The Sainsbury Laboratory discusses breeding techniques that reduce dependence on chemicals
Potato performance and quality is always a hot topic. At The Sainsbury Lab, in Norwich, scientists have been using the latest methods enable some improvements for the humble spud. We asked Jonathan Jones and his colleagues Agnieeszka Witek and Sebastian Fairhead for an update.
- TSL has been working on improving the quality of potato tubers – are there any insights that TSL has gained that will help to mitigate the challenge to farmers created by the withdrawal of chemicals for potato storage?
Our main focus over the last 20 years has been resistance to late blight. We have now established Maris Piper lines with complete late blight resistance. Remarkably, they also have complete resistance to tuber blight, so these lines could also reduce losses in storage.
The sprout suppressant chlorpropham (CIPC) has been banned by the EU. The EU requires member states to withdraw authorisations for CIPC-based products by 8 January 2020 and ensure all existing stocks are used up by 8 October 2020 (NFU, 2020). Effective sprout suppression is essential for stored potato quality. CIPC is particularly important for potato storage in the processing sector because crops destined for the processing market must be stored at relatively warm temperatures (6-13°C) in order to maintain frying quality (CIPC, 2020). Although lower storage temperatures inhibit sprouting, they also promote conversion of tuber starch to the reducing sugars, glucose and fructose. As raw potatoes are sliced and cooked in oil at high temperature, the accumulated reducing sugars react with free amino acids in the potato forming unacceptably dark-pigmented crisps or fries. At TSL, we used the technology by J.R. Simplot that lowers the activity of tuber invertase enzyme which converts sucrose to glucose and fructose. Such potatoes accumulate much lower amounts of reducing sugars upon low temperature storage, thus maintaining their processing quality.
- Are there any advanced breeding technologies that don’t require GM but will still accelerate the development of more resilient crops?
There are, but we are not using them in this project. Gene editing enables specific defined changes to be made in the plant genome sequence, enabling certain improvements to be achieved. This technology has huge potential to bring agronomically beneficial traits into commercial crop varieties. However, we could not deliver the potato improvements we have achieved using current gene editing methods.
- Scientists argue that gene editing should not be in the same category as GM – can you explain the difference between these technologies? Is the restriction on the use of gene-editing still being discussed by legislators/is the situation likely to change?
Simply put, using the GM method, DNA sequences can be moved from one plant to another to (for example) elevate disease resistance. Gene editing usually involves more minor changes, that specifically change or inactivate the DNA sequence of a gene where such changes could elevate crop performance, and do not involve adding new DNA.
The sole shortcoming of the GM method is that it is difficult to control where in the recipient plant DNA the added DNA will insert. Using more advanced editing methods in the future, it may become possible to deliver added DNA to defined locations in the genome.
- Looking to the future and the UN Sustainable Development Goals – how do you think the work at TSL will help us to feed the world’s population better?
Throughout the world, crop yields are reduced by pests and disease. In developed countries, farmers can control these threats by application of chemicals, but in developing countries, this technology is not available to poor farmers. Our goal at TSL is replace chemistry with genetics for control of important crop diseases, so that farmers and consumers everywhere can benefit from reduction in the need for agrichemical applications, by enabling creation of crop varieties that carry genetic resistance.