"Georgia Unknown"

New US 'mystery' corn viruses - is GM the prime suspect?

(the internet address of this page is www.btinternet.com/~nlpwessex/Documents/NewUScornviruses.htm)

29 January 2001

What has caused these two new corn viruses - which continue to baffle crop scientists - to emerge simultaneously in the US (see Ohio State University report below)?

Back in 1994 when Calgene's GM Flavr Savr tomato was first commercialised Dr. Joseph Cummins, Professor Emeritus in genetics from the University of West-Ontario, Canada, warned the biotechnology community:

"Probably the greatest threat from genetically altered crops is the insertion of modified virus and insect virus genes into crops. It has been shown in the laboratory that genetic recombination will create highly virulent new viruses from such constructions. Certainly the widely used cauliflower mosaic virus [CaMV] is a potentially dangerous gene. It is a pararetrovirus meaning that it multiplies by making DNA from RNA messages. It is very similar to the Hepatitis B virus and related to HIV."

What is 'interesting' now about the new corn viruses that have suddenly arrived in the US is that:

1.  One of them is considered to be a particular 'mystery' as it has the characteristics of a tomato virus, not a grain crop virus, and the other remains unidentified.

2.  The particular item of concern to Professor Cummins back in 1994 regarding the Flavr Savr tomato (see http://home1.swipnet.se/~w-18472/jccamvir.htm ) was its incorporation of a genetic sequence from the Cauliflower Mosaic Virus.

This material is now used in most types of GM crops (i.e.those incorporating recombinant DNA) that have already been approved for commercial use, including corn varieties grown in the US.  The material is in a novel form which allows it to operate in a wide range of host genetic environments which otherwise would not be possible in its natural state.

The question arises as to whether the widespread use of this promiscuous viral element could contribute to the creation of some kind of pathogenic bridge, BSE style, between different plant viruses and their host species.

3. Is it a coincidence that two new corn viruses should emerge simultaneously a short time after the introduction of GM corn and other crops incorporating the CaMV promoter? 

Professor Cummins has subsequently cited an alarming list of references documenting the phenomenon of 'viral recombination' arising with such transgenic constructs
(see: http://www.natural-law.ca/genetic/NewsMar-Apr99/GEN4-24JoeVirusMonsn.html ).

The UK's leading plant biotechnology laboratory, the John Innes Centre, has since published research confirming that the CaMV promoter has a 'recombination hotspot'.  According to the John Innes Centre Annual Report 1998/99, p 22-23:

"Transgene rearrangements often occur at regions rich in DNA secondary structure, such as the CAMV 35S promoter, which can form the cruciform structure shown above.  This allows recombination to occur......"

4. It is clear that plant pathologists in the US don't know what is going on with the arrival of these two new corn viruses despite 18 months work on at least one of them.

5. If a GM linkage were to be found with the new corn viruses would the authorities dare tell us or would the discovery get the 'Pusztai' treatment (despite calls from the Royal Society to do so, no-one has ever dared try and repeat Dr Pusztai's experiment on the recombinant DNA potatoes concerned in case it confirmed what Dr Pusztai had concluded)?

In this context it is worth remembering that George W. Bush's new Agriculture Secretary, Ann Veneman, was previously a director of the Californian biotechnology company, Calgene, which developed the Flavr Savr tomato - the first commercial recombinant DNA crop to incorporate the Cauliflower Mosaic Virus promoter (for more details on Veneman's agri-trade background see: http://www.calbar.org/2sec/3bus/4agri/data.htm ).

Meanwhile concerns regarding the unknown causes of the new corn viruses in the US can only be based on speculation at this stage in the absence of a verified explanation.  

Nonetheless, in accordance with the precautionary principle, it is worth considering the reflections of other scientists on the possibility of the creation of new diseases through the introduction into the environment of recombinant DNA organisms  (RDOs) which incorporate transgenic viral sequences:

"..... At a meeting in Washington DC last week, the US Department of Agriculture outlined possible restrictions aimed at reducing the risk of creating harmful new plant viruses [despite this meeting being held back in 1997 these restrictions have not since been implemented to the best of our knowledge: NLPWessex] .....  

These include a possible limit on the length of genetic sequences introduced into crop plants and the banning of genes that make functional proteins. The department is also worried about particularly high-risk sequences, such as those that trigger the process of viral replication.  

Advocates of the technology argue that there is no evidence that recombination - swapping genetic material between viruses - will produce dangerous hybrid viruses....  

The technology's proponents claim that if recombination were likely, new hybrid viruses would be turning up all the time."

New Scientist magazine, 16 August 1997: 'Field of genes: They have the biotechnology, but it may be running out of control, and the US is starting to worry'

  ".......The area of concern specific to viral transgenes is the potential risks on any interactions between the viral or virus-related sequences being expressed from the transgene and another virus superinfecting that plant.....   Three sorts of recombination have been recognized (20): homologous with crossovers between related RNAs at precisely matched sites, aberrant homologous with crossovers between related RNAs not at corresponding sites, and nonhomologous with crossovers between unrelated RNAs at noncorresponding sites. There is considerable evidence for extensive recombination in RNA viruses (see refs. 20 and 21 for details), and probably all three mechanisms have been involved at one time or another. It is generally considered that recombination plays an important role in the evolution of RNA viruses (see refs. 20-23).....................

All the experimentation on recombinants between plant virus sequences has been done in controlled laboratory situations. It is difficult to devise detailed protocols for the detection of recombinants produced in the field...........

For small-scale releases, it is relatively easy to design monitoring procedures ......... for detecting heteroencapsidants or recombinants. This will be much more difficult, if not impossible, for large-scale releases, in which the approach should be to educate farmers and extension service personel to identify any unusual event that might be associated with transgenic plants. This will be the challenge for the future."

Hull R. (1998) 'Detection of risks associated with coat protein transgenics'. In: Methods in Molecular Biology: Plant Virology Protocols: from Virus Isolation to Transgenic Resistance (Eds: Foster G.D., Taylor S.C.). New Jersey, Humana Press Inc. 81, 574-555.

"FIVE years ago, New Scientist asked biomedical researchers if they thought genetic engineering could make a virus or bacterium more virulent than nature's worst. They replied that it would be difficult if not impossible, and would need a colossal research effort. Now it's clear they forgot one thing -- the unexpected.

Adding the gene turned a merely nasty virus into a killer......

There's also the problem that many biologists choose to ignore biotechnology's threats. New Scientist has found that neither researchers nor biological societies are keen to discuss the misuse of genetic engineering -- not least because they fear a backlash against their work. But this attitude must change or biologists will find themselves sidelined when the first really dangerous incident takes place.

......leaving things as they are is not an option. Biotechnology is beginning to show an evil grin. Unless we wipe that smile from its face, we'll live to regret it".

New Scientist magazine, 13 January 2001: 'The genie is out. Biotech has just sprung a nasty surprise. Next time, it could be catastrophic' - editorial on the creation of a new more virulent virus by mistake by genetic engineers which wiped out laboratory mice in Australia.

Finally, special thanks to US farmer Jim Winiger for drawing the discovery of the two new corn viruses to our attention, and of course to Professor Cummins for his continuing forthright efforts to draw the world's attention to viral risks associated with RDOs.

For more on the particular risks associated with the use of the Cauliflower Mosaic Virus promoter in corn and other GM crops see: www.btinternet.com/~nlpwessex/Documents/camv.htm .  

Meanwhile what about the second corn virus - "Georgia Unknown" - that remains unidentified, but which causes disease symptoms characteristic of mosaic viruses?

NATURAL LAW PARTY WESSEX
nlpwessex@bigfoot.com
www.btinternet.com/~nlpwessex

"There is no scientific proof that BSE can be transmitted to man by beef"
National Farmers Union of England and Wales, 1996

OHIO STATE UNIVERSITY, College of Food, Agricultural, and Environmental Sciences.

Ohioline news

http://www.ag.ohio-state.edu/~ohioline/news/11_00/11_21_04.html

November 21, 2000
Two New Corn Viruses Discovered
By Candace Pollock
(330) 202-3550

Source: Peg Redinbaugh
(330) 263-3965
redinbaugh.2@osu.edu

WOOSTER, OH - Ohio State University researchers have discovered two new corn viruses, one of which remains to be identified.

Researchers at Ohio Agricultural Research and Development Center and the USDA have isolated, identified and characterized a virus known as maize necrotic streak virus, based on the symptoms it incites. The findings were published in the October issue of Plant Disease.

Although there have been no recorded reports of the disease and it may not pose a problem for Ohio corn growers, the researchers are taking preventive measures to ensure farmers are well educated.

"We want farmers to know that this virus exists and we are working to make sure that it is never a problem with crops," said Peg Redinbaugh, research plant molecular biologist. Redinbaugh is part of a joint program between OARDC and USDA scientists dedicated to tracking the emergence of corn diseases worldwide. The group, based at OARDC, is responsible for analyzing maize viruses throughout the United States and around the world.

It is estimated that crop losses from maize viruses range between 5-15 percent annually in the U.S. Diseases are responsible for reduction in yield, as well as affecting grain and seed quality.

Maize necrotic streak virus was discovered after the researchers analyzed corn crops from Arizona suspected of being infected with maize dwarf mosaic virus, a disease that has caused severe crop losses throughout the U.S. Further analysis revealed the new virus, characterized by pale green, yellow, or cream-colored streaks on the leaves, which eventually become translucent and necrotic around the edges.

But in some respects, the virus still remains a mystery. It falls into a family of viruses that infect tomatoes and peppers, not grain crops, said Redinbaugh. In the 18 months of studying the virus, researchers have yet to nail down specific vectors of transmission.

"Diseases don't get from plant to plant without some sort of help, whether it be an insect, nematode, or fungus," said Redinbaugh. "Using three different techniques we've only been able to transmit the virus through the soil. And we don't know what's in the soil that transmits the virus." Most plant diseases are transmitted via an insect. The researchers used several common crop insects, such as the corn root aphid, green peach aphid, potato aphid, oat bird cherry aphid, corn leafhopper, black-faced leafhopper, corn planthopper and western rootworm to spread the disease from one plant sample to another. But none of the insects proved to be a vector of transmission. The researchers also attempted to transmit the virus by rubbing healthy leaves with the disease, without success.

Redinbaugh said that the difficulty in transmission might be what keeps the virus at bay. "It may not be a big problem if it's not easily transmitted in nature," she said. "If the virus primarily is transmitted through the soil, like we think, then it could be just a local problem."

Redinbaugh said the researchers have found one corn line that is resistant to maize necrotic streak virus, but the tropical line is not well adapted to Ohio soil. She said molecular markers are currently being developed in the hopes that resistant Ohio corn lines may be identified.

Researchers have also discovered a second corn virus, which has yet to be identified. First discovered in Georgia, Redinbaugh said the virus has similar symptoms to several corn diseases including maize mosaic virus, maize chlorotic dwarf mosaic virus and maize rayado fino, so it can be easily misdiagnosed. Insects, namely planthoppers and leafhoppers, easily
transmit those diseases.

"The Georgia unknown could be a problem if it's transmitted by insects, like the other viruses are," said Redinbaugh. Studies have yet to determine if an insect like the planthopper transmits the unknown virus, but Redinbaugh determines that the virus may not be a likely Ohio invader due to the insect's restricted southern U.S. geographical area. Studies on the "Georgia
unknown" are ongoing.

Other researchers involved in the studies include OARDC researchers Ray Louie, Don Gordon, Dave Fulton, Bill Styer and Saskia Hogenhout and USDA OSU-based researchers John Abt, Robert Anderson and Kristen Willie.  

NLPWessex footnote:  

Below is the scientific reference quoted in the Ohio State University article.  Although we are not able to comment at this type of technical level, particularly as it is new territory, the following observation has been made to us on this subject:  

"The Tombus virus group does tend to take up sequences, possibly from mRNA. In CaMV replication two kinds of RNA are passed from nucleus to cytoplasm; the RNA template for virus replication into DNA and processes messages to make viral capsid. Either could provide sequences for the Tombus virus".

http://www.apsnet.org/pd/summaries/top.asp
Plant Disease October 2000   Volume 84, Number 10, p 1133 - 1139  

Maize necrotic streak virus, a New Maize Virus with Similarity to Species of the Family Tombusviridae.

Raymond Louie and M. G. Redinbaugh, USDA-ARS, Corn and Soybean Research, Department of Plant Pathology, The Ohio State University, Wooster 44691; D. T. Gordon, Department of Plant Pathology, The Ohio State University; and J. J. Abt and R. J. Anderson, USDA-ARS, Corn and Soybean Research, Department of Plant Pathology and Department of Entomology, The Ohio State University.

Accepted for publication 28 June 2000.

Developing knowledge of exotic or emerging virus diseases of corn before they become epidemic allows researchers to devise disease control strategies for the corn seed industry and producers. We examined corn leaf samples, thought to be infected with Maize chlorotic dwarf virus (MCDV), collected in Arizona. Although no MCDV was found in the samples, two other viruses were identified: Maize dwarf mosaic virus and a second virus that had not previously been characterized. The new virus produced severe symptoms on corn that included pale green, yellow, or cream-colored spots and streaks. As disease developed, the spots and streaks became spindle-shaped, then coalesced into long, chlorotic bands that became translucent and necrotic around the edges. The stalks developed a chlorosis that became necrotic. These distinctive symptoms were the basis for the naming the pathogen Maize necrotic streak virus (MNeSV). It could be transmitted using a specialized technology known as "vascular puncture inoculation", but not by leaf-rub inoculation or any of the insects tested. MNeSV had a small isometric particle, high titer in infected leaves, and a genomic structure similar to viruses in the family Tombusviridae. Researchers, extension specialists, and producers can confirm the identity of MNeSV in field samples using a serological assay developed in this study.

More comments on the new US corn viruses from Prof Joe Cummins
Bio-terrorism and the Gill rDNA trajectory