The natural mutation of a variant pea that can help humans and animals to absorb more protein is tipped to provide a headstart for seed breeders looking to introduce a more nutritious, cost-effective pea. Produce Business UK finds out more about the study conducted at the John Innes Centre (JIC) in Norfolk that could see peas gain greater prominence as an increased source of protein, behind meat, poultry, fish and eggs
Led by Dr Claire Domoney, the group at JIC used non-GM methods to develop a new strain of pea that doesn’t contain the several so-called anti-nutrients or trypsin inhibitors found in peas and other legume seeds that stop proteins being absorbed fully from the diet of humans, poultry and livestock.
Because of the presence of these inhibitors, the body is unable to process bean and legume proteins nearly as efficiently as plant proteins, which means the proteins found in beans, peas and other legumes have poor digestibility.
The EU Grain Legumes Integrated Project (GLIP), which part funded JIC’s research, claims grain legumes such as peas, chickpeas, beans and lupins have a significant role to play in European agriculture because of their value as an important source of vegetable protein for humans and animals, in addition to their beneficial impact on the environment.
However, the use of these crops in European farming systems is relatively limited compared with the rest of the world because of problems with nutrition, disease, drought and plant morphology.
Finding the solution
To address the issue, the scientists at JIC identified the proteins that were responsible for inhibiting digestive enzymes, as well as how and when the genes encoding these become active in seeds. While screening 2,822 germplasm lines for variants of the genes, they discovered one example of this line that doesn’t contain the protein inhibitor.
That was a wild pea variant collected from Turkey and from a different pea species – the Pisum elatius line – which was then crossed readily with the typically cultivated pea species, Pisum sativum to result in the so-called ‘novel pea’.
“We needed to cross the variant pea with cultivated forms to make our experiments on the seeds easier,” explains Dr Domoney. “The wild seeds are small, with a thick seed coat, so we introduced the mutation into a cultivar by crossing them to give us bigger seeds with a thin seed coat.”
JIC claims the new pea is not expected to have a different taste because the proteins that have been removed are not linked to the development of flavour. Neither is it expected to cost more than conventional peas that are currently available.
Headstart for breeders
Since non-GM methods were used, Dr Domoney anticipates widespread adoption of the variant pea line and believes it could reach the market within five years. Breeders, including Limagrain and Wherry & Sons, are already apparently showing an interest.
Dr Domoney says the next step for breeders looking to develop the pea for commercial use and human consumption will be to cross the novel pea several times with current cultivated breeding lines in order to get the mutation and therefore the improved quality trait into a good variety for the field.
“Their job will be a lot easier as they will use our genetic information to identify the lines carrying the new trait, which will speed up the breeding,” she points out. “If breeders work alongside food manufacturers and nutritionists, there will be an understanding of what is required for the different markets.”
Increased protein for humans
Market-wise, although Dr Domoney says pea and legume inhibitors have been a “long-standing problem” in animal feed manufacture (meaning the new pea will cut costs for farmers because fewer of the novel peas will give livestock the same or higher nutritional benefit than standard peas), she adds that those who grow, sell and market peas for human consumption could also benefit from the development.
“Pulses are a staple in many other countries where they form an important part of the human diet,” Dr Domoney tells Produce Business UK. “In UK, and Europe more generally, humans do not rely on pulses to provide them with protein but there are exceptions of course – vegetarians and those with specialist diets, where a higher quality plant protein source is very desirable.
“The animal feed market will be an obvious primary target for breeders but it is clear that these peas could be a source of increased protein for vegans, vegetarians, those with coeliac disease and other specialist dietary needs.”
Indeed, Chris Collings, president of the British Edible Pulse Association (Bepa), which represents the processors and users of British-produced pulses (mainly peas and field beans), says the development would be of great interest to the sector.
“In the UK, the majority of peas [produced] end up for human consumption, rather than for animal feed,” he explains. “I’m unaware of which variety John Innes has [developed] but it takes four to five years to breed [a pea plant], so in terms of commercial production it would be interesting to look at this in 18-20 months’ time when it comes into commercial availability.”
Tim Mudge, commercial services manager at British Growers and head of the Pea and Bean Producers’ Organisation, says the pea could end up being more suited to the foodservice industry than the fresh trade. “As far as I’m aware, it’s not a traditional vining variety that we’d harvest and freeze. It’s more of a pulse crop for use in mushy peas or other protein crops.”
Given the high demand for pea protein as an ingredient, Dr Domoney claims she wouldn’t be surprised if breeders target this sector too, although she is quick to point out that the decision on which markets to target will be made by the breeders.
“Sources of protein with high nutritional value are becoming more and more in demand, and particularly for specialist diets,” she says. “The use of pea flour as an ingredient are evolving rapidly – for example, in the development of sports and health bars.”
According to this newsletter from the USA Dry Pea & Lentil Council, the protein that can be extracted from peas has a bright future for the allergen-free market. Indeed, there is a growing trend to use pea protein as a ‘clean’ ingredient to replace soy in items like snack bars or to substitute eggs in mayonnaise.
Peter Smith, arable crops director at Wherry & Sons, which claims to breed all the popular varieties of winter beans currently being grown in the UK, agrees that JIC’s development holds benefits for food consumption all over the world.
“It’s a fairly major breakthrough,” he states. “The removal of inhibitors in peas is an example of one of many traits which should enable the industry to move forward with a nutritionally improved crop benefiting throughout the food chain.
“Any major anti-nutritional elements that breeders can screen out when they put a trait such as this into the background of their other material is a direction they’d go in, as long as there are not too many pay-offs agronomically speaking. For instance, some traits in peas or beans are there for a reason as they can act as natural repellents to pests. You have to weigh up the balance between the two.”
Initially, Smith says Wherry & Sons would definitely look at the pea for animal feed but would also assess its role in human consumption. “It’s a box ticked,” he explains. “We know trypsin is an issue (it’s tested for in France) in the same way that the tannins in faba beans sometimes cause problems with the human gut, while for some it can cause favism.
“You’d need to get this new pea into a commercial background and cross it against whatever germplasm the breeder thinks would be suited for it,” he adds. “The breeding process would probably take six to eight years.”
The novel pea will also offer advantages to UK breeders and growers targeting markets outside the UK, where Dr Domoney says the concentration of the protein inhibitors in seeds is measured not just for animal feed formulations but also as part of the registration process for new varieties.
Value of science
The scientists claim the development of the new pea strain is a clear example of the value of diverse germplasm collections, such as the pea collection at JIC. “Being able to generate and/or discover genetic variation for traits of interest to growers is essential for improving crops,” explains Dr Domoney.
Smith agrees, adding that genetics and targeted research in pulse crops is aiding the UK industry to achieve specific needs.
“Any work JIC does is a great benefit because they do the pre-breeding work that breeders don’t have the time or money to spend,” he points out. “As pulses potentially become grown on a wider scale in the UK we must remain focused on producing a better product in comparison to imported pulses and protein crops.”
Dr Domoney’s group will now follow up its proof of concept study with feed nutritionists who will measure the difference the improved peas make to animal digestion.
The research was funded by Defra’s Pulse Crop Genetic Improvement Network, EU Grain Legumes Integrated Project and the Biotechnology and Biological Sciences Research Council. The JIC pea germplasm collection is part-funded by Defra.
Full details of the study – titled Eliminating Anti-Nutritional Plant Food Proteins: The Case of Seed Protease Inhibitors in Pea – are published in PLOS ONE.
