[For further information on the Electronic Forum on Biotechnology in Food and Agriculture see the Forum website.
Note, participants are assumed to be speaking on their own behalf, unless they state otherwise.]

-----Original Message-----
From: Biotech-Mod2
Sent: 02 April 2007 16:28
To: 'biotech-room2@mailserv.fao.org'
Subject: 72: How can biotechnology help in addressing water scarcity?

This is from Professor C.S. Prakash, Tuskegee University, United States. I have followed with interest and appreciate the comments made to date on the FAO e-mail Conference 14 on Water Scarcity and Agricultural Biotechnologies. The discussion has raised four points that should be addressed.

First, the track record of plant biotechnology providing benefits to farmers in developing countries is good. Although it is true that most of the current biotechnology products were developed in industrialized countries by the private sector, ninety percent of the farmers using biotech products today are in developing countries, and this technology brought them more than US$2.5 billion in increased net income in 2005 alone. We could consider this as some indication of how a drought-tolerant biotech product might further benefit these farmers, especially in places where drought steals away entire harvests every seven or eight years.

Second, I agree that the various plant science disciplines should be working together (Message 55, by Hubert Dulieu). I'd like to point out that marker assisted breeding has been successfully used in agriculture for many years. The key advantage to this technology is the time savings to introgress traits from one genetic background to another - important indeed given the urgency with which we all want to make advances in this area. This is a powerful technology that helps bring plant breeding even closer to plant biotechnology.

Third, the private sector is actively developing technology to deliver drought tolerance in crop plants and making great progress. This is not intended to result in crop plants grown under extreme desert conditions. But several years of field trials are now complete showing a yield advantage with this biotech drought tolerant trait under both water adequate and water stress conditions. It seems likely that such a trait will be available to farmers in the US in the next few years. The advanced state of work in this area leads me to believe it should have some priority among technologies being developed or adapted to mitigate drought conditions in developing countries.

Finally, plant biotechnology is one of many approaches to address water scarcity, and we should be pursuing these different approaches together according to our strengths. We should be thinking of these approaches as complementary, rather than 'alternatives'. To exclude biotechnology -- or any other approach that has been mentioned here -- as part of the solution for water scarcity could either result in slower progress or outright inability to find an adequate solution to this problem. Once we do find solutions that work, we have a responsibility to partner together to evaluate them for different local contexts and ensure that they are accessible, affordable and appropriately used (as mentioned by Gian Nicolay in Messages 41 and 61, and Edo Lin in Message 62). As water demands escalate, this problem will only become more profound if all technological and institutional resources are not used to find this solution.

C.S. Prakash
Professor, Tuskegee University
Tuskegee, AL 36088,
USA
Prakash (at) tuskegee.edu
http://www.agbioworld.org/

-----Original Message-----
From: Biotech-Mod2
Sent: 02 April 2007 16:29
To: 'biotech-room2@mailserv.fao.org'
Subject: 73: Biotech approaches to water stress in developing country crops

From Denis Murphy, University of Glamorgan, Wales, UK (1).

Much has been made of the potential for genetic engineering for the improvement of drought tolerance in crops and this prospect is a major aspect of the biotech industry case for more extensive use of agbiotech in developing countries (2). However, as many researchers in the field have pointed out, our limited knowledge of stress-associated metabolism in plants still constitutes a major handicap to effect such manipulations in practice (3). Another problem that farmers and breeders have long been aware of is the synergistic effect of different stresses on crop performance. It is often the combination of such stresses that is so deleterious to the crop in an agronomic context, rather than effect of any single type of stress. However, molecular biologists have tended to focus (for understandable reasons) on single stresses. Unfortunately for this piecemeal approach, recent studies have shown that simultaneous application of several stresses gives rise to unique responses that cannot be predicted by extrapolating from the effects of stresses given individually (4). Because the co-presence of several stresses is the norm in the open environment, the success of a molecular approach to stress remediation in crops will require a broader and more holistic approach than we have seen hitherto.

Salt tolerance (which is closely related to water stress) has been a particular focus of claims for significant results from transgenic approaches. One of the key prerequisites for the success of a gene insertion strategy to combat salt tolerance is that it should be regulated as a simple genetic trait, i.e. one involving a very small number of genes. Although such simple genetic regulation has been claimed in some cases in experimental studies (5), it seems more likely that salt tolerance in most crops in the field is in fact a rather complex multi-gene trait (6). Meanwhile there have been some successes at engineering salt tolerance in laboratory situations. One example is a transgenic tobacco line, expressing an E coli mannitol-1-phosphate dehydrogenase gene that accumulates elevated levels of mannitol, and can withstand high salinity (7). Laboratory and small-scale field studies have also shown that the accumulation of other compounds, including betaine or trehalose, in transgenic plants may enhance salt tolerance (8). In a University of California (UC) Davis study, rapeseed plants expressing an Arabidopsis vacuolar transport protein tolerated as much as 250 mM sodium chloride (about half the concentration of sea water and enough to kill most crops) without significant impact on seed yield or composition (9).

However, it is not clear whether such relatively simple modifications will lead to a sustained effect on crop yields in the much more complex real-world cropping systems, where osmotic stress is often linked with a combination of other factors such as periodic aridity, mineral/salt build up and/or erosion. This means that the jury is still very much out on the amenability of salt tolerance in the field (which is the only type of interest to breeders) to modification by genetic engineering (10). Unfortunately, attempts to improve salt tolerance through conventional breeding have also met with very limited success, largely due to the complexity of the trait. In the meantime, we know that salt tolerance must be an especially complex trait, physiologically speaking, because there are so many naturally occurring tolerance mechanisms in salt-adapted plants in the wild. This should lead to some caution when interpreting claims in the scientific literature that the transfer of one or a few genes can increase the tolerance of field crops to saline conditions (11). The way forward here is to investigate as many realistically promising strategies as possible, but if I were a practical field breeder with limited resources, and our present state of knowledge, I would probably focus most of my resources on non-transgenic approaches to salt tolerance.

Drought tolerance, like salt tolerance, seems to be controlled by complex sets of traits that may have evolved as separate mechanisms in different groups of plants. In the near future, it is likely that aridity will increase around the world. This will be caused by factors such as lower rainfall due to climate change, and the diversion of upstream water supplies from rivers, e.g. for dams or irrigation, leaving farmers in downstream regions bereft. It is surprising therefore that there have been relatively few attempts to produce transgenic drought-tolerant crops, even by publicly funded organisations. An Australian group has recently reported that a single gene, called erecta, might regulate much of the genetic variation for drought tolerance in the model plant, Arabidopsis (12). This approach merits further attention, but as with salt tolerance, it may turn out that in a practical field situation many other genes are involved in addition to erecta or its equivalents.

Instead of transgenesis it is now possible to use advanced breeding methods to improve the agronomic performance of existing drought tolerant crops in arid regions. One of the most important such crops is pearl millet, which is grown on over 40 million hectares in Africa. The similarity in gene order, or synteny, between the pearl millet genome and that of the other major cereals (13) means that drought-tolerance traits could be introduced into local varieties via marker-assisted conventional breeding. Another option is to use wide crossing and tissue culture methods to cross millet with one of the other high-yielding cereal crop species to create a new drought-tolerant, high-yielding hybrid species. Indeed, breeders have already used such a strategy to create the new rye/wheat hybrid species called Triticale. A further approach is to investigate the possibility of domesticating potential food crops that are already drought tolerant. Once again, knowledge gained from genomics can be applied using molecular markers to accelerate the selection of agronomically suitable varieties of such plants. The timescale of all these approaches will be in decades but surely such research is worthy of more attention by public sector bodies – possibly with the assistance of far-sighted philanthropic donors such as the Gates Foundation?

Denis Murphy,
Biotechnology Unit,
Division of Biology,
University of Glamorgan,
Treforest CF37 1DL,
United Kingdom
Phone: +44 1443 483747, Fax: +44 1443 482285
e-mail: dmurphy2 (at) glam.ac.uk

-----Original Message-----
From: Biotech-Mod2
Sent: 02 April 2007 16:30
To: 'biotech-room2@mailserv.fao.org'
Subject: 74: The role of aquatic weeds in cleansing water

This is Prof KV Peter, again.

I come from a village called Kumbalangi, Cochin, Kerala. There was no tap water system in the village till 1975. Women from the neighbourhood came to my house and collected water in earthern pots from an open pond. Many times the women entered the pond barefoot. On my insistance, a bamboo bridge was made over the pond at one end and the women were requested to collect water standing on the bridge. The pond was full of floating aquatic weeds like pistia and salvenia. As the drinking water was collected in earthen pots, the water was cool enough to drink during summer. No serious incidence of water-borne diseases was reported. Near to my house, there is an island called Kallancherry surrounded by brackish water. But water from open ponds were potable. It is worthwhile to study the role of aquatic weeds in cleansing water.

Prof KV Peter Ph D
Professor of Horticulture
Kerala Agricultural University
KAU -PO, Vellanikkara,
Thrissur, Kerala State
India - 680656
kvptr (at) yahoo.com

-----Original Message-----
From: Biotech-Mod2
Sent: 02 April 2007 16:31
To: 'biotech-room2@mailserv.fao.org'
Subject: 75: Arsenic contamination in agriculture water

This is Professor S.K.T. Nasar, India, coming back to the arsenic contamination issue I addressed in Message 1.

Sanyal and Nasar (2002, 2003 and 2005) showed that arsenic contamination in agriculture is a water-related disaster jointly with droughts, floods or other unwanted conditions. Nasar et al. (2003) indicated how arsenic-contaminated hazardous agricultural products lose marketability under Sanitary and Phytosanitary Measures. (References to these articles are given below). Developing countries oblivious of the consequences focus chiefly on additional rather than on clean food in the face of the globalised open market economy and their rising populations. We firmly believe that both the quantity and quality of irrigation water-to-food continuum warrant equal importance.

The widespread arsenic (mainly As III) contamination of groundwater-irrigation water-soil-crop-animal-human continuum is a global concern. Soil is an effective sink and absorbs arsenic thereby reducing its entry into the food web. A number of weedy flowering and nonflowering plant species, crop varieties, bacteria and cyanobacteria that absorb high amounts of As III are recorded. Published work and our experience propose that arsenic contamination of soil is reduced by hyperaccumulator species of plants. Pteris vittata, a fern, is a well known example. Developing countries can and should identify location-specific hyperaccumulators as we are doing in West Bengal, India, for use in phytoremediation options for contaminated soils.

We recommend the use of green water for irrigation purposes. Where there is no alternative to using As-contaminated ground water for irrigation, it is recommended that this blue water should first be ponded for 24-72 hours before use in irrigation. Arsenic sinks to the benthos during ponding. The mechanism is unclear. Empirical evidence indicates that suspended soil particles, organic matter, phytoplankton and zooplankton hyperaccumulate arsenic from the ponded water thereby leaving it with substantially reduced contaminant load. Suspended particles and dead plankton settle to the bottom taking along the absorbed or adsorbed arsenic compounds. [The term 'benthos' refers to the organisms that live on or in the bottom of a body of water...Moderator].

There are, however, pitfalls in such non-rDNA (recombinant DNA) technologies. The toxic arsenite species is very slowly, if at all, converted into the less toxic arsenate compounds or to the least toxic volatile arsine forms. Most developing countries lack adequate resources of infrastructure and expertise for large scale monitoring of arsenic species in ecosystem components. Dumping of the after-use hyperaccumulating organisms or the filtrates where arsenic filters have been used is another predicament. Toxic arsenic is thrown back to the ecosystem if not dumped properly. Dumping by deep burial of after-use hyperaccumulating organisms in steel capsules is too costly for developing countries. Other protocols are required.

Large scale affordable rDNA technology application for remediation of arsenic contamination is not available. Genes and genetic systems vis-a-vis arsenic resistance and conversion in bacterial species are well documented. Sporadic reports on higher plants and humans are appearing with a rising frequency. It is now noticeably possible that large scale application protocols of gene construct, transformant and transgenic plant for conversion of toxic arsenic compounds will soon become globally available. At present, developing countries should opt for collection, identification and large scale use of organisms that hyperaccumulate and convert arsenic species. More efficient microbes should be selected and put back together into arsenic-contaminated ecosystems for horizontal gene transfers (HGT; equivalent to naturally occurring rDNA processes) to work. A gene hunt for desirable genomes of reharvested microbes from time to time will yield gene reconstructs that will be location specific and in the public domain. It is well documented that different bacterial species contain genes for resistance to arsenic while some are also known to convert arsenic species, say from As 3 to As 5. I believe that if these (species) genomes are placed together in high-arsenic environments, HGT will naturally create over time new genomes harboring both resistance and conversion genes together. This may not appear to be much of a science but has been happening in nature throughout evolutionary history of organisms. HGT happens among bacterial species in just hundred to thousand generations. Dhankher et al. 2002 reported rDNA engineered Arabidopsis thalliana for arsenic phytoremediation (http://www.genetics.uga.edu/rbmlab/pubs.html). This opens up the possibility of producing plant species for a similar purpose. However, in the present context, I recommend current non-rDNA options for developing countries and that they should simultaneously create infrastructure and expertise in rDNA technology options.

Selenium contamination together with arsenic contamination in groundwater is reported. Multiple contaminations are fast appearing as the rule rather than the exception. This creates complexity for rDNA technology application in this context. Reduced quantity of irrigation water, selection of varieties containing lesser amounts of embedded water and the combined use of traditional and rDNA biotechnologies form the current option for developing countries. We believe that similar strategies are applicable for different contaminants and locations.

Prof. S.K.T. Nasar,
Visiting Professor (Genetics),
Department of Environmental Science,
University of Burdwan
West Bengal
India
sktnasar (at) hotmail.com

-----Original Message-----
From: Biotech-Mod2
Sent: 02 April 2007 16:32
To: 'biotech-room2@mailserv.fao.org'
Subject: 76: Use of mycorrhizal fungi

This is S.K.T. Nasar, India, again with comments on the issue of mycorrhizal fungi addressed in my message 1.

Arbuscular mycorrhizal fungus (AMF; formerly VAM) association with the roots of terrestrial plants is known for a long time. The practice of transferring saplings along with rhizosphere soil is age old. The method, in effect, relocates AMF and other soil biota. Endo- or ecto-mycorrhizal association of AMF (Phycomycetes; Glomaceae family) with the roots is universal but contrary to common belief is non-specific or very loosely specific. AMF actually extends the reach of the roots and acts as tiny conduits for the availability of phosphate, other minerals and water. In drier soils the fungal hyphae extend beyond the root zone.

Our simple protocol to monitor AMF includes: digging out the rhizosphere soil with intact undamaged roots; putting them in a bucket with slow flowing water to remove soil to the maximum extent; roots are carefully taken out and cautiously washed; mycorrhizae (root + fungus) are immersed in 0.5% acetic acid solution to loosen tightly attached soil particles; fixing mycorrhizae cut into smaller pieces in a 1:1 acetic ethanol solution; and observing unstained or stained mycorrhizae under a microscope. Our experiments with litchi (lychee), cereals, vegetables and weeds showed that different AMF genera and species may simultaneously infest different roots of the same plant. We also found in an unpublished observation that one fungal hypha interconnected roots of two different species. These data lead us to the non-specific association of fungus and root. Mycorrhizal fungus always grows in association with actinomycete fungi. The relevance of this fungus-fungus association is not understood by us.

Quantification of water made available to the host roots is absent. Scientists claiming to increase water availability by infusing selected mycorrhizal fungal strains into the rhizosphere have not traced its growth in cropped soils. Experimenters need to 'see' AMF in action.

Our study on the cytology of mycorrhizal fungi of lychee and sweet potato did not lead us far. Molecular biology of specific relationship between AMF and plant roots is not fully understood. At present, recombinant DNA (rDNA) biotechnology of mycorrhizal fungal association needs more ground work. The present option is to refine the age old protocol and use them to advantage. Developing countries need rDNA expertise to embark upon mycorrhizal biotechnology to use AMF on a mass scale for growing water-requiring plants within a defined range of dry soils. A beginning must be made now.

Prof. S.K.T. Nasar,
Visiting Professor (Genetics),
Department of Environmental Science,
University of Burdwan
West Bengal
India
sktnasar (at) hotmail.com

[Specificity of the plant-fungus association seems to vary with the type of mycorrhizal fungi. As written in Section 5b) of the background document: "Mycorrhizae are symbiotic associations that form between the roots of plant species and fungi (see e.g. Sylvia et al, 2005). The hyphae (thread-like structures that are part of the body of the fungi) spread through the soil, taking up nutrients such as phosphorus and absorbing water, and transporting them to the plant root, and in return the fungi receive sugars from the plant. Almost all plant species form mycorrhizae. A number of different types of associations exist, of which arbuscular mycorrhizae (AM, also called vesicular-arbuscular mycorrhizae [VAM]) and ectomycorrhizae (EM) are the most widespread and economically important. In AM, the hyphae penetrate and grow within the plant root cells. The fungi that form AM are part of the Glomeromycota fungi, involving less than 200 described species, and most crops and forest trees form AM with these fungi which tend to have a broad host plant range. In EM, the hyphae of the fungi do not penetrate the plant root cells and the external surface of the roots is covered by a characteristic sheath of hyphae. Compared to AM, the fungi that form EM are more diverse, involving over 4,000 fungal species (including e.g. truffles), although the range of plant species that form EM is more limited, involving trees from just a few families, including the fir, oak and pine" (http://www.fao.org/biotech/C14doc.htm) ...Moderator].

-----Original Message-----
From: Biotech-Mod2
Sent: 02 April 2007 16:33
To: 'biotech-room2@mailserv.fao.org'
Subject: 77: Using GMO and non-GMO biotechnologies

This is S.K.T. Nasar, India, with a rejoinder on the issue related to organic agriculture to combat water scarcity raised in my message 1.

All crops can be grown during all seasons anywhere in the world under fully protected and automated protocols of precision agriculture. The production cost will, however, be much too prohibitive. Varied agro-ecologies in combination with minimal input for precision agriculture such as irrigation and high yielding varieties provide a comparative advantage to struggling agricultural economy of developing countries. This situation creates, maintains and augments agrodiversity, agricultural biodiversity and biological diversity. Exploitative intellectual property rights (IPR)-protected recombinant DNA (rDNA) biotechnologies will create uniformity and destroy diversity. Upscaled non-rDNA biotechnologies combined with location-specific rDNA biotechnologies are the right strategy for developing countries.

rDNA biotechnologies are certainly an option for enhancement of water use efficiency and for providing uncontaminated irrigation water at the stages of crop husbandry and at post-harvest value addition. Such rDNA biotechnologies are not available for the present. The need to speed up naturally occurring biological processes should receive due consideration.

Microbial fertilisers in conjunction with organic manure/compost in place of substantially reduced or nil doses of chemical NPK fertilisers reduce the amount of irrigation water yet improve crop productivity and quality. Water holding capacity of the soil improves. Interestingly, the seed-to-harvest time is reduced by up to fifteen days for some crops. Informal experiments indicate reduction of embedded water in crop and its products. The lessons learned are: biofertiliser-cum-organic manuring cuts the amount of irrigation water and cuts seed-to-harvest time thereby decreasing the number of irrigations, depending upon the crop, cropping system and agro-ecology. Intercropping, continuous cropping and no tillage cropping systems with well researched combinations are well known agronomic methods to minimise evapotranspiration losses of water. Live mulching with carefully chosen weed or crop species help retain water in agrosystems. The option for developing countries now is to make all-out efforts to simultaneously use speeded up non-rDNA natural processes and develop location specific rDNA biotechnologies as public good.

Prof. S.K.T. Nasar,
Visiting Professor (Genetics),
Department of Environmental Science,
University of Burdwan
West Bengal
India
sktnasar (at) hotmail.com

-----Original Message-----
From: Biotech-Mod2
Sent: 02 April 2007 16:33
To: 'biotech-room2@mailserv.fao.org'
Subject: 78: Re: Conventional breeding vs. new tools for drought tolerance

I am Dr A.K. Gupta from India.

I have read many messages like 62 (by Edo Lin), 65 (by S.K. Samanta) and I am convinced that expensive techniques of molecular biology should be used only when there is no substitute. There is a need for giving more emphasis to biochemical mapping along with physical traits of diverse genetic material avaialable. I am convinced that it is possible to develop a model on the basis of biochemical mapping wherein if 15-20 biochemical parameters, selected carefully, are studied in diverse germplasm, then on the basis of diversity of these parameters it should be possible to propose a model wherein it should be possible to predict if a specific germplasm is going to behave in a specific manner under certain abiotic stress conditions (say drought) with 80-90% certainty without actually going for the field trials.

Dr A K Gupta
Professor of Biochemistry
Punjab Agricultural University
Ludhiana-141 004
India
e-mail: anilkgupta (at) sify.com