Improving nutrition for the developing world

Recdent studies have shown that the antioxidant properties of carotenoids, vitamins found in many foods, boost humas defences against many diseases. Raising carotenoid levels in staple crops like maize and rice will thus have a real impact on health in the developing world, as Paul Christou of the BIOFORCE project explains. .

Natural pigments found in a wide range of foods, including fresh fruits and vegetables, egg yolks and salmon, carotenoids bring a number of important health benefits. Studies have shown that they both enhance the immune system and protect cells from damage, making carotenoids and other vitamins enormously relevant in terms of improving overall health in the developing world, a prime motivation behind the work of the BIOFORCE project. “The applied objective of BIOFORCE is to create cereal grains, primarily maize and rice, with as complete as possible a nutritional complement. By that I mean packaging as many different vitamins and minerals into a single seed as possible. We then plan to deliver them to poor people in developing countries through the appropriate channels,” says Paul Christou, the project’s Principal Investigator. The nature of the environment in which many of these crops will be cultivated means they must be extremely resilient, an issue of which Christou is well aware. “We aim to build the plant’s defences so as to allow them to grow in hostile environments, primarily in sub-Saharan Africa and the Indian sub-continent,” he continues. “We are trying to build in resistance to insects, and also a mechanism to enable plants to survive attacks by parasitic weeds.”

Carotenoids

This work is underpinned by recent research advances which allow the introduction of an unlimited number of transgenes into plants. This can now be done in a way that will allow researchers to recreate the metabolic pathways leading to different vitamins and other important compounds. “We are working on vitamin A and a number of other carotenoids, vitamin B9 –folic acid – vitamin C and vitamin E. In terms of minerals we are looking at accumulating four key minerals in the seeds – iron, zinc, selenium and calcium,” explains Christou. BIOFORCE is focusing on four particularly important carotenoids in terms of nutrition þ-carotene, lutein, zeaxanthin and lycopene – yet efforts to improve nutrition face both socio-economic and cultural hurdles. “Africans, especially poor Africans, eat white maize, and feed their animals yellow maize, because they believe that white maize is purer and better for humans,” says Christou. “The problem is that yellow maize has only a small amount of carotenoids, especially lutein and zeaxanthin, while white maize has none. So they are feeding their animals more nutritious maize because of these cultural factors. We are trying to change the maize people grow in Africa and create maize which would deliver far higher levels of nutrients.”

Genetically engineered crops such as these are not entirely new. Golden rice, the scientific details of which were published in 2000, is genetically engineered to accumulate high levels of þcarotene; however, Christou says BIOFORCE’s work goes far beyond what has been achieved in this area so far. “We have been able to produce rice plants with at least 2-3 times the levels of þcarotene that is found in Golden Rice,” he stresses. Similarly with maize the project has been able to increase carotenoid levels by well over 150-fold above levels found in any other maize variety, something which Christou says could not have been achieved by conventional means. “You are limited by the maximum levels of carotenoids that may be present in the specific varieties of maize found in different places. This is a very small amount,” he explains. “Our starting material is one of the most popular inbred maize varieties, and is similar to most contemporary varieties of maize grown in sub-Saharan Africa. We go directly into existing maize varieties, not into model systems. So we short-circuit the time-frames that might otherwise have been needed to introduce our maize plants into a breeding programme – by doing that we save 2-3 years over the normal production cycle.”

Protecting crops

Protecting crops against pests is crucial to ensuring that these gains in terms of both crop productivity and quality are sustained. Crops in parts of the developing world are vulnerable to diseases and pests such as lepidopteran insects, which bore into and eat the stalks of maize plants, with severe consequences. “Lepidopteran insects make the plant very weak, causing it to fall down and leaving the farmers unable to harvest it. Additionally, if the plants are not damaged they are less sensitive to opportunistic fungal infections, which are known to cause problems in maize, through the production of mycotoxins, which are severely carcinogenic compounds produced by these fungi,” explains Christou. These are issues the project is addressing by adding genes to the plant and hence protecting it more effectively. “We are introducing a number of genes into plants to protect them against common insect pests they are likely to encounter in Africa. We are targeting the most significant maize pests throughout sub-Saharan Africa, and because of the types of genes we are putting into the plants we are confident of getting very good results.” outlines Christou. “We expect the data to show that these plants are protected not only against insects, but also against opportunistic fungal infections which would result in the accumulation of very carcinogenic products.”

These types of plants are thus much safer than maize grown using conventional methods, which remains susceptible to infection. In developing countries food security is a prominent issue, and although BIOFORCE is focused on rice and maize, Christou is keen to stress that the project’s technology is not limited to specific crops. “We could also work on other staple crops aside from rice and maize. In fact, work is currently ongoing in other laboratories on potatoes, cassava and millets,” he says. Focusing on staple crops helps ensure the project’s work has a wide impact, yet it is also important that the varying nature of nutritional needs in the developing world be taken into account, something to which genetic engineering is well adapted. “We can really target people’s specific nutritional needs – this is one of the greatest powers of plant genetic engineering.

We can modify crops in a very targeted way that is not achievable through any other technology, and can do this much safer, quicker and a lot more economically than previously,” says Christou. “We try to find public institutions or centres of excellence – in either India or South Africa – and work with the people who know the local problems, the culture, and what people want, need and will accept.

It’s an iterative process and we need to learn about the culture of the country in which we’re working, to make sure that what we produce will not only be effective, but also acceptable to the target audience.” This local involvement is crucial to ensuring BIOFORCE’s work brings long-term benefits to the areas at which it is targeted.

The project is also in the process of establishing links with major international philanthropic organisations, including the Rockefeller and Gates Foundations, illustrating the wide importance attached to their work. “We hope to take advantage of their infrastructure in terms of local links with stakeholders and government agencies,” explains Christou. Putting the right technical and logistical mechanisms in place will help maintain high vitamin levels in future crops. “We are looking at a sustainable, durable uptake mechanism which I would split into two parts – science and utilisation. The science part is the easier bit, because once you have created, tested and trialled a transgenic crop – which we are doing now – you can be confident of stable, consistent performance from year-to-year,” continues Christou. “The other side of the equation is what happens to that plant once it’s been delivered to the people who need it. We are working hand-in-hand with collaborators in the countries we are targeting, and it’s through their continuous and sustained involvement that we can ensure year-to-year consistency in terms of cultivating the product and improving nutrition in the developing world.”

Paul Christou has been working in the field of applied plant biotechnology for almost 30 years. He holds a PhD degree in organic chemistry and plant biochemistry from University College London, UK.

He was senior scientist at Agracetus Inc, a plant biotechnology startup in Madison, Wisconsin, now part of the Monsanto company, and subsequently he was head of the Molecular Biotechnology Unit at the John Innes Centre, Norwich, UK. He also worked at the Fraunhofer Institute of Molecular Biotechnology and Applied Ecology, Aachen/Schmallenberg, Germany.

He is currently an ICREA Professor at the University of Lleida, Spain.

Published: Monday, 6th September 2010 by Adelle Kehoe