A blight resistant potato that is also Potato Virus Y resistant, in several popular varieties

Genetic technologies have many exciting applications in crops, and one of the most important is making our crops more disease resistant. Providing plants with the ability to fend off disease without requiring pesticides has immense benefits for our environment, economy and health.

PiperPlus 1.0

Professor Jonathan Jones’ group at The Sainsbury Laboratory, Norwich, has successfully developed a late blight resistant Maris Piper potato, PiperPlus 1.0, which is ready to be commercialized when the UK puts in place workable regulation for crops improved with the genetic modification (GM) method. Not only does PiperPlus 1.0 thrive without the weekly fungicide sprays needed to control late blight, it also has other qualities that will lead to less food waste during production and provide a higher quality product for consumers.

Late blight is still an issue

Potato late blight was the biotic cause of the Irish Potato Famine in the 1840s and still plagues UK farmers today. Much of the success in potato agriculture is due to improvements in fungicide formulations and spray regimes, but these need to be continuously adapted as strains become insensitive or resistant to the chemicals. Another benefit of protecting crops with genetics instead of chemistry is that fewer tractor journeys are required, reducing CO2 emissions and soil compaction. In addition, there is less selection for genes that compromise our capacity to control human fungal diseases, and less damage to benefical fungi in the soil.

“Chemical control methods work,” comments Dr Agnieszka Witek, lead scientist in the PiperPlus project, “but at a cost.”

What do farmers think?

“We expect much from the land and our farmers:- food, biodiversity, net zero, and sequestration. So, using all the tools that are available to us is essential if we want to achieve all this. And making the most of tools developed by our own scientists from public money is essential to do that. By using genes already in wild relatives of potato to combat diseases, and providing consumer benefits whilst retaining all the attributes of these varieties - it’s as neat as it gets.” - Tony Bambridge, B&C Farming, Norfolk

"Having been involved with new tech for 25 years it is gratifying to find that at last we as farmers are finally moving towards the starting line. We will be able to fight food poverty and climate change without one hand (or perhaps two) tied behind our backs." - R W Hill Farms Ltd.

“If population growth is to be sustained by lower input agricultural systems, the optimisation of plant productivity and nutritional value by adopting GM breeding techniques is essential.” - Tom Will, Managing Director and Agronomist for the Vegetable Consultancy Services

“The ability to use cutting edge molecular tools such as GE and GM provides an unparalleled opportunity to efficiently optimise the plant, enable us to achieve our food productivity goals!” - James Fortune, BSPP Ambassador and Consultant Research Agronomist for the Vegetable Consultancy Services (VCS).

Making your favourite potato less reliant on fungicides

Some wild relatives of the potato, such as Solanum americanum, are blight resistant. Scientists in the Jones group successfully isolated blight resistance genes from Solanum species and transferred three of them to Maris Piper potato, conferring full late blight resistance. This led to the development of the PiperPlus project. The PiperPlus 1.0 potato is also resistant to tuber blight, which affects tubers during storage and can lead to significant losses post-harvest.

A small selection of popular Solanaceae species.

Late blight isn't the only problem, meet Potato Virus Y

During a field trial in Cambridge in 2020 almost all our potatoes became infected with Potato Virus Y (PVY).

Most potato varieties in the UK are PVY susceptible. Potato Virus Y is one of the most important viruses that affect potato production and is transmitted via sap-sucking aphids. The virus can be transmitted in potato tubers which means that if they are used as seed potatoes, the viral load will progressively increase.

About 75% of the UK’s seed potatoes are grown in Scotland due to its cooler climate which reduces aphid populations. A PVY resistant potato would mean that seed potatoes could be grown in warmer climates, and that England would be able to produce its own seed potatoes.

Jonathan Jones’ group in collaboration with Polish colleagues isolated a PVY resistance gene (Rysto) from a wild potato relative, Solanum stoloniferum. The first PVY-resistant and blight-resistant PiperPlus 2.0 lines have already been planted in a field trial to test their performance.

What about other potato varieties?

The team would also like to confer blight and PVY resistance to other valued potato varieties in the UK. Charlotte, the home grower’s favourite, would benefit from resistance to late blight and PVY; the new line will be called Charlotte Plus, and several candidate lines are being trialled this year. In addition, the variety Hermes, which has high dry matter and is suitable for manufacturing crisps, is also being modified to provide late blight and PVY resistance, and improved tuber quality.

Commercialising PiperPlus

BioPotatoes Ltd is a small UK based company which holds the licences to commercialise the five genes in Piper Plus. Jeff Hooper, Chairman of BioPotatoes is confident the UK government will shortly see sense and make it possible for GM crops to be grown in England and Wales.

"The UK has a long history of excellence in plant science and world class scientists working at the John Innes Institute have produced some remarkable crops over the past two decades. It is time for the UK to take the lead in Europe and capitalize on our expertise in this area."

"The UK lags behind because legislation inherited from The EU makes it impossible to bring GM crops to market by imposing stringent regulations on their approval which are prohibitively expensive to undertake. This is despite the fact that GM crops have been consumed for over 30 years without one single instance of a proven risk, and in Africa alone it is estimated that 1.95 billion people have benefited from consumption of GM crops."

"Pretty well every continent is using the technology apart from Europe and it has bought substantial benefits to farmers not only in developed countries like the US, but in Africa and South America."

Regulatory hurdles prevent UK farmers from accessing these varieties

Transgenic potatoes such as these are currently regulated under the same strict GMO legislation as in the European Union, making it unlikely to end up on UK supermarket shelves any time soon. A new Precision Breeding Bill received Royal assent in April 2023 to reduce the regulatory load on Precision Bred Organisms which are genetically engineered organisms that contain changes which could have been achieved via conventional breeding methods. Because potato and the wild relatives used for resistance genes are not able to be cross bred, they would not qualify as Precision Bred Organisms under this act.

“If you have a potato that is inherently resistant to disease and shows reduced post-harvest losses, which will need less pesticides and reduce food waste - to me that’s obviously a good thing” says Jonathan. “But we still need legislation that enables plants improved with the benign and effective GM method to be brought to public use without an excessive regulatory burden”.

“We’ve been able to integrate so many excellent qualities within the Maris Piper that could greatly benefit our environment and our people.” says Agnieszka, “Developing an even better Maris Piper, Charlotte and Hermes potato for the UK is something we would love to be able to achieve.”

Field trail plots of PiperPlus 2.0 and Charlotte Plus were planted out at the experimental farm in Norwich last year. The best lines from that evaluation are currently being tested in field trials in NIAB, Cambridge.

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