Pea, bean and lentil belong to the legume family and have great promise as net-zero, climate-resilient crops for the future. They have the potential to be an important part of the solution to reduce the impact of agriculture and boost food production on our planet. However, to realise these benefits there are challenges to overcome. This is where John Innes Centre researchers and collaborators believe they can help.

Pulses provide a healthy source of protein, fibre, minerals and complex carbohydrates. But these plants have another astonishing feature – they form a close interaction with microbes that can harvest, or fix, nitrogen from the air and convert it to natural fertiliser. This beneficial plant-microbe arrangement means that most legumes can thrive without costly and damaging nitrogen fertilisers.

With a long history of genetic research and an international collection of diverse pea germplasm, the John Innes Centre is well placed to study how both the nutritional traits and environmental resilience of pea can be improved. In addition, germplasm collections of other legumes, mainly lentil and common bean, have recently been added.

The Defra-funded Pulse Crop Genetic Improvement Network (PCGIN), led by group leaders Professor Janneke Balk and Dr Sanu Arora, is a five-year programme with £3 million funding and involves five different UK partner organisations. It aims to understand the genetic variation for specific traits in pulse crops and develop new genetic resources. This will form the basis of a toolkit for plant breeders who develop new varieties of pea, faba bean and lentil for farmers in the UK.

One of the PCGIN-funded tasks taken on by Professor Balk and Dr Arora, in collaboration with Professor Lars Østergaard who recently moved to the University of Oxford, is to create a new genetic resource for pea.

To generate a large population of lines with small genetic changes, they have used a conventional breeding technique called ‘induced mutation’, that creates small changes in a plant’s DNA by exposing a plant or seeds to chemical or physical stresses.

Sequence analysis so far indicates that the new pea lines have small genetic changes in virtually all of the 30,000 genes in the genome. If such a change disrupts a gene function, this will manifest itself in altered traits and link the trait to specific genes, which is very useful for plant breeders.

In 2024, 3,000 plants were grown in our glasshouses to give a glimpse into the range of traits in this pea population. Observations of visible traits (leaf morphology, plant size, flower colour and seed shape) are stored in an accessible database. A DNA sample has been collected from each plant and the seeds will be carefully archived.

This is the start of a community resource that will enable the development of improved legume crops which are more nutritious, resilient to evolving pests, diseases and a changing climate.

For Professor Balk this is a novel experience: “For most of my career I have been focused on investigating and understanding the function of the proteins involved in iron transport and storage in plants. The work we’re doing here to create a resource that can support the long-term development of a crop is new to me and I’m enjoying the process.”

Researchers who want to study a specific trait can find plants of interest and order the seeds. Also, if they are interested in a specific gene, the TILLING service at the John Innes Centre can screen DNA samples for mutations. The plan is to sequence the genomes from all 3,000 plants, but this will require additional funding.

Did you know?

Nearly half of the protein in the human diet comes from plants, mostly pulses, which are the dried, edible seeds of legumes. Legumes are gluten-free and have a low glycaemic index, making them a good choice for the health of the planet and human health.

The identity of the pea used for creating the new mutant population was chosen carefully. Professor Balk explained: “The line we have used is the John Innes ‘lab rat’ of pea – JI2822. It has a short seed to seed generation time, and it only grows to around 50cm tall. This makes it perfect for this type of study where we need lots of plants and many generations.

“In addition to morphological traits, we have also started to screen for nutritional changes, such as increased iron. Tegan Tyzack, a PhD student, found an iron-accumulating plant in the first set of 400 plants and is taking this further to find the genetic cause. Increasing the iron content of plant-based foods is important for human health in the long term, as many people switch to diets with less meat,” said Professor Balk.

Dr Arora, co-lead of PCGIN, and her team focus on understanding the genetic basis of disease resistance in the context of a changing climate, and developing more resilient legumes.

Her initial priority is to screen a subset of the mutant pea population for resistance to root rot and downy mildew pathogens.

Dr Arora explains, “Working with a crop like pea comes with many challenges, from limited funding and genomic resources, to being part of a relatively small community of researchers. But, over the years, PCGIN has been a fantastic programme for developing resources accessible to the entire community. The next step is to enable the cultivation of crops like lentil and Phaseolus (or common bean, used for baked beans) in the UK.”

“Working together with industry, farmers, food producers and the government, we hope to be able to improve diverse legumes so that they become viable crops for the UK, supporting sustainable agriculture, and producing healthy food,” Professor Balk concluded.

The Defra-funded Pulse Crop Genetic Improvement Network is a consortium of UK research organisations led by the John Innes Centre. PCGIN supports researchers and industry to provide improved breeding material that will better enable the development of climate resilient pea, faba bean and other pulses in the UK.

The partners involved are the University of Reading, NIAB in Cambridge, the Institute of Biological, Environmental and Rural Sciences (IBERS) at Aberystwyth University, and PGRO, the Processors and Growers Research Organisation, Peterborough.