Biotechnology helps engineer resistance to rice nematodes |
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| Genetically engineered resistance to rice nematodes | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
An effective and biosafe method of controlling nematode worms in rice is now ready for trials in rice-growing countries. Nematodes are a serious pest in a wide range of crops and the technique is generating a lot of interest, particularly in South Asia, Africa and South America. Tested on a wide range of crops in the USA, China and Uganda, the technology is already being used in both developed and developing-world countries. It has great potential for agriculture in India and China where governments strongly support biotechnology as a way to rapidly raise food production. Project Ref: PSP19:
Research Programmes: Plant Science Research Programme (ID code PSP0032). Relevant Research Projects: Projects R6453, R6948, R7294, R8031 Institutional partners on DFID PSRP grants
Current funding of the biotechnology, but not its application to developing world, includes BBSRC Agrifood committee and its Crop Science Initiative plus NERC Dorothy Hodgkin Studentship for crop environmental biosafety (Chinese national).
This project has demonstrated effective and a biosafe approach to nematode control of rice pests. The approach relies on plant proteins (cystatins) that prevent digestion of dietary plant proteins by the feeding nematodes. Cystatins lack such effects on humans. They suppress the nematode's ability to grow, lay eggs and build to population levels that damage crops. Specific promoters have been developed that ensure the cystatin is expressed where nematodes feed in roots and not throughout the whole plant. This prevents more of these safe proteins occurring in the human diet than naturally present in common foods such as rice and maize seeds. Additional work funded by other donors (DEFRA) has demonstrated that the approach has no environmental impact on a wide range of non-target organisms. The plant biotechnology strategy adopted involved Agrobacterium-mediated transformation and high-throughput molecular screening of clean gene progenies. This was carried out at the JIC by Dr P. Vain. The plants were then sent to Leeds University for molecular characterisation and bioassays against Meloidogyne incognita (the man target species according to expert reports for DFID completed by others that underpinned establishment of this project). Lines were confirmed by Southern blot and qPCR analysis. Single copy transgenic lines plus some containing two or three copies of the cystatin gene were identified. All of these lines were generated using the clean gene technology developed at JIC (see PSP18 on "clean gene technology"). This approach segregates the selectable marker used in selecting lines of interest after the first generation of transformed rice. The aim is to develop homozygous lines expressing the nematode resistance but not the selectable marker. This is often resistance an antibiotic so its elimination aids biosafety in terms of both food and environmental safety. Lines contained different numbers of inserts provide different gene doses and therefore a range of resistance levels. Many plants had a very high level of resistance to M. incognita i.e. >90% resistance obtained and require only final selection of homozygous seeds before donation within the RiUP. In other aspects of the work, root preferential promoters have been developed for rice to limit activity to where nematode parasites of roots occur. In other work, (BBSRC funded) additive resistance has been developed and is available for RiUP. The work provides a key example internationally of how transgenic technology can be adapted to meet the needs of the poor. The outputs of this project have a general value for developing world agriculture and have are received considerable interest in many countries in S. Asia, Africa and S. America.
The main commodity in which the approach is relevant for this cluster is rice. There has been accompanying work on both potato (PSP21) and banana (PSP20) within the RNRRS grants developing this output. The technology is applicable to all crops for which transformation has been achieved. The benefits extend indirectly to other crops when they are grown in close rotation with rice. Nematodes such as Meloidogyne damage a wide range of crops and multiplication on rice can re-dispose follow on crops to damage. This also applies to control of Pratylenchus spp grown rice particularity when other cereals are the follow-on crop. Production Systems: 
These outputs could be clustered with others addressing the safe use of biotechnology for nematode control in potato and banana (R6380, R6743, R7548 and R8031). These project share a similar approach and hence some resources. This biotechnology approach could also be stacked with that for RYMV resistance (R7415, R7548). There is also potential to combine with other plant biotechnology approaches such as marker assisted breeding (R6673, R7080, R7434, R7435, R8200 and R8089). The approach could also be clustered with other approaches such as participatory breeding for rice improvement (R8221, R8099, R6826, R7657, R7434, and R8099). Nematode resistance could be provided in context of other approaches to enhance rice productivity. Priming of upland rice (R7438) is of interest as nematodes damage young plants. There has been some preliminary work between Leeds and Dr D. Harris (Bangor) on the interactions between rice priming and nematodes. How the outputs were validated: Methods of Evaluation The efficacy of the approach were examined thoroughly in containment trials and some of the work for RNRRS has been published in peer review journals and detailed in reports to DFID (see below)
The University of Leeds designed constructs and conducted all glasshouse trials. The Cereal Transformation group of JIC was responsible for development of transformation, and clean gene technology plus production and selection of lines of interest for detailed study. The outputs from the programme were then validated by peer review before publication (see references cited above). The technology for control of nematodes was also validated by demonstrating its efficacy in other crops such as potato (see PSP21) and bananas (see PSP18). The technology is being evaluated in a wide range of crops by USDA, Chinese Academy of Agricultural Sciences, and USAID. There are a range of others interested in developing further this evaluation process. Evidence of demand Our studies for other crops suggest growers welcome the new power of biotechnology and would like to judge the benefits. This pro-science and practical approach is likely to prevail among many developing world growers. We have not studied this issue for rice as it have been thoroughly covered by many others included the DFID chief scientist (G. Conway) and Michael Lipton possibly the UK's most eminent social scientist in this field and a member of the Nuffield, Bioethics commission. The key points are that transgenic crops can raise yield potential and field yields on those difficult low progress areas least touched by the Green Revolution (Conway 1989; The Doubly Green Revolution : food for all in the 21st century. London. Penguin). Upland rice would fall very firmly in that category. Lipton (2001 Journal of International Development, 13, 823-846) is of the view that rice is one crop which can be improved to cheapen or improve stable crops eaten by the poor. The need is traits that have poverty focus and resistance to pests are given as example traits of value. The outstanding issue is the availability of such traits as public goods. More recently it has been reported that poorer nations are attempting to develop public research in this area (Cohen, 2005, Nature Biotechnology, 23, 27-33). Rice is the most frequently transformed crop in this context. A number of developing world research institutes has shown interest in the nematode resistance developed with in the RNRRS/PSRP. They include: WARDA , the Chinese Academy of Agricultural research (Prof Qu) and IRRI In India, recent interaction has been with the Indian National Agricultural Research Institute in Delhi. This fits well with there funding to Leeds from FCO/Indian government for collaboration between Leeds and IARI. Discussions with nematologists at IARI, confirmed severe nematode problems in much of the northern India's rice/wheat cropping system. We are exploring the development of a relationship between the IARI and DFID's India desk. DFID/PSRP is the only international programme that has developed nematode resistance. It represents a distinct UK contribution to global public goods available royalty-free to the Research into Use Programme. Clearly all the factors are in place that to bring nematode resistance successfully into use. Where the Outputs were Validated: The outputs have not yet been evaluated in the developing world as RNRRS came to an end coincidently with plants generating seeds for such work. IARI are keen start the process of research into use. Who are the Users? The seeds from the RNRRS programme are safely stored at JIC in a designated facility until they and Leeds University can gain further funds to deliver these important outputs. Where the outputs have been used: Products are not currently being used in rice because of the end of RNRRS funding. The technology has been widely taken up (see earlier) in both developed and developing world countries. Subsequent development of UK agriculture is continuing with strong BBSRC support from both Agrifood committee and The Crop Science Initiative. These outputs could readily flow into the RiUP. Scale of Current Use: Output products are not currently being used in rice. The technology is being evaluated in wide range of crops by USDA (USA), CAAS (China), NARO (Uganda). A visit in Later October 2006 is to develop a basis for transfer of rice and potato to India for evaluation and use their. The technology has been field trialled in the UK but uptake has been delayed by attitudes to such plants with Europe. Policy and Institutional Structures, and Key Components for Success: The biotechnology to be deployed should be shown to be fit for purpose and fully biosafe when expressed in rice. This requires experiment under the field conditions of different rice production systems in the targeted country. This is necessary to establish the benefits and future potential the technology to various stakeholders before uptake is progressed. A careful and thorough analysis of the benefits as well as the apprehensions surrounding deployment of biotechnology is requited to ensure they can benefit the poor. A government that has a pro-biotechnology attitude is essential. The governments of both India and China are committed to facilitating substantial rather than incremental approaches to enhancing food production. We will focus on India. It also has a progressive national biosafety committee/system. It has a number of NARS with a good science capacity and hence the ability to adopt the global public goods and reduce them to use on rice in India. It also has an extension service network able to explain the potential of biotechnology and be involved in its dissemination. It has good contacts with growers willing to support scientific improvements whose successes favour diffusion to further growers. The input of social scientist is important to support the process, assess uptake and determine safe dispersal to the informal seed system so extending to the poorer sections of the grower community. Lessons Learned and Uptake Pathways Promotion of Outputs: Output products are not currently being used in rice. The technology is in pre-commercial development in USDA labs in Hawaii, it is being trialled at Institute of Vegetables and Flowers (CAAS), Beijing. Agreements are in place to extend this to Soybean in China (CAS, Beijing) and Coffee in Brasil (University of Campos dos Goytacazes, Brasil). Other technology being developed with BBSRC funding is being developed commercially by Monsanto and could be available for use in rice by DFID on a royalty-free basis. Potential Barriers Preventing Adoption of Outputs:
How to Overcome Barriers to Adoption of Outputs: A key need for development of plant biotechnology is to appreciate that large gains can be achieved if continuity of effort is maintained to realise them. This type of work does not lend itself to a short-term approach and the ending of the RNRRS programme ended continuity on nematode resistant rice. The translational research period requires similar consistency of effort. The issue is that many options offered to DFID lack the power to make substantial improvement to food security. Although they are relatively inexpensive, they will have little positive impact on world food security. In contrast, plant biotechnology has high research power and can deliver a wide range of benefits to very many people through the simple act of seed distribution. The impact and need for plant biotechnology is evident from the investment that China is making using its strong science base. India would benefit from support from the UK science base. The distinct DFID funded nematode resistance rice is clearly an opportunity make substantial improvement to rice production in that county and elsewhere is S. Asia later. Lessons Learned:
Poverty Impact Studies: There have been a number of studies by eminent scientists and social scientists on the general issue of plant biotechnology and its benefits for the poor. Examples are listed below. The specific issue of the benefits from nematode resistance have been considered (Atkinson H.J. et al., 2005, Aspects of Applied Biology 75: 109-114 and Atkinson H.J. et al. ,2001, Trends in Biotechnology 19, 91-96). There have been both general considerations. Examples include:
How the Poor have Benefited (including gender and other poverty groups): The principal uptake of plant biotechnology to-date in India is for Lepidopteran resistant cotton using cry genes (Bt). Extensive work in than country identifies how losses from insects are such that the value of the approach in cost saving to USA growers does not provide a paradigm for India. Here the levels of damage are more severe and there are less control options (Qaim & Zilberman, 2003, Science 299, 900-902). This analysis can be extended to nematode control. In this case, there are no options for the grower apart from reducing the intensity of cropping or rotating away from their rice crops to less favoured alternative. In addition, most growers are unaware of the damage caused and do not even attempt to take rectifying action. Therefore, the a priori case is that nematode resistance is exactly the sort of trait that will benefit resource poor farmers if made available to them without adding costs. It has the potential to control nematode without change to favoured cropping practises. To date, no GM rice has been released / commercialized worldwide. The impact of GM rice on poverty is therefore difficult to assess. However, insect resistant B.t. rice is at a pre-commercialisation stage in both Iran and China (C. James, 2005, Global status of commercialized biotech/GM crop, ISAAA brief 34). The golden rice (http://www.goldenrice.org/) fortified with pro-vitamin A is also in the pipeline for release in Asia. Second generation golden rice plants containing c30µg provitaminA per gram of endosperm protein (i.e. 60g of golden rice now meets daily need) are currently grown at IARI (India). Direct and Indirect Environmental Benefits: More agrochemicals are used on rice than on all other crops combined in the major rice-producing countries of Asia. Many of the compounds are outmoded chemicals banded from others part of the world. Nematicides are not commonly applied to rice although this use could grow as development occurs. The real issue is that alternatives to chemical control are needed that do not reduce the intensity of rice production or impose unwanted change to agricultural practices. Biotechnology has the potential to deliver alternative approaches to chemicals that growers can depend upon. There are therefore important what in shifting the mind set of many growers from an inclination to be pesticide dependent when resources allow to an equally effective but environmentally benign basis for crop protection and improvement. Adverse Environmental Impacts: The approach will have no adverse environmental impact. All plants to be released will be biosafety and the removal of the selectable maker via clean-gene technology (see PSP18) will meet apprehension of some in relation to use of antibiotic or herbicide resistance as selectable markers. Coping with the Effects of Climate Change, or Risk from Natural Disasters: The outputs will enhance the ability of poor people to cope with droughts associated with climate change. The principal, direct consequence of nematode damage is to stunt root systems. This ensures plants are less able to obtain water and nutrients from soil. Common symptoms of attack are wilting and mineral deficiencies. This issue is very apparent for rainfed, upland rice. The effect is evident for other crops to which the plant technology could be applied later once biosafety is assured. Relevant Research Projects,
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