The PIPs That Help Plants Protect Themselves
November 27, 2017
Investment & Innovation
By Hannah Brown
From coffee to cabbage, nearly all crops produce their own natural pesticides to protect them from damage, but often it’s not enough to keep them healthy and alive – and that’s where plant biologists can lend a helping hand. By using plant biotechnology, scientists can help crops produce pesticides that are naturally found in other species – these are referred to as plant incorporated protectants (PIPs).
PIPs are produced when scientists take the genetic information required to produce a pesticidal substance and introduce it into the target crop’s own genetic material. This allows the crop to produce its own additional ‘biological pesticide’ and enhance its protection.
Not only can PIP crops help reduce the applications of crop protection products, they are also highly targeted, acting on specific pest species helping to conserve beneficial insects while minimizing risk to human health.
The Bt example
Bt crops are one of the most widely adopted examples of this technology, grown globally last year on over 23.1 million hectares (about the size of Romania!) and they currently represent 85% of all cotton grown in the US. Bacillus thuringiensis (Bt) is a soil dwelling bacterium which produces a range of insecticidal proteins – it has been widely used as a liquid biological pesticide by organic and conventional farmers for decades. Biotech Bt crops were introduced in 1996. They have been engineered to contain the genetic material to produce these Bt insecticidal proteins enabling the crop to produce its own biological pesticide.
One issue surrounding the use of PIPs, like Bt crops, is the development of resistance by insects in the field, much the same way as insects develop resistance to crop sprays. The widescale use of Bt crops has placed a high evolutionary pressure on pests to overcome their susceptibility to Bt, but plant scientists are developing solutions. One effective tool to reduce resistance is to deploy a combination of PIPs in a crop. For example, Bt produces a range of proteins that can be used to control insects. Introducing alternative Bt insecticidal proteins to mimic the natural ‘pesticidal pyramids’ found in the Bt bacteria is an effective tool at reducing resistance evolution.
Additionally, the plant science industry is searching for new non-Bt strains of bacteria with pesticidal properties to provide new sources of natural insecticidal proteins to be used as PIPs and biological pesticides. Plant scientists are also utilizing new biotech techniques like RNA Interference (RNAi). This process is highly specific and can be engineered to target individual species of insect. For example, RNAi has been used to develop a PIP in biotech corn to combat corn rootworm, a pest which is estimated to cause losses of over one billion dollars annually in the US alone.
PIPs like Bt crops are one of the longest running and most successful applications of biotechnology. Through identifying new sources of natural insecticide proteins and adopting new PIP technologies like RNAi this crop protection tool will continue to support sustainable agriculture as part of an integrated pest management strategy.
Hannah Brown is a PhD student at the Sainsbury Laboratory, UK, working in the field of crop disease research, specializing in understanding the activation of the plant immune system.