgenic Cotton Cultivars
Patrick D. Colyer,* Terrence L. Kirkpatrick, W. David Caldwell, and Philip R. Vernon
ABSTRACT The root-knot nematode (Meloidogyne incognita Kofoid & White), a widespread and serious pest of cotton (Gossypium hirsutum L.) throughout the Cotton Belt, is managed in many areas in part through cultivar resistance. Recently, commercial cotton cultivars modified with genes for resistance to the tobacco budworm (Heliothis virescens F.), to glyphosate herbicide (e.g., Roundup, Monsanto, St. Louis, MO), or in some cases to both the budworm and the herbicide have been released. The objective of this study was to compare the root-knot nematode resistance or susceptibility of several transgenic cotton cultivars with that of their unmodified parent cultivars. The cultivars were evaluated in a field naturally infested with the root-knot nematode and in a growth room in pots infested with the nematode. A dramatic increase in root-knot nematode susceptibility was seen in the transgenic cultivar, Paymaster 1560 BG, compared with its nontransgenic parent, Paymaster 1560. Although only a limited number of cultivars were studied, the data demonstrate that differences in susceptibility to the root-knot nematode exist between some transgenic cultivars and their nontransgenic parents. These data indicate the importance of screening transgenic cultivars for resistance to pests other than the particular pest species targeted by the genetic modification before the transgenic cultivars are recommended for planting.
2. Fungi buildup in glyphosate-treated soybean fields
This new four-year study by University of Missouri reveals a particular impact of glyphosate applications on the soil bio-sphere in Roundup Ready soy crops.
The study shows increases in levels of the fungus 'fusarium' as a result of the introduction of RR soy bean regimes linked to the use of glyphosate. (The fungal genus Fusarium is one of the most economically important groups of fungi causing diseases on a wide variety of plants. Members of the genus are also pathogenic to humans and other animals and a number of species produce very important mycotoxins in food sources - see http://www.rbgsyd.gov.au/RBG/Hortbot/fusarium.html ).
No such study of the impact on soil micro-organisms is being carried out in the UK farm-scale trials of GM crops even though it is suspected that the management regimes introduced by GM herbicide resistant crops may affect soil biology as shown here. This constitutes a major deficiency in the UK farm scale trials. It is, however, not just a problem which affects the UK or one which may be restricted only to environmental impact.
There are also potential economic implications. According to these US scientists: "Right now, that's an ecological assessment that hasn't received much attention. The tests are often limited to small soil insects and earthworms. We think it's been an oversight....potential yield impacts in subsequent seasons due to high soil Fusarium populations, resulting from continued use of glyphosate, needs further investigation...When you think about it, you have to wonder what's happening in the soil."
Healthy functioning of soil micro-organisms is fundamental to long term sustainability in agricultural systems. Even the high-tec farming press not normally associated with a holistic approach to farm management is starting to realise this, albeit rather late in the day: Bill Butterworth, Arable Farming, 25 September 1999, p.16 - 18. ".... Maybe this is what we have glossed over for 25 years; the right soil conditions to unlock the genetic potential of the plant....These mycorrhiza are bound up with plant nutrition and diseases..... The soil is like an enormous rumen, it is similarly complex and it is the plant's 'stomach'.
The connection between this soil rumen and the plant is all the soil micro-organisms and it appears to be substantially the soil mycorrhiza which are the last link in the chain. You can grow plants without them but it is much easier and more secure with them......Those who pay more attention to soil biology get higher yields and lower costs consistently. It does seem clear that not only can we sometimes get close to double the national average yield in a variety of crops, we may be able to do it consistently, across the farm and under a wide range of farming types. The pieces of the jigsaw are beginning to fit into place and it is the balanced management of the soil rumen which is going to deliver." ( For more on this type of approach to land management see: www.btinternet.com/~nlpwessex/Documents/geneticsmyth.htm )
Which governments in the world have taken the trouble to make an in-depth assessment of the potential impacts of transgenic crops and other genetically modified organisms (including the genetically engineered inoculants now sold in the US) on soil biology? The answer is 'none'. This fundamental omission exposes once again the lack of a scientific approach to the introduction of this most radical technology, despite the pious refrains of the various associated academic and commercial interests that we must have a 'scientific debate'. Such refrains are largely a fraud, because they come from precisely the people who know better than anyone else that most of the science hasn't been done. Well before we waste any more time on the debate, let's first have some science.
Dec. 21, 2000
MU researchers find fungi buildup in glyphosate-treated soybean fields
COLUMBIA, Mo. - A four-year study by University of Missouri researchers has found that Roundup herbicide applications change the microbial composition of soil in the field. They observed increases in fungi on the roots and in the soil around the roots of soybean plants, with "potential implications in future management."
"Experiments conducted in 1997 through 2000 at two Missouri locations revealed that Roundup Ready soybeans receiving glyphosate at recommended rates had significantly higher incidence of Fusarium on roots within one week of application compared with" soybeans that did not receive glyphosate, reported Pat Donald, MU plant pathologist, and Robert Kremer, an MU soil scientist and USDA Agricultural Research Service microbiologist.
In research plots at MU Delta Research Center in Portageville, Mo., and at MU Bradford Farm near Columbia, the scientists detected major colonization by several distinct types of the fungus in the glyphosate-treated fields. "Although soil Fusarium populations varied among locations, glyphosate significantly increased numbers at each location."
"There is a natural ebb and flow, but with Roundup Ready beans treated with Roundup, there was always a spike in the levels of the fungi studied," Kremer said.
Fusarium fungi are almost always found in soybean fields, but at elevated levels some can become pathogenic on susceptible plants and lead to lost yields through such diseases as sudden death syndrome and other root rots, Donald said.
Kremer said studies of ecological impact from transgenic plants should include an analysis of effects on the microbial makeup of the soil. "Right now, that's an ecological assessment that hasn't received much attention. The tests are often limited to small soil insects and earthworms. We think it's been an oversight."
"All of the ecological assessment is aboveground," Donald said, adding that such assessments should measure plants' and products' impact on the soil system, "especially if they're going to potentially increase pathogens."
Initially, the researchers believed the increased Fusarium through glyphosate application could provide a biological control for soybean cyst nematode as well as suppressing weed growth. "We thought it might be a double whammy," Donald said. "It didn't work out that way."
She and Kremer emphasized that soybean yields in their experiments were not affected by application of glyphosate as opposed to conventional herbicide treatments. However, "potential yield impacts in subsequent seasons due to high soil Fusarium populations, resulting from continued use of glyphosate, needs further investigation."
Kremer said the study shows the fungi "build up over the growing season. We need to look at it more and see whether there's a buildup of the organism from year to year."
He noted that more than half of Missouri soybeans are Roundup Ready. "When you think about it, you have to wonder what's happening in the soil."
Donald said soil microorganisms such as fungi and nematodes have both detrimental and beneficial associations with crops and the environment. "We need to have all the information that we can."
An abstract of the study can be found at the American Society of Agronomy website: http://www.asa-cssa-sssa.org/cgi-bin/abstract_database_search.cgi?objective=Kremer
Source: Robert Kremer (573) 882-6408; Pat Donald (573) 882-2716
American Society of Agronomy http://www.asa-cssa-sssa.org/cgi-bin/abstract_database_search.cgi?objective=Kremer Title Summary Number: S03-104-P
Herbicide Impact on Fusarium spp. and Soybean Cyst Nematode in Glyphosate-Tolerant Soybean.
Authors: R.J. KREMER USDA-ARS
H.C. MINOR Univ. of Missouri
3. GM Potatoes Alter Soil Ecology
The question arises: Why is this type of testing not being included in the UK field scale trials of GM crops?
"The indigenous bacterial communities of three soil plots located within an agricultural field of 110 m2 were compared. The first site was planted with non-transgenic potato plants, while the other two were planted with transgenic GUS and Barnase/Barstar potato plants, respectively............The statistical treatments clearly revealed spatial and temporal effects, as well as spacextime interaction effects, on the structural composition of the bacterial communities", Max Planck Insitute for Soil Microbiology in Marburg, Germany.
Maintaining the health of soil bacterial communties is absolutely fundamental to sustainable systems of agriculture.
GM Potatoes Alter Soil Ecology
By Virginia Kennedy
A study undertaken at the Max Planck Insitute for Soil Microbiology in Marburg, Germany has revealed that the planting of genetically modified potatoes results in changes to the bacterial communities in soil. The findings cannot say whether or not the observed alterations are detrimental to future plantings on the site of the GM crop, however, the precautionary principle should be used to require that GM crops be removed from field planting until the impact of the ecological alteration is evaluated.
It is known that subtle changes in the microbial ecology can have devastating long term impacts by effecting soil fertility, the availability of nutrients or by creating environments that promote pathogens such as nematodes, fungi or harmful bacteria to flourish. The findings are an early indicator of the need for extensive research on the long term consequences of these changes in soil bacterial communities and their implications for biodiversity.
The study used DNA fingerprinting techniques to study the changes in soil microbes and compared species distribution in soil plots in a control group and following the cultivation of genetically modified potatoes. It proved a powerful technique for characterizing changes in soil microbiology pointing to a way to study the effects of cultivation of GM crops on soil ecology. The technique has not yet been used on the major GM crop releases such as Bt potato, Bt corn, or herbicide tolerant cotton, corn, canola and soybean.
FURTHER INFORMATION : For more information see original paper in FEMS Microbiol Ecol 2000 June 01;32(3):241-247 (ISSN: 0168-6496
Use of the T-RFLP technique to assess spatial and temporal changes in the bacterial community structure within an agricultural soil planted with transgenic and non-transgenic potato plants
Thomas Lukow1, Peter F. Dunfield and Werner Liesack *
Max-Planck-Institut für terrestrische Mikrobiologie, Karl-von-Frisch-StraÃŸe, D-35043 Marburg, Germany
Received 24 June 1999; received in revised form 23 March 2000; accepted 3 April 2000
FEMS Microbiology Ecology, Vol. 32 (3) (2000) pp. 241-247
© 2000 Published by Elsevier Science B.V. All rights reserved.
Abstract The aim of this study was to examine whether the terminal restriction fragment length polymorphism (T-RFLP) analysis represents an appropriate technique for monitoring highly diverse soil bacterial communities, i.e. to assess spatial and/or temporal effects on bacterial community structure. The T-RFLP method, a recently described fingerprinting technique, is based on terminal restriction fragment length polymorphisms between distinct small-subunit rRNA gene sequence types. This technique permits an automated quantification of the fluorescence signal intensities of the individual terminal restriction fragments (T-RFs) in a given community fingerprint pattern. The indigenous bacterial communities of three soil plots located within an agricultural field of 110 m2 were compared. The first site was planted with non-transgenic potato plants, while the other two were planted with transgenic GUS and Barnase/Barstar potato plants, respectively. Once prior to planting and three times after planting, seven parallel samples were taken from each of the three soil plots. The T-RFLP analysis resulted in very complex but highly reproducible community fingerprint patterns. The percentage abundance values of defined T-RFs were calculated for the seven parallel samples of the respective soil plot. A multivariate analysis of variance was used to test T-RFLP data sets for significant differences. The statistical treatments clearly revealed spatial and temporal effects, as well as spacextime interaction effects, on the structural composition of the bacterial communities. T-RFs which showed the highest correlations to the discriminant factors were not those T-RFs which showed the largest single variations between the seven-sample means of individual plots. In summary, the T-RFLP technique, although a polymerase chain reaction-based method, proved to be a suitable technique for monitoring highly diverse soil microbial communities for changes over space and/or time.
Keywords: Biomonitoring; Transgenic plant; Microbial community; Terminal restriction fragment length polymorphism analysis; Genetic fingerprint; Multivariate analysis of variance 1Present address: Fraunhofer-Institut für Umweltchemie und Ökotoxikologie, Auf dem Aberg 1, D-57392 Schmallenberg, Germany.
*Corresponding author. Tel.: +49 (6421) 178 720; Fax: +49 (6421) 178 809
4. GM cotton pest resistance in China
According to experts at the National Cotton Council of America (NCCA) it has been reported that Helicoverpa armigera (Cotton Bollworm) have developed resistance to Bt in two provinces of China. The study suggests that populations of H. armigera were resistant to both Bt and transgenic cotton expressing the Bt toxin.
If field resistance to Bt crops is already occurring in China in advance of their wholesale adoption then this raises major questions regarding the sustainability of the technology.
According to NCCA: "The risk of development of resistance in Bt cotton crops is probably greater than that for Bt pesticide formulations due to continuous and extensive expression of the delta-endotoxin in the plant tissues. Recently it has been reported that Helicoverpa armigera have developed resistance Bt in Yauggu and Xiuxiang provinces of China .... Due to the development of resistance to Bt toxin the average mortality of newly hatched larvae of H. armigera declined significantly as compared to the susceptible strain.... New strategies are needed to maximize the durability and utility of GE cotton." (Report of an Expert Panel on Biotechnology in Cotton - International Cotton Advisory Committee - Nov 2000). [Note: the names given here appear to be those of the counties in two the different provinces of China concerned, NLP Wessex]
The main focus of such strategies to rescue transgenic Bt crops is currently directed at in-crop 'refugia' which are intended to promote the mating of insects susceptible to the toxin with those that may have developed resistance. However, a recent study by French scientists on maize indicated that the principal target pest (European Corn Borer) for transgenic maize varieties incorporating the Bt toxin does not move around within the crop as much as had been anticipated - thereby bringing into further question the likely long term sustainability of Bt transgenic crops in such circumstances.
To what extent this situation might also apply to other pests is not clear. However, in the cotton growing states of the US corn growers are already obliged to plant at least half their corn crops in non-Bt varieties in an attempt to prevent the build up of pests which are common to both corn and cotton crops - corn earworm/cotton bollworm (see: http://www.ncga.com/11biotechnology/insectMgmtPlan/FIG1A.htm ).
Meanwhile genes in pest populations for resistance to Bt "already exist in Australia and perhaps at a threateningly high level" according to the CSIRO Entomology Department in Canberra. Anticipating problems further down the line these scientists report that H.armigera "is capable of resistance of a magnitude that would result in significant, perhaps severe, damage" to Monsanato's transgenic Bt INGARD® cotton (see: http://www.cotton.pi.csiro.au/Publicat/Conf/coconf00/AREAWIDE/25/25.htm ).
Additional work in Australia indicates that the Bt resistance gene may be dominant and not recessive http://www.cotton.pi.csiro.au/Publicat/Conf/coconf00/AREAWIDE/23/23.htm ) further adding to the complications in current attempts to keep the technology alive.
One measure of sustainability in agricultural systems is simply: "can you keep on doing it?". The answer to this question in relation to the use of transgenic pest resistant crops looks increasingly like "no".
The contrast between the on-going degeneration of efficacy in agricultural systems using transgenics (for more information see:http://www.btinternet.com/~nlpwessex/Documents/gmagric.htm ) compared with, for example, the astounding success of a more holistic system of agriculture recently introduced in China (reported in the prestigious journal 'Nature' http://www.nature.com/cgi-taf/DynaPage.taf?file=/nature/journal/v406/n6797/ f ull/406681a0_r.html&filetype= ) is an important indicator of the direction in which global agricultural research priorities need to be redirected.
1. Shen, J.L., Zhen, W.J., Wu, Y.D., Lin, X.W., Zhu, D.F., Zhar W.J., Win, Y.D., Lin, X.W. and Zhu , X.F. 1998. Early resistance of Helicoverpa armigera (Hubner) to Bacillus thuringiensis and its relation to the effect of transgenic cotton lines expressing BT toxin on the insect. Acta Entomologica Sinica 41: 1, 8-14. [Abstract Below]
TI: Early resistance of Helicoverpa armigera (Hubner) to Bacillus thuringiensis and its relation to the effect of transgenic cotton lines expressing BT toxin on the insect.
AU: Shen-JinLiang; Zhou-WeiJun; Wu-YiDong; Lin-XiangWen; Zhu-XieFei; Shen-JL; Zhou-WJ; Wu-YD; Lin-XW; Zhu-XF AD: Department of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China. SO: Acta-Entomologica-Sinica. 1998, 41: 1, 8-14; 17 ref. PY: 1998 LA: Chinese LS: English AB: Susceptible bioassay base line and discrimination concentrations were determined for Bacillus thuringiensis (B.t.) on a susceptible (SUS1) strain of Helicoverpa armigera using the diet infection method. Susceptibilities to commercial B.t. subsp. kurstaki formulations in newly-hatched larvae of H. armigera collected from 6 counties of 5 provinces in China were tested in 1995. Results indicated that populations of H. armigera from Yanggu (Shadong), Handan (Hebei), Xinxian (Henan), Xiaoxian (Anhui) and Fengxian (Jiangsu) showed clear resistance to B.t.. The LC50s increased slightly but the slope (b) decreased significantly compared with that of the susceptible strain. However, the Dongtai population (Jiangsu) remained susceptible. Resistance to B.t. was diagnosed for the first time. The effects of transgenic cotton lines expressing B.t. toxin on various populations of H. armigera using the leaf bioassay were also determined. The average mortality of newly hatched larvae of H. armigera (Yanggu and Xinxiang) with early resistance to B.t. declined significantly (16-29%) compared with those of the susceptible strain. It is suggested that populations of H. armigera from Yanggu and Xinxiang were resistant to B.t. and transgenic cotton expressing B.t. toxin. A resistant management strategy for B.t. is discussed.
DE: entomopathogens-; natural-enemies; microbial-pesticides; transgenic-plants; cotton-; insecticide-resistance; gene-expression; toxins-; bioassays-; mortality-; transgenics-; formulations-; pathogens-; fibre-plants; agricultural-entomology OD: Bacillus-thuringiensis; Helicoverpa-armigera; Gossypium-hirsutum; arthropods-; Gossypium- GE: China- BT: Bacillus; Bacillaceae; Firmicutes; bacteria; prokaryotes; Helicoverpa; Noctuidae; Lepidoptera; insects; arthropods; invertebrates; animals; Gossypium; Malvaceae; Malvales; dicotyledons; angiosperms; Spermatophyta; plants; Developing-Countries; East-Asia; Asia CC: FF600; HH100; WW000 PT: Journal-article
Proc R Soc Lond B Biol Sci 2000 Jun 22;267(1449):1177-84
Host-plant diversity of the European corn borer Ostrinia nubilalis: what value for sustainable transgenic insecticidal Bt maize? Bourguet D, Bethenod MT, Trouve C, Viard F
The strategies proposed for delaying the development of resistance to the Bacillus thuringiensis toxins produced by transgenic maize require high levels of gene flow between individuals feeding on transgenic and refuge plants. The European corn borer Ostrinia nubilalis (Hubner) may be found on several host plants, which may act as natural refuges. The genetic variability of samples collected on sagebrush (Artemisia sp.), hop (Humulus lupulus L.) and maize (Zea mays L.) was studied by comparing the allozyme frequencies for six polymorphic loci. We found a high level of gene flow within and between samples collected on the same host plant. The level of gene flow between the sagebrush and hop insect samples appeared to be sufficiently high for these populations to be considered a single genetic panmictic unit. Conversely, the samples collected on maize were genetically different from those collected on sagebrush and hop. Three of the six loci considered displayed greater between-host-plant than within-host-plant differentiation in comparisons of the group of samples collected on sagebrush or hop with the group of samples collected on maize. This indicates that either there is genetic isolation of the insects feeding on maize or that there is host-plant divergent selection at these three loci or at linked loci. These results have important implications for the potential sustainability of transgenic insecticidal maize.