Transgenic banana could feed millions |
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A safe transgenic banana could prevent nematodes (worms) destroying around 6 million tonnes of bananas a year. This is enough to feed the 60 million people in Uganda, Rwanda, Ghana, Nigeria and Cameroon for whom banana is a staple food. Because bananas are sterile, it's very hard to breed resistance to nematodes by conventional plant breeding methods. And the chemicals that are used to control nematodes are harmful both to humans and the environment. The gene introduced into East Highland African Bananas stops the nematodes growing and laying eggs, but does not affect humans at all. This technology is already being used in the UK, and also in Uganda on local cooking bananas. The transgenic method is also being applied to develop nematode-resistant potatoes and rice. Project Ref: PSP20:
Research Programmes: Plant Science Research Programme (ID code PSP0033). Relevant Research Projects: Plant Science Research Programme grants R6743 and R8031. Institutional partners
The output is both a technology and a product and was generated over the 2002-2005 period. The technology enables the reliable production of banana embryogenic callus and cell suspension cultures, which can be used for genetic transformation. This technology has been optimised for East Highland African Bananas (EHAB). These are AAA cooking bananas which represent the staple food for millions of people in Africa. Unfortunately, most EHAB are recalcitrant to callus and cell culture in vitro and cannot be genetically transformed. The output from this programme provides for the first time - worldwide - a technology enabling the transformation of EHAB. Banana plants are grown in glasshouses at the John Innes Centre (Norwich, UK), immature inflorescences are harvested and cultured in vitro to produce embryogenic callus, which is then dispersed in liquid culture and used for genetic transformation. This technology was successfully transferred to KARI-NARO (Kampala, Uganda) where embryogenic callus was produced from local cooking banana varieties. The product comprises of transgenic banana plants with varying levels of resistance to nematodes. The African countries that have banana-dependent food insecure people include Uganda, Rwanda, Ghana, Nigeria and Cameroon. Banana losses to nematodes are estimated to be 6m tonnes/year representing the consumption need of 60m people in banana-dependent countries. Banana improvement by conventional plant breeding is very difficult given its reproductive sterility and nematicide chemicals are harmful to both humans and the environment. Using nematicides is also not economically feasible for poor and subsistence farmers. This situation provides a very good opportunity for a biotechnological solution. Our approach relies on introducing into banana an additional plant gene coding for a protein (called cystatin) that prevents the digestion of parasitic nematodes. The cystatin suppresses the nematode's ability to grow, lay eggs and build to population levels that damage crops. As cystatins are part of the human diet (present in cereal seeds, eggs etc.) they have no effect on our digestion or health. Additional work funded by other donors (DEFRA) has demonstrated that cystatin has also no environmental impact on a wide range of non-target organisms. The outputs from this project provide an example of how transgenic technology can be adapted to meet the needs of the poor. A parallel strategy is described in PSP19 and PSP21 on genetically engineered rice and potato for nematode resistance, respectively.
Banana, more specifically cooking bananas from Uganda also called East Highland African Bananas (EHAB) are the main commodity for which the approach is relevant.
These outputs can be clustered with others focusing on banana improvement through classical breeding or biotechnology. Stacking transgenic nematode resistance with other traits (GM or not) such as bacterial and fungal resistance could significantly enhance banana productivity and hence benefit poor and subsistence farmers in Africa, South Asia and South America. Value could be added by clustering with outputs from other banana transformation projects or research programmes using transgenic approaches for nematode resistance in other crops. This includes outputs from RNRRS sources described in PSP19 ("Genetically engineered resistance to rice nematodes") and No21 ("Genetically engineered resistance to potato nematodes"). This also includes outputs from non-RNRRS sources focusing on GM banana research in National Research Programmes (Uganda, India, Mexico etc.) or CGIAR Centres such as IITA. How the outputs were validated: Validation of technology The callus and cell culture technologies developed for Ugandan cooking bananas (EHAB) have been validated through repeated use by scientists at the John Innes Centre (JIC) and the Kawanda Agricultural Research Institute (KARI) including Dr. Philippe Vain (JIC) and Priver Namanya (KARI). Embryogenic cell suspensions cultures have also been used successfully as target material for genetic transformation at JIC. This work is currently being summarised in a scientific publication to be submitted for review. Validation of product Ugandan cooking banana plants (Matoké type) containing an additional cystatin gene were assessed for nematode resistance in bioassays undertaken by scientists at the University of Leeds (by Prof. Howard Atkinson's group). Transgenic banana plants containing and expressing different cystatin genes were challenged with Meloidogyne incognita and exhibited levels of resistance. This was the first demonstration world-wide of the value of transgenic East African Highland Bananas (EHAB). Cystatin genes were also introduced into another type of AAA bananas (Cavendish) leading to levels of resistance to Radopholus similis. This work was published in a peer-reviewed international scientific journal:
Where the Outputs were Validated: The tissue culture technology to initiate embryogenic callus and cell suspension cultures were developed and validated at the John Innes Centre (UK) during the 2001-2002 period. These technologies were subsequently transferred to the Kawanda Agricultural Research Institute (Uganda). Genetically transformed cooking bananas containing an additional cystatin gene against nematodes were produced during the 2002-2004 period at the John Innes Centre. The University of Leeds conducted all glasshouse trials of GM bananas. These plants have not yet been evaluated in the developing world as the DFID PSRP came to an end in 2006 coinciding with banana plants being clonally propagated in vitro for field trial. The Kawanda Agricultural Research Institute has agreed to test these GM banana plants in Uganda but needs support. In addition, improving nematode resistance using a generic cystatin-base approach could impact on a broad range of nematodes and therefore be relevant to many African, Asian and South-American countries growing bananas for local consumption. Who are the Users? Technology The tissue culture technologies developed in this programme have been used by Priver Namanya in Uganda (Kawanda Agricultural Research Institute) to produce - for the first time - embryogenic callus from local genotypes. Product Transgenic banana plants containing an additional cystatin gene have not yet been evaluated in the developing world as the DFID PSRP came to an end in 2006 coinciding with banana plants being clonally propagated in vitro for field trial. The GM banana plants are maintained in vitro using resources at the John Innes Centre until further funds are secured to deliver these important outputs. Where the outputs have been used: Technology The tissue culture technologies developed in this programme have been used by scientists at the John Innes Centre (UK) as well as at Kawanda Agricultural Research Institute to produce embryogenic callus from local cooking banana genotypes. Product Products are not currently being used because of the end of the DFID PSRP funding in 2006. The Kawanda Research Agricultural Institute has agreed to test the transgenic banana plants containing an additional cystatin gene for nematode resistance in Uganda providing that funding can be secured. Scale of Current Use: Technology To date, the technologies developed in this programme have been used in the UK and in Uganda. Publication of this work should promote further use. Product Transgenic banana plants containing an additional cystatin gene have not yet been evaluated in the developing world because of the end of the DFID PSRP in 2006. Policy and Institutional Structures, and Key Components for Success: The following factors have contributed to the promotion and adoption of the outputs:
http://www.biology.leeds.ac.uk/nem/crops/crops.htm http://www.dfid-psp.org/Research/CropTrans2.html http://www.jic.ac.uk/staff/philippe-vain/banana.htm Presentation of the outputs at international meetings, especially those in Africa, Asia and South America:
Presentation of outputs in DFID reports:
Biotechnological solutions should be addressing local needs and have a strong biosafety background. This requires an assessment under field conditions in different locations, using different production systems and over several years by national programmes. Further diffusion to growers via participatory breeding schemes can further contribute to the evaluation and ensure that transgenic plants are fit for purpose. The attitude of local governments towards biotechnologies is also a key factor for success. In this regard, the Ugandan government is committed to fund biotechnology-based approaches to enhance cooking banana production. Lessons Learned and Uptake Pathways Promotion of Outputs: The technology is promoted worldwide through peer-reviewed scientific publications, web-based information and the Ugandan initiative on the application of biotechnological methodologies (see section C of this document). The product (i.e. transgenic cooking banana plants with levels of resistance to nematodes) are not currently being used in developing countries. However, the Kawanda Agricultural Research Institute has agreed to test these plants in Uganda providing that funding can be secured. Project clusters PSP19 and PSP21 provide examples of promotion and uptake pathways for transgenic rice and potato plants containing additional cystatin genes for nematode control, respectively. Potential Barriers Preventing Adoption of Outputs: Technology There are no barriers to the adoption of tissue culture and transformation technologies as the know-how is freely available and actively disseminated through the Ugandan biotechnology initiative (see section C of this document). The technological outputs do not bring additional intellectual property right constrains to existing transgenic strategies for banana improvement. Product The end of the DFID PSRP funding in 2006 has stopped the planned translational research to developing countries. Current barriers are:
How to Overcome Barriers to Adoption of Outputs: No changes are required for the adoption of the banana tissue culture and transformation technology by the international scientific community. However, many changes are needed to remove or reduce the barriers to the adoption of GM crops in Africa and to a lesser extend in Asia. Helping African countries to develop and implement biosafety regulations is a pre-requisite. Developing transgenic strategies with a strong poverty focus (i.e. with relevant traits in relevant species) and a public-good approach are also key. Evaluation of the GM crops by participatory breeding after initial testing by national programmes could help to demonstrate the benefits to poor or subsistence farmers. Maybe more consideration should also be given to the voice of developing world farmers who would like to explore for themselves the potential benefits of biotechnologies to improve their livelihood. Lessons Learned: The product (i.e. transgenic cooking banana plants with levels of resistance to nematodes) is not currently being used in developing countries. However, the following factors are foreseen to be instrumental in getting the outputs used by the largest number of poor people:
PSP19 ("Genetically engineered resistance to rice nematodes") and No21 ("Genetically engineered resistance to potato nematodes") provide examples of the lessons learnt in the best ways to get GM crops containing additional cystatin gene(s) against nematodes used by the largest number of poor people. Poverty Impact Studies: The product is not currently being used in developing countries and to date, no GM banana has been released / commercialized worldwide. The impact of GM banana on poverty is therefore difficult to assess post-release. The specific issues of the benefits from transgenic nematode resistance have been considered and the extent of need in terms of nematode loses to banana is detailed above.
How the Poor have Benefited (including gender and other poverty groups): To date, no GM banana has been released / commercialized worldwide therefore only pre-commercialisation data are available. However, the socio-economical and environmental impact of other GM crops - such as insect resistant B.t. cotton and B.t. maize - currently commercialised in developing countries - such as China, India or South Africa - has been the subject of many studies (Carl E. Pray et al. 2002, Five years of Bt cotton in China - the benefits continue, The Plant Journal 31:423-430 ; http://www.isaaa.org/). It is estimated that China has enhanced its farm income from biotech cotton by $4.2 billion in the 1997-2004 period. In 2005, 6.4 million small farmers were growing B.t. cotton in China. However, benefits of a different type of B.t. cotton in India have been less clear, highlighting that GM approaches should be tailored to local environments (such as high pest and pathogen pressures), agronomic practices and needs. Direct and Indirect Environmental Benefits: FAO has identified our approaches as the best prospect for biosafe banana nematode control. The use of pesticides is not appropriate for most poor or subsistence farmers who lack both training in proper chemical use and protective clothing. Nematicides also belong to the most hazardous WHO classes a & b and are used routinely on banana plantations with considerable harm to human populations (i.e. in Ecuador) plus widespread environmental harm. However, pressure to use nematicides is likely to intensify when other approaches fail to be effective. Cystatin-based transgenic approaches can deliver alternative and generic approaches to chemical control of nematodes in banana with considerable environmental benefits. In addition, most bananas are sterile due to their triploid nature providing a natural containment system to prevent gene flow through cross-pollination. All GM banana field trials will be carried out under secure conditions and experiments can be terminated before fruit has set. The latter measure ensures fruit pilfering cannot occur. Adverse Environmental Impacts: The cystatin-based approach to control nematodes will have no adverse environmental impact. Additional work from the University of Leeds (and funded by other donors) has demonstrated that cystatins have no environmental impact on a wide range of non-target organisms. This work has been published in the following peer-reviewed articles:
Currently, no efficient mean of producing GM banana plants free of selectable marker genes exists and herbicide resistance genes are often used to recover transgenic plants during the transformation process. In GM bananas, these herbicide resistant genes do not pose a problem of horizontal gene transfer as plants are sterile and cannot cross-pollinate with wild relatives. Coping with the Effects of Climate Change, or Risk from Natural Disasters: The principal and direct consequence of nematode damage is to stunt root systems. This makes plants are less able to obtain water and nutrients from soil. Common symptoms of nematode attack are wilting and mineral deficiencies. Our approach could help poor farmers to cope with environmental pressures which can be amplified in cases of droughts associated with climate change. Relevant Research Projects,
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